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