sys/cam/scsi/scsi_target.c

   1 /*-
   2  * Generic SCSI Target Kernel Mode Driver
   3  *
   4  * Copyright (c) 2002 Nate Lawson.
   5  * Copyright (c) 1998, 1999, 2001, 2002 Justin T. Gibbs.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions, and the following disclaimer,
  13  *    without modification, immediately at the beginning of the file.
  14  * 2. The name of the author may not be used to endorse or promote products
  15  *    derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  21  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include <sys/cdefs.h>
  31 __FBSDID("$FreeBSD$");
  32
  33
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/kernel.h>
  37 #include <sys/conf.h>
  38 #include <sys/malloc.h>
  39 #include <sys/poll.h>
  40 #include <sys/vnode.h>
  41 #include <sys/lock.h>
  42 #include <sys/mutex.h>
  43 #include <sys/devicestat.h>
  44 #include <sys/proc.h>
  45
  46 #include <cam/cam.h>
  47 #include <cam/cam_ccb.h>
  48 #include <cam/cam_periph.h>
  49 #include <cam/cam_xpt_periph.h>
  50 #include <cam/cam_sim.h>
  51 #include <cam/scsi/scsi_targetio.h>
  52
  53 /* Transaction information attached to each CCB sent by the user */
  54 struct targ_cmd_descr {
  55         struct cam_periph_map_info  mapinfo;
  56         TAILQ_ENTRY(targ_cmd_descr) tqe;
  57         union ccb *user_ccb;
  58         int        priority;
  59         int        func_code;
  60 };
  61
  62 /* Offset into the private CCB area for storing our descriptor */
  63 #define targ_descr      periph_priv.entries[1].ptr
  64
  65 TAILQ_HEAD(descr_queue, targ_cmd_descr);
  66
  67 typedef enum {
  68         TARG_STATE_RESV         = 0x00, /* Invalid state */
  69         TARG_STATE_OPENED       = 0x01, /* Device opened, softc initialized */
  70         TARG_STATE_LUN_ENABLED  = 0x02  /* Device enabled for a path */
  71 } targ_state;
  72
  73 /* Per-instance device software context */
  74 struct targ_softc {
  75         /* CCBs (CTIOs, ATIOs, INOTs) pending on the controller */
  76         struct ccb_queue         pending_ccb_queue;
  77
  78         /* Command descriptors awaiting CTIO resources from the XPT */
  79         struct descr_queue       work_queue;
  80
  81         /* Command descriptors that have been aborted back to the user. */
  82         struct descr_queue       abort_queue;
  83
  84         /*
  85          * Queue of CCBs that have been copied out to userland, but our
  86          * userland daemon has not yet seen.
  87          */
  88         struct ccb_queue         user_ccb_queue;
  89
  90         struct cam_periph       *periph;
  91         struct cam_path         *path;
  92         targ_state               state;
  93         struct selinfo           read_select;
  94         struct devstat           device_stats;
  95 };
  96
  97 static d_open_t         targopen;
  98 static d_close_t        targclose;
  99 static d_read_t         targread;
 100 static d_write_t        targwrite;
 101 static d_ioctl_t        targioctl;
 102 static d_poll_t         targpoll;
 103 static d_kqfilter_t     targkqfilter;
 104 static void             targreadfiltdetach(struct knote *kn);
 105 static int              targreadfilt(struct knote *kn, long hint);
 106 static struct filterops targread_filtops =
 107         { 1, NULL, targreadfiltdetach, targreadfilt };
 108
 109 static struct cdevsw targ_cdevsw = {
 110         .d_version =    D_VERSION,
 111         .d_flags =      D_NEEDGIANT,
 112         .d_open =       targopen,
 113         .d_close =      targclose,
 114         .d_read =       targread,
 115         .d_write =      targwrite,
 116         .d_ioctl =      targioctl,
 117         .d_poll =       targpoll,
 118         .d_name =       "targ",
 119         .d_kqfilter =   targkqfilter
 120 };
 121
 122 static cam_status       targendislun(struct cam_path *path, int enable,
 123                                      int grp6_len, int grp7_len);
 124 static cam_status       targenable(struct targ_softc *softc,
 125                                    struct cam_path *path,
 126                                    int grp6_len, int grp7_len);
 127 static cam_status       targdisable(struct targ_softc *softc);
 128 static periph_ctor_t    targctor;
 129 static periph_dtor_t    targdtor;
 130 static periph_start_t   targstart;
 131 static int              targusermerge(struct targ_softc *softc,
 132                                       struct targ_cmd_descr *descr,
 133                                       union ccb *ccb);
 134 static int              targsendccb(struct targ_softc *softc, union ccb *ccb,
 135                                     struct targ_cmd_descr *descr);
 136 static void             targdone(struct cam_periph *periph,
 137                                  union  ccb *done_ccb);
 138 static int              targreturnccb(struct targ_softc *softc,
 139                                       union  ccb *ccb);
 140 static union ccb *      targgetccb(struct targ_softc *softc, xpt_opcode type,
 141                                    int priority);
 142 static void             targfreeccb(struct targ_softc *softc, union ccb *ccb);
 143 static struct targ_cmd_descr *
 144                         targgetdescr(struct targ_softc *softc);
 145 static periph_init_t    targinit;
 146 static void             targclone(void *arg, struct ucred *cred, char *name,
 147                                   int namelen, struct cdev **dev);
 148 static void             targasync(void *callback_arg, u_int32_t code,
 149                                   struct cam_path *path, void *arg);
 150 static void             abort_all_pending(struct targ_softc *softc);
 151 static void             notify_user(struct targ_softc *softc);
 152 static int              targcamstatus(cam_status status);
 153 static size_t           targccblen(xpt_opcode func_code);
 154
 155 static struct periph_driver targdriver =
 156 {
 157         targinit, "targ",
 158         TAILQ_HEAD_INITIALIZER(targdriver.units), /* generation */ 0
 159 };
 160 PERIPHDRIVER_DECLARE(targ, targdriver);
 161
 162 static MALLOC_DEFINE(M_TARG, "TARG", "TARG data");
 163
 164 /*
 165  * Create softc and initialize it. Only one proc can open each targ device.
 166  * There is no locking here because a periph doesn't get created until an
 167  * ioctl is issued to do so, and that can't happen until this method returns.
 168  */
 169 static int
 170 targopen(struct cdev *dev, int flags, int fmt, struct thread *td)
 171 {
 172         struct targ_softc *softc;
 173
 174         if (dev->si_drv1 != 0) {
 175                 return (EBUSY);
 176         }
 177
 178         /* Mark device busy before any potentially blocking operations */
 179         dev->si_drv1 = (void *)~0;
 180
 181         /* Create the targ device, allocate its softc, initialize it */
 182         if ((dev->si_flags & SI_NAMED) == 0) {
 183                 make_dev(&targ_cdevsw, dev2unit(dev), UID_ROOT, GID_WHEEL, 0600,
 184                          "targ%d", dev2unit(dev));
 185         }
 186         softc = malloc(sizeof(*softc), M_TARG,
 187                M_WAITOK | M_ZERO);
 188         dev->si_drv1 = softc;
 189         softc->state = TARG_STATE_OPENED;
 190         softc->periph = NULL;
 191         softc->path = NULL;
 192
 193         TAILQ_INIT(&softc->pending_ccb_queue);
 194         TAILQ_INIT(&softc->work_queue);
 195         TAILQ_INIT(&softc->abort_queue);
 196         TAILQ_INIT(&softc->user_ccb_queue);
 197         knlist_init_mtx(&softc->read_select.si_note, NULL);
 198
 199         return (0);
 200 }
 201
 202 /* Disable LUN if enabled and teardown softc */
 203 static int
 204 targclose(struct cdev *dev, int flag, int fmt, struct thread *td)
 205 {
 206         struct targ_softc     *softc;
 207         struct cam_periph     *periph;
 208         int    error;
 209
 210         softc = (struct targ_softc *)dev->si_drv1;
 211         if ((softc->periph == NULL) ||
 212             (softc->state & TARG_STATE_LUN_ENABLED) == 0) {
 213                 destroy_dev(dev);
 214                 free(softc, M_TARG);
 215                 return (0);
 216         }
 217
 218         /*
 219          * Acquire a hold on the periph so that it doesn't go away before
 220          * we are ready at the end of the function.
 221          */
 222         periph = softc->periph;
 223         cam_periph_acquire(periph);
 224         cam_periph_lock(periph);
 225         error = targdisable(softc);
 226         if (error == CAM_REQ_CMP) {
 227                 dev->si_drv1 = 0;
 228                 if (softc->periph != NULL) {
 229                         cam_periph_invalidate(softc->periph);
 230                         softc->periph = NULL;
 231                 }
 232                 destroy_dev(dev);
 233                 free(softc, M_TARG);
 234         }
 235         cam_periph_unlock(periph);
 236         cam_periph_release(periph);
 237
 238         return (error);
 239 }
 240
 241 /* Enable/disable LUNs, set debugging level */
 242 static int
 243 targioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
 244 {
 245         struct targ_softc *softc;
 246         cam_status         status;
 247
 248         softc = (struct targ_softc *)dev->si_drv1;
 249
 250         switch (cmd) {
 251         case TARGIOCENABLE:
 252         {
 253                 struct ioc_enable_lun   *new_lun;
 254                 struct cam_path         *path;
 255                 struct cam_sim          *sim;
 256
 257                 new_lun = (struct ioc_enable_lun *)addr;
 258                 status = xpt_create_path_unlocked(&path, /*periph*/NULL,
 259                                                   new_lun->path_id,
 260                                                   new_lun->target_id,
 261                                                   new_lun->lun_id);
 262                 if (status != CAM_REQ_CMP) {
 263                         printf("Couldn't create path, status %#x\n", status);
 264                         break;
 265                 }
 266                 sim = xpt_path_sim(path);
 267                 mtx_lock(sim->mtx);
 268                 status = targenable(softc, path, new_lun->grp6_len,
 269                                     new_lun->grp7_len);
 270                 xpt_free_path(path);
 271                 mtx_unlock(sim->mtx);
 272                 break;
 273         }
 274         case TARGIOCDISABLE:
 275                 if (softc->periph == NULL) {
 276                         status = CAM_DEV_NOT_THERE;
 277                         break;
 278                 }
 279                 cam_periph_lock(softc->periph);
 280                 status = targdisable(softc);
 281                 cam_periph_unlock(softc->periph);
 282                 break;
 283         case TARGIOCDEBUG:
 284         {
 285 #ifdef  CAMDEBUG
 286                 struct ccb_debug cdbg;
 287
 288                 /* If no periph available, disallow debugging changes */
 289                 if ((softc->state & TARG_STATE_LUN_ENABLED) == 0) {
 290                         status = CAM_DEV_NOT_THERE;
 291                         break;
 292                 }
 293                 bzero(&cdbg, sizeof cdbg);
 294                 if (*((int *)addr) != 0)
 295                         cdbg.flags = CAM_DEBUG_PERIPH;
 296                 else
 297                         cdbg.flags = CAM_DEBUG_NONE;
 298                 cam_periph_lock(softc->periph);
 299                 xpt_setup_ccb(&cdbg.ccb_h, softc->path, CAM_PRIORITY_NORMAL);
 300                 cdbg.ccb_h.func_code = XPT_DEBUG;
 301                 cdbg.ccb_h.cbfcnp = targdone;
 302
 303                 xpt_action((union ccb *)&cdbg);
 304                 cam_periph_unlock(softc->periph);
 305                 status = cdbg.ccb_h.status & CAM_STATUS_MASK;
 306 #else
 307                 status = CAM_FUNC_NOTAVAIL;
 308 #endif
 309                 break;
 310         }
 311         default:
 312                 status = CAM_PROVIDE_FAIL;
 313                 break;
 314         }
 315
 316         return (targcamstatus(status));
 317 }
 318
 319 /* Writes are always ready, reads wait for user_ccb_queue or abort_queue */
 320 static int
 321 targpoll(struct cdev *dev, int poll_events, struct thread *td)
 322 {
 323         struct targ_softc *softc;
 324         int     revents;
 325
 326         softc = (struct targ_softc *)dev->si_drv1;
 327
 328         /* Poll for write() is always ok. */
 329         revents = poll_events & (POLLOUT | POLLWRNORM);
 330         if ((poll_events & (POLLIN | POLLRDNORM)) != 0) {
 331                 /* Poll for read() depends on user and abort queues. */
 332                 cam_periph_lock(softc->periph);
 333                 if (!TAILQ_EMPTY(&softc->user_ccb_queue) ||
 334                     !TAILQ_EMPTY(&softc->abort_queue)) {
 335                         revents |= poll_events & (POLLIN | POLLRDNORM);
 336                 }
 337                 cam_periph_unlock(softc->periph);
 338                 /* Only sleep if the user didn't poll for write. */
 339                 if (revents == 0)
 340                         selrecord(td, &softc->read_select);
 341         }
 342
 343         return (revents);
 344 }
 345
 346 static int
 347 targkqfilter(struct cdev *dev, struct knote *kn)
 348 {
 349         struct  targ_softc *softc;
 350
 351         softc = (struct targ_softc *)dev->si_drv1;
 352         kn->kn_hook = (caddr_t)softc;
 353         kn->kn_fop = &targread_filtops;
 354         knlist_add(&softc->read_select.si_note, kn, 0);
 355         return (0);
 356 }
 357
 358 static void
 359 targreadfiltdetach(struct knote *kn)
 360 {
 361         struct  targ_softc *softc;
 362
 363         softc = (struct targ_softc *)kn->kn_hook;
 364         knlist_remove(&softc->read_select.si_note, kn, 0);
 365 }
 366
 367 /* Notify the user's kqueue when the user queue or abort queue gets a CCB */
 368 static int
 369 targreadfilt(struct knote *kn, long hint)
 370 {
 371         struct targ_softc *softc;
 372         int     retval;
 373
 374         softc = (struct targ_softc *)kn->kn_hook;
 375         cam_periph_lock(softc->periph);
 376         retval = !TAILQ_EMPTY(&softc->user_ccb_queue) ||
 377                  !TAILQ_EMPTY(&softc->abort_queue);
 378         cam_periph_unlock(softc->periph);
 379         return (retval);
 380 }
 381
 382 /* Send the HBA the enable/disable message */
 383 static cam_status
 384 targendislun(struct cam_path *path, int enable, int grp6_len, int grp7_len)
 385 {
 386         struct ccb_en_lun en_ccb;
 387         cam_status        status;
 388
 389         /* Tell the lun to begin answering selects */
 390         xpt_setup_ccb(&en_ccb.ccb_h, path, CAM_PRIORITY_NORMAL);
 391         en_ccb.ccb_h.func_code = XPT_EN_LUN;
 392         /* Don't need support for any vendor specific commands */
 393         en_ccb.grp6_len = grp6_len;
 394         en_ccb.grp7_len = grp7_len;
 395         en_ccb.enable = enable ? 1 : 0;
 396         xpt_action((union ccb *)&en_ccb);
 397         status = en_ccb.ccb_h.status & CAM_STATUS_MASK;
 398         if (status != CAM_REQ_CMP) {
 399                 xpt_print(path, "%sable lun CCB rejected, status %#x\n",
 400                     enable ? "en" : "dis", status);
 401         }
 402         return (status);
 403 }
 404
 405 /* Enable target mode on a LUN, given its path */
 406 static cam_status
 407 targenable(struct targ_softc *softc, struct cam_path *path, int grp6_len,
 408            int grp7_len)
 409 {
 410         struct cam_periph *periph;
 411         struct ccb_pathinq cpi;
 412         cam_status         status;
 413
 414         if ((softc->state & TARG_STATE_LUN_ENABLED) != 0)
 415                 return (CAM_LUN_ALRDY_ENA);
 416
 417         /* Make sure SIM supports target mode */
 418         xpt_setup_ccb(&cpi.ccb_h, path, CAM_PRIORITY_NORMAL);
 419         cpi.ccb_h.func_code = XPT_PATH_INQ;
 420         xpt_action((union ccb *)&cpi);
 421         status = cpi.ccb_h.status & CAM_STATUS_MASK;
 422         if (status != CAM_REQ_CMP) {
 423                 printf("pathinq failed, status %#x\n", status);
 424                 goto enable_fail;
 425         }
 426         if ((cpi.target_sprt & PIT_PROCESSOR) == 0) {
 427                 printf("controller does not support target mode\n");
 428                 status = CAM_FUNC_NOTAVAIL;
 429                 goto enable_fail;
 430         }
 431
 432         /* Destroy any periph on our path if it is disabled */
 433         periph = cam_periph_find(path, "targ");
 434         if (periph != NULL) {
 435                 struct targ_softc *del_softc;
 436
 437                 del_softc = (struct targ_softc *)periph->softc;
 438                 if ((del_softc->state & TARG_STATE_LUN_ENABLED) == 0) {
 439                         cam_periph_invalidate(del_softc->periph);
 440                         del_softc->periph = NULL;
 441                 } else {
 442                         printf("Requested path still in use by targ%d\n",
 443                                periph->unit_number);
 444                         status = CAM_LUN_ALRDY_ENA;
 445                         goto enable_fail;
 446                 }
 447         }
 448
 449         /* Create a periph instance attached to this path */
 450         status = cam_periph_alloc(targctor, NULL, targdtor, targstart,
 451                         "targ", CAM_PERIPH_BIO, path, targasync, 0, softc);
 452         if (status != CAM_REQ_CMP) {
 453                 printf("cam_periph_alloc failed, status %#x\n", status);
 454                 goto enable_fail;
 455         }
 456
 457         /* Ensure that the periph now exists. */
 458         if (cam_periph_find(path, "targ") == NULL) {
 459                 panic("targenable: succeeded but no periph?");
 460                 /* NOTREACHED */
 461         }
 462
 463         /* Send the enable lun message */
 464         status = targendislun(path, /*enable*/1, grp6_len, grp7_len);
 465         if (status != CAM_REQ_CMP) {
 466                 printf("enable lun failed, status %#x\n", status);
 467                 goto enable_fail;
 468         }
 469         softc->state |= TARG_STATE_LUN_ENABLED;
 470
 471 enable_fail:
 472         return (status);
 473 }
 474
 475 /* Disable this softc's target instance if enabled */
 476 static cam_status
 477 targdisable(struct targ_softc *softc)
 478 {
 479         cam_status status;
 480
 481         if ((softc->state & TARG_STATE_LUN_ENABLED) == 0)
 482                 return (CAM_REQ_CMP);
 483
 484         CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("targdisable\n"));
 485
 486         /* Abort any ccbs pending on the controller */
 487         abort_all_pending(softc);
 488
 489         /* Disable this lun */
 490         status = targendislun(softc->path, /*enable*/0,
 491                               /*grp6_len*/0, /*grp7_len*/0);
 492         if (status == CAM_REQ_CMP)
 493                 softc->state &= ~TARG_STATE_LUN_ENABLED;
 494         else
 495                 printf("Disable lun failed, status %#x\n", status);
 496
 497         return (status);
 498 }
 499
 500 /* Initialize a periph (called from cam_periph_alloc) */
 501 static cam_status
 502 targctor(struct cam_periph *periph, void *arg)
 503 {
 504         struct targ_softc *softc;
 505
 506         /* Store pointer to softc for periph-driven routines */
 507         softc = (struct targ_softc *)arg;
 508         periph->softc = softc;
 509         softc->periph = periph;
 510         softc->path = periph->path;
 511         return (CAM_REQ_CMP);
 512 }
 513
 514 static void
 515 targdtor(struct cam_periph *periph)
 516 {
 517         struct targ_softc     *softc;
 518         struct ccb_hdr        *ccb_h;
 519         struct targ_cmd_descr *descr;
 520
 521         softc = (struct targ_softc *)periph->softc;
 522
 523         /*
 524          * targdisable() aborts CCBs back to the user and leaves them
 525          * on user_ccb_queue and abort_queue in case the user is still
 526          * interested in them.  We free them now.
 527          */
 528         while ((ccb_h = TAILQ_FIRST(&softc->user_ccb_queue)) != NULL) {
 529                 TAILQ_REMOVE(&softc->user_ccb_queue, ccb_h, periph_links.tqe);
 530                 targfreeccb(softc, (union ccb *)ccb_h);
 531         }
 532         while ((descr = TAILQ_FIRST(&softc->abort_queue)) != NULL) {
 533                 TAILQ_REMOVE(&softc->abort_queue, descr, tqe);
 534                 free(descr, M_TARG);
 535         }
 536
 537         softc->periph = NULL;
 538         softc->path = NULL;
 539         periph->softc = NULL;
 540 }
 541
 542 /* Receive CCBs from user mode proc and send them to the HBA */
 543 static int
 544 targwrite(struct cdev *dev, struct uio *uio, int ioflag)
 545 {
 546         union ccb *user_ccb;
 547         struct targ_softc *softc;
 548         struct targ_cmd_descr *descr;
 549         int write_len, error;
 550         int func_code, priority;
 551
 552         softc = (struct targ_softc *)dev->si_drv1;
 553         write_len = error = 0;
 554         CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
 555                   ("write - uio_resid %zd\n", uio->uio_resid));
 556         while (uio->uio_resid >= sizeof(user_ccb) && error == 0) {
 557                 union ccb *ccb;
 558
 559                 error = uiomove((caddr_t)&user_ccb, sizeof(user_ccb), uio);
 560                 if (error != 0) {
 561                         CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
 562                                   ("write - uiomove failed (%d)\n", error));
 563                         break;
 564                 }
 565                 priority = fuword32(&user_ccb->ccb_h.pinfo.priority);
 566                 if (priority == CAM_PRIORITY_NONE) {
 567                         error = EINVAL;
 568                         break;
 569                 }
 570                 func_code = fuword32(&user_ccb->ccb_h.func_code);
 571                 switch (func_code) {
 572                 case XPT_ACCEPT_TARGET_IO:
 573                 case XPT_IMMED_NOTIFY:
 574                         cam_periph_lock(softc->periph);
 575                         ccb = targgetccb(softc, func_code, priority);
 576                         descr = (struct targ_cmd_descr *)ccb->ccb_h.targ_descr;
 577                         descr->user_ccb = user_ccb;
 578                         descr->func_code = func_code;
 579                         CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
 580                                   ("Sent ATIO/INOT (%p)\n", user_ccb));
 581                         xpt_action(ccb);
 582                         TAILQ_INSERT_TAIL(&softc->pending_ccb_queue,
 583                                           &ccb->ccb_h,
 584                                           periph_links.tqe);
 585                         cam_periph_unlock(softc->periph);
 586                         break;
 587                 default:
 588                         cam_periph_lock(softc->periph);
 589                         if ((func_code & XPT_FC_QUEUED) != 0) {
 590                                 CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
 591                                           ("Sending queued ccb %#x (%p)\n",
 592                                           func_code, user_ccb));
 593                                 descr = targgetdescr(softc);
 594                                 descr->user_ccb = user_ccb;
 595                                 descr->priority = priority;
 596                                 descr->func_code = func_code;
 597                                 TAILQ_INSERT_TAIL(&softc->work_queue,
 598                                                   descr, tqe);
 599                                 xpt_schedule(softc->periph, priority);
 600                         } else {
 601                                 CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
 602                                           ("Sending inline ccb %#x (%p)\n",
 603                                           func_code, user_ccb));
 604                                 ccb = targgetccb(softc, func_code, priority);
 605                                 descr = (struct targ_cmd_descr *)
 606                                          ccb->ccb_h.targ_descr;
 607                                 descr->user_ccb = user_ccb;
 608                                 descr->priority = priority;
 609                                 descr->func_code = func_code;
 610                                 if (targusermerge(softc, descr, ccb) != EFAULT)
 611                                         targsendccb(softc, ccb, descr);
 612                                 targreturnccb(softc, ccb);
 613                         }
 614                         cam_periph_unlock(softc->periph);
 615                         break;
 616                 }
 617                 write_len += sizeof(user_ccb);
 618         }
 619
 620         /*
 621          * If we've successfully taken in some amount of
 622          * data, return success for that data first.  If
 623          * an error is persistent, it will be reported
 624          * on the next write.
 625          */
 626         if (error != 0 && write_len == 0)
 627                 return (error);
 628         if (write_len == 0 && uio->uio_resid != 0)
 629                 return (ENOSPC);
 630         return (0);
 631 }
 632
 633 /* Process requests (descrs) via the periph-supplied CCBs */
 634 static void
 635 targstart(struct cam_periph *periph, union ccb *start_ccb)
 636 {
 637         struct targ_softc *softc;
 638         struct targ_cmd_descr *descr, *next_descr;
 639         int error;
 640
 641         softc = (struct targ_softc *)periph->softc;
 642         CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("targstart %p\n", start_ccb));
 643
 644         descr = TAILQ_FIRST(&softc->work_queue);
 645         if (descr == NULL) {
 646                 xpt_release_ccb(start_ccb);
 647         } else {
 648                 TAILQ_REMOVE(&softc->work_queue, descr, tqe);
 649                 next_descr = TAILQ_FIRST(&softc->work_queue);
 650
 651                 /* Initiate a transaction using the descr and supplied CCB */
 652                 error = targusermerge(softc, descr, start_ccb);
 653                 if (error == 0)
 654                         error = targsendccb(softc, start_ccb, descr);
 655                 if (error != 0) {
 656                         xpt_print(periph->path,
 657                             "targsendccb failed, err %d\n", error);
 658                         xpt_release_ccb(start_ccb);
 659                         suword(&descr->user_ccb->ccb_h.status,
 660                                CAM_REQ_CMP_ERR);
 661                         TAILQ_INSERT_TAIL(&softc->abort_queue, descr, tqe);
 662                         notify_user(softc);
 663                 }
 664
 665                 /* If we have more work to do, stay scheduled */
 666                 if (next_descr != NULL)
 667                         xpt_schedule(periph, next_descr->priority);
 668         }
 669 }
 670
 671 static int
 672 targusermerge(struct targ_softc *softc, struct targ_cmd_descr *descr,
 673               union ccb *ccb)
 674 {
 675         struct ccb_hdr *u_ccbh, *k_ccbh;
 676         size_t ccb_len;
 677         int error;
 678
 679         u_ccbh = &descr->user_ccb->ccb_h;
 680         k_ccbh = &ccb->ccb_h;
 681
 682         /*
 683          * There are some fields in the CCB header that need to be
 684          * preserved, the rest we get from the user ccb. (See xpt_merge_ccb)
 685          */
 686         xpt_setup_ccb(k_ccbh, softc->path, descr->priority);
 687         k_ccbh->retry_count = fuword32(&u_ccbh->retry_count);
 688         k_ccbh->func_code = descr->func_code;
 689         k_ccbh->flags = fuword32(&u_ccbh->flags);
 690         k_ccbh->timeout = fuword32(&u_ccbh->timeout);
 691         ccb_len = targccblen(k_ccbh->func_code) - sizeof(struct ccb_hdr);
 692         error = copyin(u_ccbh + 1, k_ccbh + 1, ccb_len);
 693         if (error != 0) {
 694                 k_ccbh->status = CAM_REQ_CMP_ERR;
 695                 return (error);
 696         }
 697
 698         /* Translate usermode abort_ccb pointer to its kernel counterpart */
 699         if (k_ccbh->func_code == XPT_ABORT) {
 700                 struct ccb_abort *cab;
 701                 struct ccb_hdr *ccb_h;
 702
 703                 cab = (struct ccb_abort *)ccb;
 704                 TAILQ_FOREACH(ccb_h, &softc->pending_ccb_queue,
 705                     periph_links.tqe) {
 706                         struct targ_cmd_descr *ab_descr;
 707
 708                         ab_descr = (struct targ_cmd_descr *)ccb_h->targ_descr;
 709                         if (ab_descr->user_ccb == cab->abort_ccb) {
 710                                 CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
 711                                           ("Changing abort for %p to %p\n",
 712                                           cab->abort_ccb, ccb_h));
 713                                 cab->abort_ccb = (union ccb *)ccb_h;
 714                                 break;
 715                         }
 716                 }
 717                 /* CCB not found, set appropriate status */
 718                 if (ccb_h == NULL) {
 719                         k_ccbh->status = CAM_PATH_INVALID;
 720                         error = ESRCH;
 721                 }
 722         }
 723
 724         return (error);
 725 }
 726
 727 /* Build and send a kernel CCB formed from descr->user_ccb */
 728 static int
 729 targsendccb(struct targ_softc *softc, union ccb *ccb,
 730             struct targ_cmd_descr *descr)
 731 {
 732         struct cam_periph_map_info *mapinfo;
 733         struct ccb_hdr *ccb_h;
 734         int error;
 735
 736         ccb_h = &ccb->ccb_h;
 737         mapinfo = &descr->mapinfo;
 738         mapinfo->num_bufs_used = 0;
 739
 740         /*
 741          * There's no way for the user to have a completion
 742          * function, so we put our own completion function in here.
 743          * We also stash in a reference to our descriptor so targreturnccb()
 744          * can find our mapping info.
 745          */
 746         ccb_h->cbfcnp = targdone;
 747         ccb_h->targ_descr = descr;
 748
 749         /*
 750          * We only attempt to map the user memory into kernel space
 751          * if they haven't passed in a physical memory pointer,
 752          * and if there is actually an I/O operation to perform.
 753          * Right now cam_periph_mapmem() only supports SCSI and device
 754          * match CCBs.  For the SCSI CCBs, we only pass the CCB in if
 755          * there's actually data to map.  cam_periph_mapmem() will do the
 756          * right thing, even if there isn't data to map, but since CCBs
 757          * without data are a reasonably common occurance (e.g. test unit
 758          * ready), it will save a few cycles if we check for it here.
 759          */
 760         if (((ccb_h->flags & CAM_DATA_PHYS) == 0)
 761          && (((ccb_h->func_code == XPT_CONT_TARGET_IO)
 762             && ((ccb_h->flags & CAM_DIR_MASK) != CAM_DIR_NONE))
 763           || (ccb_h->func_code == XPT_DEV_MATCH))) {
 764
 765                 error = cam_periph_mapmem(ccb, mapinfo);
 766
 767                 /*
 768                  * cam_periph_mapmem returned an error, we can't continue.
 769                  * Return the error to the user.
 770                  */
 771                 if (error) {
 772                         ccb_h->status = CAM_REQ_CMP_ERR;
 773                         mapinfo->num_bufs_used = 0;
 774                         return (error);
 775                 }
 776         }
 777
 778         /*
 779          * Once queued on the pending CCB list, this CCB will be protected
 780          * by our error recovery handler.
 781          */
 782         CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("sendccb %p\n", ccb));
 783         if (XPT_FC_IS_QUEUED(ccb)) {
 784                 TAILQ_INSERT_TAIL(&softc->pending_ccb_queue, ccb_h,
 785                                   periph_links.tqe);
 786         }
 787         xpt_action(ccb);
 788
 789         return (0);
 790 }
 791
 792 /* Completion routine for CCBs (called at splsoftcam) */
 793 static void
 794 targdone(struct cam_periph *periph, union ccb *done_ccb)
 795 {
 796         struct targ_softc *softc;
 797         cam_status status;
 798
 799         CAM_DEBUG(periph->path, CAM_DEBUG_PERIPH, ("targdone %p\n", done_ccb));
 800         softc = (struct targ_softc *)periph->softc;
 801         TAILQ_REMOVE(&softc->pending_ccb_queue, &done_ccb->ccb_h,
 802                      periph_links.tqe);
 803         status = done_ccb->ccb_h.status & CAM_STATUS_MASK;
 804
 805         /* If we're no longer enabled, throw away CCB */
 806         if ((softc->state & TARG_STATE_LUN_ENABLED) == 0) {
 807                 targfreeccb(softc, done_ccb);
 808                 return;
 809         }
 810         /* abort_all_pending() waits for pending queue to be empty */
 811         if (TAILQ_EMPTY(&softc->pending_ccb_queue))
 812                 wakeup(&softc->pending_ccb_queue);
 813
 814         switch (done_ccb->ccb_h.func_code) {
 815         /* All FC_*_QUEUED CCBs go back to userland */
 816         case XPT_IMMED_NOTIFY:
 817         case XPT_ACCEPT_TARGET_IO:
 818         case XPT_CONT_TARGET_IO:
 819                 TAILQ_INSERT_TAIL(&softc->user_ccb_queue, &done_ccb->ccb_h,
 820                                   periph_links.tqe);
 821                 notify_user(softc);
 822                 break;
 823         default:
 824                 panic("targdone: impossible xpt opcode %#x",
 825                       done_ccb->ccb_h.func_code);
 826                 /* NOTREACHED */
 827         }
 828 }
 829
 830 /* Return CCBs to the user from the user queue and abort queue */
 831 static int
 832 targread(struct cdev *dev, struct uio *uio, int ioflag)
 833 {
 834         struct descr_queue      *abort_queue;
 835         struct targ_cmd_descr   *user_descr;
 836         struct targ_softc       *softc;
 837         struct ccb_queue  *user_queue;
 838         struct ccb_hdr    *ccb_h;
 839         union  ccb        *user_ccb;
 840         int                read_len, error;
 841
 842         error = 0;
 843         read_len = 0;
 844         softc = (struct targ_softc *)dev->si_drv1;
 845         user_queue = &softc->user_ccb_queue;
 846         abort_queue = &softc->abort_queue;
 847         CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("targread\n"));
 848
 849         /* If no data is available, wait or return immediately */
 850         cam_periph_lock(softc->periph);
 851         ccb_h = TAILQ_FIRST(user_queue);
 852         user_descr = TAILQ_FIRST(abort_queue);
 853         while (ccb_h == NULL && user_descr == NULL) {
 854                 if ((ioflag & IO_NDELAY) == 0) {
 855                         error = msleep(user_queue, softc->periph->sim->mtx,
 856                             PRIBIO | PCATCH, "targrd", 0);
 857                         ccb_h = TAILQ_FIRST(user_queue);
 858                         user_descr = TAILQ_FIRST(abort_queue);
 859                         if (error != 0) {
 860                                 if (error == ERESTART) {
 861                                         continue;
 862                                 } else {
 863                                         goto read_fail;
 864                                 }
 865                         }
 866                 } else {
 867                         cam_periph_unlock(softc->periph);
 868                         return (EAGAIN);
 869                 }
 870         }
 871
 872         /* Data is available so fill the user's buffer */
 873         while (ccb_h != NULL) {
 874                 struct targ_cmd_descr *descr;
 875
 876                 if (uio->uio_resid < sizeof(user_ccb))
 877                         break;
 878                 TAILQ_REMOVE(user_queue, ccb_h, periph_links.tqe);
 879                 descr = (struct targ_cmd_descr *)ccb_h->targ_descr;
 880                 user_ccb = descr->user_ccb;
 881                 CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
 882                           ("targread ccb %p (%p)\n", ccb_h, user_ccb));
 883                 error = targreturnccb(softc, (union ccb *)ccb_h);
 884                 if (error != 0)
 885                         goto read_fail;
 886                 cam_periph_unlock(softc->periph);
 887                 error = uiomove((caddr_t)&user_ccb, sizeof(user_ccb), uio);
 888                 cam_periph_lock(softc->periph);
 889                 if (error != 0)
 890                         goto read_fail;
 891                 read_len += sizeof(user_ccb);
 892
 893                 ccb_h = TAILQ_FIRST(user_queue);
 894         }
 895
 896         /* Flush out any aborted descriptors */
 897         while (user_descr != NULL) {
 898                 if (uio->uio_resid < sizeof(user_ccb))
 899                         break;
 900                 TAILQ_REMOVE(abort_queue, user_descr, tqe);
 901                 user_ccb = user_descr->user_ccb;
 902                 CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
 903                           ("targread aborted descr %p (%p)\n",
 904                           user_descr, user_ccb));
 905                 suword(&user_ccb->ccb_h.status, CAM_REQ_ABORTED);
 906                 cam_periph_unlock(softc->periph);
 907                 error = uiomove((caddr_t)&user_ccb, sizeof(user_ccb), uio);
 908                 cam_periph_lock(softc->periph);
 909                 if (error != 0)
 910                         goto read_fail;
 911                 read_len += sizeof(user_ccb);
 912
 913                 user_descr = TAILQ_FIRST(abort_queue);
 914         }
 915
 916         /*
 917          * If we've successfully read some amount of data, don't report an
 918          * error.  If the error is persistent, it will be reported on the
 919          * next read().
 920          */
 921         if (read_len == 0 && uio->uio_resid != 0)
 922                 error = ENOSPC;
 923
 924 read_fail:
 925         cam_periph_unlock(softc->periph);
 926         return (error);
 927 }
 928
 929 /* Copy completed ccb back to the user */
 930 static int
 931 targreturnccb(struct targ_softc *softc, union ccb *ccb)
 932 {
 933         struct targ_cmd_descr *descr;
 934         struct ccb_hdr *u_ccbh;
 935         size_t ccb_len;
 936         int error;
 937
 938         CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("targreturnccb %p\n", ccb));
 939         descr = (struct targ_cmd_descr *)ccb->ccb_h.targ_descr;
 940         u_ccbh = &descr->user_ccb->ccb_h;
 941
 942         /* Copy out the central portion of the ccb_hdr */
 943         copyout(&ccb->ccb_h.retry_count, &u_ccbh->retry_count,
 944                 offsetof(struct ccb_hdr, periph_priv) -
 945                 offsetof(struct ccb_hdr, retry_count));
 946
 947         /* Copy out the rest of the ccb (after the ccb_hdr) */
 948         ccb_len = targccblen(ccb->ccb_h.func_code) - sizeof(struct ccb_hdr);
 949         if (descr->mapinfo.num_bufs_used != 0)
 950                 cam_periph_unmapmem(ccb, &descr->mapinfo);
 951         error = copyout(&ccb->ccb_h + 1, u_ccbh + 1, ccb_len);
 952         if (error != 0) {
 953                 xpt_print(softc->path,
 954                     "targreturnccb - CCB copyout failed (%d)\n", error);
 955         }
 956         /* Free CCB or send back to devq. */
 957         targfreeccb(softc, ccb);
 958
 959         return (error);
 960 }
 961
 962 static union ccb *
 963 targgetccb(struct targ_softc *softc, xpt_opcode type, int priority)
 964 {
 965         union ccb *ccb;
 966         int ccb_len;
 967
 968         ccb_len = targccblen(type);
 969         ccb = malloc(ccb_len, M_TARG, M_WAITOK);
 970         CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("getccb %p\n", ccb));
 971
 972         xpt_setup_ccb(&ccb->ccb_h, softc->path, priority);
 973         ccb->ccb_h.func_code = type;
 974         ccb->ccb_h.cbfcnp = targdone;
 975         ccb->ccb_h.targ_descr = targgetdescr(softc);
 976         return (ccb);
 977 }
 978
 979 static void
 980 targfreeccb(struct targ_softc *softc, union ccb *ccb)
 981 {
 982         CAM_DEBUG_PRINT(CAM_DEBUG_PERIPH, ("targfreeccb descr %p and\n",
 983                         ccb->ccb_h.targ_descr));
 984         free(ccb->ccb_h.targ_descr, M_TARG);
 985
 986         switch (ccb->ccb_h.func_code) {
 987         case XPT_ACCEPT_TARGET_IO:
 988         case XPT_IMMED_NOTIFY:
 989                 CAM_DEBUG_PRINT(CAM_DEBUG_PERIPH, ("freeing ccb %p\n", ccb));
 990                 free(ccb, M_TARG);
 991                 break;
 992         default:
 993                 /* Send back CCB if we got it from the periph */
 994                 if (XPT_FC_IS_QUEUED(ccb)) {
 995                         CAM_DEBUG_PRINT(CAM_DEBUG_PERIPH,
 996                                         ("returning queued ccb %p\n", ccb));
 997                         xpt_release_ccb(ccb);
 998                 } else {
 999                         CAM_DEBUG_PRINT(CAM_DEBUG_PERIPH,
1000                                         ("freeing ccb %p\n", ccb));
1001                         free(ccb, M_TARG);
1002                 }
1003                 break;
1004         }
1005 }
1006
1007 static struct targ_cmd_descr *
1008 targgetdescr(struct targ_softc *softc)
1009 {
1010         struct targ_cmd_descr *descr;
1011
1012         descr = malloc(sizeof(*descr), M_TARG,
1013                M_WAITOK);
1014         descr->mapinfo.num_bufs_used = 0;
1015         return (descr);
1016 }
1017
1018 static void
1019 targinit(void)
1020 {
1021         EVENTHANDLER_REGISTER(dev_clone, targclone, 0, 1000);
1022 }
1023
1024 static void
1025 targclone(void *arg, struct ucred *cred, char *name, int namelen,
1026     struct cdev **dev)
1027 {
1028         int u;
1029
1030         if (*dev != NULL)
1031                 return;
1032         if (dev_stdclone(name, NULL, "targ", &u) != 1)
1033                 return;
1034         *dev = make_dev(&targ_cdevsw, u, UID_ROOT, GID_WHEEL,
1035                         0600, "targ%d", u);
1036         dev_ref(*dev);
1037         (*dev)->si_flags |= SI_CHEAPCLONE;
1038 }
1039
1040 static void
1041 targasync(void *callback_arg, u_int32_t code, struct cam_path *path, void *arg)
1042 {
1043         /* All events are handled in usermode by INOTs */
1044         panic("targasync() called, should be an INOT instead");
1045 }
1046
1047 /* Cancel all pending requests and CCBs awaiting work. */
1048 static void
1049 abort_all_pending(struct targ_softc *softc)
1050 {
1051         struct targ_cmd_descr   *descr;
1052         struct ccb_abort         cab;
1053         struct ccb_hdr          *ccb_h;
1054         struct cam_sim          *sim;
1055
1056         CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH, ("abort_all_pending\n"));
1057
1058         /* First abort the descriptors awaiting resources */
1059         while ((descr = TAILQ_FIRST(&softc->work_queue)) != NULL) {
1060                 CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
1061                           ("Aborting descr from workq %p\n", descr));
1062                 TAILQ_REMOVE(&softc->work_queue, descr, tqe);
1063                 TAILQ_INSERT_TAIL(&softc->abort_queue, descr, tqe);
1064         }
1065
1066         /*
1067          * Then abort all pending CCBs.
1068          * targdone() will return the aborted CCB via user_ccb_queue
1069          */
1070         xpt_setup_ccb(&cab.ccb_h, softc->path, CAM_PRIORITY_NORMAL);
1071         cab.ccb_h.func_code = XPT_ABORT;
1072         cab.ccb_h.status = CAM_REQ_CMP_ERR;
1073         TAILQ_FOREACH(ccb_h, &softc->pending_ccb_queue, periph_links.tqe) {
1074                 CAM_DEBUG(softc->path, CAM_DEBUG_PERIPH,
1075                           ("Aborting pending CCB %p\n", ccb_h));
1076                 cab.abort_ccb = (union ccb *)ccb_h;
1077                 xpt_action((union ccb *)&cab);
1078                 if (cab.ccb_h.status != CAM_REQ_CMP) {
1079                         xpt_print(cab.ccb_h.path,
1080                             "Unable to abort CCB, status %#x\n",
1081                             cab.ccb_h.status);
1082                 }
1083         }
1084
1085         /* If we aborted at least one pending CCB ok, wait for it. */
1086         if (cab.ccb_h.status == CAM_REQ_CMP) {
1087                 sim = xpt_path_sim(softc->path);
1088                 msleep(&softc->pending_ccb_queue, sim->mtx,
1089                        PRIBIO | PCATCH, "tgabrt", 0);
1090         }
1091
1092         /* If we aborted anything from the work queue, wakeup user. */
1093         if (!TAILQ_EMPTY(&softc->user_ccb_queue)
1094          || !TAILQ_EMPTY(&softc->abort_queue))
1095                 notify_user(softc);
1096 }
1097
1098 /* Notify the user that data is ready */
1099 static void
1100 notify_user(struct targ_softc *softc)
1101 {
1102         /*
1103          * Notify users sleeping via poll(), kqueue(), and
1104          * blocking read().
1105          */
1106         selwakeuppri(&softc->read_select, PRIBIO);
1107         KNOTE_UNLOCKED(&softc->read_select.si_note, 0);
1108         wakeup(&softc->user_ccb_queue);
1109 }
1110
1111 /* Convert CAM status to errno values */
1112 static int
1113 targcamstatus(cam_status status)
1114 {
1115         switch (status & CAM_STATUS_MASK) {
1116         case CAM_REQ_CMP:       /* CCB request completed without error */
1117                 return (0);
1118         case CAM_REQ_INPROG:    /* CCB request is in progress */
1119                 return (EINPROGRESS);
1120         case CAM_REQ_CMP_ERR:   /* CCB request completed with an error */
1121                 return (EIO);
1122         case CAM_PROVIDE_FAIL:  /* Unable to provide requested capability */
1123                 return (ENOTTY);
1124         case CAM_FUNC_NOTAVAIL: /* The requested function is not available */
1125                 return (ENOTSUP);
1126         case CAM_LUN_ALRDY_ENA: /* LUN is already enabled for target mode */
1127                 return (EADDRINUSE);
1128         case CAM_PATH_INVALID:  /* Supplied Path ID is invalid */
1129         case CAM_DEV_NOT_THERE: /* SCSI Device Not Installed/there */
1130                 return (ENOENT);
1131         case CAM_REQ_ABORTED:   /* CCB request aborted by the host */
1132                 return (ECANCELED);
1133         case CAM_CMD_TIMEOUT:   /* Command timeout */
1134                 return (ETIMEDOUT);
1135         case CAM_REQUEUE_REQ:   /* Requeue to preserve transaction ordering */
1136                 return (EAGAIN);
1137         case CAM_REQ_INVALID:   /* CCB request was invalid */
1138                 return (EINVAL);
1139         case CAM_RESRC_UNAVAIL: /* Resource Unavailable */
1140                 return (ENOMEM);
1141         case CAM_BUSY:          /* CAM subsytem is busy */
1142         case CAM_UA_ABORT:      /* Unable to abort CCB request */
1143                 return (EBUSY);
1144         default:
1145                 return (ENXIO);
1146         }
1147 }
1148
1149 static size_t
1150 targccblen(xpt_opcode func_code)
1151 {
1152         int len;
1153
1154         /* Codes we expect to see as a target */
1155         switch (func_code) {
1156         case XPT_CONT_TARGET_IO:
1157         case XPT_SCSI_IO:
1158                 len = sizeof(struct ccb_scsiio);
1159                 break;
1160         case XPT_ACCEPT_TARGET_IO:
1161                 len = sizeof(struct ccb_accept_tio);
1162                 break;
1163         case XPT_IMMED_NOTIFY:
1164                 len = sizeof(struct ccb_immed_notify);
1165                 break;
1166         case XPT_REL_SIMQ:
1167                 len = sizeof(struct ccb_relsim);
1168                 break;
1169         case XPT_PATH_INQ:
1170                 len = sizeof(struct ccb_pathinq);
1171                 break;
1172         case XPT_DEBUG:
1173                 len = sizeof(struct ccb_debug);
1174                 break;
1175         case XPT_ABORT:
1176                 len = sizeof(struct ccb_abort);
1177                 break;
1178         case XPT_EN_LUN:
1179                 len = sizeof(struct ccb_en_lun);
1180                 break;
1181         default:
1182                 len = sizeof(union ccb);
1183                 break;
1184         }
1185
1186         return (len);
1187 }