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