drivers/net/usb/usbnet.c

   1 /*
   2  * USB Network driver infrastructure
   3  * Copyright (C) 2000-2005 by David Brownell
   4  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 /*
  22  * This is a generic "USB networking" framework that works with several
  23  * kinds of full and high speed networking devices:  host-to-host cables,
  24  * smart usb peripherals, and actual Ethernet adapters.
  25  *
  26  * These devices usually differ in terms of control protocols (if they
  27  * even have one!) and sometimes they define new framing to wrap or batch
  28  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
  29  * so interface (un)binding, endpoint I/O queues, fault handling, and other
  30  * issues can usefully be addressed by this framework.
  31  */
  32
  33 // #define      DEBUG                   // error path messages, extra info
  34 // #define      VERBOSE                 // more; success messages
  35
  36 #include <linux/module.h>
  37 #include <linux/init.h>
  38 #include <linux/netdevice.h>
  39 #include <linux/etherdevice.h>
  40 #include <linux/ctype.h>
  41 #include <linux/ethtool.h>
  42 #include <linux/workqueue.h>
  43 #include <linux/mii.h>
  44 #include <linux/usb.h>
  45 #include <linux/usb/usbnet.h>
  46 #include <linux/slab.h>
  47 #include <linux/kernel.h>
  48 #include <linux/pm_runtime.h>
  49
  50 #define DRIVER_VERSION          "22-Aug-2005"
  51
  52
  53 /*-------------------------------------------------------------------------*/
  54
  55 /*
  56  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
  57  * Several dozen bytes of IPv4 data can fit in two such transactions.
  58  * One maximum size Ethernet packet takes twenty four of them.
  59  * For high speed, each frame comfortably fits almost 36 max size
  60  * Ethernet packets (so queues should be bigger).
  61  *
  62  * REVISIT qlens should be members of 'struct usbnet'; the goal is to
  63  * let the USB host controller be busy for 5msec or more before an irq
  64  * is required, under load.  Jumbograms change the equation.
  65  */
  66 #define RX_MAX_QUEUE_MEMORY (60 * 1518)
  67 #define RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
  68                         (RX_MAX_QUEUE_MEMORY/(dev)->rx_urb_size) : 4)
  69 #define TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
  70                         (RX_MAX_QUEUE_MEMORY/(dev)->hard_mtu) : 4)
  71
  72 // reawaken network queue this soon after stopping; else watchdog barks
  73 #define TX_TIMEOUT_JIFFIES      (5*HZ)
  74
  75 // throttle rx/tx briefly after some faults, so khubd might disconnect()
  76 // us (it polls at HZ/4 usually) before we report too many false errors.
  77 #define THROTTLE_JIFFIES        (HZ/8)
  78
  79 // between wakeups
  80 #define UNLINK_TIMEOUT_MS       3
  81
  82 /*-------------------------------------------------------------------------*/
  83
  84 // randomly generated ethernet address
  85 static u8       node_id [ETH_ALEN];
  86
  87 static const char driver_name [] = "usbnet";
  88
  89 /* use ethtool to change the level for any given device */
  90 static int msg_level = -1;
  91 module_param (msg_level, int, 0);
  92 MODULE_PARM_DESC (msg_level, "Override default message level");
  93
  94 /*-------------------------------------------------------------------------*/
  95
  96 /* handles CDC Ethernet and many other network "bulk data" interfaces */
  97 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
  98 {
  99         int                             tmp;
 100         struct usb_host_interface       *alt = NULL;
 101         struct usb_host_endpoint        *in = NULL, *out = NULL;
 102         struct usb_host_endpoint        *status = NULL;
 103
 104         for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
 105                 unsigned        ep;
 106
 107                 in = out = status = NULL;
 108                 alt = intf->altsetting + tmp;
 109
 110                 /* take the first altsetting with in-bulk + out-bulk;
 111                  * remember any status endpoint, just in case;
 112                  * ignore other endpoints and altsettings.
 113                  */
 114                 for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
 115                         struct usb_host_endpoint        *e;
 116                         int                             intr = 0;
 117
 118                         e = alt->endpoint + ep;
 119                         switch (e->desc.bmAttributes) {
 120                         case USB_ENDPOINT_XFER_INT:
 121                                 if (!usb_endpoint_dir_in(&e->desc))
 122                                         continue;
 123                                 intr = 1;
 124                                 /* FALLTHROUGH */
 125                         case USB_ENDPOINT_XFER_BULK:
 126                                 break;
 127                         default:
 128                                 continue;
 129                         }
 130                         if (usb_endpoint_dir_in(&e->desc)) {
 131                                 if (!intr && !in)
 132                                         in = e;
 133                                 else if (intr && !status)
 134                                         status = e;
 135                         } else {
 136                                 if (!out)
 137                                         out = e;
 138                         }
 139                 }
 140                 if (in && out)
 141                         break;
 142         }
 143         if (!alt || !in || !out)
 144                 return -EINVAL;
 145
 146         if (alt->desc.bAlternateSetting != 0 ||
 147             !(dev->driver_info->flags & FLAG_NO_SETINT)) {
 148                 tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
 149                                 alt->desc.bAlternateSetting);
 150                 if (tmp < 0)
 151                         return tmp;
 152         }
 153
 154         dev->in = usb_rcvbulkpipe (dev->udev,
 155                         in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
 156         dev->out = usb_sndbulkpipe (dev->udev,
 157                         out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
 158         dev->status = status;
 159         return 0;
 160 }
 161 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
 162
 163 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
 164 {
 165         int             tmp, i;
 166         unsigned char   buf [13];
 167
 168         tmp = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
 169         if (tmp != 12) {
 170                 dev_dbg(&dev->udev->dev,
 171                         "bad MAC string %d fetch, %d\n", iMACAddress, tmp);
 172                 if (tmp >= 0)
 173                         tmp = -EINVAL;
 174                 return tmp;
 175         }
 176         for (i = tmp = 0; i < 6; i++, tmp += 2)
 177                 dev->net->dev_addr [i] =
 178                         (hex_to_bin(buf[tmp]) << 4) + hex_to_bin(buf[tmp + 1]);
 179         return 0;
 180 }
 181 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
 182
 183 static void intr_complete (struct urb *urb)
 184 {
 185         struct usbnet   *dev = urb->context;
 186         int             status = urb->status;
 187
 188         switch (status) {
 189         /* success */
 190         case 0:
 191                 dev->driver_info->status(dev, urb);
 192                 break;
 193
 194         /* software-driven interface shutdown */
 195         case -ENOENT:           /* urb killed */
 196         case -ESHUTDOWN:        /* hardware gone */
 197                 netif_dbg(dev, ifdown, dev->net,
 198                           "intr shutdown, code %d\n", status);
 199                 return;
 200
 201         /* NOTE:  not throttling like RX/TX, since this endpoint
 202          * already polls infrequently
 203          */
 204         default:
 205                 netdev_dbg(dev->net, "intr status %d\n", status);
 206                 break;
 207         }
 208
 209         if (!netif_running (dev->net))
 210                 return;
 211
 212         status = usb_submit_urb (urb, GFP_ATOMIC);
 213         if (status != 0)
 214                 netif_err(dev, timer, dev->net,
 215                           "intr resubmit --> %d\n", status);
 216 }
 217
 218 static int init_status (struct usbnet *dev, struct usb_interface *intf)
 219 {
 220         char            *buf = NULL;
 221         unsigned        pipe = 0;
 222         unsigned        maxp;
 223         unsigned        period;
 224
 225         if (!dev->driver_info->status)
 226                 return 0;
 227
 228         pipe = usb_rcvintpipe (dev->udev,
 229                         dev->status->desc.bEndpointAddress
 230                                 & USB_ENDPOINT_NUMBER_MASK);
 231         maxp = usb_maxpacket (dev->udev, pipe, 0);
 232
 233         /* avoid 1 msec chatter:  min 8 msec poll rate */
 234         period = max ((int) dev->status->desc.bInterval,
 235                 (dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
 236
 237         buf = kmalloc (maxp, GFP_KERNEL);
 238         if (buf) {
 239                 dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
 240                 if (!dev->interrupt) {
 241                         kfree (buf);
 242                         return -ENOMEM;
 243                 } else {
 244                         usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
 245                                 buf, maxp, intr_complete, dev, period);
 246                         dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
 247                         dev_dbg(&intf->dev,
 248                                 "status ep%din, %d bytes period %d\n",
 249                                 usb_pipeendpoint(pipe), maxp, period);
 250                 }
 251         }
 252         return 0;
 253 }
 254
 255 /* Passes this packet up the stack, updating its accounting.
 256  * Some link protocols batch packets, so their rx_fixup paths
 257  * can return clones as well as just modify the original skb.
 258  */
 259 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
 260 {
 261         int     status;
 262
 263         if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
 264                 skb_queue_tail(&dev->rxq_pause, skb);
 265                 return;
 266         }
 267
 268         skb->protocol = eth_type_trans (skb, dev->net);
 269         dev->net->stats.rx_packets++;
 270         dev->net->stats.rx_bytes += skb->len;
 271
 272         netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
 273                   skb->len + sizeof (struct ethhdr), skb->protocol);
 274         memset (skb->cb, 0, sizeof (struct skb_data));
 275
 276         if (skb_defer_rx_timestamp(skb))
 277                 return;
 278
 279         status = netif_rx (skb);
 280         if (status != NET_RX_SUCCESS)
 281                 netif_dbg(dev, rx_err, dev->net,
 282                           "netif_rx status %d\n", status);
 283 }
 284 EXPORT_SYMBOL_GPL(usbnet_skb_return);
 285
 286 \f
 287 /*-------------------------------------------------------------------------
 288  *
 289  * Network Device Driver (peer link to "Host Device", from USB host)
 290  *
 291  *-------------------------------------------------------------------------*/
 292
 293 int usbnet_change_mtu (struct net_device *net, int new_mtu)
 294 {
 295         struct usbnet   *dev = netdev_priv(net);
 296         int             ll_mtu = new_mtu + net->hard_header_len;
 297         int             old_hard_mtu = dev->hard_mtu;
 298         int             old_rx_urb_size = dev->rx_urb_size;
 299
 300         if (new_mtu <= 0)
 301                 return -EINVAL;
 302         // no second zero-length packet read wanted after mtu-sized packets
 303         if ((ll_mtu % dev->maxpacket) == 0)
 304                 return -EDOM;
 305         net->mtu = new_mtu;
 306
 307         dev->hard_mtu = net->mtu + net->hard_header_len;
 308         if (dev->rx_urb_size == old_hard_mtu) {
 309                 dev->rx_urb_size = dev->hard_mtu;
 310                 if (dev->rx_urb_size > old_rx_urb_size)
 311                         usbnet_unlink_rx_urbs(dev);
 312         }
 313
 314         return 0;
 315 }
 316 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
 317
 318 /* The caller must hold list->lock */
 319 static void __usbnet_queue_skb(struct sk_buff_head *list,
 320                         struct sk_buff *newsk, enum skb_state state)
 321 {
 322         struct skb_data *entry = (struct skb_data *) newsk->cb;
 323
 324         __skb_queue_tail(list, newsk);
 325         entry->state = state;
 326 }
 327
 328 /*-------------------------------------------------------------------------*/
 329
 330 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
 331  * completion callbacks.  2.5 should have fixed those bugs...
 332  */
 333
 334 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
 335                 struct sk_buff_head *list, enum skb_state state)
 336 {
 337         unsigned long           flags;
 338         enum skb_state          old_state;
 339         struct skb_data *entry = (struct skb_data *) skb->cb;
 340
 341         spin_lock_irqsave(&list->lock, flags);
 342         old_state = entry->state;
 343         entry->state = state;
 344         __skb_unlink(skb, list);
 345         spin_unlock(&list->lock);
 346         spin_lock(&dev->done.lock);
 347         __skb_queue_tail(&dev->done, skb);
 348         if (dev->done.qlen == 1)
 349                 tasklet_schedule(&dev->bh);
 350         spin_unlock_irqrestore(&dev->done.lock, flags);
 351         return old_state;
 352 }
 353
 354 /* some work can't be done in tasklets, so we use keventd
 355  *
 356  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
 357  * but tasklet_schedule() doesn't.  hope the failure is rare.
 358  */
 359 void usbnet_defer_kevent (struct usbnet *dev, int work)
 360 {
 361         set_bit (work, &dev->flags);
 362         if (!schedule_work (&dev->kevent)) {
 363                 if (net_ratelimit())
 364                         netdev_err(dev->net, "kevent %d may have been dropped\n", work);
 365         } else {
 366                 netdev_dbg(dev->net, "kevent %d scheduled\n", work);
 367         }
 368 }
 369 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
 370
 371 /*-------------------------------------------------------------------------*/
 372
 373 static void rx_complete (struct urb *urb);
 374
 375 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
 376 {
 377         struct sk_buff          *skb;
 378         struct skb_data         *entry;
 379         int                     retval = 0;
 380         unsigned long           lockflags;
 381         size_t                  size = dev->rx_urb_size;
 382
 383         /* prevent rx skb allocation when error ratio is high */
 384         if (test_bit(EVENT_RX_KILL, &dev->flags)) {
 385                 usb_free_urb(urb);
 386                 return -ENOLINK;
 387         }
 388
 389         skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
 390         if (!skb) {
 391                 netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
 392                 usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
 393                 usb_free_urb (urb);
 394                 return -ENOMEM;
 395         }
 396
 397         entry = (struct skb_data *) skb->cb;
 398         entry->urb = urb;
 399         entry->dev = dev;
 400         entry->length = 0;
 401
 402         usb_fill_bulk_urb (urb, dev->udev, dev->in,
 403                 skb->data, size, rx_complete, skb);
 404
 405         spin_lock_irqsave (&dev->rxq.lock, lockflags);
 406
 407         if (netif_running (dev->net) &&
 408             netif_device_present (dev->net) &&
 409             !test_bit (EVENT_RX_HALT, &dev->flags) &&
 410             !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
 411                 switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
 412                 case -EPIPE:
 413                         usbnet_defer_kevent (dev, EVENT_RX_HALT);
 414                         break;
 415                 case -ENOMEM:
 416                         usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
 417                         break;
 418                 case -ENODEV:
 419                         netif_dbg(dev, ifdown, dev->net, "device gone\n");
 420                         netif_device_detach (dev->net);
 421                         break;
 422                 case -EHOSTUNREACH:
 423                         retval = -ENOLINK;
 424                         break;
 425                 default:
 426                         netif_dbg(dev, rx_err, dev->net,
 427                                   "rx submit, %d\n", retval);
 428                         tasklet_schedule (&dev->bh);
 429                         break;
 430                 case 0:
 431                         __usbnet_queue_skb(&dev->rxq, skb, rx_start);
 432                 }
 433         } else {
 434                 netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
 435                 retval = -ENOLINK;
 436         }
 437         spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
 438         if (retval) {
 439                 dev_kfree_skb_any (skb);
 440                 usb_free_urb (urb);
 441         }
 442         return retval;
 443 }
 444
 445
 446 /*-------------------------------------------------------------------------*/
 447
 448 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
 449 {
 450         if (dev->driver_info->rx_fixup &&
 451             !dev->driver_info->rx_fixup (dev, skb)) {
 452                 /* With RX_ASSEMBLE, rx_fixup() must update counters */
 453                 if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
 454                         dev->net->stats.rx_errors++;
 455                 goto done;
 456         }
 457         // else network stack removes extra byte if we forced a short packet
 458
 459         if (skb->len) {
 460                 /* all data was already cloned from skb inside the driver */
 461                 if (dev->driver_info->flags & FLAG_MULTI_PACKET)
 462                         dev_kfree_skb_any(skb);
 463                 else
 464                         usbnet_skb_return(dev, skb);
 465                 return;
 466         }
 467
 468         netif_dbg(dev, rx_err, dev->net, "drop\n");
 469         dev->net->stats.rx_errors++;
 470 done:
 471         skb_queue_tail(&dev->done, skb);
 472 }
 473
 474 /*-------------------------------------------------------------------------*/
 475
 476 static void rx_complete (struct urb *urb)
 477 {
 478         struct sk_buff          *skb = (struct sk_buff *) urb->context;
 479         struct skb_data         *entry = (struct skb_data *) skb->cb;
 480         struct usbnet           *dev = entry->dev;
 481         int                     urb_status = urb->status;
 482         enum skb_state          state;
 483
 484         skb_put (skb, urb->actual_length);
 485         state = rx_done;
 486         entry->urb = NULL;
 487
 488         switch (urb_status) {
 489         /* success */
 490         case 0:
 491                 if (skb->len < dev->net->hard_header_len) {
 492                         state = rx_cleanup;
 493                         dev->net->stats.rx_errors++;
 494                         dev->net->stats.rx_length_errors++;
 495                         netif_dbg(dev, rx_err, dev->net,
 496                                   "rx length %d\n", skb->len);
 497                 }
 498                 break;
 499
 500         /* stalls need manual reset. this is rare ... except that
 501          * when going through USB 2.0 TTs, unplug appears this way.
 502          * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
 503          * storm, recovering as needed.
 504          */
 505         case -EPIPE:
 506                 dev->net->stats.rx_errors++;
 507                 usbnet_defer_kevent (dev, EVENT_RX_HALT);
 508                 // FALLTHROUGH
 509
 510         /* software-driven interface shutdown */
 511         case -ECONNRESET:               /* async unlink */
 512         case -ESHUTDOWN:                /* hardware gone */
 513                 netif_dbg(dev, ifdown, dev->net,
 514                           "rx shutdown, code %d\n", urb_status);
 515                 goto block;
 516
 517         /* we get controller i/o faults during khubd disconnect() delays.
 518          * throttle down resubmits, to avoid log floods; just temporarily,
 519          * so we still recover when the fault isn't a khubd delay.
 520          */
 521         case -EPROTO:
 522         case -ETIME:
 523         case -EILSEQ:
 524                 dev->net->stats.rx_errors++;
 525                 if (!timer_pending (&dev->delay)) {
 526                         mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
 527                         netif_dbg(dev, link, dev->net,
 528                                   "rx throttle %d\n", urb_status);
 529                 }
 530 block:
 531                 state = rx_cleanup;
 532                 entry->urb = urb;
 533                 urb = NULL;
 534                 break;
 535
 536         /* data overrun ... flush fifo? */
 537         case -EOVERFLOW:
 538                 dev->net->stats.rx_over_errors++;
 539                 // FALLTHROUGH
 540
 541         default:
 542                 state = rx_cleanup;
 543                 dev->net->stats.rx_errors++;
 544                 netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
 545                 break;
 546         }
 547
 548         /* stop rx if packet error rate is high */
 549         if (++dev->pkt_cnt > 30) {
 550                 dev->pkt_cnt = 0;
 551                 dev->pkt_err = 0;
 552         } else {
 553                 if (state == rx_cleanup)
 554                         dev->pkt_err++;
 555                 if (dev->pkt_err > 20)
 556                         set_bit(EVENT_RX_KILL, &dev->flags);
 557         }
 558
 559         state = defer_bh(dev, skb, &dev->rxq, state);
 560
 561         if (urb) {
 562                 if (netif_running (dev->net) &&
 563                     !test_bit (EVENT_RX_HALT, &dev->flags) &&
 564                     state != unlink_start) {
 565                         rx_submit (dev, urb, GFP_ATOMIC);
 566                         usb_mark_last_busy(dev->udev);
 567                         return;
 568                 }
 569                 usb_free_urb (urb);
 570         }
 571         netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
 572 }
 573
 574 /*-------------------------------------------------------------------------*/
 575 void usbnet_pause_rx(struct usbnet *dev)
 576 {
 577         set_bit(EVENT_RX_PAUSED, &dev->flags);
 578
 579         netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
 580 }
 581 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
 582
 583 void usbnet_resume_rx(struct usbnet *dev)
 584 {
 585         struct sk_buff *skb;
 586         int num = 0;
 587
 588         clear_bit(EVENT_RX_PAUSED, &dev->flags);
 589
 590         while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
 591                 usbnet_skb_return(dev, skb);
 592                 num++;
 593         }
 594
 595         tasklet_schedule(&dev->bh);
 596
 597         netif_dbg(dev, rx_status, dev->net,
 598                   "paused rx queue disabled, %d skbs requeued\n", num);
 599 }
 600 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
 601
 602 void usbnet_purge_paused_rxq(struct usbnet *dev)
 603 {
 604         skb_queue_purge(&dev->rxq_pause);
 605 }
 606 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
 607
 608 /*-------------------------------------------------------------------------*/
 609
 610 // unlink pending rx/tx; completion handlers do all other cleanup
 611
 612 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
 613 {
 614         unsigned long           flags;
 615         struct sk_buff          *skb;
 616         int                     count = 0;
 617
 618         spin_lock_irqsave (&q->lock, flags);
 619         while (!skb_queue_empty(q)) {
 620                 struct skb_data         *entry;
 621                 struct urb              *urb;
 622                 int                     retval;
 623
 624                 skb_queue_walk(q, skb) {
 625                         entry = (struct skb_data *) skb->cb;
 626                         if (entry->state != unlink_start)
 627                                 goto found;
 628                 }
 629                 break;
 630 found:
 631                 entry->state = unlink_start;
 632                 urb = entry->urb;
 633
 634                 /*
 635                  * Get reference count of the URB to avoid it to be
 636                  * freed during usb_unlink_urb, which may trigger
 637                  * use-after-free problem inside usb_unlink_urb since
 638                  * usb_unlink_urb is always racing with .complete
 639                  * handler(include defer_bh).
 640                  */
 641                 usb_get_urb(urb);
 642                 spin_unlock_irqrestore(&q->lock, flags);
 643                 // during some PM-driven resume scenarios,
 644                 // these (async) unlinks complete immediately
 645                 retval = usb_unlink_urb (urb);
 646                 if (retval != -EINPROGRESS && retval != 0)
 647                         netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
 648                 else
 649                         count++;
 650                 usb_put_urb(urb);
 651                 spin_lock_irqsave(&q->lock, flags);
 652         }
 653         spin_unlock_irqrestore (&q->lock, flags);
 654         return count;
 655 }
 656
 657 // Flush all pending rx urbs
 658 // minidrivers may need to do this when the MTU changes
 659
 660 void usbnet_unlink_rx_urbs(struct usbnet *dev)
 661 {
 662         if (netif_running(dev->net)) {
 663                 (void) unlink_urbs (dev, &dev->rxq);
 664                 tasklet_schedule(&dev->bh);
 665         }
 666 }
 667 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
 668
 669 /*-------------------------------------------------------------------------*/
 670
 671 // precondition: never called in_interrupt
 672 static void usbnet_terminate_urbs(struct usbnet *dev)
 673 {
 674         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
 675         DECLARE_WAITQUEUE(wait, current);
 676         int temp;
 677
 678         /* ensure there are no more active urbs */
 679         add_wait_queue(&unlink_wakeup, &wait);
 680         set_current_state(TASK_UNINTERRUPTIBLE);
 681         dev->wait = &unlink_wakeup;
 682         temp = unlink_urbs(dev, &dev->txq) +
 683                 unlink_urbs(dev, &dev->rxq);
 684
 685         /* maybe wait for deletions to finish. */
 686         while (!skb_queue_empty(&dev->rxq)
 687                 && !skb_queue_empty(&dev->txq)
 688                 && !skb_queue_empty(&dev->done)) {
 689                         schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
 690                         set_current_state(TASK_UNINTERRUPTIBLE);
 691                         netif_dbg(dev, ifdown, dev->net,
 692                                   "waited for %d urb completions\n", temp);
 693         }
 694         set_current_state(TASK_RUNNING);
 695         dev->wait = NULL;
 696         remove_wait_queue(&unlink_wakeup, &wait);
 697 }
 698
 699 int usbnet_stop (struct net_device *net)
 700 {
 701         struct usbnet           *dev = netdev_priv(net);
 702         struct driver_info      *info = dev->driver_info;
 703         int                     retval;
 704
 705         clear_bit(EVENT_DEV_OPEN, &dev->flags);
 706         netif_stop_queue (net);
 707
 708         netif_info(dev, ifdown, dev->net,
 709                    "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
 710                    net->stats.rx_packets, net->stats.tx_packets,
 711                    net->stats.rx_errors, net->stats.tx_errors);
 712
 713         /* allow minidriver to stop correctly (wireless devices to turn off
 714          * radio etc) */
 715         if (info->stop) {
 716                 retval = info->stop(dev);
 717                 if (retval < 0)
 718                         netif_info(dev, ifdown, dev->net,
 719                                    "stop fail (%d) usbnet usb-%s-%s, %s\n",
 720                                    retval,
 721                                    dev->udev->bus->bus_name, dev->udev->devpath,
 722                                    info->description);
 723         }
 724
 725         if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
 726                 usbnet_terminate_urbs(dev);
 727
 728         usb_kill_urb(dev->interrupt);
 729
 730         usbnet_purge_paused_rxq(dev);
 731
 732         /* deferred work (task, timer, softirq) must also stop.
 733          * can't flush_scheduled_work() until we drop rtnl (later),
 734          * else workers could deadlock; so make workers a NOP.
 735          */
 736         dev->flags = 0;
 737         del_timer_sync (&dev->delay);
 738         tasklet_kill (&dev->bh);
 739         if (info->manage_power &&
 740             !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags))
 741                 info->manage_power(dev, 0);
 742         else
 743                 usb_autopm_put_interface(dev->intf);
 744
 745         return 0;
 746 }
 747 EXPORT_SYMBOL_GPL(usbnet_stop);
 748
 749 /*-------------------------------------------------------------------------*/
 750
 751 // posts reads, and enables write queuing
 752
 753 // precondition: never called in_interrupt
 754
 755 int usbnet_open (struct net_device *net)
 756 {
 757         struct usbnet           *dev = netdev_priv(net);
 758         int                     retval;
 759         struct driver_info      *info = dev->driver_info;
 760
 761         if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
 762                 netif_info(dev, ifup, dev->net,
 763                            "resumption fail (%d) usbnet usb-%s-%s, %s\n",
 764                            retval,
 765                            dev->udev->bus->bus_name,
 766                            dev->udev->devpath,
 767                            info->description);
 768                 goto done_nopm;
 769         }
 770
 771         // put into "known safe" state
 772         if (info->reset && (retval = info->reset (dev)) < 0) {
 773                 netif_info(dev, ifup, dev->net,
 774                            "open reset fail (%d) usbnet usb-%s-%s, %s\n",
 775                            retval,
 776                            dev->udev->bus->bus_name,
 777                            dev->udev->devpath,
 778                            info->description);
 779                 goto done;
 780         }
 781
 782         // insist peer be connected
 783         if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
 784                 netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
 785                 goto done;
 786         }
 787
 788         /* start any status interrupt transfer */
 789         if (dev->interrupt) {
 790                 retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
 791                 if (retval < 0) {
 792                         netif_err(dev, ifup, dev->net,
 793                                   "intr submit %d\n", retval);
 794                         goto done;
 795                 }
 796         }
 797
 798         set_bit(EVENT_DEV_OPEN, &dev->flags);
 799         netif_start_queue (net);
 800         netif_info(dev, ifup, dev->net,
 801                    "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
 802                    (int)RX_QLEN(dev), (int)TX_QLEN(dev),
 803                    dev->net->mtu,
 804                    (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
 805                    (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
 806                    (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
 807                    (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
 808                    (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
 809                    "simple");
 810
 811         /* reset rx error state */
 812         dev->pkt_cnt = 0;
 813         dev->pkt_err = 0;
 814         clear_bit(EVENT_RX_KILL, &dev->flags);
 815
 816         // delay posting reads until we're fully open
 817         tasklet_schedule (&dev->bh);
 818         if (info->manage_power) {
 819                 retval = info->manage_power(dev, 1);
 820                 if (retval < 0) {
 821                         retval = 0;
 822                         set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
 823                 } else {
 824                         usb_autopm_put_interface(dev->intf);
 825                 }
 826         }
 827         return retval;
 828 done:
 829         usb_autopm_put_interface(dev->intf);
 830 done_nopm:
 831         return retval;
 832 }
 833 EXPORT_SYMBOL_GPL(usbnet_open);
 834
 835 /*-------------------------------------------------------------------------*/
 836
 837 /* ethtool methods; minidrivers may need to add some more, but
 838  * they'll probably want to use this base set.
 839  */
 840
 841 int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
 842 {
 843         struct usbnet *dev = netdev_priv(net);
 844
 845         if (!dev->mii.mdio_read)
 846                 return -EOPNOTSUPP;
 847
 848         return mii_ethtool_gset(&dev->mii, cmd);
 849 }
 850 EXPORT_SYMBOL_GPL(usbnet_get_settings);
 851
 852 int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
 853 {
 854         struct usbnet *dev = netdev_priv(net);
 855         int retval;
 856
 857         if (!dev->mii.mdio_write)
 858                 return -EOPNOTSUPP;
 859
 860         retval = mii_ethtool_sset(&dev->mii, cmd);
 861
 862         /* link speed/duplex might have changed */
 863         if (dev->driver_info->link_reset)
 864                 dev->driver_info->link_reset(dev);
 865
 866         return retval;
 867
 868 }
 869 EXPORT_SYMBOL_GPL(usbnet_set_settings);
 870
 871 u32 usbnet_get_link (struct net_device *net)
 872 {
 873         struct usbnet *dev = netdev_priv(net);
 874
 875         /* If a check_connect is defined, return its result */
 876         if (dev->driver_info->check_connect)
 877                 return dev->driver_info->check_connect (dev) == 0;
 878
 879         /* if the device has mii operations, use those */
 880         if (dev->mii.mdio_read)
 881                 return mii_link_ok(&dev->mii);
 882
 883         /* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
 884         return ethtool_op_get_link(net);
 885 }
 886 EXPORT_SYMBOL_GPL(usbnet_get_link);
 887
 888 int usbnet_nway_reset(struct net_device *net)
 889 {
 890         struct usbnet *dev = netdev_priv(net);
 891
 892         if (!dev->mii.mdio_write)
 893                 return -EOPNOTSUPP;
 894
 895         return mii_nway_restart(&dev->mii);
 896 }
 897 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
 898
 899 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
 900 {
 901         struct usbnet *dev = netdev_priv(net);
 902
 903         strlcpy (info->driver, dev->driver_name, sizeof info->driver);
 904         strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
 905         strlcpy (info->fw_version, dev->driver_info->description,
 906                 sizeof info->fw_version);
 907         usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
 908 }
 909 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
 910
 911 u32 usbnet_get_msglevel (struct net_device *net)
 912 {
 913         struct usbnet *dev = netdev_priv(net);
 914
 915         return dev->msg_enable;
 916 }
 917 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
 918
 919 void usbnet_set_msglevel (struct net_device *net, u32 level)
 920 {
 921         struct usbnet *dev = netdev_priv(net);
 922
 923         dev->msg_enable = level;
 924 }
 925 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
 926
 927 /* drivers may override default ethtool_ops in their bind() routine */
 928 static const struct ethtool_ops usbnet_ethtool_ops = {
 929         .get_settings           = usbnet_get_settings,
 930         .set_settings           = usbnet_set_settings,
 931         .get_link               = usbnet_get_link,
 932         .nway_reset             = usbnet_nway_reset,
 933         .get_drvinfo            = usbnet_get_drvinfo,
 934         .get_msglevel           = usbnet_get_msglevel,
 935         .set_msglevel           = usbnet_set_msglevel,
 936         .get_ts_info            = ethtool_op_get_ts_info,
 937 };
 938
 939 /*-------------------------------------------------------------------------*/
 940
 941 static void __handle_link_change(struct usbnet *dev)
 942 {
 943         if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
 944                 return;
 945
 946         if (!netif_carrier_ok(dev->net)) {
 947                 /* kill URBs for reading packets to save bus bandwidth */
 948                 unlink_urbs(dev, &dev->rxq);
 949
 950                 /*
 951                  * tx_timeout will unlink URBs for sending packets and
 952                  * tx queue is stopped by netcore after link becomes off
 953                  */
 954         } else {
 955                 /* submitting URBs for reading packets */
 956                 tasklet_schedule(&dev->bh);
 957         }
 958
 959         clear_bit(EVENT_LINK_CHANGE, &dev->flags);
 960 }
 961
 962 /* work that cannot be done in interrupt context uses keventd.
 963  *
 964  * NOTE:  with 2.5 we could do more of this using completion callbacks,
 965  * especially now that control transfers can be queued.
 966  */
 967 static void
 968 kevent (struct work_struct *work)
 969 {
 970         struct usbnet           *dev =
 971                 container_of(work, struct usbnet, kevent);
 972         int                     status;
 973
 974         /* usb_clear_halt() needs a thread context */
 975         if (test_bit (EVENT_TX_HALT, &dev->flags)) {
 976                 unlink_urbs (dev, &dev->txq);
 977                 status = usb_autopm_get_interface(dev->intf);
 978                 if (status < 0)
 979                         goto fail_pipe;
 980                 status = usb_clear_halt (dev->udev, dev->out);
 981                 usb_autopm_put_interface(dev->intf);
 982                 if (status < 0 &&
 983                     status != -EPIPE &&
 984                     status != -ESHUTDOWN) {
 985                         if (netif_msg_tx_err (dev))
 986 fail_pipe:
 987                                 netdev_err(dev->net, "can't clear tx halt, status %d\n",
 988                                            status);
 989                 } else {
 990                         clear_bit (EVENT_TX_HALT, &dev->flags);
 991                         if (status != -ESHUTDOWN)
 992                                 netif_wake_queue (dev->net);
 993                 }
 994         }
 995         if (test_bit (EVENT_RX_HALT, &dev->flags)) {
 996                 unlink_urbs (dev, &dev->rxq);
 997                 status = usb_autopm_get_interface(dev->intf);
 998                 if (status < 0)
 999                         goto fail_halt;
1000                 status = usb_clear_halt (dev->udev, dev->in);
1001                 usb_autopm_put_interface(dev->intf);
1002                 if (status < 0 &&
1003                     status != -EPIPE &&
1004                     status != -ESHUTDOWN) {
1005                         if (netif_msg_rx_err (dev))
1006 fail_halt:
1007                                 netdev_err(dev->net, "can't clear rx halt, status %d\n",
1008                                            status);
1009                 } else {
1010                         clear_bit (EVENT_RX_HALT, &dev->flags);
1011                         tasklet_schedule (&dev->bh);
1012                 }
1013         }
1014
1015         /* tasklet could resubmit itself forever if memory is tight */
1016         if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1017                 struct urb      *urb = NULL;
1018                 int resched = 1;
1019
1020                 if (netif_running (dev->net))
1021                         urb = usb_alloc_urb (0, GFP_KERNEL);
1022                 else
1023                         clear_bit (EVENT_RX_MEMORY, &dev->flags);
1024                 if (urb != NULL) {
1025                         clear_bit (EVENT_RX_MEMORY, &dev->flags);
1026                         status = usb_autopm_get_interface(dev->intf);
1027                         if (status < 0) {
1028                                 usb_free_urb(urb);
1029                                 goto fail_lowmem;
1030                         }
1031                         if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1032                                 resched = 0;
1033                         usb_autopm_put_interface(dev->intf);
1034 fail_lowmem:
1035                         if (resched)
1036                                 tasklet_schedule (&dev->bh);
1037                 }
1038         }
1039
1040         if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1041                 struct driver_info      *info = dev->driver_info;
1042                 int                     retval = 0;
1043
1044                 clear_bit (EVENT_LINK_RESET, &dev->flags);
1045                 status = usb_autopm_get_interface(dev->intf);
1046                 if (status < 0)
1047                         goto skip_reset;
1048                 if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1049                         usb_autopm_put_interface(dev->intf);
1050 skip_reset:
1051                         netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1052                                     retval,
1053                                     dev->udev->bus->bus_name,
1054                                     dev->udev->devpath,
1055                                     info->description);
1056                 } else {
1057                         usb_autopm_put_interface(dev->intf);
1058                 }
1059
1060                 /* handle link change from link resetting */
1061                 __handle_link_change(dev);
1062         }
1063
1064         if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1065                 __handle_link_change(dev);
1066
1067         if (dev->flags)
1068                 netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1069 }
1070
1071 /*-------------------------------------------------------------------------*/
1072
1073 static void tx_complete (struct urb *urb)
1074 {
1075         struct sk_buff          *skb = (struct sk_buff *) urb->context;
1076         struct skb_data         *entry = (struct skb_data *) skb->cb;
1077         struct usbnet           *dev = entry->dev;
1078
1079         if (urb->status == 0) {
1080                 if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
1081                         dev->net->stats.tx_packets++;
1082                 dev->net->stats.tx_bytes += entry->length;
1083         } else {
1084                 dev->net->stats.tx_errors++;
1085
1086                 switch (urb->status) {
1087                 case -EPIPE:
1088                         usbnet_defer_kevent (dev, EVENT_TX_HALT);
1089                         break;
1090
1091                 /* software-driven interface shutdown */
1092                 case -ECONNRESET:               // async unlink
1093                 case -ESHUTDOWN:                // hardware gone
1094                         break;
1095
1096                 // like rx, tx gets controller i/o faults during khubd delays
1097                 // and so it uses the same throttling mechanism.
1098                 case -EPROTO:
1099                 case -ETIME:
1100                 case -EILSEQ:
1101                         usb_mark_last_busy(dev->udev);
1102                         if (!timer_pending (&dev->delay)) {
1103                                 mod_timer (&dev->delay,
1104                                         jiffies + THROTTLE_JIFFIES);
1105                                 netif_dbg(dev, link, dev->net,
1106                                           "tx throttle %d\n", urb->status);
1107                         }
1108                         netif_stop_queue (dev->net);
1109                         break;
1110                 default:
1111                         netif_dbg(dev, tx_err, dev->net,
1112                                   "tx err %d\n", entry->urb->status);
1113                         break;
1114                 }
1115         }
1116
1117         usb_autopm_put_interface_async(dev->intf);
1118         (void) defer_bh(dev, skb, &dev->txq, tx_done);
1119 }
1120
1121 /*-------------------------------------------------------------------------*/
1122
1123 void usbnet_tx_timeout (struct net_device *net)
1124 {
1125         struct usbnet           *dev = netdev_priv(net);
1126
1127         unlink_urbs (dev, &dev->txq);
1128         tasklet_schedule (&dev->bh);
1129
1130         // FIXME: device recovery -- reset?
1131 }
1132 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1133
1134 /*-------------------------------------------------------------------------*/
1135
1136 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1137                                      struct net_device *net)
1138 {
1139         struct usbnet           *dev = netdev_priv(net);
1140         int                     length;
1141         struct urb              *urb = NULL;
1142         struct skb_data         *entry;
1143         struct driver_info      *info = dev->driver_info;
1144         unsigned long           flags;
1145         int retval;
1146
1147         if (skb)
1148                 skb_tx_timestamp(skb);
1149
1150         // some devices want funky USB-level framing, for
1151         // win32 driver (usually) and/or hardware quirks
1152         if (info->tx_fixup) {
1153                 skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1154                 if (!skb) {
1155                         /* packet collected; minidriver waiting for more */
1156                         if (info->flags & FLAG_MULTI_PACKET)
1157                                 goto not_drop;
1158                         netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1159                         goto drop;
1160                 }
1161         }
1162         length = skb->len;
1163
1164         if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1165                 netif_dbg(dev, tx_err, dev->net, "no urb\n");
1166                 goto drop;
1167         }
1168
1169         entry = (struct skb_data *) skb->cb;
1170         entry->urb = urb;
1171         entry->dev = dev;
1172         entry->length = length;
1173
1174         usb_fill_bulk_urb (urb, dev->udev, dev->out,
1175                         skb->data, skb->len, tx_complete, skb);
1176
1177         /* don't assume the hardware handles USB_ZERO_PACKET
1178          * NOTE:  strictly conforming cdc-ether devices should expect
1179          * the ZLP here, but ignore the one-byte packet.
1180          * NOTE2: CDC NCM specification is different from CDC ECM when
1181          * handling ZLP/short packets, so cdc_ncm driver will make short
1182          * packet itself if needed.
1183          */
1184         if (length % dev->maxpacket == 0) {
1185                 if (!(info->flags & FLAG_SEND_ZLP)) {
1186                         if (!(info->flags & FLAG_MULTI_PACKET)) {
1187                                 urb->transfer_buffer_length++;
1188                                 if (skb_tailroom(skb)) {
1189                                         skb->data[skb->len] = 0;
1190                                         __skb_put(skb, 1);
1191                                 }
1192                         }
1193                 } else
1194                         urb->transfer_flags |= URB_ZERO_PACKET;
1195         }
1196
1197         spin_lock_irqsave(&dev->txq.lock, flags);
1198         retval = usb_autopm_get_interface_async(dev->intf);
1199         if (retval < 0) {
1200                 spin_unlock_irqrestore(&dev->txq.lock, flags);
1201                 goto drop;
1202         }
1203
1204 #ifdef CONFIG_PM
1205         /* if this triggers the device is still a sleep */
1206         if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1207                 /* transmission will be done in resume */
1208                 usb_anchor_urb(urb, &dev->deferred);
1209                 /* no use to process more packets */
1210                 netif_stop_queue(net);
1211                 usb_put_urb(urb);
1212                 spin_unlock_irqrestore(&dev->txq.lock, flags);
1213                 netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1214                 goto deferred;
1215         }
1216 #endif
1217
1218         switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1219         case -EPIPE:
1220                 netif_stop_queue (net);
1221                 usbnet_defer_kevent (dev, EVENT_TX_HALT);
1222                 usb_autopm_put_interface_async(dev->intf);
1223                 break;
1224         default:
1225                 usb_autopm_put_interface_async(dev->intf);
1226                 netif_dbg(dev, tx_err, dev->net,
1227                           "tx: submit urb err %d\n", retval);
1228                 break;
1229         case 0:
1230                 net->trans_start = jiffies;
1231                 __usbnet_queue_skb(&dev->txq, skb, tx_start);
1232                 if (dev->txq.qlen >= TX_QLEN (dev))
1233                         netif_stop_queue (net);
1234         }
1235         spin_unlock_irqrestore (&dev->txq.lock, flags);
1236
1237         if (retval) {
1238                 netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1239 drop:
1240                 dev->net->stats.tx_dropped++;
1241 not_drop:
1242                 if (skb)
1243                         dev_kfree_skb_any (skb);
1244                 usb_free_urb (urb);
1245         } else
1246                 netif_dbg(dev, tx_queued, dev->net,
1247                           "> tx, len %d, type 0x%x\n", length, skb->protocol);
1248 #ifdef CONFIG_PM
1249 deferred:
1250 #endif
1251         return NETDEV_TX_OK;
1252 }
1253 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1254
1255 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1256 {
1257         struct urb      *urb;
1258         int             i;
1259         int             ret = 0;
1260
1261         /* don't refill the queue all at once */
1262         for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1263                 urb = usb_alloc_urb(0, flags);
1264                 if (urb != NULL) {
1265                         ret = rx_submit(dev, urb, flags);
1266                         if (ret)
1267                                 goto err;
1268                 } else {
1269                         ret = -ENOMEM;
1270                         goto err;
1271                 }
1272         }
1273 err:
1274         return ret;
1275 }
1276
1277 /*-------------------------------------------------------------------------*/
1278
1279 // tasklet (work deferred from completions, in_irq) or timer
1280
1281 static void usbnet_bh (unsigned long param)
1282 {
1283         struct usbnet           *dev = (struct usbnet *) param;
1284         struct sk_buff          *skb;
1285         struct skb_data         *entry;
1286
1287         while ((skb = skb_dequeue (&dev->done))) {
1288                 entry = (struct skb_data *) skb->cb;
1289                 switch (entry->state) {
1290                 case rx_done:
1291                         entry->state = rx_cleanup;
1292                         rx_process (dev, skb);
1293                         continue;
1294                 case tx_done:
1295                 case rx_cleanup:
1296                         usb_free_urb (entry->urb);
1297                         dev_kfree_skb (skb);
1298                         continue;
1299                 default:
1300                         netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1301                 }
1302         }
1303
1304         /* restart RX again after disabling due to high error rate */
1305         clear_bit(EVENT_RX_KILL, &dev->flags);
1306
1307         // waiting for all pending urbs to complete?
1308         if (dev->wait) {
1309                 if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
1310                         wake_up (dev->wait);
1311                 }
1312
1313         // or are we maybe short a few urbs?
1314         } else if (netif_running (dev->net) &&
1315                    netif_device_present (dev->net) &&
1316                    netif_carrier_ok(dev->net) &&
1317                    !timer_pending (&dev->delay) &&
1318                    !test_bit (EVENT_RX_HALT, &dev->flags)) {
1319                 int     temp = dev->rxq.qlen;
1320
1321                 if (temp < RX_QLEN(dev)) {
1322                         if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1323                                 return;
1324                         if (temp != dev->rxq.qlen)
1325                                 netif_dbg(dev, link, dev->net,
1326                                           "rxqlen %d --> %d\n",
1327                                           temp, dev->rxq.qlen);
1328                         if (dev->rxq.qlen < RX_QLEN(dev))
1329                                 tasklet_schedule (&dev->bh);
1330                 }
1331                 if (dev->txq.qlen < TX_QLEN (dev))
1332                         netif_wake_queue (dev->net);
1333         }
1334 }
1335
1336
1337 /*-------------------------------------------------------------------------
1338  *
1339  * USB Device Driver support
1340  *
1341  *-------------------------------------------------------------------------*/
1342
1343 // precondition: never called in_interrupt
1344
1345 void usbnet_disconnect (struct usb_interface *intf)
1346 {
1347         struct usbnet           *dev;
1348         struct usb_device       *xdev;
1349         struct net_device       *net;
1350
1351         dev = usb_get_intfdata(intf);
1352         usb_set_intfdata(intf, NULL);
1353         if (!dev)
1354                 return;
1355
1356         xdev = interface_to_usbdev (intf);
1357
1358         netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1359                    intf->dev.driver->name,
1360                    xdev->bus->bus_name, xdev->devpath,
1361                    dev->driver_info->description);
1362
1363         net = dev->net;
1364         unregister_netdev (net);
1365
1366         cancel_work_sync(&dev->kevent);
1367
1368         usb_scuttle_anchored_urbs(&dev->deferred);
1369
1370         if (dev->driver_info->unbind)
1371                 dev->driver_info->unbind (dev, intf);
1372
1373         usb_kill_urb(dev->interrupt);
1374         usb_free_urb(dev->interrupt);
1375
1376         free_netdev(net);
1377 }
1378 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1379
1380 static const struct net_device_ops usbnet_netdev_ops = {
1381         .ndo_open               = usbnet_open,
1382         .ndo_stop               = usbnet_stop,
1383         .ndo_start_xmit         = usbnet_start_xmit,
1384         .ndo_tx_timeout         = usbnet_tx_timeout,
1385         .ndo_change_mtu         = usbnet_change_mtu,
1386         .ndo_set_mac_address    = eth_mac_addr,
1387         .ndo_validate_addr      = eth_validate_addr,
1388 };
1389
1390 /*-------------------------------------------------------------------------*/
1391
1392 // precondition: never called in_interrupt
1393
1394 static struct device_type wlan_type = {
1395         .name   = "wlan",
1396 };
1397
1398 static struct device_type wwan_type = {
1399         .name   = "wwan",
1400 };
1401
1402 int
1403 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1404 {
1405         struct usbnet                   *dev;
1406         struct net_device               *net;
1407         struct usb_host_interface       *interface;
1408         struct driver_info              *info;
1409         struct usb_device               *xdev;
1410         int                             status;
1411         const char                      *name;
1412         struct usb_driver       *driver = to_usb_driver(udev->dev.driver);
1413
1414         /* usbnet already took usb runtime pm, so have to enable the feature
1415          * for usb interface, otherwise usb_autopm_get_interface may return
1416          * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
1417          */
1418         if (!driver->supports_autosuspend) {
1419                 driver->supports_autosuspend = 1;
1420                 pm_runtime_enable(&udev->dev);
1421         }
1422
1423         name = udev->dev.driver->name;
1424         info = (struct driver_info *) prod->driver_info;
1425         if (!info) {
1426                 dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1427                 return -ENODEV;
1428         }
1429         xdev = interface_to_usbdev (udev);
1430         interface = udev->cur_altsetting;
1431
1432         status = -ENOMEM;
1433
1434         // set up our own records
1435         net = alloc_etherdev(sizeof(*dev));
1436         if (!net)
1437                 goto out;
1438
1439         /* netdev_printk() needs this so do it as early as possible */
1440         SET_NETDEV_DEV(net, &udev->dev);
1441
1442         dev = netdev_priv(net);
1443         dev->udev = xdev;
1444         dev->intf = udev;
1445         dev->driver_info = info;
1446         dev->driver_name = name;
1447         dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1448                                 | NETIF_MSG_PROBE | NETIF_MSG_LINK);
1449         skb_queue_head_init (&dev->rxq);
1450         skb_queue_head_init (&dev->txq);
1451         skb_queue_head_init (&dev->done);
1452         skb_queue_head_init(&dev->rxq_pause);
1453         dev->bh.func = usbnet_bh;
1454         dev->bh.data = (unsigned long) dev;
1455         INIT_WORK (&dev->kevent, kevent);
1456         init_usb_anchor(&dev->deferred);
1457         dev->delay.function = usbnet_bh;
1458         dev->delay.data = (unsigned long) dev;
1459         init_timer (&dev->delay);
1460         mutex_init (&dev->phy_mutex);
1461
1462         dev->net = net;
1463         strcpy (net->name, "usb%d");
1464         memcpy (net->dev_addr, node_id, sizeof node_id);
1465
1466         /* rx and tx sides can use different message sizes;
1467          * bind() should set rx_urb_size in that case.
1468          */
1469         dev->hard_mtu = net->mtu + net->hard_header_len;
1470 #if 0
1471 // dma_supported() is deeply broken on almost all architectures
1472         // possible with some EHCI controllers
1473         if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
1474                 net->features |= NETIF_F_HIGHDMA;
1475 #endif
1476
1477         net->netdev_ops = &usbnet_netdev_ops;
1478         net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1479         net->ethtool_ops = &usbnet_ethtool_ops;
1480
1481         // allow device-specific bind/init procedures
1482         // NOTE net->name still not usable ...
1483         if (info->bind) {
1484                 status = info->bind (dev, udev);
1485                 if (status < 0)
1486                         goto out1;
1487
1488                 // heuristic:  "usb%d" for links we know are two-host,
1489                 // else "eth%d" when there's reasonable doubt.  userspace
1490                 // can rename the link if it knows better.
1491                 if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1492                     ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1493                      (net->dev_addr [0] & 0x02) == 0))
1494                         strcpy (net->name, "eth%d");
1495                 /* WLAN devices should always be named "wlan%d" */
1496                 if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1497                         strcpy(net->name, "wlan%d");
1498                 /* WWAN devices should always be named "wwan%d" */
1499                 if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1500                         strcpy(net->name, "wwan%d");
1501
1502                 /* devices that cannot do ARP */
1503                 if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1504                         net->flags |= IFF_NOARP;
1505
1506                 /* maybe the remote can't receive an Ethernet MTU */
1507                 if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1508                         net->mtu = dev->hard_mtu - net->hard_header_len;
1509         } else if (!info->in || !info->out)
1510                 status = usbnet_get_endpoints (dev, udev);
1511         else {
1512                 dev->in = usb_rcvbulkpipe (xdev, info->in);
1513                 dev->out = usb_sndbulkpipe (xdev, info->out);
1514                 if (!(info->flags & FLAG_NO_SETINT))
1515                         status = usb_set_interface (xdev,
1516                                 interface->desc.bInterfaceNumber,
1517                                 interface->desc.bAlternateSetting);
1518                 else
1519                         status = 0;
1520
1521         }
1522         if (status >= 0 && dev->status)
1523                 status = init_status (dev, udev);
1524         if (status < 0)
1525                 goto out3;
1526
1527         if (!dev->rx_urb_size)
1528                 dev->rx_urb_size = dev->hard_mtu;
1529         dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
1530
1531         if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1532                 SET_NETDEV_DEVTYPE(net, &wlan_type);
1533         if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1534                 SET_NETDEV_DEVTYPE(net, &wwan_type);
1535
1536         status = register_netdev (net);
1537         if (status)
1538                 goto out4;
1539         netif_info(dev, probe, dev->net,
1540                    "register '%s' at usb-%s-%s, %s, %pM\n",
1541                    udev->dev.driver->name,
1542                    xdev->bus->bus_name, xdev->devpath,
1543                    dev->driver_info->description,
1544                    net->dev_addr);
1545
1546         // ok, it's ready to go.
1547         usb_set_intfdata (udev, dev);
1548
1549         netif_device_attach (net);
1550
1551         if (dev->driver_info->flags & FLAG_LINK_INTR)
1552                 usbnet_link_change(dev, 0, 0);
1553
1554         return 0;
1555
1556 out4:
1557         usb_free_urb(dev->interrupt);
1558 out3:
1559         if (info->unbind)
1560                 info->unbind (dev, udev);
1561 out1:
1562         free_netdev(net);
1563 out:
1564         return status;
1565 }
1566 EXPORT_SYMBOL_GPL(usbnet_probe);
1567
1568 /*-------------------------------------------------------------------------*/
1569
1570 /*
1571  * suspend the whole driver as soon as the first interface is suspended
1572  * resume only when the last interface is resumed
1573  */
1574
1575 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1576 {
1577         struct usbnet           *dev = usb_get_intfdata(intf);
1578
1579         if (!dev->suspend_count++) {
1580                 spin_lock_irq(&dev->txq.lock);
1581                 /* don't autosuspend while transmitting */
1582                 if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1583                         dev->suspend_count--;
1584                         spin_unlock_irq(&dev->txq.lock);
1585                         return -EBUSY;
1586                 } else {
1587                         set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1588                         spin_unlock_irq(&dev->txq.lock);
1589                 }
1590                 /*
1591                  * accelerate emptying of the rx and queues, to avoid
1592                  * having everything error out.
1593                  */
1594                 netif_device_detach (dev->net);
1595                 usbnet_terminate_urbs(dev);
1596                 usb_kill_urb(dev->interrupt);
1597
1598                 /*
1599                  * reattach so runtime management can use and
1600                  * wake the device
1601                  */
1602                 netif_device_attach (dev->net);
1603         }
1604         return 0;
1605 }
1606 EXPORT_SYMBOL_GPL(usbnet_suspend);
1607
1608 int usbnet_resume (struct usb_interface *intf)
1609 {
1610         struct usbnet           *dev = usb_get_intfdata(intf);
1611         struct sk_buff          *skb;
1612         struct urb              *res;
1613         int                     retval;
1614
1615         if (!--dev->suspend_count) {
1616                 /* resume interrupt URBs */
1617                 if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
1618                         usb_submit_urb(dev->interrupt, GFP_NOIO);
1619
1620                 spin_lock_irq(&dev->txq.lock);
1621                 while ((res = usb_get_from_anchor(&dev->deferred))) {
1622
1623                         skb = (struct sk_buff *)res->context;
1624                         retval = usb_submit_urb(res, GFP_ATOMIC);
1625                         if (retval < 0) {
1626                                 dev_kfree_skb_any(skb);
1627                                 usb_free_urb(res);
1628                                 usb_autopm_put_interface_async(dev->intf);
1629                         } else {
1630                                 dev->net->trans_start = jiffies;
1631                                 __skb_queue_tail(&dev->txq, skb);
1632                         }
1633                 }
1634
1635                 smp_mb();
1636                 clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1637                 spin_unlock_irq(&dev->txq.lock);
1638
1639                 if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1640                         /* handle remote wakeup ASAP */
1641                         if (!dev->wait &&
1642                                 netif_device_present(dev->net) &&
1643                                 !timer_pending(&dev->delay) &&
1644                                 !test_bit(EVENT_RX_HALT, &dev->flags))
1645                                         rx_alloc_submit(dev, GFP_NOIO);
1646
1647                         if (!(dev->txq.qlen >= TX_QLEN(dev)))
1648                                 netif_tx_wake_all_queues(dev->net);
1649                         tasklet_schedule (&dev->bh);
1650                 }
1651         }
1652
1653         if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1654                 usb_autopm_get_interface_no_resume(intf);
1655
1656         return 0;
1657 }
1658 EXPORT_SYMBOL_GPL(usbnet_resume);
1659
1660 /*
1661  * Either a subdriver implements manage_power, then it is assumed to always
1662  * be ready to be suspended or it reports the readiness to be suspended
1663  * explicitly
1664  */
1665 void usbnet_device_suggests_idle(struct usbnet *dev)
1666 {
1667         if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1668                 dev->intf->needs_remote_wakeup = 1;
1669                 usb_autopm_put_interface_async(dev->intf);
1670         }
1671 }
1672 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1673
1674 /*
1675  * For devices that can do without special commands
1676  */
1677 int usbnet_manage_power(struct usbnet *dev, int on)
1678 {
1679         dev->intf->needs_remote_wakeup = on;
1680         return 0;
1681 }
1682 EXPORT_SYMBOL(usbnet_manage_power);
1683
1684 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1685 {
1686         /* update link after link is reseted */
1687         if (link && !need_reset)
1688                 netif_carrier_on(dev->net);
1689         else
1690                 netif_carrier_off(dev->net);
1691
1692         if (need_reset && link)
1693                 usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1694         else
1695                 usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1696 }
1697 EXPORT_SYMBOL(usbnet_link_change);
1698
1699 /*-------------------------------------------------------------------------*/
1700 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1701                              u16 value, u16 index, void *data, u16 size)
1702 {
1703         void *buf = NULL;
1704         int err = -ENOMEM;
1705
1706         netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
1707                    " value=0x%04x index=0x%04x size=%d\n",
1708                    cmd, reqtype, value, index, size);
1709
1710         if (data) {
1711                 buf = kmalloc(size, GFP_KERNEL);
1712                 if (!buf)
1713                         goto out;
1714         }
1715
1716         err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
1717                               cmd, reqtype, value, index, buf, size,
1718                               USB_CTRL_GET_TIMEOUT);
1719         if (err > 0 && err <= size)
1720                 memcpy(data, buf, err);
1721         kfree(buf);
1722 out:
1723         return err;
1724 }
1725
1726 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1727                               u16 value, u16 index, const void *data,
1728                               u16 size)
1729 {
1730         void *buf = NULL;
1731         int err = -ENOMEM;
1732
1733         netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1734                    " value=0x%04x index=0x%04x size=%d\n",
1735                    cmd, reqtype, value, index, size);
1736
1737         if (data) {
1738                 buf = kmemdup(data, size, GFP_KERNEL);
1739                 if (!buf)
1740                         goto out;
1741         }
1742
1743         err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
1744                               cmd, reqtype, value, index, buf, size,
1745                               USB_CTRL_SET_TIMEOUT);
1746         kfree(buf);
1747
1748 out:
1749         return err;
1750 }
1751
1752 /*
1753  * The function can't be called inside suspend/resume callback,
1754  * otherwise deadlock will be caused.
1755  */
1756 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1757                     u16 value, u16 index, void *data, u16 size)
1758 {
1759         int ret;
1760
1761         if (usb_autopm_get_interface(dev->intf) < 0)
1762                 return -ENODEV;
1763         ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1764                                 data, size);
1765         usb_autopm_put_interface(dev->intf);
1766         return ret;
1767 }
1768 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
1769
1770 /*
1771  * The function can't be called inside suspend/resume callback,
1772  * otherwise deadlock will be caused.
1773  */
1774 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1775                      u16 value, u16 index, const void *data, u16 size)
1776 {
1777         int ret;
1778
1779         if (usb_autopm_get_interface(dev->intf) < 0)
1780                 return -ENODEV;
1781         ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1782                                  data, size);
1783         usb_autopm_put_interface(dev->intf);
1784         return ret;
1785 }
1786 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
1787
1788 /*
1789  * The function can be called inside suspend/resume callback safely
1790  * and should only be called by suspend/resume callback generally.
1791  */
1792 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1793                           u16 value, u16 index, void *data, u16 size)
1794 {
1795         return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
1796                                  data, size);
1797 }
1798 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
1799
1800 /*
1801  * The function can be called inside suspend/resume callback safely
1802  * and should only be called by suspend/resume callback generally.
1803  */
1804 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
1805                           u16 value, u16 index, const void *data,
1806                           u16 size)
1807 {
1808         return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
1809                                   data, size);
1810 }
1811 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
1812
1813 static void usbnet_async_cmd_cb(struct urb *urb)
1814 {
1815         struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
1816         int status = urb->status;
1817
1818         if (status < 0)
1819                 dev_dbg(&urb->dev->dev, "%s failed with %d",
1820                         __func__, status);
1821
1822         kfree(req);
1823         usb_free_urb(urb);
1824 }
1825
1826 /*
1827  * The caller must make sure that device can't be put into suspend
1828  * state until the control URB completes.
1829  */
1830 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
1831                            u16 value, u16 index, const void *data, u16 size)
1832 {
1833         struct usb_ctrlrequest *req = NULL;
1834         struct urb *urb;
1835         int err = -ENOMEM;
1836         void *buf = NULL;
1837
1838         netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
1839                    " value=0x%04x index=0x%04x size=%d\n",
1840                    cmd, reqtype, value, index, size);
1841
1842         urb = usb_alloc_urb(0, GFP_ATOMIC);
1843         if (!urb) {
1844                 netdev_err(dev->net, "Error allocating URB in"
1845                            " %s!\n", __func__);
1846                 goto fail;
1847         }
1848
1849         if (data) {
1850                 buf = kmemdup(data, size, GFP_ATOMIC);
1851                 if (!buf) {
1852                         netdev_err(dev->net, "Error allocating buffer"
1853                                    " in %s!\n", __func__);
1854                         goto fail_free;
1855                 }
1856         }
1857
1858         req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
1859         if (!req)
1860                 goto fail_free_buf;
1861
1862         req->bRequestType = reqtype;
1863         req->bRequest = cmd;
1864         req->wValue = cpu_to_le16(value);
1865         req->wIndex = cpu_to_le16(index);
1866         req->wLength = cpu_to_le16(size);
1867
1868         usb_fill_control_urb(urb, dev->udev,
1869                              usb_sndctrlpipe(dev->udev, 0),
1870                              (void *)req, buf, size,
1871                              usbnet_async_cmd_cb, req);
1872         urb->transfer_flags |= URB_FREE_BUFFER;
1873
1874         err = usb_submit_urb(urb, GFP_ATOMIC);
1875         if (err < 0) {
1876                 netdev_err(dev->net, "Error submitting the control"
1877                            " message: status=%d\n", err);
1878                 goto fail_free;
1879         }
1880         return 0;
1881
1882 fail_free_buf:
1883         kfree(buf);
1884 fail_free:
1885         kfree(req);
1886         usb_free_urb(urb);
1887 fail:
1888         return err;
1889
1890 }
1891 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
1892 /*-------------------------------------------------------------------------*/
1893
1894 static int __init usbnet_init(void)
1895 {
1896         /* Compiler should optimize this out. */
1897         BUILD_BUG_ON(
1898                 FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
1899
1900         eth_random_addr(node_id);
1901         return 0;
1902 }
1903 module_init(usbnet_init);
1904
1905 static void __exit usbnet_exit(void)
1906 {
1907 }
1908 module_exit(usbnet_exit);
1909
1910 MODULE_AUTHOR("David Brownell");
1911 MODULE_DESCRIPTION("USB network driver framework");
1912 MODULE_LICENSE("GPL");