drivers/xen/xen-scsiback.c

   1 /*
   2  * Xen SCSI backend driver
   3  *
   4  * Copyright (c) 2008, FUJITSU Limited
   5  *
   6  * Based on the blkback driver code.
   7  * Adaption to kernel taget core infrastructure taken from vhost/scsi.c
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License version 2
  11  * as published by the Free Software Foundation; or, when distributed
  12  * separately from the Linux kernel or incorporated into other
  13  * software packages, subject to the following license:
  14  *
  15  * Permission is hereby granted, free of charge, to any person obtaining a copy
  16  * of this source file (the "Software"), to deal in the Software without
  17  * restriction, including without limitation the rights to use, copy, modify,
  18  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  19  * and to permit persons to whom the Software is furnished to do so, subject to
  20  * the following conditions:
  21  *
  22  * The above copyright notice and this permission notice shall be included in
  23  * all copies or substantial portions of the Software.
  24  *
  25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  26  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  27  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  28  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  29  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  30  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  31  * IN THE SOFTWARE.
  32  */
  33
  34 #define pr_fmt(fmt) "xen-pvscsi: " fmt
  35
  36 #include <stdarg.h>
  37
  38 #include <linux/module.h>
  39 #include <linux/utsname.h>
  40 #include <linux/interrupt.h>
  41 #include <linux/slab.h>
  42 #include <linux/wait.h>
  43 #include <linux/sched.h>
  44 #include <linux/list.h>
  45 #include <linux/gfp.h>
  46 #include <linux/delay.h>
  47 #include <linux/spinlock.h>
  48 #include <linux/configfs.h>
  49
  50 #include <generated/utsrelease.h>
  51
  52 #include <scsi/scsi.h>
  53 #include <scsi/scsi_dbg.h>
  54 #include <scsi/scsi_eh.h>
  55 #include <scsi/scsi_tcq.h>
  56
  57 #include <target/target_core_base.h>
  58 #include <target/target_core_fabric.h>
  59 #include <target/target_core_fabric_configfs.h>
  60
  61 #include <asm/hypervisor.h>
  62
  63 #include <xen/xen.h>
  64 #include <xen/balloon.h>
  65 #include <xen/events.h>
  66 #include <xen/xenbus.h>
  67 #include <xen/grant_table.h>
  68 #include <xen/page.h>
  69
  70 #include <xen/interface/grant_table.h>
  71 #include <xen/interface/io/vscsiif.h>
  72
  73 #define VSCSI_VERSION   "v0.1"
  74 #define VSCSI_NAMELEN   32
  75
  76 struct ids_tuple {
  77         unsigned int hst;               /* host    */
  78         unsigned int chn;               /* channel */
  79         unsigned int tgt;               /* target  */
  80         unsigned int lun;               /* LUN     */
  81 };
  82
  83 struct v2p_entry {
  84         struct ids_tuple v;             /* translate from */
  85         struct scsiback_tpg *tpg;       /* translate to   */
  86         unsigned int lun;
  87         struct kref kref;
  88         struct list_head l;
  89 };
  90
  91 struct vscsibk_info {
  92         struct xenbus_device *dev;
  93
  94         domid_t domid;
  95         unsigned int irq;
  96
  97         struct vscsiif_back_ring ring;
  98         int ring_error;
  99
 100         spinlock_t ring_lock;
 101         atomic_t nr_unreplied_reqs;
 102
 103         spinlock_t v2p_lock;
 104         struct list_head v2p_entry_lists;
 105
 106         wait_queue_head_t waiting_to_free;
 107 };
 108
 109 /* theoretical maximum of grants for one request */
 110 #define VSCSI_MAX_GRANTS        (SG_ALL + VSCSIIF_SG_TABLESIZE)
 111
 112 /*
 113  * VSCSI_GRANT_BATCH is the maximum number of grants to be processed in one
 114  * call to map/unmap grants. Don't choose it too large, as there are arrays
 115  * with VSCSI_GRANT_BATCH elements allocated on the stack.
 116  */
 117 #define VSCSI_GRANT_BATCH       16
 118
 119 struct vscsibk_pend {
 120         uint16_t rqid;
 121
 122         uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE];
 123         uint8_t cmd_len;
 124
 125         uint8_t sc_data_direction;
 126         uint16_t n_sg;          /* real length of SG list */
 127         uint16_t n_grants;      /* SG pages and potentially SG list */
 128         uint32_t data_len;
 129         uint32_t result;
 130
 131         struct vscsibk_info *info;
 132         struct v2p_entry *v2p;
 133         struct scatterlist *sgl;
 134
 135         uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];
 136
 137         grant_handle_t grant_handles[VSCSI_MAX_GRANTS];
 138         struct page *pages[VSCSI_MAX_GRANTS];
 139
 140         struct se_cmd se_cmd;
 141 };
 142
 143 struct scsiback_tmr {
 144         atomic_t tmr_complete;
 145         wait_queue_head_t tmr_wait;
 146 };
 147
 148 struct scsiback_nexus {
 149         /* Pointer to TCM session for I_T Nexus */
 150         struct se_session *tvn_se_sess;
 151 };
 152
 153 struct scsiback_tport {
 154         /* SCSI protocol the tport is providing */
 155         u8 tport_proto_id;
 156         /* Binary World Wide unique Port Name for pvscsi Target port */
 157         u64 tport_wwpn;
 158         /* ASCII formatted WWPN for pvscsi Target port */
 159         char tport_name[VSCSI_NAMELEN];
 160         /* Returned by scsiback_make_tport() */
 161         struct se_wwn tport_wwn;
 162 };
 163
 164 struct scsiback_tpg {
 165         /* scsiback port target portal group tag for TCM */
 166         u16 tport_tpgt;
 167         /* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
 168         int tv_tpg_port_count;
 169         /* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
 170         int tv_tpg_fe_count;
 171         /* list for scsiback_list */
 172         struct list_head tv_tpg_list;
 173         /* Used to protect access for tpg_nexus */
 174         struct mutex tv_tpg_mutex;
 175         /* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
 176         struct scsiback_nexus *tpg_nexus;
 177         /* Pointer back to scsiback_tport */
 178         struct scsiback_tport *tport;
 179         /* Returned by scsiback_make_tpg() */
 180         struct se_portal_group se_tpg;
 181         /* alias used in xenstore */
 182         char param_alias[VSCSI_NAMELEN];
 183         /* list of info structures related to this target portal group */
 184         struct list_head info_list;
 185 };
 186
 187 #define SCSIBACK_INVALID_HANDLE (~0)
 188
 189 static bool log_print_stat;
 190 module_param(log_print_stat, bool, 0644);
 191
 192 static int scsiback_max_buffer_pages = 1024;
 193 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
 194 MODULE_PARM_DESC(max_buffer_pages,
 195 "Maximum number of free pages to keep in backend buffer");
 196
 197 static struct kmem_cache *scsiback_cachep;
 198 static DEFINE_SPINLOCK(free_pages_lock);
 199 static int free_pages_num;
 200 static LIST_HEAD(scsiback_free_pages);
 201
 202 /* Global spinlock to protect scsiback TPG list */
 203 static DEFINE_MUTEX(scsiback_mutex);
 204 static LIST_HEAD(scsiback_list);
 205
 206 static const struct target_core_fabric_ops scsiback_ops;
 207
 208 static void scsiback_get(struct vscsibk_info *info)
 209 {
 210         atomic_inc(&info->nr_unreplied_reqs);
 211 }
 212
 213 static void scsiback_put(struct vscsibk_info *info)
 214 {
 215         if (atomic_dec_and_test(&info->nr_unreplied_reqs))
 216                 wake_up(&info->waiting_to_free);
 217 }
 218
 219 static void put_free_pages(struct page **page, int num)
 220 {
 221         unsigned long flags;
 222         int i = free_pages_num + num, n = num;
 223
 224         if (num == 0)
 225                 return;
 226         if (i > scsiback_max_buffer_pages) {
 227                 n = min(num, i - scsiback_max_buffer_pages);
 228                 gnttab_free_pages(n, page + num - n);
 229                 n = num - n;
 230         }
 231         spin_lock_irqsave(&free_pages_lock, flags);
 232         for (i = 0; i < n; i++)
 233                 list_add(&page[i]->lru, &scsiback_free_pages);
 234         free_pages_num += n;
 235         spin_unlock_irqrestore(&free_pages_lock, flags);
 236 }
 237
 238 static int get_free_page(struct page **page)
 239 {
 240         unsigned long flags;
 241
 242         spin_lock_irqsave(&free_pages_lock, flags);
 243         if (list_empty(&scsiback_free_pages)) {
 244                 spin_unlock_irqrestore(&free_pages_lock, flags);
 245                 return gnttab_alloc_pages(1, page);
 246         }
 247         page[0] = list_first_entry(&scsiback_free_pages, struct page, lru);
 248         list_del(&page[0]->lru);
 249         free_pages_num--;
 250         spin_unlock_irqrestore(&free_pages_lock, flags);
 251         return 0;
 252 }
 253
 254 static unsigned long vaddr_page(struct page *page)
 255 {
 256         unsigned long pfn = page_to_pfn(page);
 257
 258         return (unsigned long)pfn_to_kaddr(pfn);
 259 }
 260
 261 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
 262 {
 263         return vaddr_page(req->pages[seg]);
 264 }
 265
 266 static void scsiback_print_status(char *sense_buffer, int errors,
 267                                         struct vscsibk_pend *pending_req)
 268 {
 269         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 270
 271         pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
 272                tpg->tport->tport_name, pending_req->v2p->lun,
 273                pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
 274                host_byte(errors), driver_byte(errors));
 275 }
 276
 277 static void scsiback_fast_flush_area(struct vscsibk_pend *req)
 278 {
 279         struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
 280         struct page *pages[VSCSI_GRANT_BATCH];
 281         unsigned int i, invcount = 0;
 282         grant_handle_t handle;
 283         int err;
 284
 285         kfree(req->sgl);
 286         req->sgl = NULL;
 287         req->n_sg = 0;
 288
 289         if (!req->n_grants)
 290                 return;
 291
 292         for (i = 0; i < req->n_grants; i++) {
 293                 handle = req->grant_handles[i];
 294                 if (handle == SCSIBACK_INVALID_HANDLE)
 295                         continue;
 296                 gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
 297                                     GNTMAP_host_map, handle);
 298                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 299                 pages[invcount] = req->pages[i];
 300                 put_page(pages[invcount]);
 301                 invcount++;
 302                 if (invcount < VSCSI_GRANT_BATCH)
 303                         continue;
 304                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 305                 BUG_ON(err);
 306                 invcount = 0;
 307         }
 308
 309         if (invcount) {
 310                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 311                 BUG_ON(err);
 312         }
 313
 314         put_free_pages(req->pages, req->n_grants);
 315         req->n_grants = 0;
 316 }
 317
 318 static void scsiback_free_translation_entry(struct kref *kref)
 319 {
 320         struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
 321         struct scsiback_tpg *tpg = entry->tpg;
 322
 323         mutex_lock(&tpg->tv_tpg_mutex);
 324         tpg->tv_tpg_fe_count--;
 325         mutex_unlock(&tpg->tv_tpg_mutex);
 326
 327         kfree(entry);
 328 }
 329
 330 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
 331                         uint32_t resid, struct vscsibk_pend *pending_req)
 332 {
 333         struct vscsiif_response *ring_res;
 334         struct vscsibk_info *info = pending_req->info;
 335         int notify;
 336         struct scsi_sense_hdr sshdr;
 337         unsigned long flags;
 338         unsigned len;
 339
 340         spin_lock_irqsave(&info->ring_lock, flags);
 341
 342         ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
 343         info->ring.rsp_prod_pvt++;
 344
 345         ring_res->rslt   = result;
 346         ring_res->rqid   = pending_req->rqid;
 347
 348         if (sense_buffer != NULL &&
 349             scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
 350                                  &sshdr)) {
 351                 len = min_t(unsigned, 8 + sense_buffer[7],
 352                             VSCSIIF_SENSE_BUFFERSIZE);
 353                 memcpy(ring_res->sense_buffer, sense_buffer, len);
 354                 ring_res->sense_len = len;
 355         } else {
 356                 ring_res->sense_len = 0;
 357         }
 358
 359         ring_res->residual_len = resid;
 360
 361         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
 362         spin_unlock_irqrestore(&info->ring_lock, flags);
 363
 364         if (notify)
 365                 notify_remote_via_irq(info->irq);
 366
 367         if (pending_req->v2p)
 368                 kref_put(&pending_req->v2p->kref,
 369                          scsiback_free_translation_entry);
 370 }
 371
 372 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
 373 {
 374         struct vscsibk_info *info = pending_req->info;
 375         unsigned char *sense_buffer;
 376         unsigned int resid;
 377         int errors;
 378
 379         sense_buffer = pending_req->sense_buffer;
 380         resid        = pending_req->se_cmd.residual_count;
 381         errors       = pending_req->result;
 382
 383         if (errors && log_print_stat)
 384                 scsiback_print_status(sense_buffer, errors, pending_req);
 385
 386         scsiback_fast_flush_area(pending_req);
 387         scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
 388         scsiback_put(info);
 389 }
 390
 391 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
 392 {
 393         struct se_cmd *se_cmd = &pending_req->se_cmd;
 394         struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
 395         int rc;
 396
 397         memset(pending_req->sense_buffer, 0, VSCSIIF_SENSE_BUFFERSIZE);
 398
 399         memset(se_cmd, 0, sizeof(*se_cmd));
 400
 401         scsiback_get(pending_req->info);
 402         se_cmd->tag = pending_req->rqid;
 403         rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,
 404                         pending_req->sense_buffer, pending_req->v2p->lun,
 405                         pending_req->data_len, 0,
 406                         pending_req->sc_data_direction, 0,
 407                         pending_req->sgl, pending_req->n_sg,
 408                         NULL, 0, NULL, 0);
 409         if (rc < 0) {
 410                 transport_send_check_condition_and_sense(se_cmd,
 411                                 TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
 412                 transport_generic_free_cmd(se_cmd, 0);
 413         }
 414 }
 415
 416 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 417         struct page **pg, grant_handle_t *grant, int cnt)
 418 {
 419         int err, i;
 420
 421         if (!cnt)
 422                 return 0;
 423
 424         err = gnttab_map_refs(map, NULL, pg, cnt);
 425         BUG_ON(err);
 426         for (i = 0; i < cnt; i++) {
 427                 if (unlikely(map[i].status != GNTST_okay)) {
 428                         pr_err("invalid buffer -- could not remap it\n");
 429                         map[i].handle = SCSIBACK_INVALID_HANDLE;
 430                         err = -ENOMEM;
 431                 } else {
 432                         get_page(pg[i]);
 433                 }
 434                 grant[i] = map[i].handle;
 435         }
 436         return err;
 437 }
 438
 439 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
 440                         struct scsiif_request_segment *seg, struct page **pg,
 441                         grant_handle_t *grant, int cnt, u32 flags)
 442 {
 443         int mapcount = 0, i, err = 0;
 444         struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
 445         struct vscsibk_info *info = pending_req->info;
 446
 447         for (i = 0; i < cnt; i++) {
 448                 if (get_free_page(pg + mapcount)) {
 449                         put_free_pages(pg, mapcount);
 450                         pr_err("no grant page\n");
 451                         return -ENOMEM;
 452                 }
 453                 gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
 454                                   flags, seg[i].gref, info->domid);
 455                 mapcount++;
 456                 if (mapcount < VSCSI_GRANT_BATCH)
 457                         continue;
 458                 err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 459                 pg += mapcount;
 460                 grant += mapcount;
 461                 pending_req->n_grants += mapcount;
 462                 if (err)
 463                         return err;
 464                 mapcount = 0;
 465         }
 466         err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 467         pending_req->n_grants += mapcount;
 468         return err;
 469 }
 470
 471 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 472                                         struct vscsibk_pend *pending_req)
 473 {
 474         u32 flags;
 475         int i, err, n_segs, i_seg = 0;
 476         struct page **pg;
 477         struct scsiif_request_segment *seg;
 478         unsigned long end_seg = 0;
 479         unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
 480         unsigned int nr_sgl = 0;
 481         struct scatterlist *sg;
 482         grant_handle_t *grant;
 483
 484         pending_req->n_sg = 0;
 485         pending_req->n_grants = 0;
 486         pending_req->data_len = 0;
 487
 488         nr_segments &= ~VSCSIIF_SG_GRANT;
 489         if (!nr_segments)
 490                 return 0;
 491
 492         if (nr_segments > VSCSIIF_SG_TABLESIZE) {
 493                 pr_debug("invalid parameter nr_seg = %d\n",
 494                         ring_req->nr_segments);
 495                 return -EINVAL;
 496         }
 497
 498         if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
 499                 err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
 500                         pending_req->pages, pending_req->grant_handles,
 501                         nr_segments, GNTMAP_host_map | GNTMAP_readonly);
 502                 if (err)
 503                         return err;
 504                 nr_sgl = nr_segments;
 505                 nr_segments = 0;
 506                 for (i = 0; i < nr_sgl; i++) {
 507                         n_segs = ring_req->seg[i].length /
 508                                  sizeof(struct scsiif_request_segment);
 509                         if ((unsigned)ring_req->seg[i].offset +
 510                             (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
 511                             n_segs * sizeof(struct scsiif_request_segment) !=
 512                             ring_req->seg[i].length)
 513                                 return -EINVAL;
 514                         nr_segments += n_segs;
 515                 }
 516                 if (nr_segments > SG_ALL) {
 517                         pr_debug("invalid nr_seg = %d\n", nr_segments);
 518                         return -EINVAL;
 519                 }
 520         }
 521
 522         /* free of (sgl) in fast_flush_area() */
 523         pending_req->sgl = kmalloc_array(nr_segments,
 524                                         sizeof(struct scatterlist), GFP_KERNEL);
 525         if (!pending_req->sgl)
 526                 return -ENOMEM;
 527
 528         sg_init_table(pending_req->sgl, nr_segments);
 529         pending_req->n_sg = nr_segments;
 530
 531         flags = GNTMAP_host_map;
 532         if (pending_req->sc_data_direction == DMA_TO_DEVICE)
 533                 flags |= GNTMAP_readonly;
 534
 535         pg = pending_req->pages + nr_sgl;
 536         grant = pending_req->grant_handles + nr_sgl;
 537         if (!nr_sgl) {
 538                 seg = ring_req->seg;
 539                 err = scsiback_gnttab_data_map_list(pending_req, seg,
 540                         pg, grant, nr_segments, flags);
 541                 if (err)
 542                         return err;
 543         } else {
 544                 for (i = 0; i < nr_sgl; i++) {
 545                         seg = (struct scsiif_request_segment *)(
 546                               vaddr(pending_req, i) + ring_req->seg[i].offset);
 547                         n_segs = ring_req->seg[i].length /
 548                                  sizeof(struct scsiif_request_segment);
 549                         err = scsiback_gnttab_data_map_list(pending_req, seg,
 550                                 pg, grant, n_segs, flags);
 551                         if (err)
 552                                 return err;
 553                         pg += n_segs;
 554                         grant += n_segs;
 555                 }
 556                 end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
 557                 seg = (struct scsiif_request_segment *)end_seg;
 558                 end_seg += ring_req->seg[0].length;
 559                 pg = pending_req->pages + nr_sgl;
 560         }
 561
 562         for_each_sg(pending_req->sgl, sg, nr_segments, i) {
 563                 sg_set_page(sg, pg[i], seg->length, seg->offset);
 564                 pending_req->data_len += seg->length;
 565                 seg++;
 566                 if (nr_sgl && (unsigned long)seg >= end_seg) {
 567                         i_seg++;
 568                         end_seg = vaddr(pending_req, i_seg) +
 569                                   ring_req->seg[i_seg].offset;
 570                         seg = (struct scsiif_request_segment *)end_seg;
 571                         end_seg += ring_req->seg[i_seg].length;
 572                 }
 573                 if (sg->offset >= PAGE_SIZE ||
 574                     sg->length > PAGE_SIZE ||
 575                     sg->offset + sg->length > PAGE_SIZE)
 576                         return -EINVAL;
 577         }
 578
 579         return 0;
 580 }
 581
 582 static void scsiback_disconnect(struct vscsibk_info *info)
 583 {
 584         wait_event(info->waiting_to_free,
 585                 atomic_read(&info->nr_unreplied_reqs) == 0);
 586
 587         unbind_from_irqhandler(info->irq, info);
 588         info->irq = 0;
 589         xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
 590 }
 591
 592 static void scsiback_device_action(struct vscsibk_pend *pending_req,
 593         enum tcm_tmreq_table act, int tag)
 594 {
 595         int rc, err = FAILED;
 596         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 597         struct se_cmd *se_cmd = &pending_req->se_cmd;
 598         struct scsiback_tmr *tmr;
 599
 600         tmr = kzalloc(sizeof(struct scsiback_tmr), GFP_KERNEL);
 601         if (!tmr)
 602                 goto out;
 603
 604         init_waitqueue_head(&tmr->tmr_wait);
 605
 606         transport_init_se_cmd(se_cmd, tpg->se_tpg.se_tpg_tfo,
 607                 tpg->tpg_nexus->tvn_se_sess, 0, DMA_NONE, TCM_SIMPLE_TAG,
 608                 &pending_req->sense_buffer[0]);
 609
 610         rc = core_tmr_alloc_req(se_cmd, tmr, act, GFP_KERNEL);
 611         if (rc < 0)
 612                 goto out;
 613
 614         se_cmd->se_tmr_req->ref_task_tag = tag;
 615
 616         if (transport_lookup_tmr_lun(se_cmd, pending_req->v2p->lun) < 0)
 617                 goto out;
 618
 619         transport_generic_handle_tmr(se_cmd);
 620         wait_event(tmr->tmr_wait, atomic_read(&tmr->tmr_complete));
 621
 622         err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
 623                 SUCCESS : FAILED;
 624
 625 out:
 626         if (tmr) {
 627                 transport_generic_free_cmd(&pending_req->se_cmd, 1);
 628                 kfree(tmr);
 629         }
 630
 631         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 632
 633         kmem_cache_free(scsiback_cachep, pending_req);
 634 }
 635
 636 /*
 637   Perform virtual to physical translation
 638 */
 639 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
 640                         struct ids_tuple *v)
 641 {
 642         struct v2p_entry *entry;
 643         struct list_head *head = &(info->v2p_entry_lists);
 644         unsigned long flags;
 645
 646         spin_lock_irqsave(&info->v2p_lock, flags);
 647         list_for_each_entry(entry, head, l) {
 648                 if ((entry->v.chn == v->chn) &&
 649                     (entry->v.tgt == v->tgt) &&
 650                     (entry->v.lun == v->lun)) {
 651                         kref_get(&entry->kref);
 652                         goto out;
 653                 }
 654         }
 655         entry = NULL;
 656
 657 out:
 658         spin_unlock_irqrestore(&info->v2p_lock, flags);
 659         return entry;
 660 }
 661
 662 static int prepare_pending_reqs(struct vscsibk_info *info,
 663                                 struct vscsiif_request *ring_req,
 664                                 struct vscsibk_pend *pending_req)
 665 {
 666         struct v2p_entry *v2p;
 667         struct ids_tuple vir;
 668
 669         pending_req->rqid       = ring_req->rqid;
 670         pending_req->info       = info;
 671
 672         vir.chn = ring_req->channel;
 673         vir.tgt = ring_req->id;
 674         vir.lun = ring_req->lun;
 675
 676         v2p = scsiback_do_translation(info, &vir);
 677         if (!v2p) {
 678                 pending_req->v2p = NULL;
 679                 pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
 680                         vir.chn, vir.tgt, vir.lun);
 681                 return -ENODEV;
 682         }
 683         pending_req->v2p = v2p;
 684
 685         /* request range check from frontend */
 686         pending_req->sc_data_direction = ring_req->sc_data_direction;
 687         if ((pending_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
 688                 (pending_req->sc_data_direction != DMA_TO_DEVICE) &&
 689                 (pending_req->sc_data_direction != DMA_FROM_DEVICE) &&
 690                 (pending_req->sc_data_direction != DMA_NONE)) {
 691                 pr_debug("invalid parameter data_dir = %d\n",
 692                         pending_req->sc_data_direction);
 693                 return -EINVAL;
 694         }
 695
 696         pending_req->cmd_len = ring_req->cmd_len;
 697         if (pending_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
 698                 pr_debug("invalid parameter cmd_len = %d\n",
 699                         pending_req->cmd_len);
 700                 return -EINVAL;
 701         }
 702         memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
 703
 704         return 0;
 705 }
 706
 707 static int scsiback_do_cmd_fn(struct vscsibk_info *info)
 708 {
 709         struct vscsiif_back_ring *ring = &info->ring;
 710         struct vscsiif_request ring_req;
 711         struct vscsibk_pend *pending_req;
 712         RING_IDX rc, rp;
 713         int err, more_to_do;
 714         uint32_t result;
 715
 716         rc = ring->req_cons;
 717         rp = ring->sring->req_prod;
 718         rmb();  /* guest system is accessing ring, too */
 719
 720         if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
 721                 rc = ring->rsp_prod_pvt;
 722                 pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 723                            info->domid, rp, rc, rp - rc);
 724                 info->ring_error = 1;
 725                 return 0;
 726         }
 727
 728         while ((rc != rp)) {
 729                 if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
 730                         break;
 731                 pending_req = kmem_cache_alloc(scsiback_cachep, GFP_KERNEL);
 732                 if (!pending_req)
 733                         return 1;
 734
 735                 ring_req = *RING_GET_REQUEST(ring, rc);
 736                 ring->req_cons = ++rc;
 737
 738                 err = prepare_pending_reqs(info, &ring_req, pending_req);
 739                 if (err) {
 740                         switch (err) {
 741                         case -ENODEV:
 742                                 result = DID_NO_CONNECT;
 743                                 break;
 744                         default:
 745                                 result = DRIVER_ERROR;
 746                                 break;
 747                         }
 748                         scsiback_do_resp_with_sense(NULL, result << 24, 0,
 749                                                     pending_req);
 750                         kmem_cache_free(scsiback_cachep, pending_req);
 751                         return 1;
 752                 }
 753
 754                 switch (ring_req.act) {
 755                 case VSCSIIF_ACT_SCSI_CDB:
 756                         if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
 757                                 scsiback_fast_flush_area(pending_req);
 758                                 scsiback_do_resp_with_sense(NULL,
 759                                         DRIVER_ERROR << 24, 0, pending_req);
 760                                 kmem_cache_free(scsiback_cachep, pending_req);
 761                         } else {
 762                                 scsiback_cmd_exec(pending_req);
 763                         }
 764                         break;
 765                 case VSCSIIF_ACT_SCSI_ABORT:
 766                         scsiback_device_action(pending_req, TMR_ABORT_TASK,
 767                                 ring_req.ref_rqid);
 768                         break;
 769                 case VSCSIIF_ACT_SCSI_RESET:
 770                         scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
 771                         break;
 772                 default:
 773                         pr_err_ratelimited("invalid request\n");
 774                         scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24,
 775                                                     0, pending_req);
 776                         kmem_cache_free(scsiback_cachep, pending_req);
 777                         break;
 778                 }
 779
 780                 /* Yield point for this unbounded loop. */
 781                 cond_resched();
 782         }
 783
 784         RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
 785         return more_to_do;
 786 }
 787
 788 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
 789 {
 790         struct vscsibk_info *info = dev_id;
 791
 792         if (info->ring_error)
 793                 return IRQ_HANDLED;
 794
 795         while (scsiback_do_cmd_fn(info))
 796                 cond_resched();
 797
 798         return IRQ_HANDLED;
 799 }
 800
 801 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 802                         evtchn_port_t evtchn)
 803 {
 804         void *area;
 805         struct vscsiif_sring *sring;
 806         int err;
 807
 808         if (info->irq)
 809                 return -1;
 810
 811         err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 812         if (err)
 813                 return err;
 814
 815         sring = (struct vscsiif_sring *)area;
 816         BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 817
 818         err = bind_interdomain_evtchn_to_irq(info->domid, evtchn);
 819         if (err < 0)
 820                 goto unmap_page;
 821
 822         info->irq = err;
 823
 824         err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
 825                                    IRQF_ONESHOT, "vscsiif-backend", info);
 826         if (err)
 827                 goto free_irq;
 828
 829         return 0;
 830
 831 free_irq:
 832         unbind_from_irqhandler(info->irq, info);
 833         info->irq = 0;
 834 unmap_page:
 835         xenbus_unmap_ring_vfree(info->dev, area);
 836
 837         return err;
 838 }
 839
 840 static int scsiback_map(struct vscsibk_info *info)
 841 {
 842         struct xenbus_device *dev = info->dev;
 843         unsigned int ring_ref, evtchn;
 844         int err;
 845
 846         err = xenbus_gather(XBT_NIL, dev->otherend,
 847                         "ring-ref", "%u", &ring_ref,
 848                         "event-channel", "%u", &evtchn, NULL);
 849         if (err) {
 850                 xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
 851                 return err;
 852         }
 853
 854         return scsiback_init_sring(info, ring_ref, evtchn);
 855 }
 856
 857 /*
 858   Add a new translation entry
 859 */
 860 static int scsiback_add_translation_entry(struct vscsibk_info *info,
 861                                           char *phy, struct ids_tuple *v)
 862 {
 863         int err = 0;
 864         struct v2p_entry *entry;
 865         struct v2p_entry *new;
 866         struct list_head *head = &(info->v2p_entry_lists);
 867         unsigned long flags;
 868         char *lunp;
 869         unsigned int lun;
 870         struct scsiback_tpg *tpg_entry, *tpg = NULL;
 871         char *error = "doesn't exist";
 872
 873         lunp = strrchr(phy, ':');
 874         if (!lunp) {
 875                 pr_err("illegal format of physical device %s\n", phy);
 876                 return -EINVAL;
 877         }
 878         *lunp = 0;
 879         lunp++;
 880         if (kstrtouint(lunp, 10, &lun) || lun >= TRANSPORT_MAX_LUNS_PER_TPG) {
 881                 pr_err("lun number not valid: %s\n", lunp);
 882                 return -EINVAL;
 883         }
 884
 885         mutex_lock(&scsiback_mutex);
 886         list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
 887                 if (!strcmp(phy, tpg_entry->tport->tport_name) ||
 888                     !strcmp(phy, tpg_entry->param_alias)) {
 889                         spin_lock(&tpg_entry->se_tpg.tpg_lun_lock);
 890                         if (tpg_entry->se_tpg.tpg_lun_list[lun]->lun_status ==
 891                             TRANSPORT_LUN_STATUS_ACTIVE) {
 892                                 if (!tpg_entry->tpg_nexus)
 893                                         error = "nexus undefined";
 894                                 else
 895                                         tpg = tpg_entry;
 896                         }
 897                         spin_unlock(&tpg_entry->se_tpg.tpg_lun_lock);
 898                         break;
 899                 }
 900         }
 901         if (tpg) {
 902                 mutex_lock(&tpg->tv_tpg_mutex);
 903                 tpg->tv_tpg_fe_count++;
 904                 mutex_unlock(&tpg->tv_tpg_mutex);
 905         }
 906         mutex_unlock(&scsiback_mutex);
 907
 908         if (!tpg) {
 909                 pr_err("%s:%d %s\n", phy, lun, error);
 910                 return -ENODEV;
 911         }
 912
 913         new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
 914         if (new == NULL) {
 915                 err = -ENOMEM;
 916                 goto out_free;
 917         }
 918
 919         spin_lock_irqsave(&info->v2p_lock, flags);
 920
 921         /* Check double assignment to identical virtual ID */
 922         list_for_each_entry(entry, head, l) {
 923                 if ((entry->v.chn == v->chn) &&
 924                     (entry->v.tgt == v->tgt) &&
 925                     (entry->v.lun == v->lun)) {
 926                         pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 927                         err = -EEXIST;
 928                         goto out;
 929                 }
 930
 931         }
 932
 933         /* Create a new translation entry and add to the list */
 934         kref_init(&new->kref);
 935         new->v = *v;
 936         new->tpg = tpg;
 937         new->lun = lun;
 938         list_add_tail(&new->l, head);
 939
 940 out:
 941         spin_unlock_irqrestore(&info->v2p_lock, flags);
 942
 943 out_free:
 944         mutex_lock(&tpg->tv_tpg_mutex);
 945         tpg->tv_tpg_fe_count--;
 946         mutex_unlock(&tpg->tv_tpg_mutex);
 947
 948         if (err)
 949                 kfree(new);
 950
 951         return err;
 952 }
 953
 954 static void __scsiback_del_translation_entry(struct v2p_entry *entry)
 955 {
 956         list_del(&entry->l);
 957         kref_put(&entry->kref, scsiback_free_translation_entry);
 958 }
 959
 960 /*
 961   Delete the translation entry specfied
 962 */
 963 static int scsiback_del_translation_entry(struct vscsibk_info *info,
 964                                           struct ids_tuple *v)
 965 {
 966         struct v2p_entry *entry;
 967         struct list_head *head = &(info->v2p_entry_lists);
 968         unsigned long flags;
 969
 970         spin_lock_irqsave(&info->v2p_lock, flags);
 971         /* Find out the translation entry specified */
 972         list_for_each_entry(entry, head, l) {
 973                 if ((entry->v.chn == v->chn) &&
 974                     (entry->v.tgt == v->tgt) &&
 975                     (entry->v.lun == v->lun)) {
 976                         goto found;
 977                 }
 978         }
 979
 980         spin_unlock_irqrestore(&info->v2p_lock, flags);
 981         return 1;
 982
 983 found:
 984         /* Delete the translation entry specfied */
 985         __scsiback_del_translation_entry(entry);
 986
 987         spin_unlock_irqrestore(&info->v2p_lock, flags);
 988         return 0;
 989 }
 990
 991 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
 992                                 char *phy, struct ids_tuple *vir, int try)
 993 {
 994         if (!scsiback_add_translation_entry(info, phy, vir)) {
 995                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
 996                                   "%d", XenbusStateInitialised)) {
 997                         pr_err("xenbus_printf error %s\n", state);
 998                         scsiback_del_translation_entry(info, vir);
 999                 }
1000         } else if (!try) {
1001                 xenbus_printf(XBT_NIL, info->dev->nodename, state,
1002                               "%d", XenbusStateClosed);
1003         }
1004 }
1005
1006 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1007                                 struct ids_tuple *vir)
1008 {
1009         if (!scsiback_del_translation_entry(info, vir)) {
1010                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1011                                   "%d", XenbusStateClosed))
1012                         pr_err("xenbus_printf error %s\n", state);
1013         }
1014 }
1015
1016 #define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1017 #define VSCSIBACK_OP_UPDATEDEV_STATE    2
1018
1019 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1020                                      char *ent)
1021 {
1022         int err;
1023         struct ids_tuple vir;
1024         char *val;
1025         int device_state;
1026         char phy[VSCSI_NAMELEN];
1027         char str[64];
1028         char state[64];
1029         struct xenbus_device *dev = info->dev;
1030
1031         /* read status */
1032         snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1033         err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1034         if (XENBUS_EXIST_ERR(err))
1035                 return;
1036
1037         /* physical SCSI device */
1038         snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1039         val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1040         if (IS_ERR(val)) {
1041                 xenbus_printf(XBT_NIL, dev->nodename, state,
1042                               "%d", XenbusStateClosed);
1043                 return;
1044         }
1045         strlcpy(phy, val, VSCSI_NAMELEN);
1046         kfree(val);
1047
1048         /* virtual SCSI device */
1049         snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1050         err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1051                            &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1052         if (XENBUS_EXIST_ERR(err)) {
1053                 xenbus_printf(XBT_NIL, dev->nodename, state,
1054                               "%d", XenbusStateClosed);
1055                 return;
1056         }
1057
1058         switch (op) {
1059         case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1060                 switch (device_state) {
1061                 case XenbusStateInitialising:
1062                         scsiback_do_add_lun(info, state, phy, &vir, 0);
1063                         break;
1064                 case XenbusStateConnected:
1065                         scsiback_do_add_lun(info, state, phy, &vir, 1);
1066                         break;
1067                 case XenbusStateClosing:
1068                         scsiback_do_del_lun(info, state, &vir);
1069                         break;
1070                 default:
1071                         break;
1072                 }
1073                 break;
1074
1075         case VSCSIBACK_OP_UPDATEDEV_STATE:
1076                 if (device_state == XenbusStateInitialised) {
1077                         /* modify vscsi-devs/dev-x/state */
1078                         if (xenbus_printf(XBT_NIL, dev->nodename, state,
1079                                           "%d", XenbusStateConnected)) {
1080                                 pr_err("xenbus_printf error %s\n", str);
1081                                 scsiback_del_translation_entry(info, &vir);
1082                                 xenbus_printf(XBT_NIL, dev->nodename, state,
1083                                               "%d", XenbusStateClosed);
1084                         }
1085                 }
1086                 break;
1087         /* When it is necessary, processing is added here. */
1088         default:
1089                 break;
1090         }
1091 }
1092
1093 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1094 {
1095         int i;
1096         char **dir;
1097         unsigned int ndir = 0;
1098
1099         dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1100                                &ndir);
1101         if (IS_ERR(dir))
1102                 return;
1103
1104         for (i = 0; i < ndir; i++)
1105                 scsiback_do_1lun_hotplug(info, op, dir[i]);
1106
1107         kfree(dir);
1108 }
1109
1110 static void scsiback_frontend_changed(struct xenbus_device *dev,
1111                                         enum xenbus_state frontend_state)
1112 {
1113         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1114
1115         switch (frontend_state) {
1116         case XenbusStateInitialising:
1117                 break;
1118
1119         case XenbusStateInitialised:
1120                 if (scsiback_map(info))
1121                         break;
1122
1123                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1124                 xenbus_switch_state(dev, XenbusStateConnected);
1125                 break;
1126
1127         case XenbusStateConnected:
1128                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1129
1130                 if (dev->state == XenbusStateConnected)
1131                         break;
1132
1133                 xenbus_switch_state(dev, XenbusStateConnected);
1134                 break;
1135
1136         case XenbusStateClosing:
1137                 if (info->irq)
1138                         scsiback_disconnect(info);
1139
1140                 xenbus_switch_state(dev, XenbusStateClosing);
1141                 break;
1142
1143         case XenbusStateClosed:
1144                 xenbus_switch_state(dev, XenbusStateClosed);
1145                 if (xenbus_dev_is_online(dev))
1146                         break;
1147                 /* fall through if not online */
1148         case XenbusStateUnknown:
1149                 device_unregister(&dev->dev);
1150                 break;
1151
1152         case XenbusStateReconfiguring:
1153                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1154                 xenbus_switch_state(dev, XenbusStateReconfigured);
1155
1156                 break;
1157
1158         default:
1159                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1160                                         frontend_state);
1161                 break;
1162         }
1163 }
1164
1165 /*
1166   Release the translation entry specfied
1167 */
1168 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1169 {
1170         struct v2p_entry *entry, *tmp;
1171         struct list_head *head = &(info->v2p_entry_lists);
1172         unsigned long flags;
1173
1174         spin_lock_irqsave(&info->v2p_lock, flags);
1175
1176         list_for_each_entry_safe(entry, tmp, head, l)
1177                 __scsiback_del_translation_entry(entry);
1178
1179         spin_unlock_irqrestore(&info->v2p_lock, flags);
1180 }
1181
1182 static int scsiback_remove(struct xenbus_device *dev)
1183 {
1184         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1185
1186         if (info->irq)
1187                 scsiback_disconnect(info);
1188
1189         scsiback_release_translation_entry(info);
1190
1191         dev_set_drvdata(&dev->dev, NULL);
1192
1193         return 0;
1194 }
1195
1196 static int scsiback_probe(struct xenbus_device *dev,
1197                            const struct xenbus_device_id *id)
1198 {
1199         int err;
1200
1201         struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1202                                             GFP_KERNEL);
1203
1204         pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1205
1206         if (!info) {
1207                 xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1208                 return -ENOMEM;
1209         }
1210         info->dev = dev;
1211         dev_set_drvdata(&dev->dev, info);
1212
1213         info->domid = dev->otherend_id;
1214         spin_lock_init(&info->ring_lock);
1215         info->ring_error = 0;
1216         atomic_set(&info->nr_unreplied_reqs, 0);
1217         init_waitqueue_head(&info->waiting_to_free);
1218         info->dev = dev;
1219         info->irq = 0;
1220         INIT_LIST_HEAD(&info->v2p_entry_lists);
1221         spin_lock_init(&info->v2p_lock);
1222
1223         err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1224                             SG_ALL);
1225         if (err)
1226                 xenbus_dev_error(dev, err, "writing feature-sg-grant");
1227
1228         err = xenbus_switch_state(dev, XenbusStateInitWait);
1229         if (err)
1230                 goto fail;
1231
1232         return 0;
1233
1234 fail:
1235         pr_warn("%s failed\n", __func__);
1236         scsiback_remove(dev);
1237
1238         return err;
1239 }
1240
1241 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1242 {
1243         switch (tport->tport_proto_id) {
1244         case SCSI_PROTOCOL_SAS:
1245                 return "SAS";
1246         case SCSI_PROTOCOL_FCP:
1247                 return "FCP";
1248         case SCSI_PROTOCOL_ISCSI:
1249                 return "iSCSI";
1250         default:
1251                 break;
1252         }
1253
1254         return "Unknown";
1255 }
1256
1257 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1258 {
1259         struct scsiback_tpg *tpg = container_of(se_tpg,
1260                                 struct scsiback_tpg, se_tpg);
1261         struct scsiback_tport *tport = tpg->tport;
1262
1263         return &tport->tport_name[0];
1264 }
1265
1266 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1267 {
1268         struct scsiback_tpg *tpg = container_of(se_tpg,
1269                                 struct scsiback_tpg, se_tpg);
1270         return tpg->tport_tpgt;
1271 }
1272
1273 static struct se_wwn *
1274 scsiback_make_tport(struct target_fabric_configfs *tf,
1275                      struct config_group *group,
1276                      const char *name)
1277 {
1278         struct scsiback_tport *tport;
1279         char *ptr;
1280         u64 wwpn = 0;
1281         int off = 0;
1282
1283         tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1284         if (!tport)
1285                 return ERR_PTR(-ENOMEM);
1286
1287         tport->tport_wwpn = wwpn;
1288         /*
1289          * Determine the emulated Protocol Identifier and Target Port Name
1290          * based on the incoming configfs directory name.
1291          */
1292         ptr = strstr(name, "naa.");
1293         if (ptr) {
1294                 tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1295                 goto check_len;
1296         }
1297         ptr = strstr(name, "fc.");
1298         if (ptr) {
1299                 tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1300                 off = 3; /* Skip over "fc." */
1301                 goto check_len;
1302         }
1303         ptr = strstr(name, "iqn.");
1304         if (ptr) {
1305                 tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1306                 goto check_len;
1307         }
1308
1309         pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1310         kfree(tport);
1311         return ERR_PTR(-EINVAL);
1312
1313 check_len:
1314         if (strlen(name) >= VSCSI_NAMELEN) {
1315                 pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1316                         scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1317                 kfree(tport);
1318                 return ERR_PTR(-EINVAL);
1319         }
1320         snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1321
1322         pr_debug("Allocated emulated Target %s Address: %s\n",
1323                  scsiback_dump_proto_id(tport), name);
1324
1325         return &tport->tport_wwn;
1326 }
1327
1328 static void scsiback_drop_tport(struct se_wwn *wwn)
1329 {
1330         struct scsiback_tport *tport = container_of(wwn,
1331                                 struct scsiback_tport, tport_wwn);
1332
1333         pr_debug("Deallocating emulated Target %s Address: %s\n",
1334                  scsiback_dump_proto_id(tport), tport->tport_name);
1335
1336         kfree(tport);
1337 }
1338
1339 static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1340 {
1341         return 1;
1342 }
1343
1344 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1345 {
1346         /*
1347          * Do not release struct se_cmd's containing a valid TMR pointer.
1348          * These will be released directly in scsiback_device_action()
1349          * with transport_generic_free_cmd().
1350          */
1351         if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
1352                 return 0;
1353
1354         transport_generic_free_cmd(se_cmd, 0);
1355         return 1;
1356 }
1357
1358 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1359 {
1360         struct vscsibk_pend *pending_req = container_of(se_cmd,
1361                                 struct vscsibk_pend, se_cmd);
1362
1363         kmem_cache_free(scsiback_cachep, pending_req);
1364 }
1365
1366 static int scsiback_shutdown_session(struct se_session *se_sess)
1367 {
1368         return 0;
1369 }
1370
1371 static void scsiback_close_session(struct se_session *se_sess)
1372 {
1373 }
1374
1375 static u32 scsiback_sess_get_index(struct se_session *se_sess)
1376 {
1377         return 0;
1378 }
1379
1380 static int scsiback_write_pending(struct se_cmd *se_cmd)
1381 {
1382         /* Go ahead and process the write immediately */
1383         target_execute_cmd(se_cmd);
1384
1385         return 0;
1386 }
1387
1388 static int scsiback_write_pending_status(struct se_cmd *se_cmd)
1389 {
1390         return 0;
1391 }
1392
1393 static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1394 {
1395 }
1396
1397 static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1398 {
1399         return 0;
1400 }
1401
1402 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1403 {
1404         struct vscsibk_pend *pending_req = container_of(se_cmd,
1405                                 struct vscsibk_pend, se_cmd);
1406
1407         pending_req->result = SAM_STAT_GOOD;
1408         scsiback_cmd_done(pending_req);
1409         return 0;
1410 }
1411
1412 static int scsiback_queue_status(struct se_cmd *se_cmd)
1413 {
1414         struct vscsibk_pend *pending_req = container_of(se_cmd,
1415                                 struct vscsibk_pend, se_cmd);
1416
1417         if (se_cmd->sense_buffer &&
1418             ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1419              (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1420                 pending_req->result = (DRIVER_SENSE << 24) |
1421                                       SAM_STAT_CHECK_CONDITION;
1422         else
1423                 pending_req->result = se_cmd->scsi_status;
1424
1425         scsiback_cmd_done(pending_req);
1426         return 0;
1427 }
1428
1429 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1430 {
1431         struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
1432         struct scsiback_tmr *tmr = se_tmr->fabric_tmr_ptr;
1433
1434         atomic_set(&tmr->tmr_complete, 1);
1435         wake_up(&tmr->tmr_wait);
1436 }
1437
1438 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1439 {
1440 }
1441
1442 static ssize_t scsiback_tpg_param_show_alias(struct se_portal_group *se_tpg,
1443                                              char *page)
1444 {
1445         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1446                                                 se_tpg);
1447         ssize_t rb;
1448
1449         mutex_lock(&tpg->tv_tpg_mutex);
1450         rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1451         mutex_unlock(&tpg->tv_tpg_mutex);
1452
1453         return rb;
1454 }
1455
1456 static ssize_t scsiback_tpg_param_store_alias(struct se_portal_group *se_tpg,
1457                                               const char *page, size_t count)
1458 {
1459         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1460                                                 se_tpg);
1461         int len;
1462
1463         if (strlen(page) >= VSCSI_NAMELEN) {
1464                 pr_err("param alias: %s, exceeds max: %d\n", page,
1465                         VSCSI_NAMELEN);
1466                 return -EINVAL;
1467         }
1468
1469         mutex_lock(&tpg->tv_tpg_mutex);
1470         len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1471         if (tpg->param_alias[len - 1] == '\n')
1472                 tpg->param_alias[len - 1] = '\0';
1473         mutex_unlock(&tpg->tv_tpg_mutex);
1474
1475         return count;
1476 }
1477
1478 TF_TPG_PARAM_ATTR(scsiback, alias, S_IRUGO | S_IWUSR);
1479
1480 static struct configfs_attribute *scsiback_param_attrs[] = {
1481         &scsiback_tpg_param_alias.attr,
1482         NULL,
1483 };
1484
1485 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1486                                 const char *name)
1487 {
1488         struct se_portal_group *se_tpg;
1489         struct se_session *se_sess;
1490         struct scsiback_nexus *tv_nexus;
1491
1492         mutex_lock(&tpg->tv_tpg_mutex);
1493         if (tpg->tpg_nexus) {
1494                 mutex_unlock(&tpg->tv_tpg_mutex);
1495                 pr_debug("tpg->tpg_nexus already exists\n");
1496                 return -EEXIST;
1497         }
1498         se_tpg = &tpg->se_tpg;
1499
1500         tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1501         if (!tv_nexus) {
1502                 mutex_unlock(&tpg->tv_tpg_mutex);
1503                 return -ENOMEM;
1504         }
1505         /*
1506          * Initialize the struct se_session pointer
1507          */
1508         tv_nexus->tvn_se_sess = transport_init_session(TARGET_PROT_NORMAL);
1509         if (IS_ERR(tv_nexus->tvn_se_sess)) {
1510                 mutex_unlock(&tpg->tv_tpg_mutex);
1511                 kfree(tv_nexus);
1512                 return -ENOMEM;
1513         }
1514         se_sess = tv_nexus->tvn_se_sess;
1515         /*
1516          * Since we are running in 'demo mode' this call with generate a
1517          * struct se_node_acl for the scsiback struct se_portal_group with
1518          * the SCSI Initiator port name of the passed configfs group 'name'.
1519          */
1520         tv_nexus->tvn_se_sess->se_node_acl = core_tpg_check_initiator_node_acl(
1521                                 se_tpg, (unsigned char *)name);
1522         if (!tv_nexus->tvn_se_sess->se_node_acl) {
1523                 mutex_unlock(&tpg->tv_tpg_mutex);
1524                 pr_debug("core_tpg_check_initiator_node_acl() failed for %s\n",
1525                          name);
1526                 goto out;
1527         }
1528         /* Now register the TCM pvscsi virtual I_T Nexus as active. */
1529         transport_register_session(se_tpg, tv_nexus->tvn_se_sess->se_node_acl,
1530                         tv_nexus->tvn_se_sess, tv_nexus);
1531         tpg->tpg_nexus = tv_nexus;
1532
1533         mutex_unlock(&tpg->tv_tpg_mutex);
1534         return 0;
1535
1536 out:
1537         transport_free_session(se_sess);
1538         kfree(tv_nexus);
1539         return -ENOMEM;
1540 }
1541
1542 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1543 {
1544         struct se_session *se_sess;
1545         struct scsiback_nexus *tv_nexus;
1546
1547         mutex_lock(&tpg->tv_tpg_mutex);
1548         tv_nexus = tpg->tpg_nexus;
1549         if (!tv_nexus) {
1550                 mutex_unlock(&tpg->tv_tpg_mutex);
1551                 return -ENODEV;
1552         }
1553
1554         se_sess = tv_nexus->tvn_se_sess;
1555         if (!se_sess) {
1556                 mutex_unlock(&tpg->tv_tpg_mutex);
1557                 return -ENODEV;
1558         }
1559
1560         if (tpg->tv_tpg_port_count != 0) {
1561                 mutex_unlock(&tpg->tv_tpg_mutex);
1562                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1563                         tpg->tv_tpg_port_count);
1564                 return -EBUSY;
1565         }
1566
1567         if (tpg->tv_tpg_fe_count != 0) {
1568                 mutex_unlock(&tpg->tv_tpg_mutex);
1569                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1570                         tpg->tv_tpg_fe_count);
1571                 return -EBUSY;
1572         }
1573
1574         pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1575                 scsiback_dump_proto_id(tpg->tport),
1576                 tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1577
1578         /*
1579          * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1580          */
1581         transport_deregister_session(tv_nexus->tvn_se_sess);
1582         tpg->tpg_nexus = NULL;
1583         mutex_unlock(&tpg->tv_tpg_mutex);
1584
1585         kfree(tv_nexus);
1586         return 0;
1587 }
1588
1589 static ssize_t scsiback_tpg_show_nexus(struct se_portal_group *se_tpg,
1590                                         char *page)
1591 {
1592         struct scsiback_tpg *tpg = container_of(se_tpg,
1593                                 struct scsiback_tpg, se_tpg);
1594         struct scsiback_nexus *tv_nexus;
1595         ssize_t ret;
1596
1597         mutex_lock(&tpg->tv_tpg_mutex);
1598         tv_nexus = tpg->tpg_nexus;
1599         if (!tv_nexus) {
1600                 mutex_unlock(&tpg->tv_tpg_mutex);
1601                 return -ENODEV;
1602         }
1603         ret = snprintf(page, PAGE_SIZE, "%s\n",
1604                         tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1605         mutex_unlock(&tpg->tv_tpg_mutex);
1606
1607         return ret;
1608 }
1609
1610 static ssize_t scsiback_tpg_store_nexus(struct se_portal_group *se_tpg,
1611                                          const char *page,
1612                                          size_t count)
1613 {
1614         struct scsiback_tpg *tpg = container_of(se_tpg,
1615                                 struct scsiback_tpg, se_tpg);
1616         struct scsiback_tport *tport_wwn = tpg->tport;
1617         unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1618         int ret;
1619         /*
1620          * Shutdown the active I_T nexus if 'NULL' is passed.
1621          */
1622         if (!strncmp(page, "NULL", 4)) {
1623                 ret = scsiback_drop_nexus(tpg);
1624                 return (!ret) ? count : ret;
1625         }
1626         /*
1627          * Otherwise make sure the passed virtual Initiator port WWN matches
1628          * the fabric protocol_id set in scsiback_make_tport(), and call
1629          * scsiback_make_nexus().
1630          */
1631         if (strlen(page) >= VSCSI_NAMELEN) {
1632                 pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1633                         page, VSCSI_NAMELEN);
1634                 return -EINVAL;
1635         }
1636         snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1637
1638         ptr = strstr(i_port, "naa.");
1639         if (ptr) {
1640                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1641                         pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1642                                 i_port, scsiback_dump_proto_id(tport_wwn));
1643                         return -EINVAL;
1644                 }
1645                 port_ptr = &i_port[0];
1646                 goto check_newline;
1647         }
1648         ptr = strstr(i_port, "fc.");
1649         if (ptr) {
1650                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1651                         pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1652                                 i_port, scsiback_dump_proto_id(tport_wwn));
1653                         return -EINVAL;
1654                 }
1655                 port_ptr = &i_port[3]; /* Skip over "fc." */
1656                 goto check_newline;
1657         }
1658         ptr = strstr(i_port, "iqn.");
1659         if (ptr) {
1660                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1661                         pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1662                                 i_port, scsiback_dump_proto_id(tport_wwn));
1663                         return -EINVAL;
1664                 }
1665                 port_ptr = &i_port[0];
1666                 goto check_newline;
1667         }
1668         pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1669                 i_port);
1670         return -EINVAL;
1671         /*
1672          * Clear any trailing newline for the NAA WWN
1673          */
1674 check_newline:
1675         if (i_port[strlen(i_port) - 1] == '\n')
1676                 i_port[strlen(i_port) - 1] = '\0';
1677
1678         ret = scsiback_make_nexus(tpg, port_ptr);
1679         if (ret < 0)
1680                 return ret;
1681
1682         return count;
1683 }
1684
1685 TF_TPG_BASE_ATTR(scsiback, nexus, S_IRUGO | S_IWUSR);
1686
1687 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1688         &scsiback_tpg_nexus.attr,
1689         NULL,
1690 };
1691
1692 static ssize_t
1693 scsiback_wwn_show_attr_version(struct target_fabric_configfs *tf,
1694                                 char *page)
1695 {
1696         return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1697                 UTS_RELEASE"\n",
1698                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1699 }
1700
1701 TF_WWN_ATTR_RO(scsiback, version);
1702
1703 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1704         &scsiback_wwn_version.attr,
1705         NULL,
1706 };
1707
1708 static char *scsiback_get_fabric_name(void)
1709 {
1710         return "xen-pvscsi";
1711 }
1712
1713 static int scsiback_port_link(struct se_portal_group *se_tpg,
1714                                struct se_lun *lun)
1715 {
1716         struct scsiback_tpg *tpg = container_of(se_tpg,
1717                                 struct scsiback_tpg, se_tpg);
1718
1719         mutex_lock(&tpg->tv_tpg_mutex);
1720         tpg->tv_tpg_port_count++;
1721         mutex_unlock(&tpg->tv_tpg_mutex);
1722
1723         return 0;
1724 }
1725
1726 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1727                                   struct se_lun *lun)
1728 {
1729         struct scsiback_tpg *tpg = container_of(se_tpg,
1730                                 struct scsiback_tpg, se_tpg);
1731
1732         mutex_lock(&tpg->tv_tpg_mutex);
1733         tpg->tv_tpg_port_count--;
1734         mutex_unlock(&tpg->tv_tpg_mutex);
1735 }
1736
1737 static struct se_portal_group *
1738 scsiback_make_tpg(struct se_wwn *wwn,
1739                    struct config_group *group,
1740                    const char *name)
1741 {
1742         struct scsiback_tport *tport = container_of(wwn,
1743                         struct scsiback_tport, tport_wwn);
1744
1745         struct scsiback_tpg *tpg;
1746         u16 tpgt;
1747         int ret;
1748
1749         if (strstr(name, "tpgt_") != name)
1750                 return ERR_PTR(-EINVAL);
1751         ret = kstrtou16(name + 5, 10, &tpgt);
1752         if (ret)
1753                 return ERR_PTR(ret);
1754
1755         tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1756         if (!tpg)
1757                 return ERR_PTR(-ENOMEM);
1758
1759         mutex_init(&tpg->tv_tpg_mutex);
1760         INIT_LIST_HEAD(&tpg->tv_tpg_list);
1761         INIT_LIST_HEAD(&tpg->info_list);
1762         tpg->tport = tport;
1763         tpg->tport_tpgt = tpgt;
1764
1765         ret = core_tpg_register(&scsiback_ops, wwn, &tpg->se_tpg,
1766                                 tport->tport_proto_id);
1767         if (ret < 0) {
1768                 kfree(tpg);
1769                 return NULL;
1770         }
1771         mutex_lock(&scsiback_mutex);
1772         list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1773         mutex_unlock(&scsiback_mutex);
1774
1775         return &tpg->se_tpg;
1776 }
1777
1778 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1779 {
1780         struct scsiback_tpg *tpg = container_of(se_tpg,
1781                                 struct scsiback_tpg, se_tpg);
1782
1783         mutex_lock(&scsiback_mutex);
1784         list_del(&tpg->tv_tpg_list);
1785         mutex_unlock(&scsiback_mutex);
1786         /*
1787          * Release the virtual I_T Nexus for this xen-pvscsi TPG
1788          */
1789         scsiback_drop_nexus(tpg);
1790         /*
1791          * Deregister the se_tpg from TCM.
1792          */
1793         core_tpg_deregister(se_tpg);
1794         kfree(tpg);
1795 }
1796
1797 static int scsiback_check_true(struct se_portal_group *se_tpg)
1798 {
1799         return 1;
1800 }
1801
1802 static int scsiback_check_false(struct se_portal_group *se_tpg)
1803 {
1804         return 0;
1805 }
1806
1807 static const struct target_core_fabric_ops scsiback_ops = {
1808         .module                         = THIS_MODULE,
1809         .name                           = "xen-pvscsi",
1810         .get_fabric_name                = scsiback_get_fabric_name,
1811         .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1812         .tpg_get_tag                    = scsiback_get_tag,
1813         .tpg_check_demo_mode            = scsiback_check_true,
1814         .tpg_check_demo_mode_cache      = scsiback_check_true,
1815         .tpg_check_demo_mode_write_protect = scsiback_check_false,
1816         .tpg_check_prod_mode_write_protect = scsiback_check_false,
1817         .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1818         .check_stop_free                = scsiback_check_stop_free,
1819         .release_cmd                    = scsiback_release_cmd,
1820         .shutdown_session               = scsiback_shutdown_session,
1821         .close_session                  = scsiback_close_session,
1822         .sess_get_index                 = scsiback_sess_get_index,
1823         .sess_get_initiator_sid         = NULL,
1824         .write_pending                  = scsiback_write_pending,
1825         .write_pending_status           = scsiback_write_pending_status,
1826         .set_default_node_attributes    = scsiback_set_default_node_attrs,
1827         .get_cmd_state                  = scsiback_get_cmd_state,
1828         .queue_data_in                  = scsiback_queue_data_in,
1829         .queue_status                   = scsiback_queue_status,
1830         .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1831         .aborted_task                   = scsiback_aborted_task,
1832         /*
1833          * Setup callers for generic logic in target_core_fabric_configfs.c
1834          */
1835         .fabric_make_wwn                = scsiback_make_tport,
1836         .fabric_drop_wwn                = scsiback_drop_tport,
1837         .fabric_make_tpg                = scsiback_make_tpg,
1838         .fabric_drop_tpg                = scsiback_drop_tpg,
1839         .fabric_post_link               = scsiback_port_link,
1840         .fabric_pre_unlink              = scsiback_port_unlink,
1841
1842         .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1843         .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1844         .tfc_tpg_param_attrs            = scsiback_param_attrs,
1845 };
1846
1847 static const struct xenbus_device_id scsiback_ids[] = {
1848         { "vscsi" },
1849         { "" }
1850 };
1851
1852 static struct xenbus_driver scsiback_driver = {
1853         .ids                    = scsiback_ids,
1854         .probe                  = scsiback_probe,
1855         .remove                 = scsiback_remove,
1856         .otherend_changed       = scsiback_frontend_changed
1857 };
1858
1859 static void scsiback_init_pend(void *p)
1860 {
1861         struct vscsibk_pend *pend = p;
1862         int i;
1863
1864         memset(pend, 0, sizeof(*pend));
1865         for (i = 0; i < VSCSI_MAX_GRANTS; i++)
1866                 pend->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
1867 }
1868
1869 static int __init scsiback_init(void)
1870 {
1871         int ret;
1872
1873         if (!xen_domain())
1874                 return -ENODEV;
1875
1876         pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1877                  VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1878
1879         scsiback_cachep = kmem_cache_create("vscsiif_cache",
1880                 sizeof(struct vscsibk_pend), 0, 0, scsiback_init_pend);
1881         if (!scsiback_cachep)
1882                 return -ENOMEM;
1883
1884         ret = xenbus_register_backend(&scsiback_driver);
1885         if (ret)
1886                 goto out_cache_destroy;
1887
1888         ret = target_register_template(&scsiback_ops);
1889         if (ret)
1890                 goto out_unregister_xenbus;
1891
1892         return 0;
1893
1894 out_unregister_xenbus:
1895         xenbus_unregister_driver(&scsiback_driver);
1896 out_cache_destroy:
1897         kmem_cache_destroy(scsiback_cachep);
1898         pr_err("%s: error %d\n", __func__, ret);
1899         return ret;
1900 }
1901
1902 static void __exit scsiback_exit(void)
1903 {
1904         struct page *page;
1905
1906         while (free_pages_num) {
1907                 if (get_free_page(&page))
1908                         BUG();
1909                 gnttab_free_pages(1, &page);
1910         }
1911         target_unregister_template(&scsiback_ops);
1912         xenbus_unregister_driver(&scsiback_driver);
1913         kmem_cache_destroy(scsiback_cachep);
1914 }
1915
1916 module_init(scsiback_init);
1917 module_exit(scsiback_exit);
1918
1919 MODULE_DESCRIPTION("Xen SCSI backend driver");
1920 MODULE_LICENSE("Dual BSD/GPL");
1921 MODULE_ALIAS("xen-backend:vscsi");
1922 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");