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.h>
  53 #include <scsi/scsi_dbg.h>
  54 #include <scsi/scsi_eh.h>
  55 #include <scsi/scsi_tcq.h>
  56
  57 #include <target/target_core_base.h>
  58 #include <target/target_core_fabric.h>
  59 #include <target/target_core_configfs.h>
  60 #include <target/target_core_fabric_configfs.h>
  61
  62 #include <asm/hypervisor.h>
  63
  64 #include <xen/xen.h>
  65 #include <xen/balloon.h>
  66 #include <xen/events.h>
  67 #include <xen/xenbus.h>
  68 #include <xen/grant_table.h>
  69 #include <xen/page.h>
  70
  71 #include <xen/interface/grant_table.h>
  72 #include <xen/interface/io/vscsiif.h>
  73
  74 #define VSCSI_VERSION   "v0.1"
  75 #define VSCSI_NAMELEN   32
  76
  77 struct ids_tuple {
  78         unsigned int hst;               /* host    */
  79         unsigned int chn;               /* channel */
  80         unsigned int tgt;               /* target  */
  81         unsigned int lun;               /* LUN     */
  82 };
  83
  84 struct v2p_entry {
  85         struct ids_tuple v;             /* translate from */
  86         struct scsiback_tpg *tpg;       /* translate to   */
  87         unsigned int lun;
  88         struct kref kref;
  89         struct list_head l;
  90 };
  91
  92 struct vscsibk_info {
  93         struct xenbus_device *dev;
  94
  95         domid_t domid;
  96         unsigned int irq;
  97
  98         struct vscsiif_back_ring ring;
  99         int ring_error;
 100
 101         spinlock_t ring_lock;
 102         atomic_t nr_unreplied_reqs;
 103
 104         spinlock_t v2p_lock;
 105         struct list_head v2p_entry_lists;
 106
 107         wait_queue_head_t waiting_to_free;
 108 };
 109
 110 /* theoretical maximum of grants for one request */
 111 #define VSCSI_MAX_GRANTS        (SG_ALL + VSCSIIF_SG_TABLESIZE)
 112
 113 /*
 114  * VSCSI_GRANT_BATCH is the maximum number of grants to be processed in one
 115  * call to map/unmap grants. Don't choose it too large, as there are arrays
 116  * with VSCSI_GRANT_BATCH elements allocated on the stack.
 117  */
 118 #define VSCSI_GRANT_BATCH       16
 119
 120 struct vscsibk_pend {
 121         uint16_t rqid;
 122
 123         uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE];
 124         uint8_t cmd_len;
 125
 126         uint8_t sc_data_direction;
 127         uint16_t n_sg;          /* real length of SG list */
 128         uint16_t n_grants;      /* SG pages and potentially SG list */
 129         uint32_t data_len;
 130         uint32_t result;
 131
 132         struct vscsibk_info *info;
 133         struct v2p_entry *v2p;
 134         struct scatterlist *sgl;
 135
 136         uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];
 137
 138         grant_handle_t grant_handles[VSCSI_MAX_GRANTS];
 139         struct page *pages[VSCSI_MAX_GRANTS];
 140
 141         struct se_cmd se_cmd;
 142 };
 143
 144 struct scsiback_tmr {
 145         atomic_t tmr_complete;
 146         wait_queue_head_t tmr_wait;
 147 };
 148
 149 struct scsiback_nexus {
 150         /* Pointer to TCM session for I_T Nexus */
 151         struct se_session *tvn_se_sess;
 152 };
 153
 154 struct scsiback_tport {
 155         /* SCSI protocol the tport is providing */
 156         u8 tport_proto_id;
 157         /* Binary World Wide unique Port Name for pvscsi Target port */
 158         u64 tport_wwpn;
 159         /* ASCII formatted WWPN for pvscsi Target port */
 160         char tport_name[VSCSI_NAMELEN];
 161         /* Returned by scsiback_make_tport() */
 162         struct se_wwn tport_wwn;
 163 };
 164
 165 struct scsiback_tpg {
 166         /* scsiback port target portal group tag for TCM */
 167         u16 tport_tpgt;
 168         /* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
 169         int tv_tpg_port_count;
 170         /* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
 171         int tv_tpg_fe_count;
 172         /* list for scsiback_list */
 173         struct list_head tv_tpg_list;
 174         /* Used to protect access for tpg_nexus */
 175         struct mutex tv_tpg_mutex;
 176         /* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
 177         struct scsiback_nexus *tpg_nexus;
 178         /* Pointer back to scsiback_tport */
 179         struct scsiback_tport *tport;
 180         /* Returned by scsiback_make_tpg() */
 181         struct se_portal_group se_tpg;
 182         /* alias used in xenstore */
 183         char param_alias[VSCSI_NAMELEN];
 184         /* list of info structures related to this target portal group */
 185         struct list_head info_list;
 186 };
 187
 188 #define SCSIBACK_INVALID_HANDLE (~0)
 189
 190 static bool log_print_stat;
 191 module_param(log_print_stat, bool, 0644);
 192
 193 static int scsiback_max_buffer_pages = 1024;
 194 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
 195 MODULE_PARM_DESC(max_buffer_pages,
 196 "Maximum number of free pages to keep in backend buffer");
 197
 198 static struct kmem_cache *scsiback_cachep;
 199 static DEFINE_SPINLOCK(free_pages_lock);
 200 static int free_pages_num;
 201 static LIST_HEAD(scsiback_free_pages);
 202
 203 /* Global spinlock to protect scsiback TPG list */
 204 static DEFINE_MUTEX(scsiback_mutex);
 205 static LIST_HEAD(scsiback_list);
 206
 207 static const struct target_core_fabric_ops scsiback_ops;
 208
 209 static void scsiback_get(struct vscsibk_info *info)
 210 {
 211         atomic_inc(&info->nr_unreplied_reqs);
 212 }
 213
 214 static void scsiback_put(struct vscsibk_info *info)
 215 {
 216         if (atomic_dec_and_test(&info->nr_unreplied_reqs))
 217                 wake_up(&info->waiting_to_free);
 218 }
 219
 220 static void put_free_pages(struct page **page, int num)
 221 {
 222         unsigned long flags;
 223         int i = free_pages_num + num, n = num;
 224
 225         if (num == 0)
 226                 return;
 227         if (i > scsiback_max_buffer_pages) {
 228                 n = min(num, i - scsiback_max_buffer_pages);
 229                 gnttab_free_pages(n, page + num - n);
 230                 n = num - n;
 231         }
 232         spin_lock_irqsave(&free_pages_lock, flags);
 233         for (i = 0; i < n; i++)
 234                 list_add(&page[i]->lru, &scsiback_free_pages);
 235         free_pages_num += n;
 236         spin_unlock_irqrestore(&free_pages_lock, flags);
 237 }
 238
 239 static int get_free_page(struct page **page)
 240 {
 241         unsigned long flags;
 242
 243         spin_lock_irqsave(&free_pages_lock, flags);
 244         if (list_empty(&scsiback_free_pages)) {
 245                 spin_unlock_irqrestore(&free_pages_lock, flags);
 246                 return gnttab_alloc_pages(1, page);
 247         }
 248         page[0] = list_first_entry(&scsiback_free_pages, struct page, lru);
 249         list_del(&page[0]->lru);
 250         free_pages_num--;
 251         spin_unlock_irqrestore(&free_pages_lock, flags);
 252         return 0;
 253 }
 254
 255 static unsigned long vaddr_page(struct page *page)
 256 {
 257         unsigned long pfn = page_to_pfn(page);
 258
 259         return (unsigned long)pfn_to_kaddr(pfn);
 260 }
 261
 262 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
 263 {
 264         return vaddr_page(req->pages[seg]);
 265 }
 266
 267 static void scsiback_print_status(char *sense_buffer, int errors,
 268                                         struct vscsibk_pend *pending_req)
 269 {
 270         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 271
 272         pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
 273                tpg->tport->tport_name, pending_req->v2p->lun,
 274                pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
 275                host_byte(errors), driver_byte(errors));
 276 }
 277
 278 static void scsiback_fast_flush_area(struct vscsibk_pend *req)
 279 {
 280         struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
 281         struct page *pages[VSCSI_GRANT_BATCH];
 282         unsigned int i, invcount = 0;
 283         grant_handle_t handle;
 284         int err;
 285
 286         kfree(req->sgl);
 287         req->sgl = NULL;
 288         req->n_sg = 0;
 289
 290         if (!req->n_grants)
 291                 return;
 292
 293         for (i = 0; i < req->n_grants; i++) {
 294                 handle = req->grant_handles[i];
 295                 if (handle == SCSIBACK_INVALID_HANDLE)
 296                         continue;
 297                 gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
 298                                     GNTMAP_host_map, handle);
 299                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 300                 pages[invcount] = req->pages[i];
 301                 put_page(pages[invcount]);
 302                 invcount++;
 303                 if (invcount < VSCSI_GRANT_BATCH)
 304                         continue;
 305                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 306                 BUG_ON(err);
 307                 invcount = 0;
 308         }
 309
 310         if (invcount) {
 311                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 312                 BUG_ON(err);
 313         }
 314
 315         put_free_pages(req->pages, req->n_grants);
 316         req->n_grants = 0;
 317 }
 318
 319 static void scsiback_free_translation_entry(struct kref *kref)
 320 {
 321         struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
 322         struct scsiback_tpg *tpg = entry->tpg;
 323
 324         mutex_lock(&tpg->tv_tpg_mutex);
 325         tpg->tv_tpg_fe_count--;
 326         mutex_unlock(&tpg->tv_tpg_mutex);
 327
 328         kfree(entry);
 329 }
 330
 331 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
 332                         uint32_t resid, struct vscsibk_pend *pending_req)
 333 {
 334         struct vscsiif_response *ring_res;
 335         struct vscsibk_info *info = pending_req->info;
 336         int notify;
 337         struct scsi_sense_hdr sshdr;
 338         unsigned long flags;
 339         unsigned len;
 340
 341         spin_lock_irqsave(&info->ring_lock, flags);
 342
 343         ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
 344         info->ring.rsp_prod_pvt++;
 345
 346         ring_res->rslt   = result;
 347         ring_res->rqid   = pending_req->rqid;
 348
 349         if (sense_buffer != NULL &&
 350             scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
 351                                  &sshdr)) {
 352                 len = min_t(unsigned, 8 + sense_buffer[7],
 353                             VSCSIIF_SENSE_BUFFERSIZE);
 354                 memcpy(ring_res->sense_buffer, sense_buffer, len);
 355                 ring_res->sense_len = len;
 356         } else {
 357                 ring_res->sense_len = 0;
 358         }
 359
 360         ring_res->residual_len = resid;
 361
 362         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
 363         spin_unlock_irqrestore(&info->ring_lock, flags);
 364
 365         if (notify)
 366                 notify_remote_via_irq(info->irq);
 367
 368         if (pending_req->v2p)
 369                 kref_put(&pending_req->v2p->kref,
 370                          scsiback_free_translation_entry);
 371 }
 372
 373 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
 374 {
 375         struct vscsibk_info *info = pending_req->info;
 376         unsigned char *sense_buffer;
 377         unsigned int resid;
 378         int errors;
 379
 380         sense_buffer = pending_req->sense_buffer;
 381         resid        = pending_req->se_cmd.residual_count;
 382         errors       = pending_req->result;
 383
 384         if (errors && log_print_stat)
 385                 scsiback_print_status(sense_buffer, errors, pending_req);
 386
 387         scsiback_fast_flush_area(pending_req);
 388         scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
 389         scsiback_put(info);
 390 }
 391
 392 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
 393 {
 394         struct se_cmd *se_cmd = &pending_req->se_cmd;
 395         struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
 396         int rc;
 397
 398         memset(pending_req->sense_buffer, 0, VSCSIIF_SENSE_BUFFERSIZE);
 399
 400         memset(se_cmd, 0, sizeof(*se_cmd));
 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, 0,
 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         int rc, err = FAILED;
 597         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 598         struct se_cmd *se_cmd = &pending_req->se_cmd;
 599         struct scsiback_tmr *tmr;
 600
 601         tmr = kzalloc(sizeof(struct scsiback_tmr), GFP_KERNEL);
 602         if (!tmr)
 603                 goto out;
 604
 605         init_waitqueue_head(&tmr->tmr_wait);
 606
 607         transport_init_se_cmd(se_cmd, tpg->se_tpg.se_tpg_tfo,
 608                 tpg->tpg_nexus->tvn_se_sess, 0, DMA_NONE, TCM_SIMPLE_TAG,
 609                 &pending_req->sense_buffer[0]);
 610
 611         rc = core_tmr_alloc_req(se_cmd, tmr, act, GFP_KERNEL);
 612         if (rc < 0)
 613                 goto out;
 614
 615         se_cmd->se_tmr_req->ref_task_tag = tag;
 616
 617         if (transport_lookup_tmr_lun(se_cmd, pending_req->v2p->lun) < 0)
 618                 goto out;
 619
 620         transport_generic_handle_tmr(se_cmd);
 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 out:
 627         if (tmr) {
 628                 transport_generic_free_cmd(&pending_req->se_cmd, 1);
 629                 kfree(tmr);
 630         }
 631
 632         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 633
 634         kmem_cache_free(scsiback_cachep, pending_req);
 635 }
 636
 637 /*
 638   Perform virtual to physical translation
 639 */
 640 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
 641                         struct ids_tuple *v)
 642 {
 643         struct v2p_entry *entry;
 644         struct list_head *head = &(info->v2p_entry_lists);
 645         unsigned long flags;
 646
 647         spin_lock_irqsave(&info->v2p_lock, flags);
 648         list_for_each_entry(entry, head, l) {
 649                 if ((entry->v.chn == v->chn) &&
 650                     (entry->v.tgt == v->tgt) &&
 651                     (entry->v.lun == v->lun)) {
 652                         kref_get(&entry->kref);
 653                         goto out;
 654                 }
 655         }
 656         entry = NULL;
 657
 658 out:
 659         spin_unlock_irqrestore(&info->v2p_lock, flags);
 660         return entry;
 661 }
 662
 663 static int prepare_pending_reqs(struct vscsibk_info *info,
 664                                 struct vscsiif_request *ring_req,
 665                                 struct vscsibk_pend *pending_req)
 666 {
 667         struct v2p_entry *v2p;
 668         struct ids_tuple vir;
 669
 670         pending_req->rqid       = ring_req->rqid;
 671         pending_req->info       = info;
 672
 673         vir.chn = ring_req->channel;
 674         vir.tgt = ring_req->id;
 675         vir.lun = ring_req->lun;
 676
 677         v2p = scsiback_do_translation(info, &vir);
 678         if (!v2p) {
 679                 pending_req->v2p = NULL;
 680                 pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
 681                         vir.chn, vir.tgt, vir.lun);
 682                 return -ENODEV;
 683         }
 684         pending_req->v2p = v2p;
 685
 686         /* request range check from frontend */
 687         pending_req->sc_data_direction = ring_req->sc_data_direction;
 688         if ((pending_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
 689                 (pending_req->sc_data_direction != DMA_TO_DEVICE) &&
 690                 (pending_req->sc_data_direction != DMA_FROM_DEVICE) &&
 691                 (pending_req->sc_data_direction != DMA_NONE)) {
 692                 pr_debug("invalid parameter data_dir = %d\n",
 693                         pending_req->sc_data_direction);
 694                 return -EINVAL;
 695         }
 696
 697         pending_req->cmd_len = ring_req->cmd_len;
 698         if (pending_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
 699                 pr_debug("invalid parameter cmd_len = %d\n",
 700                         pending_req->cmd_len);
 701                 return -EINVAL;
 702         }
 703         memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
 704
 705         return 0;
 706 }
 707
 708 static int scsiback_do_cmd_fn(struct vscsibk_info *info)
 709 {
 710         struct vscsiif_back_ring *ring = &info->ring;
 711         struct vscsiif_request ring_req;
 712         struct vscsibk_pend *pending_req;
 713         RING_IDX rc, rp;
 714         int err, more_to_do;
 715         uint32_t result;
 716
 717         rc = ring->req_cons;
 718         rp = ring->sring->req_prod;
 719         rmb();  /* guest system is accessing ring, too */
 720
 721         if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
 722                 rc = ring->rsp_prod_pvt;
 723                 pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 724                            info->domid, rp, rc, rp - rc);
 725                 info->ring_error = 1;
 726                 return 0;
 727         }
 728
 729         while ((rc != rp)) {
 730                 if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
 731                         break;
 732                 pending_req = kmem_cache_alloc(scsiback_cachep, GFP_KERNEL);
 733                 if (!pending_req)
 734                         return 1;
 735
 736                 ring_req = *RING_GET_REQUEST(ring, rc);
 737                 ring->req_cons = ++rc;
 738
 739                 err = prepare_pending_reqs(info, &ring_req, pending_req);
 740                 if (err) {
 741                         switch (err) {
 742                         case -ENODEV:
 743                                 result = DID_NO_CONNECT;
 744                                 break;
 745                         default:
 746                                 result = DRIVER_ERROR;
 747                                 break;
 748                         }
 749                         scsiback_do_resp_with_sense(NULL, result << 24, 0,
 750                                                     pending_req);
 751                         kmem_cache_free(scsiback_cachep, pending_req);
 752                         return 1;
 753                 }
 754
 755                 switch (ring_req.act) {
 756                 case VSCSIIF_ACT_SCSI_CDB:
 757                         if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
 758                                 scsiback_fast_flush_area(pending_req);
 759                                 scsiback_do_resp_with_sense(NULL,
 760                                         DRIVER_ERROR << 24, 0, pending_req);
 761                                 kmem_cache_free(scsiback_cachep, pending_req);
 762                         } else {
 763                                 scsiback_cmd_exec(pending_req);
 764                         }
 765                         break;
 766                 case VSCSIIF_ACT_SCSI_ABORT:
 767                         scsiback_device_action(pending_req, TMR_ABORT_TASK,
 768                                 ring_req.ref_rqid);
 769                         break;
 770                 case VSCSIIF_ACT_SCSI_RESET:
 771                         scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
 772                         break;
 773                 default:
 774                         pr_err_ratelimited("invalid request\n");
 775                         scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24,
 776                                                     0, pending_req);
 777                         kmem_cache_free(scsiback_cachep, pending_req);
 778                         break;
 779                 }
 780
 781                 /* Yield point for this unbounded loop. */
 782                 cond_resched();
 783         }
 784
 785         RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
 786         return more_to_do;
 787 }
 788
 789 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
 790 {
 791         struct vscsibk_info *info = dev_id;
 792
 793         if (info->ring_error)
 794                 return IRQ_HANDLED;
 795
 796         while (scsiback_do_cmd_fn(info))
 797                 cond_resched();
 798
 799         return IRQ_HANDLED;
 800 }
 801
 802 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 803                         evtchn_port_t evtchn)
 804 {
 805         void *area;
 806         struct vscsiif_sring *sring;
 807         int err;
 808
 809         if (info->irq)
 810                 return -1;
 811
 812         err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 813         if (err)
 814                 return err;
 815
 816         sring = (struct vscsiif_sring *)area;
 817         BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 818
 819         err = bind_interdomain_evtchn_to_irq(info->domid, evtchn);
 820         if (err < 0)
 821                 goto unmap_page;
 822
 823         info->irq = err;
 824
 825         err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
 826                                    IRQF_ONESHOT, "vscsiif-backend", info);
 827         if (err)
 828                 goto free_irq;
 829
 830         return 0;
 831
 832 free_irq:
 833         unbind_from_irqhandler(info->irq, info);
 834         info->irq = 0;
 835 unmap_page:
 836         xenbus_unmap_ring_vfree(info->dev, area);
 837
 838         return err;
 839 }
 840
 841 static int scsiback_map(struct vscsibk_info *info)
 842 {
 843         struct xenbus_device *dev = info->dev;
 844         unsigned int ring_ref, evtchn;
 845         int err;
 846
 847         err = xenbus_gather(XBT_NIL, dev->otherend,
 848                         "ring-ref", "%u", &ring_ref,
 849                         "event-channel", "%u", &evtchn, NULL);
 850         if (err) {
 851                 xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
 852                 return err;
 853         }
 854
 855         return scsiback_init_sring(info, ring_ref, evtchn);
 856 }
 857
 858 /*
 859   Add a new translation entry
 860 */
 861 static int scsiback_add_translation_entry(struct vscsibk_info *info,
 862                                           char *phy, struct ids_tuple *v)
 863 {
 864         int err = 0;
 865         struct v2p_entry *entry;
 866         struct v2p_entry *new;
 867         struct list_head *head = &(info->v2p_entry_lists);
 868         unsigned long flags;
 869         char *lunp;
 870         unsigned int lun;
 871         struct scsiback_tpg *tpg_entry, *tpg = NULL;
 872         char *error = "doesn't exist";
 873
 874         lunp = strrchr(phy, ':');
 875         if (!lunp) {
 876                 pr_err("illegal format of physical device %s\n", phy);
 877                 return -EINVAL;
 878         }
 879         *lunp = 0;
 880         lunp++;
 881         if (kstrtouint(lunp, 10, &lun) || lun >= TRANSPORT_MAX_LUNS_PER_TPG) {
 882                 pr_err("lun number not valid: %s\n", lunp);
 883                 return -EINVAL;
 884         }
 885
 886         mutex_lock(&scsiback_mutex);
 887         list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
 888                 if (!strcmp(phy, tpg_entry->tport->tport_name) ||
 889                     !strcmp(phy, tpg_entry->param_alias)) {
 890                         spin_lock(&tpg_entry->se_tpg.tpg_lun_lock);
 891                         if (tpg_entry->se_tpg.tpg_lun_list[lun]->lun_status ==
 892                             TRANSPORT_LUN_STATUS_ACTIVE) {
 893                                 if (!tpg_entry->tpg_nexus)
 894                                         error = "nexus undefined";
 895                                 else
 896                                         tpg = tpg_entry;
 897                         }
 898                         spin_unlock(&tpg_entry->se_tpg.tpg_lun_lock);
 899                         break;
 900                 }
 901         }
 902         if (tpg) {
 903                 mutex_lock(&tpg->tv_tpg_mutex);
 904                 tpg->tv_tpg_fe_count++;
 905                 mutex_unlock(&tpg->tv_tpg_mutex);
 906         }
 907         mutex_unlock(&scsiback_mutex);
 908
 909         if (!tpg) {
 910                 pr_err("%s:%d %s\n", phy, lun, error);
 911                 return -ENODEV;
 912         }
 913
 914         new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
 915         if (new == NULL) {
 916                 err = -ENOMEM;
 917                 goto out_free;
 918         }
 919
 920         spin_lock_irqsave(&info->v2p_lock, flags);
 921
 922         /* Check double assignment to identical virtual ID */
 923         list_for_each_entry(entry, head, l) {
 924                 if ((entry->v.chn == v->chn) &&
 925                     (entry->v.tgt == v->tgt) &&
 926                     (entry->v.lun == v->lun)) {
 927                         pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 928                         err = -EEXIST;
 929                         goto out;
 930                 }
 931
 932         }
 933
 934         /* Create a new translation entry and add to the list */
 935         kref_init(&new->kref);
 936         new->v = *v;
 937         new->tpg = tpg;
 938         new->lun = lun;
 939         list_add_tail(&new->l, head);
 940
 941 out:
 942         spin_unlock_irqrestore(&info->v2p_lock, flags);
 943
 944 out_free:
 945         mutex_lock(&tpg->tv_tpg_mutex);
 946         tpg->tv_tpg_fe_count--;
 947         mutex_unlock(&tpg->tv_tpg_mutex);
 948
 949         if (err)
 950                 kfree(new);
 951
 952         return err;
 953 }
 954
 955 static void __scsiback_del_translation_entry(struct v2p_entry *entry)
 956 {
 957         list_del(&entry->l);
 958         kref_put(&entry->kref, scsiback_free_translation_entry);
 959 }
 960
 961 /*
 962   Delete the translation entry specfied
 963 */
 964 static int scsiback_del_translation_entry(struct vscsibk_info *info,
 965                                           struct ids_tuple *v)
 966 {
 967         struct v2p_entry *entry;
 968         struct list_head *head = &(info->v2p_entry_lists);
 969         unsigned long flags;
 970
 971         spin_lock_irqsave(&info->v2p_lock, flags);
 972         /* Find out the translation entry specified */
 973         list_for_each_entry(entry, head, l) {
 974                 if ((entry->v.chn == v->chn) &&
 975                     (entry->v.tgt == v->tgt) &&
 976                     (entry->v.lun == v->lun)) {
 977                         goto found;
 978                 }
 979         }
 980
 981         spin_unlock_irqrestore(&info->v2p_lock, flags);
 982         return 1;
 983
 984 found:
 985         /* Delete the translation entry specfied */
 986         __scsiback_del_translation_entry(entry);
 987
 988         spin_unlock_irqrestore(&info->v2p_lock, flags);
 989         return 0;
 990 }
 991
 992 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
 993                                 char *phy, struct ids_tuple *vir, int try)
 994 {
 995         if (!scsiback_add_translation_entry(info, phy, vir)) {
 996                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
 997                                   "%d", XenbusStateInitialised)) {
 998                         pr_err("xenbus_printf error %s\n", state);
 999                         scsiback_del_translation_entry(info, vir);
1000                 }
1001         } else if (!try) {
1002                 xenbus_printf(XBT_NIL, info->dev->nodename, state,
1003                               "%d", XenbusStateClosed);
1004         }
1005 }
1006
1007 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1008                                 struct ids_tuple *vir)
1009 {
1010         if (!scsiback_del_translation_entry(info, vir)) {
1011                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1012                                   "%d", XenbusStateClosed))
1013                         pr_err("xenbus_printf error %s\n", state);
1014         }
1015 }
1016
1017 #define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1018 #define VSCSIBACK_OP_UPDATEDEV_STATE    2
1019
1020 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1021                                      char *ent)
1022 {
1023         int err;
1024         struct ids_tuple vir;
1025         char *val;
1026         int device_state;
1027         char phy[VSCSI_NAMELEN];
1028         char str[64];
1029         char state[64];
1030         struct xenbus_device *dev = info->dev;
1031
1032         /* read status */
1033         snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1034         err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1035         if (XENBUS_EXIST_ERR(err))
1036                 return;
1037
1038         /* physical SCSI device */
1039         snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1040         val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1041         if (IS_ERR(val)) {
1042                 xenbus_printf(XBT_NIL, dev->nodename, state,
1043                               "%d", XenbusStateClosed);
1044                 return;
1045         }
1046         strlcpy(phy, val, VSCSI_NAMELEN);
1047         kfree(val);
1048
1049         /* virtual SCSI device */
1050         snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1051         err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1052                            &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1053         if (XENBUS_EXIST_ERR(err)) {
1054                 xenbus_printf(XBT_NIL, dev->nodename, state,
1055                               "%d", XenbusStateClosed);
1056                 return;
1057         }
1058
1059         switch (op) {
1060         case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1061                 switch (device_state) {
1062                 case XenbusStateInitialising:
1063                         scsiback_do_add_lun(info, state, phy, &vir, 0);
1064                         break;
1065                 case XenbusStateConnected:
1066                         scsiback_do_add_lun(info, state, phy, &vir, 1);
1067                         break;
1068                 case XenbusStateClosing:
1069                         scsiback_do_del_lun(info, state, &vir);
1070                         break;
1071                 default:
1072                         break;
1073                 }
1074                 break;
1075
1076         case VSCSIBACK_OP_UPDATEDEV_STATE:
1077                 if (device_state == XenbusStateInitialised) {
1078                         /* modify vscsi-devs/dev-x/state */
1079                         if (xenbus_printf(XBT_NIL, dev->nodename, state,
1080                                           "%d", XenbusStateConnected)) {
1081                                 pr_err("xenbus_printf error %s\n", str);
1082                                 scsiback_del_translation_entry(info, &vir);
1083                                 xenbus_printf(XBT_NIL, dev->nodename, state,
1084                                               "%d", XenbusStateClosed);
1085                         }
1086                 }
1087                 break;
1088         /* When it is necessary, processing is added here. */
1089         default:
1090                 break;
1091         }
1092 }
1093
1094 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1095 {
1096         int i;
1097         char **dir;
1098         unsigned int ndir = 0;
1099
1100         dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1101                                &ndir);
1102         if (IS_ERR(dir))
1103                 return;
1104
1105         for (i = 0; i < ndir; i++)
1106                 scsiback_do_1lun_hotplug(info, op, dir[i]);
1107
1108         kfree(dir);
1109 }
1110
1111 static void scsiback_frontend_changed(struct xenbus_device *dev,
1112                                         enum xenbus_state frontend_state)
1113 {
1114         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1115
1116         switch (frontend_state) {
1117         case XenbusStateInitialising:
1118                 break;
1119
1120         case XenbusStateInitialised:
1121                 if (scsiback_map(info))
1122                         break;
1123
1124                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1125                 xenbus_switch_state(dev, XenbusStateConnected);
1126                 break;
1127
1128         case XenbusStateConnected:
1129                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1130
1131                 if (dev->state == XenbusStateConnected)
1132                         break;
1133
1134                 xenbus_switch_state(dev, XenbusStateConnected);
1135                 break;
1136
1137         case XenbusStateClosing:
1138                 if (info->irq)
1139                         scsiback_disconnect(info);
1140
1141                 xenbus_switch_state(dev, XenbusStateClosing);
1142                 break;
1143
1144         case XenbusStateClosed:
1145                 xenbus_switch_state(dev, XenbusStateClosed);
1146                 if (xenbus_dev_is_online(dev))
1147                         break;
1148                 /* fall through if not online */
1149         case XenbusStateUnknown:
1150                 device_unregister(&dev->dev);
1151                 break;
1152
1153         case XenbusStateReconfiguring:
1154                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1155                 xenbus_switch_state(dev, XenbusStateReconfigured);
1156
1157                 break;
1158
1159         default:
1160                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1161                                         frontend_state);
1162                 break;
1163         }
1164 }
1165
1166 /*
1167   Release the translation entry specfied
1168 */
1169 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1170 {
1171         struct v2p_entry *entry, *tmp;
1172         struct list_head *head = &(info->v2p_entry_lists);
1173         unsigned long flags;
1174
1175         spin_lock_irqsave(&info->v2p_lock, flags);
1176
1177         list_for_each_entry_safe(entry, tmp, head, l)
1178                 __scsiback_del_translation_entry(entry);
1179
1180         spin_unlock_irqrestore(&info->v2p_lock, flags);
1181 }
1182
1183 static int scsiback_remove(struct xenbus_device *dev)
1184 {
1185         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1186
1187         if (info->irq)
1188                 scsiback_disconnect(info);
1189
1190         scsiback_release_translation_entry(info);
1191
1192         dev_set_drvdata(&dev->dev, NULL);
1193
1194         return 0;
1195 }
1196
1197 static int scsiback_probe(struct xenbus_device *dev,
1198                            const struct xenbus_device_id *id)
1199 {
1200         int err;
1201
1202         struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1203                                             GFP_KERNEL);
1204
1205         pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1206
1207         if (!info) {
1208                 xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1209                 return -ENOMEM;
1210         }
1211         info->dev = dev;
1212         dev_set_drvdata(&dev->dev, info);
1213
1214         info->domid = dev->otherend_id;
1215         spin_lock_init(&info->ring_lock);
1216         info->ring_error = 0;
1217         atomic_set(&info->nr_unreplied_reqs, 0);
1218         init_waitqueue_head(&info->waiting_to_free);
1219         info->dev = dev;
1220         info->irq = 0;
1221         INIT_LIST_HEAD(&info->v2p_entry_lists);
1222         spin_lock_init(&info->v2p_lock);
1223
1224         err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1225                             SG_ALL);
1226         if (err)
1227                 xenbus_dev_error(dev, err, "writing feature-sg-grant");
1228
1229         err = xenbus_switch_state(dev, XenbusStateInitWait);
1230         if (err)
1231                 goto fail;
1232
1233         return 0;
1234
1235 fail:
1236         pr_warn("%s failed\n", __func__);
1237         scsiback_remove(dev);
1238
1239         return err;
1240 }
1241
1242 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1243 {
1244         switch (tport->tport_proto_id) {
1245         case SCSI_PROTOCOL_SAS:
1246                 return "SAS";
1247         case SCSI_PROTOCOL_FCP:
1248                 return "FCP";
1249         case SCSI_PROTOCOL_ISCSI:
1250                 return "iSCSI";
1251         default:
1252                 break;
1253         }
1254
1255         return "Unknown";
1256 }
1257
1258 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1259 {
1260         struct scsiback_tpg *tpg = container_of(se_tpg,
1261                                 struct scsiback_tpg, se_tpg);
1262         struct scsiback_tport *tport = tpg->tport;
1263
1264         return &tport->tport_name[0];
1265 }
1266
1267 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1268 {
1269         struct scsiback_tpg *tpg = container_of(se_tpg,
1270                                 struct scsiback_tpg, se_tpg);
1271         return tpg->tport_tpgt;
1272 }
1273
1274 static struct se_wwn *
1275 scsiback_make_tport(struct target_fabric_configfs *tf,
1276                      struct config_group *group,
1277                      const char *name)
1278 {
1279         struct scsiback_tport *tport;
1280         char *ptr;
1281         u64 wwpn = 0;
1282         int off = 0;
1283
1284         tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1285         if (!tport)
1286                 return ERR_PTR(-ENOMEM);
1287
1288         tport->tport_wwpn = wwpn;
1289         /*
1290          * Determine the emulated Protocol Identifier and Target Port Name
1291          * based on the incoming configfs directory name.
1292          */
1293         ptr = strstr(name, "naa.");
1294         if (ptr) {
1295                 tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1296                 goto check_len;
1297         }
1298         ptr = strstr(name, "fc.");
1299         if (ptr) {
1300                 tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1301                 off = 3; /* Skip over "fc." */
1302                 goto check_len;
1303         }
1304         ptr = strstr(name, "iqn.");
1305         if (ptr) {
1306                 tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1307                 goto check_len;
1308         }
1309
1310         pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1311         kfree(tport);
1312         return ERR_PTR(-EINVAL);
1313
1314 check_len:
1315         if (strlen(name) >= VSCSI_NAMELEN) {
1316                 pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1317                         scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1318                 kfree(tport);
1319                 return ERR_PTR(-EINVAL);
1320         }
1321         snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1322
1323         pr_debug("Allocated emulated Target %s Address: %s\n",
1324                  scsiback_dump_proto_id(tport), name);
1325
1326         return &tport->tport_wwn;
1327 }
1328
1329 static void scsiback_drop_tport(struct se_wwn *wwn)
1330 {
1331         struct scsiback_tport *tport = container_of(wwn,
1332                                 struct scsiback_tport, tport_wwn);
1333
1334         pr_debug("Deallocating emulated Target %s Address: %s\n",
1335                  scsiback_dump_proto_id(tport), tport->tport_name);
1336
1337         kfree(tport);
1338 }
1339
1340 static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1341 {
1342         return 1;
1343 }
1344
1345 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1346 {
1347         /*
1348          * Do not release struct se_cmd's containing a valid TMR pointer.
1349          * These will be released directly in scsiback_device_action()
1350          * with transport_generic_free_cmd().
1351          */
1352         if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
1353                 return 0;
1354
1355         transport_generic_free_cmd(se_cmd, 0);
1356         return 1;
1357 }
1358
1359 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1360 {
1361         struct vscsibk_pend *pending_req = container_of(se_cmd,
1362                                 struct vscsibk_pend, se_cmd);
1363
1364         kmem_cache_free(scsiback_cachep, pending_req);
1365 }
1366
1367 static int scsiback_shutdown_session(struct se_session *se_sess)
1368 {
1369         return 0;
1370 }
1371
1372 static void scsiback_close_session(struct se_session *se_sess)
1373 {
1374 }
1375
1376 static u32 scsiback_sess_get_index(struct se_session *se_sess)
1377 {
1378         return 0;
1379 }
1380
1381 static int scsiback_write_pending(struct se_cmd *se_cmd)
1382 {
1383         /* Go ahead and process the write immediately */
1384         target_execute_cmd(se_cmd);
1385
1386         return 0;
1387 }
1388
1389 static int scsiback_write_pending_status(struct se_cmd *se_cmd)
1390 {
1391         return 0;
1392 }
1393
1394 static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1395 {
1396 }
1397
1398 static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1399 {
1400         return 0;
1401 }
1402
1403 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1404 {
1405         struct vscsibk_pend *pending_req = container_of(se_cmd,
1406                                 struct vscsibk_pend, se_cmd);
1407
1408         pending_req->result = SAM_STAT_GOOD;
1409         scsiback_cmd_done(pending_req);
1410         return 0;
1411 }
1412
1413 static int scsiback_queue_status(struct se_cmd *se_cmd)
1414 {
1415         struct vscsibk_pend *pending_req = container_of(se_cmd,
1416                                 struct vscsibk_pend, se_cmd);
1417
1418         if (se_cmd->sense_buffer &&
1419             ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1420              (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1421                 pending_req->result = (DRIVER_SENSE << 24) |
1422                                       SAM_STAT_CHECK_CONDITION;
1423         else
1424                 pending_req->result = se_cmd->scsi_status;
1425
1426         scsiback_cmd_done(pending_req);
1427         return 0;
1428 }
1429
1430 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1431 {
1432         struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
1433         struct scsiback_tmr *tmr = se_tmr->fabric_tmr_ptr;
1434
1435         atomic_set(&tmr->tmr_complete, 1);
1436         wake_up(&tmr->tmr_wait);
1437 }
1438
1439 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1440 {
1441 }
1442
1443 static ssize_t scsiback_tpg_param_show_alias(struct se_portal_group *se_tpg,
1444                                              char *page)
1445 {
1446         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1447                                                 se_tpg);
1448         ssize_t rb;
1449
1450         mutex_lock(&tpg->tv_tpg_mutex);
1451         rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1452         mutex_unlock(&tpg->tv_tpg_mutex);
1453
1454         return rb;
1455 }
1456
1457 static ssize_t scsiback_tpg_param_store_alias(struct se_portal_group *se_tpg,
1458                                               const char *page, size_t count)
1459 {
1460         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1461                                                 se_tpg);
1462         int len;
1463
1464         if (strlen(page) >= VSCSI_NAMELEN) {
1465                 pr_err("param alias: %s, exceeds max: %d\n", page,
1466                         VSCSI_NAMELEN);
1467                 return -EINVAL;
1468         }
1469
1470         mutex_lock(&tpg->tv_tpg_mutex);
1471         len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1472         if (tpg->param_alias[len - 1] == '\n')
1473                 tpg->param_alias[len - 1] = '\0';
1474         mutex_unlock(&tpg->tv_tpg_mutex);
1475
1476         return count;
1477 }
1478
1479 TF_TPG_PARAM_ATTR(scsiback, alias, S_IRUGO | S_IWUSR);
1480
1481 static struct configfs_attribute *scsiback_param_attrs[] = {
1482         &scsiback_tpg_param_alias.attr,
1483         NULL,
1484 };
1485
1486 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1487                                 const char *name)
1488 {
1489         struct se_portal_group *se_tpg;
1490         struct se_session *se_sess;
1491         struct scsiback_nexus *tv_nexus;
1492
1493         mutex_lock(&tpg->tv_tpg_mutex);
1494         if (tpg->tpg_nexus) {
1495                 mutex_unlock(&tpg->tv_tpg_mutex);
1496                 pr_debug("tpg->tpg_nexus already exists\n");
1497                 return -EEXIST;
1498         }
1499         se_tpg = &tpg->se_tpg;
1500
1501         tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1502         if (!tv_nexus) {
1503                 mutex_unlock(&tpg->tv_tpg_mutex);
1504                 return -ENOMEM;
1505         }
1506         /*
1507          * Initialize the struct se_session pointer
1508          */
1509         tv_nexus->tvn_se_sess = transport_init_session(TARGET_PROT_NORMAL);
1510         if (IS_ERR(tv_nexus->tvn_se_sess)) {
1511                 mutex_unlock(&tpg->tv_tpg_mutex);
1512                 kfree(tv_nexus);
1513                 return -ENOMEM;
1514         }
1515         se_sess = tv_nexus->tvn_se_sess;
1516         /*
1517          * Since we are running in 'demo mode' this call with generate a
1518          * struct se_node_acl for the scsiback struct se_portal_group with
1519          * the SCSI Initiator port name of the passed configfs group 'name'.
1520          */
1521         tv_nexus->tvn_se_sess->se_node_acl = core_tpg_check_initiator_node_acl(
1522                                 se_tpg, (unsigned char *)name);
1523         if (!tv_nexus->tvn_se_sess->se_node_acl) {
1524                 mutex_unlock(&tpg->tv_tpg_mutex);
1525                 pr_debug("core_tpg_check_initiator_node_acl() failed for %s\n",
1526                          name);
1527                 goto out;
1528         }
1529         /* Now register the TCM pvscsi virtual I_T Nexus as active. */
1530         transport_register_session(se_tpg, tv_nexus->tvn_se_sess->se_node_acl,
1531                         tv_nexus->tvn_se_sess, tv_nexus);
1532         tpg->tpg_nexus = tv_nexus;
1533
1534         mutex_unlock(&tpg->tv_tpg_mutex);
1535         return 0;
1536
1537 out:
1538         transport_free_session(se_sess);
1539         kfree(tv_nexus);
1540         return -ENOMEM;
1541 }
1542
1543 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1544 {
1545         struct se_session *se_sess;
1546         struct scsiback_nexus *tv_nexus;
1547
1548         mutex_lock(&tpg->tv_tpg_mutex);
1549         tv_nexus = tpg->tpg_nexus;
1550         if (!tv_nexus) {
1551                 mutex_unlock(&tpg->tv_tpg_mutex);
1552                 return -ENODEV;
1553         }
1554
1555         se_sess = tv_nexus->tvn_se_sess;
1556         if (!se_sess) {
1557                 mutex_unlock(&tpg->tv_tpg_mutex);
1558                 return -ENODEV;
1559         }
1560
1561         if (tpg->tv_tpg_port_count != 0) {
1562                 mutex_unlock(&tpg->tv_tpg_mutex);
1563                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1564                         tpg->tv_tpg_port_count);
1565                 return -EBUSY;
1566         }
1567
1568         if (tpg->tv_tpg_fe_count != 0) {
1569                 mutex_unlock(&tpg->tv_tpg_mutex);
1570                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1571                         tpg->tv_tpg_fe_count);
1572                 return -EBUSY;
1573         }
1574
1575         pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1576                 scsiback_dump_proto_id(tpg->tport),
1577                 tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1578
1579         /*
1580          * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1581          */
1582         transport_deregister_session(tv_nexus->tvn_se_sess);
1583         tpg->tpg_nexus = NULL;
1584         mutex_unlock(&tpg->tv_tpg_mutex);
1585
1586         kfree(tv_nexus);
1587         return 0;
1588 }
1589
1590 static ssize_t scsiback_tpg_show_nexus(struct se_portal_group *se_tpg,
1591                                         char *page)
1592 {
1593         struct scsiback_tpg *tpg = container_of(se_tpg,
1594                                 struct scsiback_tpg, se_tpg);
1595         struct scsiback_nexus *tv_nexus;
1596         ssize_t ret;
1597
1598         mutex_lock(&tpg->tv_tpg_mutex);
1599         tv_nexus = tpg->tpg_nexus;
1600         if (!tv_nexus) {
1601                 mutex_unlock(&tpg->tv_tpg_mutex);
1602                 return -ENODEV;
1603         }
1604         ret = snprintf(page, PAGE_SIZE, "%s\n",
1605                         tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1606         mutex_unlock(&tpg->tv_tpg_mutex);
1607
1608         return ret;
1609 }
1610
1611 static ssize_t scsiback_tpg_store_nexus(struct se_portal_group *se_tpg,
1612                                          const char *page,
1613                                          size_t count)
1614 {
1615         struct scsiback_tpg *tpg = container_of(se_tpg,
1616                                 struct scsiback_tpg, se_tpg);
1617         struct scsiback_tport *tport_wwn = tpg->tport;
1618         unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1619         int ret;
1620         /*
1621          * Shutdown the active I_T nexus if 'NULL' is passed.
1622          */
1623         if (!strncmp(page, "NULL", 4)) {
1624                 ret = scsiback_drop_nexus(tpg);
1625                 return (!ret) ? count : ret;
1626         }
1627         /*
1628          * Otherwise make sure the passed virtual Initiator port WWN matches
1629          * the fabric protocol_id set in scsiback_make_tport(), and call
1630          * scsiback_make_nexus().
1631          */
1632         if (strlen(page) >= VSCSI_NAMELEN) {
1633                 pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1634                         page, VSCSI_NAMELEN);
1635                 return -EINVAL;
1636         }
1637         snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1638
1639         ptr = strstr(i_port, "naa.");
1640         if (ptr) {
1641                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1642                         pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1643                                 i_port, scsiback_dump_proto_id(tport_wwn));
1644                         return -EINVAL;
1645                 }
1646                 port_ptr = &i_port[0];
1647                 goto check_newline;
1648         }
1649         ptr = strstr(i_port, "fc.");
1650         if (ptr) {
1651                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1652                         pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1653                                 i_port, scsiback_dump_proto_id(tport_wwn));
1654                         return -EINVAL;
1655                 }
1656                 port_ptr = &i_port[3]; /* Skip over "fc." */
1657                 goto check_newline;
1658         }
1659         ptr = strstr(i_port, "iqn.");
1660         if (ptr) {
1661                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1662                         pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1663                                 i_port, scsiback_dump_proto_id(tport_wwn));
1664                         return -EINVAL;
1665                 }
1666                 port_ptr = &i_port[0];
1667                 goto check_newline;
1668         }
1669         pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1670                 i_port);
1671         return -EINVAL;
1672         /*
1673          * Clear any trailing newline for the NAA WWN
1674          */
1675 check_newline:
1676         if (i_port[strlen(i_port) - 1] == '\n')
1677                 i_port[strlen(i_port) - 1] = '\0';
1678
1679         ret = scsiback_make_nexus(tpg, port_ptr);
1680         if (ret < 0)
1681                 return ret;
1682
1683         return count;
1684 }
1685
1686 TF_TPG_BASE_ATTR(scsiback, nexus, S_IRUGO | S_IWUSR);
1687
1688 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1689         &scsiback_tpg_nexus.attr,
1690         NULL,
1691 };
1692
1693 static ssize_t
1694 scsiback_wwn_show_attr_version(struct target_fabric_configfs *tf,
1695                                 char *page)
1696 {
1697         return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1698                 UTS_RELEASE"\n",
1699                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1700 }
1701
1702 TF_WWN_ATTR_RO(scsiback, version);
1703
1704 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1705         &scsiback_wwn_version.attr,
1706         NULL,
1707 };
1708
1709 static char *scsiback_get_fabric_name(void)
1710 {
1711         return "xen-pvscsi";
1712 }
1713
1714 static int scsiback_port_link(struct se_portal_group *se_tpg,
1715                                struct se_lun *lun)
1716 {
1717         struct scsiback_tpg *tpg = container_of(se_tpg,
1718                                 struct scsiback_tpg, se_tpg);
1719
1720         mutex_lock(&tpg->tv_tpg_mutex);
1721         tpg->tv_tpg_port_count++;
1722         mutex_unlock(&tpg->tv_tpg_mutex);
1723
1724         return 0;
1725 }
1726
1727 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1728                                   struct se_lun *lun)
1729 {
1730         struct scsiback_tpg *tpg = container_of(se_tpg,
1731                                 struct scsiback_tpg, se_tpg);
1732
1733         mutex_lock(&tpg->tv_tpg_mutex);
1734         tpg->tv_tpg_port_count--;
1735         mutex_unlock(&tpg->tv_tpg_mutex);
1736 }
1737
1738 static struct se_portal_group *
1739 scsiback_make_tpg(struct se_wwn *wwn,
1740                    struct config_group *group,
1741                    const char *name)
1742 {
1743         struct scsiback_tport *tport = container_of(wwn,
1744                         struct scsiback_tport, tport_wwn);
1745
1746         struct scsiback_tpg *tpg;
1747         u16 tpgt;
1748         int ret;
1749
1750         if (strstr(name, "tpgt_") != name)
1751                 return ERR_PTR(-EINVAL);
1752         ret = kstrtou16(name + 5, 10, &tpgt);
1753         if (ret)
1754                 return ERR_PTR(ret);
1755
1756         tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1757         if (!tpg)
1758                 return ERR_PTR(-ENOMEM);
1759
1760         mutex_init(&tpg->tv_tpg_mutex);
1761         INIT_LIST_HEAD(&tpg->tv_tpg_list);
1762         INIT_LIST_HEAD(&tpg->info_list);
1763         tpg->tport = tport;
1764         tpg->tport_tpgt = tpgt;
1765
1766         ret = core_tpg_register(&scsiback_ops, wwn, &tpg->se_tpg,
1767                                 tport->tport_proto_id);
1768         if (ret < 0) {
1769                 kfree(tpg);
1770                 return NULL;
1771         }
1772         mutex_lock(&scsiback_mutex);
1773         list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1774         mutex_unlock(&scsiback_mutex);
1775
1776         return &tpg->se_tpg;
1777 }
1778
1779 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1780 {
1781         struct scsiback_tpg *tpg = container_of(se_tpg,
1782                                 struct scsiback_tpg, se_tpg);
1783
1784         mutex_lock(&scsiback_mutex);
1785         list_del(&tpg->tv_tpg_list);
1786         mutex_unlock(&scsiback_mutex);
1787         /*
1788          * Release the virtual I_T Nexus for this xen-pvscsi TPG
1789          */
1790         scsiback_drop_nexus(tpg);
1791         /*
1792          * Deregister the se_tpg from TCM.
1793          */
1794         core_tpg_deregister(se_tpg);
1795         kfree(tpg);
1796 }
1797
1798 static int scsiback_check_true(struct se_portal_group *se_tpg)
1799 {
1800         return 1;
1801 }
1802
1803 static int scsiback_check_false(struct se_portal_group *se_tpg)
1804 {
1805         return 0;
1806 }
1807
1808 static const struct target_core_fabric_ops scsiback_ops = {
1809         .module                         = THIS_MODULE,
1810         .name                           = "xen-pvscsi",
1811         .get_fabric_name                = scsiback_get_fabric_name,
1812         .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1813         .tpg_get_tag                    = scsiback_get_tag,
1814         .tpg_check_demo_mode            = scsiback_check_true,
1815         .tpg_check_demo_mode_cache      = scsiback_check_true,
1816         .tpg_check_demo_mode_write_protect = scsiback_check_false,
1817         .tpg_check_prod_mode_write_protect = scsiback_check_false,
1818         .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1819         .check_stop_free                = scsiback_check_stop_free,
1820         .release_cmd                    = scsiback_release_cmd,
1821         .put_session                    = NULL,
1822         .shutdown_session               = scsiback_shutdown_session,
1823         .close_session                  = scsiback_close_session,
1824         .sess_get_index                 = scsiback_sess_get_index,
1825         .sess_get_initiator_sid         = NULL,
1826         .write_pending                  = scsiback_write_pending,
1827         .write_pending_status           = scsiback_write_pending_status,
1828         .set_default_node_attributes    = scsiback_set_default_node_attrs,
1829         .get_cmd_state                  = scsiback_get_cmd_state,
1830         .queue_data_in                  = scsiback_queue_data_in,
1831         .queue_status                   = scsiback_queue_status,
1832         .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1833         .aborted_task                   = scsiback_aborted_task,
1834         /*
1835          * Setup callers for generic logic in target_core_fabric_configfs.c
1836          */
1837         .fabric_make_wwn                = scsiback_make_tport,
1838         .fabric_drop_wwn                = scsiback_drop_tport,
1839         .fabric_make_tpg                = scsiback_make_tpg,
1840         .fabric_drop_tpg                = scsiback_drop_tpg,
1841         .fabric_post_link               = scsiback_port_link,
1842         .fabric_pre_unlink              = scsiback_port_unlink,
1843
1844         .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1845         .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1846         .tfc_tpg_param_attrs            = scsiback_param_attrs,
1847 };
1848
1849 static const struct xenbus_device_id scsiback_ids[] = {
1850         { "vscsi" },
1851         { "" }
1852 };
1853
1854 static struct xenbus_driver scsiback_driver = {
1855         .ids                    = scsiback_ids,
1856         .probe                  = scsiback_probe,
1857         .remove                 = scsiback_remove,
1858         .otherend_changed       = scsiback_frontend_changed
1859 };
1860
1861 static void scsiback_init_pend(void *p)
1862 {
1863         struct vscsibk_pend *pend = p;
1864         int i;
1865
1866         memset(pend, 0, sizeof(*pend));
1867         for (i = 0; i < VSCSI_MAX_GRANTS; i++)
1868                 pend->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
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         scsiback_cachep = kmem_cache_create("vscsiif_cache",
1882                 sizeof(struct vscsibk_pend), 0, 0, scsiback_init_pend);
1883         if (!scsiback_cachep)
1884                 return -ENOMEM;
1885
1886         ret = xenbus_register_backend(&scsiback_driver);
1887         if (ret)
1888                 goto out_cache_destroy;
1889
1890         ret = target_register_template(&scsiback_ops);
1891         if (ret)
1892                 goto out_unregister_xenbus;
1893
1894         return 0;
1895
1896 out_unregister_xenbus:
1897         xenbus_unregister_driver(&scsiback_driver);
1898 out_cache_destroy:
1899         kmem_cache_destroy(scsiback_cachep);
1900         pr_err("%s: error %d\n", __func__, ret);
1901         return ret;
1902 }
1903
1904 static void __exit scsiback_exit(void)
1905 {
1906         struct page *page;
1907
1908         while (free_pages_num) {
1909                 if (get_free_page(&page))
1910                         BUG();
1911                 gnttab_free_pages(1, &page);
1912         }
1913         target_unregister_template(&scsiback_ops);
1914         xenbus_unregister_driver(&scsiback_driver);
1915         kmem_cache_destroy(scsiback_cachep);
1916 }
1917
1918 module_init(scsiback_init);
1919 module_exit(scsiback_exit);
1920
1921 MODULE_DESCRIPTION("Xen SCSI backend driver");
1922 MODULE_LICENSE("Dual BSD/GPL");
1923 MODULE_ALIAS("xen-backend:vscsi");
1924 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");