drivers/xen/xen-scsiback.c

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