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
  95         spinlock_t ring_lock;
  96         atomic_t nr_unreplied_reqs;
  97
  98         spinlock_t v2p_lock;
  99         struct list_head v2p_entry_lists;
 100
 101         wait_queue_head_t waiting_to_free;
 102 };
 103
 104 /* theoretical maximum of grants for one request */
 105 #define VSCSI_MAX_GRANTS        (SG_ALL + VSCSIIF_SG_TABLESIZE)
 106
 107 /*
 108  * VSCSI_GRANT_BATCH is the maximum number of grants to be processed in one
 109  * call to map/unmap grants. Don't choose it too large, as there are arrays
 110  * with VSCSI_GRANT_BATCH elements allocated on the stack.
 111  */
 112 #define VSCSI_GRANT_BATCH       16
 113
 114 struct vscsibk_pend {
 115         uint16_t rqid;
 116
 117         uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE];
 118         uint8_t cmd_len;
 119
 120         uint8_t sc_data_direction;
 121         uint16_t n_sg;          /* real length of SG list */
 122         uint16_t n_grants;      /* SG pages and potentially SG list */
 123         uint32_t data_len;
 124         uint32_t result;
 125
 126         struct vscsibk_info *info;
 127         struct v2p_entry *v2p;
 128         struct scatterlist *sgl;
 129
 130         uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];
 131
 132         grant_handle_t grant_handles[VSCSI_MAX_GRANTS];
 133         struct page *pages[VSCSI_MAX_GRANTS];
 134
 135         struct se_cmd se_cmd;
 136 };
 137
 138 struct scsiback_tmr {
 139         atomic_t tmr_complete;
 140         wait_queue_head_t tmr_wait;
 141 };
 142
 143 struct scsiback_nexus {
 144         /* Pointer to TCM session for I_T Nexus */
 145         struct se_session *tvn_se_sess;
 146 };
 147
 148 struct scsiback_tport {
 149         /* SCSI protocol the tport is providing */
 150         u8 tport_proto_id;
 151         /* Binary World Wide unique Port Name for pvscsi Target port */
 152         u64 tport_wwpn;
 153         /* ASCII formatted WWPN for pvscsi Target port */
 154         char tport_name[VSCSI_NAMELEN];
 155         /* Returned by scsiback_make_tport() */
 156         struct se_wwn tport_wwn;
 157 };
 158
 159 struct scsiback_tpg {
 160         /* scsiback port target portal group tag for TCM */
 161         u16 tport_tpgt;
 162         /* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
 163         int tv_tpg_port_count;
 164         /* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
 165         int tv_tpg_fe_count;
 166         /* list for scsiback_list */
 167         struct list_head tv_tpg_list;
 168         /* Used to protect access for tpg_nexus */
 169         struct mutex tv_tpg_mutex;
 170         /* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
 171         struct scsiback_nexus *tpg_nexus;
 172         /* Pointer back to scsiback_tport */
 173         struct scsiback_tport *tport;
 174         /* Returned by scsiback_make_tpg() */
 175         struct se_portal_group se_tpg;
 176         /* alias used in xenstore */
 177         char param_alias[VSCSI_NAMELEN];
 178         /* list of info structures related to this target portal group */
 179         struct list_head info_list;
 180 };
 181
 182 #define SCSIBACK_INVALID_HANDLE (~0)
 183
 184 static bool log_print_stat;
 185 module_param(log_print_stat, bool, 0644);
 186
 187 static int scsiback_max_buffer_pages = 1024;
 188 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
 189 MODULE_PARM_DESC(max_buffer_pages,
 190 "Maximum number of free pages to keep in backend buffer");
 191
 192 static struct kmem_cache *scsiback_cachep;
 193 static DEFINE_SPINLOCK(free_pages_lock);
 194 static int free_pages_num;
 195 static LIST_HEAD(scsiback_free_pages);
 196
 197 /* Global spinlock to protect scsiback TPG list */
 198 static DEFINE_MUTEX(scsiback_mutex);
 199 static LIST_HEAD(scsiback_list);
 200
 201 static void scsiback_get(struct vscsibk_info *info)
 202 {
 203         atomic_inc(&info->nr_unreplied_reqs);
 204 }
 205
 206 static void scsiback_put(struct vscsibk_info *info)
 207 {
 208         if (atomic_dec_and_test(&info->nr_unreplied_reqs))
 209                 wake_up(&info->waiting_to_free);
 210 }
 211
 212 static void put_free_pages(struct page **page, int num)
 213 {
 214         unsigned long flags;
 215         int i = free_pages_num + num, n = num;
 216
 217         if (num == 0)
 218                 return;
 219         if (i > scsiback_max_buffer_pages) {
 220                 n = min(num, i - scsiback_max_buffer_pages);
 221                 gnttab_free_pages(n, page + num - n);
 222                 n = num - n;
 223         }
 224         spin_lock_irqsave(&free_pages_lock, flags);
 225         for (i = 0; i < n; i++)
 226                 list_add(&page[i]->lru, &scsiback_free_pages);
 227         free_pages_num += n;
 228         spin_unlock_irqrestore(&free_pages_lock, flags);
 229 }
 230
 231 static int get_free_page(struct page **page)
 232 {
 233         unsigned long flags;
 234
 235         spin_lock_irqsave(&free_pages_lock, flags);
 236         if (list_empty(&scsiback_free_pages)) {
 237                 spin_unlock_irqrestore(&free_pages_lock, flags);
 238                 return gnttab_alloc_pages(1, page);
 239         }
 240         page[0] = list_first_entry(&scsiback_free_pages, struct page, lru);
 241         list_del(&page[0]->lru);
 242         free_pages_num--;
 243         spin_unlock_irqrestore(&free_pages_lock, flags);
 244         return 0;
 245 }
 246
 247 static unsigned long vaddr_page(struct page *page)
 248 {
 249         unsigned long pfn = page_to_pfn(page);
 250
 251         return (unsigned long)pfn_to_kaddr(pfn);
 252 }
 253
 254 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
 255 {
 256         return vaddr_page(req->pages[seg]);
 257 }
 258
 259 static void scsiback_print_status(char *sense_buffer, int errors,
 260                                         struct vscsibk_pend *pending_req)
 261 {
 262         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 263
 264         pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
 265                tpg->tport->tport_name, pending_req->v2p->lun,
 266                pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
 267                host_byte(errors), driver_byte(errors));
 268 }
 269
 270 static void scsiback_fast_flush_area(struct vscsibk_pend *req)
 271 {
 272         struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
 273         struct page *pages[VSCSI_GRANT_BATCH];
 274         unsigned int i, invcount = 0;
 275         grant_handle_t handle;
 276         int err;
 277
 278         kfree(req->sgl);
 279         req->sgl = NULL;
 280         req->n_sg = 0;
 281
 282         if (!req->n_grants)
 283                 return;
 284
 285         for (i = 0; i < req->n_grants; i++) {
 286                 handle = req->grant_handles[i];
 287                 if (handle == SCSIBACK_INVALID_HANDLE)
 288                         continue;
 289                 gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
 290                                     GNTMAP_host_map, handle);
 291                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 292                 pages[invcount] = req->pages[i];
 293                 put_page(pages[invcount]);
 294                 invcount++;
 295                 if (invcount < VSCSI_GRANT_BATCH)
 296                         continue;
 297                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 298                 BUG_ON(err);
 299                 invcount = 0;
 300         }
 301
 302         if (invcount) {
 303                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 304                 BUG_ON(err);
 305         }
 306
 307         put_free_pages(req->pages, req->n_grants);
 308         req->n_grants = 0;
 309 }
 310
 311 static void scsiback_free_translation_entry(struct kref *kref)
 312 {
 313         struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
 314         struct scsiback_tpg *tpg = entry->tpg;
 315
 316         mutex_lock(&tpg->tv_tpg_mutex);
 317         tpg->tv_tpg_fe_count--;
 318         mutex_unlock(&tpg->tv_tpg_mutex);
 319
 320         kfree(entry);
 321 }
 322
 323 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
 324                         uint32_t resid, struct vscsibk_pend *pending_req)
 325 {
 326         struct vscsiif_response *ring_res;
 327         struct vscsibk_info *info = pending_req->info;
 328         int notify;
 329         struct scsi_sense_hdr sshdr;
 330         unsigned long flags;
 331         unsigned len;
 332
 333         spin_lock_irqsave(&info->ring_lock, flags);
 334
 335         ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
 336         info->ring.rsp_prod_pvt++;
 337
 338         ring_res->rslt   = result;
 339         ring_res->rqid   = pending_req->rqid;
 340
 341         if (sense_buffer != NULL &&
 342             scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
 343                                  &sshdr)) {
 344                 len = min_t(unsigned, 8 + sense_buffer[7],
 345                             VSCSIIF_SENSE_BUFFERSIZE);
 346                 memcpy(ring_res->sense_buffer, sense_buffer, len);
 347                 ring_res->sense_len = len;
 348         } else {
 349                 ring_res->sense_len = 0;
 350         }
 351
 352         ring_res->residual_len = resid;
 353
 354         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
 355         spin_unlock_irqrestore(&info->ring_lock, flags);
 356
 357         if (notify)
 358                 notify_remote_via_irq(info->irq);
 359
 360         if (pending_req->v2p)
 361                 kref_put(&pending_req->v2p->kref,
 362                          scsiback_free_translation_entry);
 363 }
 364
 365 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
 366 {
 367         struct vscsibk_info *info = pending_req->info;
 368         unsigned char *sense_buffer;
 369         unsigned int resid;
 370         int errors;
 371
 372         sense_buffer = pending_req->sense_buffer;
 373         resid        = pending_req->se_cmd.residual_count;
 374         errors       = pending_req->result;
 375
 376         if (errors && log_print_stat)
 377                 scsiback_print_status(sense_buffer, errors, pending_req);
 378
 379         scsiback_fast_flush_area(pending_req);
 380         scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
 381         scsiback_put(info);
 382 }
 383
 384 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
 385 {
 386         struct se_cmd *se_cmd = &pending_req->se_cmd;
 387         struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
 388         int rc;
 389
 390         memset(pending_req->sense_buffer, 0, VSCSIIF_SENSE_BUFFERSIZE);
 391
 392         memset(se_cmd, 0, sizeof(*se_cmd));
 393
 394         scsiback_get(pending_req->info);
 395         se_cmd->tag = pending_req->rqid;
 396         rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,
 397                         pending_req->sense_buffer, pending_req->v2p->lun,
 398                         pending_req->data_len, 0,
 399                         pending_req->sc_data_direction, 0,
 400                         pending_req->sgl, pending_req->n_sg,
 401                         NULL, 0, NULL, 0);
 402         if (rc < 0) {
 403                 transport_send_check_condition_and_sense(se_cmd,
 404                                 TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
 405                 transport_generic_free_cmd(se_cmd, 0);
 406         }
 407 }
 408
 409 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 410         struct page **pg, grant_handle_t *grant, int cnt)
 411 {
 412         int err, i;
 413
 414         if (!cnt)
 415                 return 0;
 416
 417         err = gnttab_map_refs(map, NULL, pg, cnt);
 418         for (i = 0; i < cnt; i++) {
 419                 if (unlikely(map[i].status != GNTST_okay)) {
 420                         pr_err("invalid buffer -- could not remap it\n");
 421                         map[i].handle = SCSIBACK_INVALID_HANDLE;
 422                         if (!err)
 423                                 err = -ENOMEM;
 424                 } else {
 425                         get_page(pg[i]);
 426                 }
 427                 grant[i] = map[i].handle;
 428         }
 429         return err;
 430 }
 431
 432 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
 433                         struct scsiif_request_segment *seg, struct page **pg,
 434                         grant_handle_t *grant, int cnt, u32 flags)
 435 {
 436         int mapcount = 0, i, err = 0;
 437         struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
 438         struct vscsibk_info *info = pending_req->info;
 439
 440         for (i = 0; i < cnt; i++) {
 441                 if (get_free_page(pg + mapcount)) {
 442                         put_free_pages(pg, mapcount);
 443                         pr_err("no grant page\n");
 444                         return -ENOMEM;
 445                 }
 446                 gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
 447                                   flags, seg[i].gref, info->domid);
 448                 mapcount++;
 449                 if (mapcount < VSCSI_GRANT_BATCH)
 450                         continue;
 451                 err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 452                 pg += mapcount;
 453                 grant += mapcount;
 454                 pending_req->n_grants += mapcount;
 455                 if (err)
 456                         return err;
 457                 mapcount = 0;
 458         }
 459         err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 460         pending_req->n_grants += mapcount;
 461         return err;
 462 }
 463
 464 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 465                                         struct vscsibk_pend *pending_req)
 466 {
 467         u32 flags;
 468         int i, err, n_segs, i_seg = 0;
 469         struct page **pg;
 470         struct scsiif_request_segment *seg;
 471         unsigned long end_seg = 0;
 472         unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
 473         unsigned int nr_sgl = 0;
 474         struct scatterlist *sg;
 475         grant_handle_t *grant;
 476
 477         pending_req->n_sg = 0;
 478         pending_req->n_grants = 0;
 479         pending_req->data_len = 0;
 480
 481         nr_segments &= ~VSCSIIF_SG_GRANT;
 482         if (!nr_segments)
 483                 return 0;
 484
 485         if (nr_segments > VSCSIIF_SG_TABLESIZE) {
 486                 pr_debug("invalid parameter nr_seg = %d\n",
 487                         ring_req->nr_segments);
 488                 return -EINVAL;
 489         }
 490
 491         if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
 492                 err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
 493                         pending_req->pages, pending_req->grant_handles,
 494                         nr_segments, GNTMAP_host_map | GNTMAP_readonly);
 495                 if (err)
 496                         return err;
 497                 nr_sgl = nr_segments;
 498                 nr_segments = 0;
 499                 for (i = 0; i < nr_sgl; i++) {
 500                         n_segs = ring_req->seg[i].length /
 501                                  sizeof(struct scsiif_request_segment);
 502                         if ((unsigned)ring_req->seg[i].offset +
 503                             (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
 504                             n_segs * sizeof(struct scsiif_request_segment) !=
 505                             ring_req->seg[i].length)
 506                                 return -EINVAL;
 507                         nr_segments += n_segs;
 508                 }
 509                 if (nr_segments > SG_ALL) {
 510                         pr_debug("invalid nr_seg = %d\n", nr_segments);
 511                         return -EINVAL;
 512                 }
 513         }
 514
 515         /* free of (sgl) in fast_flush_area() */
 516         pending_req->sgl = kmalloc_array(nr_segments,
 517                                         sizeof(struct scatterlist), GFP_KERNEL);
 518         if (!pending_req->sgl)
 519                 return -ENOMEM;
 520
 521         sg_init_table(pending_req->sgl, nr_segments);
 522         pending_req->n_sg = nr_segments;
 523
 524         flags = GNTMAP_host_map;
 525         if (pending_req->sc_data_direction == DMA_TO_DEVICE)
 526                 flags |= GNTMAP_readonly;
 527
 528         pg = pending_req->pages + nr_sgl;
 529         grant = pending_req->grant_handles + nr_sgl;
 530         if (!nr_sgl) {
 531                 seg = ring_req->seg;
 532                 err = scsiback_gnttab_data_map_list(pending_req, seg,
 533                         pg, grant, nr_segments, flags);
 534                 if (err)
 535                         return err;
 536         } else {
 537                 for (i = 0; i < nr_sgl; i++) {
 538                         seg = (struct scsiif_request_segment *)(
 539                               vaddr(pending_req, i) + ring_req->seg[i].offset);
 540                         n_segs = ring_req->seg[i].length /
 541                                  sizeof(struct scsiif_request_segment);
 542                         err = scsiback_gnttab_data_map_list(pending_req, seg,
 543                                 pg, grant, n_segs, flags);
 544                         if (err)
 545                                 return err;
 546                         pg += n_segs;
 547                         grant += n_segs;
 548                 }
 549                 end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
 550                 seg = (struct scsiif_request_segment *)end_seg;
 551                 end_seg += ring_req->seg[0].length;
 552                 pg = pending_req->pages + nr_sgl;
 553         }
 554
 555         for_each_sg(pending_req->sgl, sg, nr_segments, i) {
 556                 sg_set_page(sg, pg[i], seg->length, seg->offset);
 557                 pending_req->data_len += seg->length;
 558                 seg++;
 559                 if (nr_sgl && (unsigned long)seg >= end_seg) {
 560                         i_seg++;
 561                         end_seg = vaddr(pending_req, i_seg) +
 562                                   ring_req->seg[i_seg].offset;
 563                         seg = (struct scsiif_request_segment *)end_seg;
 564                         end_seg += ring_req->seg[i_seg].length;
 565                 }
 566                 if (sg->offset >= PAGE_SIZE ||
 567                     sg->length > PAGE_SIZE ||
 568                     sg->offset + sg->length > PAGE_SIZE)
 569                         return -EINVAL;
 570         }
 571
 572         return 0;
 573 }
 574
 575 static void scsiback_disconnect(struct vscsibk_info *info)
 576 {
 577         wait_event(info->waiting_to_free,
 578                 atomic_read(&info->nr_unreplied_reqs) == 0);
 579
 580         unbind_from_irqhandler(info->irq, info);
 581         info->irq = 0;
 582         xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
 583 }
 584
 585 static void scsiback_device_action(struct vscsibk_pend *pending_req,
 586         enum tcm_tmreq_table act, int tag)
 587 {
 588         int rc, err = FAILED;
 589         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 590         struct se_cmd *se_cmd = &pending_req->se_cmd;
 591         struct scsiback_tmr *tmr;
 592
 593         tmr = kzalloc(sizeof(struct scsiback_tmr), GFP_KERNEL);
 594         if (!tmr)
 595                 goto out;
 596
 597         init_waitqueue_head(&tmr->tmr_wait);
 598
 599         transport_init_se_cmd(se_cmd, tpg->se_tpg.se_tpg_tfo,
 600                 tpg->tpg_nexus->tvn_se_sess, 0, DMA_NONE, TCM_SIMPLE_TAG,
 601                 &pending_req->sense_buffer[0]);
 602
 603         rc = core_tmr_alloc_req(se_cmd, tmr, act, GFP_KERNEL);
 604         if (rc < 0)
 605                 goto out;
 606
 607         se_cmd->se_tmr_req->ref_task_tag = tag;
 608
 609         if (transport_lookup_tmr_lun(se_cmd, pending_req->v2p->lun) < 0)
 610                 goto out;
 611
 612         transport_generic_handle_tmr(se_cmd);
 613         wait_event(tmr->tmr_wait, atomic_read(&tmr->tmr_complete));
 614
 615         err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
 616                 SUCCESS : FAILED;
 617
 618 out:
 619         if (tmr) {
 620                 transport_generic_free_cmd(&pending_req->se_cmd, 1);
 621                 kfree(tmr);
 622         }
 623
 624         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 625
 626         kmem_cache_free(scsiback_cachep, pending_req);
 627 }
 628
 629 /*
 630   Perform virtual to physical translation
 631 */
 632 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
 633                         struct ids_tuple *v)
 634 {
 635         struct v2p_entry *entry;
 636         struct list_head *head = &(info->v2p_entry_lists);
 637         unsigned long flags;
 638
 639         spin_lock_irqsave(&info->v2p_lock, flags);
 640         list_for_each_entry(entry, head, l) {
 641                 if ((entry->v.chn == v->chn) &&
 642                     (entry->v.tgt == v->tgt) &&
 643                     (entry->v.lun == v->lun)) {
 644                         kref_get(&entry->kref);
 645                         goto out;
 646                 }
 647         }
 648         entry = NULL;
 649
 650 out:
 651         spin_unlock_irqrestore(&info->v2p_lock, flags);
 652         return entry;
 653 }
 654
 655 static int prepare_pending_reqs(struct vscsibk_info *info,
 656                                 struct vscsiif_request *ring_req,
 657                                 struct vscsibk_pend *pending_req)
 658 {
 659         struct v2p_entry *v2p;
 660         struct ids_tuple vir;
 661
 662         pending_req->rqid       = ring_req->rqid;
 663         pending_req->info       = info;
 664
 665         vir.chn = ring_req->channel;
 666         vir.tgt = ring_req->id;
 667         vir.lun = ring_req->lun;
 668
 669         v2p = scsiback_do_translation(info, &vir);
 670         if (!v2p) {
 671                 pending_req->v2p = NULL;
 672                 pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
 673                         vir.chn, vir.tgt, vir.lun);
 674                 return -ENODEV;
 675         }
 676         pending_req->v2p = v2p;
 677
 678         /* request range check from frontend */
 679         pending_req->sc_data_direction = ring_req->sc_data_direction;
 680         if ((pending_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
 681                 (pending_req->sc_data_direction != DMA_TO_DEVICE) &&
 682                 (pending_req->sc_data_direction != DMA_FROM_DEVICE) &&
 683                 (pending_req->sc_data_direction != DMA_NONE)) {
 684                 pr_debug("invalid parameter data_dir = %d\n",
 685                         pending_req->sc_data_direction);
 686                 return -EINVAL;
 687         }
 688
 689         pending_req->cmd_len = ring_req->cmd_len;
 690         if (pending_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
 691                 pr_debug("invalid parameter cmd_len = %d\n",
 692                         pending_req->cmd_len);
 693                 return -EINVAL;
 694         }
 695         memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
 696
 697         return 0;
 698 }
 699
 700 static int scsiback_do_cmd_fn(struct vscsibk_info *info,
 701                               unsigned int *eoi_flags)
 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                 return -EINVAL;
 719         }
 720
 721         while ((rc != rp)) {
 722                 *eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS;
 723
 724                 if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
 725                         break;
 726                 pending_req = kmem_cache_alloc(scsiback_cachep, GFP_KERNEL);
 727                 if (!pending_req)
 728                         return 1;
 729
 730                 RING_COPY_REQUEST(ring, rc, &ring_req);
 731                 ring->req_cons = ++rc;
 732
 733                 err = prepare_pending_reqs(info, &ring_req, pending_req);
 734                 if (err) {
 735                         switch (err) {
 736                         case -ENODEV:
 737                                 result = DID_NO_CONNECT;
 738                                 break;
 739                         default:
 740                                 result = DRIVER_ERROR;
 741                                 break;
 742                         }
 743                         scsiback_do_resp_with_sense(NULL, result << 24, 0,
 744                                                     pending_req);
 745                         kmem_cache_free(scsiback_cachep, pending_req);
 746                         return 1;
 747                 }
 748
 749                 switch (ring_req.act) {
 750                 case VSCSIIF_ACT_SCSI_CDB:
 751                         if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
 752                                 scsiback_fast_flush_area(pending_req);
 753                                 scsiback_do_resp_with_sense(NULL,
 754                                         DRIVER_ERROR << 24, 0, pending_req);
 755                                 kmem_cache_free(scsiback_cachep, pending_req);
 756                         } else {
 757                                 scsiback_cmd_exec(pending_req);
 758                         }
 759                         break;
 760                 case VSCSIIF_ACT_SCSI_ABORT:
 761                         scsiback_device_action(pending_req, TMR_ABORT_TASK,
 762                                 ring_req.ref_rqid);
 763                         break;
 764                 case VSCSIIF_ACT_SCSI_RESET:
 765                         scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
 766                         break;
 767                 default:
 768                         pr_err_ratelimited("invalid request\n");
 769                         scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24,
 770                                                     0, pending_req);
 771                         kmem_cache_free(scsiback_cachep, pending_req);
 772                         break;
 773                 }
 774
 775                 /* Yield point for this unbounded loop. */
 776                 cond_resched();
 777         }
 778
 779         RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
 780         return more_to_do;
 781 }
 782
 783 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
 784 {
 785         struct vscsibk_info *info = dev_id;
 786         int rc;
 787         unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
 788
 789         while ((rc = scsiback_do_cmd_fn(info, &eoi_flags)) > 0)
 790                 cond_resched();
 791
 792         /* In case of a ring error we keep the event channel masked. */
 793         if (!rc)
 794                 xen_irq_lateeoi(irq, eoi_flags);
 795
 796         return IRQ_HANDLED;
 797 }
 798
 799 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 800                         evtchn_port_t evtchn)
 801 {
 802         void *area;
 803         struct vscsiif_sring *sring;
 804         int err;
 805
 806         if (info->irq)
 807                 return -1;
 808
 809         err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 810         if (err)
 811                 return err;
 812
 813         sring = (struct vscsiif_sring *)area;
 814         BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 815
 816         err = bind_interdomain_evtchn_to_irq_lateeoi(info->domid, evtchn);
 817         if (err < 0)
 818                 goto unmap_page;
 819
 820         info->irq = err;
 821
 822         err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
 823                                    IRQF_ONESHOT, "vscsiif-backend", info);
 824         if (err)
 825                 goto free_irq;
 826
 827         return 0;
 828
 829 free_irq:
 830         unbind_from_irqhandler(info->irq, info);
 831         info->irq = 0;
 832 unmap_page:
 833         xenbus_unmap_ring_vfree(info->dev, area);
 834
 835         return err;
 836 }
 837
 838 static int scsiback_map(struct vscsibk_info *info)
 839 {
 840         struct xenbus_device *dev = info->dev;
 841         unsigned int ring_ref, evtchn;
 842         int err;
 843
 844         err = xenbus_gather(XBT_NIL, dev->otherend,
 845                         "ring-ref", "%u", &ring_ref,
 846                         "event-channel", "%u", &evtchn, NULL);
 847         if (err) {
 848                 xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
 849                 return err;
 850         }
 851
 852         return scsiback_init_sring(info, ring_ref, evtchn);
 853 }
 854
 855 /*
 856   Add a new translation entry
 857 */
 858 static int scsiback_add_translation_entry(struct vscsibk_info *info,
 859                                           char *phy, struct ids_tuple *v)
 860 {
 861         int err = 0;
 862         struct v2p_entry *entry;
 863         struct v2p_entry *new;
 864         struct list_head *head = &(info->v2p_entry_lists);
 865         unsigned long flags;
 866         char *lunp;
 867         unsigned long long unpacked_lun;
 868         struct se_lun *se_lun;
 869         struct scsiback_tpg *tpg_entry, *tpg = NULL;
 870         char *error = "doesn't exist";
 871
 872         lunp = strrchr(phy, ':');
 873         if (!lunp) {
 874                 pr_err("illegal format of physical device %s\n", phy);
 875                 return -EINVAL;
 876         }
 877         *lunp = 0;
 878         lunp++;
 879         err = kstrtoull(lunp, 10, &unpacked_lun);
 880         if (err < 0) {
 881                 pr_err("lun number not valid: %s\n", lunp);
 882                 return err;
 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                         mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
 890                         hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
 891                                 if (se_lun->unpacked_lun == unpacked_lun) {
 892                                         if (!tpg_entry->tpg_nexus)
 893                                                 error = "nexus undefined";
 894                                         else
 895                                                 tpg = tpg_entry;
 896                                         break;
 897                                 }
 898                         }
 899                         mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
 900                         break;
 901                 }
 902         }
 903         if (tpg) {
 904                 mutex_lock(&tpg->tv_tpg_mutex);
 905                 tpg->tv_tpg_fe_count++;
 906                 mutex_unlock(&tpg->tv_tpg_mutex);
 907         }
 908         mutex_unlock(&scsiback_mutex);
 909
 910         if (!tpg) {
 911                 pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
 912                 return -ENODEV;
 913         }
 914
 915         new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
 916         if (new == NULL) {
 917                 err = -ENOMEM;
 918                 goto out_free;
 919         }
 920
 921         spin_lock_irqsave(&info->v2p_lock, flags);
 922
 923         /* Check double assignment to identical virtual ID */
 924         list_for_each_entry(entry, head, l) {
 925                 if ((entry->v.chn == v->chn) &&
 926                     (entry->v.tgt == v->tgt) &&
 927                     (entry->v.lun == v->lun)) {
 928                         pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 929                         err = -EEXIST;
 930                         goto out;
 931                 }
 932
 933         }
 934
 935         /* Create a new translation entry and add to the list */
 936         kref_init(&new->kref);
 937         new->v = *v;
 938         new->tpg = tpg;
 939         new->lun = unpacked_lun;
 940         list_add_tail(&new->l, head);
 941
 942 out:
 943         spin_unlock_irqrestore(&info->v2p_lock, flags);
 944
 945 out_free:
 946         if (err) {
 947                 mutex_lock(&tpg->tv_tpg_mutex);
 948                 tpg->tv_tpg_fe_count--;
 949                 mutex_unlock(&tpg->tv_tpg_mutex);
 950                 kfree(new);
 951         }
 952
 953         return err;
 954 }
 955
 956 static void __scsiback_del_translation_entry(struct v2p_entry *entry)
 957 {
 958         list_del(&entry->l);
 959         kref_put(&entry->kref, scsiback_free_translation_entry);
 960 }
 961
 962 /*
 963   Delete the translation entry specfied
 964 */
 965 static int scsiback_del_translation_entry(struct vscsibk_info *info,
 966                                           struct ids_tuple *v)
 967 {
 968         struct v2p_entry *entry;
 969         struct list_head *head = &(info->v2p_entry_lists);
 970         unsigned long flags;
 971
 972         spin_lock_irqsave(&info->v2p_lock, flags);
 973         /* Find out the translation entry specified */
 974         list_for_each_entry(entry, head, l) {
 975                 if ((entry->v.chn == v->chn) &&
 976                     (entry->v.tgt == v->tgt) &&
 977                     (entry->v.lun == v->lun)) {
 978                         goto found;
 979                 }
 980         }
 981
 982         spin_unlock_irqrestore(&info->v2p_lock, flags);
 983         return 1;
 984
 985 found:
 986         /* Delete the translation entry specfied */
 987         __scsiback_del_translation_entry(entry);
 988
 989         spin_unlock_irqrestore(&info->v2p_lock, flags);
 990         return 0;
 991 }
 992
 993 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
 994                                 char *phy, struct ids_tuple *vir, int try)
 995 {
 996         if (!scsiback_add_translation_entry(info, phy, vir)) {
 997                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
 998                                   "%d", XenbusStateInitialised)) {
 999                         pr_err("xenbus_printf error %s\n", state);
1000                         scsiback_del_translation_entry(info, vir);
1001                 }
1002         } else if (!try) {
1003                 xenbus_printf(XBT_NIL, info->dev->nodename, state,
1004                               "%d", XenbusStateClosed);
1005         }
1006 }
1007
1008 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1009                                 struct ids_tuple *vir)
1010 {
1011         if (!scsiback_del_translation_entry(info, vir)) {
1012                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1013                                   "%d", XenbusStateClosed))
1014                         pr_err("xenbus_printf error %s\n", state);
1015         }
1016 }
1017
1018 #define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1019 #define VSCSIBACK_OP_UPDATEDEV_STATE    2
1020
1021 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1022                                      char *ent)
1023 {
1024         int err;
1025         struct ids_tuple vir;
1026         char *val;
1027         int device_state;
1028         char phy[VSCSI_NAMELEN];
1029         char str[64];
1030         char state[64];
1031         struct xenbus_device *dev = info->dev;
1032
1033         /* read status */
1034         snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1035         err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1036         if (XENBUS_EXIST_ERR(err))
1037                 return;
1038
1039         /* physical SCSI device */
1040         snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1041         val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1042         if (IS_ERR(val)) {
1043                 xenbus_printf(XBT_NIL, dev->nodename, state,
1044                               "%d", XenbusStateClosed);
1045                 return;
1046         }
1047         strlcpy(phy, val, VSCSI_NAMELEN);
1048         kfree(val);
1049
1050         /* virtual SCSI device */
1051         snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1052         err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1053                            &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1054         if (XENBUS_EXIST_ERR(err)) {
1055                 xenbus_printf(XBT_NIL, dev->nodename, state,
1056                               "%d", XenbusStateClosed);
1057                 return;
1058         }
1059
1060         switch (op) {
1061         case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1062                 switch (device_state) {
1063                 case XenbusStateInitialising:
1064                         scsiback_do_add_lun(info, state, phy, &vir, 0);
1065                         break;
1066                 case XenbusStateConnected:
1067                         scsiback_do_add_lun(info, state, phy, &vir, 1);
1068                         break;
1069                 case XenbusStateClosing:
1070                         scsiback_do_del_lun(info, state, &vir);
1071                         break;
1072                 default:
1073                         break;
1074                 }
1075                 break;
1076
1077         case VSCSIBACK_OP_UPDATEDEV_STATE:
1078                 if (device_state == XenbusStateInitialised) {
1079                         /* modify vscsi-devs/dev-x/state */
1080                         if (xenbus_printf(XBT_NIL, dev->nodename, state,
1081                                           "%d", XenbusStateConnected)) {
1082                                 pr_err("xenbus_printf error %s\n", str);
1083                                 scsiback_del_translation_entry(info, &vir);
1084                                 xenbus_printf(XBT_NIL, dev->nodename, state,
1085                                               "%d", XenbusStateClosed);
1086                         }
1087                 }
1088                 break;
1089         /* When it is necessary, processing is added here. */
1090         default:
1091                 break;
1092         }
1093 }
1094
1095 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1096 {
1097         int i;
1098         char **dir;
1099         unsigned int ndir = 0;
1100
1101         dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1102                                &ndir);
1103         if (IS_ERR(dir))
1104                 return;
1105
1106         for (i = 0; i < ndir; i++)
1107                 scsiback_do_1lun_hotplug(info, op, dir[i]);
1108
1109         kfree(dir);
1110 }
1111
1112 static void scsiback_frontend_changed(struct xenbus_device *dev,
1113                                         enum xenbus_state frontend_state)
1114 {
1115         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1116
1117         switch (frontend_state) {
1118         case XenbusStateInitialising:
1119                 break;
1120
1121         case XenbusStateInitialised:
1122                 if (scsiback_map(info))
1123                         break;
1124
1125                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1126                 xenbus_switch_state(dev, XenbusStateConnected);
1127                 break;
1128
1129         case XenbusStateConnected:
1130                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1131
1132                 if (dev->state == XenbusStateConnected)
1133                         break;
1134
1135                 xenbus_switch_state(dev, XenbusStateConnected);
1136                 break;
1137
1138         case XenbusStateClosing:
1139                 if (info->irq)
1140                         scsiback_disconnect(info);
1141
1142                 xenbus_switch_state(dev, XenbusStateClosing);
1143                 break;
1144
1145         case XenbusStateClosed:
1146                 xenbus_switch_state(dev, XenbusStateClosed);
1147                 if (xenbus_dev_is_online(dev))
1148                         break;
1149                 /* fall through if not online */
1150         case XenbusStateUnknown:
1151                 device_unregister(&dev->dev);
1152                 break;
1153
1154         case XenbusStateReconfiguring:
1155                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1156                 xenbus_switch_state(dev, XenbusStateReconfigured);
1157
1158                 break;
1159
1160         default:
1161                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1162                                         frontend_state);
1163                 break;
1164         }
1165 }
1166
1167 /*
1168   Release the translation entry specfied
1169 */
1170 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1171 {
1172         struct v2p_entry *entry, *tmp;
1173         struct list_head *head = &(info->v2p_entry_lists);
1174         unsigned long flags;
1175
1176         spin_lock_irqsave(&info->v2p_lock, flags);
1177
1178         list_for_each_entry_safe(entry, tmp, head, l)
1179                 __scsiback_del_translation_entry(entry);
1180
1181         spin_unlock_irqrestore(&info->v2p_lock, flags);
1182 }
1183
1184 static int scsiback_remove(struct xenbus_device *dev)
1185 {
1186         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1187
1188         if (info->irq)
1189                 scsiback_disconnect(info);
1190
1191         scsiback_release_translation_entry(info);
1192
1193         dev_set_drvdata(&dev->dev, NULL);
1194
1195         return 0;
1196 }
1197
1198 static int scsiback_probe(struct xenbus_device *dev,
1199                            const struct xenbus_device_id *id)
1200 {
1201         int err;
1202
1203         struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1204                                             GFP_KERNEL);
1205
1206         pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1207
1208         if (!info) {
1209                 xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1210                 return -ENOMEM;
1211         }
1212         info->dev = dev;
1213         dev_set_drvdata(&dev->dev, info);
1214
1215         info->domid = dev->otherend_id;
1216         spin_lock_init(&info->ring_lock);
1217         atomic_set(&info->nr_unreplied_reqs, 0);
1218         init_waitqueue_head(&info->waiting_to_free);
1219         info->dev = dev;
1220         info->irq = 0;
1221         INIT_LIST_HEAD(&info->v2p_entry_lists);
1222         spin_lock_init(&info->v2p_lock);
1223
1224         err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1225                             SG_ALL);
1226         if (err)
1227                 xenbus_dev_error(dev, err, "writing feature-sg-grant");
1228
1229         err = xenbus_switch_state(dev, XenbusStateInitWait);
1230         if (err)
1231                 goto fail;
1232
1233         return 0;
1234
1235 fail:
1236         pr_warn("%s failed\n", __func__);
1237         scsiback_remove(dev);
1238
1239         return err;
1240 }
1241
1242 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1243 {
1244         switch (tport->tport_proto_id) {
1245         case SCSI_PROTOCOL_SAS:
1246                 return "SAS";
1247         case SCSI_PROTOCOL_FCP:
1248                 return "FCP";
1249         case SCSI_PROTOCOL_ISCSI:
1250                 return "iSCSI";
1251         default:
1252                 break;
1253         }
1254
1255         return "Unknown";
1256 }
1257
1258 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1259 {
1260         struct scsiback_tpg *tpg = container_of(se_tpg,
1261                                 struct scsiback_tpg, se_tpg);
1262         struct scsiback_tport *tport = tpg->tport;
1263
1264         return &tport->tport_name[0];
1265 }
1266
1267 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1268 {
1269         struct scsiback_tpg *tpg = container_of(se_tpg,
1270                                 struct scsiback_tpg, se_tpg);
1271         return tpg->tport_tpgt;
1272 }
1273
1274 static struct se_wwn *
1275 scsiback_make_tport(struct target_fabric_configfs *tf,
1276                      struct config_group *group,
1277                      const char *name)
1278 {
1279         struct scsiback_tport *tport;
1280         char *ptr;
1281         u64 wwpn = 0;
1282         int off = 0;
1283
1284         tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1285         if (!tport)
1286                 return ERR_PTR(-ENOMEM);
1287
1288         tport->tport_wwpn = wwpn;
1289         /*
1290          * Determine the emulated Protocol Identifier and Target Port Name
1291          * based on the incoming configfs directory name.
1292          */
1293         ptr = strstr(name, "naa.");
1294         if (ptr) {
1295                 tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1296                 goto check_len;
1297         }
1298         ptr = strstr(name, "fc.");
1299         if (ptr) {
1300                 tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1301                 off = 3; /* Skip over "fc." */
1302                 goto check_len;
1303         }
1304         ptr = strstr(name, "iqn.");
1305         if (ptr) {
1306                 tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1307                 goto check_len;
1308         }
1309
1310         pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1311         kfree(tport);
1312         return ERR_PTR(-EINVAL);
1313
1314 check_len:
1315         if (strlen(name) >= VSCSI_NAMELEN) {
1316                 pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1317                         scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1318                 kfree(tport);
1319                 return ERR_PTR(-EINVAL);
1320         }
1321         snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1322
1323         pr_debug("Allocated emulated Target %s Address: %s\n",
1324                  scsiback_dump_proto_id(tport), name);
1325
1326         return &tport->tport_wwn;
1327 }
1328
1329 static void scsiback_drop_tport(struct se_wwn *wwn)
1330 {
1331         struct scsiback_tport *tport = container_of(wwn,
1332                                 struct scsiback_tport, tport_wwn);
1333
1334         pr_debug("Deallocating emulated Target %s Address: %s\n",
1335                  scsiback_dump_proto_id(tport), tport->tport_name);
1336
1337         kfree(tport);
1338 }
1339
1340 static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1341 {
1342         return 1;
1343 }
1344
1345 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1346 {
1347         /*
1348          * Do not release struct se_cmd's containing a valid TMR pointer.
1349          * These will be released directly in scsiback_device_action()
1350          * with transport_generic_free_cmd().
1351          */
1352         if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
1353                 return 0;
1354
1355         transport_generic_free_cmd(se_cmd, 0);
1356         return 1;
1357 }
1358
1359 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1360 {
1361         struct vscsibk_pend *pending_req = container_of(se_cmd,
1362                                 struct vscsibk_pend, se_cmd);
1363
1364         kmem_cache_free(scsiback_cachep, pending_req);
1365 }
1366
1367 static int scsiback_shutdown_session(struct se_session *se_sess)
1368 {
1369         return 0;
1370 }
1371
1372 static void scsiback_close_session(struct se_session *se_sess)
1373 {
1374 }
1375
1376 static u32 scsiback_sess_get_index(struct se_session *se_sess)
1377 {
1378         return 0;
1379 }
1380
1381 static int scsiback_write_pending(struct se_cmd *se_cmd)
1382 {
1383         /* Go ahead and process the write immediately */
1384         target_execute_cmd(se_cmd);
1385
1386         return 0;
1387 }
1388
1389 static int scsiback_write_pending_status(struct se_cmd *se_cmd)
1390 {
1391         return 0;
1392 }
1393
1394 static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1395 {
1396 }
1397
1398 static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1399 {
1400         return 0;
1401 }
1402
1403 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1404 {
1405         struct vscsibk_pend *pending_req = container_of(se_cmd,
1406                                 struct vscsibk_pend, se_cmd);
1407
1408         pending_req->result = SAM_STAT_GOOD;
1409         scsiback_cmd_done(pending_req);
1410         return 0;
1411 }
1412
1413 static int scsiback_queue_status(struct se_cmd *se_cmd)
1414 {
1415         struct vscsibk_pend *pending_req = container_of(se_cmd,
1416                                 struct vscsibk_pend, se_cmd);
1417
1418         if (se_cmd->sense_buffer &&
1419             ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1420              (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1421                 pending_req->result = (DRIVER_SENSE << 24) |
1422                                       SAM_STAT_CHECK_CONDITION;
1423         else
1424                 pending_req->result = se_cmd->scsi_status;
1425
1426         scsiback_cmd_done(pending_req);
1427         return 0;
1428 }
1429
1430 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1431 {
1432         struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
1433         struct scsiback_tmr *tmr = se_tmr->fabric_tmr_ptr;
1434
1435         atomic_set(&tmr->tmr_complete, 1);
1436         wake_up(&tmr->tmr_wait);
1437 }
1438
1439 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1440 {
1441 }
1442
1443 static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1444                                              char *page)
1445 {
1446         struct se_portal_group *se_tpg = param_to_tpg(item);
1447         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1448                                                 se_tpg);
1449         ssize_t rb;
1450
1451         mutex_lock(&tpg->tv_tpg_mutex);
1452         rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1453         mutex_unlock(&tpg->tv_tpg_mutex);
1454
1455         return rb;
1456 }
1457
1458 static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1459                                               const char *page, size_t count)
1460 {
1461         struct se_portal_group *se_tpg = param_to_tpg(item);
1462         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1463                                                 se_tpg);
1464         int len;
1465
1466         if (strlen(page) >= VSCSI_NAMELEN) {
1467                 pr_err("param alias: %s, exceeds max: %d\n", page,
1468                         VSCSI_NAMELEN);
1469                 return -EINVAL;
1470         }
1471
1472         mutex_lock(&tpg->tv_tpg_mutex);
1473         len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1474         if (tpg->param_alias[len - 1] == '\n')
1475                 tpg->param_alias[len - 1] = '\0';
1476         mutex_unlock(&tpg->tv_tpg_mutex);
1477
1478         return count;
1479 }
1480
1481 CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1482
1483 static struct configfs_attribute *scsiback_param_attrs[] = {
1484         &scsiback_tpg_param_attr_alias,
1485         NULL,
1486 };
1487
1488 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1489                                 const char *name)
1490 {
1491         struct se_portal_group *se_tpg;
1492         struct se_session *se_sess;
1493         struct scsiback_nexus *tv_nexus;
1494
1495         mutex_lock(&tpg->tv_tpg_mutex);
1496         if (tpg->tpg_nexus) {
1497                 mutex_unlock(&tpg->tv_tpg_mutex);
1498                 pr_debug("tpg->tpg_nexus already exists\n");
1499                 return -EEXIST;
1500         }
1501         se_tpg = &tpg->se_tpg;
1502
1503         tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1504         if (!tv_nexus) {
1505                 mutex_unlock(&tpg->tv_tpg_mutex);
1506                 return -ENOMEM;
1507         }
1508         /*
1509          * Initialize the struct se_session pointer
1510          */
1511         tv_nexus->tvn_se_sess = transport_init_session(TARGET_PROT_NORMAL);
1512         if (IS_ERR(tv_nexus->tvn_se_sess)) {
1513                 mutex_unlock(&tpg->tv_tpg_mutex);
1514                 kfree(tv_nexus);
1515                 return -ENOMEM;
1516         }
1517         se_sess = tv_nexus->tvn_se_sess;
1518         /*
1519          * Since we are running in 'demo mode' this call with generate a
1520          * struct se_node_acl for the scsiback struct se_portal_group with
1521          * the SCSI Initiator port name of the passed configfs group 'name'.
1522          */
1523         tv_nexus->tvn_se_sess->se_node_acl = core_tpg_check_initiator_node_acl(
1524                                 se_tpg, (unsigned char *)name);
1525         if (!tv_nexus->tvn_se_sess->se_node_acl) {
1526                 mutex_unlock(&tpg->tv_tpg_mutex);
1527                 pr_debug("core_tpg_check_initiator_node_acl() failed for %s\n",
1528                          name);
1529                 goto out;
1530         }
1531         /* Now register the TCM pvscsi virtual I_T Nexus as active. */
1532         transport_register_session(se_tpg, tv_nexus->tvn_se_sess->se_node_acl,
1533                         tv_nexus->tvn_se_sess, tv_nexus);
1534         tpg->tpg_nexus = tv_nexus;
1535
1536         mutex_unlock(&tpg->tv_tpg_mutex);
1537         return 0;
1538
1539 out:
1540         transport_free_session(se_sess);
1541         kfree(tv_nexus);
1542         return -ENOMEM;
1543 }
1544
1545 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1546 {
1547         struct se_session *se_sess;
1548         struct scsiback_nexus *tv_nexus;
1549
1550         mutex_lock(&tpg->tv_tpg_mutex);
1551         tv_nexus = tpg->tpg_nexus;
1552         if (!tv_nexus) {
1553                 mutex_unlock(&tpg->tv_tpg_mutex);
1554                 return -ENODEV;
1555         }
1556
1557         se_sess = tv_nexus->tvn_se_sess;
1558         if (!se_sess) {
1559                 mutex_unlock(&tpg->tv_tpg_mutex);
1560                 return -ENODEV;
1561         }
1562
1563         if (tpg->tv_tpg_port_count != 0) {
1564                 mutex_unlock(&tpg->tv_tpg_mutex);
1565                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1566                         tpg->tv_tpg_port_count);
1567                 return -EBUSY;
1568         }
1569
1570         if (tpg->tv_tpg_fe_count != 0) {
1571                 mutex_unlock(&tpg->tv_tpg_mutex);
1572                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1573                         tpg->tv_tpg_fe_count);
1574                 return -EBUSY;
1575         }
1576
1577         pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1578                 scsiback_dump_proto_id(tpg->tport),
1579                 tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1580
1581         /*
1582          * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1583          */
1584         transport_deregister_session(tv_nexus->tvn_se_sess);
1585         tpg->tpg_nexus = NULL;
1586         mutex_unlock(&tpg->tv_tpg_mutex);
1587
1588         kfree(tv_nexus);
1589         return 0;
1590 }
1591
1592 static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1593 {
1594         struct se_portal_group *se_tpg = to_tpg(item);
1595         struct scsiback_tpg *tpg = container_of(se_tpg,
1596                                 struct scsiback_tpg, se_tpg);
1597         struct scsiback_nexus *tv_nexus;
1598         ssize_t ret;
1599
1600         mutex_lock(&tpg->tv_tpg_mutex);
1601         tv_nexus = tpg->tpg_nexus;
1602         if (!tv_nexus) {
1603                 mutex_unlock(&tpg->tv_tpg_mutex);
1604                 return -ENODEV;
1605         }
1606         ret = snprintf(page, PAGE_SIZE, "%s\n",
1607                         tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1608         mutex_unlock(&tpg->tv_tpg_mutex);
1609
1610         return ret;
1611 }
1612
1613 static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
1614                 const char *page, size_t count)
1615 {
1616         struct se_portal_group *se_tpg = to_tpg(item);
1617         struct scsiback_tpg *tpg = container_of(se_tpg,
1618                                 struct scsiback_tpg, se_tpg);
1619         struct scsiback_tport *tport_wwn = tpg->tport;
1620         unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1621         int ret;
1622         /*
1623          * Shutdown the active I_T nexus if 'NULL' is passed.
1624          */
1625         if (!strncmp(page, "NULL", 4)) {
1626                 ret = scsiback_drop_nexus(tpg);
1627                 return (!ret) ? count : ret;
1628         }
1629         /*
1630          * Otherwise make sure the passed virtual Initiator port WWN matches
1631          * the fabric protocol_id set in scsiback_make_tport(), and call
1632          * scsiback_make_nexus().
1633          */
1634         if (strlen(page) >= VSCSI_NAMELEN) {
1635                 pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1636                         page, VSCSI_NAMELEN);
1637                 return -EINVAL;
1638         }
1639         snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1640
1641         ptr = strstr(i_port, "naa.");
1642         if (ptr) {
1643                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1644                         pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1645                                 i_port, scsiback_dump_proto_id(tport_wwn));
1646                         return -EINVAL;
1647                 }
1648                 port_ptr = &i_port[0];
1649                 goto check_newline;
1650         }
1651         ptr = strstr(i_port, "fc.");
1652         if (ptr) {
1653                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1654                         pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1655                                 i_port, scsiback_dump_proto_id(tport_wwn));
1656                         return -EINVAL;
1657                 }
1658                 port_ptr = &i_port[3]; /* Skip over "fc." */
1659                 goto check_newline;
1660         }
1661         ptr = strstr(i_port, "iqn.");
1662         if (ptr) {
1663                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1664                         pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1665                                 i_port, scsiback_dump_proto_id(tport_wwn));
1666                         return -EINVAL;
1667                 }
1668                 port_ptr = &i_port[0];
1669                 goto check_newline;
1670         }
1671         pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1672                 i_port);
1673         return -EINVAL;
1674         /*
1675          * Clear any trailing newline for the NAA WWN
1676          */
1677 check_newline:
1678         if (i_port[strlen(i_port) - 1] == '\n')
1679                 i_port[strlen(i_port) - 1] = '\0';
1680
1681         ret = scsiback_make_nexus(tpg, port_ptr);
1682         if (ret < 0)
1683                 return ret;
1684
1685         return count;
1686 }
1687
1688 CONFIGFS_ATTR(scsiback_tpg_, nexus);
1689
1690 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1691         &scsiback_tpg_attr_nexus,
1692         NULL,
1693 };
1694
1695 static ssize_t
1696 scsiback_wwn_version_show(struct config_item *item, char *page)
1697 {
1698         return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1699                 UTS_RELEASE"\n",
1700                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1701 }
1702
1703 CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1704
1705 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1706         &scsiback_wwn_attr_version,
1707         NULL,
1708 };
1709
1710 static char *scsiback_get_fabric_name(void)
1711 {
1712         return "xen-pvscsi";
1713 }
1714
1715 static int scsiback_port_link(struct se_portal_group *se_tpg,
1716                                struct se_lun *lun)
1717 {
1718         struct scsiback_tpg *tpg = container_of(se_tpg,
1719                                 struct scsiback_tpg, se_tpg);
1720
1721         mutex_lock(&tpg->tv_tpg_mutex);
1722         tpg->tv_tpg_port_count++;
1723         mutex_unlock(&tpg->tv_tpg_mutex);
1724
1725         return 0;
1726 }
1727
1728 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1729                                   struct se_lun *lun)
1730 {
1731         struct scsiback_tpg *tpg = container_of(se_tpg,
1732                                 struct scsiback_tpg, se_tpg);
1733
1734         mutex_lock(&tpg->tv_tpg_mutex);
1735         tpg->tv_tpg_port_count--;
1736         mutex_unlock(&tpg->tv_tpg_mutex);
1737 }
1738
1739 static struct se_portal_group *
1740 scsiback_make_tpg(struct se_wwn *wwn,
1741                    struct config_group *group,
1742                    const char *name)
1743 {
1744         struct scsiback_tport *tport = container_of(wwn,
1745                         struct scsiback_tport, tport_wwn);
1746
1747         struct scsiback_tpg *tpg;
1748         u16 tpgt;
1749         int ret;
1750
1751         if (strstr(name, "tpgt_") != name)
1752                 return ERR_PTR(-EINVAL);
1753         ret = kstrtou16(name + 5, 10, &tpgt);
1754         if (ret)
1755                 return ERR_PTR(ret);
1756
1757         tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1758         if (!tpg)
1759                 return ERR_PTR(-ENOMEM);
1760
1761         mutex_init(&tpg->tv_tpg_mutex);
1762         INIT_LIST_HEAD(&tpg->tv_tpg_list);
1763         INIT_LIST_HEAD(&tpg->info_list);
1764         tpg->tport = tport;
1765         tpg->tport_tpgt = tpgt;
1766
1767         ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1768         if (ret < 0) {
1769                 kfree(tpg);
1770                 return NULL;
1771         }
1772         mutex_lock(&scsiback_mutex);
1773         list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1774         mutex_unlock(&scsiback_mutex);
1775
1776         return &tpg->se_tpg;
1777 }
1778
1779 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1780 {
1781         struct scsiback_tpg *tpg = container_of(se_tpg,
1782                                 struct scsiback_tpg, se_tpg);
1783
1784         mutex_lock(&scsiback_mutex);
1785         list_del(&tpg->tv_tpg_list);
1786         mutex_unlock(&scsiback_mutex);
1787         /*
1788          * Release the virtual I_T Nexus for this xen-pvscsi TPG
1789          */
1790         scsiback_drop_nexus(tpg);
1791         /*
1792          * Deregister the se_tpg from TCM.
1793          */
1794         core_tpg_deregister(se_tpg);
1795         kfree(tpg);
1796 }
1797
1798 static int scsiback_check_true(struct se_portal_group *se_tpg)
1799 {
1800         return 1;
1801 }
1802
1803 static int scsiback_check_false(struct se_portal_group *se_tpg)
1804 {
1805         return 0;
1806 }
1807
1808 static const struct target_core_fabric_ops scsiback_ops = {
1809         .module                         = THIS_MODULE,
1810         .name                           = "xen-pvscsi",
1811         .get_fabric_name                = scsiback_get_fabric_name,
1812         .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1813         .tpg_get_tag                    = scsiback_get_tag,
1814         .tpg_check_demo_mode            = scsiback_check_true,
1815         .tpg_check_demo_mode_cache      = scsiback_check_true,
1816         .tpg_check_demo_mode_write_protect = scsiback_check_false,
1817         .tpg_check_prod_mode_write_protect = scsiback_check_false,
1818         .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1819         .check_stop_free                = scsiback_check_stop_free,
1820         .release_cmd                    = scsiback_release_cmd,
1821         .shutdown_session               = scsiback_shutdown_session,
1822         .close_session                  = scsiback_close_session,
1823         .sess_get_index                 = scsiback_sess_get_index,
1824         .sess_get_initiator_sid         = NULL,
1825         .write_pending                  = scsiback_write_pending,
1826         .write_pending_status           = scsiback_write_pending_status,
1827         .set_default_node_attributes    = scsiback_set_default_node_attrs,
1828         .get_cmd_state                  = scsiback_get_cmd_state,
1829         .queue_data_in                  = scsiback_queue_data_in,
1830         .queue_status                   = scsiback_queue_status,
1831         .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1832         .aborted_task                   = scsiback_aborted_task,
1833         /*
1834          * Setup callers for generic logic in target_core_fabric_configfs.c
1835          */
1836         .fabric_make_wwn                = scsiback_make_tport,
1837         .fabric_drop_wwn                = scsiback_drop_tport,
1838         .fabric_make_tpg                = scsiback_make_tpg,
1839         .fabric_drop_tpg                = scsiback_drop_tpg,
1840         .fabric_post_link               = scsiback_port_link,
1841         .fabric_pre_unlink              = scsiback_port_unlink,
1842
1843         .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1844         .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1845         .tfc_tpg_param_attrs            = scsiback_param_attrs,
1846 };
1847
1848 static const struct xenbus_device_id scsiback_ids[] = {
1849         { "vscsi" },
1850         { "" }
1851 };
1852
1853 static struct xenbus_driver scsiback_driver = {
1854         .ids                    = scsiback_ids,
1855         .probe                  = scsiback_probe,
1856         .remove                 = scsiback_remove,
1857         .otherend_changed       = scsiback_frontend_changed
1858 };
1859
1860 static void scsiback_init_pend(void *p)
1861 {
1862         struct vscsibk_pend *pend = p;
1863         int i;
1864
1865         memset(pend, 0, sizeof(*pend));
1866         for (i = 0; i < VSCSI_MAX_GRANTS; i++)
1867                 pend->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
1868 }
1869
1870 static int __init scsiback_init(void)
1871 {
1872         int ret;
1873
1874         if (!xen_domain())
1875                 return -ENODEV;
1876
1877         pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1878                  VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1879
1880         scsiback_cachep = kmem_cache_create("vscsiif_cache",
1881                 sizeof(struct vscsibk_pend), 0, 0, scsiback_init_pend);
1882         if (!scsiback_cachep)
1883                 return -ENOMEM;
1884
1885         ret = xenbus_register_backend(&scsiback_driver);
1886         if (ret)
1887                 goto out_cache_destroy;
1888
1889         ret = target_register_template(&scsiback_ops);
1890         if (ret)
1891                 goto out_unregister_xenbus;
1892
1893         return 0;
1894
1895 out_unregister_xenbus:
1896         xenbus_unregister_driver(&scsiback_driver);
1897 out_cache_destroy:
1898         kmem_cache_destroy(scsiback_cachep);
1899         pr_err("%s: error %d\n", __func__, ret);
1900         return ret;
1901 }
1902
1903 static void __exit scsiback_exit(void)
1904 {
1905         struct page *page;
1906
1907         while (free_pages_num) {
1908                 if (get_free_page(&page))
1909                         BUG();
1910                 gnttab_free_pages(1, &page);
1911         }
1912         target_unregister_template(&scsiback_ops);
1913         xenbus_unregister_driver(&scsiback_driver);
1914         kmem_cache_destroy(scsiback_cachep);
1915 }
1916
1917 module_init(scsiback_init);
1918 module_exit(scsiback_exit);
1919
1920 MODULE_DESCRIPTION("Xen SCSI backend driver");
1921 MODULE_LICENSE("Dual BSD/GPL");
1922 MODULE_ALIAS("xen-backend:vscsi");
1923 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");