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 (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                 int desc_idx;
1647
1648                 if (ffs->gadget->speed == USB_SPEED_SUPER)
1649                         desc_idx = 2;
1650                 else if (ffs->gadget->speed == USB_SPEED_HIGH)
1651                         desc_idx = 1;
1652                 else
1653                         desc_idx = 0;
1654
1655                 /* fall-back to lower speed if desc missing for current speed */
1656                 do {
1657                         ds = ep->descs[desc_idx];
1658                 } while (!ds && --desc_idx >= 0);
1659
1660                 if (!ds) {
1661                         ret = -EINVAL;
1662                         break;
1663                 }
1664
1665                 ep->ep->driver_data = ep;
1666                 ep->ep->desc = ds;
1667                 ret = usb_ep_enable(ep->ep);
1668                 if (likely(!ret)) {
1669                         epfile->ep = ep;
1670                         epfile->in = usb_endpoint_dir_in(ds);
1671                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1672                 } else {
1673                         break;
1674                 }
1675
1676                 wake_up(&epfile->wait);
1677
1678                 ++ep;
1679                 ++epfile;
1680         } while (--count);
1681         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1682
1683         return ret;
1684 }
1685
1686
1687 /* Parsing and building descriptors and strings *****************************/
1688
1689 /*
1690  * This validates if data pointed by data is a valid USB descriptor as
1691  * well as record how many interfaces, endpoints and strings are
1692  * required by given configuration.  Returns address after the
1693  * descriptor or NULL if data is invalid.
1694  */
1695
1696 enum ffs_entity_type {
1697         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1698 };
1699
1700 enum ffs_os_desc_type {
1701         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1702 };
1703
1704 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1705                                    u8 *valuep,
1706                                    struct usb_descriptor_header *desc,
1707                                    void *priv);
1708
1709 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1710                                     struct usb_os_desc_header *h, void *data,
1711                                     unsigned len, void *priv);
1712
1713 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1714                                            ffs_entity_callback entity,
1715                                            void *priv)
1716 {
1717         struct usb_descriptor_header *_ds = (void *)data;
1718         u8 length;
1719         int ret;
1720
1721         ENTER();
1722
1723         /* At least two bytes are required: length and type */
1724         if (len < 2) {
1725                 pr_vdebug("descriptor too short\n");
1726                 return -EINVAL;
1727         }
1728
1729         /* If we have at least as many bytes as the descriptor takes? */
1730         length = _ds->bLength;
1731         if (len < length) {
1732                 pr_vdebug("descriptor longer then available data\n");
1733                 return -EINVAL;
1734         }
1735
1736 #define __entity_check_INTERFACE(val)  1
1737 #define __entity_check_STRING(val)     (val)
1738 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1739 #define __entity(type, val) do {                                        \
1740                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1741                 if (unlikely(!__entity_check_ ##type(val))) {           \
1742                         pr_vdebug("invalid entity's value\n");          \
1743                         return -EINVAL;                                 \
1744                 }                                                       \
1745                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1746                 if (unlikely(ret < 0)) {                                \
1747                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1748                                  (val), ret);                           \
1749                         return ret;                                     \
1750                 }                                                       \
1751         } while (0)
1752
1753         /* Parse descriptor depending on type. */
1754         switch (_ds->bDescriptorType) {
1755         case USB_DT_DEVICE:
1756         case USB_DT_CONFIG:
1757         case USB_DT_STRING:
1758         case USB_DT_DEVICE_QUALIFIER:
1759                 /* function can't have any of those */
1760                 pr_vdebug("descriptor reserved for gadget: %d\n",
1761                       _ds->bDescriptorType);
1762                 return -EINVAL;
1763
1764         case USB_DT_INTERFACE: {
1765                 struct usb_interface_descriptor *ds = (void *)_ds;
1766                 pr_vdebug("interface descriptor\n");
1767                 if (length != sizeof *ds)
1768                         goto inv_length;
1769
1770                 __entity(INTERFACE, ds->bInterfaceNumber);
1771                 if (ds->iInterface)
1772                         __entity(STRING, ds->iInterface);
1773         }
1774                 break;
1775
1776         case USB_DT_ENDPOINT: {
1777                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1778                 pr_vdebug("endpoint descriptor\n");
1779                 if (length != USB_DT_ENDPOINT_SIZE &&
1780                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1781                         goto inv_length;
1782                 __entity(ENDPOINT, ds->bEndpointAddress);
1783         }
1784                 break;
1785
1786         case HID_DT_HID:
1787                 pr_vdebug("hid descriptor\n");
1788                 if (length != sizeof(struct hid_descriptor))
1789                         goto inv_length;
1790                 break;
1791
1792         case USB_DT_OTG:
1793                 if (length != sizeof(struct usb_otg_descriptor))
1794                         goto inv_length;
1795                 break;
1796
1797         case USB_DT_INTERFACE_ASSOCIATION: {
1798                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1799                 pr_vdebug("interface association descriptor\n");
1800                 if (length != sizeof *ds)
1801                         goto inv_length;
1802                 if (ds->iFunction)
1803                         __entity(STRING, ds->iFunction);
1804         }
1805                 break;
1806
1807         case USB_DT_SS_ENDPOINT_COMP:
1808                 pr_vdebug("EP SS companion descriptor\n");
1809                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
1810                         goto inv_length;
1811                 break;
1812
1813         case USB_DT_OTHER_SPEED_CONFIG:
1814         case USB_DT_INTERFACE_POWER:
1815         case USB_DT_DEBUG:
1816         case USB_DT_SECURITY:
1817         case USB_DT_CS_RADIO_CONTROL:
1818                 /* TODO */
1819                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1820                 return -EINVAL;
1821
1822         default:
1823                 /* We should never be here */
1824                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1825                 return -EINVAL;
1826
1827 inv_length:
1828                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1829                           _ds->bLength, _ds->bDescriptorType);
1830                 return -EINVAL;
1831         }
1832
1833 #undef __entity
1834 #undef __entity_check_DESCRIPTOR
1835 #undef __entity_check_INTERFACE
1836 #undef __entity_check_STRING
1837 #undef __entity_check_ENDPOINT
1838
1839         return length;
1840 }
1841
1842 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1843                                      ffs_entity_callback entity, void *priv)
1844 {
1845         const unsigned _len = len;
1846         unsigned long num = 0;
1847
1848         ENTER();
1849
1850         for (;;) {
1851                 int ret;
1852
1853                 if (num == count)
1854                         data = NULL;
1855
1856                 /* Record "descriptor" entity */
1857                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1858                 if (unlikely(ret < 0)) {
1859                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1860                                  num, ret);
1861                         return ret;
1862                 }
1863
1864                 if (!data)
1865                         return _len - len;
1866
1867                 ret = ffs_do_single_desc(data, len, entity, priv);
1868                 if (unlikely(ret < 0)) {
1869                         pr_debug("%s returns %d\n", __func__, ret);
1870                         return ret;
1871                 }
1872
1873                 len -= ret;
1874                 data += ret;
1875                 ++num;
1876         }
1877 }
1878
1879 static int __ffs_data_do_entity(enum ffs_entity_type type,
1880                                 u8 *valuep, struct usb_descriptor_header *desc,
1881                                 void *priv)
1882 {
1883         struct ffs_desc_helper *helper = priv;
1884         struct usb_endpoint_descriptor *d;
1885
1886         ENTER();
1887
1888         switch (type) {
1889         case FFS_DESCRIPTOR:
1890                 break;
1891
1892         case FFS_INTERFACE:
1893                 /*
1894                  * Interfaces are indexed from zero so if we
1895                  * encountered interface "n" then there are at least
1896                  * "n+1" interfaces.
1897                  */
1898                 if (*valuep >= helper->interfaces_count)
1899                         helper->interfaces_count = *valuep + 1;
1900                 break;
1901
1902         case FFS_STRING:
1903                 /*
1904                  * Strings are indexed from 1 (0 is magic ;) reserved
1905                  * for languages list or some such)
1906                  */
1907                 if (*valuep > helper->ffs->strings_count)
1908                         helper->ffs->strings_count = *valuep;
1909                 break;
1910
1911         case FFS_ENDPOINT:
1912                 d = (void *)desc;
1913                 helper->eps_count++;
1914                 if (helper->eps_count >= 15)
1915                         return -EINVAL;
1916                 /* Check if descriptors for any speed were already parsed */
1917                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
1918                         helper->ffs->eps_addrmap[helper->eps_count] =
1919                                 d->bEndpointAddress;
1920                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
1921                                 d->bEndpointAddress)
1922                         return -EINVAL;
1923                 break;
1924         }
1925
1926         return 0;
1927 }
1928
1929 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
1930                                    struct usb_os_desc_header *desc)
1931 {
1932         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
1933         u16 w_index = le16_to_cpu(desc->wIndex);
1934
1935         if (bcd_version != 1) {
1936                 pr_vdebug("unsupported os descriptors version: %d",
1937                           bcd_version);
1938                 return -EINVAL;
1939         }
1940         switch (w_index) {
1941         case 0x4:
1942                 *next_type = FFS_OS_DESC_EXT_COMPAT;
1943                 break;
1944         case 0x5:
1945                 *next_type = FFS_OS_DESC_EXT_PROP;
1946                 break;
1947         default:
1948                 pr_vdebug("unsupported os descriptor type: %d", w_index);
1949                 return -EINVAL;
1950         }
1951
1952         return sizeof(*desc);
1953 }
1954
1955 /*
1956  * Process all extended compatibility/extended property descriptors
1957  * of a feature descriptor
1958  */
1959 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
1960                                               enum ffs_os_desc_type type,
1961                                               u16 feature_count,
1962                                               ffs_os_desc_callback entity,
1963                                               void *priv,
1964                                               struct usb_os_desc_header *h)
1965 {
1966         int ret;
1967         const unsigned _len = len;
1968
1969         ENTER();
1970
1971         /* loop over all ext compat/ext prop descriptors */
1972         while (feature_count--) {
1973                 ret = entity(type, h, data, len, priv);
1974                 if (unlikely(ret < 0)) {
1975                         pr_debug("bad OS descriptor, type: %d\n", type);
1976                         return ret;
1977                 }
1978                 data += ret;
1979                 len -= ret;
1980         }
1981         return _len - len;
1982 }
1983
1984 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
1985 static int __must_check ffs_do_os_descs(unsigned count,
1986                                         char *data, unsigned len,
1987                                         ffs_os_desc_callback entity, void *priv)
1988 {
1989         const unsigned _len = len;
1990         unsigned long num = 0;
1991
1992         ENTER();
1993
1994         for (num = 0; num < count; ++num) {
1995                 int ret;
1996                 enum ffs_os_desc_type type;
1997                 u16 feature_count;
1998                 struct usb_os_desc_header *desc = (void *)data;
1999
2000                 if (len < sizeof(*desc))
2001                         return -EINVAL;
2002
2003                 /*
2004                  * Record "descriptor" entity.
2005                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2006                  * Move the data pointer to the beginning of extended
2007                  * compatibilities proper or extended properties proper
2008                  * portions of the data
2009                  */
2010                 if (le32_to_cpu(desc->dwLength) > len)
2011                         return -EINVAL;
2012
2013                 ret = __ffs_do_os_desc_header(&type, desc);
2014                 if (unlikely(ret < 0)) {
2015                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2016                                  num, ret);
2017                         return ret;
2018                 }
2019                 /*
2020                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2021                  */
2022                 feature_count = le16_to_cpu(desc->wCount);
2023                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2024                     (feature_count > 255 || desc->Reserved))
2025                                 return -EINVAL;
2026                 len -= ret;
2027                 data += ret;
2028
2029                 /*
2030                  * Process all function/property descriptors
2031                  * of this Feature Descriptor
2032                  */
2033                 ret = ffs_do_single_os_desc(data, len, type,
2034                                             feature_count, entity, priv, desc);
2035                 if (unlikely(ret < 0)) {
2036                         pr_debug("%s returns %d\n", __func__, ret);
2037                         return ret;
2038                 }
2039
2040                 len -= ret;
2041                 data += ret;
2042         }
2043         return _len - len;
2044 }
2045
2046 /**
2047  * Validate contents of the buffer from userspace related to OS descriptors.
2048  */
2049 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2050                                  struct usb_os_desc_header *h, void *data,
2051                                  unsigned len, void *priv)
2052 {
2053         struct ffs_data *ffs = priv;
2054         u8 length;
2055
2056         ENTER();
2057
2058         switch (type) {
2059         case FFS_OS_DESC_EXT_COMPAT: {
2060                 struct usb_ext_compat_desc *d = data;
2061                 int i;
2062
2063                 if (len < sizeof(*d) ||
2064                     d->bFirstInterfaceNumber >= ffs->interfaces_count ||
2065                     d->Reserved1)
2066                         return -EINVAL;
2067                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2068                         if (d->Reserved2[i])
2069                                 return -EINVAL;
2070
2071                 length = sizeof(struct usb_ext_compat_desc);
2072         }
2073                 break;
2074         case FFS_OS_DESC_EXT_PROP: {
2075                 struct usb_ext_prop_desc *d = data;
2076                 u32 type, pdl;
2077                 u16 pnl;
2078
2079                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2080                         return -EINVAL;
2081                 length = le32_to_cpu(d->dwSize);
2082                 type = le32_to_cpu(d->dwPropertyDataType);
2083                 if (type < USB_EXT_PROP_UNICODE ||
2084                     type > USB_EXT_PROP_UNICODE_MULTI) {
2085                         pr_vdebug("unsupported os descriptor property type: %d",
2086                                   type);
2087                         return -EINVAL;
2088                 }
2089                 pnl = le16_to_cpu(d->wPropertyNameLength);
2090                 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2091                 if (length != 14 + pnl + pdl) {
2092                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2093                                   length, pnl, pdl, type);
2094                         return -EINVAL;
2095                 }
2096                 ++ffs->ms_os_descs_ext_prop_count;
2097                 /* property name reported to the host as "WCHAR"s */
2098                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2099                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2100         }
2101                 break;
2102         default:
2103                 pr_vdebug("unknown descriptor: %d\n", type);
2104                 return -EINVAL;
2105         }
2106         return length;
2107 }
2108
2109 static int __ffs_data_got_descs(struct ffs_data *ffs,
2110                                 char *const _data, size_t len)
2111 {
2112         char *data = _data, *raw_descs;
2113         unsigned os_descs_count = 0, counts[3], flags;
2114         int ret = -EINVAL, i;
2115         struct ffs_desc_helper helper;
2116
2117         ENTER();
2118
2119         if (get_unaligned_le32(data + 4) != len)
2120                 goto error;
2121
2122         switch (get_unaligned_le32(data)) {
2123         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2124                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2125                 data += 8;
2126                 len  -= 8;
2127                 break;
2128         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2129                 flags = get_unaligned_le32(data + 8);
2130                 ffs->user_flags = flags;
2131                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2132                               FUNCTIONFS_HAS_HS_DESC |
2133                               FUNCTIONFS_HAS_SS_DESC |
2134                               FUNCTIONFS_HAS_MS_OS_DESC |
2135                               FUNCTIONFS_VIRTUAL_ADDR |
2136                               FUNCTIONFS_EVENTFD)) {
2137                         ret = -ENOSYS;
2138                         goto error;
2139                 }
2140                 data += 12;
2141                 len  -= 12;
2142                 break;
2143         default:
2144                 goto error;
2145         }
2146
2147         if (flags & FUNCTIONFS_EVENTFD) {
2148                 if (len < 4)
2149                         goto error;
2150                 ffs->ffs_eventfd =
2151                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2152                 if (IS_ERR(ffs->ffs_eventfd)) {
2153                         ret = PTR_ERR(ffs->ffs_eventfd);
2154                         ffs->ffs_eventfd = NULL;
2155                         goto error;
2156                 }
2157                 data += 4;
2158                 len  -= 4;
2159         }
2160
2161         /* Read fs_count, hs_count and ss_count (if present) */
2162         for (i = 0; i < 3; ++i) {
2163                 if (!(flags & (1 << i))) {
2164                         counts[i] = 0;
2165                 } else if (len < 4) {
2166                         goto error;
2167                 } else {
2168                         counts[i] = get_unaligned_le32(data);
2169                         data += 4;
2170                         len  -= 4;
2171                 }
2172         }
2173         if (flags & (1 << i)) {
2174                 os_descs_count = get_unaligned_le32(data);
2175                 data += 4;
2176                 len -= 4;
2177         };
2178
2179         /* Read descriptors */
2180         raw_descs = data;
2181         helper.ffs = ffs;
2182         for (i = 0; i < 3; ++i) {
2183                 if (!counts[i])
2184                         continue;
2185                 helper.interfaces_count = 0;
2186                 helper.eps_count = 0;
2187                 ret = ffs_do_descs(counts[i], data, len,
2188                                    __ffs_data_do_entity, &helper);
2189                 if (ret < 0)
2190                         goto error;
2191                 if (!ffs->eps_count && !ffs->interfaces_count) {
2192                         ffs->eps_count = helper.eps_count;
2193                         ffs->interfaces_count = helper.interfaces_count;
2194                 } else {
2195                         if (ffs->eps_count != helper.eps_count) {
2196                                 ret = -EINVAL;
2197                                 goto error;
2198                         }
2199                         if (ffs->interfaces_count != helper.interfaces_count) {
2200                                 ret = -EINVAL;
2201                                 goto error;
2202                         }
2203                 }
2204                 data += ret;
2205                 len  -= ret;
2206         }
2207         if (os_descs_count) {
2208                 ret = ffs_do_os_descs(os_descs_count, data, len,
2209                                       __ffs_data_do_os_desc, ffs);
2210                 if (ret < 0)
2211                         goto error;
2212                 data += ret;
2213                 len -= ret;
2214         }
2215
2216         if (raw_descs == data || len) {
2217                 ret = -EINVAL;
2218                 goto error;
2219         }
2220
2221         ffs->raw_descs_data     = _data;
2222         ffs->raw_descs          = raw_descs;
2223         ffs->raw_descs_length   = data - raw_descs;
2224         ffs->fs_descs_count     = counts[0];
2225         ffs->hs_descs_count     = counts[1];
2226         ffs->ss_descs_count     = counts[2];
2227         ffs->ms_os_descs_count  = os_descs_count;
2228
2229         return 0;
2230
2231 error:
2232         kfree(_data);
2233         return ret;
2234 }
2235
2236 static int __ffs_data_got_strings(struct ffs_data *ffs,
2237                                   char *const _data, size_t len)
2238 {
2239         u32 str_count, needed_count, lang_count;
2240         struct usb_gadget_strings **stringtabs, *t;
2241         struct usb_string *strings, *s;
2242         const char *data = _data;
2243
2244         ENTER();
2245
2246         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2247                      get_unaligned_le32(data + 4) != len))
2248                 goto error;
2249         str_count  = get_unaligned_le32(data + 8);
2250         lang_count = get_unaligned_le32(data + 12);
2251
2252         /* if one is zero the other must be zero */
2253         if (unlikely(!str_count != !lang_count))
2254                 goto error;
2255
2256         /* Do we have at least as many strings as descriptors need? */
2257         needed_count = ffs->strings_count;
2258         if (unlikely(str_count < needed_count))
2259                 goto error;
2260
2261         /*
2262          * If we don't need any strings just return and free all
2263          * memory.
2264          */
2265         if (!needed_count) {
2266                 kfree(_data);
2267                 return 0;
2268         }
2269
2270         /* Allocate everything in one chunk so there's less maintenance. */
2271         {
2272                 unsigned i = 0;
2273                 vla_group(d);
2274                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2275                         lang_count + 1);
2276                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2277                 vla_item(d, struct usb_string, strings,
2278                         lang_count*(needed_count+1));
2279
2280                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2281
2282                 if (unlikely(!vlabuf)) {
2283                         kfree(_data);
2284                         return -ENOMEM;
2285                 }
2286
2287                 /* Initialize the VLA pointers */
2288                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2289                 t = vla_ptr(vlabuf, d, stringtab);
2290                 i = lang_count;
2291                 do {
2292                         *stringtabs++ = t++;
2293                 } while (--i);
2294                 *stringtabs = NULL;
2295
2296                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2297                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2298                 t = vla_ptr(vlabuf, d, stringtab);
2299                 s = vla_ptr(vlabuf, d, strings);
2300                 strings = s;
2301         }
2302
2303         /* For each language */
2304         data += 16;
2305         len -= 16;
2306
2307         do { /* lang_count > 0 so we can use do-while */
2308                 unsigned needed = needed_count;
2309
2310                 if (unlikely(len < 3))
2311                         goto error_free;
2312                 t->language = get_unaligned_le16(data);
2313                 t->strings  = s;
2314                 ++t;
2315
2316                 data += 2;
2317                 len -= 2;
2318
2319                 /* For each string */
2320                 do { /* str_count > 0 so we can use do-while */
2321                         size_t length = strnlen(data, len);
2322
2323                         if (unlikely(length == len))
2324                                 goto error_free;
2325
2326                         /*
2327                          * User may provide more strings then we need,
2328                          * if that's the case we simply ignore the
2329                          * rest
2330                          */
2331                         if (likely(needed)) {
2332                                 /*
2333                                  * s->id will be set while adding
2334                                  * function to configuration so for
2335                                  * now just leave garbage here.
2336                                  */
2337                                 s->s = data;
2338                                 --needed;
2339                                 ++s;
2340                         }
2341
2342                         data += length + 1;
2343                         len -= length + 1;
2344                 } while (--str_count);
2345
2346                 s->id = 0;   /* terminator */
2347                 s->s = NULL;
2348                 ++s;
2349
2350         } while (--lang_count);
2351
2352         /* Some garbage left? */
2353         if (unlikely(len))
2354                 goto error_free;
2355
2356         /* Done! */
2357         ffs->stringtabs = stringtabs;
2358         ffs->raw_strings = _data;
2359
2360         return 0;
2361
2362 error_free:
2363         kfree(stringtabs);
2364 error:
2365         kfree(_data);
2366         return -EINVAL;
2367 }
2368
2369
2370 /* Events handling and management *******************************************/
2371
2372 static void __ffs_event_add(struct ffs_data *ffs,
2373                             enum usb_functionfs_event_type type)
2374 {
2375         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2376         int neg = 0;
2377
2378         /*
2379          * Abort any unhandled setup
2380          *
2381          * We do not need to worry about some cmpxchg() changing value
2382          * of ffs->setup_state without holding the lock because when
2383          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2384          * the source does nothing.
2385          */
2386         if (ffs->setup_state == FFS_SETUP_PENDING)
2387                 ffs->setup_state = FFS_SETUP_CANCELLED;
2388
2389         /*
2390          * Logic of this function guarantees that there are at most four pending
2391          * evens on ffs->ev.types queue.  This is important because the queue
2392          * has space for four elements only and __ffs_ep0_read_events function
2393          * depends on that limit as well.  If more event types are added, those
2394          * limits have to be revisited or guaranteed to still hold.
2395          */
2396         switch (type) {
2397         case FUNCTIONFS_RESUME:
2398                 rem_type2 = FUNCTIONFS_SUSPEND;
2399                 /* FALL THROUGH */
2400         case FUNCTIONFS_SUSPEND:
2401         case FUNCTIONFS_SETUP:
2402                 rem_type1 = type;
2403                 /* Discard all similar events */
2404                 break;
2405
2406         case FUNCTIONFS_BIND:
2407         case FUNCTIONFS_UNBIND:
2408         case FUNCTIONFS_DISABLE:
2409         case FUNCTIONFS_ENABLE:
2410                 /* Discard everything other then power management. */
2411                 rem_type1 = FUNCTIONFS_SUSPEND;
2412                 rem_type2 = FUNCTIONFS_RESUME;
2413                 neg = 1;
2414                 break;
2415
2416         default:
2417                 WARN(1, "%d: unknown event, this should not happen\n", type);
2418                 return;
2419         }
2420
2421         {
2422                 u8 *ev  = ffs->ev.types, *out = ev;
2423                 unsigned n = ffs->ev.count;
2424                 for (; n; --n, ++ev)
2425                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2426                                 *out++ = *ev;
2427                         else
2428                                 pr_vdebug("purging event %d\n", *ev);
2429                 ffs->ev.count = out - ffs->ev.types;
2430         }
2431
2432         pr_vdebug("adding event %d\n", type);
2433         ffs->ev.types[ffs->ev.count++] = type;
2434         wake_up_locked(&ffs->ev.waitq);
2435         if (ffs->ffs_eventfd)
2436                 eventfd_signal(ffs->ffs_eventfd, 1);
2437 }
2438
2439 static void ffs_event_add(struct ffs_data *ffs,
2440                           enum usb_functionfs_event_type type)
2441 {
2442         unsigned long flags;
2443         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2444         __ffs_event_add(ffs, type);
2445         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2446 }
2447
2448 /* Bind/unbind USB function hooks *******************************************/
2449
2450 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2451 {
2452         int i;
2453
2454         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2455                 if (ffs->eps_addrmap[i] == endpoint_address)
2456                         return i;
2457         return -ENOENT;
2458 }
2459
2460 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2461                                     struct usb_descriptor_header *desc,
2462                                     void *priv)
2463 {
2464         struct usb_endpoint_descriptor *ds = (void *)desc;
2465         struct ffs_function *func = priv;
2466         struct ffs_ep *ffs_ep;
2467         unsigned ep_desc_id;
2468         int idx;
2469         static const char *speed_names[] = { "full", "high", "super" };
2470
2471         if (type != FFS_DESCRIPTOR)
2472                 return 0;
2473
2474         /*
2475          * If ss_descriptors is not NULL, we are reading super speed
2476          * descriptors; if hs_descriptors is not NULL, we are reading high
2477          * speed descriptors; otherwise, we are reading full speed
2478          * descriptors.
2479          */
2480         if (func->function.ss_descriptors) {
2481                 ep_desc_id = 2;
2482                 func->function.ss_descriptors[(long)valuep] = desc;
2483         } else if (func->function.hs_descriptors) {
2484                 ep_desc_id = 1;
2485                 func->function.hs_descriptors[(long)valuep] = desc;
2486         } else {
2487                 ep_desc_id = 0;
2488                 func->function.fs_descriptors[(long)valuep]    = desc;
2489         }
2490
2491         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2492                 return 0;
2493
2494         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2495         if (idx < 0)
2496                 return idx;
2497
2498         ffs_ep = func->eps + idx;
2499
2500         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2501                 pr_err("two %sspeed descriptors for EP %d\n",
2502                           speed_names[ep_desc_id],
2503                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2504                 return -EINVAL;
2505         }
2506         ffs_ep->descs[ep_desc_id] = ds;
2507
2508         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2509         if (ffs_ep->ep) {
2510                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2511                 if (!ds->wMaxPacketSize)
2512                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2513         } else {
2514                 struct usb_request *req;
2515                 struct usb_ep *ep;
2516                 u8 bEndpointAddress;
2517
2518                 /*
2519                  * We back up bEndpointAddress because autoconfig overwrites
2520                  * it with physical endpoint address.
2521                  */
2522                 bEndpointAddress = ds->bEndpointAddress;
2523                 pr_vdebug("autoconfig\n");
2524                 ep = usb_ep_autoconfig(func->gadget, ds);
2525                 if (unlikely(!ep))
2526                         return -ENOTSUPP;
2527                 ep->driver_data = func->eps + idx;
2528
2529                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2530                 if (unlikely(!req))
2531                         return -ENOMEM;
2532
2533                 ffs_ep->ep  = ep;
2534                 ffs_ep->req = req;
2535                 func->eps_revmap[ds->bEndpointAddress &
2536                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2537                 /*
2538                  * If we use virtual address mapping, we restore
2539                  * original bEndpointAddress value.
2540                  */
2541                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2542                         ds->bEndpointAddress = bEndpointAddress;
2543         }
2544         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2545
2546         return 0;
2547 }
2548
2549 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2550                                    struct usb_descriptor_header *desc,
2551                                    void *priv)
2552 {
2553         struct ffs_function *func = priv;
2554         unsigned idx;
2555         u8 newValue;
2556
2557         switch (type) {
2558         default:
2559         case FFS_DESCRIPTOR:
2560                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2561                 return 0;
2562
2563         case FFS_INTERFACE:
2564                 idx = *valuep;
2565                 if (func->interfaces_nums[idx] < 0) {
2566                         int id = usb_interface_id(func->conf, &func->function);
2567                         if (unlikely(id < 0))
2568                                 return id;
2569                         func->interfaces_nums[idx] = id;
2570                 }
2571                 newValue = func->interfaces_nums[idx];
2572                 break;
2573
2574         case FFS_STRING:
2575                 /* String' IDs are allocated when fsf_data is bound to cdev */
2576                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2577                 break;
2578
2579         case FFS_ENDPOINT:
2580                 /*
2581                  * USB_DT_ENDPOINT are handled in
2582                  * __ffs_func_bind_do_descs().
2583                  */
2584                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2585                         return 0;
2586
2587                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2588                 if (unlikely(!func->eps[idx].ep))
2589                         return -EINVAL;
2590
2591                 {
2592                         struct usb_endpoint_descriptor **descs;
2593                         descs = func->eps[idx].descs;
2594                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2595                 }
2596                 break;
2597         }
2598
2599         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2600         *valuep = newValue;
2601         return 0;
2602 }
2603
2604 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2605                                       struct usb_os_desc_header *h, void *data,
2606                                       unsigned len, void *priv)
2607 {
2608         struct ffs_function *func = priv;
2609         u8 length = 0;
2610
2611         switch (type) {
2612         case FFS_OS_DESC_EXT_COMPAT: {
2613                 struct usb_ext_compat_desc *desc = data;
2614                 struct usb_os_desc_table *t;
2615
2616                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2617                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2618                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2619                        ARRAY_SIZE(desc->CompatibleID) +
2620                        ARRAY_SIZE(desc->SubCompatibleID));
2621                 length = sizeof(*desc);
2622         }
2623                 break;
2624         case FFS_OS_DESC_EXT_PROP: {
2625                 struct usb_ext_prop_desc *desc = data;
2626                 struct usb_os_desc_table *t;
2627                 struct usb_os_desc_ext_prop *ext_prop;
2628                 char *ext_prop_name;
2629                 char *ext_prop_data;
2630
2631                 t = &func->function.os_desc_table[h->interface];
2632                 t->if_id = func->interfaces_nums[h->interface];
2633
2634                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2635                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2636
2637                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2638                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2639                 ext_prop->data_len = le32_to_cpu(*(u32 *)
2640                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2641                 length = ext_prop->name_len + ext_prop->data_len + 14;
2642
2643                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2644                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2645                         ext_prop->name_len;
2646
2647                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2648                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2649                         ext_prop->data_len;
2650                 memcpy(ext_prop_data,
2651                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2652                        ext_prop->data_len);
2653                 /* unicode data reported to the host as "WCHAR"s */
2654                 switch (ext_prop->type) {
2655                 case USB_EXT_PROP_UNICODE:
2656                 case USB_EXT_PROP_UNICODE_ENV:
2657                 case USB_EXT_PROP_UNICODE_LINK:
2658                 case USB_EXT_PROP_UNICODE_MULTI:
2659                         ext_prop->data_len *= 2;
2660                         break;
2661                 }
2662                 ext_prop->data = ext_prop_data;
2663
2664                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2665                        ext_prop->name_len);
2666                 /* property name reported to the host as "WCHAR"s */
2667                 ext_prop->name_len *= 2;
2668                 ext_prop->name = ext_prop_name;
2669
2670                 t->os_desc->ext_prop_len +=
2671                         ext_prop->name_len + ext_prop->data_len + 14;
2672                 ++t->os_desc->ext_prop_count;
2673                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2674         }
2675                 break;
2676         default:
2677                 pr_vdebug("unknown descriptor: %d\n", type);
2678         }
2679
2680         return length;
2681 }
2682
2683 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2684                                                 struct usb_configuration *c)
2685 {
2686         struct ffs_function *func = ffs_func_from_usb(f);
2687         struct f_fs_opts *ffs_opts =
2688                 container_of(f->fi, struct f_fs_opts, func_inst);
2689         int ret;
2690
2691         ENTER();
2692
2693         /*
2694          * Legacy gadget triggers binding in functionfs_ready_callback,
2695          * which already uses locking; taking the same lock here would
2696          * cause a deadlock.
2697          *
2698          * Configfs-enabled gadgets however do need ffs_dev_lock.
2699          */
2700         if (!ffs_opts->no_configfs)
2701                 ffs_dev_lock();
2702         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2703         func->ffs = ffs_opts->dev->ffs_data;
2704         if (!ffs_opts->no_configfs)
2705                 ffs_dev_unlock();
2706         if (ret)
2707                 return ERR_PTR(ret);
2708
2709         func->conf = c;
2710         func->gadget = c->cdev->gadget;
2711
2712         /*
2713          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2714          * configurations are bound in sequence with list_for_each_entry,
2715          * in each configuration its functions are bound in sequence
2716          * with list_for_each_entry, so we assume no race condition
2717          * with regard to ffs_opts->bound access
2718          */
2719         if (!ffs_opts->refcnt) {
2720                 ret = functionfs_bind(func->ffs, c->cdev);
2721                 if (ret)
2722                         return ERR_PTR(ret);
2723         }
2724         ffs_opts->refcnt++;
2725         func->function.strings = func->ffs->stringtabs;
2726
2727         return ffs_opts;
2728 }
2729
2730 static int _ffs_func_bind(struct usb_configuration *c,
2731                           struct usb_function *f)
2732 {
2733         struct ffs_function *func = ffs_func_from_usb(f);
2734         struct ffs_data *ffs = func->ffs;
2735
2736         const int full = !!func->ffs->fs_descs_count;
2737         const int high = gadget_is_dualspeed(func->gadget) &&
2738                 func->ffs->hs_descs_count;
2739         const int super = gadget_is_superspeed(func->gadget) &&
2740                 func->ffs->ss_descs_count;
2741
2742         int fs_len, hs_len, ss_len, ret, i;
2743
2744         /* Make it a single chunk, less management later on */
2745         vla_group(d);
2746         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2747         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2748                 full ? ffs->fs_descs_count + 1 : 0);
2749         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2750                 high ? ffs->hs_descs_count + 1 : 0);
2751         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2752                 super ? ffs->ss_descs_count + 1 : 0);
2753         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2754         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2755                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2756         vla_item_with_sz(d, char[16], ext_compat,
2757                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2758         vla_item_with_sz(d, struct usb_os_desc, os_desc,
2759                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2760         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2761                          ffs->ms_os_descs_ext_prop_count);
2762         vla_item_with_sz(d, char, ext_prop_name,
2763                          ffs->ms_os_descs_ext_prop_name_len);
2764         vla_item_with_sz(d, char, ext_prop_data,
2765                          ffs->ms_os_descs_ext_prop_data_len);
2766         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2767         char *vlabuf;
2768
2769         ENTER();
2770
2771         /* Has descriptors only for speeds gadget does not support */
2772         if (unlikely(!(full | high | super)))
2773                 return -ENOTSUPP;
2774
2775         /* Allocate a single chunk, less management later on */
2776         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
2777         if (unlikely(!vlabuf))
2778                 return -ENOMEM;
2779
2780         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
2781         ffs->ms_os_descs_ext_prop_name_avail =
2782                 vla_ptr(vlabuf, d, ext_prop_name);
2783         ffs->ms_os_descs_ext_prop_data_avail =
2784                 vla_ptr(vlabuf, d, ext_prop_data);
2785
2786         /* Copy descriptors  */
2787         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2788                ffs->raw_descs_length);
2789
2790         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2791         for (ret = ffs->eps_count; ret; --ret) {
2792                 struct ffs_ep *ptr;
2793
2794                 ptr = vla_ptr(vlabuf, d, eps);
2795                 ptr[ret].num = -1;
2796         }
2797
2798         /* Save pointers
2799          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2800         */
2801         func->eps             = vla_ptr(vlabuf, d, eps);
2802         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2803
2804         /*
2805          * Go through all the endpoint descriptors and allocate
2806          * endpoints first, so that later we can rewrite the endpoint
2807          * numbers without worrying that it may be described later on.
2808          */
2809         if (likely(full)) {
2810                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
2811                 fs_len = ffs_do_descs(ffs->fs_descs_count,
2812                                       vla_ptr(vlabuf, d, raw_descs),
2813                                       d_raw_descs__sz,
2814                                       __ffs_func_bind_do_descs, func);
2815                 if (unlikely(fs_len < 0)) {
2816                         ret = fs_len;
2817                         goto error;
2818                 }
2819         } else {
2820                 fs_len = 0;
2821         }
2822
2823         if (likely(high)) {
2824                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
2825                 hs_len = ffs_do_descs(ffs->hs_descs_count,
2826                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
2827                                       d_raw_descs__sz - fs_len,
2828                                       __ffs_func_bind_do_descs, func);
2829                 if (unlikely(hs_len < 0)) {
2830                         ret = hs_len;
2831                         goto error;
2832                 }
2833         } else {
2834                 hs_len = 0;
2835         }
2836
2837         if (likely(super)) {
2838                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
2839                 ss_len = ffs_do_descs(ffs->ss_descs_count,
2840                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
2841                                 d_raw_descs__sz - fs_len - hs_len,
2842                                 __ffs_func_bind_do_descs, func);
2843                 if (unlikely(ss_len < 0)) {
2844                         ret = ss_len;
2845                         goto error;
2846                 }
2847         } else {
2848                 ss_len = 0;
2849         }
2850
2851         /*
2852          * Now handle interface numbers allocation and interface and
2853          * endpoint numbers rewriting.  We can do that in one go
2854          * now.
2855          */
2856         ret = ffs_do_descs(ffs->fs_descs_count +
2857                            (high ? ffs->hs_descs_count : 0) +
2858                            (super ? ffs->ss_descs_count : 0),
2859                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
2860                            __ffs_func_bind_do_nums, func);
2861         if (unlikely(ret < 0))
2862                 goto error;
2863
2864         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
2865         if (c->cdev->use_os_string)
2866                 for (i = 0; i < ffs->interfaces_count; ++i) {
2867                         struct usb_os_desc *desc;
2868
2869                         desc = func->function.os_desc_table[i].os_desc =
2870                                 vla_ptr(vlabuf, d, os_desc) +
2871                                 i * sizeof(struct usb_os_desc);
2872                         desc->ext_compat_id =
2873                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
2874                         INIT_LIST_HEAD(&desc->ext_prop);
2875                 }
2876         ret = ffs_do_os_descs(ffs->ms_os_descs_count,
2877                               vla_ptr(vlabuf, d, raw_descs) +
2878                               fs_len + hs_len + ss_len,
2879                               d_raw_descs__sz - fs_len - hs_len - ss_len,
2880                               __ffs_func_bind_do_os_desc, func);
2881         if (unlikely(ret < 0))
2882                 goto error;
2883         func->function.os_desc_n =
2884                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
2885
2886         /* And we're done */
2887         ffs_event_add(ffs, FUNCTIONFS_BIND);
2888         return 0;
2889
2890 error:
2891         /* XXX Do we need to release all claimed endpoints here? */
2892         return ret;
2893 }
2894
2895 static int ffs_func_bind(struct usb_configuration *c,
2896                          struct usb_function *f)
2897 {
2898         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
2899         struct ffs_function *func = ffs_func_from_usb(f);
2900         int ret;
2901
2902         if (IS_ERR(ffs_opts))
2903                 return PTR_ERR(ffs_opts);
2904
2905         ret = _ffs_func_bind(c, f);
2906         if (ret && !--ffs_opts->refcnt)
2907                 functionfs_unbind(func->ffs);
2908
2909         return ret;
2910 }
2911
2912
2913 /* Other USB function hooks *************************************************/
2914
2915 static void ffs_reset_work(struct work_struct *work)
2916 {
2917         struct ffs_data *ffs = container_of(work,
2918                 struct ffs_data, reset_work);
2919         ffs_data_reset(ffs);
2920 }
2921
2922 static int ffs_func_set_alt(struct usb_function *f,
2923                             unsigned interface, unsigned alt)
2924 {
2925         struct ffs_function *func = ffs_func_from_usb(f);
2926         struct ffs_data *ffs = func->ffs;
2927         int ret = 0, intf;
2928
2929         if (alt != (unsigned)-1) {
2930                 intf = ffs_func_revmap_intf(func, interface);
2931                 if (unlikely(intf < 0))
2932                         return intf;
2933         }
2934
2935         if (ffs->func)
2936                 ffs_func_eps_disable(ffs->func);
2937
2938         if (ffs->state == FFS_DEACTIVATED) {
2939                 ffs->state = FFS_CLOSING;
2940                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
2941                 schedule_work(&ffs->reset_work);
2942                 return -ENODEV;
2943         }
2944
2945         if (ffs->state != FFS_ACTIVE)
2946                 return -ENODEV;
2947
2948         if (alt == (unsigned)-1) {
2949                 ffs->func = NULL;
2950                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
2951                 return 0;
2952         }
2953
2954         ffs->func = func;
2955         ret = ffs_func_eps_enable(func);
2956         if (likely(ret >= 0))
2957                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
2958         return ret;
2959 }
2960
2961 static void ffs_func_disable(struct usb_function *f)
2962 {
2963         ffs_func_set_alt(f, 0, (unsigned)-1);
2964 }
2965
2966 static int ffs_func_setup(struct usb_function *f,
2967                           const struct usb_ctrlrequest *creq)
2968 {
2969         struct ffs_function *func = ffs_func_from_usb(f);
2970         struct ffs_data *ffs = func->ffs;
2971         unsigned long flags;
2972         int ret;
2973
2974         ENTER();
2975
2976         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
2977         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
2978         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
2979         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
2980         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
2981
2982         /*
2983          * Most requests directed to interface go through here
2984          * (notable exceptions are set/get interface) so we need to
2985          * handle them.  All other either handled by composite or
2986          * passed to usb_configuration->setup() (if one is set).  No
2987          * matter, we will handle requests directed to endpoint here
2988          * as well (as it's straightforward) but what to do with any
2989          * other request?
2990          */
2991         if (ffs->state != FFS_ACTIVE)
2992                 return -ENODEV;
2993
2994         switch (creq->bRequestType & USB_RECIP_MASK) {
2995         case USB_RECIP_INTERFACE:
2996                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
2997                 if (unlikely(ret < 0))
2998                         return ret;
2999                 break;
3000
3001         case USB_RECIP_ENDPOINT:
3002                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3003                 if (unlikely(ret < 0))
3004                         return ret;
3005                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3006                         ret = func->ffs->eps_addrmap[ret];
3007                 break;
3008
3009         default:
3010                 return -EOPNOTSUPP;
3011         }
3012
3013         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3014         ffs->ev.setup = *creq;
3015         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3016         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3017         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3018
3019         return 0;
3020 }
3021
3022 static void ffs_func_suspend(struct usb_function *f)
3023 {
3024         ENTER();
3025         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3026 }
3027
3028 static void ffs_func_resume(struct usb_function *f)
3029 {
3030         ENTER();
3031         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3032 }
3033
3034
3035 /* Endpoint and interface numbers reverse mapping ***************************/
3036
3037 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3038 {
3039         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3040         return num ? num : -EDOM;
3041 }
3042
3043 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3044 {
3045         short *nums = func->interfaces_nums;
3046         unsigned count = func->ffs->interfaces_count;
3047
3048         for (; count; --count, ++nums) {
3049                 if (*nums >= 0 && *nums == intf)
3050                         return nums - func->interfaces_nums;
3051         }
3052
3053         return -EDOM;
3054 }
3055
3056
3057 /* Devices management *******************************************************/
3058
3059 static LIST_HEAD(ffs_devices);
3060
3061 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3062 {
3063         struct ffs_dev *dev;
3064
3065         list_for_each_entry(dev, &ffs_devices, entry) {
3066                 if (!dev->name || !name)
3067                         continue;
3068                 if (strcmp(dev->name, name) == 0)
3069                         return dev;
3070         }
3071
3072         return NULL;
3073 }
3074
3075 /*
3076  * ffs_lock must be taken by the caller of this function
3077  */
3078 static struct ffs_dev *_ffs_get_single_dev(void)
3079 {
3080         struct ffs_dev *dev;
3081
3082         if (list_is_singular(&ffs_devices)) {
3083                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3084                 if (dev->single)
3085                         return dev;
3086         }
3087
3088         return NULL;
3089 }
3090
3091 /*
3092  * ffs_lock must be taken by the caller of this function
3093  */
3094 static struct ffs_dev *_ffs_find_dev(const char *name)
3095 {
3096         struct ffs_dev *dev;
3097
3098         dev = _ffs_get_single_dev();
3099         if (dev)
3100                 return dev;
3101
3102         return _ffs_do_find_dev(name);
3103 }
3104
3105 /* Configfs support *********************************************************/
3106
3107 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3108 {
3109         return container_of(to_config_group(item), struct f_fs_opts,
3110                             func_inst.group);
3111 }
3112
3113 static void ffs_attr_release(struct config_item *item)
3114 {
3115         struct f_fs_opts *opts = to_ffs_opts(item);
3116
3117         usb_put_function_instance(&opts->func_inst);
3118 }
3119
3120 static struct configfs_item_operations ffs_item_ops = {
3121         .release        = ffs_attr_release,
3122 };
3123
3124 static struct config_item_type ffs_func_type = {
3125         .ct_item_ops    = &ffs_item_ops,
3126         .ct_owner       = THIS_MODULE,
3127 };
3128
3129
3130 /* Function registration interface ******************************************/
3131
3132 static void ffs_free_inst(struct usb_function_instance *f)
3133 {
3134         struct f_fs_opts *opts;
3135
3136         opts = to_f_fs_opts(f);
3137         ffs_dev_lock();
3138         _ffs_free_dev(opts->dev);
3139         ffs_dev_unlock();
3140         kfree(opts);
3141 }
3142
3143 #define MAX_INST_NAME_LEN       40
3144
3145 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3146 {
3147         struct f_fs_opts *opts;
3148         char *ptr;
3149         const char *tmp;
3150         int name_len, ret;
3151
3152         name_len = strlen(name) + 1;
3153         if (name_len > MAX_INST_NAME_LEN)
3154                 return -ENAMETOOLONG;
3155
3156         ptr = kstrndup(name, name_len, GFP_KERNEL);
3157         if (!ptr)
3158                 return -ENOMEM;
3159
3160         opts = to_f_fs_opts(fi);
3161         tmp = NULL;
3162
3163         ffs_dev_lock();
3164
3165         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
3166         ret = _ffs_name_dev(opts->dev, ptr);
3167         if (ret) {
3168                 kfree(ptr);
3169                 ffs_dev_unlock();
3170                 return ret;
3171         }
3172         opts->dev->name_allocated = true;
3173
3174         ffs_dev_unlock();
3175
3176         kfree(tmp);
3177
3178         return 0;
3179 }
3180
3181 static struct usb_function_instance *ffs_alloc_inst(void)
3182 {
3183         struct f_fs_opts *opts;
3184         struct ffs_dev *dev;
3185
3186         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3187         if (!opts)
3188                 return ERR_PTR(-ENOMEM);
3189
3190         opts->func_inst.set_inst_name = ffs_set_inst_name;
3191         opts->func_inst.free_func_inst = ffs_free_inst;
3192         ffs_dev_lock();
3193         dev = _ffs_alloc_dev();
3194         ffs_dev_unlock();
3195         if (IS_ERR(dev)) {
3196                 kfree(opts);
3197                 return ERR_CAST(dev);
3198         }
3199         opts->dev = dev;
3200         dev->opts = opts;
3201
3202         config_group_init_type_name(&opts->func_inst.group, "",
3203                                     &ffs_func_type);
3204         return &opts->func_inst;
3205 }
3206
3207 static void ffs_free(struct usb_function *f)
3208 {
3209         kfree(ffs_func_from_usb(f));
3210 }
3211
3212 static void ffs_func_unbind(struct usb_configuration *c,
3213                             struct usb_function *f)
3214 {
3215         struct ffs_function *func = ffs_func_from_usb(f);
3216         struct ffs_data *ffs = func->ffs;
3217         struct f_fs_opts *opts =
3218                 container_of(f->fi, struct f_fs_opts, func_inst);
3219         struct ffs_ep *ep = func->eps;
3220         unsigned count = ffs->eps_count;
3221         unsigned long flags;
3222
3223         ENTER();
3224         if (ffs->func == func) {
3225                 ffs_func_eps_disable(func);
3226                 ffs->func = NULL;
3227         }
3228
3229         if (!--opts->refcnt)
3230                 functionfs_unbind(ffs);
3231
3232         /* cleanup after autoconfig */
3233         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3234         do {
3235                 if (ep->ep && ep->req)
3236                         usb_ep_free_request(ep->ep, ep->req);
3237                 ep->req = NULL;
3238                 ++ep;
3239         } while (--count);
3240         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3241         kfree(func->eps);
3242         func->eps = NULL;
3243         /*
3244          * eps, descriptors and interfaces_nums are allocated in the
3245          * same chunk so only one free is required.
3246          */
3247         func->function.fs_descriptors = NULL;
3248         func->function.hs_descriptors = NULL;
3249         func->function.ss_descriptors = NULL;
3250         func->interfaces_nums = NULL;
3251
3252         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3253 }
3254
3255 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3256 {
3257         struct ffs_function *func;
3258
3259         ENTER();
3260
3261         func = kzalloc(sizeof(*func), GFP_KERNEL);
3262         if (unlikely(!func))
3263                 return ERR_PTR(-ENOMEM);
3264
3265         func->function.name    = "Function FS Gadget";
3266
3267         func->function.bind    = ffs_func_bind;
3268         func->function.unbind  = ffs_func_unbind;
3269         func->function.set_alt = ffs_func_set_alt;
3270         func->function.disable = ffs_func_disable;
3271         func->function.setup   = ffs_func_setup;
3272         func->function.suspend = ffs_func_suspend;
3273         func->function.resume  = ffs_func_resume;
3274         func->function.free_func = ffs_free;
3275
3276         return &func->function;
3277 }
3278
3279 /*
3280  * ffs_lock must be taken by the caller of this function
3281  */
3282 static struct ffs_dev *_ffs_alloc_dev(void)
3283 {
3284         struct ffs_dev *dev;
3285         int ret;
3286
3287         if (_ffs_get_single_dev())
3288                         return ERR_PTR(-EBUSY);
3289
3290         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3291         if (!dev)
3292                 return ERR_PTR(-ENOMEM);
3293
3294         if (list_empty(&ffs_devices)) {
3295                 ret = functionfs_init();
3296                 if (ret) {
3297                         kfree(dev);
3298                         return ERR_PTR(ret);
3299                 }
3300         }
3301
3302         list_add(&dev->entry, &ffs_devices);
3303
3304         return dev;
3305 }
3306
3307 /*
3308  * ffs_lock must be taken by the caller of this function
3309  * The caller is responsible for "name" being available whenever f_fs needs it
3310  */
3311 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
3312 {
3313         struct ffs_dev *existing;
3314
3315         existing = _ffs_do_find_dev(name);
3316         if (existing)
3317                 return -EBUSY;
3318
3319         dev->name = name;
3320
3321         return 0;
3322 }
3323
3324 /*
3325  * The caller is responsible for "name" being available whenever f_fs needs it
3326  */
3327 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3328 {
3329         int ret;
3330
3331         ffs_dev_lock();
3332         ret = _ffs_name_dev(dev, name);
3333         ffs_dev_unlock();
3334
3335         return ret;
3336 }
3337 EXPORT_SYMBOL_GPL(ffs_name_dev);
3338
3339 int ffs_single_dev(struct ffs_dev *dev)
3340 {
3341         int ret;
3342
3343         ret = 0;
3344         ffs_dev_lock();
3345
3346         if (!list_is_singular(&ffs_devices))
3347                 ret = -EBUSY;
3348         else
3349                 dev->single = true;
3350
3351         ffs_dev_unlock();
3352         return ret;
3353 }
3354 EXPORT_SYMBOL_GPL(ffs_single_dev);
3355
3356 /*
3357  * ffs_lock must be taken by the caller of this function
3358  */
3359 static void _ffs_free_dev(struct ffs_dev *dev)
3360 {
3361         list_del(&dev->entry);
3362         if (dev->name_allocated)
3363                 kfree(dev->name);
3364         kfree(dev);
3365         if (list_empty(&ffs_devices))
3366                 functionfs_cleanup();
3367 }
3368
3369 static void *ffs_acquire_dev(const char *dev_name)
3370 {
3371         struct ffs_dev *ffs_dev;
3372
3373         ENTER();
3374         ffs_dev_lock();
3375
3376         ffs_dev = _ffs_find_dev(dev_name);
3377         if (!ffs_dev)
3378                 ffs_dev = ERR_PTR(-ENOENT);
3379         else if (ffs_dev->mounted)
3380                 ffs_dev = ERR_PTR(-EBUSY);
3381         else if (ffs_dev->ffs_acquire_dev_callback &&
3382             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3383                 ffs_dev = ERR_PTR(-ENOENT);
3384         else
3385                 ffs_dev->mounted = true;
3386
3387         ffs_dev_unlock();
3388         return ffs_dev;
3389 }
3390
3391 static void ffs_release_dev(struct ffs_data *ffs_data)
3392 {
3393         struct ffs_dev *ffs_dev;
3394
3395         ENTER();
3396         ffs_dev_lock();
3397
3398         ffs_dev = ffs_data->private_data;
3399         if (ffs_dev) {
3400                 ffs_dev->mounted = false;
3401
3402                 if (ffs_dev->ffs_release_dev_callback)
3403                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3404         }
3405
3406         ffs_dev_unlock();
3407 }
3408
3409 static int ffs_ready(struct ffs_data *ffs)
3410 {
3411         struct ffs_dev *ffs_obj;
3412         int ret = 0;
3413
3414         ENTER();
3415         ffs_dev_lock();
3416
3417         ffs_obj = ffs->private_data;
3418         if (!ffs_obj) {
3419                 ret = -EINVAL;
3420                 goto done;
3421         }
3422         if (WARN_ON(ffs_obj->desc_ready)) {
3423                 ret = -EBUSY;
3424                 goto done;
3425         }
3426
3427         ffs_obj->desc_ready = true;
3428         ffs_obj->ffs_data = ffs;
3429
3430         if (ffs_obj->ffs_ready_callback) {
3431                 ret = ffs_obj->ffs_ready_callback(ffs);
3432                 if (ret)
3433                         goto done;
3434         }
3435
3436         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3437 done:
3438         ffs_dev_unlock();
3439         return ret;
3440 }
3441
3442 static void ffs_closed(struct ffs_data *ffs)
3443 {
3444         struct ffs_dev *ffs_obj;
3445         struct f_fs_opts *opts;
3446
3447         ENTER();
3448         ffs_dev_lock();
3449
3450         ffs_obj = ffs->private_data;
3451         if (!ffs_obj)
3452                 goto done;
3453
3454         ffs_obj->desc_ready = false;
3455
3456         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3457             ffs_obj->ffs_closed_callback)
3458                 ffs_obj->ffs_closed_callback(ffs);
3459
3460         if (ffs_obj->opts)
3461                 opts = ffs_obj->opts;
3462         else
3463                 goto done;
3464
3465         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3466             || !atomic_read(&opts->func_inst.group.cg_item.ci_kref.refcount))
3467                 goto done;
3468
3469         unregister_gadget_item(ffs_obj->opts->
3470                                func_inst.group.cg_item.ci_parent->ci_parent);
3471 done:
3472         ffs_dev_unlock();
3473 }
3474
3475 /* Misc helper functions ****************************************************/
3476
3477 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3478 {
3479         return nonblock
3480                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3481                 : mutex_lock_interruptible(mutex);
3482 }
3483
3484 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3485 {
3486         char *data;
3487
3488         if (unlikely(!len))
3489                 return NULL;
3490
3491         data = kmalloc(len, GFP_KERNEL);
3492         if (unlikely(!data))
3493                 return ERR_PTR(-ENOMEM);
3494
3495         if (unlikely(copy_from_user(data, buf, len))) {
3496                 kfree(data);
3497                 return ERR_PTR(-EFAULT);
3498         }
3499
3500         pr_vdebug("Buffer from user space:\n");
3501         ffs_dump_mem("", data, len);
3502
3503         return data;
3504 }
3505
3506 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3507 MODULE_LICENSE("GPL");
3508 MODULE_AUTHOR("Michal Nazarewicz");