drivers/usb/gadget/function/f_fs.c

   1 /*
   2  * f_fs.c -- user mode file system API for USB composite function controllers
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  * Author: Michal Nazarewicz <mina86@mina86.com>
   6  *
   7  * Based on inode.c (GadgetFS) which was:
   8  * Copyright (C) 2003-2004 David Brownell
   9  * Copyright (C) 2003 Agilent Technologies
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  */
  16
  17
  18 /* #define DEBUG */
  19 /* #define VERBOSE_DEBUG */
  20
  21 #include <linux/blkdev.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/export.h>
  24 #include <linux/hid.h>
  25 #include <linux/module.h>
  26 #include <linux/uio.h>
  27 #include <asm/unaligned.h>
  28
  29 #include <linux/usb/composite.h>
  30 #include <linux/usb/functionfs.h>
  31
  32 #include <linux/aio.h>
  33 #include <linux/mmu_context.h>
  34 #include <linux/poll.h>
  35 #include <linux/eventfd.h>
  36
  37 #include "u_fs.h"
  38 #include "u_f.h"
  39 #include "u_os_desc.h"
  40 #include "configfs.h"
  41
  42 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  43
  44 /* Reference counter handling */
  45 static void ffs_data_get(struct ffs_data *ffs);
  46 static void ffs_data_put(struct ffs_data *ffs);
  47 /* Creates new ffs_data object. */
  48 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
  49
  50 /* Opened counter handling. */
  51 static void ffs_data_opened(struct ffs_data *ffs);
  52 static void ffs_data_closed(struct ffs_data *ffs);
  53
  54 /* Called with ffs->mutex held; take over ownership of data. */
  55 static int __must_check
  56 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  57 static int __must_check
  58 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  59
  60
  61 /* The function structure ***************************************************/
  62
  63 struct ffs_ep;
  64
  65 struct ffs_function {
  66         struct usb_configuration        *conf;
  67         struct usb_gadget               *gadget;
  68         struct ffs_data                 *ffs;
  69
  70         struct ffs_ep                   *eps;
  71         u8                              eps_revmap[16];
  72         short                           *interfaces_nums;
  73
  74         struct usb_function             function;
  75 };
  76
  77
  78 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  79 {
  80         return container_of(f, struct ffs_function, function);
  81 }
  82
  83
  84 static inline enum ffs_setup_state
  85 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  86 {
  87         return (enum ffs_setup_state)
  88                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  89 }
  90
  91
  92 static void ffs_func_eps_disable(struct ffs_function *func);
  93 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  94
  95 static int ffs_func_bind(struct usb_configuration *,
  96                          struct usb_function *);
  97 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
  98 static void ffs_func_disable(struct usb_function *);
  99 static int ffs_func_setup(struct usb_function *,
 100                           const struct usb_ctrlrequest *);
 101 static void ffs_func_suspend(struct usb_function *);
 102 static void ffs_func_resume(struct usb_function *);
 103
 104
 105 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 106 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 107
 108
 109 /* The endpoints structures *************************************************/
 110
 111 struct ffs_ep {
 112         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 113         struct usb_request              *req;   /* P: epfile->mutex */
 114
 115         /* [0]: full speed, [1]: high speed, [2]: super speed */
 116         struct usb_endpoint_descriptor  *descs[3];
 117
 118         u8                              num;
 119
 120         int                             status; /* P: epfile->mutex */
 121 };
 122
 123 struct ffs_epfile {
 124         /* Protects ep->ep and ep->req. */
 125         struct mutex                    mutex;
 126         wait_queue_head_t               wait;
 127
 128         struct ffs_data                 *ffs;
 129         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 130
 131         struct dentry                   *dentry;
 132
 133         char                            name[5];
 134
 135         unsigned char                   in;     /* P: ffs->eps_lock */
 136         unsigned char                   isoc;   /* P: ffs->eps_lock */
 137
 138         unsigned char                   _pad;
 139 };
 140
 141 /*  ffs_io_data structure ***************************************************/
 142
 143 struct ffs_io_data {
 144         bool aio;
 145         bool read;
 146
 147         struct kiocb *kiocb;
 148         struct iov_iter data;
 149         const void *to_free;
 150         char *buf;
 151
 152         struct mm_struct *mm;
 153         struct work_struct work;
 154
 155         struct usb_ep *ep;
 156         struct usb_request *req;
 157
 158         struct ffs_data *ffs;
 159 };
 160
 161 struct ffs_desc_helper {
 162         struct ffs_data *ffs;
 163         unsigned interfaces_count;
 164         unsigned eps_count;
 165 };
 166
 167 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 168 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 169
 170 static struct dentry *
 171 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 172                    const struct file_operations *fops);
 173
 174 /* Devices management *******************************************************/
 175
 176 DEFINE_MUTEX(ffs_lock);
 177 EXPORT_SYMBOL_GPL(ffs_lock);
 178
 179 static struct ffs_dev *_ffs_find_dev(const char *name);
 180 static struct ffs_dev *_ffs_alloc_dev(void);
 181 static int _ffs_name_dev(struct ffs_dev *dev, const char *name);
 182 static void _ffs_free_dev(struct ffs_dev *dev);
 183 static void *ffs_acquire_dev(const char *dev_name);
 184 static void ffs_release_dev(struct ffs_data *ffs_data);
 185 static int ffs_ready(struct ffs_data *ffs);
 186 static void ffs_closed(struct ffs_data *ffs);
 187
 188 /* Misc helper functions ****************************************************/
 189
 190 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 191         __attribute__((warn_unused_result, nonnull));
 192 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 193         __attribute__((warn_unused_result, nonnull));
 194
 195
 196 /* Control file aka ep0 *****************************************************/
 197
 198 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 199 {
 200         struct ffs_data *ffs = req->context;
 201
 202         complete_all(&ffs->ep0req_completion);
 203 }
 204
 205 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 206 {
 207         struct usb_request *req = ffs->ep0req;
 208         int ret;
 209
 210         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 211
 212         spin_unlock_irq(&ffs->ev.waitq.lock);
 213
 214         req->buf      = data;
 215         req->length   = len;
 216
 217         /*
 218          * UDC layer requires to provide a buffer even for ZLP, but should
 219          * not use it at all. Let's provide some poisoned pointer to catch
 220          * possible bug in the driver.
 221          */
 222         if (req->buf == NULL)
 223                 req->buf = (void *)0xDEADBABE;
 224
 225         reinit_completion(&ffs->ep0req_completion);
 226
 227         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 228         if (unlikely(ret < 0))
 229                 return ret;
 230
 231         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 232         if (unlikely(ret)) {
 233                 usb_ep_dequeue(ffs->gadget->ep0, req);
 234                 return -EINTR;
 235         }
 236
 237         ffs->setup_state = FFS_NO_SETUP;
 238         return req->status ? req->status : req->actual;
 239 }
 240
 241 static int __ffs_ep0_stall(struct ffs_data *ffs)
 242 {
 243         if (ffs->ev.can_stall) {
 244                 pr_vdebug("ep0 stall\n");
 245                 usb_ep_set_halt(ffs->gadget->ep0);
 246                 ffs->setup_state = FFS_NO_SETUP;
 247                 return -EL2HLT;
 248         } else {
 249                 pr_debug("bogus ep0 stall!\n");
 250                 return -ESRCH;
 251         }
 252 }
 253
 254 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 255                              size_t len, loff_t *ptr)
 256 {
 257         struct ffs_data *ffs = file->private_data;
 258         ssize_t ret;
 259         char *data;
 260
 261         ENTER();
 262
 263         /* Fast check if setup was canceled */
 264         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 265                 return -EIDRM;
 266
 267         /* Acquire mutex */
 268         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 269         if (unlikely(ret < 0))
 270                 return ret;
 271
 272         /* Check state */
 273         switch (ffs->state) {
 274         case FFS_READ_DESCRIPTORS:
 275         case FFS_READ_STRINGS:
 276                 /* Copy data */
 277                 if (unlikely(len < 16)) {
 278                         ret = -EINVAL;
 279                         break;
 280                 }
 281
 282                 data = ffs_prepare_buffer(buf, len);
 283                 if (IS_ERR(data)) {
 284                         ret = PTR_ERR(data);
 285                         break;
 286                 }
 287
 288                 /* Handle data */
 289                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 290                         pr_info("read descriptors\n");
 291                         ret = __ffs_data_got_descs(ffs, data, len);
 292                         if (unlikely(ret < 0))
 293                                 break;
 294
 295                         ffs->state = FFS_READ_STRINGS;
 296                         ret = len;
 297                 } else {
 298                         pr_info("read strings\n");
 299                         ret = __ffs_data_got_strings(ffs, data, len);
 300                         if (unlikely(ret < 0))
 301                                 break;
 302
 303                         ret = ffs_epfiles_create(ffs);
 304                         if (unlikely(ret)) {
 305                                 ffs->state = FFS_CLOSING;
 306                                 break;
 307                         }
 308
 309                         ffs->state = FFS_ACTIVE;
 310                         mutex_unlock(&ffs->mutex);
 311
 312                         ret = ffs_ready(ffs);
 313                         if (unlikely(ret < 0)) {
 314                                 ffs->state = FFS_CLOSING;
 315                                 return ret;
 316                         }
 317
 318                         return len;
 319                 }
 320                 break;
 321
 322         case FFS_ACTIVE:
 323                 data = NULL;
 324                 /*
 325                  * We're called from user space, we can use _irq
 326                  * rather then _irqsave
 327                  */
 328                 spin_lock_irq(&ffs->ev.waitq.lock);
 329                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 330                 case FFS_SETUP_CANCELLED:
 331                         ret = -EIDRM;
 332                         goto done_spin;
 333
 334                 case FFS_NO_SETUP:
 335                         ret = -ESRCH;
 336                         goto done_spin;
 337
 338                 case FFS_SETUP_PENDING:
 339                         break;
 340                 }
 341
 342                 /* FFS_SETUP_PENDING */
 343                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 344                         spin_unlock_irq(&ffs->ev.waitq.lock);
 345                         ret = __ffs_ep0_stall(ffs);
 346                         break;
 347                 }
 348
 349                 /* FFS_SETUP_PENDING and not stall */
 350                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 351
 352                 spin_unlock_irq(&ffs->ev.waitq.lock);
 353
 354                 data = ffs_prepare_buffer(buf, len);
 355                 if (IS_ERR(data)) {
 356                         ret = PTR_ERR(data);
 357                         break;
 358                 }
 359
 360                 spin_lock_irq(&ffs->ev.waitq.lock);
 361
 362                 /*
 363                  * We are guaranteed to be still in FFS_ACTIVE state
 364                  * but the state of setup could have changed from
 365                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 366                  * to check for that.  If that happened we copied data
 367                  * from user space in vain but it's unlikely.
 368                  *
 369                  * For sure we are not in FFS_NO_SETUP since this is
 370                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 371                  * transition can be performed and it's protected by
 372                  * mutex.
 373                  */
 374                 if (ffs_setup_state_clear_cancelled(ffs) ==
 375                     FFS_SETUP_CANCELLED) {
 376                         ret = -EIDRM;
 377 done_spin:
 378                         spin_unlock_irq(&ffs->ev.waitq.lock);
 379                 } else {
 380                         /* unlocks spinlock */
 381                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 382                 }
 383                 kfree(data);
 384                 break;
 385
 386         default:
 387                 ret = -EBADFD;
 388                 break;
 389         }
 390
 391         mutex_unlock(&ffs->mutex);
 392         return ret;
 393 }
 394
 395 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 396 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 397                                      size_t n)
 398 {
 399         /*
 400          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 401          * size of ffs->ev.types array (which is four) so that's how much space
 402          * we reserve.
 403          */
 404         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 405         const size_t size = n * sizeof *events;
 406         unsigned i = 0;
 407
 408         memset(events, 0, size);
 409
 410         do {
 411                 events[i].type = ffs->ev.types[i];
 412                 if (events[i].type == FUNCTIONFS_SETUP) {
 413                         events[i].u.setup = ffs->ev.setup;
 414                         ffs->setup_state = FFS_SETUP_PENDING;
 415                 }
 416         } while (++i < n);
 417
 418         ffs->ev.count -= n;
 419         if (ffs->ev.count)
 420                 memmove(ffs->ev.types, ffs->ev.types + n,
 421                         ffs->ev.count * sizeof *ffs->ev.types);
 422
 423         spin_unlock_irq(&ffs->ev.waitq.lock);
 424         mutex_unlock(&ffs->mutex);
 425
 426         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 427 }
 428
 429 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 430                             size_t len, loff_t *ptr)
 431 {
 432         struct ffs_data *ffs = file->private_data;
 433         char *data = NULL;
 434         size_t n;
 435         int ret;
 436
 437         ENTER();
 438
 439         /* Fast check if setup was canceled */
 440         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 441                 return -EIDRM;
 442
 443         /* Acquire mutex */
 444         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 445         if (unlikely(ret < 0))
 446                 return ret;
 447
 448         /* Check state */
 449         if (ffs->state != FFS_ACTIVE) {
 450                 ret = -EBADFD;
 451                 goto done_mutex;
 452         }
 453
 454         /*
 455          * We're called from user space, we can use _irq rather then
 456          * _irqsave
 457          */
 458         spin_lock_irq(&ffs->ev.waitq.lock);
 459
 460         switch (ffs_setup_state_clear_cancelled(ffs)) {
 461         case FFS_SETUP_CANCELLED:
 462                 ret = -EIDRM;
 463                 break;
 464
 465         case FFS_NO_SETUP:
 466                 n = len / sizeof(struct usb_functionfs_event);
 467                 if (unlikely(!n)) {
 468                         ret = -EINVAL;
 469                         break;
 470                 }
 471
 472                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 473                         ret = -EAGAIN;
 474                         break;
 475                 }
 476
 477                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 478                                                         ffs->ev.count)) {
 479                         ret = -EINTR;
 480                         break;
 481                 }
 482
 483                 return __ffs_ep0_read_events(ffs, buf,
 484                                              min(n, (size_t)ffs->ev.count));
 485
 486         case FFS_SETUP_PENDING:
 487                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 488                         spin_unlock_irq(&ffs->ev.waitq.lock);
 489                         ret = __ffs_ep0_stall(ffs);
 490                         goto done_mutex;
 491                 }
 492
 493                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 494
 495                 spin_unlock_irq(&ffs->ev.waitq.lock);
 496
 497                 if (likely(len)) {
 498                         data = kmalloc(len, GFP_KERNEL);
 499                         if (unlikely(!data)) {
 500                                 ret = -ENOMEM;
 501                                 goto done_mutex;
 502                         }
 503                 }
 504
 505                 spin_lock_irq(&ffs->ev.waitq.lock);
 506
 507                 /* See ffs_ep0_write() */
 508                 if (ffs_setup_state_clear_cancelled(ffs) ==
 509                     FFS_SETUP_CANCELLED) {
 510                         ret = -EIDRM;
 511                         break;
 512                 }
 513
 514                 /* unlocks spinlock */
 515                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 516                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 517                         ret = -EFAULT;
 518                 goto done_mutex;
 519
 520         default:
 521                 ret = -EBADFD;
 522                 break;
 523         }
 524
 525         spin_unlock_irq(&ffs->ev.waitq.lock);
 526 done_mutex:
 527         mutex_unlock(&ffs->mutex);
 528         kfree(data);
 529         return ret;
 530 }
 531
 532 static int ffs_ep0_open(struct inode *inode, struct file *file)
 533 {
 534         struct ffs_data *ffs = inode->i_private;
 535
 536         ENTER();
 537
 538         if (unlikely(ffs->state == FFS_CLOSING))
 539                 return -EBUSY;
 540
 541         file->private_data = ffs;
 542         ffs_data_opened(ffs);
 543
 544         return 0;
 545 }
 546
 547 static int ffs_ep0_release(struct inode *inode, struct file *file)
 548 {
 549         struct ffs_data *ffs = file->private_data;
 550
 551         ENTER();
 552
 553         ffs_data_closed(ffs);
 554
 555         return 0;
 556 }
 557
 558 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 559 {
 560         struct ffs_data *ffs = file->private_data;
 561         struct usb_gadget *gadget = ffs->gadget;
 562         long ret;
 563
 564         ENTER();
 565
 566         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 567                 struct ffs_function *func = ffs->func;
 568                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 569         } else if (gadget && gadget->ops->ioctl) {
 570                 ret = gadget->ops->ioctl(gadget, code, value);
 571         } else {
 572                 ret = -ENOTTY;
 573         }
 574
 575         return ret;
 576 }
 577
 578 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
 579 {
 580         struct ffs_data *ffs = file->private_data;
 581         unsigned int mask = POLLWRNORM;
 582         int ret;
 583
 584         poll_wait(file, &ffs->ev.waitq, wait);
 585
 586         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 587         if (unlikely(ret < 0))
 588                 return mask;
 589
 590         switch (ffs->state) {
 591         case FFS_READ_DESCRIPTORS:
 592         case FFS_READ_STRINGS:
 593                 mask |= POLLOUT;
 594                 break;
 595
 596         case FFS_ACTIVE:
 597                 switch (ffs->setup_state) {
 598                 case FFS_NO_SETUP:
 599                         if (ffs->ev.count)
 600                                 mask |= POLLIN;
 601                         break;
 602
 603                 case FFS_SETUP_PENDING:
 604                 case FFS_SETUP_CANCELLED:
 605                         mask |= (POLLIN | POLLOUT);
 606                         break;
 607                 }
 608         case FFS_CLOSING:
 609                 break;
 610         case FFS_DEACTIVATED:
 611                 break;
 612         }
 613
 614         mutex_unlock(&ffs->mutex);
 615
 616         return mask;
 617 }
 618
 619 static const struct file_operations ffs_ep0_operations = {
 620         .llseek =       no_llseek,
 621
 622         .open =         ffs_ep0_open,
 623         .write =        ffs_ep0_write,
 624         .read =         ffs_ep0_read,
 625         .release =      ffs_ep0_release,
 626         .unlocked_ioctl =       ffs_ep0_ioctl,
 627         .poll =         ffs_ep0_poll,
 628 };
 629
 630
 631 /* "Normal" endpoints operations ********************************************/
 632
 633 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 634 {
 635         ENTER();
 636         if (likely(req->context)) {
 637                 struct ffs_ep *ep = _ep->driver_data;
 638                 ep->status = req->status ? req->status : req->actual;
 639                 complete(req->context);
 640         }
 641 }
 642
 643 static void ffs_user_copy_worker(struct work_struct *work)
 644 {
 645         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 646                                                    work);
 647         int ret = io_data->req->status ? io_data->req->status :
 648                                          io_data->req->actual;
 649         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 650
 651         if (io_data->read && ret > 0) {
 652                 use_mm(io_data->mm);
 653                 ret = copy_to_iter(io_data->buf, ret, &io_data->data);
 654                 if (ret != io_data->req->actual && iov_iter_count(&io_data->data))
 655                         ret = -EFAULT;
 656                 unuse_mm(io_data->mm);
 657         }
 658
 659         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 660
 661         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 662                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 663
 664         usb_ep_free_request(io_data->ep, io_data->req);
 665
 666         if (io_data->read)
 667                 kfree(io_data->to_free);
 668         kfree(io_data->buf);
 669         kfree(io_data);
 670 }
 671
 672 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 673                                          struct usb_request *req)
 674 {
 675         struct ffs_io_data *io_data = req->context;
 676
 677         ENTER();
 678
 679         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 680         schedule_work(&io_data->work);
 681 }
 682
 683 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 684 {
 685         struct ffs_epfile *epfile = file->private_data;
 686         struct ffs_ep *ep;
 687         char *data = NULL;
 688         ssize_t ret, data_len = -EINVAL;
 689         int halt;
 690
 691         /* Are we still active? */
 692         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
 693                 ret = -ENODEV;
 694                 goto error;
 695         }
 696
 697         /* Wait for endpoint to be enabled */
 698         ep = epfile->ep;
 699         if (!ep) {
 700                 if (file->f_flags & O_NONBLOCK) {
 701                         ret = -EAGAIN;
 702                         goto error;
 703                 }
 704
 705                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
 706                 if (ret) {
 707                         ret = -EINTR;
 708                         goto error;
 709                 }
 710         }
 711
 712         /* Do we halt? */
 713         halt = (!io_data->read == !epfile->in);
 714         if (halt && epfile->isoc) {
 715                 ret = -EINVAL;
 716                 goto error;
 717         }
 718
 719         /* Allocate & copy */
 720         if (!halt) {
 721                 /*
 722                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 723                  * before the waiting completes, so do not assign to 'gadget' earlier
 724                  */
 725                 struct usb_gadget *gadget = epfile->ffs->gadget;
 726                 size_t copied;
 727
 728                 spin_lock_irq(&epfile->ffs->eps_lock);
 729                 /* In the meantime, endpoint got disabled or changed. */
 730                 if (epfile->ep != ep) {
 731                         spin_unlock_irq(&epfile->ffs->eps_lock);
 732                         return -ESHUTDOWN;
 733                 }
 734                 data_len = iov_iter_count(&io_data->data);
 735                 /*
 736                  * Controller may require buffer size to be aligned to
 737                  * maxpacketsize of an out endpoint.
 738                  */
 739                 if (io_data->read)
 740                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
 741                 spin_unlock_irq(&epfile->ffs->eps_lock);
 742
 743                 data = kmalloc(data_len, GFP_KERNEL);
 744                 if (unlikely(!data))
 745                         return -ENOMEM;
 746                 if (!io_data->read) {
 747                         copied = copy_from_iter(data, data_len, &io_data->data);
 748                         if (copied != data_len) {
 749                                 ret = -EFAULT;
 750                                 goto error;
 751                         }
 752                 }
 753         }
 754
 755         /* We will be using request */
 756         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 757         if (unlikely(ret))
 758                 goto error;
 759
 760         spin_lock_irq(&epfile->ffs->eps_lock);
 761
 762         if (epfile->ep != ep) {
 763                 /* In the meantime, endpoint got disabled or changed. */
 764                 ret = -ESHUTDOWN;
 765                 spin_unlock_irq(&epfile->ffs->eps_lock);
 766         } else if (halt) {
 767                 /* Halt */
 768                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 769                         usb_ep_set_halt(ep->ep);
 770                 spin_unlock_irq(&epfile->ffs->eps_lock);
 771                 ret = -EBADMSG;
 772         } else {
 773                 /* Fire the request */
 774                 struct usb_request *req;
 775
 776                 /*
 777                  * Sanity Check: even though data_len can't be used
 778                  * uninitialized at the time I write this comment, some
 779                  * compilers complain about this situation.
 780                  * In order to keep the code clean from warnings, data_len is
 781                  * being initialized to -EINVAL during its declaration, which
 782                  * means we can't rely on compiler anymore to warn no future
 783                  * changes won't result in data_len being used uninitialized.
 784                  * For such reason, we're adding this redundant sanity check
 785                  * here.
 786                  */
 787                 if (unlikely(data_len == -EINVAL)) {
 788                         WARN(1, "%s: data_len == -EINVAL\n", __func__);
 789                         ret = -EINVAL;
 790                         goto error_lock;
 791                 }
 792
 793                 if (io_data->aio) {
 794                         req = usb_ep_alloc_request(ep->ep, GFP_KERNEL);
 795                         if (unlikely(!req))
 796                                 goto error_lock;
 797
 798                         req->buf      = data;
 799                         req->length   = data_len;
 800
 801                         io_data->buf = data;
 802                         io_data->ep = ep->ep;
 803                         io_data->req = req;
 804                         io_data->ffs = epfile->ffs;
 805
 806                         req->context  = io_data;
 807                         req->complete = ffs_epfile_async_io_complete;
 808
 809                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 810                         if (unlikely(ret)) {
 811                                 usb_ep_free_request(ep->ep, req);
 812                                 goto error_lock;
 813                         }
 814                         ret = -EIOCBQUEUED;
 815
 816                         spin_unlock_irq(&epfile->ffs->eps_lock);
 817                 } else {
 818                         DECLARE_COMPLETION_ONSTACK(done);
 819
 820                         req = ep->req;
 821                         req->buf      = data;
 822                         req->length   = data_len;
 823
 824                         req->context  = &done;
 825                         req->complete = ffs_epfile_io_complete;
 826
 827                         ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 828
 829                         spin_unlock_irq(&epfile->ffs->eps_lock);
 830
 831                         if (unlikely(ret < 0)) {
 832                                 /* nop */
 833                         } else if (unlikely(
 834                                    wait_for_completion_interruptible(&done))) {
 835                                 ret = -EINTR;
 836                                 usb_ep_dequeue(ep->ep, req);
 837                         } else {
 838                                 /*
 839                                  * XXX We may end up silently droping data
 840                                  * here.  Since data_len (i.e. req->length) may
 841                                  * be bigger than len (after being rounded up
 842                                  * to maxpacketsize), we may end up with more
 843                                  * data then user space has space for.
 844                                  */
 845                                 ret = ep->status;
 846                                 if (io_data->read && ret > 0) {
 847                                         ret = copy_to_iter(data, ret, &io_data->data);
 848                                         if (!ret)
 849                                                 ret = -EFAULT;
 850                                 }
 851                         }
 852                         kfree(data);
 853                 }
 854         }
 855
 856         mutex_unlock(&epfile->mutex);
 857         return ret;
 858
 859 error_lock:
 860         spin_unlock_irq(&epfile->ffs->eps_lock);
 861         mutex_unlock(&epfile->mutex);
 862 error:
 863         kfree(data);
 864         return ret;
 865 }
 866
 867 static int
 868 ffs_epfile_open(struct inode *inode, struct file *file)
 869 {
 870         struct ffs_epfile *epfile = inode->i_private;
 871
 872         ENTER();
 873
 874         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 875                 return -ENODEV;
 876
 877         file->private_data = epfile;
 878         ffs_data_opened(epfile->ffs);
 879
 880         return 0;
 881 }
 882
 883 static int ffs_aio_cancel(struct kiocb *kiocb)
 884 {
 885         struct ffs_io_data *io_data = kiocb->private;
 886         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
 887         int value;
 888
 889         ENTER();
 890
 891         spin_lock_irq(&epfile->ffs->eps_lock);
 892
 893         if (likely(io_data && io_data->ep && io_data->req))
 894                 value = usb_ep_dequeue(io_data->ep, io_data->req);
 895         else
 896                 value = -EINVAL;
 897
 898         spin_unlock_irq(&epfile->ffs->eps_lock);
 899
 900         return value;
 901 }
 902
 903 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
 904 {
 905         struct ffs_io_data io_data, *p = &io_data;
 906         ssize_t res;
 907
 908         ENTER();
 909
 910         if (!is_sync_kiocb(kiocb)) {
 911                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
 912                 if (unlikely(!p))
 913                         return -ENOMEM;
 914                 p->aio = true;
 915         } else {
 916                 p->aio = false;
 917         }
 918
 919         p->read = false;
 920         p->kiocb = kiocb;
 921         p->data = *from;
 922         p->mm = current->mm;
 923
 924         kiocb->private = p;
 925
 926         if (p->aio)
 927                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 928
 929         res = ffs_epfile_io(kiocb->ki_filp, p);
 930         if (res == -EIOCBQUEUED)
 931                 return res;
 932         if (p->aio)
 933                 kfree(p);
 934         else
 935                 *from = p->data;
 936         return res;
 937 }
 938
 939 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
 940 {
 941         struct ffs_io_data io_data, *p = &io_data;
 942         ssize_t res;
 943
 944         ENTER();
 945
 946         if (!is_sync_kiocb(kiocb)) {
 947                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
 948                 if (unlikely(!p))
 949                         return -ENOMEM;
 950                 p->aio = true;
 951         } else {
 952                 p->aio = false;
 953         }
 954
 955         p->read = true;
 956         p->kiocb = kiocb;
 957         if (p->aio) {
 958                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
 959                 if (!p->to_free) {
 960                         kfree(p);
 961                         return -ENOMEM;
 962                 }
 963         } else {
 964                 p->data = *to;
 965                 p->to_free = NULL;
 966         }
 967         p->mm = current->mm;
 968
 969         kiocb->private = p;
 970
 971         if (p->aio)
 972                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
 973
 974         res = ffs_epfile_io(kiocb->ki_filp, p);
 975         if (res == -EIOCBQUEUED)
 976                 return res;
 977
 978         if (p->aio) {
 979                 kfree(p->to_free);
 980                 kfree(p);
 981         } else {
 982                 *to = p->data;
 983         }
 984         return res;
 985 }
 986
 987 static int
 988 ffs_epfile_release(struct inode *inode, struct file *file)
 989 {
 990         struct ffs_epfile *epfile = inode->i_private;
 991
 992         ENTER();
 993
 994         ffs_data_closed(epfile->ffs);
 995
 996         return 0;
 997 }
 998
 999 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1000                              unsigned long value)
1001 {
1002         struct ffs_epfile *epfile = file->private_data;
1003         int ret;
1004
1005         ENTER();
1006
1007         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1008                 return -ENODEV;
1009
1010         spin_lock_irq(&epfile->ffs->eps_lock);
1011         if (likely(epfile->ep)) {
1012                 switch (code) {
1013                 case FUNCTIONFS_FIFO_STATUS:
1014                         ret = usb_ep_fifo_status(epfile->ep->ep);
1015                         break;
1016                 case FUNCTIONFS_FIFO_FLUSH:
1017                         usb_ep_fifo_flush(epfile->ep->ep);
1018                         ret = 0;
1019                         break;
1020                 case FUNCTIONFS_CLEAR_HALT:
1021                         ret = usb_ep_clear_halt(epfile->ep->ep);
1022                         break;
1023                 case FUNCTIONFS_ENDPOINT_REVMAP:
1024                         ret = epfile->ep->num;
1025                         break;
1026                 case FUNCTIONFS_ENDPOINT_DESC:
1027                 {
1028                         int desc_idx;
1029                         struct usb_endpoint_descriptor *desc;
1030
1031                         switch (epfile->ffs->gadget->speed) {
1032                         case USB_SPEED_SUPER:
1033                                 desc_idx = 2;
1034                                 break;
1035                         case USB_SPEED_HIGH:
1036                                 desc_idx = 1;
1037                                 break;
1038                         default:
1039                                 desc_idx = 0;
1040                         }
1041                         desc = epfile->ep->descs[desc_idx];
1042
1043                         spin_unlock_irq(&epfile->ffs->eps_lock);
1044                         ret = copy_to_user((void *)value, desc, sizeof(*desc));
1045                         if (ret)
1046                                 ret = -EFAULT;
1047                         return ret;
1048                 }
1049                 default:
1050                         ret = -ENOTTY;
1051                 }
1052         } else {
1053                 ret = -ENODEV;
1054         }
1055         spin_unlock_irq(&epfile->ffs->eps_lock);
1056
1057         return ret;
1058 }
1059
1060 static const struct file_operations ffs_epfile_operations = {
1061         .llseek =       no_llseek,
1062
1063         .open =         ffs_epfile_open,
1064         .write_iter =   ffs_epfile_write_iter,
1065         .read_iter =    ffs_epfile_read_iter,
1066         .release =      ffs_epfile_release,
1067         .unlocked_ioctl =       ffs_epfile_ioctl,
1068 };
1069
1070
1071 /* File system and super block operations ***********************************/
1072
1073 /*
1074  * Mounting the file system creates a controller file, used first for
1075  * function configuration then later for event monitoring.
1076  */
1077
1078 static struct inode *__must_check
1079 ffs_sb_make_inode(struct super_block *sb, void *data,
1080                   const struct file_operations *fops,
1081                   const struct inode_operations *iops,
1082                   struct ffs_file_perms *perms)
1083 {
1084         struct inode *inode;
1085
1086         ENTER();
1087
1088         inode = new_inode(sb);
1089
1090         if (likely(inode)) {
1091                 struct timespec current_time = CURRENT_TIME;
1092
1093                 inode->i_ino     = get_next_ino();
1094                 inode->i_mode    = perms->mode;
1095                 inode->i_uid     = perms->uid;
1096                 inode->i_gid     = perms->gid;
1097                 inode->i_atime   = current_time;
1098                 inode->i_mtime   = current_time;
1099                 inode->i_ctime   = current_time;
1100                 inode->i_private = data;
1101                 if (fops)
1102                         inode->i_fop = fops;
1103                 if (iops)
1104                         inode->i_op  = iops;
1105         }
1106
1107         return inode;
1108 }
1109
1110 /* Create "regular" file */
1111 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1112                                         const char *name, void *data,
1113                                         const struct file_operations *fops)
1114 {
1115         struct ffs_data *ffs = sb->s_fs_info;
1116         struct dentry   *dentry;
1117         struct inode    *inode;
1118
1119         ENTER();
1120
1121         dentry = d_alloc_name(sb->s_root, name);
1122         if (unlikely(!dentry))
1123                 return NULL;
1124
1125         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1126         if (unlikely(!inode)) {
1127                 dput(dentry);
1128                 return NULL;
1129         }
1130
1131         d_add(dentry, inode);
1132         return dentry;
1133 }
1134
1135 /* Super block */
1136 static const struct super_operations ffs_sb_operations = {
1137         .statfs =       simple_statfs,
1138         .drop_inode =   generic_delete_inode,
1139 };
1140
1141 struct ffs_sb_fill_data {
1142         struct ffs_file_perms perms;
1143         umode_t root_mode;
1144         const char *dev_name;
1145         bool no_disconnect;
1146         struct ffs_data *ffs_data;
1147 };
1148
1149 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1150 {
1151         struct ffs_sb_fill_data *data = _data;
1152         struct inode    *inode;
1153         struct ffs_data *ffs = data->ffs_data;
1154
1155         ENTER();
1156
1157         ffs->sb              = sb;
1158         data->ffs_data       = NULL;
1159         sb->s_fs_info        = ffs;
1160         sb->s_blocksize      = PAGE_CACHE_SIZE;
1161         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1162         sb->s_magic          = FUNCTIONFS_MAGIC;
1163         sb->s_op             = &ffs_sb_operations;
1164         sb->s_time_gran      = 1;
1165
1166         /* Root inode */
1167         data->perms.mode = data->root_mode;
1168         inode = ffs_sb_make_inode(sb, NULL,
1169                                   &simple_dir_operations,
1170                                   &simple_dir_inode_operations,
1171                                   &data->perms);
1172         sb->s_root = d_make_root(inode);
1173         if (unlikely(!sb->s_root))
1174                 return -ENOMEM;
1175
1176         /* EP0 file */
1177         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1178                                          &ffs_ep0_operations)))
1179                 return -ENOMEM;
1180
1181         return 0;
1182 }
1183
1184 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1185 {
1186         ENTER();
1187
1188         if (!opts || !*opts)
1189                 return 0;
1190
1191         for (;;) {
1192                 unsigned long value;
1193                 char *eq, *comma;
1194
1195                 /* Option limit */
1196                 comma = strchr(opts, ',');
1197                 if (comma)
1198                         *comma = 0;
1199
1200                 /* Value limit */
1201                 eq = strchr(opts, '=');
1202                 if (unlikely(!eq)) {
1203                         pr_err("'=' missing in %s\n", opts);
1204                         return -EINVAL;
1205                 }
1206                 *eq = 0;
1207
1208                 /* Parse value */
1209                 if (kstrtoul(eq + 1, 0, &value)) {
1210                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1211                         return -EINVAL;
1212                 }
1213
1214                 /* Interpret option */
1215                 switch (eq - opts) {
1216                 case 13:
1217                         if (!memcmp(opts, "no_disconnect", 13))
1218                                 data->no_disconnect = !!value;
1219                         else
1220                                 goto invalid;
1221                         break;
1222                 case 5:
1223                         if (!memcmp(opts, "rmode", 5))
1224                                 data->root_mode  = (value & 0555) | S_IFDIR;
1225                         else if (!memcmp(opts, "fmode", 5))
1226                                 data->perms.mode = (value & 0666) | S_IFREG;
1227                         else
1228                                 goto invalid;
1229                         break;
1230
1231                 case 4:
1232                         if (!memcmp(opts, "mode", 4)) {
1233                                 data->root_mode  = (value & 0555) | S_IFDIR;
1234                                 data->perms.mode = (value & 0666) | S_IFREG;
1235                         } else {
1236                                 goto invalid;
1237                         }
1238                         break;
1239
1240                 case 3:
1241                         if (!memcmp(opts, "uid", 3)) {
1242                                 data->perms.uid = make_kuid(current_user_ns(), value);
1243                                 if (!uid_valid(data->perms.uid)) {
1244                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1245                                         return -EINVAL;
1246                                 }
1247                         } else if (!memcmp(opts, "gid", 3)) {
1248                                 data->perms.gid = make_kgid(current_user_ns(), value);
1249                                 if (!gid_valid(data->perms.gid)) {
1250                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1251                                         return -EINVAL;
1252                                 }
1253                         } else {
1254                                 goto invalid;
1255                         }
1256                         break;
1257
1258                 default:
1259 invalid:
1260                         pr_err("%s: invalid option\n", opts);
1261                         return -EINVAL;
1262                 }
1263
1264                 /* Next iteration */
1265                 if (!comma)
1266                         break;
1267                 opts = comma + 1;
1268         }
1269
1270         return 0;
1271 }
1272
1273 /* "mount -t functionfs dev_name /dev/function" ends up here */
1274
1275 static struct dentry *
1276 ffs_fs_mount(struct file_system_type *t, int flags,
1277               const char *dev_name, void *opts)
1278 {
1279         struct ffs_sb_fill_data data = {
1280                 .perms = {
1281                         .mode = S_IFREG | 0600,
1282                         .uid = GLOBAL_ROOT_UID,
1283                         .gid = GLOBAL_ROOT_GID,
1284                 },
1285                 .root_mode = S_IFDIR | 0500,
1286                 .no_disconnect = false,
1287         };
1288         struct dentry *rv;
1289         int ret;
1290         void *ffs_dev;
1291         struct ffs_data *ffs;
1292
1293         ENTER();
1294
1295         ret = ffs_fs_parse_opts(&data, opts);
1296         if (unlikely(ret < 0))
1297                 return ERR_PTR(ret);
1298
1299         ffs = ffs_data_new();
1300         if (unlikely(!ffs))
1301                 return ERR_PTR(-ENOMEM);
1302         ffs->file_perms = data.perms;
1303         ffs->no_disconnect = data.no_disconnect;
1304
1305         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1306         if (unlikely(!ffs->dev_name)) {
1307                 ffs_data_put(ffs);
1308                 return ERR_PTR(-ENOMEM);
1309         }
1310
1311         ffs_dev = ffs_acquire_dev(dev_name);
1312         if (IS_ERR(ffs_dev)) {
1313                 ffs_data_put(ffs);
1314                 return ERR_CAST(ffs_dev);
1315         }
1316         ffs->private_data = ffs_dev;
1317         data.ffs_data = ffs;
1318
1319         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1320         if (IS_ERR(rv) && data.ffs_data) {
1321                 ffs_release_dev(data.ffs_data);
1322                 ffs_data_put(data.ffs_data);
1323         }
1324         return rv;
1325 }
1326
1327 static void
1328 ffs_fs_kill_sb(struct super_block *sb)
1329 {
1330         ENTER();
1331
1332         kill_litter_super(sb);
1333         if (sb->s_fs_info) {
1334                 ffs_release_dev(sb->s_fs_info);
1335                 ffs_data_closed(sb->s_fs_info);
1336                 ffs_data_put(sb->s_fs_info);
1337         }
1338 }
1339
1340 static struct file_system_type ffs_fs_type = {
1341         .owner          = THIS_MODULE,
1342         .name           = "functionfs",
1343         .mount          = ffs_fs_mount,
1344         .kill_sb        = ffs_fs_kill_sb,
1345 };
1346 MODULE_ALIAS_FS("functionfs");
1347
1348
1349 /* Driver's main init/cleanup functions *************************************/
1350
1351 static int functionfs_init(void)
1352 {
1353         int ret;
1354
1355         ENTER();
1356
1357         ret = register_filesystem(&ffs_fs_type);
1358         if (likely(!ret))
1359                 pr_info("file system registered\n");
1360         else
1361                 pr_err("failed registering file system (%d)\n", ret);
1362
1363         return ret;
1364 }
1365
1366 static void functionfs_cleanup(void)
1367 {
1368         ENTER();
1369
1370         pr_info("unloading\n");
1371         unregister_filesystem(&ffs_fs_type);
1372 }
1373
1374
1375 /* ffs_data and ffs_function construction and destruction code **************/
1376
1377 static void ffs_data_clear(struct ffs_data *ffs);
1378 static void ffs_data_reset(struct ffs_data *ffs);
1379
1380 static void ffs_data_get(struct ffs_data *ffs)
1381 {
1382         ENTER();
1383
1384         atomic_inc(&ffs->ref);
1385 }
1386
1387 static void ffs_data_opened(struct ffs_data *ffs)
1388 {
1389         ENTER();
1390
1391         atomic_inc(&ffs->ref);
1392         if (atomic_add_return(1, &ffs->opened) == 1 &&
1393                         ffs->state == FFS_DEACTIVATED) {
1394                 ffs->state = FFS_CLOSING;
1395                 ffs_data_reset(ffs);
1396         }
1397 }
1398
1399 static void ffs_data_put(struct ffs_data *ffs)
1400 {
1401         ENTER();
1402
1403         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1404                 pr_info("%s(): freeing\n", __func__);
1405                 ffs_data_clear(ffs);
1406                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1407                        waitqueue_active(&ffs->ep0req_completion.wait));
1408                 kfree(ffs->dev_name);
1409                 kfree(ffs);
1410         }
1411 }
1412
1413 static void ffs_data_closed(struct ffs_data *ffs)
1414 {
1415         ENTER();
1416
1417         if (atomic_dec_and_test(&ffs->opened)) {
1418                 if (ffs->no_disconnect) {
1419                         ffs->state = FFS_DEACTIVATED;
1420                         if (ffs->epfiles) {
1421                                 ffs_epfiles_destroy(ffs->epfiles,
1422                                                    ffs->eps_count);
1423                                 ffs->epfiles = NULL;
1424                         }
1425                         if (ffs->setup_state == FFS_SETUP_PENDING)
1426                                 __ffs_ep0_stall(ffs);
1427                 } else {
1428                         ffs->state = FFS_CLOSING;
1429                         ffs_data_reset(ffs);
1430                 }
1431         }
1432         if (atomic_read(&ffs->opened) < 0) {
1433                 ffs->state = FFS_CLOSING;
1434                 ffs_data_reset(ffs);
1435         }
1436
1437         ffs_data_put(ffs);
1438 }
1439
1440 static struct ffs_data *ffs_data_new(void)
1441 {
1442         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1443         if (unlikely(!ffs))
1444                 return NULL;
1445
1446         ENTER();
1447
1448         atomic_set(&ffs->ref, 1);
1449         atomic_set(&ffs->opened, 0);
1450         ffs->state = FFS_READ_DESCRIPTORS;
1451         mutex_init(&ffs->mutex);
1452         spin_lock_init(&ffs->eps_lock);
1453         init_waitqueue_head(&ffs->ev.waitq);
1454         init_completion(&ffs->ep0req_completion);
1455
1456         /* XXX REVISIT need to update it in some places, or do we? */
1457         ffs->ev.can_stall = 1;
1458
1459         return ffs;
1460 }
1461
1462 static void ffs_data_clear(struct ffs_data *ffs)
1463 {
1464         ENTER();
1465
1466         ffs_closed(ffs);
1467
1468         BUG_ON(ffs->gadget);
1469
1470         if (ffs->epfiles)
1471                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1472
1473         if (ffs->ffs_eventfd)
1474                 eventfd_ctx_put(ffs->ffs_eventfd);
1475
1476         kfree(ffs->raw_descs_data);
1477         kfree(ffs->raw_strings);
1478         kfree(ffs->stringtabs);
1479 }
1480
1481 static void ffs_data_reset(struct ffs_data *ffs)
1482 {
1483         ENTER();
1484
1485         ffs_data_clear(ffs);
1486
1487         ffs->epfiles = NULL;
1488         ffs->raw_descs_data = NULL;
1489         ffs->raw_descs = NULL;
1490         ffs->raw_strings = NULL;
1491         ffs->stringtabs = NULL;
1492
1493         ffs->raw_descs_length = 0;
1494         ffs->fs_descs_count = 0;
1495         ffs->hs_descs_count = 0;
1496         ffs->ss_descs_count = 0;
1497
1498         ffs->strings_count = 0;
1499         ffs->interfaces_count = 0;
1500         ffs->eps_count = 0;
1501
1502         ffs->ev.count = 0;
1503
1504         ffs->state = FFS_READ_DESCRIPTORS;
1505         ffs->setup_state = FFS_NO_SETUP;
1506         ffs->flags = 0;
1507 }
1508
1509
1510 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1511 {
1512         struct usb_gadget_strings **lang;
1513         int first_id;
1514
1515         ENTER();
1516
1517         if (WARN_ON(ffs->state != FFS_ACTIVE
1518                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1519                 return -EBADFD;
1520
1521         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1522         if (unlikely(first_id < 0))
1523                 return first_id;
1524
1525         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1526         if (unlikely(!ffs->ep0req))
1527                 return -ENOMEM;
1528         ffs->ep0req->complete = ffs_ep0_complete;
1529         ffs->ep0req->context = ffs;
1530
1531         lang = ffs->stringtabs;
1532         if (lang) {
1533                 for (; *lang; ++lang) {
1534                         struct usb_string *str = (*lang)->strings;
1535                         int id = first_id;
1536                         for (; str->s; ++id, ++str)
1537                                 str->id = id;
1538                 }
1539         }
1540
1541         ffs->gadget = cdev->gadget;
1542         ffs_data_get(ffs);
1543         return 0;
1544 }
1545
1546 static void functionfs_unbind(struct ffs_data *ffs)
1547 {
1548         ENTER();
1549
1550         if (!WARN_ON(!ffs->gadget)) {
1551                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1552                 ffs->ep0req = NULL;
1553                 ffs->gadget = NULL;
1554                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1555                 ffs_data_put(ffs);
1556         }
1557 }
1558
1559 static int ffs_epfiles_create(struct ffs_data *ffs)
1560 {
1561         struct ffs_epfile *epfile, *epfiles;
1562         unsigned i, count;
1563
1564         ENTER();
1565
1566         count = ffs->eps_count;
1567         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1568         if (!epfiles)
1569                 return -ENOMEM;
1570
1571         epfile = epfiles;
1572         for (i = 1; i <= count; ++i, ++epfile) {
1573                 epfile->ffs = ffs;
1574                 mutex_init(&epfile->mutex);
1575                 init_waitqueue_head(&epfile->wait);
1576                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1577                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1578                 else
1579                         sprintf(epfile->name, "ep%u", i);
1580                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1581                                                  epfile,
1582                                                  &ffs_epfile_operations);
1583                 if (unlikely(!epfile->dentry)) {
1584                         ffs_epfiles_destroy(epfiles, i - 1);
1585                         return -ENOMEM;
1586                 }
1587         }
1588
1589         ffs->epfiles = epfiles;
1590         return 0;
1591 }
1592
1593 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1594 {
1595         struct ffs_epfile *epfile = epfiles;
1596
1597         ENTER();
1598
1599         for (; count; --count, ++epfile) {
1600                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1601                        waitqueue_active(&epfile->wait));
1602                 if (epfile->dentry) {
1603                         d_delete(epfile->dentry);
1604                         dput(epfile->dentry);
1605                         epfile->dentry = NULL;
1606                 }
1607         }
1608
1609         kfree(epfiles);
1610 }
1611
1612 static void ffs_func_eps_disable(struct ffs_function *func)
1613 {
1614         struct ffs_ep *ep         = func->eps;
1615         struct ffs_epfile *epfile = func->ffs->epfiles;
1616         unsigned count            = func->ffs->eps_count;
1617         unsigned long flags;
1618
1619         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1620         do {
1621                 /* pending requests get nuked */
1622                 if (likely(ep->ep))
1623                         usb_ep_disable(ep->ep);
1624                 ++ep;
1625
1626                 if (epfile) {
1627                         epfile->ep = NULL;
1628                         ++epfile;
1629                 }
1630         } while (--count);
1631         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1632 }
1633
1634 static int ffs_func_eps_enable(struct ffs_function *func)
1635 {
1636         struct ffs_data *ffs      = func->ffs;
1637         struct ffs_ep *ep         = func->eps;
1638         struct ffs_epfile *epfile = ffs->epfiles;
1639         unsigned count            = ffs->eps_count;
1640         unsigned long flags;
1641         int ret = 0;
1642
1643         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1644         do {
1645                 struct usb_endpoint_descriptor *ds;
1646                 struct usb_ss_ep_comp_descriptor *comp_desc = NULL;
1647                 int needs_comp_desc = false;
1648                 int desc_idx;
1649
1650                 if (ffs->gadget->speed == USB_SPEED_SUPER) {
1651                         desc_idx = 2;
1652                         needs_comp_desc = true;
1653                 } else if (ffs->gadget->speed == USB_SPEED_HIGH)
1654                         desc_idx = 1;
1655                 else
1656                         desc_idx = 0;
1657
1658                 /* fall-back to lower speed if desc missing for current speed */
1659                 do {
1660                         ds = ep->descs[desc_idx];
1661                 } while (!ds && --desc_idx >= 0);
1662
1663                 if (!ds) {
1664                         ret = -EINVAL;
1665                         break;
1666                 }
1667
1668                 ep->ep->driver_data = ep;
1669                 ep->ep->desc = ds;
1670
1671                 comp_desc = (struct usb_ss_ep_comp_descriptor *)(ds +
1672                                 USB_DT_ENDPOINT_SIZE);
1673                 ep->ep->maxburst = comp_desc->bMaxBurst + 1;
1674
1675                 if (needs_comp_desc)
1676                         ep->ep->comp_desc = comp_desc;
1677
1678                 ret = usb_ep_enable(ep->ep);
1679                 if (likely(!ret)) {
1680                         epfile->ep = ep;
1681                         epfile->in = usb_endpoint_dir_in(ds);
1682                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1683                 } else {
1684                         break;
1685                 }
1686
1687                 wake_up(&epfile->wait);
1688
1689                 ++ep;
1690                 ++epfile;
1691         } while (--count);
1692         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1693
1694         return ret;
1695 }
1696
1697
1698 /* Parsing and building descriptors and strings *****************************/
1699
1700 /*
1701  * This validates if data pointed by data is a valid USB descriptor as
1702  * well as record how many interfaces, endpoints and strings are
1703  * required by given configuration.  Returns address after the
1704  * descriptor or NULL if data is invalid.
1705  */
1706
1707 enum ffs_entity_type {
1708         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1709 };
1710
1711 enum ffs_os_desc_type {
1712         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1713 };
1714
1715 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1716                                    u8 *valuep,
1717                                    struct usb_descriptor_header *desc,
1718                                    void *priv);
1719
1720 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1721                                     struct usb_os_desc_header *h, void *data,
1722                                     unsigned len, void *priv);
1723
1724 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1725                                            ffs_entity_callback entity,
1726                                            void *priv)
1727 {
1728         struct usb_descriptor_header *_ds = (void *)data;
1729         u8 length;
1730         int ret;
1731
1732         ENTER();
1733
1734         /* At least two bytes are required: length and type */
1735         if (len < 2) {
1736                 pr_vdebug("descriptor too short\n");
1737                 return -EINVAL;
1738         }
1739
1740         /* If we have at least as many bytes as the descriptor takes? */
1741         length = _ds->bLength;
1742         if (len < length) {
1743                 pr_vdebug("descriptor longer then available data\n");
1744                 return -EINVAL;
1745         }
1746
1747 #define __entity_check_INTERFACE(val)  1
1748 #define __entity_check_STRING(val)     (val)
1749 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1750 #define __entity(type, val) do {                                        \
1751                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1752                 if (unlikely(!__entity_check_ ##type(val))) {           \
1753                         pr_vdebug("invalid entity's value\n");          \
1754                         return -EINVAL;                                 \
1755                 }                                                       \
1756                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1757                 if (unlikely(ret < 0)) {                                \
1758                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1759                                  (val), ret);                           \
1760                         return ret;                                     \
1761                 }                                                       \
1762         } while (0)
1763
1764         /* Parse descriptor depending on type. */
1765         switch (_ds->bDescriptorType) {
1766         case USB_DT_DEVICE:
1767         case USB_DT_CONFIG:
1768         case USB_DT_STRING:
1769         case USB_DT_DEVICE_QUALIFIER:
1770                 /* function can't have any of those */
1771                 pr_vdebug("descriptor reserved for gadget: %d\n",
1772                       _ds->bDescriptorType);
1773                 return -EINVAL;
1774
1775         case USB_DT_INTERFACE: {
1776                 struct usb_interface_descriptor *ds = (void *)_ds;
1777                 pr_vdebug("interface descriptor\n");
1778                 if (length != sizeof *ds)
1779                         goto inv_length;
1780
1781                 __entity(INTERFACE, ds->bInterfaceNumber);
1782                 if (ds->iInterface)
1783                         __entity(STRING, ds->iInterface);
1784         }
1785                 break;
1786
1787         case USB_DT_ENDPOINT: {
1788                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1789                 pr_vdebug("endpoint descriptor\n");
1790                 if (length != USB_DT_ENDPOINT_SIZE &&
1791                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1792                         goto inv_length;
1793                 __entity(ENDPOINT, ds->bEndpointAddress);
1794         }
1795                 break;
1796
1797         case HID_DT_HID:
1798                 pr_vdebug("hid descriptor\n");
1799                 if (length != sizeof(struct hid_descriptor))
1800                         goto inv_length;
1801                 break;
1802
1803         case USB_DT_OTG:
1804                 if (length != sizeof(struct usb_otg_descriptor))
1805                         goto inv_length;
1806                 break;
1807
1808         case USB_DT_INTERFACE_ASSOCIATION: {
1809                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1810                 pr_vdebug("interface association descriptor\n");
1811                 if (length != sizeof *ds)
1812                         goto inv_length;
1813                 if (ds->iFunction)
1814                         __entity(STRING, ds->iFunction);
1815         }
1816                 break;
1817
1818         case USB_DT_SS_ENDPOINT_COMP:
1819                 pr_vdebug("EP SS companion descriptor\n");
1820                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
1821                         goto inv_length;
1822                 break;
1823
1824         case USB_DT_OTHER_SPEED_CONFIG:
1825         case USB_DT_INTERFACE_POWER:
1826         case USB_DT_DEBUG:
1827         case USB_DT_SECURITY:
1828         case USB_DT_CS_RADIO_CONTROL:
1829                 /* TODO */
1830                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1831                 return -EINVAL;
1832
1833         default:
1834                 /* We should never be here */
1835                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1836                 return -EINVAL;
1837
1838 inv_length:
1839                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1840                           _ds->bLength, _ds->bDescriptorType);
1841                 return -EINVAL;
1842         }
1843
1844 #undef __entity
1845 #undef __entity_check_DESCRIPTOR
1846 #undef __entity_check_INTERFACE
1847 #undef __entity_check_STRING
1848 #undef __entity_check_ENDPOINT
1849
1850         return length;
1851 }
1852
1853 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1854                                      ffs_entity_callback entity, void *priv)
1855 {
1856         const unsigned _len = len;
1857         unsigned long num = 0;
1858
1859         ENTER();
1860
1861         for (;;) {
1862                 int ret;
1863
1864                 if (num == count)
1865                         data = NULL;
1866
1867                 /* Record "descriptor" entity */
1868                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1869                 if (unlikely(ret < 0)) {
1870                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1871                                  num, ret);
1872                         return ret;
1873                 }
1874
1875                 if (!data)
1876                         return _len - len;
1877
1878                 ret = ffs_do_single_desc(data, len, entity, priv);
1879                 if (unlikely(ret < 0)) {
1880                         pr_debug("%s returns %d\n", __func__, ret);
1881                         return ret;
1882                 }
1883
1884                 len -= ret;
1885                 data += ret;
1886                 ++num;
1887         }
1888 }
1889
1890 static int __ffs_data_do_entity(enum ffs_entity_type type,
1891                                 u8 *valuep, struct usb_descriptor_header *desc,
1892                                 void *priv)
1893 {
1894         struct ffs_desc_helper *helper = priv;
1895         struct usb_endpoint_descriptor *d;
1896
1897         ENTER();
1898
1899         switch (type) {
1900         case FFS_DESCRIPTOR:
1901                 break;
1902
1903         case FFS_INTERFACE:
1904                 /*
1905                  * Interfaces are indexed from zero so if we
1906                  * encountered interface "n" then there are at least
1907                  * "n+1" interfaces.
1908                  */
1909                 if (*valuep >= helper->interfaces_count)
1910                         helper->interfaces_count = *valuep + 1;
1911                 break;
1912
1913         case FFS_STRING:
1914                 /*
1915                  * Strings are indexed from 1 (0 is magic ;) reserved
1916                  * for languages list or some such)
1917                  */
1918                 if (*valuep > helper->ffs->strings_count)
1919                         helper->ffs->strings_count = *valuep;
1920                 break;
1921
1922         case FFS_ENDPOINT:
1923                 d = (void *)desc;
1924                 helper->eps_count++;
1925                 if (helper->eps_count >= 15)
1926                         return -EINVAL;
1927                 /* Check if descriptors for any speed were already parsed */
1928                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
1929                         helper->ffs->eps_addrmap[helper->eps_count] =
1930                                 d->bEndpointAddress;
1931                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
1932                                 d->bEndpointAddress)
1933                         return -EINVAL;
1934                 break;
1935         }
1936
1937         return 0;
1938 }
1939
1940 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
1941                                    struct usb_os_desc_header *desc)
1942 {
1943         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
1944         u16 w_index = le16_to_cpu(desc->wIndex);
1945
1946         if (bcd_version != 1) {
1947                 pr_vdebug("unsupported os descriptors version: %d",
1948                           bcd_version);
1949                 return -EINVAL;
1950         }
1951         switch (w_index) {
1952         case 0x4:
1953                 *next_type = FFS_OS_DESC_EXT_COMPAT;
1954                 break;
1955         case 0x5:
1956                 *next_type = FFS_OS_DESC_EXT_PROP;
1957                 break;
1958         default:
1959                 pr_vdebug("unsupported os descriptor type: %d", w_index);
1960                 return -EINVAL;
1961         }
1962
1963         return sizeof(*desc);
1964 }
1965
1966 /*
1967  * Process all extended compatibility/extended property descriptors
1968  * of a feature descriptor
1969  */
1970 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
1971                                               enum ffs_os_desc_type type,
1972                                               u16 feature_count,
1973                                               ffs_os_desc_callback entity,
1974                                               void *priv,
1975                                               struct usb_os_desc_header *h)
1976 {
1977         int ret;
1978         const unsigned _len = len;
1979
1980         ENTER();
1981
1982         /* loop over all ext compat/ext prop descriptors */
1983         while (feature_count--) {
1984                 ret = entity(type, h, data, len, priv);
1985                 if (unlikely(ret < 0)) {
1986                         pr_debug("bad OS descriptor, type: %d\n", type);
1987                         return ret;
1988                 }
1989                 data += ret;
1990                 len -= ret;
1991         }
1992         return _len - len;
1993 }
1994
1995 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
1996 static int __must_check ffs_do_os_descs(unsigned count,
1997                                         char *data, unsigned len,
1998                                         ffs_os_desc_callback entity, void *priv)
1999 {
2000         const unsigned _len = len;
2001         unsigned long num = 0;
2002
2003         ENTER();
2004
2005         for (num = 0; num < count; ++num) {
2006                 int ret;
2007                 enum ffs_os_desc_type type;
2008                 u16 feature_count;
2009                 struct usb_os_desc_header *desc = (void *)data;
2010
2011                 if (len < sizeof(*desc))
2012                         return -EINVAL;
2013
2014                 /*
2015                  * Record "descriptor" entity.
2016                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2017                  * Move the data pointer to the beginning of extended
2018                  * compatibilities proper or extended properties proper
2019                  * portions of the data
2020                  */
2021                 if (le32_to_cpu(desc->dwLength) > len)
2022                         return -EINVAL;
2023
2024                 ret = __ffs_do_os_desc_header(&type, desc);
2025                 if (unlikely(ret < 0)) {
2026                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2027                                  num, ret);
2028                         return ret;
2029                 }
2030                 /*
2031                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2032                  */
2033                 feature_count = le16_to_cpu(desc->wCount);
2034                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2035                     (feature_count > 255 || desc->Reserved))
2036                                 return -EINVAL;
2037                 len -= ret;
2038                 data += ret;
2039
2040                 /*
2041                  * Process all function/property descriptors
2042                  * of this Feature Descriptor
2043                  */
2044                 ret = ffs_do_single_os_desc(data, len, type,
2045                                             feature_count, entity, priv, desc);
2046                 if (unlikely(ret < 0)) {
2047                         pr_debug("%s returns %d\n", __func__, ret);
2048                         return ret;
2049                 }
2050
2051                 len -= ret;
2052                 data += ret;
2053         }
2054         return _len - len;
2055 }
2056
2057 /**
2058  * Validate contents of the buffer from userspace related to OS descriptors.
2059  */
2060 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2061                                  struct usb_os_desc_header *h, void *data,
2062                                  unsigned len, void *priv)
2063 {
2064         struct ffs_data *ffs = priv;
2065         u8 length;
2066
2067         ENTER();
2068
2069         switch (type) {
2070         case FFS_OS_DESC_EXT_COMPAT: {
2071                 struct usb_ext_compat_desc *d = data;
2072                 int i;
2073
2074                 if (len < sizeof(*d) ||
2075                     d->bFirstInterfaceNumber >= ffs->interfaces_count ||
2076                     d->Reserved1)
2077                         return -EINVAL;
2078                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2079                         if (d->Reserved2[i])
2080                                 return -EINVAL;
2081
2082                 length = sizeof(struct usb_ext_compat_desc);
2083         }
2084                 break;
2085         case FFS_OS_DESC_EXT_PROP: {
2086                 struct usb_ext_prop_desc *d = data;
2087                 u32 type, pdl;
2088                 u16 pnl;
2089
2090                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2091                         return -EINVAL;
2092                 length = le32_to_cpu(d->dwSize);
2093                 if (len < length)
2094                         return -EINVAL;
2095                 type = le32_to_cpu(d->dwPropertyDataType);
2096                 if (type < USB_EXT_PROP_UNICODE ||
2097                     type > USB_EXT_PROP_UNICODE_MULTI) {
2098                         pr_vdebug("unsupported os descriptor property type: %d",
2099                                   type);
2100                         return -EINVAL;
2101                 }
2102                 pnl = le16_to_cpu(d->wPropertyNameLength);
2103                 if (length < 14 + pnl) {
2104                         pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n",
2105                                   length, pnl, type);
2106                         return -EINVAL;
2107                 }
2108                 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2109                 if (length != 14 + pnl + pdl) {
2110                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2111                                   length, pnl, pdl, type);
2112                         return -EINVAL;
2113                 }
2114                 ++ffs->ms_os_descs_ext_prop_count;
2115                 /* property name reported to the host as "WCHAR"s */
2116                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2117                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2118         }
2119                 break;
2120         default:
2121                 pr_vdebug("unknown descriptor: %d\n", type);
2122                 return -EINVAL;
2123         }
2124         return length;
2125 }
2126
2127 static int __ffs_data_got_descs(struct ffs_data *ffs,
2128                                 char *const _data, size_t len)
2129 {
2130         char *data = _data, *raw_descs;
2131         unsigned os_descs_count = 0, counts[3], flags;
2132         int ret = -EINVAL, i;
2133         struct ffs_desc_helper helper;
2134
2135         ENTER();
2136
2137         if (get_unaligned_le32(data + 4) != len)
2138                 goto error;
2139
2140         switch (get_unaligned_le32(data)) {
2141         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2142                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2143                 data += 8;
2144                 len  -= 8;
2145                 break;
2146         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2147                 flags = get_unaligned_le32(data + 8);
2148                 ffs->user_flags = flags;
2149                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2150                               FUNCTIONFS_HAS_HS_DESC |
2151                               FUNCTIONFS_HAS_SS_DESC |
2152                               FUNCTIONFS_HAS_MS_OS_DESC |
2153                               FUNCTIONFS_VIRTUAL_ADDR |
2154                               FUNCTIONFS_EVENTFD)) {
2155                         ret = -ENOSYS;
2156                         goto error;
2157                 }
2158                 data += 12;
2159                 len  -= 12;
2160                 break;
2161         default:
2162                 goto error;
2163         }
2164
2165         if (flags & FUNCTIONFS_EVENTFD) {
2166                 if (len < 4)
2167                         goto error;
2168                 ffs->ffs_eventfd =
2169                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2170                 if (IS_ERR(ffs->ffs_eventfd)) {
2171                         ret = PTR_ERR(ffs->ffs_eventfd);
2172                         ffs->ffs_eventfd = NULL;
2173                         goto error;
2174                 }
2175                 data += 4;
2176                 len  -= 4;
2177         }
2178
2179         /* Read fs_count, hs_count and ss_count (if present) */
2180         for (i = 0; i < 3; ++i) {
2181                 if (!(flags & (1 << i))) {
2182                         counts[i] = 0;
2183                 } else if (len < 4) {
2184                         goto error;
2185                 } else {
2186                         counts[i] = get_unaligned_le32(data);
2187                         data += 4;
2188                         len  -= 4;
2189                 }
2190         }
2191         if (flags & (1 << i)) {
2192                 if (len < 4) {
2193                         goto error;
2194                 }
2195                 os_descs_count = get_unaligned_le32(data);
2196                 data += 4;
2197                 len -= 4;
2198         };
2199
2200         /* Read descriptors */
2201         raw_descs = data;
2202         helper.ffs = ffs;
2203         for (i = 0; i < 3; ++i) {
2204                 if (!counts[i])
2205                         continue;
2206                 helper.interfaces_count = 0;
2207                 helper.eps_count = 0;
2208                 ret = ffs_do_descs(counts[i], data, len,
2209                                    __ffs_data_do_entity, &helper);
2210                 if (ret < 0)
2211                         goto error;
2212                 if (!ffs->eps_count && !ffs->interfaces_count) {
2213                         ffs->eps_count = helper.eps_count;
2214                         ffs->interfaces_count = helper.interfaces_count;
2215                 } else {
2216                         if (ffs->eps_count != helper.eps_count) {
2217                                 ret = -EINVAL;
2218                                 goto error;
2219                         }
2220                         if (ffs->interfaces_count != helper.interfaces_count) {
2221                                 ret = -EINVAL;
2222                                 goto error;
2223                         }
2224                 }
2225                 data += ret;
2226                 len  -= ret;
2227         }
2228         if (os_descs_count) {
2229                 ret = ffs_do_os_descs(os_descs_count, data, len,
2230                                       __ffs_data_do_os_desc, ffs);
2231                 if (ret < 0)
2232                         goto error;
2233                 data += ret;
2234                 len -= ret;
2235         }
2236
2237         if (raw_descs == data || len) {
2238                 ret = -EINVAL;
2239                 goto error;
2240         }
2241
2242         ffs->raw_descs_data     = _data;
2243         ffs->raw_descs          = raw_descs;
2244         ffs->raw_descs_length   = data - raw_descs;
2245         ffs->fs_descs_count     = counts[0];
2246         ffs->hs_descs_count     = counts[1];
2247         ffs->ss_descs_count     = counts[2];
2248         ffs->ms_os_descs_count  = os_descs_count;
2249
2250         return 0;
2251
2252 error:
2253         kfree(_data);
2254         return ret;
2255 }
2256
2257 static int __ffs_data_got_strings(struct ffs_data *ffs,
2258                                   char *const _data, size_t len)
2259 {
2260         u32 str_count, needed_count, lang_count;
2261         struct usb_gadget_strings **stringtabs, *t;
2262         struct usb_string *strings, *s;
2263         const char *data = _data;
2264
2265         ENTER();
2266
2267         if (unlikely(len < 16 ||
2268                      get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2269                      get_unaligned_le32(data + 4) != len))
2270                 goto error;
2271         str_count  = get_unaligned_le32(data + 8);
2272         lang_count = get_unaligned_le32(data + 12);
2273
2274         /* if one is zero the other must be zero */
2275         if (unlikely(!str_count != !lang_count))
2276                 goto error;
2277
2278         /* Do we have at least as many strings as descriptors need? */
2279         needed_count = ffs->strings_count;
2280         if (unlikely(str_count < needed_count))
2281                 goto error;
2282
2283         /*
2284          * If we don't need any strings just return and free all
2285          * memory.
2286          */
2287         if (!needed_count) {
2288                 kfree(_data);
2289                 return 0;
2290         }
2291
2292         /* Allocate everything in one chunk so there's less maintenance. */
2293         {
2294                 unsigned i = 0;
2295                 vla_group(d);
2296                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2297                         lang_count + 1);
2298                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2299                 vla_item(d, struct usb_string, strings,
2300                         lang_count*(needed_count+1));
2301
2302                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2303
2304                 if (unlikely(!vlabuf)) {
2305                         kfree(_data);
2306                         return -ENOMEM;
2307                 }
2308
2309                 /* Initialize the VLA pointers */
2310                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2311                 t = vla_ptr(vlabuf, d, stringtab);
2312                 i = lang_count;
2313                 do {
2314                         *stringtabs++ = t++;
2315                 } while (--i);
2316                 *stringtabs = NULL;
2317
2318                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2319                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2320                 t = vla_ptr(vlabuf, d, stringtab);
2321                 s = vla_ptr(vlabuf, d, strings);
2322                 strings = s;
2323         }
2324
2325         /* For each language */
2326         data += 16;
2327         len -= 16;
2328
2329         do { /* lang_count > 0 so we can use do-while */
2330                 unsigned needed = needed_count;
2331
2332                 if (unlikely(len < 3))
2333                         goto error_free;
2334                 t->language = get_unaligned_le16(data);
2335                 t->strings  = s;
2336                 ++t;
2337
2338                 data += 2;
2339                 len -= 2;
2340
2341                 /* For each string */
2342                 do { /* str_count > 0 so we can use do-while */
2343                         size_t length = strnlen(data, len);
2344
2345                         if (unlikely(length == len))
2346                                 goto error_free;
2347
2348                         /*
2349                          * User may provide more strings then we need,
2350                          * if that's the case we simply ignore the
2351                          * rest
2352                          */
2353                         if (likely(needed)) {
2354                                 /*
2355                                  * s->id will be set while adding
2356                                  * function to configuration so for
2357                                  * now just leave garbage here.
2358                                  */
2359                                 s->s = data;
2360                                 --needed;
2361                                 ++s;
2362                         }
2363
2364                         data += length + 1;
2365                         len -= length + 1;
2366                 } while (--str_count);
2367
2368                 s->id = 0;   /* terminator */
2369                 s->s = NULL;
2370                 ++s;
2371
2372         } while (--lang_count);
2373
2374         /* Some garbage left? */
2375         if (unlikely(len))
2376                 goto error_free;
2377
2378         /* Done! */
2379         ffs->stringtabs = stringtabs;
2380         ffs->raw_strings = _data;
2381
2382         return 0;
2383
2384 error_free:
2385         kfree(stringtabs);
2386 error:
2387         kfree(_data);
2388         return -EINVAL;
2389 }
2390
2391
2392 /* Events handling and management *******************************************/
2393
2394 static void __ffs_event_add(struct ffs_data *ffs,
2395                             enum usb_functionfs_event_type type)
2396 {
2397         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2398         int neg = 0;
2399
2400         /*
2401          * Abort any unhandled setup
2402          *
2403          * We do not need to worry about some cmpxchg() changing value
2404          * of ffs->setup_state without holding the lock because when
2405          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2406          * the source does nothing.
2407          */
2408         if (ffs->setup_state == FFS_SETUP_PENDING)
2409                 ffs->setup_state = FFS_SETUP_CANCELLED;
2410
2411         /*
2412          * Logic of this function guarantees that there are at most four pending
2413          * evens on ffs->ev.types queue.  This is important because the queue
2414          * has space for four elements only and __ffs_ep0_read_events function
2415          * depends on that limit as well.  If more event types are added, those
2416          * limits have to be revisited or guaranteed to still hold.
2417          */
2418         switch (type) {
2419         case FUNCTIONFS_RESUME:
2420                 rem_type2 = FUNCTIONFS_SUSPEND;
2421                 /* FALL THROUGH */
2422         case FUNCTIONFS_SUSPEND:
2423         case FUNCTIONFS_SETUP:
2424                 rem_type1 = type;
2425                 /* Discard all similar events */
2426                 break;
2427
2428         case FUNCTIONFS_BIND:
2429         case FUNCTIONFS_UNBIND:
2430         case FUNCTIONFS_DISABLE:
2431         case FUNCTIONFS_ENABLE:
2432                 /* Discard everything other then power management. */
2433                 rem_type1 = FUNCTIONFS_SUSPEND;
2434                 rem_type2 = FUNCTIONFS_RESUME;
2435                 neg = 1;
2436                 break;
2437
2438         default:
2439                 WARN(1, "%d: unknown event, this should not happen\n", type);
2440                 return;
2441         }
2442
2443         {
2444                 u8 *ev  = ffs->ev.types, *out = ev;
2445                 unsigned n = ffs->ev.count;
2446                 for (; n; --n, ++ev)
2447                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2448                                 *out++ = *ev;
2449                         else
2450                                 pr_vdebug("purging event %d\n", *ev);
2451                 ffs->ev.count = out - ffs->ev.types;
2452         }
2453
2454         pr_vdebug("adding event %d\n", type);
2455         ffs->ev.types[ffs->ev.count++] = type;
2456         wake_up_locked(&ffs->ev.waitq);
2457         if (ffs->ffs_eventfd)
2458                 eventfd_signal(ffs->ffs_eventfd, 1);
2459 }
2460
2461 static void ffs_event_add(struct ffs_data *ffs,
2462                           enum usb_functionfs_event_type type)
2463 {
2464         unsigned long flags;
2465         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2466         __ffs_event_add(ffs, type);
2467         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2468 }
2469
2470 /* Bind/unbind USB function hooks *******************************************/
2471
2472 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2473 {
2474         int i;
2475
2476         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2477                 if (ffs->eps_addrmap[i] == endpoint_address)
2478                         return i;
2479         return -ENOENT;
2480 }
2481
2482 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2483                                     struct usb_descriptor_header *desc,
2484                                     void *priv)
2485 {
2486         struct usb_endpoint_descriptor *ds = (void *)desc;
2487         struct ffs_function *func = priv;
2488         struct ffs_ep *ffs_ep;
2489         unsigned ep_desc_id;
2490         int idx;
2491         static const char *speed_names[] = { "full", "high", "super" };
2492
2493         if (type != FFS_DESCRIPTOR)
2494                 return 0;
2495
2496         /*
2497          * If ss_descriptors is not NULL, we are reading super speed
2498          * descriptors; if hs_descriptors is not NULL, we are reading high
2499          * speed descriptors; otherwise, we are reading full speed
2500          * descriptors.
2501          */
2502         if (func->function.ss_descriptors) {
2503                 ep_desc_id = 2;
2504                 func->function.ss_descriptors[(long)valuep] = desc;
2505         } else if (func->function.hs_descriptors) {
2506                 ep_desc_id = 1;
2507                 func->function.hs_descriptors[(long)valuep] = desc;
2508         } else {
2509                 ep_desc_id = 0;
2510                 func->function.fs_descriptors[(long)valuep]    = desc;
2511         }
2512
2513         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2514                 return 0;
2515
2516         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2517         if (idx < 0)
2518                 return idx;
2519
2520         ffs_ep = func->eps + idx;
2521
2522         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2523                 pr_err("two %sspeed descriptors for EP %d\n",
2524                           speed_names[ep_desc_id],
2525                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2526                 return -EINVAL;
2527         }
2528         ffs_ep->descs[ep_desc_id] = ds;
2529
2530         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2531         if (ffs_ep->ep) {
2532                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2533                 if (!ds->wMaxPacketSize)
2534                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2535         } else {
2536                 struct usb_request *req;
2537                 struct usb_ep *ep;
2538                 u8 bEndpointAddress;
2539
2540                 /*
2541                  * We back up bEndpointAddress because autoconfig overwrites
2542                  * it with physical endpoint address.
2543                  */
2544                 bEndpointAddress = ds->bEndpointAddress;
2545                 pr_vdebug("autoconfig\n");
2546                 ep = usb_ep_autoconfig(func->gadget, ds);
2547                 if (unlikely(!ep))
2548                         return -ENOTSUPP;
2549                 ep->driver_data = func->eps + idx;
2550
2551                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2552                 if (unlikely(!req))
2553                         return -ENOMEM;
2554
2555                 ffs_ep->ep  = ep;
2556                 ffs_ep->req = req;
2557                 func->eps_revmap[ds->bEndpointAddress &
2558                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2559                 /*
2560                  * If we use virtual address mapping, we restore
2561                  * original bEndpointAddress value.
2562                  */
2563                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2564                         ds->bEndpointAddress = bEndpointAddress;
2565         }
2566         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2567
2568         return 0;
2569 }
2570
2571 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2572                                    struct usb_descriptor_header *desc,
2573                                    void *priv)
2574 {
2575         struct ffs_function *func = priv;
2576         unsigned idx;
2577         u8 newValue;
2578
2579         switch (type) {
2580         default:
2581         case FFS_DESCRIPTOR:
2582                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2583                 return 0;
2584
2585         case FFS_INTERFACE:
2586                 idx = *valuep;
2587                 if (func->interfaces_nums[idx] < 0) {
2588                         int id = usb_interface_id(func->conf, &func->function);
2589                         if (unlikely(id < 0))
2590                                 return id;
2591                         func->interfaces_nums[idx] = id;
2592                 }
2593                 newValue = func->interfaces_nums[idx];
2594                 break;
2595
2596         case FFS_STRING:
2597                 /* String' IDs are allocated when fsf_data is bound to cdev */
2598                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2599                 break;
2600
2601         case FFS_ENDPOINT:
2602                 /*
2603                  * USB_DT_ENDPOINT are handled in
2604                  * __ffs_func_bind_do_descs().
2605                  */
2606                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2607                         return 0;
2608
2609                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2610                 if (unlikely(!func->eps[idx].ep))
2611                         return -EINVAL;
2612
2613                 {
2614                         struct usb_endpoint_descriptor **descs;
2615                         descs = func->eps[idx].descs;
2616                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2617                 }
2618                 break;
2619         }
2620
2621         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2622         *valuep = newValue;
2623         return 0;
2624 }
2625
2626 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2627                                       struct usb_os_desc_header *h, void *data,
2628                                       unsigned len, void *priv)
2629 {
2630         struct ffs_function *func = priv;
2631         u8 length = 0;
2632
2633         switch (type) {
2634         case FFS_OS_DESC_EXT_COMPAT: {
2635                 struct usb_ext_compat_desc *desc = data;
2636                 struct usb_os_desc_table *t;
2637
2638                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2639                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2640                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2641                        ARRAY_SIZE(desc->CompatibleID) +
2642                        ARRAY_SIZE(desc->SubCompatibleID));
2643                 length = sizeof(*desc);
2644         }
2645                 break;
2646         case FFS_OS_DESC_EXT_PROP: {
2647                 struct usb_ext_prop_desc *desc = data;
2648                 struct usb_os_desc_table *t;
2649                 struct usb_os_desc_ext_prop *ext_prop;
2650                 char *ext_prop_name;
2651                 char *ext_prop_data;
2652
2653                 t = &func->function.os_desc_table[h->interface];
2654                 t->if_id = func->interfaces_nums[h->interface];
2655
2656                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2657                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2658
2659                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2660                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2661                 ext_prop->data_len = le32_to_cpu(*(u32 *)
2662                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2663                 length = ext_prop->name_len + ext_prop->data_len + 14;
2664
2665                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2666                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2667                         ext_prop->name_len;
2668
2669                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2670                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2671                         ext_prop->data_len;
2672                 memcpy(ext_prop_data,
2673                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2674                        ext_prop->data_len);
2675                 /* unicode data reported to the host as "WCHAR"s */
2676                 switch (ext_prop->type) {
2677                 case USB_EXT_PROP_UNICODE:
2678                 case USB_EXT_PROP_UNICODE_ENV:
2679                 case USB_EXT_PROP_UNICODE_LINK:
2680                 case USB_EXT_PROP_UNICODE_MULTI:
2681                         ext_prop->data_len *= 2;
2682                         break;
2683                 }
2684                 ext_prop->data = ext_prop_data;
2685
2686                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2687                        ext_prop->name_len);
2688                 /* property name reported to the host as "WCHAR"s */
2689                 ext_prop->name_len *= 2;
2690                 ext_prop->name = ext_prop_name;
2691
2692                 t->os_desc->ext_prop_len +=
2693                         ext_prop->name_len + ext_prop->data_len + 14;
2694                 ++t->os_desc->ext_prop_count;
2695                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2696         }
2697                 break;
2698         default:
2699                 pr_vdebug("unknown descriptor: %d\n", type);
2700         }
2701
2702         return length;
2703 }
2704
2705 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2706                                                 struct usb_configuration *c)
2707 {
2708         struct ffs_function *func = ffs_func_from_usb(f);
2709         struct f_fs_opts *ffs_opts =
2710                 container_of(f->fi, struct f_fs_opts, func_inst);
2711         int ret;
2712
2713         ENTER();
2714
2715         /*
2716          * Legacy gadget triggers binding in functionfs_ready_callback,
2717          * which already uses locking; taking the same lock here would
2718          * cause a deadlock.
2719          *
2720          * Configfs-enabled gadgets however do need ffs_dev_lock.
2721          */
2722         if (!ffs_opts->no_configfs)
2723                 ffs_dev_lock();
2724         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2725         func->ffs = ffs_opts->dev->ffs_data;
2726         if (!ffs_opts->no_configfs)
2727                 ffs_dev_unlock();
2728         if (ret)
2729                 return ERR_PTR(ret);
2730
2731         func->conf = c;
2732         func->gadget = c->cdev->gadget;
2733
2734         /*
2735          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2736          * configurations are bound in sequence with list_for_each_entry,
2737          * in each configuration its functions are bound in sequence
2738          * with list_for_each_entry, so we assume no race condition
2739          * with regard to ffs_opts->bound access
2740          */
2741         if (!ffs_opts->refcnt) {
2742                 ret = functionfs_bind(func->ffs, c->cdev);
2743                 if (ret)
2744                         return ERR_PTR(ret);
2745         }
2746         ffs_opts->refcnt++;
2747         func->function.strings = func->ffs->stringtabs;
2748
2749         return ffs_opts;
2750 }
2751
2752 static int _ffs_func_bind(struct usb_configuration *c,
2753                           struct usb_function *f)
2754 {
2755         struct ffs_function *func = ffs_func_from_usb(f);
2756         struct ffs_data *ffs = func->ffs;
2757
2758         const int full = !!func->ffs->fs_descs_count;
2759         const int high = gadget_is_dualspeed(func->gadget) &&
2760                 func->ffs->hs_descs_count;
2761         const int super = gadget_is_superspeed(func->gadget) &&
2762                 func->ffs->ss_descs_count;
2763
2764         int fs_len, hs_len, ss_len, ret, i;
2765         struct ffs_ep *eps_ptr;
2766
2767         /* Make it a single chunk, less management later on */
2768         vla_group(d);
2769         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2770         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2771                 full ? ffs->fs_descs_count + 1 : 0);
2772         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2773                 high ? ffs->hs_descs_count + 1 : 0);
2774         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2775                 super ? ffs->ss_descs_count + 1 : 0);
2776         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2777         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2778                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2779         vla_item_with_sz(d, char[16], ext_compat,
2780                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2781         vla_item_with_sz(d, struct usb_os_desc, os_desc,
2782                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2783         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2784                          ffs->ms_os_descs_ext_prop_count);
2785         vla_item_with_sz(d, char, ext_prop_name,
2786                          ffs->ms_os_descs_ext_prop_name_len);
2787         vla_item_with_sz(d, char, ext_prop_data,
2788                          ffs->ms_os_descs_ext_prop_data_len);
2789         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2790         char *vlabuf;
2791
2792         ENTER();
2793
2794         /* Has descriptors only for speeds gadget does not support */
2795         if (unlikely(!(full | high | super)))
2796                 return -ENOTSUPP;
2797
2798         /* Allocate a single chunk, less management later on */
2799         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
2800         if (unlikely(!vlabuf))
2801                 return -ENOMEM;
2802
2803         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
2804         ffs->ms_os_descs_ext_prop_name_avail =
2805                 vla_ptr(vlabuf, d, ext_prop_name);
2806         ffs->ms_os_descs_ext_prop_data_avail =
2807                 vla_ptr(vlabuf, d, ext_prop_data);
2808
2809         /* Copy descriptors  */
2810         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2811                ffs->raw_descs_length);
2812
2813         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2814         eps_ptr = vla_ptr(vlabuf, d, eps);
2815         for (i = 0; i < ffs->eps_count; i++)
2816                 eps_ptr[i].num = -1;
2817
2818         /* Save pointers
2819          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2820         */
2821         func->eps             = vla_ptr(vlabuf, d, eps);
2822         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2823
2824         /*
2825          * Go through all the endpoint descriptors and allocate
2826          * endpoints first, so that later we can rewrite the endpoint
2827          * numbers without worrying that it may be described later on.
2828          */
2829         if (likely(full)) {
2830                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
2831                 fs_len = ffs_do_descs(ffs->fs_descs_count,
2832                                       vla_ptr(vlabuf, d, raw_descs),
2833                                       d_raw_descs__sz,
2834                                       __ffs_func_bind_do_descs, func);
2835                 if (unlikely(fs_len < 0)) {
2836                         ret = fs_len;
2837                         goto error;
2838                 }
2839         } else {
2840                 fs_len = 0;
2841         }
2842
2843         if (likely(high)) {
2844                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
2845                 hs_len = ffs_do_descs(ffs->hs_descs_count,
2846                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
2847                                       d_raw_descs__sz - fs_len,
2848                                       __ffs_func_bind_do_descs, func);
2849                 if (unlikely(hs_len < 0)) {
2850                         ret = hs_len;
2851                         goto error;
2852                 }
2853         } else {
2854                 hs_len = 0;
2855         }
2856
2857         if (likely(super)) {
2858                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
2859                 ss_len = ffs_do_descs(ffs->ss_descs_count,
2860                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
2861                                 d_raw_descs__sz - fs_len - hs_len,
2862                                 __ffs_func_bind_do_descs, func);
2863                 if (unlikely(ss_len < 0)) {
2864                         ret = ss_len;
2865                         goto error;
2866                 }
2867         } else {
2868                 ss_len = 0;
2869         }
2870
2871         /*
2872          * Now handle interface numbers allocation and interface and
2873          * endpoint numbers rewriting.  We can do that in one go
2874          * now.
2875          */
2876         ret = ffs_do_descs(ffs->fs_descs_count +
2877                            (high ? ffs->hs_descs_count : 0) +
2878                            (super ? ffs->ss_descs_count : 0),
2879                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
2880                            __ffs_func_bind_do_nums, func);
2881         if (unlikely(ret < 0))
2882                 goto error;
2883
2884         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
2885         if (c->cdev->use_os_string)
2886                 for (i = 0; i < ffs->interfaces_count; ++i) {
2887                         struct usb_os_desc *desc;
2888
2889                         desc = func->function.os_desc_table[i].os_desc =
2890                                 vla_ptr(vlabuf, d, os_desc) +
2891                                 i * sizeof(struct usb_os_desc);
2892                         desc->ext_compat_id =
2893                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
2894                         INIT_LIST_HEAD(&desc->ext_prop);
2895                 }
2896         ret = ffs_do_os_descs(ffs->ms_os_descs_count,
2897                               vla_ptr(vlabuf, d, raw_descs) +
2898                               fs_len + hs_len + ss_len,
2899                               d_raw_descs__sz - fs_len - hs_len - ss_len,
2900                               __ffs_func_bind_do_os_desc, func);
2901         if (unlikely(ret < 0))
2902                 goto error;
2903         func->function.os_desc_n =
2904                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
2905
2906         /* And we're done */
2907         ffs_event_add(ffs, FUNCTIONFS_BIND);
2908         return 0;
2909
2910 error:
2911         /* XXX Do we need to release all claimed endpoints here? */
2912         return ret;
2913 }
2914
2915 static int ffs_func_bind(struct usb_configuration *c,
2916                          struct usb_function *f)
2917 {
2918         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
2919         struct ffs_function *func = ffs_func_from_usb(f);
2920         int ret;
2921
2922         if (IS_ERR(ffs_opts))
2923                 return PTR_ERR(ffs_opts);
2924
2925         ret = _ffs_func_bind(c, f);
2926         if (ret && !--ffs_opts->refcnt)
2927                 functionfs_unbind(func->ffs);
2928
2929         return ret;
2930 }
2931
2932
2933 /* Other USB function hooks *************************************************/
2934
2935 static void ffs_reset_work(struct work_struct *work)
2936 {
2937         struct ffs_data *ffs = container_of(work,
2938                 struct ffs_data, reset_work);
2939         ffs_data_reset(ffs);
2940 }
2941
2942 static int ffs_func_set_alt(struct usb_function *f,
2943                             unsigned interface, unsigned alt)
2944 {
2945         struct ffs_function *func = ffs_func_from_usb(f);
2946         struct ffs_data *ffs = func->ffs;
2947         int ret = 0, intf;
2948
2949         if (alt != (unsigned)-1) {
2950                 intf = ffs_func_revmap_intf(func, interface);
2951                 if (unlikely(intf < 0))
2952                         return intf;
2953         }
2954
2955         if (ffs->func)
2956                 ffs_func_eps_disable(ffs->func);
2957
2958         if (ffs->state == FFS_DEACTIVATED) {
2959                 ffs->state = FFS_CLOSING;
2960                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
2961                 schedule_work(&ffs->reset_work);
2962                 return -ENODEV;
2963         }
2964
2965         if (ffs->state != FFS_ACTIVE)
2966                 return -ENODEV;
2967
2968         if (alt == (unsigned)-1) {
2969                 ffs->func = NULL;
2970                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2971                 return 0;
2972         }
2973
2974         ffs->func = func;
2975         ret = ffs_func_eps_enable(func);
2976         if (likely(ret >= 0))
2977                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2978         return ret;
2979 }
2980
2981 static void ffs_func_disable(struct usb_function *f)
2982 {
2983         ffs_func_set_alt(f, 0, (unsigned)-1);
2984 }
2985
2986 static int ffs_func_setup(struct usb_function *f,
2987                           const struct usb_ctrlrequest *creq)
2988 {
2989         struct ffs_function *func = ffs_func_from_usb(f);
2990         struct ffs_data *ffs = func->ffs;
2991         unsigned long flags;
2992         int ret;
2993
2994         ENTER();
2995
2996         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2997         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2998         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2999         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3000         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3001
3002         /*
3003          * Most requests directed to interface go through here
3004          * (notable exceptions are set/get interface) so we need to
3005          * handle them.  All other either handled by composite or
3006          * passed to usb_configuration->setup() (if one is set).  No
3007          * matter, we will handle requests directed to endpoint here
3008          * as well (as it's straightforward) but what to do with any
3009          * other request?
3010          */
3011         if (ffs->state != FFS_ACTIVE)
3012                 return -ENODEV;
3013
3014         switch (creq->bRequestType & USB_RECIP_MASK) {
3015         case USB_RECIP_INTERFACE:
3016                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3017                 if (unlikely(ret < 0))
3018                         return ret;
3019                 break;
3020
3021         case USB_RECIP_ENDPOINT:
3022                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3023                 if (unlikely(ret < 0))
3024                         return ret;
3025                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3026                         ret = func->ffs->eps_addrmap[ret];
3027                 break;
3028
3029         default:
3030                 return -EOPNOTSUPP;
3031         }
3032
3033         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3034         ffs->ev.setup = *creq;
3035         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3036         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3037         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3038
3039         return 0;
3040 }
3041
3042 static void ffs_func_suspend(struct usb_function *f)
3043 {
3044         ENTER();
3045         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3046 }
3047
3048 static void ffs_func_resume(struct usb_function *f)
3049 {
3050         ENTER();
3051         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3052 }
3053
3054
3055 /* Endpoint and interface numbers reverse mapping ***************************/
3056
3057 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3058 {
3059         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3060         return num ? num : -EDOM;
3061 }
3062
3063 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3064 {
3065         short *nums = func->interfaces_nums;
3066         unsigned count = func->ffs->interfaces_count;
3067
3068         for (; count; --count, ++nums) {
3069                 if (*nums >= 0 && *nums == intf)
3070                         return nums - func->interfaces_nums;
3071         }
3072
3073         return -EDOM;
3074 }
3075
3076
3077 /* Devices management *******************************************************/
3078
3079 static LIST_HEAD(ffs_devices);
3080
3081 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3082 {
3083         struct ffs_dev *dev;
3084
3085         list_for_each_entry(dev, &ffs_devices, entry) {
3086                 if (!dev->name || !name)
3087                         continue;
3088                 if (strcmp(dev->name, name) == 0)
3089                         return dev;
3090         }
3091
3092         return NULL;
3093 }
3094
3095 /*
3096  * ffs_lock must be taken by the caller of this function
3097  */
3098 static struct ffs_dev *_ffs_get_single_dev(void)
3099 {
3100         struct ffs_dev *dev;
3101
3102         if (list_is_singular(&ffs_devices)) {
3103                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3104                 if (dev->single)
3105                         return dev;
3106         }
3107
3108         return NULL;
3109 }
3110
3111 /*
3112  * ffs_lock must be taken by the caller of this function
3113  */
3114 static struct ffs_dev *_ffs_find_dev(const char *name)
3115 {
3116         struct ffs_dev *dev;
3117
3118         dev = _ffs_get_single_dev();
3119         if (dev)
3120                 return dev;
3121
3122         return _ffs_do_find_dev(name);
3123 }
3124
3125 /* Configfs support *********************************************************/
3126
3127 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3128 {
3129         return container_of(to_config_group(item), struct f_fs_opts,
3130                             func_inst.group);
3131 }
3132
3133 static void ffs_attr_release(struct config_item *item)
3134 {
3135         struct f_fs_opts *opts = to_ffs_opts(item);
3136
3137         usb_put_function_instance(&opts->func_inst);
3138 }
3139
3140 static struct configfs_item_operations ffs_item_ops = {
3141         .release        = ffs_attr_release,
3142 };
3143
3144 static struct config_item_type ffs_func_type = {
3145         .ct_item_ops    = &ffs_item_ops,
3146         .ct_owner       = THIS_MODULE,
3147 };
3148
3149
3150 /* Function registration interface ******************************************/
3151
3152 static void ffs_free_inst(struct usb_function_instance *f)
3153 {
3154         struct f_fs_opts *opts;
3155
3156         opts = to_f_fs_opts(f);
3157         ffs_dev_lock();
3158         _ffs_free_dev(opts->dev);
3159         ffs_dev_unlock();
3160         kfree(opts);
3161 }
3162
3163 #define MAX_INST_NAME_LEN       40
3164
3165 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3166 {
3167         struct f_fs_opts *opts;
3168         char *ptr;
3169         const char *tmp;
3170         int name_len, ret;
3171
3172         name_len = strlen(name) + 1;
3173         if (name_len > MAX_INST_NAME_LEN)
3174                 return -ENAMETOOLONG;
3175
3176         ptr = kstrndup(name, name_len, GFP_KERNEL);
3177         if (!ptr)
3178                 return -ENOMEM;
3179
3180         opts = to_f_fs_opts(fi);
3181         tmp = NULL;
3182
3183         ffs_dev_lock();
3184
3185         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
3186         ret = _ffs_name_dev(opts->dev, ptr);
3187         if (ret) {
3188                 kfree(ptr);
3189                 ffs_dev_unlock();
3190                 return ret;
3191         }
3192         opts->dev->name_allocated = true;
3193
3194         ffs_dev_unlock();
3195
3196         kfree(tmp);
3197
3198         return 0;
3199 }
3200
3201 static struct usb_function_instance *ffs_alloc_inst(void)
3202 {
3203         struct f_fs_opts *opts;
3204         struct ffs_dev *dev;
3205
3206         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3207         if (!opts)
3208                 return ERR_PTR(-ENOMEM);
3209
3210         opts->func_inst.set_inst_name = ffs_set_inst_name;
3211         opts->func_inst.free_func_inst = ffs_free_inst;
3212         ffs_dev_lock();
3213         dev = _ffs_alloc_dev();
3214         ffs_dev_unlock();
3215         if (IS_ERR(dev)) {
3216                 kfree(opts);
3217                 return ERR_CAST(dev);
3218         }
3219         opts->dev = dev;
3220         dev->opts = opts;
3221
3222         config_group_init_type_name(&opts->func_inst.group, "",
3223                                     &ffs_func_type);
3224         return &opts->func_inst;
3225 }
3226
3227 static void ffs_free(struct usb_function *f)
3228 {
3229         kfree(ffs_func_from_usb(f));
3230 }
3231
3232 static void ffs_func_unbind(struct usb_configuration *c,
3233                             struct usb_function *f)
3234 {
3235         struct ffs_function *func = ffs_func_from_usb(f);
3236         struct ffs_data *ffs = func->ffs;
3237         struct f_fs_opts *opts =
3238                 container_of(f->fi, struct f_fs_opts, func_inst);
3239         struct ffs_ep *ep = func->eps;
3240         unsigned count = ffs->eps_count;
3241         unsigned long flags;
3242
3243         ENTER();
3244         if (ffs->func == func) {
3245                 ffs_func_eps_disable(func);
3246                 ffs->func = NULL;
3247         }
3248
3249         if (!--opts->refcnt)
3250                 functionfs_unbind(ffs);
3251
3252         /* cleanup after autoconfig */
3253         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3254         do {
3255                 if (ep->ep && ep->req)
3256                         usb_ep_free_request(ep->ep, ep->req);
3257                 ep->req = NULL;
3258                 ++ep;
3259         } while (--count);
3260         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3261         kfree(func->eps);
3262         func->eps = NULL;
3263         /*
3264          * eps, descriptors and interfaces_nums are allocated in the
3265          * same chunk so only one free is required.
3266          */
3267         func->function.fs_descriptors = NULL;
3268         func->function.hs_descriptors = NULL;
3269         func->function.ss_descriptors = NULL;
3270         func->interfaces_nums = NULL;
3271
3272         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3273 }
3274
3275 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3276 {
3277         struct ffs_function *func;
3278
3279         ENTER();
3280
3281         func = kzalloc(sizeof(*func), GFP_KERNEL);
3282         if (unlikely(!func))
3283                 return ERR_PTR(-ENOMEM);
3284
3285         func->function.name    = "Function FS Gadget";
3286
3287         func->function.bind    = ffs_func_bind;
3288         func->function.unbind  = ffs_func_unbind;
3289         func->function.set_alt = ffs_func_set_alt;
3290         func->function.disable = ffs_func_disable;
3291         func->function.setup   = ffs_func_setup;
3292         func->function.suspend = ffs_func_suspend;
3293         func->function.resume  = ffs_func_resume;
3294         func->function.free_func = ffs_free;
3295
3296         return &func->function;
3297 }
3298
3299 /*
3300  * ffs_lock must be taken by the caller of this function
3301  */
3302 static struct ffs_dev *_ffs_alloc_dev(void)
3303 {
3304         struct ffs_dev *dev;
3305         int ret;
3306
3307         if (_ffs_get_single_dev())
3308                         return ERR_PTR(-EBUSY);
3309
3310         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3311         if (!dev)
3312                 return ERR_PTR(-ENOMEM);
3313
3314         if (list_empty(&ffs_devices)) {
3315                 ret = functionfs_init();
3316                 if (ret) {
3317                         kfree(dev);
3318                         return ERR_PTR(ret);
3319                 }
3320         }
3321
3322         list_add(&dev->entry, &ffs_devices);
3323
3324         return dev;
3325 }
3326
3327 /*
3328  * ffs_lock must be taken by the caller of this function
3329  * The caller is responsible for "name" being available whenever f_fs needs it
3330  */
3331 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
3332 {
3333         struct ffs_dev *existing;
3334
3335         existing = _ffs_do_find_dev(name);
3336         if (existing)
3337                 return -EBUSY;
3338
3339         dev->name = name;
3340
3341         return 0;
3342 }
3343
3344 /*
3345  * The caller is responsible for "name" being available whenever f_fs needs it
3346  */
3347 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3348 {
3349         int ret;
3350
3351         ffs_dev_lock();
3352         ret = _ffs_name_dev(dev, name);
3353         ffs_dev_unlock();
3354
3355         return ret;
3356 }
3357 EXPORT_SYMBOL_GPL(ffs_name_dev);
3358
3359 int ffs_single_dev(struct ffs_dev *dev)
3360 {
3361         int ret;
3362
3363         ret = 0;
3364         ffs_dev_lock();
3365
3366         if (!list_is_singular(&ffs_devices))
3367                 ret = -EBUSY;
3368         else
3369                 dev->single = true;
3370
3371         ffs_dev_unlock();
3372         return ret;
3373 }
3374 EXPORT_SYMBOL_GPL(ffs_single_dev);
3375
3376 /*
3377  * ffs_lock must be taken by the caller of this function
3378  */
3379 static void _ffs_free_dev(struct ffs_dev *dev)
3380 {
3381         list_del(&dev->entry);
3382         if (dev->name_allocated)
3383                 kfree(dev->name);
3384         kfree(dev);
3385         if (list_empty(&ffs_devices))
3386                 functionfs_cleanup();
3387 }
3388
3389 static void *ffs_acquire_dev(const char *dev_name)
3390 {
3391         struct ffs_dev *ffs_dev;
3392
3393         ENTER();
3394         ffs_dev_lock();
3395
3396         ffs_dev = _ffs_find_dev(dev_name);
3397         if (!ffs_dev)
3398                 ffs_dev = ERR_PTR(-ENOENT);
3399         else if (ffs_dev->mounted)
3400                 ffs_dev = ERR_PTR(-EBUSY);
3401         else if (ffs_dev->ffs_acquire_dev_callback &&
3402             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3403                 ffs_dev = ERR_PTR(-ENOENT);
3404         else
3405                 ffs_dev->mounted = true;
3406
3407         ffs_dev_unlock();
3408         return ffs_dev;
3409 }
3410
3411 static void ffs_release_dev(struct ffs_data *ffs_data)
3412 {
3413         struct ffs_dev *ffs_dev;
3414
3415         ENTER();
3416         ffs_dev_lock();
3417
3418         ffs_dev = ffs_data->private_data;
3419         if (ffs_dev) {
3420                 ffs_dev->mounted = false;
3421
3422                 if (ffs_dev->ffs_release_dev_callback)
3423                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3424         }
3425
3426         ffs_dev_unlock();
3427 }
3428
3429 static int ffs_ready(struct ffs_data *ffs)
3430 {
3431         struct ffs_dev *ffs_obj;
3432         int ret = 0;
3433
3434         ENTER();
3435         ffs_dev_lock();
3436
3437         ffs_obj = ffs->private_data;
3438         if (!ffs_obj) {
3439                 ret = -EINVAL;
3440                 goto done;
3441         }
3442         if (WARN_ON(ffs_obj->desc_ready)) {
3443                 ret = -EBUSY;
3444                 goto done;
3445         }
3446
3447         ffs_obj->desc_ready = true;
3448         ffs_obj->ffs_data = ffs;
3449
3450         if (ffs_obj->ffs_ready_callback) {
3451                 ret = ffs_obj->ffs_ready_callback(ffs);
3452                 if (ret)
3453                         goto done;
3454         }
3455
3456         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3457 done:
3458         ffs_dev_unlock();
3459         return ret;
3460 }
3461
3462 static void ffs_closed(struct ffs_data *ffs)
3463 {
3464         struct ffs_dev *ffs_obj;
3465         struct f_fs_opts *opts;
3466
3467         ENTER();
3468         ffs_dev_lock();
3469
3470         ffs_obj = ffs->private_data;
3471         if (!ffs_obj)
3472                 goto done;
3473
3474         ffs_obj->desc_ready = false;
3475
3476         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3477             ffs_obj->ffs_closed_callback)
3478                 ffs_obj->ffs_closed_callback(ffs);
3479
3480         if (ffs_obj->opts)
3481                 opts = ffs_obj->opts;
3482         else
3483                 goto done;
3484
3485         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3486             || !atomic_read(&opts->func_inst.group.cg_item.ci_kref.refcount))
3487                 goto done;
3488
3489         unregister_gadget_item(ffs_obj->opts->
3490                                func_inst.group.cg_item.ci_parent->ci_parent);
3491 done:
3492         ffs_dev_unlock();
3493 }
3494
3495 /* Misc helper functions ****************************************************/
3496
3497 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3498 {
3499         return nonblock
3500                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3501                 : mutex_lock_interruptible(mutex);
3502 }
3503
3504 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3505 {
3506         char *data;
3507
3508         if (unlikely(!len))
3509                 return NULL;
3510
3511         data = kmalloc(len, GFP_KERNEL);
3512         if (unlikely(!data))
3513                 return ERR_PTR(-ENOMEM);
3514
3515         if (unlikely(copy_from_user(data, buf, len))) {
3516                 kfree(data);
3517                 return ERR_PTR(-EFAULT);
3518         }
3519
3520         pr_vdebug("Buffer from user space:\n");
3521         ffs_dump_mem("", data, len);
3522
3523         return data;
3524 }
3525
3526 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3527 MODULE_LICENSE("GPL");
3528 MODULE_AUTHOR("Michal Nazarewicz");