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
  95         spinlock_t ring_lock;
  96         atomic_t nr_unreplied_reqs;
  97
  98         spinlock_t v2p_lock;
  99         struct list_head v2p_entry_lists;
 100
 101         wait_queue_head_t waiting_to_free;
 102 };
 103
 104 /* theoretical maximum of grants for one request */
 105 #define VSCSI_MAX_GRANTS        (SG_ALL + VSCSIIF_SG_TABLESIZE)
 106
 107 /*
 108  * VSCSI_GRANT_BATCH is the maximum number of grants to be processed in one
 109  * call to map/unmap grants. Don't choose it too large, as there are arrays
 110  * with VSCSI_GRANT_BATCH elements allocated on the stack.
 111  */
 112 #define VSCSI_GRANT_BATCH       16
 113
 114 struct vscsibk_pend {
 115         uint16_t rqid;
 116
 117         uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE];
 118         uint8_t cmd_len;
 119
 120         uint8_t sc_data_direction;
 121         uint16_t n_sg;          /* real length of SG list */
 122         uint16_t n_grants;      /* SG pages and potentially SG list */
 123         uint32_t data_len;
 124         uint32_t result;
 125
 126         struct vscsibk_info *info;
 127         struct v2p_entry *v2p;
 128         struct scatterlist *sgl;
 129
 130         uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];
 131
 132         grant_handle_t grant_handles[VSCSI_MAX_GRANTS];
 133         struct page *pages[VSCSI_MAX_GRANTS];
 134
 135         struct se_cmd se_cmd;
 136
 137         struct completion tmr_done;
 138 };
 139
 140 #define VSCSI_DEFAULT_SESSION_TAGS      128
 141
 142 struct scsiback_nexus {
 143         /* Pointer to TCM session for I_T Nexus */
 144         struct se_session *tvn_se_sess;
 145 };
 146
 147 struct scsiback_tport {
 148         /* SCSI protocol the tport is providing */
 149         u8 tport_proto_id;
 150         /* Binary World Wide unique Port Name for pvscsi Target port */
 151         u64 tport_wwpn;
 152         /* ASCII formatted WWPN for pvscsi Target port */
 153         char tport_name[VSCSI_NAMELEN];
 154         /* Returned by scsiback_make_tport() */
 155         struct se_wwn tport_wwn;
 156 };
 157
 158 struct scsiback_tpg {
 159         /* scsiback port target portal group tag for TCM */
 160         u16 tport_tpgt;
 161         /* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
 162         int tv_tpg_port_count;
 163         /* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
 164         int tv_tpg_fe_count;
 165         /* list for scsiback_list */
 166         struct list_head tv_tpg_list;
 167         /* Used to protect access for tpg_nexus */
 168         struct mutex tv_tpg_mutex;
 169         /* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
 170         struct scsiback_nexus *tpg_nexus;
 171         /* Pointer back to scsiback_tport */
 172         struct scsiback_tport *tport;
 173         /* Returned by scsiback_make_tpg() */
 174         struct se_portal_group se_tpg;
 175         /* alias used in xenstore */
 176         char param_alias[VSCSI_NAMELEN];
 177         /* list of info structures related to this target portal group */
 178         struct list_head info_list;
 179 };
 180
 181 #define SCSIBACK_INVALID_HANDLE (~0)
 182
 183 static bool log_print_stat;
 184 module_param(log_print_stat, bool, 0644);
 185
 186 static int scsiback_max_buffer_pages = 1024;
 187 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
 188 MODULE_PARM_DESC(max_buffer_pages,
 189 "Maximum number of free pages to keep in backend buffer");
 190
 191 static DEFINE_SPINLOCK(free_pages_lock);
 192 static int free_pages_num;
 193 static LIST_HEAD(scsiback_free_pages);
 194
 195 /* Global spinlock to protect scsiback TPG list */
 196 static DEFINE_MUTEX(scsiback_mutex);
 197 static LIST_HEAD(scsiback_list);
 198
 199 static void scsiback_get(struct vscsibk_info *info)
 200 {
 201         atomic_inc(&info->nr_unreplied_reqs);
 202 }
 203
 204 static void scsiback_put(struct vscsibk_info *info)
 205 {
 206         if (atomic_dec_and_test(&info->nr_unreplied_reqs))
 207                 wake_up(&info->waiting_to_free);
 208 }
 209
 210 static void put_free_pages(struct page **page, int num)
 211 {
 212         unsigned long flags;
 213         int i = free_pages_num + num, n = num;
 214
 215         if (num == 0)
 216                 return;
 217         if (i > scsiback_max_buffer_pages) {
 218                 n = min(num, i - scsiback_max_buffer_pages);
 219                 gnttab_free_pages(n, page + num - n);
 220                 n = num - n;
 221         }
 222         spin_lock_irqsave(&free_pages_lock, flags);
 223         for (i = 0; i < n; i++)
 224                 list_add(&page[i]->lru, &scsiback_free_pages);
 225         free_pages_num += n;
 226         spin_unlock_irqrestore(&free_pages_lock, flags);
 227 }
 228
 229 static int get_free_page(struct page **page)
 230 {
 231         unsigned long flags;
 232
 233         spin_lock_irqsave(&free_pages_lock, flags);
 234         if (list_empty(&scsiback_free_pages)) {
 235                 spin_unlock_irqrestore(&free_pages_lock, flags);
 236                 return gnttab_alloc_pages(1, page);
 237         }
 238         page[0] = list_first_entry(&scsiback_free_pages, struct page, lru);
 239         list_del(&page[0]->lru);
 240         free_pages_num--;
 241         spin_unlock_irqrestore(&free_pages_lock, flags);
 242         return 0;
 243 }
 244
 245 static unsigned long vaddr_page(struct page *page)
 246 {
 247         unsigned long pfn = page_to_pfn(page);
 248
 249         return (unsigned long)pfn_to_kaddr(pfn);
 250 }
 251
 252 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
 253 {
 254         return vaddr_page(req->pages[seg]);
 255 }
 256
 257 static void scsiback_print_status(char *sense_buffer, int errors,
 258                                         struct vscsibk_pend *pending_req)
 259 {
 260         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 261
 262         pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
 263                tpg->tport->tport_name, pending_req->v2p->lun,
 264                pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
 265                host_byte(errors), driver_byte(errors));
 266 }
 267
 268 static void scsiback_fast_flush_area(struct vscsibk_pend *req)
 269 {
 270         struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
 271         struct page *pages[VSCSI_GRANT_BATCH];
 272         unsigned int i, invcount = 0;
 273         grant_handle_t handle;
 274         int err;
 275
 276         kfree(req->sgl);
 277         req->sgl = NULL;
 278         req->n_sg = 0;
 279
 280         if (!req->n_grants)
 281                 return;
 282
 283         for (i = 0; i < req->n_grants; i++) {
 284                 handle = req->grant_handles[i];
 285                 if (handle == SCSIBACK_INVALID_HANDLE)
 286                         continue;
 287                 gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
 288                                     GNTMAP_host_map, handle);
 289                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 290                 pages[invcount] = req->pages[i];
 291                 put_page(pages[invcount]);
 292                 invcount++;
 293                 if (invcount < VSCSI_GRANT_BATCH)
 294                         continue;
 295                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 296                 BUG_ON(err);
 297                 invcount = 0;
 298         }
 299
 300         if (invcount) {
 301                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 302                 BUG_ON(err);
 303         }
 304
 305         put_free_pages(req->pages, req->n_grants);
 306         req->n_grants = 0;
 307 }
 308
 309 static void scsiback_free_translation_entry(struct kref *kref)
 310 {
 311         struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
 312         struct scsiback_tpg *tpg = entry->tpg;
 313
 314         mutex_lock(&tpg->tv_tpg_mutex);
 315         tpg->tv_tpg_fe_count--;
 316         mutex_unlock(&tpg->tv_tpg_mutex);
 317
 318         kfree(entry);
 319 }
 320
 321 static void scsiback_send_response(struct vscsibk_info *info,
 322                         char *sense_buffer, int32_t result, uint32_t resid,
 323                         uint16_t rqid)
 324 {
 325         struct vscsiif_response *ring_res;
 326         int notify;
 327         struct scsi_sense_hdr sshdr;
 328         unsigned long flags;
 329         unsigned len;
 330
 331         spin_lock_irqsave(&info->ring_lock, flags);
 332
 333         ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
 334         info->ring.rsp_prod_pvt++;
 335
 336         ring_res->rslt   = result;
 337         ring_res->rqid   = rqid;
 338
 339         if (sense_buffer != NULL &&
 340             scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
 341                                  &sshdr)) {
 342                 len = min_t(unsigned, 8 + sense_buffer[7],
 343                             VSCSIIF_SENSE_BUFFERSIZE);
 344                 memcpy(ring_res->sense_buffer, sense_buffer, len);
 345                 ring_res->sense_len = len;
 346         } else {
 347                 ring_res->sense_len = 0;
 348         }
 349
 350         ring_res->residual_len = resid;
 351
 352         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
 353         spin_unlock_irqrestore(&info->ring_lock, flags);
 354
 355         if (notify)
 356                 notify_remote_via_irq(info->irq);
 357 }
 358
 359 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
 360                         uint32_t resid, struct vscsibk_pend *pending_req)
 361 {
 362         scsiback_send_response(pending_req->info, sense_buffer, result,
 363                                resid, pending_req->rqid);
 364
 365         if (pending_req->v2p)
 366                 kref_put(&pending_req->v2p->kref,
 367                          scsiback_free_translation_entry);
 368 }
 369
 370 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
 371 {
 372         struct vscsibk_info *info = pending_req->info;
 373         unsigned char *sense_buffer;
 374         unsigned int resid;
 375         int errors;
 376
 377         sense_buffer = pending_req->sense_buffer;
 378         resid        = pending_req->se_cmd.residual_count;
 379         errors       = pending_req->result;
 380
 381         if (errors && log_print_stat)
 382                 scsiback_print_status(sense_buffer, errors, pending_req);
 383
 384         scsiback_fast_flush_area(pending_req);
 385         scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
 386         scsiback_put(info);
 387         /*
 388          * Drop the extra KREF_ACK reference taken by target_submit_cmd_map_sgls()
 389          * ahead of scsiback_check_stop_free() ->  transport_generic_free_cmd()
 390          * final se_cmd->cmd_kref put.
 391          */
 392         target_put_sess_cmd(&pending_req->se_cmd);
 393 }
 394
 395 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
 396 {
 397         struct se_cmd *se_cmd = &pending_req->se_cmd;
 398         struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
 399         int rc;
 400
 401         scsiback_get(pending_req->info);
 402         se_cmd->tag = pending_req->rqid;
 403         rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,
 404                         pending_req->sense_buffer, pending_req->v2p->lun,
 405                         pending_req->data_len, 0,
 406                         pending_req->sc_data_direction, TARGET_SCF_ACK_KREF,
 407                         pending_req->sgl, pending_req->n_sg,
 408                         NULL, 0, NULL, 0);
 409         if (rc < 0) {
 410                 transport_send_check_condition_and_sense(se_cmd,
 411                                 TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
 412                 transport_generic_free_cmd(se_cmd, 0);
 413         }
 414 }
 415
 416 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 417         struct page **pg, grant_handle_t *grant, int cnt)
 418 {
 419         int err, i;
 420
 421         if (!cnt)
 422                 return 0;
 423
 424         err = gnttab_map_refs(map, NULL, pg, cnt);
 425         for (i = 0; i < cnt; i++) {
 426                 if (unlikely(map[i].status != GNTST_okay)) {
 427                         pr_err("invalid buffer -- could not remap it\n");
 428                         map[i].handle = SCSIBACK_INVALID_HANDLE;
 429                         if (!err)
 430                                 err = -ENOMEM;
 431                 } else {
 432                         get_page(pg[i]);
 433                 }
 434                 grant[i] = map[i].handle;
 435         }
 436         return err;
 437 }
 438
 439 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
 440                         struct scsiif_request_segment *seg, struct page **pg,
 441                         grant_handle_t *grant, int cnt, u32 flags)
 442 {
 443         int mapcount = 0, i, err = 0;
 444         struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
 445         struct vscsibk_info *info = pending_req->info;
 446
 447         for (i = 0; i < cnt; i++) {
 448                 if (get_free_page(pg + mapcount)) {
 449                         put_free_pages(pg, mapcount);
 450                         pr_err("no grant page\n");
 451                         return -ENOMEM;
 452                 }
 453                 gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
 454                                   flags, seg[i].gref, info->domid);
 455                 mapcount++;
 456                 if (mapcount < VSCSI_GRANT_BATCH)
 457                         continue;
 458                 err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 459                 pg += mapcount;
 460                 grant += mapcount;
 461                 pending_req->n_grants += mapcount;
 462                 if (err)
 463                         return err;
 464                 mapcount = 0;
 465         }
 466         err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 467         pending_req->n_grants += mapcount;
 468         return err;
 469 }
 470
 471 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 472                                         struct vscsibk_pend *pending_req)
 473 {
 474         u32 flags;
 475         int i, err, n_segs, i_seg = 0;
 476         struct page **pg;
 477         struct scsiif_request_segment *seg;
 478         unsigned long end_seg = 0;
 479         unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
 480         unsigned int nr_sgl = 0;
 481         struct scatterlist *sg;
 482         grant_handle_t *grant;
 483
 484         pending_req->n_sg = 0;
 485         pending_req->n_grants = 0;
 486         pending_req->data_len = 0;
 487
 488         nr_segments &= ~VSCSIIF_SG_GRANT;
 489         if (!nr_segments)
 490                 return 0;
 491
 492         if (nr_segments > VSCSIIF_SG_TABLESIZE) {
 493                 pr_debug("invalid parameter nr_seg = %d\n",
 494                         ring_req->nr_segments);
 495                 return -EINVAL;
 496         }
 497
 498         if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
 499                 err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
 500                         pending_req->pages, pending_req->grant_handles,
 501                         nr_segments, GNTMAP_host_map | GNTMAP_readonly);
 502                 if (err)
 503                         return err;
 504                 nr_sgl = nr_segments;
 505                 nr_segments = 0;
 506                 for (i = 0; i < nr_sgl; i++) {
 507                         n_segs = ring_req->seg[i].length /
 508                                  sizeof(struct scsiif_request_segment);
 509                         if ((unsigned)ring_req->seg[i].offset +
 510                             (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
 511                             n_segs * sizeof(struct scsiif_request_segment) !=
 512                             ring_req->seg[i].length)
 513                                 return -EINVAL;
 514                         nr_segments += n_segs;
 515                 }
 516                 if (nr_segments > SG_ALL) {
 517                         pr_debug("invalid nr_seg = %d\n", nr_segments);
 518                         return -EINVAL;
 519                 }
 520         }
 521
 522         /* free of (sgl) in fast_flush_area() */
 523         pending_req->sgl = kmalloc_array(nr_segments,
 524                                         sizeof(struct scatterlist), GFP_KERNEL);
 525         if (!pending_req->sgl)
 526                 return -ENOMEM;
 527
 528         sg_init_table(pending_req->sgl, nr_segments);
 529         pending_req->n_sg = nr_segments;
 530
 531         flags = GNTMAP_host_map;
 532         if (pending_req->sc_data_direction == DMA_TO_DEVICE)
 533                 flags |= GNTMAP_readonly;
 534
 535         pg = pending_req->pages + nr_sgl;
 536         grant = pending_req->grant_handles + nr_sgl;
 537         if (!nr_sgl) {
 538                 seg = ring_req->seg;
 539                 err = scsiback_gnttab_data_map_list(pending_req, seg,
 540                         pg, grant, nr_segments, flags);
 541                 if (err)
 542                         return err;
 543         } else {
 544                 for (i = 0; i < nr_sgl; i++) {
 545                         seg = (struct scsiif_request_segment *)(
 546                               vaddr(pending_req, i) + ring_req->seg[i].offset);
 547                         n_segs = ring_req->seg[i].length /
 548                                  sizeof(struct scsiif_request_segment);
 549                         err = scsiback_gnttab_data_map_list(pending_req, seg,
 550                                 pg, grant, n_segs, flags);
 551                         if (err)
 552                                 return err;
 553                         pg += n_segs;
 554                         grant += n_segs;
 555                 }
 556                 end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
 557                 seg = (struct scsiif_request_segment *)end_seg;
 558                 end_seg += ring_req->seg[0].length;
 559                 pg = pending_req->pages + nr_sgl;
 560         }
 561
 562         for_each_sg(pending_req->sgl, sg, nr_segments, i) {
 563                 sg_set_page(sg, pg[i], seg->length, seg->offset);
 564                 pending_req->data_len += seg->length;
 565                 seg++;
 566                 if (nr_sgl && (unsigned long)seg >= end_seg) {
 567                         i_seg++;
 568                         end_seg = vaddr(pending_req, i_seg) +
 569                                   ring_req->seg[i_seg].offset;
 570                         seg = (struct scsiif_request_segment *)end_seg;
 571                         end_seg += ring_req->seg[i_seg].length;
 572                 }
 573                 if (sg->offset >= PAGE_SIZE ||
 574                     sg->length > PAGE_SIZE ||
 575                     sg->offset + sg->length > PAGE_SIZE)
 576                         return -EINVAL;
 577         }
 578
 579         return 0;
 580 }
 581
 582 static void scsiback_disconnect(struct vscsibk_info *info)
 583 {
 584         wait_event(info->waiting_to_free,
 585                 atomic_read(&info->nr_unreplied_reqs) == 0);
 586
 587         unbind_from_irqhandler(info->irq, info);
 588         info->irq = 0;
 589         xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
 590 }
 591
 592 static void scsiback_device_action(struct vscsibk_pend *pending_req,
 593         enum tcm_tmreq_table act, int tag)
 594 {
 595         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 596         struct scsiback_nexus *nexus = tpg->tpg_nexus;
 597         struct se_cmd *se_cmd = &pending_req->se_cmd;
 598         u64 unpacked_lun = pending_req->v2p->lun;
 599         int rc, err = FAILED;
 600
 601         init_completion(&pending_req->tmr_done);
 602
 603         rc = target_submit_tmr(&pending_req->se_cmd, nexus->tvn_se_sess,
 604                                &pending_req->sense_buffer[0],
 605                                unpacked_lun, NULL, act, GFP_KERNEL,
 606                                tag, TARGET_SCF_ACK_KREF);
 607         if (rc)
 608                 goto err;
 609
 610         wait_for_completion(&pending_req->tmr_done);
 611
 612         err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
 613                 SUCCESS : FAILED;
 614
 615         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 616         transport_generic_free_cmd(&pending_req->se_cmd, 0);
 617         return;
 618
 619 err:
 620         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 621 }
 622
 623 /*
 624   Perform virtual to physical translation
 625 */
 626 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
 627                         struct ids_tuple *v)
 628 {
 629         struct v2p_entry *entry;
 630         struct list_head *head = &(info->v2p_entry_lists);
 631         unsigned long flags;
 632
 633         spin_lock_irqsave(&info->v2p_lock, flags);
 634         list_for_each_entry(entry, head, l) {
 635                 if ((entry->v.chn == v->chn) &&
 636                     (entry->v.tgt == v->tgt) &&
 637                     (entry->v.lun == v->lun)) {
 638                         kref_get(&entry->kref);
 639                         goto out;
 640                 }
 641         }
 642         entry = NULL;
 643
 644 out:
 645         spin_unlock_irqrestore(&info->v2p_lock, flags);
 646         return entry;
 647 }
 648
 649 static struct vscsibk_pend *scsiback_get_pend_req(struct vscsiif_back_ring *ring,
 650                                 struct v2p_entry *v2p)
 651 {
 652         struct scsiback_tpg *tpg = v2p->tpg;
 653         struct scsiback_nexus *nexus = tpg->tpg_nexus;
 654         struct se_session *se_sess = nexus->tvn_se_sess;
 655         struct vscsibk_pend *req;
 656         int tag, i;
 657
 658         tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
 659         if (tag < 0) {
 660                 pr_err("Unable to obtain tag for vscsiif_request\n");
 661                 return ERR_PTR(-ENOMEM);
 662         }
 663
 664         req = &((struct vscsibk_pend *)se_sess->sess_cmd_map)[tag];
 665         memset(req, 0, sizeof(*req));
 666         req->se_cmd.map_tag = tag;
 667
 668         for (i = 0; i < VSCSI_MAX_GRANTS; i++)
 669                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 670
 671         return req;
 672 }
 673
 674 static struct vscsibk_pend *prepare_pending_reqs(struct vscsibk_info *info,
 675                                 struct vscsiif_back_ring *ring,
 676                                 struct vscsiif_request *ring_req)
 677 {
 678         struct vscsibk_pend *pending_req;
 679         struct v2p_entry *v2p;
 680         struct ids_tuple vir;
 681
 682         /* request range check from frontend */
 683         if ((ring_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
 684                 (ring_req->sc_data_direction != DMA_TO_DEVICE) &&
 685                 (ring_req->sc_data_direction != DMA_FROM_DEVICE) &&
 686                 (ring_req->sc_data_direction != DMA_NONE)) {
 687                 pr_debug("invalid parameter data_dir = %d\n",
 688                         ring_req->sc_data_direction);
 689                 return ERR_PTR(-EINVAL);
 690         }
 691         if (ring_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
 692                 pr_debug("invalid parameter cmd_len = %d\n",
 693                         ring_req->cmd_len);
 694                 return ERR_PTR(-EINVAL);
 695         }
 696
 697         vir.chn = ring_req->channel;
 698         vir.tgt = ring_req->id;
 699         vir.lun = ring_req->lun;
 700
 701         v2p = scsiback_do_translation(info, &vir);
 702         if (!v2p) {
 703                 pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
 704                          vir.chn, vir.tgt, vir.lun);
 705                 return ERR_PTR(-ENODEV);
 706         }
 707
 708         pending_req = scsiback_get_pend_req(ring, v2p);
 709         if (IS_ERR(pending_req)) {
 710                 kref_put(&v2p->kref, scsiback_free_translation_entry);
 711                 return ERR_PTR(-ENOMEM);
 712         }
 713         pending_req->rqid = ring_req->rqid;
 714         pending_req->info = info;
 715         pending_req->v2p = v2p;
 716         pending_req->sc_data_direction = ring_req->sc_data_direction;
 717         pending_req->cmd_len = ring_req->cmd_len;
 718         memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
 719
 720         return pending_req;
 721 }
 722
 723 static int scsiback_do_cmd_fn(struct vscsibk_info *info,
 724                               unsigned int *eoi_flags)
 725 {
 726         struct vscsiif_back_ring *ring = &info->ring;
 727         struct vscsiif_request ring_req;
 728         struct vscsibk_pend *pending_req;
 729         RING_IDX rc, rp;
 730         int more_to_do;
 731         uint32_t result;
 732
 733         rc = ring->req_cons;
 734         rp = ring->sring->req_prod;
 735         rmb();  /* guest system is accessing ring, too */
 736
 737         if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
 738                 rc = ring->rsp_prod_pvt;
 739                 pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 740                            info->domid, rp, rc, rp - rc);
 741                 return -EINVAL;
 742         }
 743
 744         while ((rc != rp)) {
 745                 *eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS;
 746
 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         int rc;
 806         unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
 807
 808         while ((rc = scsiback_do_cmd_fn(info, &eoi_flags)) > 0)
 809                 cond_resched();
 810
 811         /* In case of a ring error we keep the event channel masked. */
 812         if (!rc)
 813                 xen_irq_lateeoi(irq, eoi_flags);
 814
 815         return IRQ_HANDLED;
 816 }
 817
 818 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 819                         evtchn_port_t evtchn)
 820 {
 821         void *area;
 822         struct vscsiif_sring *sring;
 823         int err;
 824
 825         if (info->irq)
 826                 return -1;
 827
 828         err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 829         if (err)
 830                 return err;
 831
 832         sring = (struct vscsiif_sring *)area;
 833         BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 834
 835         err = bind_interdomain_evtchn_to_irq_lateeoi(info->domid, evtchn);
 836         if (err < 0)
 837                 goto unmap_page;
 838
 839         info->irq = err;
 840
 841         err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
 842                                    IRQF_ONESHOT, "vscsiif-backend", info);
 843         if (err)
 844                 goto free_irq;
 845
 846         return 0;
 847
 848 free_irq:
 849         unbind_from_irqhandler(info->irq, info);
 850         info->irq = 0;
 851 unmap_page:
 852         xenbus_unmap_ring_vfree(info->dev, area);
 853
 854         return err;
 855 }
 856
 857 static int scsiback_map(struct vscsibk_info *info)
 858 {
 859         struct xenbus_device *dev = info->dev;
 860         unsigned int ring_ref, evtchn;
 861         int err;
 862
 863         err = xenbus_gather(XBT_NIL, dev->otherend,
 864                         "ring-ref", "%u", &ring_ref,
 865                         "event-channel", "%u", &evtchn, NULL);
 866         if (err) {
 867                 xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
 868                 return err;
 869         }
 870
 871         return scsiback_init_sring(info, ring_ref, evtchn);
 872 }
 873
 874 /*
 875   Check for a translation entry being present
 876 */
 877 static struct v2p_entry *scsiback_chk_translation_entry(
 878         struct vscsibk_info *info, struct ids_tuple *v)
 879 {
 880         struct list_head *head = &(info->v2p_entry_lists);
 881         struct v2p_entry *entry;
 882
 883         list_for_each_entry(entry, head, l)
 884                 if ((entry->v.chn == v->chn) &&
 885                     (entry->v.tgt == v->tgt) &&
 886                     (entry->v.lun == v->lun))
 887                         return entry;
 888
 889         return NULL;
 890 }
 891
 892 /*
 893   Add a new translation entry
 894 */
 895 static int scsiback_add_translation_entry(struct vscsibk_info *info,
 896                                           char *phy, struct ids_tuple *v)
 897 {
 898         int err = 0;
 899         struct v2p_entry *new;
 900         unsigned long flags;
 901         char *lunp;
 902         unsigned long long unpacked_lun;
 903         struct se_lun *se_lun;
 904         struct scsiback_tpg *tpg_entry, *tpg = NULL;
 905         char *error = "doesn't exist";
 906
 907         lunp = strrchr(phy, ':');
 908         if (!lunp) {
 909                 pr_err("illegal format of physical device %s\n", phy);
 910                 return -EINVAL;
 911         }
 912         *lunp = 0;
 913         lunp++;
 914         err = kstrtoull(lunp, 10, &unpacked_lun);
 915         if (err < 0) {
 916                 pr_err("lun number not valid: %s\n", lunp);
 917                 return err;
 918         }
 919
 920         mutex_lock(&scsiback_mutex);
 921         list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
 922                 if (!strcmp(phy, tpg_entry->tport->tport_name) ||
 923                     !strcmp(phy, tpg_entry->param_alias)) {
 924                         mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
 925                         hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
 926                                 if (se_lun->unpacked_lun == unpacked_lun) {
 927                                         if (!tpg_entry->tpg_nexus)
 928                                                 error = "nexus undefined";
 929                                         else
 930                                                 tpg = tpg_entry;
 931                                         break;
 932                                 }
 933                         }
 934                         mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
 935                         break;
 936                 }
 937         }
 938         if (tpg) {
 939                 mutex_lock(&tpg->tv_tpg_mutex);
 940                 tpg->tv_tpg_fe_count++;
 941                 mutex_unlock(&tpg->tv_tpg_mutex);
 942         }
 943         mutex_unlock(&scsiback_mutex);
 944
 945         if (!tpg) {
 946                 pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
 947                 return -ENODEV;
 948         }
 949
 950         new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
 951         if (new == NULL) {
 952                 err = -ENOMEM;
 953                 goto out_free;
 954         }
 955
 956         spin_lock_irqsave(&info->v2p_lock, flags);
 957
 958         /* Check double assignment to identical virtual ID */
 959         if (scsiback_chk_translation_entry(info, v)) {
 960                 pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 961                 err = -EEXIST;
 962                 goto out;
 963         }
 964
 965         /* Create a new translation entry and add to the list */
 966         kref_init(&new->kref);
 967         new->v = *v;
 968         new->tpg = tpg;
 969         new->lun = unpacked_lun;
 970         list_add_tail(&new->l, &info->v2p_entry_lists);
 971
 972 out:
 973         spin_unlock_irqrestore(&info->v2p_lock, flags);
 974
 975 out_free:
 976         if (err) {
 977                 mutex_lock(&tpg->tv_tpg_mutex);
 978                 tpg->tv_tpg_fe_count--;
 979                 mutex_unlock(&tpg->tv_tpg_mutex);
 980                 kfree(new);
 981         }
 982
 983         return err;
 984 }
 985
 986 static void __scsiback_del_translation_entry(struct v2p_entry *entry)
 987 {
 988         list_del(&entry->l);
 989         kref_put(&entry->kref, scsiback_free_translation_entry);
 990 }
 991
 992 /*
 993   Delete the translation entry specified
 994 */
 995 static int scsiback_del_translation_entry(struct vscsibk_info *info,
 996                                           struct ids_tuple *v)
 997 {
 998         struct v2p_entry *entry;
 999         unsigned long flags;
1000         int ret = 0;
1001
1002         spin_lock_irqsave(&info->v2p_lock, flags);
1003         /* Find out the translation entry specified */
1004         entry = scsiback_chk_translation_entry(info, v);
1005         if (entry)
1006                 __scsiback_del_translation_entry(entry);
1007         else
1008                 ret = -ENOENT;
1009
1010         spin_unlock_irqrestore(&info->v2p_lock, flags);
1011         return ret;
1012 }
1013
1014 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
1015                                 char *phy, struct ids_tuple *vir, int try)
1016 {
1017         struct v2p_entry *entry;
1018         unsigned long flags;
1019         int err;
1020
1021         if (try) {
1022                 spin_lock_irqsave(&info->v2p_lock, flags);
1023                 entry = scsiback_chk_translation_entry(info, vir);
1024                 spin_unlock_irqrestore(&info->v2p_lock, flags);
1025                 if (entry)
1026                         return;
1027         }
1028         if (!scsiback_add_translation_entry(info, phy, vir)) {
1029                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1030                                   "%d", XenbusStateInitialised)) {
1031                         pr_err("xenbus_printf error %s\n", state);
1032                         scsiback_del_translation_entry(info, vir);
1033                 }
1034         } else if (!try) {
1035                 err = xenbus_printf(XBT_NIL, info->dev->nodename, state,
1036                               "%d", XenbusStateClosed);
1037                 if (err)
1038                         xenbus_dev_error(info->dev, err,
1039                                 "%s: writing %s", __func__, state);
1040         }
1041 }
1042
1043 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1044                                 struct ids_tuple *vir)
1045 {
1046         if (!scsiback_del_translation_entry(info, vir)) {
1047                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1048                                   "%d", XenbusStateClosed))
1049                         pr_err("xenbus_printf error %s\n", state);
1050         }
1051 }
1052
1053 #define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1054 #define VSCSIBACK_OP_UPDATEDEV_STATE    2
1055
1056 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1057                                      char *ent)
1058 {
1059         int err;
1060         struct ids_tuple vir;
1061         char *val;
1062         int device_state;
1063         char phy[VSCSI_NAMELEN];
1064         char str[64];
1065         char state[64];
1066         struct xenbus_device *dev = info->dev;
1067
1068         /* read status */
1069         snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1070         err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1071         if (XENBUS_EXIST_ERR(err))
1072                 return;
1073
1074         /* physical SCSI device */
1075         snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1076         val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1077         if (IS_ERR(val)) {
1078                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1079                               "%d", XenbusStateClosed);
1080                 if (err)
1081                         xenbus_dev_error(info->dev, err,
1082                                 "%s: writing %s", __func__, state);
1083                 return;
1084         }
1085         strlcpy(phy, val, VSCSI_NAMELEN);
1086         kfree(val);
1087
1088         /* virtual SCSI device */
1089         snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1090         err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1091                            &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1092         if (XENBUS_EXIST_ERR(err)) {
1093                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1094                               "%d", XenbusStateClosed);
1095                 if (err)
1096                         xenbus_dev_error(info->dev, err,
1097                                 "%s: writing %s", __func__, state);
1098                 return;
1099         }
1100
1101         switch (op) {
1102         case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1103                 switch (device_state) {
1104                 case XenbusStateInitialising:
1105                         scsiback_do_add_lun(info, state, phy, &vir, 0);
1106                         break;
1107                 case XenbusStateConnected:
1108                         scsiback_do_add_lun(info, state, phy, &vir, 1);
1109                         break;
1110                 case XenbusStateClosing:
1111                         scsiback_do_del_lun(info, state, &vir);
1112                         break;
1113                 default:
1114                         break;
1115                 }
1116                 break;
1117
1118         case VSCSIBACK_OP_UPDATEDEV_STATE:
1119                 if (device_state == XenbusStateInitialised) {
1120                         /* modify vscsi-devs/dev-x/state */
1121                         if (xenbus_printf(XBT_NIL, dev->nodename, state,
1122                                           "%d", XenbusStateConnected)) {
1123                                 pr_err("xenbus_printf error %s\n", str);
1124                                 scsiback_del_translation_entry(info, &vir);
1125                                 xenbus_printf(XBT_NIL, dev->nodename, state,
1126                                               "%d", XenbusStateClosed);
1127                         }
1128                 }
1129                 break;
1130         /* When it is necessary, processing is added here. */
1131         default:
1132                 break;
1133         }
1134 }
1135
1136 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1137 {
1138         int i;
1139         char **dir;
1140         unsigned int ndir = 0;
1141
1142         dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1143                                &ndir);
1144         if (IS_ERR(dir))
1145                 return;
1146
1147         for (i = 0; i < ndir; i++)
1148                 scsiback_do_1lun_hotplug(info, op, dir[i]);
1149
1150         kfree(dir);
1151 }
1152
1153 static void scsiback_frontend_changed(struct xenbus_device *dev,
1154                                         enum xenbus_state frontend_state)
1155 {
1156         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1157
1158         switch (frontend_state) {
1159         case XenbusStateInitialising:
1160                 break;
1161
1162         case XenbusStateInitialised:
1163                 if (scsiback_map(info))
1164                         break;
1165
1166                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1167                 xenbus_switch_state(dev, XenbusStateConnected);
1168                 break;
1169
1170         case XenbusStateConnected:
1171                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1172
1173                 if (dev->state == XenbusStateConnected)
1174                         break;
1175
1176                 xenbus_switch_state(dev, XenbusStateConnected);
1177                 break;
1178
1179         case XenbusStateClosing:
1180                 if (info->irq)
1181                         scsiback_disconnect(info);
1182
1183                 xenbus_switch_state(dev, XenbusStateClosing);
1184                 break;
1185
1186         case XenbusStateClosed:
1187                 xenbus_switch_state(dev, XenbusStateClosed);
1188                 if (xenbus_dev_is_online(dev))
1189                         break;
1190                 /* fall through if not online */
1191         case XenbusStateUnknown:
1192                 device_unregister(&dev->dev);
1193                 break;
1194
1195         case XenbusStateReconfiguring:
1196                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1197                 xenbus_switch_state(dev, XenbusStateReconfigured);
1198
1199                 break;
1200
1201         default:
1202                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1203                                         frontend_state);
1204                 break;
1205         }
1206 }
1207
1208 /*
1209   Release the translation entry specfied
1210 */
1211 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1212 {
1213         struct v2p_entry *entry, *tmp;
1214         struct list_head *head = &(info->v2p_entry_lists);
1215         unsigned long flags;
1216
1217         spin_lock_irqsave(&info->v2p_lock, flags);
1218
1219         list_for_each_entry_safe(entry, tmp, head, l)
1220                 __scsiback_del_translation_entry(entry);
1221
1222         spin_unlock_irqrestore(&info->v2p_lock, flags);
1223 }
1224
1225 static int scsiback_remove(struct xenbus_device *dev)
1226 {
1227         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1228
1229         if (info->irq)
1230                 scsiback_disconnect(info);
1231
1232         scsiback_release_translation_entry(info);
1233
1234         dev_set_drvdata(&dev->dev, NULL);
1235
1236         return 0;
1237 }
1238
1239 static int scsiback_probe(struct xenbus_device *dev,
1240                            const struct xenbus_device_id *id)
1241 {
1242         int err;
1243
1244         struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1245                                             GFP_KERNEL);
1246
1247         pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1248
1249         if (!info) {
1250                 xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1251                 return -ENOMEM;
1252         }
1253         info->dev = dev;
1254         dev_set_drvdata(&dev->dev, info);
1255
1256         info->domid = dev->otherend_id;
1257         spin_lock_init(&info->ring_lock);
1258         atomic_set(&info->nr_unreplied_reqs, 0);
1259         init_waitqueue_head(&info->waiting_to_free);
1260         info->dev = dev;
1261         info->irq = 0;
1262         INIT_LIST_HEAD(&info->v2p_entry_lists);
1263         spin_lock_init(&info->v2p_lock);
1264
1265         err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1266                             SG_ALL);
1267         if (err)
1268                 xenbus_dev_error(dev, err, "writing feature-sg-grant");
1269
1270         err = xenbus_switch_state(dev, XenbusStateInitWait);
1271         if (err)
1272                 goto fail;
1273
1274         return 0;
1275
1276 fail:
1277         pr_warn("%s failed\n", __func__);
1278         scsiback_remove(dev);
1279
1280         return err;
1281 }
1282
1283 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1284 {
1285         switch (tport->tport_proto_id) {
1286         case SCSI_PROTOCOL_SAS:
1287                 return "SAS";
1288         case SCSI_PROTOCOL_FCP:
1289                 return "FCP";
1290         case SCSI_PROTOCOL_ISCSI:
1291                 return "iSCSI";
1292         default:
1293                 break;
1294         }
1295
1296         return "Unknown";
1297 }
1298
1299 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1300 {
1301         struct scsiback_tpg *tpg = container_of(se_tpg,
1302                                 struct scsiback_tpg, se_tpg);
1303         struct scsiback_tport *tport = tpg->tport;
1304
1305         return &tport->tport_name[0];
1306 }
1307
1308 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1309 {
1310         struct scsiback_tpg *tpg = container_of(se_tpg,
1311                                 struct scsiback_tpg, se_tpg);
1312         return tpg->tport_tpgt;
1313 }
1314
1315 static struct se_wwn *
1316 scsiback_make_tport(struct target_fabric_configfs *tf,
1317                      struct config_group *group,
1318                      const char *name)
1319 {
1320         struct scsiback_tport *tport;
1321         char *ptr;
1322         u64 wwpn = 0;
1323         int off = 0;
1324
1325         tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1326         if (!tport)
1327                 return ERR_PTR(-ENOMEM);
1328
1329         tport->tport_wwpn = wwpn;
1330         /*
1331          * Determine the emulated Protocol Identifier and Target Port Name
1332          * based on the incoming configfs directory name.
1333          */
1334         ptr = strstr(name, "naa.");
1335         if (ptr) {
1336                 tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1337                 goto check_len;
1338         }
1339         ptr = strstr(name, "fc.");
1340         if (ptr) {
1341                 tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1342                 off = 3; /* Skip over "fc." */
1343                 goto check_len;
1344         }
1345         ptr = strstr(name, "iqn.");
1346         if (ptr) {
1347                 tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1348                 goto check_len;
1349         }
1350
1351         pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1352         kfree(tport);
1353         return ERR_PTR(-EINVAL);
1354
1355 check_len:
1356         if (strlen(name) >= VSCSI_NAMELEN) {
1357                 pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1358                         scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1359                 kfree(tport);
1360                 return ERR_PTR(-EINVAL);
1361         }
1362         snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1363
1364         pr_debug("Allocated emulated Target %s Address: %s\n",
1365                  scsiback_dump_proto_id(tport), name);
1366
1367         return &tport->tport_wwn;
1368 }
1369
1370 static void scsiback_drop_tport(struct se_wwn *wwn)
1371 {
1372         struct scsiback_tport *tport = container_of(wwn,
1373                                 struct scsiback_tport, tport_wwn);
1374
1375         pr_debug("Deallocating emulated Target %s Address: %s\n",
1376                  scsiback_dump_proto_id(tport), tport->tport_name);
1377
1378         kfree(tport);
1379 }
1380
1381 static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1382 {
1383         return 1;
1384 }
1385
1386 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1387 {
1388         return transport_generic_free_cmd(se_cmd, 0);
1389 }
1390
1391 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1392 {
1393         struct se_session *se_sess = se_cmd->se_sess;
1394
1395         percpu_ida_free(&se_sess->sess_tag_pool, se_cmd->map_tag);
1396 }
1397
1398 static u32 scsiback_sess_get_index(struct se_session *se_sess)
1399 {
1400         return 0;
1401 }
1402
1403 static int scsiback_write_pending(struct se_cmd *se_cmd)
1404 {
1405         /* Go ahead and process the write immediately */
1406         target_execute_cmd(se_cmd);
1407
1408         return 0;
1409 }
1410
1411 static int scsiback_write_pending_status(struct se_cmd *se_cmd)
1412 {
1413         return 0;
1414 }
1415
1416 static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1417 {
1418 }
1419
1420 static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1421 {
1422         return 0;
1423 }
1424
1425 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1426 {
1427         struct vscsibk_pend *pending_req = container_of(se_cmd,
1428                                 struct vscsibk_pend, se_cmd);
1429
1430         pending_req->result = SAM_STAT_GOOD;
1431         scsiback_cmd_done(pending_req);
1432         return 0;
1433 }
1434
1435 static int scsiback_queue_status(struct se_cmd *se_cmd)
1436 {
1437         struct vscsibk_pend *pending_req = container_of(se_cmd,
1438                                 struct vscsibk_pend, se_cmd);
1439
1440         if (se_cmd->sense_buffer &&
1441             ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1442              (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1443                 pending_req->result = (DRIVER_SENSE << 24) |
1444                                       SAM_STAT_CHECK_CONDITION;
1445         else
1446                 pending_req->result = se_cmd->scsi_status;
1447
1448         scsiback_cmd_done(pending_req);
1449         return 0;
1450 }
1451
1452 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1453 {
1454         struct vscsibk_pend *pending_req = container_of(se_cmd,
1455                                 struct vscsibk_pend, se_cmd);
1456
1457         complete(&pending_req->tmr_done);
1458 }
1459
1460 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1461 {
1462 }
1463
1464 static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1465                                              char *page)
1466 {
1467         struct se_portal_group *se_tpg = param_to_tpg(item);
1468         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1469                                                 se_tpg);
1470         ssize_t rb;
1471
1472         mutex_lock(&tpg->tv_tpg_mutex);
1473         rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1474         mutex_unlock(&tpg->tv_tpg_mutex);
1475
1476         return rb;
1477 }
1478
1479 static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1480                                               const char *page, size_t count)
1481 {
1482         struct se_portal_group *se_tpg = param_to_tpg(item);
1483         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1484                                                 se_tpg);
1485         int len;
1486
1487         if (strlen(page) >= VSCSI_NAMELEN) {
1488                 pr_err("param alias: %s, exceeds max: %d\n", page,
1489                         VSCSI_NAMELEN);
1490                 return -EINVAL;
1491         }
1492
1493         mutex_lock(&tpg->tv_tpg_mutex);
1494         len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1495         if (tpg->param_alias[len - 1] == '\n')
1496                 tpg->param_alias[len - 1] = '\0';
1497         mutex_unlock(&tpg->tv_tpg_mutex);
1498
1499         return count;
1500 }
1501
1502 CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1503
1504 static struct configfs_attribute *scsiback_param_attrs[] = {
1505         &scsiback_tpg_param_attr_alias,
1506         NULL,
1507 };
1508
1509 static int scsiback_alloc_sess_cb(struct se_portal_group *se_tpg,
1510                                   struct se_session *se_sess, void *p)
1511 {
1512         struct scsiback_tpg *tpg = container_of(se_tpg,
1513                                 struct scsiback_tpg, se_tpg);
1514
1515         tpg->tpg_nexus = p;
1516         return 0;
1517 }
1518
1519 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1520                                 const char *name)
1521 {
1522         struct scsiback_nexus *tv_nexus;
1523         int ret = 0;
1524
1525         mutex_lock(&tpg->tv_tpg_mutex);
1526         if (tpg->tpg_nexus) {
1527                 pr_debug("tpg->tpg_nexus already exists\n");
1528                 ret = -EEXIST;
1529                 goto out_unlock;
1530         }
1531
1532         tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1533         if (!tv_nexus) {
1534                 ret = -ENOMEM;
1535                 goto out_unlock;
1536         }
1537
1538         tv_nexus->tvn_se_sess = target_alloc_session(&tpg->se_tpg,
1539                                                      VSCSI_DEFAULT_SESSION_TAGS,
1540                                                      sizeof(struct vscsibk_pend),
1541                                                      TARGET_PROT_NORMAL, name,
1542                                                      tv_nexus, scsiback_alloc_sess_cb);
1543         if (IS_ERR(tv_nexus->tvn_se_sess)) {
1544                 kfree(tv_nexus);
1545                 ret = -ENOMEM;
1546                 goto out_unlock;
1547         }
1548
1549 out_unlock:
1550         mutex_unlock(&tpg->tv_tpg_mutex);
1551         return ret;
1552 }
1553
1554 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1555 {
1556         struct se_session *se_sess;
1557         struct scsiback_nexus *tv_nexus;
1558
1559         mutex_lock(&tpg->tv_tpg_mutex);
1560         tv_nexus = tpg->tpg_nexus;
1561         if (!tv_nexus) {
1562                 mutex_unlock(&tpg->tv_tpg_mutex);
1563                 return -ENODEV;
1564         }
1565
1566         se_sess = tv_nexus->tvn_se_sess;
1567         if (!se_sess) {
1568                 mutex_unlock(&tpg->tv_tpg_mutex);
1569                 return -ENODEV;
1570         }
1571
1572         if (tpg->tv_tpg_port_count != 0) {
1573                 mutex_unlock(&tpg->tv_tpg_mutex);
1574                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1575                         tpg->tv_tpg_port_count);
1576                 return -EBUSY;
1577         }
1578
1579         if (tpg->tv_tpg_fe_count != 0) {
1580                 mutex_unlock(&tpg->tv_tpg_mutex);
1581                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1582                         tpg->tv_tpg_fe_count);
1583                 return -EBUSY;
1584         }
1585
1586         pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1587                 scsiback_dump_proto_id(tpg->tport),
1588                 tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1589
1590         /*
1591          * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1592          */
1593         transport_deregister_session(tv_nexus->tvn_se_sess);
1594         tpg->tpg_nexus = NULL;
1595         mutex_unlock(&tpg->tv_tpg_mutex);
1596
1597         kfree(tv_nexus);
1598         return 0;
1599 }
1600
1601 static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1602 {
1603         struct se_portal_group *se_tpg = to_tpg(item);
1604         struct scsiback_tpg *tpg = container_of(se_tpg,
1605                                 struct scsiback_tpg, se_tpg);
1606         struct scsiback_nexus *tv_nexus;
1607         ssize_t ret;
1608
1609         mutex_lock(&tpg->tv_tpg_mutex);
1610         tv_nexus = tpg->tpg_nexus;
1611         if (!tv_nexus) {
1612                 mutex_unlock(&tpg->tv_tpg_mutex);
1613                 return -ENODEV;
1614         }
1615         ret = snprintf(page, PAGE_SIZE, "%s\n",
1616                         tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1617         mutex_unlock(&tpg->tv_tpg_mutex);
1618
1619         return ret;
1620 }
1621
1622 static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
1623                 const char *page, size_t count)
1624 {
1625         struct se_portal_group *se_tpg = to_tpg(item);
1626         struct scsiback_tpg *tpg = container_of(se_tpg,
1627                                 struct scsiback_tpg, se_tpg);
1628         struct scsiback_tport *tport_wwn = tpg->tport;
1629         unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1630         int ret;
1631         /*
1632          * Shutdown the active I_T nexus if 'NULL' is passed.
1633          */
1634         if (!strncmp(page, "NULL", 4)) {
1635                 ret = scsiback_drop_nexus(tpg);
1636                 return (!ret) ? count : ret;
1637         }
1638         /*
1639          * Otherwise make sure the passed virtual Initiator port WWN matches
1640          * the fabric protocol_id set in scsiback_make_tport(), and call
1641          * scsiback_make_nexus().
1642          */
1643         if (strlen(page) >= VSCSI_NAMELEN) {
1644                 pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1645                         page, VSCSI_NAMELEN);
1646                 return -EINVAL;
1647         }
1648         snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1649
1650         ptr = strstr(i_port, "naa.");
1651         if (ptr) {
1652                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1653                         pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1654                                 i_port, scsiback_dump_proto_id(tport_wwn));
1655                         return -EINVAL;
1656                 }
1657                 port_ptr = &i_port[0];
1658                 goto check_newline;
1659         }
1660         ptr = strstr(i_port, "fc.");
1661         if (ptr) {
1662                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1663                         pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1664                                 i_port, scsiback_dump_proto_id(tport_wwn));
1665                         return -EINVAL;
1666                 }
1667                 port_ptr = &i_port[3]; /* Skip over "fc." */
1668                 goto check_newline;
1669         }
1670         ptr = strstr(i_port, "iqn.");
1671         if (ptr) {
1672                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1673                         pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1674                                 i_port, scsiback_dump_proto_id(tport_wwn));
1675                         return -EINVAL;
1676                 }
1677                 port_ptr = &i_port[0];
1678                 goto check_newline;
1679         }
1680         pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1681                 i_port);
1682         return -EINVAL;
1683         /*
1684          * Clear any trailing newline for the NAA WWN
1685          */
1686 check_newline:
1687         if (i_port[strlen(i_port) - 1] == '\n')
1688                 i_port[strlen(i_port) - 1] = '\0';
1689
1690         ret = scsiback_make_nexus(tpg, port_ptr);
1691         if (ret < 0)
1692                 return ret;
1693
1694         return count;
1695 }
1696
1697 CONFIGFS_ATTR(scsiback_tpg_, nexus);
1698
1699 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1700         &scsiback_tpg_attr_nexus,
1701         NULL,
1702 };
1703
1704 static ssize_t
1705 scsiback_wwn_version_show(struct config_item *item, char *page)
1706 {
1707         return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1708                 UTS_RELEASE"\n",
1709                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1710 }
1711
1712 CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1713
1714 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1715         &scsiback_wwn_attr_version,
1716         NULL,
1717 };
1718
1719 static char *scsiback_get_fabric_name(void)
1720 {
1721         return "xen-pvscsi";
1722 }
1723
1724 static int scsiback_port_link(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         return 0;
1735 }
1736
1737 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1738                                   struct se_lun *lun)
1739 {
1740         struct scsiback_tpg *tpg = container_of(se_tpg,
1741                                 struct scsiback_tpg, se_tpg);
1742
1743         mutex_lock(&tpg->tv_tpg_mutex);
1744         tpg->tv_tpg_port_count--;
1745         mutex_unlock(&tpg->tv_tpg_mutex);
1746 }
1747
1748 static struct se_portal_group *
1749 scsiback_make_tpg(struct se_wwn *wwn,
1750                    struct config_group *group,
1751                    const char *name)
1752 {
1753         struct scsiback_tport *tport = container_of(wwn,
1754                         struct scsiback_tport, tport_wwn);
1755
1756         struct scsiback_tpg *tpg;
1757         u16 tpgt;
1758         int ret;
1759
1760         if (strstr(name, "tpgt_") != name)
1761                 return ERR_PTR(-EINVAL);
1762         ret = kstrtou16(name + 5, 10, &tpgt);
1763         if (ret)
1764                 return ERR_PTR(ret);
1765
1766         tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1767         if (!tpg)
1768                 return ERR_PTR(-ENOMEM);
1769
1770         mutex_init(&tpg->tv_tpg_mutex);
1771         INIT_LIST_HEAD(&tpg->tv_tpg_list);
1772         INIT_LIST_HEAD(&tpg->info_list);
1773         tpg->tport = tport;
1774         tpg->tport_tpgt = tpgt;
1775
1776         ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1777         if (ret < 0) {
1778                 kfree(tpg);
1779                 return NULL;
1780         }
1781         mutex_lock(&scsiback_mutex);
1782         list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1783         mutex_unlock(&scsiback_mutex);
1784
1785         return &tpg->se_tpg;
1786 }
1787
1788 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1789 {
1790         struct scsiback_tpg *tpg = container_of(se_tpg,
1791                                 struct scsiback_tpg, se_tpg);
1792
1793         mutex_lock(&scsiback_mutex);
1794         list_del(&tpg->tv_tpg_list);
1795         mutex_unlock(&scsiback_mutex);
1796         /*
1797          * Release the virtual I_T Nexus for this xen-pvscsi TPG
1798          */
1799         scsiback_drop_nexus(tpg);
1800         /*
1801          * Deregister the se_tpg from TCM.
1802          */
1803         core_tpg_deregister(se_tpg);
1804         kfree(tpg);
1805 }
1806
1807 static int scsiback_check_true(struct se_portal_group *se_tpg)
1808 {
1809         return 1;
1810 }
1811
1812 static int scsiback_check_false(struct se_portal_group *se_tpg)
1813 {
1814         return 0;
1815 }
1816
1817 static const struct target_core_fabric_ops scsiback_ops = {
1818         .module                         = THIS_MODULE,
1819         .name                           = "xen-pvscsi",
1820         .get_fabric_name                = scsiback_get_fabric_name,
1821         .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1822         .tpg_get_tag                    = scsiback_get_tag,
1823         .tpg_check_demo_mode            = scsiback_check_true,
1824         .tpg_check_demo_mode_cache      = scsiback_check_true,
1825         .tpg_check_demo_mode_write_protect = scsiback_check_false,
1826         .tpg_check_prod_mode_write_protect = scsiback_check_false,
1827         .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1828         .check_stop_free                = scsiback_check_stop_free,
1829         .release_cmd                    = scsiback_release_cmd,
1830         .sess_get_index                 = scsiback_sess_get_index,
1831         .sess_get_initiator_sid         = NULL,
1832         .write_pending                  = scsiback_write_pending,
1833         .write_pending_status           = scsiback_write_pending_status,
1834         .set_default_node_attributes    = scsiback_set_default_node_attrs,
1835         .get_cmd_state                  = scsiback_get_cmd_state,
1836         .queue_data_in                  = scsiback_queue_data_in,
1837         .queue_status                   = scsiback_queue_status,
1838         .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1839         .aborted_task                   = scsiback_aborted_task,
1840         /*
1841          * Setup callers for generic logic in target_core_fabric_configfs.c
1842          */
1843         .fabric_make_wwn                = scsiback_make_tport,
1844         .fabric_drop_wwn                = scsiback_drop_tport,
1845         .fabric_make_tpg                = scsiback_make_tpg,
1846         .fabric_drop_tpg                = scsiback_drop_tpg,
1847         .fabric_post_link               = scsiback_port_link,
1848         .fabric_pre_unlink              = scsiback_port_unlink,
1849
1850         .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1851         .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1852         .tfc_tpg_param_attrs            = scsiback_param_attrs,
1853 };
1854
1855 static const struct xenbus_device_id scsiback_ids[] = {
1856         { "vscsi" },
1857         { "" }
1858 };
1859
1860 static struct xenbus_driver scsiback_driver = {
1861         .ids                    = scsiback_ids,
1862         .probe                  = scsiback_probe,
1863         .remove                 = scsiback_remove,
1864         .otherend_changed       = scsiback_frontend_changed
1865 };
1866
1867 static int __init scsiback_init(void)
1868 {
1869         int ret;
1870
1871         if (!xen_domain())
1872                 return -ENODEV;
1873
1874         pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1875                  VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1876
1877         ret = xenbus_register_backend(&scsiback_driver);
1878         if (ret)
1879                 goto out;
1880
1881         ret = target_register_template(&scsiback_ops);
1882         if (ret)
1883                 goto out_unregister_xenbus;
1884
1885         return 0;
1886
1887 out_unregister_xenbus:
1888         xenbus_unregister_driver(&scsiback_driver);
1889 out:
1890         pr_err("%s: error %d\n", __func__, ret);
1891         return ret;
1892 }
1893
1894 static void __exit scsiback_exit(void)
1895 {
1896         struct page *page;
1897
1898         while (free_pages_num) {
1899                 if (get_free_page(&page))
1900                         BUG();
1901                 gnttab_free_pages(1, &page);
1902         }
1903         target_unregister_template(&scsiback_ops);
1904         xenbus_unregister_driver(&scsiback_driver);
1905 }
1906
1907 module_init(scsiback_init);
1908 module_exit(scsiback_exit);
1909
1910 MODULE_DESCRIPTION("Xen SCSI backend driver");
1911 MODULE_LICENSE("Dual BSD/GPL");
1912 MODULE_ALIAS("xen-backend:vscsi");
1913 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");