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 <linux/module.h>
  37 #include <linux/utsname.h>
  38 #include <linux/interrupt.h>
  39 #include <linux/slab.h>
  40 #include <linux/wait.h>
  41 #include <linux/sched.h>
  42 #include <linux/list.h>
  43 #include <linux/gfp.h>
  44 #include <linux/delay.h>
  45 #include <linux/spinlock.h>
  46 #include <linux/configfs.h>
  47
  48 #include <generated/utsrelease.h>
  49
  50 #include <scsi/scsi_host.h> /* SG_ALL */
  51
  52 #include <target/target_core_base.h>
  53 #include <target/target_core_fabric.h>
  54
  55 #include <asm/hypervisor.h>
  56
  57 #include <xen/xen.h>
  58 #include <xen/balloon.h>
  59 #include <xen/events.h>
  60 #include <xen/xenbus.h>
  61 #include <xen/grant_table.h>
  62 #include <xen/page.h>
  63
  64 #include <xen/interface/grant_table.h>
  65 #include <xen/interface/io/vscsiif.h>
  66
  67 #define VSCSI_VERSION   "v0.1"
  68 #define VSCSI_NAMELEN   32
  69
  70 struct ids_tuple {
  71         unsigned int hst;               /* host    */
  72         unsigned int chn;               /* channel */
  73         unsigned int tgt;               /* target  */
  74         unsigned int lun;               /* LUN     */
  75 };
  76
  77 struct v2p_entry {
  78         struct ids_tuple v;             /* translate from */
  79         struct scsiback_tpg *tpg;       /* translate to   */
  80         unsigned int lun;
  81         struct kref kref;
  82         struct list_head l;
  83 };
  84
  85 struct vscsibk_info {
  86         struct xenbus_device *dev;
  87
  88         domid_t domid;
  89         unsigned int irq;
  90
  91         struct vscsiif_back_ring ring;
  92
  93         spinlock_t ring_lock;
  94         atomic_t nr_unreplied_reqs;
  95
  96         spinlock_t v2p_lock;
  97         struct list_head v2p_entry_lists;
  98
  99         wait_queue_head_t waiting_to_free;
 100
 101         struct gnttab_page_cache free_pages;
 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         struct completion tmr_done;
 138 };
 139
 140 #define VSCSI_DEFAULT_SESSION_TAGS      128
 141
 142 struct scsiback_nexus {
 143         /* Pointer to TCM session for I_T Nexus */
 144         struct se_session *tvn_se_sess;
 145 };
 146
 147 struct scsiback_tport {
 148         /* SCSI protocol the tport is providing */
 149         u8 tport_proto_id;
 150         /* Binary World Wide unique Port Name for pvscsi Target port */
 151         u64 tport_wwpn;
 152         /* ASCII formatted WWPN for pvscsi Target port */
 153         char tport_name[VSCSI_NAMELEN];
 154         /* Returned by scsiback_make_tport() */
 155         struct se_wwn tport_wwn;
 156 };
 157
 158 struct scsiback_tpg {
 159         /* scsiback port target portal group tag for TCM */
 160         u16 tport_tpgt;
 161         /* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
 162         int tv_tpg_port_count;
 163         /* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
 164         int tv_tpg_fe_count;
 165         /* list for scsiback_list */
 166         struct list_head tv_tpg_list;
 167         /* Used to protect access for tpg_nexus */
 168         struct mutex tv_tpg_mutex;
 169         /* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
 170         struct scsiback_nexus *tpg_nexus;
 171         /* Pointer back to scsiback_tport */
 172         struct scsiback_tport *tport;
 173         /* Returned by scsiback_make_tpg() */
 174         struct se_portal_group se_tpg;
 175         /* alias used in xenstore */
 176         char param_alias[VSCSI_NAMELEN];
 177         /* list of info structures related to this target portal group */
 178         struct list_head info_list;
 179 };
 180
 181 #define SCSIBACK_INVALID_HANDLE (~0)
 182
 183 static bool log_print_stat;
 184 module_param(log_print_stat, bool, 0644);
 185
 186 static int scsiback_max_buffer_pages = 1024;
 187 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
 188 MODULE_PARM_DESC(max_buffer_pages,
 189 "Maximum number of free pages to keep in backend buffer");
 190
 191 /* Global spinlock to protect scsiback TPG list */
 192 static DEFINE_MUTEX(scsiback_mutex);
 193 static LIST_HEAD(scsiback_list);
 194
 195 static void scsiback_get(struct vscsibk_info *info)
 196 {
 197         atomic_inc(&info->nr_unreplied_reqs);
 198 }
 199
 200 static void scsiback_put(struct vscsibk_info *info)
 201 {
 202         if (atomic_dec_and_test(&info->nr_unreplied_reqs))
 203                 wake_up(&info->waiting_to_free);
 204 }
 205
 206 static unsigned long vaddr_page(struct page *page)
 207 {
 208         unsigned long pfn = page_to_pfn(page);
 209
 210         return (unsigned long)pfn_to_kaddr(pfn);
 211 }
 212
 213 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
 214 {
 215         return vaddr_page(req->pages[seg]);
 216 }
 217
 218 static void scsiback_print_status(char *sense_buffer, int errors,
 219                                         struct vscsibk_pend *pending_req)
 220 {
 221         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 222
 223         pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x\n",
 224                tpg->tport->tport_name, pending_req->v2p->lun,
 225                pending_req->cmnd[0], errors & 0xff, COMMAND_COMPLETE,
 226                host_byte(errors));
 227 }
 228
 229 static void scsiback_fast_flush_area(struct vscsibk_pend *req)
 230 {
 231         struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
 232         struct page *pages[VSCSI_GRANT_BATCH];
 233         unsigned int i, invcount = 0;
 234         grant_handle_t handle;
 235         int err;
 236
 237         kfree(req->sgl);
 238         req->sgl = NULL;
 239         req->n_sg = 0;
 240
 241         if (!req->n_grants)
 242                 return;
 243
 244         for (i = 0; i < req->n_grants; i++) {
 245                 handle = req->grant_handles[i];
 246                 if (handle == SCSIBACK_INVALID_HANDLE)
 247                         continue;
 248                 gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
 249                                     GNTMAP_host_map, handle);
 250                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 251                 pages[invcount] = req->pages[i];
 252                 put_page(pages[invcount]);
 253                 invcount++;
 254                 if (invcount < VSCSI_GRANT_BATCH)
 255                         continue;
 256                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 257                 BUG_ON(err);
 258                 invcount = 0;
 259         }
 260
 261         if (invcount) {
 262                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 263                 BUG_ON(err);
 264         }
 265
 266         gnttab_page_cache_put(&req->info->free_pages, req->pages,
 267                               req->n_grants);
 268         req->n_grants = 0;
 269 }
 270
 271 static void scsiback_free_translation_entry(struct kref *kref)
 272 {
 273         struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
 274         struct scsiback_tpg *tpg = entry->tpg;
 275
 276         mutex_lock(&tpg->tv_tpg_mutex);
 277         tpg->tv_tpg_fe_count--;
 278         mutex_unlock(&tpg->tv_tpg_mutex);
 279
 280         kfree(entry);
 281 }
 282
 283 static int32_t scsiback_result(int32_t result)
 284 {
 285         int32_t host_status;
 286
 287         switch (XEN_VSCSIIF_RSLT_HOST(result)) {
 288         case DID_OK:
 289                 host_status = XEN_VSCSIIF_RSLT_HOST_OK;
 290                 break;
 291         case DID_NO_CONNECT:
 292                 host_status = XEN_VSCSIIF_RSLT_HOST_NO_CONNECT;
 293                 break;
 294         case DID_BUS_BUSY:
 295                 host_status = XEN_VSCSIIF_RSLT_HOST_BUS_BUSY;
 296                 break;
 297         case DID_TIME_OUT:
 298                 host_status = XEN_VSCSIIF_RSLT_HOST_TIME_OUT;
 299                 break;
 300         case DID_BAD_TARGET:
 301                 host_status = XEN_VSCSIIF_RSLT_HOST_BAD_TARGET;
 302                 break;
 303         case DID_ABORT:
 304                 host_status = XEN_VSCSIIF_RSLT_HOST_ABORT;
 305                 break;
 306         case DID_PARITY:
 307                 host_status = XEN_VSCSIIF_RSLT_HOST_PARITY;
 308                 break;
 309         case DID_ERROR:
 310                 host_status = XEN_VSCSIIF_RSLT_HOST_ERROR;
 311                 break;
 312         case DID_RESET:
 313                 host_status = XEN_VSCSIIF_RSLT_HOST_RESET;
 314                 break;
 315         case DID_BAD_INTR:
 316                 host_status = XEN_VSCSIIF_RSLT_HOST_BAD_INTR;
 317                 break;
 318         case DID_PASSTHROUGH:
 319                 host_status = XEN_VSCSIIF_RSLT_HOST_PASSTHROUGH;
 320                 break;
 321         case DID_SOFT_ERROR:
 322                 host_status = XEN_VSCSIIF_RSLT_HOST_SOFT_ERROR;
 323                 break;
 324         case DID_IMM_RETRY:
 325                 host_status = XEN_VSCSIIF_RSLT_HOST_IMM_RETRY;
 326                 break;
 327         case DID_REQUEUE:
 328                 host_status = XEN_VSCSIIF_RSLT_HOST_REQUEUE;
 329                 break;
 330         case DID_TRANSPORT_DISRUPTED:
 331                 host_status = XEN_VSCSIIF_RSLT_HOST_TRANSPORT_DISRUPTED;
 332                 break;
 333         case DID_TRANSPORT_FAILFAST:
 334                 host_status = XEN_VSCSIIF_RSLT_HOST_TRANSPORT_FAILFAST;
 335                 break;
 336         case DID_TRANSPORT_MARGINAL:
 337                 host_status = XEN_VSCSIIF_RSLT_HOST_TRANSPORT_MARGINAL;
 338                 break;
 339         default:
 340                 host_status = XEN_VSCSIIF_RSLT_HOST_ERROR;
 341                 break;
 342         }
 343
 344         return (host_status << 16) | (result & 0x00ffff);
 345 }
 346
 347 static void scsiback_send_response(struct vscsibk_info *info,
 348                         char *sense_buffer, int32_t result, uint32_t resid,
 349                         uint16_t rqid)
 350 {
 351         struct vscsiif_response *ring_res;
 352         int notify;
 353         struct scsi_sense_hdr sshdr;
 354         unsigned long flags;
 355         unsigned len;
 356
 357         spin_lock_irqsave(&info->ring_lock, flags);
 358
 359         ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
 360         info->ring.rsp_prod_pvt++;
 361
 362         ring_res->rslt   = scsiback_result(result);
 363         ring_res->rqid   = rqid;
 364
 365         if (sense_buffer != NULL &&
 366             scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
 367                                  &sshdr)) {
 368                 len = min_t(unsigned, 8 + sense_buffer[7],
 369                             VSCSIIF_SENSE_BUFFERSIZE);
 370                 memcpy(ring_res->sense_buffer, sense_buffer, len);
 371                 ring_res->sense_len = len;
 372         } else {
 373                 ring_res->sense_len = 0;
 374         }
 375
 376         ring_res->residual_len = resid;
 377
 378         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
 379         spin_unlock_irqrestore(&info->ring_lock, flags);
 380
 381         if (notify)
 382                 notify_remote_via_irq(info->irq);
 383 }
 384
 385 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
 386                         uint32_t resid, struct vscsibk_pend *pending_req)
 387 {
 388         scsiback_send_response(pending_req->info, sense_buffer, result,
 389                                resid, pending_req->rqid);
 390
 391         if (pending_req->v2p)
 392                 kref_put(&pending_req->v2p->kref,
 393                          scsiback_free_translation_entry);
 394 }
 395
 396 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
 397 {
 398         struct vscsibk_info *info = pending_req->info;
 399         unsigned char *sense_buffer;
 400         unsigned int resid;
 401         int errors;
 402
 403         sense_buffer = pending_req->sense_buffer;
 404         resid        = pending_req->se_cmd.residual_count;
 405         errors       = pending_req->result;
 406
 407         if (errors && log_print_stat)
 408                 scsiback_print_status(sense_buffer, errors, pending_req);
 409
 410         scsiback_fast_flush_area(pending_req);
 411         scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
 412         scsiback_put(info);
 413         /*
 414          * Drop the extra KREF_ACK reference taken by target_submit_cmd_map_sgls()
 415          * ahead of scsiback_check_stop_free() ->  transport_generic_free_cmd()
 416          * final se_cmd->cmd_kref put.
 417          */
 418         target_put_sess_cmd(&pending_req->se_cmd);
 419 }
 420
 421 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
 422 {
 423         struct se_cmd *se_cmd = &pending_req->se_cmd;
 424         struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
 425
 426         scsiback_get(pending_req->info);
 427         se_cmd->tag = pending_req->rqid;
 428         target_init_cmd(se_cmd, sess, pending_req->sense_buffer,
 429                         pending_req->v2p->lun, pending_req->data_len, 0,
 430                         pending_req->sc_data_direction, TARGET_SCF_ACK_KREF);
 431
 432         if (target_submit_prep(se_cmd, pending_req->cmnd, pending_req->sgl,
 433                                pending_req->n_sg, NULL, 0, NULL, 0, GFP_KERNEL))
 434                 return;
 435
 436         target_submit(se_cmd);
 437 }
 438
 439 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 440         struct page **pg, grant_handle_t *grant, int cnt)
 441 {
 442         int err, i;
 443
 444         if (!cnt)
 445                 return 0;
 446
 447         err = gnttab_map_refs(map, NULL, pg, cnt);
 448         for (i = 0; i < cnt; i++) {
 449                 if (unlikely(map[i].status != GNTST_okay)) {
 450                         pr_err("invalid buffer -- could not remap it\n");
 451                         map[i].handle = SCSIBACK_INVALID_HANDLE;
 452                         if (!err)
 453                                 err = -ENOMEM;
 454                 } else {
 455                         get_page(pg[i]);
 456                 }
 457                 grant[i] = map[i].handle;
 458         }
 459         return err;
 460 }
 461
 462 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
 463                         struct scsiif_request_segment *seg, struct page **pg,
 464                         grant_handle_t *grant, int cnt, u32 flags)
 465 {
 466         int mapcount = 0, i, err = 0;
 467         struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
 468         struct vscsibk_info *info = pending_req->info;
 469
 470         for (i = 0; i < cnt; i++) {
 471                 if (gnttab_page_cache_get(&info->free_pages, pg + mapcount)) {
 472                         gnttab_page_cache_put(&info->free_pages, pg, mapcount);
 473                         pr_err("no grant page\n");
 474                         return -ENOMEM;
 475                 }
 476                 gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
 477                                   flags, seg[i].gref, info->domid);
 478                 mapcount++;
 479                 if (mapcount < VSCSI_GRANT_BATCH)
 480                         continue;
 481                 err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 482                 pg += mapcount;
 483                 grant += mapcount;
 484                 pending_req->n_grants += mapcount;
 485                 if (err)
 486                         return err;
 487                 mapcount = 0;
 488         }
 489         err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 490         pending_req->n_grants += mapcount;
 491         return err;
 492 }
 493
 494 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 495                                         struct vscsibk_pend *pending_req)
 496 {
 497         u32 flags;
 498         int i, err, n_segs, i_seg = 0;
 499         struct page **pg;
 500         struct scsiif_request_segment *seg;
 501         unsigned long end_seg = 0;
 502         unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
 503         unsigned int nr_sgl = 0;
 504         struct scatterlist *sg;
 505         grant_handle_t *grant;
 506
 507         pending_req->n_sg = 0;
 508         pending_req->n_grants = 0;
 509         pending_req->data_len = 0;
 510
 511         nr_segments &= ~VSCSIIF_SG_GRANT;
 512         if (!nr_segments)
 513                 return 0;
 514
 515         if (nr_segments > VSCSIIF_SG_TABLESIZE) {
 516                 pr_debug("invalid parameter nr_seg = %d\n",
 517                         ring_req->nr_segments);
 518                 return -EINVAL;
 519         }
 520
 521         if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
 522                 err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
 523                         pending_req->pages, pending_req->grant_handles,
 524                         nr_segments, GNTMAP_host_map | GNTMAP_readonly);
 525                 if (err)
 526                         return err;
 527                 nr_sgl = nr_segments;
 528                 nr_segments = 0;
 529                 for (i = 0; i < nr_sgl; i++) {
 530                         n_segs = ring_req->seg[i].length /
 531                                  sizeof(struct scsiif_request_segment);
 532                         if ((unsigned)ring_req->seg[i].offset +
 533                             (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
 534                             n_segs * sizeof(struct scsiif_request_segment) !=
 535                             ring_req->seg[i].length)
 536                                 return -EINVAL;
 537                         nr_segments += n_segs;
 538                 }
 539                 if (nr_segments > SG_ALL) {
 540                         pr_debug("invalid nr_seg = %d\n", nr_segments);
 541                         return -EINVAL;
 542                 }
 543         }
 544
 545         /* free of (sgl) in fast_flush_area() */
 546         pending_req->sgl = kmalloc_array(nr_segments,
 547                                         sizeof(struct scatterlist), GFP_KERNEL);
 548         if (!pending_req->sgl)
 549                 return -ENOMEM;
 550
 551         sg_init_table(pending_req->sgl, nr_segments);
 552         pending_req->n_sg = nr_segments;
 553
 554         flags = GNTMAP_host_map;
 555         if (pending_req->sc_data_direction == DMA_TO_DEVICE)
 556                 flags |= GNTMAP_readonly;
 557
 558         pg = pending_req->pages + nr_sgl;
 559         grant = pending_req->grant_handles + nr_sgl;
 560         if (!nr_sgl) {
 561                 seg = ring_req->seg;
 562                 err = scsiback_gnttab_data_map_list(pending_req, seg,
 563                         pg, grant, nr_segments, flags);
 564                 if (err)
 565                         return err;
 566         } else {
 567                 for (i = 0; i < nr_sgl; i++) {
 568                         seg = (struct scsiif_request_segment *)(
 569                               vaddr(pending_req, i) + ring_req->seg[i].offset);
 570                         n_segs = ring_req->seg[i].length /
 571                                  sizeof(struct scsiif_request_segment);
 572                         err = scsiback_gnttab_data_map_list(pending_req, seg,
 573                                 pg, grant, n_segs, flags);
 574                         if (err)
 575                                 return err;
 576                         pg += n_segs;
 577                         grant += n_segs;
 578                 }
 579                 end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
 580                 seg = (struct scsiif_request_segment *)end_seg;
 581                 end_seg += ring_req->seg[0].length;
 582                 pg = pending_req->pages + nr_sgl;
 583         }
 584
 585         for_each_sg(pending_req->sgl, sg, nr_segments, i) {
 586                 sg_set_page(sg, pg[i], seg->length, seg->offset);
 587                 pending_req->data_len += seg->length;
 588                 seg++;
 589                 if (nr_sgl && (unsigned long)seg >= end_seg) {
 590                         i_seg++;
 591                         end_seg = vaddr(pending_req, i_seg) +
 592                                   ring_req->seg[i_seg].offset;
 593                         seg = (struct scsiif_request_segment *)end_seg;
 594                         end_seg += ring_req->seg[i_seg].length;
 595                 }
 596                 if (sg->offset >= PAGE_SIZE ||
 597                     sg->length > PAGE_SIZE ||
 598                     sg->offset + sg->length > PAGE_SIZE)
 599                         return -EINVAL;
 600         }
 601
 602         return 0;
 603 }
 604
 605 static void scsiback_disconnect(struct vscsibk_info *info)
 606 {
 607         wait_event(info->waiting_to_free,
 608                 atomic_read(&info->nr_unreplied_reqs) == 0);
 609
 610         unbind_from_irqhandler(info->irq, info);
 611         info->irq = 0;
 612         xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
 613 }
 614
 615 static void scsiback_device_action(struct vscsibk_pend *pending_req,
 616         enum tcm_tmreq_table act, int tag)
 617 {
 618         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 619         struct scsiback_nexus *nexus = tpg->tpg_nexus;
 620         struct se_cmd *se_cmd = &pending_req->se_cmd;
 621         u64 unpacked_lun = pending_req->v2p->lun;
 622         int rc, err = XEN_VSCSIIF_RSLT_RESET_FAILED;
 623
 624         init_completion(&pending_req->tmr_done);
 625
 626         rc = target_submit_tmr(&pending_req->se_cmd, nexus->tvn_se_sess,
 627                                &pending_req->sense_buffer[0],
 628                                unpacked_lun, NULL, act, GFP_KERNEL,
 629                                tag, TARGET_SCF_ACK_KREF);
 630         if (rc)
 631                 goto err;
 632
 633         wait_for_completion(&pending_req->tmr_done);
 634
 635         err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
 636                 XEN_VSCSIIF_RSLT_RESET_SUCCESS : XEN_VSCSIIF_RSLT_RESET_FAILED;
 637
 638         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 639         transport_generic_free_cmd(&pending_req->se_cmd, 0);
 640         return;
 641
 642 err:
 643         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 644 }
 645
 646 /*
 647   Perform virtual to physical translation
 648 */
 649 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
 650                         struct ids_tuple *v)
 651 {
 652         struct v2p_entry *entry;
 653         struct list_head *head = &(info->v2p_entry_lists);
 654         unsigned long flags;
 655
 656         spin_lock_irqsave(&info->v2p_lock, flags);
 657         list_for_each_entry(entry, head, l) {
 658                 if ((entry->v.chn == v->chn) &&
 659                     (entry->v.tgt == v->tgt) &&
 660                     (entry->v.lun == v->lun)) {
 661                         kref_get(&entry->kref);
 662                         goto out;
 663                 }
 664         }
 665         entry = NULL;
 666
 667 out:
 668         spin_unlock_irqrestore(&info->v2p_lock, flags);
 669         return entry;
 670 }
 671
 672 static struct vscsibk_pend *scsiback_get_pend_req(struct vscsiif_back_ring *ring,
 673                                 struct v2p_entry *v2p)
 674 {
 675         struct scsiback_tpg *tpg = v2p->tpg;
 676         struct scsiback_nexus *nexus = tpg->tpg_nexus;
 677         struct se_session *se_sess = nexus->tvn_se_sess;
 678         struct vscsibk_pend *req;
 679         int tag, cpu, i;
 680
 681         tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
 682         if (tag < 0) {
 683                 pr_err("Unable to obtain tag for vscsiif_request\n");
 684                 return ERR_PTR(-ENOMEM);
 685         }
 686
 687         req = &((struct vscsibk_pend *)se_sess->sess_cmd_map)[tag];
 688         memset(req, 0, sizeof(*req));
 689         req->se_cmd.map_tag = tag;
 690         req->se_cmd.map_cpu = cpu;
 691
 692         for (i = 0; i < VSCSI_MAX_GRANTS; i++)
 693                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 694
 695         return req;
 696 }
 697
 698 static struct vscsibk_pend *prepare_pending_reqs(struct vscsibk_info *info,
 699                                 struct vscsiif_back_ring *ring,
 700                                 struct vscsiif_request *ring_req)
 701 {
 702         struct vscsibk_pend *pending_req;
 703         struct v2p_entry *v2p;
 704         struct ids_tuple vir;
 705
 706         /* request range check from frontend */
 707         if ((ring_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
 708                 (ring_req->sc_data_direction != DMA_TO_DEVICE) &&
 709                 (ring_req->sc_data_direction != DMA_FROM_DEVICE) &&
 710                 (ring_req->sc_data_direction != DMA_NONE)) {
 711                 pr_debug("invalid parameter data_dir = %d\n",
 712                         ring_req->sc_data_direction);
 713                 return ERR_PTR(-EINVAL);
 714         }
 715         if (ring_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
 716                 pr_debug("invalid parameter cmd_len = %d\n",
 717                         ring_req->cmd_len);
 718                 return ERR_PTR(-EINVAL);
 719         }
 720
 721         vir.chn = ring_req->channel;
 722         vir.tgt = ring_req->id;
 723         vir.lun = ring_req->lun;
 724
 725         v2p = scsiback_do_translation(info, &vir);
 726         if (!v2p) {
 727                 pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
 728                          vir.chn, vir.tgt, vir.lun);
 729                 return ERR_PTR(-ENODEV);
 730         }
 731
 732         pending_req = scsiback_get_pend_req(ring, v2p);
 733         if (IS_ERR(pending_req)) {
 734                 kref_put(&v2p->kref, scsiback_free_translation_entry);
 735                 return ERR_PTR(-ENOMEM);
 736         }
 737         pending_req->rqid = ring_req->rqid;
 738         pending_req->info = info;
 739         pending_req->v2p = v2p;
 740         pending_req->sc_data_direction = ring_req->sc_data_direction;
 741         pending_req->cmd_len = ring_req->cmd_len;
 742         memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
 743
 744         return pending_req;
 745 }
 746
 747 static int scsiback_do_cmd_fn(struct vscsibk_info *info,
 748                               unsigned int *eoi_flags)
 749 {
 750         struct vscsiif_back_ring *ring = &info->ring;
 751         struct vscsiif_request ring_req;
 752         struct vscsibk_pend *pending_req;
 753         RING_IDX rc, rp;
 754         int more_to_do;
 755         uint32_t result;
 756
 757         rc = ring->req_cons;
 758         rp = ring->sring->req_prod;
 759         rmb();  /* guest system is accessing ring, too */
 760
 761         if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
 762                 rc = ring->rsp_prod_pvt;
 763                 pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 764                            info->domid, rp, rc, rp - rc);
 765                 return -EINVAL;
 766         }
 767
 768         while ((rc != rp)) {
 769                 *eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS;
 770
 771                 if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
 772                         break;
 773
 774                 RING_COPY_REQUEST(ring, rc, &ring_req);
 775                 ring->req_cons = ++rc;
 776
 777                 pending_req = prepare_pending_reqs(info, ring, &ring_req);
 778                 if (IS_ERR(pending_req)) {
 779                         switch (PTR_ERR(pending_req)) {
 780                         case -ENODEV:
 781                                 result = DID_NO_CONNECT;
 782                                 break;
 783                         default:
 784                                 result = DID_ERROR;
 785                                 break;
 786                         }
 787                         scsiback_send_response(info, NULL, result << 16, 0,
 788                                                ring_req.rqid);
 789                         return 1;
 790                 }
 791
 792                 switch (ring_req.act) {
 793                 case VSCSIIF_ACT_SCSI_CDB:
 794                         if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
 795                                 scsiback_fast_flush_area(pending_req);
 796                                 scsiback_do_resp_with_sense(NULL,
 797                                                 DID_ERROR << 16, 0, pending_req);
 798                                 transport_generic_free_cmd(&pending_req->se_cmd, 0);
 799                         } else {
 800                                 scsiback_cmd_exec(pending_req);
 801                         }
 802                         break;
 803                 case VSCSIIF_ACT_SCSI_ABORT:
 804                         scsiback_device_action(pending_req, TMR_ABORT_TASK,
 805                                 ring_req.ref_rqid);
 806                         break;
 807                 case VSCSIIF_ACT_SCSI_RESET:
 808                         scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
 809                         break;
 810                 default:
 811                         pr_err_ratelimited("invalid request\n");
 812                         scsiback_do_resp_with_sense(NULL, DID_ERROR << 16, 0,
 813                                                     pending_req);
 814                         transport_generic_free_cmd(&pending_req->se_cmd, 0);
 815                         break;
 816                 }
 817
 818                 /* Yield point for this unbounded loop. */
 819                 cond_resched();
 820         }
 821
 822         gnttab_page_cache_shrink(&info->free_pages, scsiback_max_buffer_pages);
 823
 824         RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
 825         return more_to_do;
 826 }
 827
 828 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
 829 {
 830         struct vscsibk_info *info = dev_id;
 831         int rc;
 832         unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
 833
 834         while ((rc = scsiback_do_cmd_fn(info, &eoi_flags)) > 0)
 835                 cond_resched();
 836
 837         /* In case of a ring error we keep the event channel masked. */
 838         if (!rc)
 839                 xen_irq_lateeoi(irq, eoi_flags);
 840
 841         return IRQ_HANDLED;
 842 }
 843
 844 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 845                         evtchn_port_t evtchn)
 846 {
 847         void *area;
 848         struct vscsiif_sring *sring;
 849         int err;
 850
 851         if (info->irq)
 852                 return -1;
 853
 854         err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 855         if (err)
 856                 return err;
 857
 858         sring = (struct vscsiif_sring *)area;
 859         BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 860
 861         err = bind_interdomain_evtchn_to_irq_lateeoi(info->dev, evtchn);
 862         if (err < 0)
 863                 goto unmap_page;
 864
 865         info->irq = err;
 866
 867         err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
 868                                    IRQF_ONESHOT, "vscsiif-backend", info);
 869         if (err)
 870                 goto free_irq;
 871
 872         return 0;
 873
 874 free_irq:
 875         unbind_from_irqhandler(info->irq, info);
 876         info->irq = 0;
 877 unmap_page:
 878         xenbus_unmap_ring_vfree(info->dev, area);
 879
 880         return err;
 881 }
 882
 883 static int scsiback_map(struct vscsibk_info *info)
 884 {
 885         struct xenbus_device *dev = info->dev;
 886         unsigned int ring_ref;
 887         evtchn_port_t evtchn;
 888         int err;
 889
 890         err = xenbus_gather(XBT_NIL, dev->otherend,
 891                         "ring-ref", "%u", &ring_ref,
 892                         "event-channel", "%u", &evtchn, NULL);
 893         if (err) {
 894                 xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
 895                 return err;
 896         }
 897
 898         return scsiback_init_sring(info, ring_ref, evtchn);
 899 }
 900
 901 /*
 902   Check for a translation entry being present
 903 */
 904 static struct v2p_entry *scsiback_chk_translation_entry(
 905         struct vscsibk_info *info, struct ids_tuple *v)
 906 {
 907         struct list_head *head = &(info->v2p_entry_lists);
 908         struct v2p_entry *entry;
 909
 910         list_for_each_entry(entry, head, l)
 911                 if ((entry->v.chn == v->chn) &&
 912                     (entry->v.tgt == v->tgt) &&
 913                     (entry->v.lun == v->lun))
 914                         return entry;
 915
 916         return NULL;
 917 }
 918
 919 /*
 920   Add a new translation entry
 921 */
 922 static int scsiback_add_translation_entry(struct vscsibk_info *info,
 923                                           char *phy, struct ids_tuple *v)
 924 {
 925         int err = 0;
 926         struct v2p_entry *new;
 927         unsigned long flags;
 928         char *lunp;
 929         unsigned long long unpacked_lun;
 930         struct se_lun *se_lun;
 931         struct scsiback_tpg *tpg_entry, *tpg = NULL;
 932         char *error = "doesn't exist";
 933
 934         lunp = strrchr(phy, ':');
 935         if (!lunp) {
 936                 pr_err("illegal format of physical device %s\n", phy);
 937                 return -EINVAL;
 938         }
 939         *lunp = 0;
 940         lunp++;
 941         err = kstrtoull(lunp, 10, &unpacked_lun);
 942         if (err < 0) {
 943                 pr_err("lun number not valid: %s\n", lunp);
 944                 return err;
 945         }
 946
 947         mutex_lock(&scsiback_mutex);
 948         list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
 949                 if (!strcmp(phy, tpg_entry->tport->tport_name) ||
 950                     !strcmp(phy, tpg_entry->param_alias)) {
 951                         mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
 952                         hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
 953                                 if (se_lun->unpacked_lun == unpacked_lun) {
 954                                         if (!tpg_entry->tpg_nexus)
 955                                                 error = "nexus undefined";
 956                                         else
 957                                                 tpg = tpg_entry;
 958                                         break;
 959                                 }
 960                         }
 961                         mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
 962                         break;
 963                 }
 964         }
 965         if (tpg) {
 966                 mutex_lock(&tpg->tv_tpg_mutex);
 967                 tpg->tv_tpg_fe_count++;
 968                 mutex_unlock(&tpg->tv_tpg_mutex);
 969         }
 970         mutex_unlock(&scsiback_mutex);
 971
 972         if (!tpg) {
 973                 pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
 974                 return -ENODEV;
 975         }
 976
 977         new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
 978         if (new == NULL) {
 979                 err = -ENOMEM;
 980                 goto out_free;
 981         }
 982
 983         spin_lock_irqsave(&info->v2p_lock, flags);
 984
 985         /* Check double assignment to identical virtual ID */
 986         if (scsiback_chk_translation_entry(info, v)) {
 987                 pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 988                 err = -EEXIST;
 989                 goto out;
 990         }
 991
 992         /* Create a new translation entry and add to the list */
 993         kref_init(&new->kref);
 994         new->v = *v;
 995         new->tpg = tpg;
 996         new->lun = unpacked_lun;
 997         list_add_tail(&new->l, &info->v2p_entry_lists);
 998
 999 out:
1000         spin_unlock_irqrestore(&info->v2p_lock, flags);
1001
1002 out_free:
1003         if (err) {
1004                 mutex_lock(&tpg->tv_tpg_mutex);
1005                 tpg->tv_tpg_fe_count--;
1006                 mutex_unlock(&tpg->tv_tpg_mutex);
1007                 kfree(new);
1008         }
1009
1010         return err;
1011 }
1012
1013 /*
1014   Delete the translation entry specified
1015 */
1016 static int scsiback_del_translation_entry(struct vscsibk_info *info,
1017                                           struct ids_tuple *v)
1018 {
1019         struct v2p_entry *entry;
1020         unsigned long flags;
1021
1022         spin_lock_irqsave(&info->v2p_lock, flags);
1023         /* Find out the translation entry specified */
1024         entry = scsiback_chk_translation_entry(info, v);
1025         if (entry)
1026                 list_del(&entry->l);
1027
1028         spin_unlock_irqrestore(&info->v2p_lock, flags);
1029
1030         if (!entry)
1031                 return -ENOENT;
1032
1033         kref_put(&entry->kref, scsiback_free_translation_entry);
1034         return 0;
1035 }
1036
1037 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
1038                                 char *phy, struct ids_tuple *vir, int try)
1039 {
1040         struct v2p_entry *entry;
1041         unsigned long flags;
1042         int err;
1043
1044         if (try) {
1045                 spin_lock_irqsave(&info->v2p_lock, flags);
1046                 entry = scsiback_chk_translation_entry(info, vir);
1047                 spin_unlock_irqrestore(&info->v2p_lock, flags);
1048                 if (entry)
1049                         return;
1050         }
1051         if (!scsiback_add_translation_entry(info, phy, vir)) {
1052                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1053                                   "%d", XenbusStateInitialised)) {
1054                         pr_err("xenbus_printf error %s\n", state);
1055                         scsiback_del_translation_entry(info, vir);
1056                 }
1057         } else if (!try) {
1058                 err = xenbus_printf(XBT_NIL, info->dev->nodename, state,
1059                               "%d", XenbusStateClosed);
1060                 if (err)
1061                         xenbus_dev_error(info->dev, err,
1062                                 "%s: writing %s", __func__, state);
1063         }
1064 }
1065
1066 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1067                                 struct ids_tuple *vir)
1068 {
1069         if (!scsiback_del_translation_entry(info, vir)) {
1070                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1071                                   "%d", XenbusStateClosed))
1072                         pr_err("xenbus_printf error %s\n", state);
1073         }
1074 }
1075
1076 #define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1077 #define VSCSIBACK_OP_UPDATEDEV_STATE    2
1078
1079 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1080                                      char *ent)
1081 {
1082         int err;
1083         struct ids_tuple vir;
1084         char *val;
1085         int device_state;
1086         char phy[VSCSI_NAMELEN];
1087         char str[64];
1088         char state[64];
1089         struct xenbus_device *dev = info->dev;
1090
1091         /* read status */
1092         snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1093         err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1094         if (XENBUS_EXIST_ERR(err))
1095                 return;
1096
1097         /* physical SCSI device */
1098         snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1099         val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1100         if (IS_ERR(val)) {
1101                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1102                               "%d", XenbusStateClosed);
1103                 if (err)
1104                         xenbus_dev_error(info->dev, err,
1105                                 "%s: writing %s", __func__, state);
1106                 return;
1107         }
1108         strscpy(phy, val, VSCSI_NAMELEN);
1109         kfree(val);
1110
1111         /* virtual SCSI device */
1112         snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1113         err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1114                            &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1115         if (XENBUS_EXIST_ERR(err)) {
1116                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1117                               "%d", XenbusStateClosed);
1118                 if (err)
1119                         xenbus_dev_error(info->dev, err,
1120                                 "%s: writing %s", __func__, state);
1121                 return;
1122         }
1123
1124         switch (op) {
1125         case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1126                 switch (device_state) {
1127                 case XenbusStateInitialising:
1128                         scsiback_do_add_lun(info, state, phy, &vir, 0);
1129                         break;
1130                 case XenbusStateConnected:
1131                         scsiback_do_add_lun(info, state, phy, &vir, 1);
1132                         break;
1133                 case XenbusStateClosing:
1134                         scsiback_do_del_lun(info, state, &vir);
1135                         break;
1136                 default:
1137                         break;
1138                 }
1139                 break;
1140
1141         case VSCSIBACK_OP_UPDATEDEV_STATE:
1142                 if (device_state == XenbusStateInitialised) {
1143                         /* modify vscsi-devs/dev-x/state */
1144                         if (xenbus_printf(XBT_NIL, dev->nodename, state,
1145                                           "%d", XenbusStateConnected)) {
1146                                 pr_err("xenbus_printf error %s\n", str);
1147                                 scsiback_del_translation_entry(info, &vir);
1148                                 xenbus_printf(XBT_NIL, dev->nodename, state,
1149                                               "%d", XenbusStateClosed);
1150                         }
1151                 }
1152                 break;
1153         /* When it is necessary, processing is added here. */
1154         default:
1155                 break;
1156         }
1157 }
1158
1159 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1160 {
1161         int i;
1162         char **dir;
1163         unsigned int ndir = 0;
1164
1165         dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1166                                &ndir);
1167         if (IS_ERR(dir))
1168                 return;
1169
1170         for (i = 0; i < ndir; i++)
1171                 scsiback_do_1lun_hotplug(info, op, dir[i]);
1172
1173         kfree(dir);
1174 }
1175
1176 static void scsiback_frontend_changed(struct xenbus_device *dev,
1177                                         enum xenbus_state frontend_state)
1178 {
1179         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1180
1181         switch (frontend_state) {
1182         case XenbusStateInitialising:
1183                 break;
1184
1185         case XenbusStateInitialised:
1186                 if (scsiback_map(info))
1187                         break;
1188
1189                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1190                 xenbus_switch_state(dev, XenbusStateConnected);
1191                 break;
1192
1193         case XenbusStateConnected:
1194                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1195
1196                 if (dev->state == XenbusStateConnected)
1197                         break;
1198
1199                 xenbus_switch_state(dev, XenbusStateConnected);
1200                 break;
1201
1202         case XenbusStateClosing:
1203                 if (info->irq)
1204                         scsiback_disconnect(info);
1205
1206                 xenbus_switch_state(dev, XenbusStateClosing);
1207                 break;
1208
1209         case XenbusStateClosed:
1210                 xenbus_switch_state(dev, XenbusStateClosed);
1211                 if (xenbus_dev_is_online(dev))
1212                         break;
1213                 fallthrough;    /* if not online */
1214         case XenbusStateUnknown:
1215                 device_unregister(&dev->dev);
1216                 break;
1217
1218         case XenbusStateReconfiguring:
1219                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1220                 xenbus_switch_state(dev, XenbusStateReconfigured);
1221
1222                 break;
1223
1224         default:
1225                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1226                                         frontend_state);
1227                 break;
1228         }
1229 }
1230
1231 /*
1232   Release the translation entry specfied
1233 */
1234 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1235 {
1236         struct v2p_entry *entry, *tmp;
1237         struct list_head *head = &(info->v2p_entry_lists);
1238         struct list_head tmp_list;
1239         unsigned long flags;
1240
1241         spin_lock_irqsave(&info->v2p_lock, flags);
1242
1243         list_cut_before(&tmp_list, head, head);
1244
1245         spin_unlock_irqrestore(&info->v2p_lock, flags);
1246
1247         list_for_each_entry_safe(entry, tmp, &tmp_list, l) {
1248                 list_del(&entry->l);
1249                 kref_put(&entry->kref, scsiback_free_translation_entry);
1250         }
1251 }
1252
1253 static void scsiback_remove(struct xenbus_device *dev)
1254 {
1255         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1256
1257         if (info->irq)
1258                 scsiback_disconnect(info);
1259
1260         scsiback_release_translation_entry(info);
1261
1262         gnttab_page_cache_shrink(&info->free_pages, 0);
1263
1264         dev_set_drvdata(&dev->dev, NULL);
1265 }
1266
1267 static int scsiback_probe(struct xenbus_device *dev,
1268                            const struct xenbus_device_id *id)
1269 {
1270         int err;
1271
1272         struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1273                                             GFP_KERNEL);
1274
1275         pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1276
1277         if (!info) {
1278                 xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1279                 return -ENOMEM;
1280         }
1281         info->dev = dev;
1282         dev_set_drvdata(&dev->dev, info);
1283
1284         info->domid = dev->otherend_id;
1285         spin_lock_init(&info->ring_lock);
1286         atomic_set(&info->nr_unreplied_reqs, 0);
1287         init_waitqueue_head(&info->waiting_to_free);
1288         info->dev = dev;
1289         info->irq = 0;
1290         INIT_LIST_HEAD(&info->v2p_entry_lists);
1291         spin_lock_init(&info->v2p_lock);
1292         gnttab_page_cache_init(&info->free_pages);
1293
1294         err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1295                             SG_ALL);
1296         if (err)
1297                 xenbus_dev_error(dev, err, "writing feature-sg-grant");
1298
1299         err = xenbus_switch_state(dev, XenbusStateInitWait);
1300         if (err)
1301                 goto fail;
1302
1303         return 0;
1304
1305 fail:
1306         pr_warn("%s failed\n", __func__);
1307         scsiback_remove(dev);
1308
1309         return err;
1310 }
1311
1312 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1313 {
1314         switch (tport->tport_proto_id) {
1315         case SCSI_PROTOCOL_SAS:
1316                 return "SAS";
1317         case SCSI_PROTOCOL_FCP:
1318                 return "FCP";
1319         case SCSI_PROTOCOL_ISCSI:
1320                 return "iSCSI";
1321         default:
1322                 break;
1323         }
1324
1325         return "Unknown";
1326 }
1327
1328 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1329 {
1330         struct scsiback_tpg *tpg = container_of(se_tpg,
1331                                 struct scsiback_tpg, se_tpg);
1332         struct scsiback_tport *tport = tpg->tport;
1333
1334         return &tport->tport_name[0];
1335 }
1336
1337 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1338 {
1339         struct scsiback_tpg *tpg = container_of(se_tpg,
1340                                 struct scsiback_tpg, se_tpg);
1341         return tpg->tport_tpgt;
1342 }
1343
1344 static struct se_wwn *
1345 scsiback_make_tport(struct target_fabric_configfs *tf,
1346                      struct config_group *group,
1347                      const char *name)
1348 {
1349         struct scsiback_tport *tport;
1350         char *ptr;
1351         u64 wwpn = 0;
1352         int off = 0;
1353
1354         tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1355         if (!tport)
1356                 return ERR_PTR(-ENOMEM);
1357
1358         tport->tport_wwpn = wwpn;
1359         /*
1360          * Determine the emulated Protocol Identifier and Target Port Name
1361          * based on the incoming configfs directory name.
1362          */
1363         ptr = strstr(name, "naa.");
1364         if (ptr) {
1365                 tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1366                 goto check_len;
1367         }
1368         ptr = strstr(name, "fc.");
1369         if (ptr) {
1370                 tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1371                 off = 3; /* Skip over "fc." */
1372                 goto check_len;
1373         }
1374         ptr = strstr(name, "iqn.");
1375         if (ptr) {
1376                 tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1377                 goto check_len;
1378         }
1379
1380         pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1381         kfree(tport);
1382         return ERR_PTR(-EINVAL);
1383
1384 check_len:
1385         if (strlen(name) >= VSCSI_NAMELEN) {
1386                 pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1387                         scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1388                 kfree(tport);
1389                 return ERR_PTR(-EINVAL);
1390         }
1391         snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1392
1393         pr_debug("Allocated emulated Target %s Address: %s\n",
1394                  scsiback_dump_proto_id(tport), name);
1395
1396         return &tport->tport_wwn;
1397 }
1398
1399 static void scsiback_drop_tport(struct se_wwn *wwn)
1400 {
1401         struct scsiback_tport *tport = container_of(wwn,
1402                                 struct scsiback_tport, tport_wwn);
1403
1404         pr_debug("Deallocating emulated Target %s Address: %s\n",
1405                  scsiback_dump_proto_id(tport), tport->tport_name);
1406
1407         kfree(tport);
1408 }
1409
1410 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1411 {
1412         return transport_generic_free_cmd(se_cmd, 0);
1413 }
1414
1415 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1416 {
1417         target_free_tag(se_cmd->se_sess, se_cmd);
1418 }
1419
1420 static int scsiback_write_pending(struct se_cmd *se_cmd)
1421 {
1422         /* Go ahead and process the write immediately */
1423         target_execute_cmd(se_cmd);
1424
1425         return 0;
1426 }
1427
1428 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1429 {
1430         struct vscsibk_pend *pending_req = container_of(se_cmd,
1431                                 struct vscsibk_pend, se_cmd);
1432
1433         pending_req->result = SAM_STAT_GOOD;
1434         scsiback_cmd_done(pending_req);
1435         return 0;
1436 }
1437
1438 static int scsiback_queue_status(struct se_cmd *se_cmd)
1439 {
1440         struct vscsibk_pend *pending_req = container_of(se_cmd,
1441                                 struct vscsibk_pend, se_cmd);
1442
1443         if (se_cmd->sense_buffer &&
1444             ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1445              (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1446                 pending_req->result = SAM_STAT_CHECK_CONDITION;
1447         else
1448                 pending_req->result = se_cmd->scsi_status;
1449
1450         scsiback_cmd_done(pending_req);
1451         return 0;
1452 }
1453
1454 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1455 {
1456         struct vscsibk_pend *pending_req = container_of(se_cmd,
1457                                 struct vscsibk_pend, se_cmd);
1458
1459         complete(&pending_req->tmr_done);
1460 }
1461
1462 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1463 {
1464 }
1465
1466 static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1467                                              char *page)
1468 {
1469         struct se_portal_group *se_tpg = param_to_tpg(item);
1470         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1471                                                 se_tpg);
1472         ssize_t rb;
1473
1474         mutex_lock(&tpg->tv_tpg_mutex);
1475         rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1476         mutex_unlock(&tpg->tv_tpg_mutex);
1477
1478         return rb;
1479 }
1480
1481 static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1482                                               const char *page, size_t count)
1483 {
1484         struct se_portal_group *se_tpg = param_to_tpg(item);
1485         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1486                                                 se_tpg);
1487         int len;
1488
1489         if (strlen(page) >= VSCSI_NAMELEN) {
1490                 pr_err("param alias: %s, exceeds max: %d\n", page,
1491                         VSCSI_NAMELEN);
1492                 return -EINVAL;
1493         }
1494
1495         mutex_lock(&tpg->tv_tpg_mutex);
1496         len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1497         if (tpg->param_alias[len - 1] == '\n')
1498                 tpg->param_alias[len - 1] = '\0';
1499         mutex_unlock(&tpg->tv_tpg_mutex);
1500
1501         return count;
1502 }
1503
1504 CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1505
1506 static struct configfs_attribute *scsiback_param_attrs[] = {
1507         &scsiback_tpg_param_attr_alias,
1508         NULL,
1509 };
1510
1511 static int scsiback_alloc_sess_cb(struct se_portal_group *se_tpg,
1512                                   struct se_session *se_sess, void *p)
1513 {
1514         struct scsiback_tpg *tpg = container_of(se_tpg,
1515                                 struct scsiback_tpg, se_tpg);
1516
1517         tpg->tpg_nexus = p;
1518         return 0;
1519 }
1520
1521 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1522                                 const char *name)
1523 {
1524         struct scsiback_nexus *tv_nexus;
1525         int ret = 0;
1526
1527         mutex_lock(&tpg->tv_tpg_mutex);
1528         if (tpg->tpg_nexus) {
1529                 pr_debug("tpg->tpg_nexus already exists\n");
1530                 ret = -EEXIST;
1531                 goto out_unlock;
1532         }
1533
1534         tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1535         if (!tv_nexus) {
1536                 ret = -ENOMEM;
1537                 goto out_unlock;
1538         }
1539
1540         tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg,
1541                                                      VSCSI_DEFAULT_SESSION_TAGS,
1542                                                      sizeof(struct vscsibk_pend),
1543                                                      TARGET_PROT_NORMAL, name,
1544                                                      tv_nexus, scsiback_alloc_sess_cb);
1545         if (IS_ERR(tv_nexus->tvn_se_sess)) {
1546                 kfree(tv_nexus);
1547                 ret = -ENOMEM;
1548                 goto out_unlock;
1549         }
1550
1551 out_unlock:
1552         mutex_unlock(&tpg->tv_tpg_mutex);
1553         return ret;
1554 }
1555
1556 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1557 {
1558         struct se_session *se_sess;
1559         struct scsiback_nexus *tv_nexus;
1560
1561         mutex_lock(&tpg->tv_tpg_mutex);
1562         tv_nexus = tpg->tpg_nexus;
1563         if (!tv_nexus) {
1564                 mutex_unlock(&tpg->tv_tpg_mutex);
1565                 return -ENODEV;
1566         }
1567
1568         se_sess = tv_nexus->tvn_se_sess;
1569         if (!se_sess) {
1570                 mutex_unlock(&tpg->tv_tpg_mutex);
1571                 return -ENODEV;
1572         }
1573
1574         if (tpg->tv_tpg_port_count != 0) {
1575                 mutex_unlock(&tpg->tv_tpg_mutex);
1576                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1577                         tpg->tv_tpg_port_count);
1578                 return -EBUSY;
1579         }
1580
1581         if (tpg->tv_tpg_fe_count != 0) {
1582                 mutex_unlock(&tpg->tv_tpg_mutex);
1583                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1584                         tpg->tv_tpg_fe_count);
1585                 return -EBUSY;
1586         }
1587
1588         pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1589                 scsiback_dump_proto_id(tpg->tport),
1590                 tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1591
1592         /*
1593          * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1594          */
1595         target_remove_session(se_sess);
1596         tpg->tpg_nexus = NULL;
1597         mutex_unlock(&tpg->tv_tpg_mutex);
1598
1599         kfree(tv_nexus);
1600         return 0;
1601 }
1602
1603 static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1604 {
1605         struct se_portal_group *se_tpg = to_tpg(item);
1606         struct scsiback_tpg *tpg = container_of(se_tpg,
1607                                 struct scsiback_tpg, se_tpg);
1608         struct scsiback_nexus *tv_nexus;
1609         ssize_t ret;
1610
1611         mutex_lock(&tpg->tv_tpg_mutex);
1612         tv_nexus = tpg->tpg_nexus;
1613         if (!tv_nexus) {
1614                 mutex_unlock(&tpg->tv_tpg_mutex);
1615                 return -ENODEV;
1616         }
1617         ret = snprintf(page, PAGE_SIZE, "%s\n",
1618                         tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1619         mutex_unlock(&tpg->tv_tpg_mutex);
1620
1621         return ret;
1622 }
1623
1624 static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
1625                 const char *page, size_t count)
1626 {
1627         struct se_portal_group *se_tpg = to_tpg(item);
1628         struct scsiback_tpg *tpg = container_of(se_tpg,
1629                                 struct scsiback_tpg, se_tpg);
1630         struct scsiback_tport *tport_wwn = tpg->tport;
1631         unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1632         int ret;
1633         /*
1634          * Shutdown the active I_T nexus if 'NULL' is passed.
1635          */
1636         if (!strncmp(page, "NULL", 4)) {
1637                 ret = scsiback_drop_nexus(tpg);
1638                 return (!ret) ? count : ret;
1639         }
1640         /*
1641          * Otherwise make sure the passed virtual Initiator port WWN matches
1642          * the fabric protocol_id set in scsiback_make_tport(), and call
1643          * scsiback_make_nexus().
1644          */
1645         if (strlen(page) >= VSCSI_NAMELEN) {
1646                 pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1647                         page, VSCSI_NAMELEN);
1648                 return -EINVAL;
1649         }
1650         snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1651
1652         ptr = strstr(i_port, "naa.");
1653         if (ptr) {
1654                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1655                         pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1656                                 i_port, scsiback_dump_proto_id(tport_wwn));
1657                         return -EINVAL;
1658                 }
1659                 port_ptr = &i_port[0];
1660                 goto check_newline;
1661         }
1662         ptr = strstr(i_port, "fc.");
1663         if (ptr) {
1664                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1665                         pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1666                                 i_port, scsiback_dump_proto_id(tport_wwn));
1667                         return -EINVAL;
1668                 }
1669                 port_ptr = &i_port[3]; /* Skip over "fc." */
1670                 goto check_newline;
1671         }
1672         ptr = strstr(i_port, "iqn.");
1673         if (ptr) {
1674                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1675                         pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1676                                 i_port, scsiback_dump_proto_id(tport_wwn));
1677                         return -EINVAL;
1678                 }
1679                 port_ptr = &i_port[0];
1680                 goto check_newline;
1681         }
1682         pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1683                 i_port);
1684         return -EINVAL;
1685         /*
1686          * Clear any trailing newline for the NAA WWN
1687          */
1688 check_newline:
1689         if (i_port[strlen(i_port) - 1] == '\n')
1690                 i_port[strlen(i_port) - 1] = '\0';
1691
1692         ret = scsiback_make_nexus(tpg, port_ptr);
1693         if (ret < 0)
1694                 return ret;
1695
1696         return count;
1697 }
1698
1699 CONFIGFS_ATTR(scsiback_tpg_, nexus);
1700
1701 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1702         &scsiback_tpg_attr_nexus,
1703         NULL,
1704 };
1705
1706 static ssize_t
1707 scsiback_wwn_version_show(struct config_item *item, char *page)
1708 {
1709         return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1710                 UTS_RELEASE"\n",
1711                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1712 }
1713
1714 CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1715
1716 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1717         &scsiback_wwn_attr_version,
1718         NULL,
1719 };
1720
1721 static int scsiback_port_link(struct se_portal_group *se_tpg,
1722                                struct se_lun *lun)
1723 {
1724         struct scsiback_tpg *tpg = container_of(se_tpg,
1725                                 struct scsiback_tpg, se_tpg);
1726
1727         mutex_lock(&tpg->tv_tpg_mutex);
1728         tpg->tv_tpg_port_count++;
1729         mutex_unlock(&tpg->tv_tpg_mutex);
1730
1731         return 0;
1732 }
1733
1734 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1735                                   struct se_lun *lun)
1736 {
1737         struct scsiback_tpg *tpg = container_of(se_tpg,
1738                                 struct scsiback_tpg, se_tpg);
1739
1740         mutex_lock(&tpg->tv_tpg_mutex);
1741         tpg->tv_tpg_port_count--;
1742         mutex_unlock(&tpg->tv_tpg_mutex);
1743 }
1744
1745 static struct se_portal_group *
1746 scsiback_make_tpg(struct se_wwn *wwn, const char *name)
1747 {
1748         struct scsiback_tport *tport = container_of(wwn,
1749                         struct scsiback_tport, tport_wwn);
1750
1751         struct scsiback_tpg *tpg;
1752         u16 tpgt;
1753         int ret;
1754
1755         if (strstr(name, "tpgt_") != name)
1756                 return ERR_PTR(-EINVAL);
1757         ret = kstrtou16(name + 5, 10, &tpgt);
1758         if (ret)
1759                 return ERR_PTR(ret);
1760
1761         tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1762         if (!tpg)
1763                 return ERR_PTR(-ENOMEM);
1764
1765         mutex_init(&tpg->tv_tpg_mutex);
1766         INIT_LIST_HEAD(&tpg->tv_tpg_list);
1767         INIT_LIST_HEAD(&tpg->info_list);
1768         tpg->tport = tport;
1769         tpg->tport_tpgt = tpgt;
1770
1771         ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1772         if (ret < 0) {
1773                 kfree(tpg);
1774                 return NULL;
1775         }
1776         mutex_lock(&scsiback_mutex);
1777         list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1778         mutex_unlock(&scsiback_mutex);
1779
1780         return &tpg->se_tpg;
1781 }
1782
1783 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1784 {
1785         struct scsiback_tpg *tpg = container_of(se_tpg,
1786                                 struct scsiback_tpg, se_tpg);
1787
1788         mutex_lock(&scsiback_mutex);
1789         list_del(&tpg->tv_tpg_list);
1790         mutex_unlock(&scsiback_mutex);
1791         /*
1792          * Release the virtual I_T Nexus for this xen-pvscsi TPG
1793          */
1794         scsiback_drop_nexus(tpg);
1795         /*
1796          * Deregister the se_tpg from TCM.
1797          */
1798         core_tpg_deregister(se_tpg);
1799         kfree(tpg);
1800 }
1801
1802 static int scsiback_check_true(struct se_portal_group *se_tpg)
1803 {
1804         return 1;
1805 }
1806
1807 static const struct target_core_fabric_ops scsiback_ops = {
1808         .module                         = THIS_MODULE,
1809         .fabric_name                    = "xen-pvscsi",
1810         .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1811         .tpg_get_tag                    = scsiback_get_tag,
1812         .tpg_check_demo_mode            = scsiback_check_true,
1813         .tpg_check_demo_mode_cache      = scsiback_check_true,
1814         .check_stop_free                = scsiback_check_stop_free,
1815         .release_cmd                    = scsiback_release_cmd,
1816         .sess_get_initiator_sid         = NULL,
1817         .write_pending                  = scsiback_write_pending,
1818         .queue_data_in                  = scsiback_queue_data_in,
1819         .queue_status                   = scsiback_queue_status,
1820         .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1821         .aborted_task                   = scsiback_aborted_task,
1822         /*
1823          * Setup callers for generic logic in target_core_fabric_configfs.c
1824          */
1825         .fabric_make_wwn                = scsiback_make_tport,
1826         .fabric_drop_wwn                = scsiback_drop_tport,
1827         .fabric_make_tpg                = scsiback_make_tpg,
1828         .fabric_drop_tpg                = scsiback_drop_tpg,
1829         .fabric_post_link               = scsiback_port_link,
1830         .fabric_pre_unlink              = scsiback_port_unlink,
1831
1832         .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1833         .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1834         .tfc_tpg_param_attrs            = scsiback_param_attrs,
1835 };
1836
1837 static const struct xenbus_device_id scsiback_ids[] = {
1838         { "vscsi" },
1839         { "" }
1840 };
1841
1842 static struct xenbus_driver scsiback_driver = {
1843         .ids                    = scsiback_ids,
1844         .probe                  = scsiback_probe,
1845         .remove                 = scsiback_remove,
1846         .otherend_changed       = scsiback_frontend_changed
1847 };
1848
1849 static int __init scsiback_init(void)
1850 {
1851         int ret;
1852
1853         if (!xen_domain())
1854                 return -ENODEV;
1855
1856         pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1857                  VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1858
1859         ret = xenbus_register_backend(&scsiback_driver);
1860         if (ret)
1861                 goto out;
1862
1863         ret = target_register_template(&scsiback_ops);
1864         if (ret)
1865                 goto out_unregister_xenbus;
1866
1867         return 0;
1868
1869 out_unregister_xenbus:
1870         xenbus_unregister_driver(&scsiback_driver);
1871 out:
1872         pr_err("%s: error %d\n", __func__, ret);
1873         return ret;
1874 }
1875
1876 static void __exit scsiback_exit(void)
1877 {
1878         target_unregister_template(&scsiback_ops);
1879         xenbus_unregister_driver(&scsiback_driver);
1880 }
1881
1882 module_init(scsiback_init);
1883 module_exit(scsiback_exit);
1884
1885 MODULE_DESCRIPTION("Xen SCSI backend driver");
1886 MODULE_LICENSE("Dual BSD/GPL");
1887 MODULE_ALIAS("xen-backend:vscsi");
1888 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");