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         struct completion tmr_done;
 139 };
 140
 141 #define VSCSI_DEFAULT_SESSION_TAGS      128
 142
 143 struct scsiback_nexus {
 144         /* Pointer to TCM session for I_T Nexus */
 145         struct se_session *tvn_se_sess;
 146 };
 147
 148 struct scsiback_tport {
 149         /* SCSI protocol the tport is providing */
 150         u8 tport_proto_id;
 151         /* Binary World Wide unique Port Name for pvscsi Target port */
 152         u64 tport_wwpn;
 153         /* ASCII formatted WWPN for pvscsi Target port */
 154         char tport_name[VSCSI_NAMELEN];
 155         /* Returned by scsiback_make_tport() */
 156         struct se_wwn tport_wwn;
 157 };
 158
 159 struct scsiback_tpg {
 160         /* scsiback port target portal group tag for TCM */
 161         u16 tport_tpgt;
 162         /* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
 163         int tv_tpg_port_count;
 164         /* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
 165         int tv_tpg_fe_count;
 166         /* list for scsiback_list */
 167         struct list_head tv_tpg_list;
 168         /* Used to protect access for tpg_nexus */
 169         struct mutex tv_tpg_mutex;
 170         /* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
 171         struct scsiback_nexus *tpg_nexus;
 172         /* Pointer back to scsiback_tport */
 173         struct scsiback_tport *tport;
 174         /* Returned by scsiback_make_tpg() */
 175         struct se_portal_group se_tpg;
 176         /* alias used in xenstore */
 177         char param_alias[VSCSI_NAMELEN];
 178         /* list of info structures related to this target portal group */
 179         struct list_head info_list;
 180 };
 181
 182 #define SCSIBACK_INVALID_HANDLE (~0)
 183
 184 static bool log_print_stat;
 185 module_param(log_print_stat, bool, 0644);
 186
 187 static int scsiback_max_buffer_pages = 1024;
 188 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
 189 MODULE_PARM_DESC(max_buffer_pages,
 190 "Maximum number of free pages to keep in backend buffer");
 191
 192 static DEFINE_SPINLOCK(free_pages_lock);
 193 static int free_pages_num;
 194 static LIST_HEAD(scsiback_free_pages);
 195
 196 /* Global spinlock to protect scsiback TPG list */
 197 static DEFINE_MUTEX(scsiback_mutex);
 198 static LIST_HEAD(scsiback_list);
 199
 200 static void scsiback_get(struct vscsibk_info *info)
 201 {
 202         atomic_inc(&info->nr_unreplied_reqs);
 203 }
 204
 205 static void scsiback_put(struct vscsibk_info *info)
 206 {
 207         if (atomic_dec_and_test(&info->nr_unreplied_reqs))
 208                 wake_up(&info->waiting_to_free);
 209 }
 210
 211 static void put_free_pages(struct page **page, int num)
 212 {
 213         unsigned long flags;
 214         int i = free_pages_num + num, n = num;
 215
 216         if (num == 0)
 217                 return;
 218         if (i > scsiback_max_buffer_pages) {
 219                 n = min(num, i - scsiback_max_buffer_pages);
 220                 gnttab_free_pages(n, page + num - n);
 221                 n = num - n;
 222         }
 223         spin_lock_irqsave(&free_pages_lock, flags);
 224         for (i = 0; i < n; i++)
 225                 list_add(&page[i]->lru, &scsiback_free_pages);
 226         free_pages_num += n;
 227         spin_unlock_irqrestore(&free_pages_lock, flags);
 228 }
 229
 230 static int get_free_page(struct page **page)
 231 {
 232         unsigned long flags;
 233
 234         spin_lock_irqsave(&free_pages_lock, flags);
 235         if (list_empty(&scsiback_free_pages)) {
 236                 spin_unlock_irqrestore(&free_pages_lock, flags);
 237                 return gnttab_alloc_pages(1, page);
 238         }
 239         page[0] = list_first_entry(&scsiback_free_pages, struct page, lru);
 240         list_del(&page[0]->lru);
 241         free_pages_num--;
 242         spin_unlock_irqrestore(&free_pages_lock, flags);
 243         return 0;
 244 }
 245
 246 static unsigned long vaddr_page(struct page *page)
 247 {
 248         unsigned long pfn = page_to_pfn(page);
 249
 250         return (unsigned long)pfn_to_kaddr(pfn);
 251 }
 252
 253 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
 254 {
 255         return vaddr_page(req->pages[seg]);
 256 }
 257
 258 static void scsiback_print_status(char *sense_buffer, int errors,
 259                                         struct vscsibk_pend *pending_req)
 260 {
 261         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 262
 263         pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
 264                tpg->tport->tport_name, pending_req->v2p->lun,
 265                pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
 266                host_byte(errors), driver_byte(errors));
 267 }
 268
 269 static void scsiback_fast_flush_area(struct vscsibk_pend *req)
 270 {
 271         struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
 272         struct page *pages[VSCSI_GRANT_BATCH];
 273         unsigned int i, invcount = 0;
 274         grant_handle_t handle;
 275         int err;
 276
 277         kfree(req->sgl);
 278         req->sgl = NULL;
 279         req->n_sg = 0;
 280
 281         if (!req->n_grants)
 282                 return;
 283
 284         for (i = 0; i < req->n_grants; i++) {
 285                 handle = req->grant_handles[i];
 286                 if (handle == SCSIBACK_INVALID_HANDLE)
 287                         continue;
 288                 gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
 289                                     GNTMAP_host_map, handle);
 290                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 291                 pages[invcount] = req->pages[i];
 292                 put_page(pages[invcount]);
 293                 invcount++;
 294                 if (invcount < VSCSI_GRANT_BATCH)
 295                         continue;
 296                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 297                 BUG_ON(err);
 298                 invcount = 0;
 299         }
 300
 301         if (invcount) {
 302                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 303                 BUG_ON(err);
 304         }
 305
 306         put_free_pages(req->pages, req->n_grants);
 307         req->n_grants = 0;
 308 }
 309
 310 static void scsiback_free_translation_entry(struct kref *kref)
 311 {
 312         struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
 313         struct scsiback_tpg *tpg = entry->tpg;
 314
 315         mutex_lock(&tpg->tv_tpg_mutex);
 316         tpg->tv_tpg_fe_count--;
 317         mutex_unlock(&tpg->tv_tpg_mutex);
 318
 319         kfree(entry);
 320 }
 321
 322 static void scsiback_send_response(struct vscsibk_info *info,
 323                         char *sense_buffer, int32_t result, uint32_t resid,
 324                         uint16_t rqid)
 325 {
 326         struct vscsiif_response *ring_res;
 327         int notify;
 328         struct scsi_sense_hdr sshdr;
 329         unsigned long flags;
 330         unsigned len;
 331
 332         spin_lock_irqsave(&info->ring_lock, flags);
 333
 334         ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
 335         info->ring.rsp_prod_pvt++;
 336
 337         ring_res->rslt   = result;
 338         ring_res->rqid   = rqid;
 339
 340         if (sense_buffer != NULL &&
 341             scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
 342                                  &sshdr)) {
 343                 len = min_t(unsigned, 8 + sense_buffer[7],
 344                             VSCSIIF_SENSE_BUFFERSIZE);
 345                 memcpy(ring_res->sense_buffer, sense_buffer, len);
 346                 ring_res->sense_len = len;
 347         } else {
 348                 ring_res->sense_len = 0;
 349         }
 350
 351         ring_res->residual_len = resid;
 352
 353         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
 354         spin_unlock_irqrestore(&info->ring_lock, flags);
 355
 356         if (notify)
 357                 notify_remote_via_irq(info->irq);
 358 }
 359
 360 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
 361                         uint32_t resid, struct vscsibk_pend *pending_req)
 362 {
 363         scsiback_send_response(pending_req->info, sense_buffer, result,
 364                                resid, pending_req->rqid);
 365
 366         if (pending_req->v2p)
 367                 kref_put(&pending_req->v2p->kref,
 368                          scsiback_free_translation_entry);
 369 }
 370
 371 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
 372 {
 373         struct vscsibk_info *info = pending_req->info;
 374         unsigned char *sense_buffer;
 375         unsigned int resid;
 376         int errors;
 377
 378         sense_buffer = pending_req->sense_buffer;
 379         resid        = pending_req->se_cmd.residual_count;
 380         errors       = pending_req->result;
 381
 382         if (errors && log_print_stat)
 383                 scsiback_print_status(sense_buffer, errors, pending_req);
 384
 385         scsiback_fast_flush_area(pending_req);
 386         scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
 387         scsiback_put(info);
 388         /*
 389          * Drop the extra KREF_ACK reference taken by target_submit_cmd_map_sgls()
 390          * ahead of scsiback_check_stop_free() ->  transport_generic_free_cmd()
 391          * final se_cmd->cmd_kref put.
 392          */
 393         target_put_sess_cmd(&pending_req->se_cmd);
 394 }
 395
 396 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
 397 {
 398         struct se_cmd *se_cmd = &pending_req->se_cmd;
 399         struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
 400         int rc;
 401
 402         scsiback_get(pending_req->info);
 403         se_cmd->tag = pending_req->rqid;
 404         rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,
 405                         pending_req->sense_buffer, pending_req->v2p->lun,
 406                         pending_req->data_len, 0,
 407                         pending_req->sc_data_direction, TARGET_SCF_ACK_KREF,
 408                         pending_req->sgl, pending_req->n_sg,
 409                         NULL, 0, NULL, 0);
 410         if (rc < 0) {
 411                 transport_send_check_condition_and_sense(se_cmd,
 412                                 TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
 413                 transport_generic_free_cmd(se_cmd, 0);
 414         }
 415 }
 416
 417 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 418         struct page **pg, grant_handle_t *grant, int cnt)
 419 {
 420         int err, i;
 421
 422         if (!cnt)
 423                 return 0;
 424
 425         err = gnttab_map_refs(map, NULL, pg, cnt);
 426         BUG_ON(err);
 427         for (i = 0; i < cnt; i++) {
 428                 if (unlikely(map[i].status != GNTST_okay)) {
 429                         pr_err("invalid buffer -- could not remap it\n");
 430                         map[i].handle = SCSIBACK_INVALID_HANDLE;
 431                         err = -ENOMEM;
 432                 } else {
 433                         get_page(pg[i]);
 434                 }
 435                 grant[i] = map[i].handle;
 436         }
 437         return err;
 438 }
 439
 440 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
 441                         struct scsiif_request_segment *seg, struct page **pg,
 442                         grant_handle_t *grant, int cnt, u32 flags)
 443 {
 444         int mapcount = 0, i, err = 0;
 445         struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
 446         struct vscsibk_info *info = pending_req->info;
 447
 448         for (i = 0; i < cnt; i++) {
 449                 if (get_free_page(pg + mapcount)) {
 450                         put_free_pages(pg, mapcount);
 451                         pr_err("no grant page\n");
 452                         return -ENOMEM;
 453                 }
 454                 gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
 455                                   flags, seg[i].gref, info->domid);
 456                 mapcount++;
 457                 if (mapcount < VSCSI_GRANT_BATCH)
 458                         continue;
 459                 err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 460                 pg += mapcount;
 461                 grant += mapcount;
 462                 pending_req->n_grants += mapcount;
 463                 if (err)
 464                         return err;
 465                 mapcount = 0;
 466         }
 467         err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 468         pending_req->n_grants += mapcount;
 469         return err;
 470 }
 471
 472 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 473                                         struct vscsibk_pend *pending_req)
 474 {
 475         u32 flags;
 476         int i, err, n_segs, i_seg = 0;
 477         struct page **pg;
 478         struct scsiif_request_segment *seg;
 479         unsigned long end_seg = 0;
 480         unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
 481         unsigned int nr_sgl = 0;
 482         struct scatterlist *sg;
 483         grant_handle_t *grant;
 484
 485         pending_req->n_sg = 0;
 486         pending_req->n_grants = 0;
 487         pending_req->data_len = 0;
 488
 489         nr_segments &= ~VSCSIIF_SG_GRANT;
 490         if (!nr_segments)
 491                 return 0;
 492
 493         if (nr_segments > VSCSIIF_SG_TABLESIZE) {
 494                 pr_debug("invalid parameter nr_seg = %d\n",
 495                         ring_req->nr_segments);
 496                 return -EINVAL;
 497         }
 498
 499         if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
 500                 err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
 501                         pending_req->pages, pending_req->grant_handles,
 502                         nr_segments, GNTMAP_host_map | GNTMAP_readonly);
 503                 if (err)
 504                         return err;
 505                 nr_sgl = nr_segments;
 506                 nr_segments = 0;
 507                 for (i = 0; i < nr_sgl; i++) {
 508                         n_segs = ring_req->seg[i].length /
 509                                  sizeof(struct scsiif_request_segment);
 510                         if ((unsigned)ring_req->seg[i].offset +
 511                             (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
 512                             n_segs * sizeof(struct scsiif_request_segment) !=
 513                             ring_req->seg[i].length)
 514                                 return -EINVAL;
 515                         nr_segments += n_segs;
 516                 }
 517                 if (nr_segments > SG_ALL) {
 518                         pr_debug("invalid nr_seg = %d\n", nr_segments);
 519                         return -EINVAL;
 520                 }
 521         }
 522
 523         /* free of (sgl) in fast_flush_area() */
 524         pending_req->sgl = kmalloc_array(nr_segments,
 525                                         sizeof(struct scatterlist), GFP_KERNEL);
 526         if (!pending_req->sgl)
 527                 return -ENOMEM;
 528
 529         sg_init_table(pending_req->sgl, nr_segments);
 530         pending_req->n_sg = nr_segments;
 531
 532         flags = GNTMAP_host_map;
 533         if (pending_req->sc_data_direction == DMA_TO_DEVICE)
 534                 flags |= GNTMAP_readonly;
 535
 536         pg = pending_req->pages + nr_sgl;
 537         grant = pending_req->grant_handles + nr_sgl;
 538         if (!nr_sgl) {
 539                 seg = ring_req->seg;
 540                 err = scsiback_gnttab_data_map_list(pending_req, seg,
 541                         pg, grant, nr_segments, flags);
 542                 if (err)
 543                         return err;
 544         } else {
 545                 for (i = 0; i < nr_sgl; i++) {
 546                         seg = (struct scsiif_request_segment *)(
 547                               vaddr(pending_req, i) + ring_req->seg[i].offset);
 548                         n_segs = ring_req->seg[i].length /
 549                                  sizeof(struct scsiif_request_segment);
 550                         err = scsiback_gnttab_data_map_list(pending_req, seg,
 551                                 pg, grant, n_segs, flags);
 552                         if (err)
 553                                 return err;
 554                         pg += n_segs;
 555                         grant += n_segs;
 556                 }
 557                 end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
 558                 seg = (struct scsiif_request_segment *)end_seg;
 559                 end_seg += ring_req->seg[0].length;
 560                 pg = pending_req->pages + nr_sgl;
 561         }
 562
 563         for_each_sg(pending_req->sgl, sg, nr_segments, i) {
 564                 sg_set_page(sg, pg[i], seg->length, seg->offset);
 565                 pending_req->data_len += seg->length;
 566                 seg++;
 567                 if (nr_sgl && (unsigned long)seg >= end_seg) {
 568                         i_seg++;
 569                         end_seg = vaddr(pending_req, i_seg) +
 570                                   ring_req->seg[i_seg].offset;
 571                         seg = (struct scsiif_request_segment *)end_seg;
 572                         end_seg += ring_req->seg[i_seg].length;
 573                 }
 574                 if (sg->offset >= PAGE_SIZE ||
 575                     sg->length > PAGE_SIZE ||
 576                     sg->offset + sg->length > PAGE_SIZE)
 577                         return -EINVAL;
 578         }
 579
 580         return 0;
 581 }
 582
 583 static void scsiback_disconnect(struct vscsibk_info *info)
 584 {
 585         wait_event(info->waiting_to_free,
 586                 atomic_read(&info->nr_unreplied_reqs) == 0);
 587
 588         unbind_from_irqhandler(info->irq, info);
 589         info->irq = 0;
 590         xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
 591 }
 592
 593 static void scsiback_device_action(struct vscsibk_pend *pending_req,
 594         enum tcm_tmreq_table act, int tag)
 595 {
 596         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 597         struct scsiback_nexus *nexus = tpg->tpg_nexus;
 598         struct se_cmd *se_cmd = &pending_req->se_cmd;
 599         u64 unpacked_lun = pending_req->v2p->lun;
 600         int rc, err = FAILED;
 601
 602         init_completion(&pending_req->tmr_done);
 603
 604         rc = target_submit_tmr(&pending_req->se_cmd, nexus->tvn_se_sess,
 605                                &pending_req->sense_buffer[0],
 606                                unpacked_lun, NULL, act, GFP_KERNEL,
 607                                tag, TARGET_SCF_ACK_KREF);
 608         if (rc)
 609                 goto err;
 610
 611         wait_for_completion(&pending_req->tmr_done);
 612
 613         err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
 614                 SUCCESS : FAILED;
 615
 616         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 617         transport_generic_free_cmd(&pending_req->se_cmd, 0);
 618         return;
 619
 620 err:
 621         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 622 }
 623
 624 /*
 625   Perform virtual to physical translation
 626 */
 627 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
 628                         struct ids_tuple *v)
 629 {
 630         struct v2p_entry *entry;
 631         struct list_head *head = &(info->v2p_entry_lists);
 632         unsigned long flags;
 633
 634         spin_lock_irqsave(&info->v2p_lock, flags);
 635         list_for_each_entry(entry, head, l) {
 636                 if ((entry->v.chn == v->chn) &&
 637                     (entry->v.tgt == v->tgt) &&
 638                     (entry->v.lun == v->lun)) {
 639                         kref_get(&entry->kref);
 640                         goto out;
 641                 }
 642         }
 643         entry = NULL;
 644
 645 out:
 646         spin_unlock_irqrestore(&info->v2p_lock, flags);
 647         return entry;
 648 }
 649
 650 static struct vscsibk_pend *scsiback_get_pend_req(struct vscsiif_back_ring *ring,
 651                                 struct v2p_entry *v2p)
 652 {
 653         struct scsiback_tpg *tpg = v2p->tpg;
 654         struct scsiback_nexus *nexus = tpg->tpg_nexus;
 655         struct se_session *se_sess = nexus->tvn_se_sess;
 656         struct vscsibk_pend *req;
 657         int tag, cpu, i;
 658
 659         tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
 660         if (tag < 0) {
 661                 pr_err("Unable to obtain tag for vscsiif_request\n");
 662                 return ERR_PTR(-ENOMEM);
 663         }
 664
 665         req = &((struct vscsibk_pend *)se_sess->sess_cmd_map)[tag];
 666         memset(req, 0, sizeof(*req));
 667         req->se_cmd.map_tag = tag;
 668         req->se_cmd.map_cpu = cpu;
 669
 670         for (i = 0; i < VSCSI_MAX_GRANTS; i++)
 671                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 672
 673         return req;
 674 }
 675
 676 static struct vscsibk_pend *prepare_pending_reqs(struct vscsibk_info *info,
 677                                 struct vscsiif_back_ring *ring,
 678                                 struct vscsiif_request *ring_req)
 679 {
 680         struct vscsibk_pend *pending_req;
 681         struct v2p_entry *v2p;
 682         struct ids_tuple vir;
 683
 684         /* request range check from frontend */
 685         if ((ring_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
 686                 (ring_req->sc_data_direction != DMA_TO_DEVICE) &&
 687                 (ring_req->sc_data_direction != DMA_FROM_DEVICE) &&
 688                 (ring_req->sc_data_direction != DMA_NONE)) {
 689                 pr_debug("invalid parameter data_dir = %d\n",
 690                         ring_req->sc_data_direction);
 691                 return ERR_PTR(-EINVAL);
 692         }
 693         if (ring_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
 694                 pr_debug("invalid parameter cmd_len = %d\n",
 695                         ring_req->cmd_len);
 696                 return ERR_PTR(-EINVAL);
 697         }
 698
 699         vir.chn = ring_req->channel;
 700         vir.tgt = ring_req->id;
 701         vir.lun = ring_req->lun;
 702
 703         v2p = scsiback_do_translation(info, &vir);
 704         if (!v2p) {
 705                 pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
 706                          vir.chn, vir.tgt, vir.lun);
 707                 return ERR_PTR(-ENODEV);
 708         }
 709
 710         pending_req = scsiback_get_pend_req(ring, v2p);
 711         if (IS_ERR(pending_req)) {
 712                 kref_put(&v2p->kref, scsiback_free_translation_entry);
 713                 return ERR_PTR(-ENOMEM);
 714         }
 715         pending_req->rqid = ring_req->rqid;
 716         pending_req->info = info;
 717         pending_req->v2p = v2p;
 718         pending_req->sc_data_direction = ring_req->sc_data_direction;
 719         pending_req->cmd_len = ring_req->cmd_len;
 720         memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
 721
 722         return pending_req;
 723 }
 724
 725 static int scsiback_do_cmd_fn(struct vscsibk_info *info)
 726 {
 727         struct vscsiif_back_ring *ring = &info->ring;
 728         struct vscsiif_request ring_req;
 729         struct vscsibk_pend *pending_req;
 730         RING_IDX rc, rp;
 731         int more_to_do;
 732         uint32_t result;
 733
 734         rc = ring->req_cons;
 735         rp = ring->sring->req_prod;
 736         rmb();  /* guest system is accessing ring, too */
 737
 738         if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
 739                 rc = ring->rsp_prod_pvt;
 740                 pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 741                            info->domid, rp, rc, rp - rc);
 742                 info->ring_error = 1;
 743                 return 0;
 744         }
 745
 746         while ((rc != rp)) {
 747                 if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
 748                         break;
 749
 750                 RING_COPY_REQUEST(ring, rc, &ring_req);
 751                 ring->req_cons = ++rc;
 752
 753                 pending_req = prepare_pending_reqs(info, ring, &ring_req);
 754                 if (IS_ERR(pending_req)) {
 755                         switch (PTR_ERR(pending_req)) {
 756                         case -ENODEV:
 757                                 result = DID_NO_CONNECT;
 758                                 break;
 759                         default:
 760                                 result = DRIVER_ERROR;
 761                                 break;
 762                         }
 763                         scsiback_send_response(info, NULL, result << 24, 0,
 764                                                ring_req.rqid);
 765                         return 1;
 766                 }
 767
 768                 switch (ring_req.act) {
 769                 case VSCSIIF_ACT_SCSI_CDB:
 770                         if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
 771                                 scsiback_fast_flush_area(pending_req);
 772                                 scsiback_do_resp_with_sense(NULL,
 773                                                 DRIVER_ERROR << 24, 0, pending_req);
 774                                 transport_generic_free_cmd(&pending_req->se_cmd, 0);
 775                         } else {
 776                                 scsiback_cmd_exec(pending_req);
 777                         }
 778                         break;
 779                 case VSCSIIF_ACT_SCSI_ABORT:
 780                         scsiback_device_action(pending_req, TMR_ABORT_TASK,
 781                                 ring_req.ref_rqid);
 782                         break;
 783                 case VSCSIIF_ACT_SCSI_RESET:
 784                         scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
 785                         break;
 786                 default:
 787                         pr_err_ratelimited("invalid request\n");
 788                         scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24, 0,
 789                                                     pending_req);
 790                         transport_generic_free_cmd(&pending_req->se_cmd, 0);
 791                         break;
 792                 }
 793
 794                 /* Yield point for this unbounded loop. */
 795                 cond_resched();
 796         }
 797
 798         RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
 799         return more_to_do;
 800 }
 801
 802 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
 803 {
 804         struct vscsibk_info *info = dev_id;
 805
 806         if (info->ring_error)
 807                 return IRQ_HANDLED;
 808
 809         while (scsiback_do_cmd_fn(info))
 810                 cond_resched();
 811
 812         return IRQ_HANDLED;
 813 }
 814
 815 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 816                         evtchn_port_t evtchn)
 817 {
 818         void *area;
 819         struct vscsiif_sring *sring;
 820         int err;
 821
 822         if (info->irq)
 823                 return -1;
 824
 825         err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 826         if (err)
 827                 return err;
 828
 829         sring = (struct vscsiif_sring *)area;
 830         BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 831
 832         err = bind_interdomain_evtchn_to_irq(info->domid, evtchn);
 833         if (err < 0)
 834                 goto unmap_page;
 835
 836         info->irq = err;
 837
 838         err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
 839                                    IRQF_ONESHOT, "vscsiif-backend", info);
 840         if (err)
 841                 goto free_irq;
 842
 843         return 0;
 844
 845 free_irq:
 846         unbind_from_irqhandler(info->irq, info);
 847         info->irq = 0;
 848 unmap_page:
 849         xenbus_unmap_ring_vfree(info->dev, area);
 850
 851         return err;
 852 }
 853
 854 static int scsiback_map(struct vscsibk_info *info)
 855 {
 856         struct xenbus_device *dev = info->dev;
 857         unsigned int ring_ref;
 858         evtchn_port_t evtchn;
 859         int err;
 860
 861         err = xenbus_gather(XBT_NIL, dev->otherend,
 862                         "ring-ref", "%u", &ring_ref,
 863                         "event-channel", "%u", &evtchn, NULL);
 864         if (err) {
 865                 xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
 866                 return err;
 867         }
 868
 869         return scsiback_init_sring(info, ring_ref, evtchn);
 870 }
 871
 872 /*
 873   Check for a translation entry being present
 874 */
 875 static struct v2p_entry *scsiback_chk_translation_entry(
 876         struct vscsibk_info *info, struct ids_tuple *v)
 877 {
 878         struct list_head *head = &(info->v2p_entry_lists);
 879         struct v2p_entry *entry;
 880
 881         list_for_each_entry(entry, head, l)
 882                 if ((entry->v.chn == v->chn) &&
 883                     (entry->v.tgt == v->tgt) &&
 884                     (entry->v.lun == v->lun))
 885                         return entry;
 886
 887         return NULL;
 888 }
 889
 890 /*
 891   Add a new translation entry
 892 */
 893 static int scsiback_add_translation_entry(struct vscsibk_info *info,
 894                                           char *phy, struct ids_tuple *v)
 895 {
 896         int err = 0;
 897         struct v2p_entry *new;
 898         unsigned long flags;
 899         char *lunp;
 900         unsigned long long unpacked_lun;
 901         struct se_lun *se_lun;
 902         struct scsiback_tpg *tpg_entry, *tpg = NULL;
 903         char *error = "doesn't exist";
 904
 905         lunp = strrchr(phy, ':');
 906         if (!lunp) {
 907                 pr_err("illegal format of physical device %s\n", phy);
 908                 return -EINVAL;
 909         }
 910         *lunp = 0;
 911         lunp++;
 912         err = kstrtoull(lunp, 10, &unpacked_lun);
 913         if (err < 0) {
 914                 pr_err("lun number not valid: %s\n", lunp);
 915                 return err;
 916         }
 917
 918         mutex_lock(&scsiback_mutex);
 919         list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
 920                 if (!strcmp(phy, tpg_entry->tport->tport_name) ||
 921                     !strcmp(phy, tpg_entry->param_alias)) {
 922                         mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
 923                         hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
 924                                 if (se_lun->unpacked_lun == unpacked_lun) {
 925                                         if (!tpg_entry->tpg_nexus)
 926                                                 error = "nexus undefined";
 927                                         else
 928                                                 tpg = tpg_entry;
 929                                         break;
 930                                 }
 931                         }
 932                         mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
 933                         break;
 934                 }
 935         }
 936         if (tpg) {
 937                 mutex_lock(&tpg->tv_tpg_mutex);
 938                 tpg->tv_tpg_fe_count++;
 939                 mutex_unlock(&tpg->tv_tpg_mutex);
 940         }
 941         mutex_unlock(&scsiback_mutex);
 942
 943         if (!tpg) {
 944                 pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
 945                 return -ENODEV;
 946         }
 947
 948         new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
 949         if (new == NULL) {
 950                 err = -ENOMEM;
 951                 goto out_free;
 952         }
 953
 954         spin_lock_irqsave(&info->v2p_lock, flags);
 955
 956         /* Check double assignment to identical virtual ID */
 957         if (scsiback_chk_translation_entry(info, v)) {
 958                 pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 959                 err = -EEXIST;
 960                 goto out;
 961         }
 962
 963         /* Create a new translation entry and add to the list */
 964         kref_init(&new->kref);
 965         new->v = *v;
 966         new->tpg = tpg;
 967         new->lun = unpacked_lun;
 968         list_add_tail(&new->l, &info->v2p_entry_lists);
 969
 970 out:
 971         spin_unlock_irqrestore(&info->v2p_lock, flags);
 972
 973 out_free:
 974         if (err) {
 975                 mutex_lock(&tpg->tv_tpg_mutex);
 976                 tpg->tv_tpg_fe_count--;
 977                 mutex_unlock(&tpg->tv_tpg_mutex);
 978                 kfree(new);
 979         }
 980
 981         return err;
 982 }
 983
 984 static void __scsiback_del_translation_entry(struct v2p_entry *entry)
 985 {
 986         list_del(&entry->l);
 987         kref_put(&entry->kref, scsiback_free_translation_entry);
 988 }
 989
 990 /*
 991   Delete the translation entry specified
 992 */
 993 static int scsiback_del_translation_entry(struct vscsibk_info *info,
 994                                           struct ids_tuple *v)
 995 {
 996         struct v2p_entry *entry;
 997         unsigned long flags;
 998         int ret = 0;
 999
1000         spin_lock_irqsave(&info->v2p_lock, flags);
1001         /* Find out the translation entry specified */
1002         entry = scsiback_chk_translation_entry(info, v);
1003         if (entry)
1004                 __scsiback_del_translation_entry(entry);
1005         else
1006                 ret = -ENOENT;
1007
1008         spin_unlock_irqrestore(&info->v2p_lock, flags);
1009         return ret;
1010 }
1011
1012 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
1013                                 char *phy, struct ids_tuple *vir, int try)
1014 {
1015         struct v2p_entry *entry;
1016         unsigned long flags;
1017         int err;
1018
1019         if (try) {
1020                 spin_lock_irqsave(&info->v2p_lock, flags);
1021                 entry = scsiback_chk_translation_entry(info, vir);
1022                 spin_unlock_irqrestore(&info->v2p_lock, flags);
1023                 if (entry)
1024                         return;
1025         }
1026         if (!scsiback_add_translation_entry(info, phy, vir)) {
1027                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1028                                   "%d", XenbusStateInitialised)) {
1029                         pr_err("xenbus_printf error %s\n", state);
1030                         scsiback_del_translation_entry(info, vir);
1031                 }
1032         } else if (!try) {
1033                 err = xenbus_printf(XBT_NIL, info->dev->nodename, state,
1034                               "%d", XenbusStateClosed);
1035                 if (err)
1036                         xenbus_dev_error(info->dev, err,
1037                                 "%s: writing %s", __func__, state);
1038         }
1039 }
1040
1041 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1042                                 struct ids_tuple *vir)
1043 {
1044         if (!scsiback_del_translation_entry(info, vir)) {
1045                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1046                                   "%d", XenbusStateClosed))
1047                         pr_err("xenbus_printf error %s\n", state);
1048         }
1049 }
1050
1051 #define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1052 #define VSCSIBACK_OP_UPDATEDEV_STATE    2
1053
1054 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1055                                      char *ent)
1056 {
1057         int err;
1058         struct ids_tuple vir;
1059         char *val;
1060         int device_state;
1061         char phy[VSCSI_NAMELEN];
1062         char str[64];
1063         char state[64];
1064         struct xenbus_device *dev = info->dev;
1065
1066         /* read status */
1067         snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1068         err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1069         if (XENBUS_EXIST_ERR(err))
1070                 return;
1071
1072         /* physical SCSI device */
1073         snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1074         val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1075         if (IS_ERR(val)) {
1076                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1077                               "%d", XenbusStateClosed);
1078                 if (err)
1079                         xenbus_dev_error(info->dev, err,
1080                                 "%s: writing %s", __func__, state);
1081                 return;
1082         }
1083         strlcpy(phy, val, VSCSI_NAMELEN);
1084         kfree(val);
1085
1086         /* virtual SCSI device */
1087         snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1088         err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1089                            &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1090         if (XENBUS_EXIST_ERR(err)) {
1091                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1092                               "%d", XenbusStateClosed);
1093                 if (err)
1094                         xenbus_dev_error(info->dev, err,
1095                                 "%s: writing %s", __func__, state);
1096                 return;
1097         }
1098
1099         switch (op) {
1100         case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1101                 switch (device_state) {
1102                 case XenbusStateInitialising:
1103                         scsiback_do_add_lun(info, state, phy, &vir, 0);
1104                         break;
1105                 case XenbusStateConnected:
1106                         scsiback_do_add_lun(info, state, phy, &vir, 1);
1107                         break;
1108                 case XenbusStateClosing:
1109                         scsiback_do_del_lun(info, state, &vir);
1110                         break;
1111                 default:
1112                         break;
1113                 }
1114                 break;
1115
1116         case VSCSIBACK_OP_UPDATEDEV_STATE:
1117                 if (device_state == XenbusStateInitialised) {
1118                         /* modify vscsi-devs/dev-x/state */
1119                         if (xenbus_printf(XBT_NIL, dev->nodename, state,
1120                                           "%d", XenbusStateConnected)) {
1121                                 pr_err("xenbus_printf error %s\n", str);
1122                                 scsiback_del_translation_entry(info, &vir);
1123                                 xenbus_printf(XBT_NIL, dev->nodename, state,
1124                                               "%d", XenbusStateClosed);
1125                         }
1126                 }
1127                 break;
1128         /* When it is necessary, processing is added here. */
1129         default:
1130                 break;
1131         }
1132 }
1133
1134 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1135 {
1136         int i;
1137         char **dir;
1138         unsigned int ndir = 0;
1139
1140         dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1141                                &ndir);
1142         if (IS_ERR(dir))
1143                 return;
1144
1145         for (i = 0; i < ndir; i++)
1146                 scsiback_do_1lun_hotplug(info, op, dir[i]);
1147
1148         kfree(dir);
1149 }
1150
1151 static void scsiback_frontend_changed(struct xenbus_device *dev,
1152                                         enum xenbus_state frontend_state)
1153 {
1154         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1155
1156         switch (frontend_state) {
1157         case XenbusStateInitialising:
1158                 break;
1159
1160         case XenbusStateInitialised:
1161                 if (scsiback_map(info))
1162                         break;
1163
1164                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1165                 xenbus_switch_state(dev, XenbusStateConnected);
1166                 break;
1167
1168         case XenbusStateConnected:
1169                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1170
1171                 if (dev->state == XenbusStateConnected)
1172                         break;
1173
1174                 xenbus_switch_state(dev, XenbusStateConnected);
1175                 break;
1176
1177         case XenbusStateClosing:
1178                 if (info->irq)
1179                         scsiback_disconnect(info);
1180
1181                 xenbus_switch_state(dev, XenbusStateClosing);
1182                 break;
1183
1184         case XenbusStateClosed:
1185                 xenbus_switch_state(dev, XenbusStateClosed);
1186                 if (xenbus_dev_is_online(dev))
1187                         break;
1188                 fallthrough;    /* if not online */
1189         case XenbusStateUnknown:
1190                 device_unregister(&dev->dev);
1191                 break;
1192
1193         case XenbusStateReconfiguring:
1194                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1195                 xenbus_switch_state(dev, XenbusStateReconfigured);
1196
1197                 break;
1198
1199         default:
1200                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1201                                         frontend_state);
1202                 break;
1203         }
1204 }
1205
1206 /*
1207   Release the translation entry specfied
1208 */
1209 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1210 {
1211         struct v2p_entry *entry, *tmp;
1212         struct list_head *head = &(info->v2p_entry_lists);
1213         unsigned long flags;
1214
1215         spin_lock_irqsave(&info->v2p_lock, flags);
1216
1217         list_for_each_entry_safe(entry, tmp, head, l)
1218                 __scsiback_del_translation_entry(entry);
1219
1220         spin_unlock_irqrestore(&info->v2p_lock, flags);
1221 }
1222
1223 static int scsiback_remove(struct xenbus_device *dev)
1224 {
1225         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1226
1227         if (info->irq)
1228                 scsiback_disconnect(info);
1229
1230         scsiback_release_translation_entry(info);
1231
1232         dev_set_drvdata(&dev->dev, NULL);
1233
1234         return 0;
1235 }
1236
1237 static int scsiback_probe(struct xenbus_device *dev,
1238                            const struct xenbus_device_id *id)
1239 {
1240         int err;
1241
1242         struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1243                                             GFP_KERNEL);
1244
1245         pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1246
1247         if (!info) {
1248                 xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1249                 return -ENOMEM;
1250         }
1251         info->dev = dev;
1252         dev_set_drvdata(&dev->dev, info);
1253
1254         info->domid = dev->otherend_id;
1255         spin_lock_init(&info->ring_lock);
1256         info->ring_error = 0;
1257         atomic_set(&info->nr_unreplied_reqs, 0);
1258         init_waitqueue_head(&info->waiting_to_free);
1259         info->dev = dev;
1260         info->irq = 0;
1261         INIT_LIST_HEAD(&info->v2p_entry_lists);
1262         spin_lock_init(&info->v2p_lock);
1263
1264         err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1265                             SG_ALL);
1266         if (err)
1267                 xenbus_dev_error(dev, err, "writing feature-sg-grant");
1268
1269         err = xenbus_switch_state(dev, XenbusStateInitWait);
1270         if (err)
1271                 goto fail;
1272
1273         return 0;
1274
1275 fail:
1276         pr_warn("%s failed\n", __func__);
1277         scsiback_remove(dev);
1278
1279         return err;
1280 }
1281
1282 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1283 {
1284         switch (tport->tport_proto_id) {
1285         case SCSI_PROTOCOL_SAS:
1286                 return "SAS";
1287         case SCSI_PROTOCOL_FCP:
1288                 return "FCP";
1289         case SCSI_PROTOCOL_ISCSI:
1290                 return "iSCSI";
1291         default:
1292                 break;
1293         }
1294
1295         return "Unknown";
1296 }
1297
1298 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1299 {
1300         struct scsiback_tpg *tpg = container_of(se_tpg,
1301                                 struct scsiback_tpg, se_tpg);
1302         struct scsiback_tport *tport = tpg->tport;
1303
1304         return &tport->tport_name[0];
1305 }
1306
1307 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1308 {
1309         struct scsiback_tpg *tpg = container_of(se_tpg,
1310                                 struct scsiback_tpg, se_tpg);
1311         return tpg->tport_tpgt;
1312 }
1313
1314 static struct se_wwn *
1315 scsiback_make_tport(struct target_fabric_configfs *tf,
1316                      struct config_group *group,
1317                      const char *name)
1318 {
1319         struct scsiback_tport *tport;
1320         char *ptr;
1321         u64 wwpn = 0;
1322         int off = 0;
1323
1324         tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1325         if (!tport)
1326                 return ERR_PTR(-ENOMEM);
1327
1328         tport->tport_wwpn = wwpn;
1329         /*
1330          * Determine the emulated Protocol Identifier and Target Port Name
1331          * based on the incoming configfs directory name.
1332          */
1333         ptr = strstr(name, "naa.");
1334         if (ptr) {
1335                 tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1336                 goto check_len;
1337         }
1338         ptr = strstr(name, "fc.");
1339         if (ptr) {
1340                 tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1341                 off = 3; /* Skip over "fc." */
1342                 goto check_len;
1343         }
1344         ptr = strstr(name, "iqn.");
1345         if (ptr) {
1346                 tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1347                 goto check_len;
1348         }
1349
1350         pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1351         kfree(tport);
1352         return ERR_PTR(-EINVAL);
1353
1354 check_len:
1355         if (strlen(name) >= VSCSI_NAMELEN) {
1356                 pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1357                         scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1358                 kfree(tport);
1359                 return ERR_PTR(-EINVAL);
1360         }
1361         snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1362
1363         pr_debug("Allocated emulated Target %s Address: %s\n",
1364                  scsiback_dump_proto_id(tport), name);
1365
1366         return &tport->tport_wwn;
1367 }
1368
1369 static void scsiback_drop_tport(struct se_wwn *wwn)
1370 {
1371         struct scsiback_tport *tport = container_of(wwn,
1372                                 struct scsiback_tport, tport_wwn);
1373
1374         pr_debug("Deallocating emulated Target %s Address: %s\n",
1375                  scsiback_dump_proto_id(tport), tport->tport_name);
1376
1377         kfree(tport);
1378 }
1379
1380 static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1381 {
1382         return 1;
1383 }
1384
1385 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1386 {
1387         return transport_generic_free_cmd(se_cmd, 0);
1388 }
1389
1390 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1391 {
1392         target_free_tag(se_cmd->se_sess, se_cmd);
1393 }
1394
1395 static u32 scsiback_sess_get_index(struct se_session *se_sess)
1396 {
1397         return 0;
1398 }
1399
1400 static int scsiback_write_pending(struct se_cmd *se_cmd)
1401 {
1402         /* Go ahead and process the write immediately */
1403         target_execute_cmd(se_cmd);
1404
1405         return 0;
1406 }
1407
1408 static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1409 {
1410 }
1411
1412 static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1413 {
1414         return 0;
1415 }
1416
1417 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1418 {
1419         struct vscsibk_pend *pending_req = container_of(se_cmd,
1420                                 struct vscsibk_pend, se_cmd);
1421
1422         pending_req->result = SAM_STAT_GOOD;
1423         scsiback_cmd_done(pending_req);
1424         return 0;
1425 }
1426
1427 static int scsiback_queue_status(struct se_cmd *se_cmd)
1428 {
1429         struct vscsibk_pend *pending_req = container_of(se_cmd,
1430                                 struct vscsibk_pend, se_cmd);
1431
1432         if (se_cmd->sense_buffer &&
1433             ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1434              (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1435                 pending_req->result = (DRIVER_SENSE << 24) |
1436                                       SAM_STAT_CHECK_CONDITION;
1437         else
1438                 pending_req->result = se_cmd->scsi_status;
1439
1440         scsiback_cmd_done(pending_req);
1441         return 0;
1442 }
1443
1444 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1445 {
1446         struct vscsibk_pend *pending_req = container_of(se_cmd,
1447                                 struct vscsibk_pend, se_cmd);
1448
1449         complete(&pending_req->tmr_done);
1450 }
1451
1452 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1453 {
1454 }
1455
1456 static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1457                                              char *page)
1458 {
1459         struct se_portal_group *se_tpg = param_to_tpg(item);
1460         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1461                                                 se_tpg);
1462         ssize_t rb;
1463
1464         mutex_lock(&tpg->tv_tpg_mutex);
1465         rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1466         mutex_unlock(&tpg->tv_tpg_mutex);
1467
1468         return rb;
1469 }
1470
1471 static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1472                                               const char *page, size_t count)
1473 {
1474         struct se_portal_group *se_tpg = param_to_tpg(item);
1475         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1476                                                 se_tpg);
1477         int len;
1478
1479         if (strlen(page) >= VSCSI_NAMELEN) {
1480                 pr_err("param alias: %s, exceeds max: %d\n", page,
1481                         VSCSI_NAMELEN);
1482                 return -EINVAL;
1483         }
1484
1485         mutex_lock(&tpg->tv_tpg_mutex);
1486         len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1487         if (tpg->param_alias[len - 1] == '\n')
1488                 tpg->param_alias[len - 1] = '\0';
1489         mutex_unlock(&tpg->tv_tpg_mutex);
1490
1491         return count;
1492 }
1493
1494 CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1495
1496 static struct configfs_attribute *scsiback_param_attrs[] = {
1497         &scsiback_tpg_param_attr_alias,
1498         NULL,
1499 };
1500
1501 static int scsiback_alloc_sess_cb(struct se_portal_group *se_tpg,
1502                                   struct se_session *se_sess, void *p)
1503 {
1504         struct scsiback_tpg *tpg = container_of(se_tpg,
1505                                 struct scsiback_tpg, se_tpg);
1506
1507         tpg->tpg_nexus = p;
1508         return 0;
1509 }
1510
1511 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1512                                 const char *name)
1513 {
1514         struct scsiback_nexus *tv_nexus;
1515         int ret = 0;
1516
1517         mutex_lock(&tpg->tv_tpg_mutex);
1518         if (tpg->tpg_nexus) {
1519                 pr_debug("tpg->tpg_nexus already exists\n");
1520                 ret = -EEXIST;
1521                 goto out_unlock;
1522         }
1523
1524         tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1525         if (!tv_nexus) {
1526                 ret = -ENOMEM;
1527                 goto out_unlock;
1528         }
1529
1530         tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg,
1531                                                      VSCSI_DEFAULT_SESSION_TAGS,
1532                                                      sizeof(struct vscsibk_pend),
1533                                                      TARGET_PROT_NORMAL, name,
1534                                                      tv_nexus, scsiback_alloc_sess_cb);
1535         if (IS_ERR(tv_nexus->tvn_se_sess)) {
1536                 kfree(tv_nexus);
1537                 ret = -ENOMEM;
1538                 goto out_unlock;
1539         }
1540
1541 out_unlock:
1542         mutex_unlock(&tpg->tv_tpg_mutex);
1543         return ret;
1544 }
1545
1546 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1547 {
1548         struct se_session *se_sess;
1549         struct scsiback_nexus *tv_nexus;
1550
1551         mutex_lock(&tpg->tv_tpg_mutex);
1552         tv_nexus = tpg->tpg_nexus;
1553         if (!tv_nexus) {
1554                 mutex_unlock(&tpg->tv_tpg_mutex);
1555                 return -ENODEV;
1556         }
1557
1558         se_sess = tv_nexus->tvn_se_sess;
1559         if (!se_sess) {
1560                 mutex_unlock(&tpg->tv_tpg_mutex);
1561                 return -ENODEV;
1562         }
1563
1564         if (tpg->tv_tpg_port_count != 0) {
1565                 mutex_unlock(&tpg->tv_tpg_mutex);
1566                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1567                         tpg->tv_tpg_port_count);
1568                 return -EBUSY;
1569         }
1570
1571         if (tpg->tv_tpg_fe_count != 0) {
1572                 mutex_unlock(&tpg->tv_tpg_mutex);
1573                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1574                         tpg->tv_tpg_fe_count);
1575                 return -EBUSY;
1576         }
1577
1578         pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1579                 scsiback_dump_proto_id(tpg->tport),
1580                 tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1581
1582         /*
1583          * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1584          */
1585         target_remove_session(se_sess);
1586         tpg->tpg_nexus = NULL;
1587         mutex_unlock(&tpg->tv_tpg_mutex);
1588
1589         kfree(tv_nexus);
1590         return 0;
1591 }
1592
1593 static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1594 {
1595         struct se_portal_group *se_tpg = to_tpg(item);
1596         struct scsiback_tpg *tpg = container_of(se_tpg,
1597                                 struct scsiback_tpg, se_tpg);
1598         struct scsiback_nexus *tv_nexus;
1599         ssize_t ret;
1600
1601         mutex_lock(&tpg->tv_tpg_mutex);
1602         tv_nexus = tpg->tpg_nexus;
1603         if (!tv_nexus) {
1604                 mutex_unlock(&tpg->tv_tpg_mutex);
1605                 return -ENODEV;
1606         }
1607         ret = snprintf(page, PAGE_SIZE, "%s\n",
1608                         tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1609         mutex_unlock(&tpg->tv_tpg_mutex);
1610
1611         return ret;
1612 }
1613
1614 static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
1615                 const char *page, size_t count)
1616 {
1617         struct se_portal_group *se_tpg = to_tpg(item);
1618         struct scsiback_tpg *tpg = container_of(se_tpg,
1619                                 struct scsiback_tpg, se_tpg);
1620         struct scsiback_tport *tport_wwn = tpg->tport;
1621         unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1622         int ret;
1623         /*
1624          * Shutdown the active I_T nexus if 'NULL' is passed.
1625          */
1626         if (!strncmp(page, "NULL", 4)) {
1627                 ret = scsiback_drop_nexus(tpg);
1628                 return (!ret) ? count : ret;
1629         }
1630         /*
1631          * Otherwise make sure the passed virtual Initiator port WWN matches
1632          * the fabric protocol_id set in scsiback_make_tport(), and call
1633          * scsiback_make_nexus().
1634          */
1635         if (strlen(page) >= VSCSI_NAMELEN) {
1636                 pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1637                         page, VSCSI_NAMELEN);
1638                 return -EINVAL;
1639         }
1640         snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1641
1642         ptr = strstr(i_port, "naa.");
1643         if (ptr) {
1644                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1645                         pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1646                                 i_port, scsiback_dump_proto_id(tport_wwn));
1647                         return -EINVAL;
1648                 }
1649                 port_ptr = &i_port[0];
1650                 goto check_newline;
1651         }
1652         ptr = strstr(i_port, "fc.");
1653         if (ptr) {
1654                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1655                         pr_err("Passed FCP 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[3]; /* Skip over "fc." */
1660                 goto check_newline;
1661         }
1662         ptr = strstr(i_port, "iqn.");
1663         if (ptr) {
1664                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1665                         pr_err("Passed iSCSI 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[0];
1670                 goto check_newline;
1671         }
1672         pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1673                 i_port);
1674         return -EINVAL;
1675         /*
1676          * Clear any trailing newline for the NAA WWN
1677          */
1678 check_newline:
1679         if (i_port[strlen(i_port) - 1] == '\n')
1680                 i_port[strlen(i_port) - 1] = '\0';
1681
1682         ret = scsiback_make_nexus(tpg, port_ptr);
1683         if (ret < 0)
1684                 return ret;
1685
1686         return count;
1687 }
1688
1689 CONFIGFS_ATTR(scsiback_tpg_, nexus);
1690
1691 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1692         &scsiback_tpg_attr_nexus,
1693         NULL,
1694 };
1695
1696 static ssize_t
1697 scsiback_wwn_version_show(struct config_item *item, char *page)
1698 {
1699         return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1700                 UTS_RELEASE"\n",
1701                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1702 }
1703
1704 CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1705
1706 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1707         &scsiback_wwn_attr_version,
1708         NULL,
1709 };
1710
1711 static int scsiback_port_link(struct se_portal_group *se_tpg,
1712                                struct se_lun *lun)
1713 {
1714         struct scsiback_tpg *tpg = container_of(se_tpg,
1715                                 struct scsiback_tpg, se_tpg);
1716
1717         mutex_lock(&tpg->tv_tpg_mutex);
1718         tpg->tv_tpg_port_count++;
1719         mutex_unlock(&tpg->tv_tpg_mutex);
1720
1721         return 0;
1722 }
1723
1724 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1725                                   struct se_lun *lun)
1726 {
1727         struct scsiback_tpg *tpg = container_of(se_tpg,
1728                                 struct scsiback_tpg, se_tpg);
1729
1730         mutex_lock(&tpg->tv_tpg_mutex);
1731         tpg->tv_tpg_port_count--;
1732         mutex_unlock(&tpg->tv_tpg_mutex);
1733 }
1734
1735 static struct se_portal_group *
1736 scsiback_make_tpg(struct se_wwn *wwn, const char *name)
1737 {
1738         struct scsiback_tport *tport = container_of(wwn,
1739                         struct scsiback_tport, tport_wwn);
1740
1741         struct scsiback_tpg *tpg;
1742         u16 tpgt;
1743         int ret;
1744
1745         if (strstr(name, "tpgt_") != name)
1746                 return ERR_PTR(-EINVAL);
1747         ret = kstrtou16(name + 5, 10, &tpgt);
1748         if (ret)
1749                 return ERR_PTR(ret);
1750
1751         tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1752         if (!tpg)
1753                 return ERR_PTR(-ENOMEM);
1754
1755         mutex_init(&tpg->tv_tpg_mutex);
1756         INIT_LIST_HEAD(&tpg->tv_tpg_list);
1757         INIT_LIST_HEAD(&tpg->info_list);
1758         tpg->tport = tport;
1759         tpg->tport_tpgt = tpgt;
1760
1761         ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1762         if (ret < 0) {
1763                 kfree(tpg);
1764                 return NULL;
1765         }
1766         mutex_lock(&scsiback_mutex);
1767         list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1768         mutex_unlock(&scsiback_mutex);
1769
1770         return &tpg->se_tpg;
1771 }
1772
1773 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1774 {
1775         struct scsiback_tpg *tpg = container_of(se_tpg,
1776                                 struct scsiback_tpg, se_tpg);
1777
1778         mutex_lock(&scsiback_mutex);
1779         list_del(&tpg->tv_tpg_list);
1780         mutex_unlock(&scsiback_mutex);
1781         /*
1782          * Release the virtual I_T Nexus for this xen-pvscsi TPG
1783          */
1784         scsiback_drop_nexus(tpg);
1785         /*
1786          * Deregister the se_tpg from TCM.
1787          */
1788         core_tpg_deregister(se_tpg);
1789         kfree(tpg);
1790 }
1791
1792 static int scsiback_check_true(struct se_portal_group *se_tpg)
1793 {
1794         return 1;
1795 }
1796
1797 static int scsiback_check_false(struct se_portal_group *se_tpg)
1798 {
1799         return 0;
1800 }
1801
1802 static const struct target_core_fabric_ops scsiback_ops = {
1803         .module                         = THIS_MODULE,
1804         .fabric_name                    = "xen-pvscsi",
1805         .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1806         .tpg_get_tag                    = scsiback_get_tag,
1807         .tpg_check_demo_mode            = scsiback_check_true,
1808         .tpg_check_demo_mode_cache      = scsiback_check_true,
1809         .tpg_check_demo_mode_write_protect = scsiback_check_false,
1810         .tpg_check_prod_mode_write_protect = scsiback_check_false,
1811         .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1812         .check_stop_free                = scsiback_check_stop_free,
1813         .release_cmd                    = scsiback_release_cmd,
1814         .sess_get_index                 = scsiback_sess_get_index,
1815         .sess_get_initiator_sid         = NULL,
1816         .write_pending                  = scsiback_write_pending,
1817         .set_default_node_attributes    = scsiback_set_default_node_attrs,
1818         .get_cmd_state                  = scsiback_get_cmd_state,
1819         .queue_data_in                  = scsiback_queue_data_in,
1820         .queue_status                   = scsiback_queue_status,
1821         .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1822         .aborted_task                   = scsiback_aborted_task,
1823         /*
1824          * Setup callers for generic logic in target_core_fabric_configfs.c
1825          */
1826         .fabric_make_wwn                = scsiback_make_tport,
1827         .fabric_drop_wwn                = scsiback_drop_tport,
1828         .fabric_make_tpg                = scsiback_make_tpg,
1829         .fabric_drop_tpg                = scsiback_drop_tpg,
1830         .fabric_post_link               = scsiback_port_link,
1831         .fabric_pre_unlink              = scsiback_port_unlink,
1832
1833         .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1834         .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1835         .tfc_tpg_param_attrs            = scsiback_param_attrs,
1836 };
1837
1838 static const struct xenbus_device_id scsiback_ids[] = {
1839         { "vscsi" },
1840         { "" }
1841 };
1842
1843 static struct xenbus_driver scsiback_driver = {
1844         .ids                    = scsiback_ids,
1845         .probe                  = scsiback_probe,
1846         .remove                 = scsiback_remove,
1847         .otherend_changed       = scsiback_frontend_changed
1848 };
1849
1850 static int __init scsiback_init(void)
1851 {
1852         int ret;
1853
1854         if (!xen_domain())
1855                 return -ENODEV;
1856
1857         pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1858                  VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1859
1860         ret = xenbus_register_backend(&scsiback_driver);
1861         if (ret)
1862                 goto out;
1863
1864         ret = target_register_template(&scsiback_ops);
1865         if (ret)
1866                 goto out_unregister_xenbus;
1867
1868         return 0;
1869
1870 out_unregister_xenbus:
1871         xenbus_unregister_driver(&scsiback_driver);
1872 out:
1873         pr_err("%s: error %d\n", __func__, ret);
1874         return ret;
1875 }
1876
1877 static void __exit scsiback_exit(void)
1878 {
1879         struct page *page;
1880
1881         while (free_pages_num) {
1882                 if (get_free_page(&page))
1883                         BUG();
1884                 gnttab_free_pages(1, &page);
1885         }
1886         target_unregister_template(&scsiback_ops);
1887         xenbus_unregister_driver(&scsiback_driver);
1888 }
1889
1890 module_init(scsiback_init);
1891 module_exit(scsiback_exit);
1892
1893 MODULE_DESCRIPTION("Xen SCSI backend driver");
1894 MODULE_LICENSE("Dual BSD/GPL");
1895 MODULE_ALIAS("xen-backend:vscsi");
1896 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");