drivers/scsi/scsi_netlink.c

   1 /*
   2  *  scsi_netlink.c  - SCSI Transport Netlink Interface
   3  *
   4  *  Copyright (C) 2006   James Smart, Emulex Corporation
   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 #include <linux/time.h>
  22 #include <linux/jiffies.h>
  23 #include <linux/security.h>
  24 #include <linux/delay.h>
  25 #include <linux/slab.h>
  26 #include <linux/export.h>
  27 #include <net/sock.h>
  28 #include <net/netlink.h>
  29
  30 #include <scsi/scsi_netlink.h>
  31 #include "scsi_priv.h"
  32
  33 struct sock *scsi_nl_sock = NULL;
  34 EXPORT_SYMBOL_GPL(scsi_nl_sock);
  35
  36 static DEFINE_SPINLOCK(scsi_nl_lock);
  37 static struct list_head scsi_nl_drivers;
  38
  39 static u32      scsi_nl_state;
  40 #define STATE_EHANDLER_BSY              0x00000001
  41
  42 struct scsi_nl_transport {
  43         int (*msg_handler)(struct sk_buff *);
  44         void (*event_handler)(struct notifier_block *, unsigned long, void *);
  45         unsigned int refcnt;
  46         int flags;
  47 };
  48
  49 /* flags values (bit flags) */
  50 #define HANDLER_DELETING                0x1
  51
  52 static struct scsi_nl_transport transports[SCSI_NL_MAX_TRANSPORTS] =
  53         { {NULL, }, };
  54
  55
  56 struct scsi_nl_drvr {
  57         struct list_head next;
  58         int (*dmsg_handler)(struct Scsi_Host *shost, void *payload,
  59                                  u32 len, u32 pid);
  60         void (*devt_handler)(struct notifier_block *nb,
  61                                  unsigned long event, void *notify_ptr);
  62         struct scsi_host_template *hostt;
  63         u64 vendor_id;
  64         unsigned int refcnt;
  65         int flags;
  66 };
  67
  68
  69
  70 /**
  71  * scsi_nl_rcv_msg - Receive message handler.
  72  * @skb:                socket receive buffer
  73  *
  74  * Description: Extracts message from a receive buffer.
  75  *    Validates message header and calls appropriate transport message handler
  76  *
  77  *
  78  **/
  79 static void
  80 scsi_nl_rcv_msg(struct sk_buff *skb)
  81 {
  82         struct nlmsghdr *nlh;
  83         struct scsi_nl_hdr *hdr;
  84         unsigned long flags;
  85         u32 rlen;
  86         int err, tport;
  87
  88         while (skb->len >= NLMSG_SPACE(0)) {
  89                 err = 0;
  90
  91                 nlh = nlmsg_hdr(skb);
  92                 if ((nlh->nlmsg_len < (sizeof(*nlh) + sizeof(*hdr))) ||
  93                     (skb->len < nlh->nlmsg_len)) {
  94                         printk(KERN_WARNING "%s: discarding partial skb\n",
  95                                  __func__);
  96                         return;
  97                 }
  98
  99                 rlen = NLMSG_ALIGN(nlh->nlmsg_len);
 100                 if (rlen > skb->len)
 101                         rlen = skb->len;
 102
 103                 if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
 104                         err = -EBADMSG;
 105                         goto next_msg;
 106                 }
 107
 108                 hdr = NLMSG_DATA(nlh);
 109                 if ((hdr->version != SCSI_NL_VERSION) ||
 110                     (hdr->magic != SCSI_NL_MAGIC)) {
 111                         err = -EPROTOTYPE;
 112                         goto next_msg;
 113                 }
 114
 115                 if (!capable(CAP_SYS_ADMIN)) {
 116                         err = -EPERM;
 117                         goto next_msg;
 118                 }
 119
 120                 if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
 121                         printk(KERN_WARNING "%s: discarding partial message\n",
 122                                  __func__);
 123                         goto next_msg;
 124                 }
 125
 126                 /*
 127                  * Deliver message to the appropriate transport
 128                  */
 129                 spin_lock_irqsave(&scsi_nl_lock, flags);
 130
 131                 tport = hdr->transport;
 132                 if ((tport < SCSI_NL_MAX_TRANSPORTS) &&
 133                     !(transports[tport].flags & HANDLER_DELETING) &&
 134                     (transports[tport].msg_handler)) {
 135                         transports[tport].refcnt++;
 136                         spin_unlock_irqrestore(&scsi_nl_lock, flags);
 137                         err = transports[tport].msg_handler(skb);
 138                         spin_lock_irqsave(&scsi_nl_lock, flags);
 139                         transports[tport].refcnt--;
 140                 } else
 141                         err = -ENOENT;
 142
 143                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
 144
 145 next_msg:
 146                 if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
 147                         netlink_ack(skb, nlh, err);
 148
 149                 skb_pull(skb, rlen);
 150         }
 151 }
 152
 153
 154 /**
 155  * scsi_nl_rcv_event - Event handler for a netlink socket.
 156  * @this:               event notifier block
 157  * @event:              event type
 158  * @ptr:                event payload
 159  *
 160  **/
 161 static int
 162 scsi_nl_rcv_event(struct notifier_block *this, unsigned long event, void *ptr)
 163 {
 164         struct netlink_notify *n = ptr;
 165         struct scsi_nl_drvr *driver;
 166         unsigned long flags;
 167         int tport;
 168
 169         if (n->protocol != NETLINK_SCSITRANSPORT)
 170                 return NOTIFY_DONE;
 171
 172         spin_lock_irqsave(&scsi_nl_lock, flags);
 173         scsi_nl_state |= STATE_EHANDLER_BSY;
 174
 175         /*
 176          * Pass event on to any transports that may be listening
 177          */
 178         for (tport = 0; tport < SCSI_NL_MAX_TRANSPORTS; tport++) {
 179                 if (!(transports[tport].flags & HANDLER_DELETING) &&
 180                     (transports[tport].event_handler)) {
 181                         spin_unlock_irqrestore(&scsi_nl_lock, flags);
 182                         transports[tport].event_handler(this, event, ptr);
 183                         spin_lock_irqsave(&scsi_nl_lock, flags);
 184                 }
 185         }
 186
 187         /*
 188          * Pass event on to any drivers that may be listening
 189          */
 190         list_for_each_entry(driver, &scsi_nl_drivers, next) {
 191                 if (!(driver->flags & HANDLER_DELETING) &&
 192                     (driver->devt_handler)) {
 193                         spin_unlock_irqrestore(&scsi_nl_lock, flags);
 194                         driver->devt_handler(this, event, ptr);
 195                         spin_lock_irqsave(&scsi_nl_lock, flags);
 196                 }
 197         }
 198
 199         scsi_nl_state &= ~STATE_EHANDLER_BSY;
 200         spin_unlock_irqrestore(&scsi_nl_lock, flags);
 201
 202         return NOTIFY_DONE;
 203 }
 204
 205 static struct notifier_block scsi_netlink_notifier = {
 206         .notifier_call  = scsi_nl_rcv_event,
 207 };
 208
 209
 210 /*
 211  * GENERIC SCSI transport receive and event handlers
 212  */
 213
 214 /**
 215  * scsi_generic_msg_handler - receive message handler for GENERIC transport messages
 216  * @skb:                socket receive buffer
 217  **/
 218 static int
 219 scsi_generic_msg_handler(struct sk_buff *skb)
 220 {
 221         struct nlmsghdr *nlh = nlmsg_hdr(skb);
 222         struct scsi_nl_hdr *snlh = NLMSG_DATA(nlh);
 223         struct scsi_nl_drvr *driver;
 224         struct Scsi_Host *shost;
 225         unsigned long flags;
 226         int err = 0, match, pid;
 227
 228         pid = NETLINK_CREDS(skb)->pid;
 229
 230         switch (snlh->msgtype) {
 231         case SCSI_NL_SHOST_VENDOR:
 232                 {
 233                 struct scsi_nl_host_vendor_msg *msg = NLMSG_DATA(nlh);
 234
 235                 /* Locate the driver that corresponds to the message */
 236                 spin_lock_irqsave(&scsi_nl_lock, flags);
 237                 match = 0;
 238                 list_for_each_entry(driver, &scsi_nl_drivers, next) {
 239                         if (driver->vendor_id == msg->vendor_id) {
 240                                 match = 1;
 241                                 break;
 242                         }
 243                 }
 244
 245                 if ((!match) || (!driver->dmsg_handler)) {
 246                         spin_unlock_irqrestore(&scsi_nl_lock, flags);
 247                         err = -ESRCH;
 248                         goto rcv_exit;
 249                 }
 250
 251                 if (driver->flags & HANDLER_DELETING) {
 252                         spin_unlock_irqrestore(&scsi_nl_lock, flags);
 253                         err = -ESHUTDOWN;
 254                         goto rcv_exit;
 255                 }
 256
 257                 driver->refcnt++;
 258                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
 259
 260
 261                 /* if successful, scsi_host_lookup takes a shost reference */
 262                 shost = scsi_host_lookup(msg->host_no);
 263                 if (!shost) {
 264                         err = -ENODEV;
 265                         goto driver_exit;
 266                 }
 267
 268                 /* is this host owned by the vendor ? */
 269                 if (shost->hostt != driver->hostt) {
 270                         err = -EINVAL;
 271                         goto vendormsg_put;
 272                 }
 273
 274                 /* pass message on to the driver */
 275                 err = driver->dmsg_handler(shost, (void *)&msg[1],
 276                                          msg->vmsg_datalen, pid);
 277
 278 vendormsg_put:
 279                 /* release reference by scsi_host_lookup */
 280                 scsi_host_put(shost);
 281
 282 driver_exit:
 283                 /* release our own reference on the registration object */
 284                 spin_lock_irqsave(&scsi_nl_lock, flags);
 285                 driver->refcnt--;
 286                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
 287                 break;
 288                 }
 289
 290         default:
 291                 err = -EBADR;
 292                 break;
 293         }
 294
 295 rcv_exit:
 296         if (err)
 297                 printk(KERN_WARNING "%s: Msgtype %d failed - err %d\n",
 298                          __func__, snlh->msgtype, err);
 299         return err;
 300 }
 301
 302
 303 /**
 304  * scsi_nl_add_transport -
 305  *    Registers message and event handlers for a transport. Enables
 306  *    receipt of netlink messages and events to a transport.
 307  *
 308  * @tport:              transport registering handlers
 309  * @msg_handler:        receive message handler callback
 310  * @event_handler:      receive event handler callback
 311  **/
 312 int
 313 scsi_nl_add_transport(u8 tport,
 314         int (*msg_handler)(struct sk_buff *),
 315         void (*event_handler)(struct notifier_block *, unsigned long, void *))
 316 {
 317         unsigned long flags;
 318         int err = 0;
 319
 320         if (tport >= SCSI_NL_MAX_TRANSPORTS)
 321                 return -EINVAL;
 322
 323         spin_lock_irqsave(&scsi_nl_lock, flags);
 324
 325         if (scsi_nl_state & STATE_EHANDLER_BSY) {
 326                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
 327                 msleep(1);
 328                 spin_lock_irqsave(&scsi_nl_lock, flags);
 329         }
 330
 331         if (transports[tport].msg_handler || transports[tport].event_handler) {
 332                 err = -EALREADY;
 333                 goto register_out;
 334         }
 335
 336         transports[tport].msg_handler = msg_handler;
 337         transports[tport].event_handler = event_handler;
 338         transports[tport].flags = 0;
 339         transports[tport].refcnt = 0;
 340
 341 register_out:
 342         spin_unlock_irqrestore(&scsi_nl_lock, flags);
 343
 344         return err;
 345 }
 346 EXPORT_SYMBOL_GPL(scsi_nl_add_transport);
 347
 348
 349 /**
 350  * scsi_nl_remove_transport -
 351  *    Disable transport receiption of messages and events
 352  *
 353  * @tport:              transport deregistering handlers
 354  *
 355  **/
 356 void
 357 scsi_nl_remove_transport(u8 tport)
 358 {
 359         unsigned long flags;
 360
 361         spin_lock_irqsave(&scsi_nl_lock, flags);
 362         if (scsi_nl_state & STATE_EHANDLER_BSY) {
 363                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
 364                 msleep(1);
 365                 spin_lock_irqsave(&scsi_nl_lock, flags);
 366         }
 367
 368         if (tport < SCSI_NL_MAX_TRANSPORTS) {
 369                 transports[tport].flags |= HANDLER_DELETING;
 370
 371                 while (transports[tport].refcnt != 0) {
 372                         spin_unlock_irqrestore(&scsi_nl_lock, flags);
 373                         schedule_timeout_uninterruptible(HZ/4);
 374                         spin_lock_irqsave(&scsi_nl_lock, flags);
 375                 }
 376                 transports[tport].msg_handler = NULL;
 377                 transports[tport].event_handler = NULL;
 378                 transports[tport].flags = 0;
 379         }
 380
 381         spin_unlock_irqrestore(&scsi_nl_lock, flags);
 382
 383         return;
 384 }
 385 EXPORT_SYMBOL_GPL(scsi_nl_remove_transport);
 386
 387
 388 /**
 389  * scsi_nl_add_driver -
 390  *    A driver is registering its interfaces for SCSI netlink messages
 391  *
 392  * @vendor_id:          A unique identification value for the driver.
 393  * @hostt:              address of the driver's host template. Used
 394  *                      to verify an shost is bound to the driver
 395  * @nlmsg_handler:      receive message handler callback
 396  * @nlevt_handler:      receive event handler callback
 397  *
 398  * Returns:
 399  *   0 on Success
 400  *   error result otherwise
 401  **/
 402 int
 403 scsi_nl_add_driver(u64 vendor_id, struct scsi_host_template *hostt,
 404         int (*nlmsg_handler)(struct Scsi_Host *shost, void *payload,
 405                                  u32 len, u32 pid),
 406         void (*nlevt_handler)(struct notifier_block *nb,
 407                                  unsigned long event, void *notify_ptr))
 408 {
 409         struct scsi_nl_drvr *driver;
 410         unsigned long flags;
 411
 412         driver = kzalloc(sizeof(*driver), GFP_KERNEL);
 413         if (unlikely(!driver)) {
 414                 printk(KERN_ERR "%s: allocation failure\n", __func__);
 415                 return -ENOMEM;
 416         }
 417
 418         driver->dmsg_handler = nlmsg_handler;
 419         driver->devt_handler = nlevt_handler;
 420         driver->hostt = hostt;
 421         driver->vendor_id = vendor_id;
 422
 423         spin_lock_irqsave(&scsi_nl_lock, flags);
 424         if (scsi_nl_state & STATE_EHANDLER_BSY) {
 425                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
 426                 msleep(1);
 427                 spin_lock_irqsave(&scsi_nl_lock, flags);
 428         }
 429         list_add_tail(&driver->next, &scsi_nl_drivers);
 430         spin_unlock_irqrestore(&scsi_nl_lock, flags);
 431
 432         return 0;
 433 }
 434 EXPORT_SYMBOL_GPL(scsi_nl_add_driver);
 435
 436
 437 /**
 438  * scsi_nl_remove_driver -
 439  *    An driver is unregistering with the SCSI netlink messages
 440  *
 441  * @vendor_id:          The unique identification value for the driver.
 442  **/
 443 void
 444 scsi_nl_remove_driver(u64 vendor_id)
 445 {
 446         struct scsi_nl_drvr *driver;
 447         unsigned long flags;
 448
 449         spin_lock_irqsave(&scsi_nl_lock, flags);
 450         if (scsi_nl_state & STATE_EHANDLER_BSY) {
 451                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
 452                 msleep(1);
 453                 spin_lock_irqsave(&scsi_nl_lock, flags);
 454         }
 455
 456         list_for_each_entry(driver, &scsi_nl_drivers, next) {
 457                 if (driver->vendor_id == vendor_id) {
 458                         driver->flags |= HANDLER_DELETING;
 459                         while (driver->refcnt != 0) {
 460                                 spin_unlock_irqrestore(&scsi_nl_lock, flags);
 461                                 schedule_timeout_uninterruptible(HZ/4);
 462                                 spin_lock_irqsave(&scsi_nl_lock, flags);
 463                         }
 464                         list_del(&driver->next);
 465                         kfree(driver);
 466                         spin_unlock_irqrestore(&scsi_nl_lock, flags);
 467                         return;
 468                 }
 469         }
 470
 471         spin_unlock_irqrestore(&scsi_nl_lock, flags);
 472
 473         printk(KERN_ERR "%s: removal of driver failed - vendor_id 0x%llx\n",
 474                __func__, (unsigned long long)vendor_id);
 475         return;
 476 }
 477 EXPORT_SYMBOL_GPL(scsi_nl_remove_driver);
 478
 479
 480 /**
 481  * scsi_netlink_init - Called by SCSI subsystem to initialize
 482  *      the SCSI transport netlink interface
 483  *
 484  **/
 485 void
 486 scsi_netlink_init(void)
 487 {
 488         int error;
 489
 490         INIT_LIST_HEAD(&scsi_nl_drivers);
 491
 492         error = netlink_register_notifier(&scsi_netlink_notifier);
 493         if (error) {
 494                 printk(KERN_ERR "%s: register of event handler failed - %d\n",
 495                                 __func__, error);
 496                 return;
 497         }
 498
 499         scsi_nl_sock = netlink_kernel_create(&init_net, NETLINK_SCSITRANSPORT,
 500                                 SCSI_NL_GRP_CNT, scsi_nl_rcv_msg, NULL,
 501                                 THIS_MODULE);
 502         if (!scsi_nl_sock) {
 503                 printk(KERN_ERR "%s: register of receive handler failed\n",
 504                                 __func__);
 505                 netlink_unregister_notifier(&scsi_netlink_notifier);
 506                 return;
 507         }
 508
 509         /* Register the entry points for the generic SCSI transport */
 510         error = scsi_nl_add_transport(SCSI_NL_TRANSPORT,
 511                                 scsi_generic_msg_handler, NULL);
 512         if (error)
 513                 printk(KERN_ERR "%s: register of GENERIC transport handler"
 514                                 "  failed - %d\n", __func__, error);
 515         return;
 516 }
 517
 518
 519 /**
 520  * scsi_netlink_exit - Called by SCSI subsystem to disable the SCSI transport netlink interface
 521  *
 522  **/
 523 void
 524 scsi_netlink_exit(void)
 525 {
 526         scsi_nl_remove_transport(SCSI_NL_TRANSPORT);
 527
 528         if (scsi_nl_sock) {
 529                 netlink_kernel_release(scsi_nl_sock);
 530                 netlink_unregister_notifier(&scsi_netlink_notifier);
 531         }
 532
 533         return;
 534 }
 535
 536
 537 /*
 538  * Exported Interfaces
 539  */
 540
 541 /**
 542  * scsi_nl_send_transport_msg -
 543  *    Generic function to send a single message from a SCSI transport to
 544  *    a single process
 545  *
 546  * @pid:                receiving pid
 547  * @hdr:                message payload
 548  *
 549  **/
 550 void
 551 scsi_nl_send_transport_msg(u32 pid, struct scsi_nl_hdr *hdr)
 552 {
 553         struct sk_buff *skb;
 554         struct nlmsghdr *nlh;
 555         const char *fn;
 556         char *datab;
 557         u32 len, skblen;
 558         int err;
 559
 560         if (!scsi_nl_sock) {
 561                 err = -ENOENT;
 562                 fn = "netlink socket";
 563                 goto msg_fail;
 564         }
 565
 566         len = NLMSG_SPACE(hdr->msglen);
 567         skblen = NLMSG_SPACE(len);
 568
 569         skb = alloc_skb(skblen, GFP_KERNEL);
 570         if (!skb) {
 571                 err = -ENOBUFS;
 572                 fn = "alloc_skb";
 573                 goto msg_fail;
 574         }
 575
 576         nlh = nlmsg_put(skb, pid, 0, SCSI_TRANSPORT_MSG, len - sizeof(*nlh), 0);
 577         if (!nlh) {
 578                 err = -ENOBUFS;
 579                 fn = "nlmsg_put";
 580                 goto msg_fail_skb;
 581         }
 582         datab = NLMSG_DATA(nlh);
 583         memcpy(datab, hdr, hdr->msglen);
 584
 585         err = nlmsg_unicast(scsi_nl_sock, skb, pid);
 586         if (err < 0) {
 587                 fn = "nlmsg_unicast";
 588                 /* nlmsg_unicast already kfree_skb'd */
 589                 goto msg_fail;
 590         }
 591
 592         return;
 593
 594 msg_fail_skb:
 595         kfree_skb(skb);
 596 msg_fail:
 597         printk(KERN_WARNING
 598                 "%s: Dropped Message : pid %d Transport %d, msgtype x%x, "
 599                 "msglen %d: %s : err %d\n",
 600                 __func__, pid, hdr->transport, hdr->msgtype, hdr->msglen,
 601                 fn, err);
 602         return;
 603 }
 604 EXPORT_SYMBOL_GPL(scsi_nl_send_transport_msg);
 605
 606
 607 /**
 608  * scsi_nl_send_vendor_msg - called to send a shost vendor unique message
 609  *                      to a specific process id.
 610  *
 611  * @pid:                process id of the receiver
 612  * @host_no:            host # sending the message
 613  * @vendor_id:          unique identifier for the driver's vendor
 614  * @data_len:           amount, in bytes, of vendor unique payload data
 615  * @data_buf:           pointer to vendor unique data buffer
 616  *
 617  * Returns:
 618  *   0 on successful return
 619  *   otherwise, failing error code
 620  *
 621  * Notes:
 622  *      This routine assumes no locks are held on entry.
 623  */
 624 int
 625 scsi_nl_send_vendor_msg(u32 pid, unsigned short host_no, u64 vendor_id,
 626                          char *data_buf, u32 data_len)
 627 {
 628         struct sk_buff *skb;
 629         struct nlmsghdr *nlh;
 630         struct scsi_nl_host_vendor_msg *msg;
 631         u32 len, skblen;
 632         int err;
 633
 634         if (!scsi_nl_sock) {
 635                 err = -ENOENT;
 636                 goto send_vendor_fail;
 637         }
 638
 639         len = SCSI_NL_MSGALIGN(sizeof(*msg) + data_len);
 640         skblen = NLMSG_SPACE(len);
 641
 642         skb = alloc_skb(skblen, GFP_KERNEL);
 643         if (!skb) {
 644                 err = -ENOBUFS;
 645                 goto send_vendor_fail;
 646         }
 647
 648         nlh = nlmsg_put(skb, 0, 0, SCSI_TRANSPORT_MSG,
 649                                 skblen - sizeof(*nlh), 0);
 650         if (!nlh) {
 651                 err = -ENOBUFS;
 652                 goto send_vendor_fail_skb;
 653         }
 654         msg = NLMSG_DATA(nlh);
 655
 656         INIT_SCSI_NL_HDR(&msg->snlh, SCSI_NL_TRANSPORT,
 657                                 SCSI_NL_SHOST_VENDOR, len);
 658         msg->vendor_id = vendor_id;
 659         msg->host_no = host_no;
 660         msg->vmsg_datalen = data_len;   /* bytes */
 661         memcpy(&msg[1], data_buf, data_len);
 662
 663         err = nlmsg_unicast(scsi_nl_sock, skb, pid);
 664         if (err)
 665                 /* nlmsg_multicast already kfree_skb'd */
 666                 goto send_vendor_fail;
 667
 668         return 0;
 669
 670 send_vendor_fail_skb:
 671         kfree_skb(skb);
 672 send_vendor_fail:
 673         printk(KERN_WARNING
 674                 "%s: Dropped SCSI Msg : host %d vendor_unique - err %d\n",
 675                 __func__, host_no, err);
 676         return err;
 677 }
 678 EXPORT_SYMBOL(scsi_nl_send_vendor_msg);
 679
 680