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_TARGET_FAILURE:
 337                 host_status = XEN_VSCSIIF_RSLT_HOST_TARGET_FAILURE;
 338                 break;
 339         case DID_NEXUS_FAILURE:
 340                 host_status = XEN_VSCSIIF_RSLT_HOST_NEXUS_FAILURE;
 341                 break;
 342         case DID_ALLOC_FAILURE:
 343                 host_status = XEN_VSCSIIF_RSLT_HOST_ALLOC_FAILURE;
 344                 break;
 345         case DID_MEDIUM_ERROR:
 346                 host_status = XEN_VSCSIIF_RSLT_HOST_MEDIUM_ERROR;
 347                 break;
 348         case DID_TRANSPORT_MARGINAL:
 349                 host_status = XEN_VSCSIIF_RSLT_HOST_TRANSPORT_MARGINAL;
 350                 break;
 351         default:
 352                 host_status = XEN_VSCSIIF_RSLT_HOST_ERROR;
 353                 break;
 354         }
 355
 356         return (host_status << 16) | (result & 0x00ffff);
 357 }
 358
 359 static void scsiback_send_response(struct vscsibk_info *info,
 360                         char *sense_buffer, int32_t result, uint32_t resid,
 361                         uint16_t rqid)
 362 {
 363         struct vscsiif_response *ring_res;
 364         int notify;
 365         struct scsi_sense_hdr sshdr;
 366         unsigned long flags;
 367         unsigned len;
 368
 369         spin_lock_irqsave(&info->ring_lock, flags);
 370
 371         ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
 372         info->ring.rsp_prod_pvt++;
 373
 374         ring_res->rslt   = scsiback_result(result);
 375         ring_res->rqid   = rqid;
 376
 377         if (sense_buffer != NULL &&
 378             scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
 379                                  &sshdr)) {
 380                 len = min_t(unsigned, 8 + sense_buffer[7],
 381                             VSCSIIF_SENSE_BUFFERSIZE);
 382                 memcpy(ring_res->sense_buffer, sense_buffer, len);
 383                 ring_res->sense_len = len;
 384         } else {
 385                 ring_res->sense_len = 0;
 386         }
 387
 388         ring_res->residual_len = resid;
 389
 390         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
 391         spin_unlock_irqrestore(&info->ring_lock, flags);
 392
 393         if (notify)
 394                 notify_remote_via_irq(info->irq);
 395 }
 396
 397 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
 398                         uint32_t resid, struct vscsibk_pend *pending_req)
 399 {
 400         scsiback_send_response(pending_req->info, sense_buffer, result,
 401                                resid, pending_req->rqid);
 402
 403         if (pending_req->v2p)
 404                 kref_put(&pending_req->v2p->kref,
 405                          scsiback_free_translation_entry);
 406 }
 407
 408 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
 409 {
 410         struct vscsibk_info *info = pending_req->info;
 411         unsigned char *sense_buffer;
 412         unsigned int resid;
 413         int errors;
 414
 415         sense_buffer = pending_req->sense_buffer;
 416         resid        = pending_req->se_cmd.residual_count;
 417         errors       = pending_req->result;
 418
 419         if (errors && log_print_stat)
 420                 scsiback_print_status(sense_buffer, errors, pending_req);
 421
 422         scsiback_fast_flush_area(pending_req);
 423         scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
 424         scsiback_put(info);
 425         /*
 426          * Drop the extra KREF_ACK reference taken by target_submit_cmd_map_sgls()
 427          * ahead of scsiback_check_stop_free() ->  transport_generic_free_cmd()
 428          * final se_cmd->cmd_kref put.
 429          */
 430         target_put_sess_cmd(&pending_req->se_cmd);
 431 }
 432
 433 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
 434 {
 435         struct se_cmd *se_cmd = &pending_req->se_cmd;
 436         struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
 437
 438         scsiback_get(pending_req->info);
 439         se_cmd->tag = pending_req->rqid;
 440         target_init_cmd(se_cmd, sess, pending_req->sense_buffer,
 441                         pending_req->v2p->lun, pending_req->data_len, 0,
 442                         pending_req->sc_data_direction, TARGET_SCF_ACK_KREF);
 443
 444         if (target_submit_prep(se_cmd, pending_req->cmnd, pending_req->sgl,
 445                                pending_req->n_sg, NULL, 0, NULL, 0, GFP_KERNEL))
 446                 return;
 447
 448         target_submit(se_cmd);
 449 }
 450
 451 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 452         struct page **pg, grant_handle_t *grant, int cnt)
 453 {
 454         int err, i;
 455
 456         if (!cnt)
 457                 return 0;
 458
 459         err = gnttab_map_refs(map, NULL, pg, cnt);
 460         for (i = 0; i < cnt; i++) {
 461                 if (unlikely(map[i].status != GNTST_okay)) {
 462                         pr_err("invalid buffer -- could not remap it\n");
 463                         map[i].handle = SCSIBACK_INVALID_HANDLE;
 464                         if (!err)
 465                                 err = -ENOMEM;
 466                 } else {
 467                         get_page(pg[i]);
 468                 }
 469                 grant[i] = map[i].handle;
 470         }
 471         return err;
 472 }
 473
 474 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
 475                         struct scsiif_request_segment *seg, struct page **pg,
 476                         grant_handle_t *grant, int cnt, u32 flags)
 477 {
 478         int mapcount = 0, i, err = 0;
 479         struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
 480         struct vscsibk_info *info = pending_req->info;
 481
 482         for (i = 0; i < cnt; i++) {
 483                 if (gnttab_page_cache_get(&info->free_pages, pg + mapcount)) {
 484                         gnttab_page_cache_put(&info->free_pages, pg, mapcount);
 485                         pr_err("no grant page\n");
 486                         return -ENOMEM;
 487                 }
 488                 gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
 489                                   flags, seg[i].gref, info->domid);
 490                 mapcount++;
 491                 if (mapcount < VSCSI_GRANT_BATCH)
 492                         continue;
 493                 err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 494                 pg += mapcount;
 495                 grant += mapcount;
 496                 pending_req->n_grants += mapcount;
 497                 if (err)
 498                         return err;
 499                 mapcount = 0;
 500         }
 501         err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 502         pending_req->n_grants += mapcount;
 503         return err;
 504 }
 505
 506 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 507                                         struct vscsibk_pend *pending_req)
 508 {
 509         u32 flags;
 510         int i, err, n_segs, i_seg = 0;
 511         struct page **pg;
 512         struct scsiif_request_segment *seg;
 513         unsigned long end_seg = 0;
 514         unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
 515         unsigned int nr_sgl = 0;
 516         struct scatterlist *sg;
 517         grant_handle_t *grant;
 518
 519         pending_req->n_sg = 0;
 520         pending_req->n_grants = 0;
 521         pending_req->data_len = 0;
 522
 523         nr_segments &= ~VSCSIIF_SG_GRANT;
 524         if (!nr_segments)
 525                 return 0;
 526
 527         if (nr_segments > VSCSIIF_SG_TABLESIZE) {
 528                 pr_debug("invalid parameter nr_seg = %d\n",
 529                         ring_req->nr_segments);
 530                 return -EINVAL;
 531         }
 532
 533         if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
 534                 err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
 535                         pending_req->pages, pending_req->grant_handles,
 536                         nr_segments, GNTMAP_host_map | GNTMAP_readonly);
 537                 if (err)
 538                         return err;
 539                 nr_sgl = nr_segments;
 540                 nr_segments = 0;
 541                 for (i = 0; i < nr_sgl; i++) {
 542                         n_segs = ring_req->seg[i].length /
 543                                  sizeof(struct scsiif_request_segment);
 544                         if ((unsigned)ring_req->seg[i].offset +
 545                             (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
 546                             n_segs * sizeof(struct scsiif_request_segment) !=
 547                             ring_req->seg[i].length)
 548                                 return -EINVAL;
 549                         nr_segments += n_segs;
 550                 }
 551                 if (nr_segments > SG_ALL) {
 552                         pr_debug("invalid nr_seg = %d\n", nr_segments);
 553                         return -EINVAL;
 554                 }
 555         }
 556
 557         /* free of (sgl) in fast_flush_area() */
 558         pending_req->sgl = kmalloc_array(nr_segments,
 559                                         sizeof(struct scatterlist), GFP_KERNEL);
 560         if (!pending_req->sgl)
 561                 return -ENOMEM;
 562
 563         sg_init_table(pending_req->sgl, nr_segments);
 564         pending_req->n_sg = nr_segments;
 565
 566         flags = GNTMAP_host_map;
 567         if (pending_req->sc_data_direction == DMA_TO_DEVICE)
 568                 flags |= GNTMAP_readonly;
 569
 570         pg = pending_req->pages + nr_sgl;
 571         grant = pending_req->grant_handles + nr_sgl;
 572         if (!nr_sgl) {
 573                 seg = ring_req->seg;
 574                 err = scsiback_gnttab_data_map_list(pending_req, seg,
 575                         pg, grant, nr_segments, flags);
 576                 if (err)
 577                         return err;
 578         } else {
 579                 for (i = 0; i < nr_sgl; i++) {
 580                         seg = (struct scsiif_request_segment *)(
 581                               vaddr(pending_req, i) + ring_req->seg[i].offset);
 582                         n_segs = ring_req->seg[i].length /
 583                                  sizeof(struct scsiif_request_segment);
 584                         err = scsiback_gnttab_data_map_list(pending_req, seg,
 585                                 pg, grant, n_segs, flags);
 586                         if (err)
 587                                 return err;
 588                         pg += n_segs;
 589                         grant += n_segs;
 590                 }
 591                 end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
 592                 seg = (struct scsiif_request_segment *)end_seg;
 593                 end_seg += ring_req->seg[0].length;
 594                 pg = pending_req->pages + nr_sgl;
 595         }
 596
 597         for_each_sg(pending_req->sgl, sg, nr_segments, i) {
 598                 sg_set_page(sg, pg[i], seg->length, seg->offset);
 599                 pending_req->data_len += seg->length;
 600                 seg++;
 601                 if (nr_sgl && (unsigned long)seg >= end_seg) {
 602                         i_seg++;
 603                         end_seg = vaddr(pending_req, i_seg) +
 604                                   ring_req->seg[i_seg].offset;
 605                         seg = (struct scsiif_request_segment *)end_seg;
 606                         end_seg += ring_req->seg[i_seg].length;
 607                 }
 608                 if (sg->offset >= PAGE_SIZE ||
 609                     sg->length > PAGE_SIZE ||
 610                     sg->offset + sg->length > PAGE_SIZE)
 611                         return -EINVAL;
 612         }
 613
 614         return 0;
 615 }
 616
 617 static void scsiback_disconnect(struct vscsibk_info *info)
 618 {
 619         wait_event(info->waiting_to_free,
 620                 atomic_read(&info->nr_unreplied_reqs) == 0);
 621
 622         unbind_from_irqhandler(info->irq, info);
 623         info->irq = 0;
 624         xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
 625 }
 626
 627 static void scsiback_device_action(struct vscsibk_pend *pending_req,
 628         enum tcm_tmreq_table act, int tag)
 629 {
 630         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 631         struct scsiback_nexus *nexus = tpg->tpg_nexus;
 632         struct se_cmd *se_cmd = &pending_req->se_cmd;
 633         u64 unpacked_lun = pending_req->v2p->lun;
 634         int rc, err = XEN_VSCSIIF_RSLT_RESET_FAILED;
 635
 636         init_completion(&pending_req->tmr_done);
 637
 638         rc = target_submit_tmr(&pending_req->se_cmd, nexus->tvn_se_sess,
 639                                &pending_req->sense_buffer[0],
 640                                unpacked_lun, NULL, act, GFP_KERNEL,
 641                                tag, TARGET_SCF_ACK_KREF);
 642         if (rc)
 643                 goto err;
 644
 645         wait_for_completion(&pending_req->tmr_done);
 646
 647         err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
 648                 XEN_VSCSIIF_RSLT_RESET_SUCCESS : XEN_VSCSIIF_RSLT_RESET_FAILED;
 649
 650         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 651         transport_generic_free_cmd(&pending_req->se_cmd, 0);
 652         return;
 653
 654 err:
 655         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 656 }
 657
 658 /*
 659   Perform virtual to physical translation
 660 */
 661 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
 662                         struct ids_tuple *v)
 663 {
 664         struct v2p_entry *entry;
 665         struct list_head *head = &(info->v2p_entry_lists);
 666         unsigned long flags;
 667
 668         spin_lock_irqsave(&info->v2p_lock, flags);
 669         list_for_each_entry(entry, head, l) {
 670                 if ((entry->v.chn == v->chn) &&
 671                     (entry->v.tgt == v->tgt) &&
 672                     (entry->v.lun == v->lun)) {
 673                         kref_get(&entry->kref);
 674                         goto out;
 675                 }
 676         }
 677         entry = NULL;
 678
 679 out:
 680         spin_unlock_irqrestore(&info->v2p_lock, flags);
 681         return entry;
 682 }
 683
 684 static struct vscsibk_pend *scsiback_get_pend_req(struct vscsiif_back_ring *ring,
 685                                 struct v2p_entry *v2p)
 686 {
 687         struct scsiback_tpg *tpg = v2p->tpg;
 688         struct scsiback_nexus *nexus = tpg->tpg_nexus;
 689         struct se_session *se_sess = nexus->tvn_se_sess;
 690         struct vscsibk_pend *req;
 691         int tag, cpu, i;
 692
 693         tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
 694         if (tag < 0) {
 695                 pr_err("Unable to obtain tag for vscsiif_request\n");
 696                 return ERR_PTR(-ENOMEM);
 697         }
 698
 699         req = &((struct vscsibk_pend *)se_sess->sess_cmd_map)[tag];
 700         memset(req, 0, sizeof(*req));
 701         req->se_cmd.map_tag = tag;
 702         req->se_cmd.map_cpu = cpu;
 703
 704         for (i = 0; i < VSCSI_MAX_GRANTS; i++)
 705                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 706
 707         return req;
 708 }
 709
 710 static struct vscsibk_pend *prepare_pending_reqs(struct vscsibk_info *info,
 711                                 struct vscsiif_back_ring *ring,
 712                                 struct vscsiif_request *ring_req)
 713 {
 714         struct vscsibk_pend *pending_req;
 715         struct v2p_entry *v2p;
 716         struct ids_tuple vir;
 717
 718         /* request range check from frontend */
 719         if ((ring_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
 720                 (ring_req->sc_data_direction != DMA_TO_DEVICE) &&
 721                 (ring_req->sc_data_direction != DMA_FROM_DEVICE) &&
 722                 (ring_req->sc_data_direction != DMA_NONE)) {
 723                 pr_debug("invalid parameter data_dir = %d\n",
 724                         ring_req->sc_data_direction);
 725                 return ERR_PTR(-EINVAL);
 726         }
 727         if (ring_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
 728                 pr_debug("invalid parameter cmd_len = %d\n",
 729                         ring_req->cmd_len);
 730                 return ERR_PTR(-EINVAL);
 731         }
 732
 733         vir.chn = ring_req->channel;
 734         vir.tgt = ring_req->id;
 735         vir.lun = ring_req->lun;
 736
 737         v2p = scsiback_do_translation(info, &vir);
 738         if (!v2p) {
 739                 pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
 740                          vir.chn, vir.tgt, vir.lun);
 741                 return ERR_PTR(-ENODEV);
 742         }
 743
 744         pending_req = scsiback_get_pend_req(ring, v2p);
 745         if (IS_ERR(pending_req)) {
 746                 kref_put(&v2p->kref, scsiback_free_translation_entry);
 747                 return ERR_PTR(-ENOMEM);
 748         }
 749         pending_req->rqid = ring_req->rqid;
 750         pending_req->info = info;
 751         pending_req->v2p = v2p;
 752         pending_req->sc_data_direction = ring_req->sc_data_direction;
 753         pending_req->cmd_len = ring_req->cmd_len;
 754         memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
 755
 756         return pending_req;
 757 }
 758
 759 static int scsiback_do_cmd_fn(struct vscsibk_info *info,
 760                               unsigned int *eoi_flags)
 761 {
 762         struct vscsiif_back_ring *ring = &info->ring;
 763         struct vscsiif_request ring_req;
 764         struct vscsibk_pend *pending_req;
 765         RING_IDX rc, rp;
 766         int more_to_do;
 767         uint32_t result;
 768
 769         rc = ring->req_cons;
 770         rp = ring->sring->req_prod;
 771         rmb();  /* guest system is accessing ring, too */
 772
 773         if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
 774                 rc = ring->rsp_prod_pvt;
 775                 pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 776                            info->domid, rp, rc, rp - rc);
 777                 return -EINVAL;
 778         }
 779
 780         while ((rc != rp)) {
 781                 *eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS;
 782
 783                 if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
 784                         break;
 785
 786                 RING_COPY_REQUEST(ring, rc, &ring_req);
 787                 ring->req_cons = ++rc;
 788
 789                 pending_req = prepare_pending_reqs(info, ring, &ring_req);
 790                 if (IS_ERR(pending_req)) {
 791                         switch (PTR_ERR(pending_req)) {
 792                         case -ENODEV:
 793                                 result = DID_NO_CONNECT;
 794                                 break;
 795                         default:
 796                                 result = DID_ERROR;
 797                                 break;
 798                         }
 799                         scsiback_send_response(info, NULL, result << 16, 0,
 800                                                ring_req.rqid);
 801                         return 1;
 802                 }
 803
 804                 switch (ring_req.act) {
 805                 case VSCSIIF_ACT_SCSI_CDB:
 806                         if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
 807                                 scsiback_fast_flush_area(pending_req);
 808                                 scsiback_do_resp_with_sense(NULL,
 809                                                 DID_ERROR << 16, 0, pending_req);
 810                                 transport_generic_free_cmd(&pending_req->se_cmd, 0);
 811                         } else {
 812                                 scsiback_cmd_exec(pending_req);
 813                         }
 814                         break;
 815                 case VSCSIIF_ACT_SCSI_ABORT:
 816                         scsiback_device_action(pending_req, TMR_ABORT_TASK,
 817                                 ring_req.ref_rqid);
 818                         break;
 819                 case VSCSIIF_ACT_SCSI_RESET:
 820                         scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
 821                         break;
 822                 default:
 823                         pr_err_ratelimited("invalid request\n");
 824                         scsiback_do_resp_with_sense(NULL, DID_ERROR << 16, 0,
 825                                                     pending_req);
 826                         transport_generic_free_cmd(&pending_req->se_cmd, 0);
 827                         break;
 828                 }
 829
 830                 /* Yield point for this unbounded loop. */
 831                 cond_resched();
 832         }
 833
 834         gnttab_page_cache_shrink(&info->free_pages, scsiback_max_buffer_pages);
 835
 836         RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
 837         return more_to_do;
 838 }
 839
 840 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
 841 {
 842         struct vscsibk_info *info = dev_id;
 843         int rc;
 844         unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
 845
 846         while ((rc = scsiback_do_cmd_fn(info, &eoi_flags)) > 0)
 847                 cond_resched();
 848
 849         /* In case of a ring error we keep the event channel masked. */
 850         if (!rc)
 851                 xen_irq_lateeoi(irq, eoi_flags);
 852
 853         return IRQ_HANDLED;
 854 }
 855
 856 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 857                         evtchn_port_t evtchn)
 858 {
 859         void *area;
 860         struct vscsiif_sring *sring;
 861         int err;
 862
 863         if (info->irq)
 864                 return -1;
 865
 866         err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 867         if (err)
 868                 return err;
 869
 870         sring = (struct vscsiif_sring *)area;
 871         BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 872
 873         err = bind_interdomain_evtchn_to_irq_lateeoi(info->dev, evtchn);
 874         if (err < 0)
 875                 goto unmap_page;
 876
 877         info->irq = err;
 878
 879         err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
 880                                    IRQF_ONESHOT, "vscsiif-backend", info);
 881         if (err)
 882                 goto free_irq;
 883
 884         return 0;
 885
 886 free_irq:
 887         unbind_from_irqhandler(info->irq, info);
 888         info->irq = 0;
 889 unmap_page:
 890         xenbus_unmap_ring_vfree(info->dev, area);
 891
 892         return err;
 893 }
 894
 895 static int scsiback_map(struct vscsibk_info *info)
 896 {
 897         struct xenbus_device *dev = info->dev;
 898         unsigned int ring_ref;
 899         evtchn_port_t evtchn;
 900         int err;
 901
 902         err = xenbus_gather(XBT_NIL, dev->otherend,
 903                         "ring-ref", "%u", &ring_ref,
 904                         "event-channel", "%u", &evtchn, NULL);
 905         if (err) {
 906                 xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
 907                 return err;
 908         }
 909
 910         return scsiback_init_sring(info, ring_ref, evtchn);
 911 }
 912
 913 /*
 914   Check for a translation entry being present
 915 */
 916 static struct v2p_entry *scsiback_chk_translation_entry(
 917         struct vscsibk_info *info, struct ids_tuple *v)
 918 {
 919         struct list_head *head = &(info->v2p_entry_lists);
 920         struct v2p_entry *entry;
 921
 922         list_for_each_entry(entry, head, l)
 923                 if ((entry->v.chn == v->chn) &&
 924                     (entry->v.tgt == v->tgt) &&
 925                     (entry->v.lun == v->lun))
 926                         return entry;
 927
 928         return NULL;
 929 }
 930
 931 /*
 932   Add a new translation entry
 933 */
 934 static int scsiback_add_translation_entry(struct vscsibk_info *info,
 935                                           char *phy, struct ids_tuple *v)
 936 {
 937         int err = 0;
 938         struct v2p_entry *new;
 939         unsigned long flags;
 940         char *lunp;
 941         unsigned long long unpacked_lun;
 942         struct se_lun *se_lun;
 943         struct scsiback_tpg *tpg_entry, *tpg = NULL;
 944         char *error = "doesn't exist";
 945
 946         lunp = strrchr(phy, ':');
 947         if (!lunp) {
 948                 pr_err("illegal format of physical device %s\n", phy);
 949                 return -EINVAL;
 950         }
 951         *lunp = 0;
 952         lunp++;
 953         err = kstrtoull(lunp, 10, &unpacked_lun);
 954         if (err < 0) {
 955                 pr_err("lun number not valid: %s\n", lunp);
 956                 return err;
 957         }
 958
 959         mutex_lock(&scsiback_mutex);
 960         list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
 961                 if (!strcmp(phy, tpg_entry->tport->tport_name) ||
 962                     !strcmp(phy, tpg_entry->param_alias)) {
 963                         mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
 964                         hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
 965                                 if (se_lun->unpacked_lun == unpacked_lun) {
 966                                         if (!tpg_entry->tpg_nexus)
 967                                                 error = "nexus undefined";
 968                                         else
 969                                                 tpg = tpg_entry;
 970                                         break;
 971                                 }
 972                         }
 973                         mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
 974                         break;
 975                 }
 976         }
 977         if (tpg) {
 978                 mutex_lock(&tpg->tv_tpg_mutex);
 979                 tpg->tv_tpg_fe_count++;
 980                 mutex_unlock(&tpg->tv_tpg_mutex);
 981         }
 982         mutex_unlock(&scsiback_mutex);
 983
 984         if (!tpg) {
 985                 pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
 986                 return -ENODEV;
 987         }
 988
 989         new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
 990         if (new == NULL) {
 991                 err = -ENOMEM;
 992                 goto out_free;
 993         }
 994
 995         spin_lock_irqsave(&info->v2p_lock, flags);
 996
 997         /* Check double assignment to identical virtual ID */
 998         if (scsiback_chk_translation_entry(info, v)) {
 999                 pr_warn("Virtual ID is already used. Assignment was not performed.\n");
1000                 err = -EEXIST;
1001                 goto out;
1002         }
1003
1004         /* Create a new translation entry and add to the list */
1005         kref_init(&new->kref);
1006         new->v = *v;
1007         new->tpg = tpg;
1008         new->lun = unpacked_lun;
1009         list_add_tail(&new->l, &info->v2p_entry_lists);
1010
1011 out:
1012         spin_unlock_irqrestore(&info->v2p_lock, flags);
1013
1014 out_free:
1015         if (err) {
1016                 mutex_lock(&tpg->tv_tpg_mutex);
1017                 tpg->tv_tpg_fe_count--;
1018                 mutex_unlock(&tpg->tv_tpg_mutex);
1019                 kfree(new);
1020         }
1021
1022         return err;
1023 }
1024
1025 static void __scsiback_del_translation_entry(struct v2p_entry *entry)
1026 {
1027         list_del(&entry->l);
1028         kref_put(&entry->kref, scsiback_free_translation_entry);
1029 }
1030
1031 /*
1032   Delete the translation entry specified
1033 */
1034 static int scsiback_del_translation_entry(struct vscsibk_info *info,
1035                                           struct ids_tuple *v)
1036 {
1037         struct v2p_entry *entry;
1038         unsigned long flags;
1039         int ret = 0;
1040
1041         spin_lock_irqsave(&info->v2p_lock, flags);
1042         /* Find out the translation entry specified */
1043         entry = scsiback_chk_translation_entry(info, v);
1044         if (entry)
1045                 __scsiback_del_translation_entry(entry);
1046         else
1047                 ret = -ENOENT;
1048
1049         spin_unlock_irqrestore(&info->v2p_lock, flags);
1050         return ret;
1051 }
1052
1053 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
1054                                 char *phy, struct ids_tuple *vir, int try)
1055 {
1056         struct v2p_entry *entry;
1057         unsigned long flags;
1058         int err;
1059
1060         if (try) {
1061                 spin_lock_irqsave(&info->v2p_lock, flags);
1062                 entry = scsiback_chk_translation_entry(info, vir);
1063                 spin_unlock_irqrestore(&info->v2p_lock, flags);
1064                 if (entry)
1065                         return;
1066         }
1067         if (!scsiback_add_translation_entry(info, phy, vir)) {
1068                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1069                                   "%d", XenbusStateInitialised)) {
1070                         pr_err("xenbus_printf error %s\n", state);
1071                         scsiback_del_translation_entry(info, vir);
1072                 }
1073         } else if (!try) {
1074                 err = xenbus_printf(XBT_NIL, info->dev->nodename, state,
1075                               "%d", XenbusStateClosed);
1076                 if (err)
1077                         xenbus_dev_error(info->dev, err,
1078                                 "%s: writing %s", __func__, state);
1079         }
1080 }
1081
1082 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1083                                 struct ids_tuple *vir)
1084 {
1085         if (!scsiback_del_translation_entry(info, vir)) {
1086                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1087                                   "%d", XenbusStateClosed))
1088                         pr_err("xenbus_printf error %s\n", state);
1089         }
1090 }
1091
1092 #define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1093 #define VSCSIBACK_OP_UPDATEDEV_STATE    2
1094
1095 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1096                                      char *ent)
1097 {
1098         int err;
1099         struct ids_tuple vir;
1100         char *val;
1101         int device_state;
1102         char phy[VSCSI_NAMELEN];
1103         char str[64];
1104         char state[64];
1105         struct xenbus_device *dev = info->dev;
1106
1107         /* read status */
1108         snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1109         err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1110         if (XENBUS_EXIST_ERR(err))
1111                 return;
1112
1113         /* physical SCSI device */
1114         snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1115         val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1116         if (IS_ERR(val)) {
1117                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1118                               "%d", XenbusStateClosed);
1119                 if (err)
1120                         xenbus_dev_error(info->dev, err,
1121                                 "%s: writing %s", __func__, state);
1122                 return;
1123         }
1124         strlcpy(phy, val, VSCSI_NAMELEN);
1125         kfree(val);
1126
1127         /* virtual SCSI device */
1128         snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1129         err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1130                            &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1131         if (XENBUS_EXIST_ERR(err)) {
1132                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1133                               "%d", XenbusStateClosed);
1134                 if (err)
1135                         xenbus_dev_error(info->dev, err,
1136                                 "%s: writing %s", __func__, state);
1137                 return;
1138         }
1139
1140         switch (op) {
1141         case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1142                 switch (device_state) {
1143                 case XenbusStateInitialising:
1144                         scsiback_do_add_lun(info, state, phy, &vir, 0);
1145                         break;
1146                 case XenbusStateConnected:
1147                         scsiback_do_add_lun(info, state, phy, &vir, 1);
1148                         break;
1149                 case XenbusStateClosing:
1150                         scsiback_do_del_lun(info, state, &vir);
1151                         break;
1152                 default:
1153                         break;
1154                 }
1155                 break;
1156
1157         case VSCSIBACK_OP_UPDATEDEV_STATE:
1158                 if (device_state == XenbusStateInitialised) {
1159                         /* modify vscsi-devs/dev-x/state */
1160                         if (xenbus_printf(XBT_NIL, dev->nodename, state,
1161                                           "%d", XenbusStateConnected)) {
1162                                 pr_err("xenbus_printf error %s\n", str);
1163                                 scsiback_del_translation_entry(info, &vir);
1164                                 xenbus_printf(XBT_NIL, dev->nodename, state,
1165                                               "%d", XenbusStateClosed);
1166                         }
1167                 }
1168                 break;
1169         /* When it is necessary, processing is added here. */
1170         default:
1171                 break;
1172         }
1173 }
1174
1175 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1176 {
1177         int i;
1178         char **dir;
1179         unsigned int ndir = 0;
1180
1181         dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1182                                &ndir);
1183         if (IS_ERR(dir))
1184                 return;
1185
1186         for (i = 0; i < ndir; i++)
1187                 scsiback_do_1lun_hotplug(info, op, dir[i]);
1188
1189         kfree(dir);
1190 }
1191
1192 static void scsiback_frontend_changed(struct xenbus_device *dev,
1193                                         enum xenbus_state frontend_state)
1194 {
1195         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1196
1197         switch (frontend_state) {
1198         case XenbusStateInitialising:
1199                 break;
1200
1201         case XenbusStateInitialised:
1202                 if (scsiback_map(info))
1203                         break;
1204
1205                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1206                 xenbus_switch_state(dev, XenbusStateConnected);
1207                 break;
1208
1209         case XenbusStateConnected:
1210                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1211
1212                 if (dev->state == XenbusStateConnected)
1213                         break;
1214
1215                 xenbus_switch_state(dev, XenbusStateConnected);
1216                 break;
1217
1218         case XenbusStateClosing:
1219                 if (info->irq)
1220                         scsiback_disconnect(info);
1221
1222                 xenbus_switch_state(dev, XenbusStateClosing);
1223                 break;
1224
1225         case XenbusStateClosed:
1226                 xenbus_switch_state(dev, XenbusStateClosed);
1227                 if (xenbus_dev_is_online(dev))
1228                         break;
1229                 fallthrough;    /* if not online */
1230         case XenbusStateUnknown:
1231                 device_unregister(&dev->dev);
1232                 break;
1233
1234         case XenbusStateReconfiguring:
1235                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1236                 xenbus_switch_state(dev, XenbusStateReconfigured);
1237
1238                 break;
1239
1240         default:
1241                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1242                                         frontend_state);
1243                 break;
1244         }
1245 }
1246
1247 /*
1248   Release the translation entry specfied
1249 */
1250 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1251 {
1252         struct v2p_entry *entry, *tmp;
1253         struct list_head *head = &(info->v2p_entry_lists);
1254         unsigned long flags;
1255
1256         spin_lock_irqsave(&info->v2p_lock, flags);
1257
1258         list_for_each_entry_safe(entry, tmp, head, l)
1259                 __scsiback_del_translation_entry(entry);
1260
1261         spin_unlock_irqrestore(&info->v2p_lock, flags);
1262 }
1263
1264 static int scsiback_remove(struct xenbus_device *dev)
1265 {
1266         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1267
1268         if (info->irq)
1269                 scsiback_disconnect(info);
1270
1271         scsiback_release_translation_entry(info);
1272
1273         gnttab_page_cache_shrink(&info->free_pages, 0);
1274
1275         dev_set_drvdata(&dev->dev, NULL);
1276
1277         return 0;
1278 }
1279
1280 static int scsiback_probe(struct xenbus_device *dev,
1281                            const struct xenbus_device_id *id)
1282 {
1283         int err;
1284
1285         struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1286                                             GFP_KERNEL);
1287
1288         pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1289
1290         if (!info) {
1291                 xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1292                 return -ENOMEM;
1293         }
1294         info->dev = dev;
1295         dev_set_drvdata(&dev->dev, info);
1296
1297         info->domid = dev->otherend_id;
1298         spin_lock_init(&info->ring_lock);
1299         atomic_set(&info->nr_unreplied_reqs, 0);
1300         init_waitqueue_head(&info->waiting_to_free);
1301         info->dev = dev;
1302         info->irq = 0;
1303         INIT_LIST_HEAD(&info->v2p_entry_lists);
1304         spin_lock_init(&info->v2p_lock);
1305         gnttab_page_cache_init(&info->free_pages);
1306
1307         err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1308                             SG_ALL);
1309         if (err)
1310                 xenbus_dev_error(dev, err, "writing feature-sg-grant");
1311
1312         err = xenbus_switch_state(dev, XenbusStateInitWait);
1313         if (err)
1314                 goto fail;
1315
1316         return 0;
1317
1318 fail:
1319         pr_warn("%s failed\n", __func__);
1320         scsiback_remove(dev);
1321
1322         return err;
1323 }
1324
1325 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1326 {
1327         switch (tport->tport_proto_id) {
1328         case SCSI_PROTOCOL_SAS:
1329                 return "SAS";
1330         case SCSI_PROTOCOL_FCP:
1331                 return "FCP";
1332         case SCSI_PROTOCOL_ISCSI:
1333                 return "iSCSI";
1334         default:
1335                 break;
1336         }
1337
1338         return "Unknown";
1339 }
1340
1341 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1342 {
1343         struct scsiback_tpg *tpg = container_of(se_tpg,
1344                                 struct scsiback_tpg, se_tpg);
1345         struct scsiback_tport *tport = tpg->tport;
1346
1347         return &tport->tport_name[0];
1348 }
1349
1350 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1351 {
1352         struct scsiback_tpg *tpg = container_of(se_tpg,
1353                                 struct scsiback_tpg, se_tpg);
1354         return tpg->tport_tpgt;
1355 }
1356
1357 static struct se_wwn *
1358 scsiback_make_tport(struct target_fabric_configfs *tf,
1359                      struct config_group *group,
1360                      const char *name)
1361 {
1362         struct scsiback_tport *tport;
1363         char *ptr;
1364         u64 wwpn = 0;
1365         int off = 0;
1366
1367         tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1368         if (!tport)
1369                 return ERR_PTR(-ENOMEM);
1370
1371         tport->tport_wwpn = wwpn;
1372         /*
1373          * Determine the emulated Protocol Identifier and Target Port Name
1374          * based on the incoming configfs directory name.
1375          */
1376         ptr = strstr(name, "naa.");
1377         if (ptr) {
1378                 tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1379                 goto check_len;
1380         }
1381         ptr = strstr(name, "fc.");
1382         if (ptr) {
1383                 tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1384                 off = 3; /* Skip over "fc." */
1385                 goto check_len;
1386         }
1387         ptr = strstr(name, "iqn.");
1388         if (ptr) {
1389                 tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1390                 goto check_len;
1391         }
1392
1393         pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1394         kfree(tport);
1395         return ERR_PTR(-EINVAL);
1396
1397 check_len:
1398         if (strlen(name) >= VSCSI_NAMELEN) {
1399                 pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1400                         scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1401                 kfree(tport);
1402                 return ERR_PTR(-EINVAL);
1403         }
1404         snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1405
1406         pr_debug("Allocated emulated Target %s Address: %s\n",
1407                  scsiback_dump_proto_id(tport), name);
1408
1409         return &tport->tport_wwn;
1410 }
1411
1412 static void scsiback_drop_tport(struct se_wwn *wwn)
1413 {
1414         struct scsiback_tport *tport = container_of(wwn,
1415                                 struct scsiback_tport, tport_wwn);
1416
1417         pr_debug("Deallocating emulated Target %s Address: %s\n",
1418                  scsiback_dump_proto_id(tport), tport->tport_name);
1419
1420         kfree(tport);
1421 }
1422
1423 static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1424 {
1425         return 1;
1426 }
1427
1428 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1429 {
1430         return transport_generic_free_cmd(se_cmd, 0);
1431 }
1432
1433 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1434 {
1435         target_free_tag(se_cmd->se_sess, se_cmd);
1436 }
1437
1438 static u32 scsiback_sess_get_index(struct se_session *se_sess)
1439 {
1440         return 0;
1441 }
1442
1443 static int scsiback_write_pending(struct se_cmd *se_cmd)
1444 {
1445         /* Go ahead and process the write immediately */
1446         target_execute_cmd(se_cmd);
1447
1448         return 0;
1449 }
1450
1451 static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1452 {
1453 }
1454
1455 static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1456 {
1457         return 0;
1458 }
1459
1460 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1461 {
1462         struct vscsibk_pend *pending_req = container_of(se_cmd,
1463                                 struct vscsibk_pend, se_cmd);
1464
1465         pending_req->result = SAM_STAT_GOOD;
1466         scsiback_cmd_done(pending_req);
1467         return 0;
1468 }
1469
1470 static int scsiback_queue_status(struct se_cmd *se_cmd)
1471 {
1472         struct vscsibk_pend *pending_req = container_of(se_cmd,
1473                                 struct vscsibk_pend, se_cmd);
1474
1475         if (se_cmd->sense_buffer &&
1476             ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1477              (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1478                 pending_req->result = SAM_STAT_CHECK_CONDITION;
1479         else
1480                 pending_req->result = se_cmd->scsi_status;
1481
1482         scsiback_cmd_done(pending_req);
1483         return 0;
1484 }
1485
1486 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1487 {
1488         struct vscsibk_pend *pending_req = container_of(se_cmd,
1489                                 struct vscsibk_pend, se_cmd);
1490
1491         complete(&pending_req->tmr_done);
1492 }
1493
1494 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1495 {
1496 }
1497
1498 static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1499                                              char *page)
1500 {
1501         struct se_portal_group *se_tpg = param_to_tpg(item);
1502         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1503                                                 se_tpg);
1504         ssize_t rb;
1505
1506         mutex_lock(&tpg->tv_tpg_mutex);
1507         rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1508         mutex_unlock(&tpg->tv_tpg_mutex);
1509
1510         return rb;
1511 }
1512
1513 static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1514                                               const char *page, size_t count)
1515 {
1516         struct se_portal_group *se_tpg = param_to_tpg(item);
1517         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1518                                                 se_tpg);
1519         int len;
1520
1521         if (strlen(page) >= VSCSI_NAMELEN) {
1522                 pr_err("param alias: %s, exceeds max: %d\n", page,
1523                         VSCSI_NAMELEN);
1524                 return -EINVAL;
1525         }
1526
1527         mutex_lock(&tpg->tv_tpg_mutex);
1528         len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1529         if (tpg->param_alias[len - 1] == '\n')
1530                 tpg->param_alias[len - 1] = '\0';
1531         mutex_unlock(&tpg->tv_tpg_mutex);
1532
1533         return count;
1534 }
1535
1536 CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1537
1538 static struct configfs_attribute *scsiback_param_attrs[] = {
1539         &scsiback_tpg_param_attr_alias,
1540         NULL,
1541 };
1542
1543 static int scsiback_alloc_sess_cb(struct se_portal_group *se_tpg,
1544                                   struct se_session *se_sess, void *p)
1545 {
1546         struct scsiback_tpg *tpg = container_of(se_tpg,
1547                                 struct scsiback_tpg, se_tpg);
1548
1549         tpg->tpg_nexus = p;
1550         return 0;
1551 }
1552
1553 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1554                                 const char *name)
1555 {
1556         struct scsiback_nexus *tv_nexus;
1557         int ret = 0;
1558
1559         mutex_lock(&tpg->tv_tpg_mutex);
1560         if (tpg->tpg_nexus) {
1561                 pr_debug("tpg->tpg_nexus already exists\n");
1562                 ret = -EEXIST;
1563                 goto out_unlock;
1564         }
1565
1566         tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1567         if (!tv_nexus) {
1568                 ret = -ENOMEM;
1569                 goto out_unlock;
1570         }
1571
1572         tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg,
1573                                                      VSCSI_DEFAULT_SESSION_TAGS,
1574                                                      sizeof(struct vscsibk_pend),
1575                                                      TARGET_PROT_NORMAL, name,
1576                                                      tv_nexus, scsiback_alloc_sess_cb);
1577         if (IS_ERR(tv_nexus->tvn_se_sess)) {
1578                 kfree(tv_nexus);
1579                 ret = -ENOMEM;
1580                 goto out_unlock;
1581         }
1582
1583 out_unlock:
1584         mutex_unlock(&tpg->tv_tpg_mutex);
1585         return ret;
1586 }
1587
1588 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1589 {
1590         struct se_session *se_sess;
1591         struct scsiback_nexus *tv_nexus;
1592
1593         mutex_lock(&tpg->tv_tpg_mutex);
1594         tv_nexus = tpg->tpg_nexus;
1595         if (!tv_nexus) {
1596                 mutex_unlock(&tpg->tv_tpg_mutex);
1597                 return -ENODEV;
1598         }
1599
1600         se_sess = tv_nexus->tvn_se_sess;
1601         if (!se_sess) {
1602                 mutex_unlock(&tpg->tv_tpg_mutex);
1603                 return -ENODEV;
1604         }
1605
1606         if (tpg->tv_tpg_port_count != 0) {
1607                 mutex_unlock(&tpg->tv_tpg_mutex);
1608                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1609                         tpg->tv_tpg_port_count);
1610                 return -EBUSY;
1611         }
1612
1613         if (tpg->tv_tpg_fe_count != 0) {
1614                 mutex_unlock(&tpg->tv_tpg_mutex);
1615                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1616                         tpg->tv_tpg_fe_count);
1617                 return -EBUSY;
1618         }
1619
1620         pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1621                 scsiback_dump_proto_id(tpg->tport),
1622                 tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1623
1624         /*
1625          * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1626          */
1627         target_remove_session(se_sess);
1628         tpg->tpg_nexus = NULL;
1629         mutex_unlock(&tpg->tv_tpg_mutex);
1630
1631         kfree(tv_nexus);
1632         return 0;
1633 }
1634
1635 static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1636 {
1637         struct se_portal_group *se_tpg = to_tpg(item);
1638         struct scsiback_tpg *tpg = container_of(se_tpg,
1639                                 struct scsiback_tpg, se_tpg);
1640         struct scsiback_nexus *tv_nexus;
1641         ssize_t ret;
1642
1643         mutex_lock(&tpg->tv_tpg_mutex);
1644         tv_nexus = tpg->tpg_nexus;
1645         if (!tv_nexus) {
1646                 mutex_unlock(&tpg->tv_tpg_mutex);
1647                 return -ENODEV;
1648         }
1649         ret = snprintf(page, PAGE_SIZE, "%s\n",
1650                         tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1651         mutex_unlock(&tpg->tv_tpg_mutex);
1652
1653         return ret;
1654 }
1655
1656 static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
1657                 const char *page, size_t count)
1658 {
1659         struct se_portal_group *se_tpg = to_tpg(item);
1660         struct scsiback_tpg *tpg = container_of(se_tpg,
1661                                 struct scsiback_tpg, se_tpg);
1662         struct scsiback_tport *tport_wwn = tpg->tport;
1663         unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1664         int ret;
1665         /*
1666          * Shutdown the active I_T nexus if 'NULL' is passed.
1667          */
1668         if (!strncmp(page, "NULL", 4)) {
1669                 ret = scsiback_drop_nexus(tpg);
1670                 return (!ret) ? count : ret;
1671         }
1672         /*
1673          * Otherwise make sure the passed virtual Initiator port WWN matches
1674          * the fabric protocol_id set in scsiback_make_tport(), and call
1675          * scsiback_make_nexus().
1676          */
1677         if (strlen(page) >= VSCSI_NAMELEN) {
1678                 pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1679                         page, VSCSI_NAMELEN);
1680                 return -EINVAL;
1681         }
1682         snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1683
1684         ptr = strstr(i_port, "naa.");
1685         if (ptr) {
1686                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1687                         pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1688                                 i_port, scsiback_dump_proto_id(tport_wwn));
1689                         return -EINVAL;
1690                 }
1691                 port_ptr = &i_port[0];
1692                 goto check_newline;
1693         }
1694         ptr = strstr(i_port, "fc.");
1695         if (ptr) {
1696                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1697                         pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1698                                 i_port, scsiback_dump_proto_id(tport_wwn));
1699                         return -EINVAL;
1700                 }
1701                 port_ptr = &i_port[3]; /* Skip over "fc." */
1702                 goto check_newline;
1703         }
1704         ptr = strstr(i_port, "iqn.");
1705         if (ptr) {
1706                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1707                         pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1708                                 i_port, scsiback_dump_proto_id(tport_wwn));
1709                         return -EINVAL;
1710                 }
1711                 port_ptr = &i_port[0];
1712                 goto check_newline;
1713         }
1714         pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1715                 i_port);
1716         return -EINVAL;
1717         /*
1718          * Clear any trailing newline for the NAA WWN
1719          */
1720 check_newline:
1721         if (i_port[strlen(i_port) - 1] == '\n')
1722                 i_port[strlen(i_port) - 1] = '\0';
1723
1724         ret = scsiback_make_nexus(tpg, port_ptr);
1725         if (ret < 0)
1726                 return ret;
1727
1728         return count;
1729 }
1730
1731 CONFIGFS_ATTR(scsiback_tpg_, nexus);
1732
1733 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1734         &scsiback_tpg_attr_nexus,
1735         NULL,
1736 };
1737
1738 static ssize_t
1739 scsiback_wwn_version_show(struct config_item *item, char *page)
1740 {
1741         return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1742                 UTS_RELEASE"\n",
1743                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1744 }
1745
1746 CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1747
1748 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1749         &scsiback_wwn_attr_version,
1750         NULL,
1751 };
1752
1753 static int scsiback_port_link(struct se_portal_group *se_tpg,
1754                                struct se_lun *lun)
1755 {
1756         struct scsiback_tpg *tpg = container_of(se_tpg,
1757                                 struct scsiback_tpg, se_tpg);
1758
1759         mutex_lock(&tpg->tv_tpg_mutex);
1760         tpg->tv_tpg_port_count++;
1761         mutex_unlock(&tpg->tv_tpg_mutex);
1762
1763         return 0;
1764 }
1765
1766 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1767                                   struct se_lun *lun)
1768 {
1769         struct scsiback_tpg *tpg = container_of(se_tpg,
1770                                 struct scsiback_tpg, se_tpg);
1771
1772         mutex_lock(&tpg->tv_tpg_mutex);
1773         tpg->tv_tpg_port_count--;
1774         mutex_unlock(&tpg->tv_tpg_mutex);
1775 }
1776
1777 static struct se_portal_group *
1778 scsiback_make_tpg(struct se_wwn *wwn, const char *name)
1779 {
1780         struct scsiback_tport *tport = container_of(wwn,
1781                         struct scsiback_tport, tport_wwn);
1782
1783         struct scsiback_tpg *tpg;
1784         u16 tpgt;
1785         int ret;
1786
1787         if (strstr(name, "tpgt_") != name)
1788                 return ERR_PTR(-EINVAL);
1789         ret = kstrtou16(name + 5, 10, &tpgt);
1790         if (ret)
1791                 return ERR_PTR(ret);
1792
1793         tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1794         if (!tpg)
1795                 return ERR_PTR(-ENOMEM);
1796
1797         mutex_init(&tpg->tv_tpg_mutex);
1798         INIT_LIST_HEAD(&tpg->tv_tpg_list);
1799         INIT_LIST_HEAD(&tpg->info_list);
1800         tpg->tport = tport;
1801         tpg->tport_tpgt = tpgt;
1802
1803         ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1804         if (ret < 0) {
1805                 kfree(tpg);
1806                 return NULL;
1807         }
1808         mutex_lock(&scsiback_mutex);
1809         list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1810         mutex_unlock(&scsiback_mutex);
1811
1812         return &tpg->se_tpg;
1813 }
1814
1815 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1816 {
1817         struct scsiback_tpg *tpg = container_of(se_tpg,
1818                                 struct scsiback_tpg, se_tpg);
1819
1820         mutex_lock(&scsiback_mutex);
1821         list_del(&tpg->tv_tpg_list);
1822         mutex_unlock(&scsiback_mutex);
1823         /*
1824          * Release the virtual I_T Nexus for this xen-pvscsi TPG
1825          */
1826         scsiback_drop_nexus(tpg);
1827         /*
1828          * Deregister the se_tpg from TCM.
1829          */
1830         core_tpg_deregister(se_tpg);
1831         kfree(tpg);
1832 }
1833
1834 static int scsiback_check_true(struct se_portal_group *se_tpg)
1835 {
1836         return 1;
1837 }
1838
1839 static int scsiback_check_false(struct se_portal_group *se_tpg)
1840 {
1841         return 0;
1842 }
1843
1844 static const struct target_core_fabric_ops scsiback_ops = {
1845         .module                         = THIS_MODULE,
1846         .fabric_name                    = "xen-pvscsi",
1847         .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1848         .tpg_get_tag                    = scsiback_get_tag,
1849         .tpg_check_demo_mode            = scsiback_check_true,
1850         .tpg_check_demo_mode_cache      = scsiback_check_true,
1851         .tpg_check_demo_mode_write_protect = scsiback_check_false,
1852         .tpg_check_prod_mode_write_protect = scsiback_check_false,
1853         .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1854         .check_stop_free                = scsiback_check_stop_free,
1855         .release_cmd                    = scsiback_release_cmd,
1856         .sess_get_index                 = scsiback_sess_get_index,
1857         .sess_get_initiator_sid         = NULL,
1858         .write_pending                  = scsiback_write_pending,
1859         .set_default_node_attributes    = scsiback_set_default_node_attrs,
1860         .get_cmd_state                  = scsiback_get_cmd_state,
1861         .queue_data_in                  = scsiback_queue_data_in,
1862         .queue_status                   = scsiback_queue_status,
1863         .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1864         .aborted_task                   = scsiback_aborted_task,
1865         /*
1866          * Setup callers for generic logic in target_core_fabric_configfs.c
1867          */
1868         .fabric_make_wwn                = scsiback_make_tport,
1869         .fabric_drop_wwn                = scsiback_drop_tport,
1870         .fabric_make_tpg                = scsiback_make_tpg,
1871         .fabric_drop_tpg                = scsiback_drop_tpg,
1872         .fabric_post_link               = scsiback_port_link,
1873         .fabric_pre_unlink              = scsiback_port_unlink,
1874
1875         .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1876         .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1877         .tfc_tpg_param_attrs            = scsiback_param_attrs,
1878 };
1879
1880 static const struct xenbus_device_id scsiback_ids[] = {
1881         { "vscsi" },
1882         { "" }
1883 };
1884
1885 static struct xenbus_driver scsiback_driver = {
1886         .ids                    = scsiback_ids,
1887         .probe                  = scsiback_probe,
1888         .remove                 = scsiback_remove,
1889         .otherend_changed       = scsiback_frontend_changed
1890 };
1891
1892 static int __init scsiback_init(void)
1893 {
1894         int ret;
1895
1896         if (!xen_domain())
1897                 return -ENODEV;
1898
1899         pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1900                  VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1901
1902         ret = xenbus_register_backend(&scsiback_driver);
1903         if (ret)
1904                 goto out;
1905
1906         ret = target_register_template(&scsiback_ops);
1907         if (ret)
1908                 goto out_unregister_xenbus;
1909
1910         return 0;
1911
1912 out_unregister_xenbus:
1913         xenbus_unregister_driver(&scsiback_driver);
1914 out:
1915         pr_err("%s: error %d\n", __func__, ret);
1916         return ret;
1917 }
1918
1919 static void __exit scsiback_exit(void)
1920 {
1921         target_unregister_template(&scsiback_ops);
1922         xenbus_unregister_driver(&scsiback_driver);
1923 }
1924
1925 module_init(scsiback_init);
1926 module_exit(scsiback_exit);
1927
1928 MODULE_DESCRIPTION("Xen SCSI backend driver");
1929 MODULE_LICENSE("Dual BSD/GPL");
1930 MODULE_ALIAS("xen-backend:vscsi");
1931 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");