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         struct gnttab_page_cache free_pages;
 104 };
 105
 106 /* theoretical maximum of grants for one request */
 107 #define VSCSI_MAX_GRANTS        (SG_ALL + VSCSIIF_SG_TABLESIZE)
 108
 109 /*
 110  * VSCSI_GRANT_BATCH is the maximum number of grants to be processed in one
 111  * call to map/unmap grants. Don't choose it too large, as there are arrays
 112  * with VSCSI_GRANT_BATCH elements allocated on the stack.
 113  */
 114 #define VSCSI_GRANT_BATCH       16
 115
 116 struct vscsibk_pend {
 117         uint16_t rqid;
 118
 119         uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE];
 120         uint8_t cmd_len;
 121
 122         uint8_t sc_data_direction;
 123         uint16_t n_sg;          /* real length of SG list */
 124         uint16_t n_grants;      /* SG pages and potentially SG list */
 125         uint32_t data_len;
 126         uint32_t result;
 127
 128         struct vscsibk_info *info;
 129         struct v2p_entry *v2p;
 130         struct scatterlist *sgl;
 131
 132         uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];
 133
 134         grant_handle_t grant_handles[VSCSI_MAX_GRANTS];
 135         struct page *pages[VSCSI_MAX_GRANTS];
 136
 137         struct se_cmd se_cmd;
 138
 139         struct completion tmr_done;
 140 };
 141
 142 #define VSCSI_DEFAULT_SESSION_TAGS      128
 143
 144 struct scsiback_nexus {
 145         /* Pointer to TCM session for I_T Nexus */
 146         struct se_session *tvn_se_sess;
 147 };
 148
 149 struct scsiback_tport {
 150         /* SCSI protocol the tport is providing */
 151         u8 tport_proto_id;
 152         /* Binary World Wide unique Port Name for pvscsi Target port */
 153         u64 tport_wwpn;
 154         /* ASCII formatted WWPN for pvscsi Target port */
 155         char tport_name[VSCSI_NAMELEN];
 156         /* Returned by scsiback_make_tport() */
 157         struct se_wwn tport_wwn;
 158 };
 159
 160 struct scsiback_tpg {
 161         /* scsiback port target portal group tag for TCM */
 162         u16 tport_tpgt;
 163         /* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
 164         int tv_tpg_port_count;
 165         /* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
 166         int tv_tpg_fe_count;
 167         /* list for scsiback_list */
 168         struct list_head tv_tpg_list;
 169         /* Used to protect access for tpg_nexus */
 170         struct mutex tv_tpg_mutex;
 171         /* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
 172         struct scsiback_nexus *tpg_nexus;
 173         /* Pointer back to scsiback_tport */
 174         struct scsiback_tport *tport;
 175         /* Returned by scsiback_make_tpg() */
 176         struct se_portal_group se_tpg;
 177         /* alias used in xenstore */
 178         char param_alias[VSCSI_NAMELEN];
 179         /* list of info structures related to this target portal group */
 180         struct list_head info_list;
 181 };
 182
 183 #define SCSIBACK_INVALID_HANDLE (~0)
 184
 185 static bool log_print_stat;
 186 module_param(log_print_stat, bool, 0644);
 187
 188 static int scsiback_max_buffer_pages = 1024;
 189 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
 190 MODULE_PARM_DESC(max_buffer_pages,
 191 "Maximum number of free pages to keep in backend buffer");
 192
 193 /* Global spinlock to protect scsiback TPG list */
 194 static DEFINE_MUTEX(scsiback_mutex);
 195 static LIST_HEAD(scsiback_list);
 196
 197 static void scsiback_get(struct vscsibk_info *info)
 198 {
 199         atomic_inc(&info->nr_unreplied_reqs);
 200 }
 201
 202 static void scsiback_put(struct vscsibk_info *info)
 203 {
 204         if (atomic_dec_and_test(&info->nr_unreplied_reqs))
 205                 wake_up(&info->waiting_to_free);
 206 }
 207
 208 static unsigned long vaddr_page(struct page *page)
 209 {
 210         unsigned long pfn = page_to_pfn(page);
 211
 212         return (unsigned long)pfn_to_kaddr(pfn);
 213 }
 214
 215 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
 216 {
 217         return vaddr_page(req->pages[seg]);
 218 }
 219
 220 static void scsiback_print_status(char *sense_buffer, int errors,
 221                                         struct vscsibk_pend *pending_req)
 222 {
 223         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 224
 225         pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
 226                tpg->tport->tport_name, pending_req->v2p->lun,
 227                pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
 228                host_byte(errors), driver_byte(errors));
 229 }
 230
 231 static void scsiback_fast_flush_area(struct vscsibk_pend *req)
 232 {
 233         struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
 234         struct page *pages[VSCSI_GRANT_BATCH];
 235         unsigned int i, invcount = 0;
 236         grant_handle_t handle;
 237         int err;
 238
 239         kfree(req->sgl);
 240         req->sgl = NULL;
 241         req->n_sg = 0;
 242
 243         if (!req->n_grants)
 244                 return;
 245
 246         for (i = 0; i < req->n_grants; i++) {
 247                 handle = req->grant_handles[i];
 248                 if (handle == SCSIBACK_INVALID_HANDLE)
 249                         continue;
 250                 gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
 251                                     GNTMAP_host_map, handle);
 252                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 253                 pages[invcount] = req->pages[i];
 254                 put_page(pages[invcount]);
 255                 invcount++;
 256                 if (invcount < VSCSI_GRANT_BATCH)
 257                         continue;
 258                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 259                 BUG_ON(err);
 260                 invcount = 0;
 261         }
 262
 263         if (invcount) {
 264                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 265                 BUG_ON(err);
 266         }
 267
 268         gnttab_page_cache_put(&req->info->free_pages, req->pages,
 269                               req->n_grants);
 270         req->n_grants = 0;
 271 }
 272
 273 static void scsiback_free_translation_entry(struct kref *kref)
 274 {
 275         struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
 276         struct scsiback_tpg *tpg = entry->tpg;
 277
 278         mutex_lock(&tpg->tv_tpg_mutex);
 279         tpg->tv_tpg_fe_count--;
 280         mutex_unlock(&tpg->tv_tpg_mutex);
 281
 282         kfree(entry);
 283 }
 284
 285 static void scsiback_send_response(struct vscsibk_info *info,
 286                         char *sense_buffer, int32_t result, uint32_t resid,
 287                         uint16_t rqid)
 288 {
 289         struct vscsiif_response *ring_res;
 290         int notify;
 291         struct scsi_sense_hdr sshdr;
 292         unsigned long flags;
 293         unsigned len;
 294
 295         spin_lock_irqsave(&info->ring_lock, flags);
 296
 297         ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
 298         info->ring.rsp_prod_pvt++;
 299
 300         ring_res->rslt   = result;
 301         ring_res->rqid   = rqid;
 302
 303         if (sense_buffer != NULL &&
 304             scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
 305                                  &sshdr)) {
 306                 len = min_t(unsigned, 8 + sense_buffer[7],
 307                             VSCSIIF_SENSE_BUFFERSIZE);
 308                 memcpy(ring_res->sense_buffer, sense_buffer, len);
 309                 ring_res->sense_len = len;
 310         } else {
 311                 ring_res->sense_len = 0;
 312         }
 313
 314         ring_res->residual_len = resid;
 315
 316         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
 317         spin_unlock_irqrestore(&info->ring_lock, flags);
 318
 319         if (notify)
 320                 notify_remote_via_irq(info->irq);
 321 }
 322
 323 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
 324                         uint32_t resid, struct vscsibk_pend *pending_req)
 325 {
 326         scsiback_send_response(pending_req->info, sense_buffer, result,
 327                                resid, pending_req->rqid);
 328
 329         if (pending_req->v2p)
 330                 kref_put(&pending_req->v2p->kref,
 331                          scsiback_free_translation_entry);
 332 }
 333
 334 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
 335 {
 336         struct vscsibk_info *info = pending_req->info;
 337         unsigned char *sense_buffer;
 338         unsigned int resid;
 339         int errors;
 340
 341         sense_buffer = pending_req->sense_buffer;
 342         resid        = pending_req->se_cmd.residual_count;
 343         errors       = pending_req->result;
 344
 345         if (errors && log_print_stat)
 346                 scsiback_print_status(sense_buffer, errors, pending_req);
 347
 348         scsiback_fast_flush_area(pending_req);
 349         scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
 350         scsiback_put(info);
 351         /*
 352          * Drop the extra KREF_ACK reference taken by target_submit_cmd_map_sgls()
 353          * ahead of scsiback_check_stop_free() ->  transport_generic_free_cmd()
 354          * final se_cmd->cmd_kref put.
 355          */
 356         target_put_sess_cmd(&pending_req->se_cmd);
 357 }
 358
 359 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
 360 {
 361         struct se_cmd *se_cmd = &pending_req->se_cmd;
 362         struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
 363         int rc;
 364
 365         scsiback_get(pending_req->info);
 366         se_cmd->tag = pending_req->rqid;
 367         rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,
 368                         pending_req->sense_buffer, pending_req->v2p->lun,
 369                         pending_req->data_len, 0,
 370                         pending_req->sc_data_direction, TARGET_SCF_ACK_KREF,
 371                         pending_req->sgl, pending_req->n_sg,
 372                         NULL, 0, NULL, 0);
 373         if (rc < 0) {
 374                 transport_send_check_condition_and_sense(se_cmd,
 375                                 TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
 376                 transport_generic_free_cmd(se_cmd, 0);
 377         }
 378 }
 379
 380 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 381         struct page **pg, grant_handle_t *grant, int cnt)
 382 {
 383         int err, i;
 384
 385         if (!cnt)
 386                 return 0;
 387
 388         err = gnttab_map_refs(map, NULL, pg, cnt);
 389         BUG_ON(err);
 390         for (i = 0; i < cnt; i++) {
 391                 if (unlikely(map[i].status != GNTST_okay)) {
 392                         pr_err("invalid buffer -- could not remap it\n");
 393                         map[i].handle = SCSIBACK_INVALID_HANDLE;
 394                         err = -ENOMEM;
 395                 } else {
 396                         get_page(pg[i]);
 397                 }
 398                 grant[i] = map[i].handle;
 399         }
 400         return err;
 401 }
 402
 403 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
 404                         struct scsiif_request_segment *seg, struct page **pg,
 405                         grant_handle_t *grant, int cnt, u32 flags)
 406 {
 407         int mapcount = 0, i, err = 0;
 408         struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
 409         struct vscsibk_info *info = pending_req->info;
 410
 411         for (i = 0; i < cnt; i++) {
 412                 if (gnttab_page_cache_get(&info->free_pages, pg + mapcount)) {
 413                         gnttab_page_cache_put(&info->free_pages, pg, mapcount);
 414                         pr_err("no grant page\n");
 415                         return -ENOMEM;
 416                 }
 417                 gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
 418                                   flags, seg[i].gref, info->domid);
 419                 mapcount++;
 420                 if (mapcount < VSCSI_GRANT_BATCH)
 421                         continue;
 422                 err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 423                 pg += mapcount;
 424                 grant += mapcount;
 425                 pending_req->n_grants += mapcount;
 426                 if (err)
 427                         return err;
 428                 mapcount = 0;
 429         }
 430         err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 431         pending_req->n_grants += mapcount;
 432         return err;
 433 }
 434
 435 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 436                                         struct vscsibk_pend *pending_req)
 437 {
 438         u32 flags;
 439         int i, err, n_segs, i_seg = 0;
 440         struct page **pg;
 441         struct scsiif_request_segment *seg;
 442         unsigned long end_seg = 0;
 443         unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
 444         unsigned int nr_sgl = 0;
 445         struct scatterlist *sg;
 446         grant_handle_t *grant;
 447
 448         pending_req->n_sg = 0;
 449         pending_req->n_grants = 0;
 450         pending_req->data_len = 0;
 451
 452         nr_segments &= ~VSCSIIF_SG_GRANT;
 453         if (!nr_segments)
 454                 return 0;
 455
 456         if (nr_segments > VSCSIIF_SG_TABLESIZE) {
 457                 pr_debug("invalid parameter nr_seg = %d\n",
 458                         ring_req->nr_segments);
 459                 return -EINVAL;
 460         }
 461
 462         if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
 463                 err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
 464                         pending_req->pages, pending_req->grant_handles,
 465                         nr_segments, GNTMAP_host_map | GNTMAP_readonly);
 466                 if (err)
 467                         return err;
 468                 nr_sgl = nr_segments;
 469                 nr_segments = 0;
 470                 for (i = 0; i < nr_sgl; i++) {
 471                         n_segs = ring_req->seg[i].length /
 472                                  sizeof(struct scsiif_request_segment);
 473                         if ((unsigned)ring_req->seg[i].offset +
 474                             (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
 475                             n_segs * sizeof(struct scsiif_request_segment) !=
 476                             ring_req->seg[i].length)
 477                                 return -EINVAL;
 478                         nr_segments += n_segs;
 479                 }
 480                 if (nr_segments > SG_ALL) {
 481                         pr_debug("invalid nr_seg = %d\n", nr_segments);
 482                         return -EINVAL;
 483                 }
 484         }
 485
 486         /* free of (sgl) in fast_flush_area() */
 487         pending_req->sgl = kmalloc_array(nr_segments,
 488                                         sizeof(struct scatterlist), GFP_KERNEL);
 489         if (!pending_req->sgl)
 490                 return -ENOMEM;
 491
 492         sg_init_table(pending_req->sgl, nr_segments);
 493         pending_req->n_sg = nr_segments;
 494
 495         flags = GNTMAP_host_map;
 496         if (pending_req->sc_data_direction == DMA_TO_DEVICE)
 497                 flags |= GNTMAP_readonly;
 498
 499         pg = pending_req->pages + nr_sgl;
 500         grant = pending_req->grant_handles + nr_sgl;
 501         if (!nr_sgl) {
 502                 seg = ring_req->seg;
 503                 err = scsiback_gnttab_data_map_list(pending_req, seg,
 504                         pg, grant, nr_segments, flags);
 505                 if (err)
 506                         return err;
 507         } else {
 508                 for (i = 0; i < nr_sgl; i++) {
 509                         seg = (struct scsiif_request_segment *)(
 510                               vaddr(pending_req, i) + ring_req->seg[i].offset);
 511                         n_segs = ring_req->seg[i].length /
 512                                  sizeof(struct scsiif_request_segment);
 513                         err = scsiback_gnttab_data_map_list(pending_req, seg,
 514                                 pg, grant, n_segs, flags);
 515                         if (err)
 516                                 return err;
 517                         pg += n_segs;
 518                         grant += n_segs;
 519                 }
 520                 end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
 521                 seg = (struct scsiif_request_segment *)end_seg;
 522                 end_seg += ring_req->seg[0].length;
 523                 pg = pending_req->pages + nr_sgl;
 524         }
 525
 526         for_each_sg(pending_req->sgl, sg, nr_segments, i) {
 527                 sg_set_page(sg, pg[i], seg->length, seg->offset);
 528                 pending_req->data_len += seg->length;
 529                 seg++;
 530                 if (nr_sgl && (unsigned long)seg >= end_seg) {
 531                         i_seg++;
 532                         end_seg = vaddr(pending_req, i_seg) +
 533                                   ring_req->seg[i_seg].offset;
 534                         seg = (struct scsiif_request_segment *)end_seg;
 535                         end_seg += ring_req->seg[i_seg].length;
 536                 }
 537                 if (sg->offset >= PAGE_SIZE ||
 538                     sg->length > PAGE_SIZE ||
 539                     sg->offset + sg->length > PAGE_SIZE)
 540                         return -EINVAL;
 541         }
 542
 543         return 0;
 544 }
 545
 546 static void scsiback_disconnect(struct vscsibk_info *info)
 547 {
 548         wait_event(info->waiting_to_free,
 549                 atomic_read(&info->nr_unreplied_reqs) == 0);
 550
 551         unbind_from_irqhandler(info->irq, info);
 552         info->irq = 0;
 553         xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
 554 }
 555
 556 static void scsiback_device_action(struct vscsibk_pend *pending_req,
 557         enum tcm_tmreq_table act, int tag)
 558 {
 559         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 560         struct scsiback_nexus *nexus = tpg->tpg_nexus;
 561         struct se_cmd *se_cmd = &pending_req->se_cmd;
 562         u64 unpacked_lun = pending_req->v2p->lun;
 563         int rc, err = FAILED;
 564
 565         init_completion(&pending_req->tmr_done);
 566
 567         rc = target_submit_tmr(&pending_req->se_cmd, nexus->tvn_se_sess,
 568                                &pending_req->sense_buffer[0],
 569                                unpacked_lun, NULL, act, GFP_KERNEL,
 570                                tag, TARGET_SCF_ACK_KREF);
 571         if (rc)
 572                 goto err;
 573
 574         wait_for_completion(&pending_req->tmr_done);
 575
 576         err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
 577                 SUCCESS : FAILED;
 578
 579         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 580         transport_generic_free_cmd(&pending_req->se_cmd, 0);
 581         return;
 582
 583 err:
 584         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 585 }
 586
 587 /*
 588   Perform virtual to physical translation
 589 */
 590 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
 591                         struct ids_tuple *v)
 592 {
 593         struct v2p_entry *entry;
 594         struct list_head *head = &(info->v2p_entry_lists);
 595         unsigned long flags;
 596
 597         spin_lock_irqsave(&info->v2p_lock, flags);
 598         list_for_each_entry(entry, head, l) {
 599                 if ((entry->v.chn == v->chn) &&
 600                     (entry->v.tgt == v->tgt) &&
 601                     (entry->v.lun == v->lun)) {
 602                         kref_get(&entry->kref);
 603                         goto out;
 604                 }
 605         }
 606         entry = NULL;
 607
 608 out:
 609         spin_unlock_irqrestore(&info->v2p_lock, flags);
 610         return entry;
 611 }
 612
 613 static struct vscsibk_pend *scsiback_get_pend_req(struct vscsiif_back_ring *ring,
 614                                 struct v2p_entry *v2p)
 615 {
 616         struct scsiback_tpg *tpg = v2p->tpg;
 617         struct scsiback_nexus *nexus = tpg->tpg_nexus;
 618         struct se_session *se_sess = nexus->tvn_se_sess;
 619         struct vscsibk_pend *req;
 620         int tag, cpu, i;
 621
 622         tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
 623         if (tag < 0) {
 624                 pr_err("Unable to obtain tag for vscsiif_request\n");
 625                 return ERR_PTR(-ENOMEM);
 626         }
 627
 628         req = &((struct vscsibk_pend *)se_sess->sess_cmd_map)[tag];
 629         memset(req, 0, sizeof(*req));
 630         req->se_cmd.map_tag = tag;
 631         req->se_cmd.map_cpu = cpu;
 632
 633         for (i = 0; i < VSCSI_MAX_GRANTS; i++)
 634                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 635
 636         return req;
 637 }
 638
 639 static struct vscsibk_pend *prepare_pending_reqs(struct vscsibk_info *info,
 640                                 struct vscsiif_back_ring *ring,
 641                                 struct vscsiif_request *ring_req)
 642 {
 643         struct vscsibk_pend *pending_req;
 644         struct v2p_entry *v2p;
 645         struct ids_tuple vir;
 646
 647         /* request range check from frontend */
 648         if ((ring_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
 649                 (ring_req->sc_data_direction != DMA_TO_DEVICE) &&
 650                 (ring_req->sc_data_direction != DMA_FROM_DEVICE) &&
 651                 (ring_req->sc_data_direction != DMA_NONE)) {
 652                 pr_debug("invalid parameter data_dir = %d\n",
 653                         ring_req->sc_data_direction);
 654                 return ERR_PTR(-EINVAL);
 655         }
 656         if (ring_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
 657                 pr_debug("invalid parameter cmd_len = %d\n",
 658                         ring_req->cmd_len);
 659                 return ERR_PTR(-EINVAL);
 660         }
 661
 662         vir.chn = ring_req->channel;
 663         vir.tgt = ring_req->id;
 664         vir.lun = ring_req->lun;
 665
 666         v2p = scsiback_do_translation(info, &vir);
 667         if (!v2p) {
 668                 pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
 669                          vir.chn, vir.tgt, vir.lun);
 670                 return ERR_PTR(-ENODEV);
 671         }
 672
 673         pending_req = scsiback_get_pend_req(ring, v2p);
 674         if (IS_ERR(pending_req)) {
 675                 kref_put(&v2p->kref, scsiback_free_translation_entry);
 676                 return ERR_PTR(-ENOMEM);
 677         }
 678         pending_req->rqid = ring_req->rqid;
 679         pending_req->info = info;
 680         pending_req->v2p = v2p;
 681         pending_req->sc_data_direction = ring_req->sc_data_direction;
 682         pending_req->cmd_len = ring_req->cmd_len;
 683         memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
 684
 685         return pending_req;
 686 }
 687
 688 static int scsiback_do_cmd_fn(struct vscsibk_info *info,
 689                               unsigned int *eoi_flags)
 690 {
 691         struct vscsiif_back_ring *ring = &info->ring;
 692         struct vscsiif_request ring_req;
 693         struct vscsibk_pend *pending_req;
 694         RING_IDX rc, rp;
 695         int more_to_do;
 696         uint32_t result;
 697
 698         rc = ring->req_cons;
 699         rp = ring->sring->req_prod;
 700         rmb();  /* guest system is accessing ring, too */
 701
 702         if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
 703                 rc = ring->rsp_prod_pvt;
 704                 pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 705                            info->domid, rp, rc, rp - rc);
 706                 return -EINVAL;
 707         }
 708
 709         while ((rc != rp)) {
 710                 *eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS;
 711
 712                 if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
 713                         break;
 714
 715                 RING_COPY_REQUEST(ring, rc, &ring_req);
 716                 ring->req_cons = ++rc;
 717
 718                 pending_req = prepare_pending_reqs(info, ring, &ring_req);
 719                 if (IS_ERR(pending_req)) {
 720                         switch (PTR_ERR(pending_req)) {
 721                         case -ENODEV:
 722                                 result = DID_NO_CONNECT;
 723                                 break;
 724                         default:
 725                                 result = DRIVER_ERROR;
 726                                 break;
 727                         }
 728                         scsiback_send_response(info, NULL, result << 24, 0,
 729                                                ring_req.rqid);
 730                         return 1;
 731                 }
 732
 733                 switch (ring_req.act) {
 734                 case VSCSIIF_ACT_SCSI_CDB:
 735                         if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
 736                                 scsiback_fast_flush_area(pending_req);
 737                                 scsiback_do_resp_with_sense(NULL,
 738                                                 DRIVER_ERROR << 24, 0, pending_req);
 739                                 transport_generic_free_cmd(&pending_req->se_cmd, 0);
 740                         } else {
 741                                 scsiback_cmd_exec(pending_req);
 742                         }
 743                         break;
 744                 case VSCSIIF_ACT_SCSI_ABORT:
 745                         scsiback_device_action(pending_req, TMR_ABORT_TASK,
 746                                 ring_req.ref_rqid);
 747                         break;
 748                 case VSCSIIF_ACT_SCSI_RESET:
 749                         scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
 750                         break;
 751                 default:
 752                         pr_err_ratelimited("invalid request\n");
 753                         scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24, 0,
 754                                                     pending_req);
 755                         transport_generic_free_cmd(&pending_req->se_cmd, 0);
 756                         break;
 757                 }
 758
 759                 /* Yield point for this unbounded loop. */
 760                 cond_resched();
 761         }
 762
 763         gnttab_page_cache_shrink(&info->free_pages, scsiback_max_buffer_pages);
 764
 765         RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
 766         return more_to_do;
 767 }
 768
 769 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
 770 {
 771         struct vscsibk_info *info = dev_id;
 772         int rc;
 773         unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
 774
 775         while ((rc = scsiback_do_cmd_fn(info, &eoi_flags)) > 0)
 776                 cond_resched();
 777
 778         /* In case of a ring error we keep the event channel masked. */
 779         if (!rc)
 780                 xen_irq_lateeoi(irq, eoi_flags);
 781
 782         return IRQ_HANDLED;
 783 }
 784
 785 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 786                         evtchn_port_t evtchn)
 787 {
 788         void *area;
 789         struct vscsiif_sring *sring;
 790         int err;
 791
 792         if (info->irq)
 793                 return -1;
 794
 795         err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 796         if (err)
 797                 return err;
 798
 799         sring = (struct vscsiif_sring *)area;
 800         BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 801
 802         err = bind_interdomain_evtchn_to_irq_lateeoi(info->domid, evtchn);
 803         if (err < 0)
 804                 goto unmap_page;
 805
 806         info->irq = err;
 807
 808         err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
 809                                    IRQF_ONESHOT, "vscsiif-backend", info);
 810         if (err)
 811                 goto free_irq;
 812
 813         return 0;
 814
 815 free_irq:
 816         unbind_from_irqhandler(info->irq, info);
 817         info->irq = 0;
 818 unmap_page:
 819         xenbus_unmap_ring_vfree(info->dev, area);
 820
 821         return err;
 822 }
 823
 824 static int scsiback_map(struct vscsibk_info *info)
 825 {
 826         struct xenbus_device *dev = info->dev;
 827         unsigned int ring_ref;
 828         evtchn_port_t evtchn;
 829         int err;
 830
 831         err = xenbus_gather(XBT_NIL, dev->otherend,
 832                         "ring-ref", "%u", &ring_ref,
 833                         "event-channel", "%u", &evtchn, NULL);
 834         if (err) {
 835                 xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
 836                 return err;
 837         }
 838
 839         return scsiback_init_sring(info, ring_ref, evtchn);
 840 }
 841
 842 /*
 843   Check for a translation entry being present
 844 */
 845 static struct v2p_entry *scsiback_chk_translation_entry(
 846         struct vscsibk_info *info, struct ids_tuple *v)
 847 {
 848         struct list_head *head = &(info->v2p_entry_lists);
 849         struct v2p_entry *entry;
 850
 851         list_for_each_entry(entry, head, l)
 852                 if ((entry->v.chn == v->chn) &&
 853                     (entry->v.tgt == v->tgt) &&
 854                     (entry->v.lun == v->lun))
 855                         return entry;
 856
 857         return NULL;
 858 }
 859
 860 /*
 861   Add a new translation entry
 862 */
 863 static int scsiback_add_translation_entry(struct vscsibk_info *info,
 864                                           char *phy, struct ids_tuple *v)
 865 {
 866         int err = 0;
 867         struct v2p_entry *new;
 868         unsigned long flags;
 869         char *lunp;
 870         unsigned long long unpacked_lun;
 871         struct se_lun *se_lun;
 872         struct scsiback_tpg *tpg_entry, *tpg = NULL;
 873         char *error = "doesn't exist";
 874
 875         lunp = strrchr(phy, ':');
 876         if (!lunp) {
 877                 pr_err("illegal format of physical device %s\n", phy);
 878                 return -EINVAL;
 879         }
 880         *lunp = 0;
 881         lunp++;
 882         err = kstrtoull(lunp, 10, &unpacked_lun);
 883         if (err < 0) {
 884                 pr_err("lun number not valid: %s\n", lunp);
 885                 return err;
 886         }
 887
 888         mutex_lock(&scsiback_mutex);
 889         list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
 890                 if (!strcmp(phy, tpg_entry->tport->tport_name) ||
 891                     !strcmp(phy, tpg_entry->param_alias)) {
 892                         mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
 893                         hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
 894                                 if (se_lun->unpacked_lun == unpacked_lun) {
 895                                         if (!tpg_entry->tpg_nexus)
 896                                                 error = "nexus undefined";
 897                                         else
 898                                                 tpg = tpg_entry;
 899                                         break;
 900                                 }
 901                         }
 902                         mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
 903                         break;
 904                 }
 905         }
 906         if (tpg) {
 907                 mutex_lock(&tpg->tv_tpg_mutex);
 908                 tpg->tv_tpg_fe_count++;
 909                 mutex_unlock(&tpg->tv_tpg_mutex);
 910         }
 911         mutex_unlock(&scsiback_mutex);
 912
 913         if (!tpg) {
 914                 pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
 915                 return -ENODEV;
 916         }
 917
 918         new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
 919         if (new == NULL) {
 920                 err = -ENOMEM;
 921                 goto out_free;
 922         }
 923
 924         spin_lock_irqsave(&info->v2p_lock, flags);
 925
 926         /* Check double assignment to identical virtual ID */
 927         if (scsiback_chk_translation_entry(info, v)) {
 928                 pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 929                 err = -EEXIST;
 930                 goto out;
 931         }
 932
 933         /* Create a new translation entry and add to the list */
 934         kref_init(&new->kref);
 935         new->v = *v;
 936         new->tpg = tpg;
 937         new->lun = unpacked_lun;
 938         list_add_tail(&new->l, &info->v2p_entry_lists);
 939
 940 out:
 941         spin_unlock_irqrestore(&info->v2p_lock, flags);
 942
 943 out_free:
 944         if (err) {
 945                 mutex_lock(&tpg->tv_tpg_mutex);
 946                 tpg->tv_tpg_fe_count--;
 947                 mutex_unlock(&tpg->tv_tpg_mutex);
 948                 kfree(new);
 949         }
 950
 951         return err;
 952 }
 953
 954 static void __scsiback_del_translation_entry(struct v2p_entry *entry)
 955 {
 956         list_del(&entry->l);
 957         kref_put(&entry->kref, scsiback_free_translation_entry);
 958 }
 959
 960 /*
 961   Delete the translation entry specified
 962 */
 963 static int scsiback_del_translation_entry(struct vscsibk_info *info,
 964                                           struct ids_tuple *v)
 965 {
 966         struct v2p_entry *entry;
 967         unsigned long flags;
 968         int ret = 0;
 969
 970         spin_lock_irqsave(&info->v2p_lock, flags);
 971         /* Find out the translation entry specified */
 972         entry = scsiback_chk_translation_entry(info, v);
 973         if (entry)
 974                 __scsiback_del_translation_entry(entry);
 975         else
 976                 ret = -ENOENT;
 977
 978         spin_unlock_irqrestore(&info->v2p_lock, flags);
 979         return ret;
 980 }
 981
 982 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
 983                                 char *phy, struct ids_tuple *vir, int try)
 984 {
 985         struct v2p_entry *entry;
 986         unsigned long flags;
 987         int err;
 988
 989         if (try) {
 990                 spin_lock_irqsave(&info->v2p_lock, flags);
 991                 entry = scsiback_chk_translation_entry(info, vir);
 992                 spin_unlock_irqrestore(&info->v2p_lock, flags);
 993                 if (entry)
 994                         return;
 995         }
 996         if (!scsiback_add_translation_entry(info, phy, vir)) {
 997                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
 998                                   "%d", XenbusStateInitialised)) {
 999                         pr_err("xenbus_printf error %s\n", state);
1000                         scsiback_del_translation_entry(info, vir);
1001                 }
1002         } else if (!try) {
1003                 err = xenbus_printf(XBT_NIL, info->dev->nodename, state,
1004                               "%d", XenbusStateClosed);
1005                 if (err)
1006                         xenbus_dev_error(info->dev, err,
1007                                 "%s: writing %s", __func__, state);
1008         }
1009 }
1010
1011 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1012                                 struct ids_tuple *vir)
1013 {
1014         if (!scsiback_del_translation_entry(info, vir)) {
1015                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1016                                   "%d", XenbusStateClosed))
1017                         pr_err("xenbus_printf error %s\n", state);
1018         }
1019 }
1020
1021 #define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1022 #define VSCSIBACK_OP_UPDATEDEV_STATE    2
1023
1024 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1025                                      char *ent)
1026 {
1027         int err;
1028         struct ids_tuple vir;
1029         char *val;
1030         int device_state;
1031         char phy[VSCSI_NAMELEN];
1032         char str[64];
1033         char state[64];
1034         struct xenbus_device *dev = info->dev;
1035
1036         /* read status */
1037         snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1038         err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1039         if (XENBUS_EXIST_ERR(err))
1040                 return;
1041
1042         /* physical SCSI device */
1043         snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1044         val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1045         if (IS_ERR(val)) {
1046                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1047                               "%d", XenbusStateClosed);
1048                 if (err)
1049                         xenbus_dev_error(info->dev, err,
1050                                 "%s: writing %s", __func__, state);
1051                 return;
1052         }
1053         strlcpy(phy, val, VSCSI_NAMELEN);
1054         kfree(val);
1055
1056         /* virtual SCSI device */
1057         snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1058         err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1059                            &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1060         if (XENBUS_EXIST_ERR(err)) {
1061                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1062                               "%d", XenbusStateClosed);
1063                 if (err)
1064                         xenbus_dev_error(info->dev, err,
1065                                 "%s: writing %s", __func__, state);
1066                 return;
1067         }
1068
1069         switch (op) {
1070         case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1071                 switch (device_state) {
1072                 case XenbusStateInitialising:
1073                         scsiback_do_add_lun(info, state, phy, &vir, 0);
1074                         break;
1075                 case XenbusStateConnected:
1076                         scsiback_do_add_lun(info, state, phy, &vir, 1);
1077                         break;
1078                 case XenbusStateClosing:
1079                         scsiback_do_del_lun(info, state, &vir);
1080                         break;
1081                 default:
1082                         break;
1083                 }
1084                 break;
1085
1086         case VSCSIBACK_OP_UPDATEDEV_STATE:
1087                 if (device_state == XenbusStateInitialised) {
1088                         /* modify vscsi-devs/dev-x/state */
1089                         if (xenbus_printf(XBT_NIL, dev->nodename, state,
1090                                           "%d", XenbusStateConnected)) {
1091                                 pr_err("xenbus_printf error %s\n", str);
1092                                 scsiback_del_translation_entry(info, &vir);
1093                                 xenbus_printf(XBT_NIL, dev->nodename, state,
1094                                               "%d", XenbusStateClosed);
1095                         }
1096                 }
1097                 break;
1098         /* When it is necessary, processing is added here. */
1099         default:
1100                 break;
1101         }
1102 }
1103
1104 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1105 {
1106         int i;
1107         char **dir;
1108         unsigned int ndir = 0;
1109
1110         dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1111                                &ndir);
1112         if (IS_ERR(dir))
1113                 return;
1114
1115         for (i = 0; i < ndir; i++)
1116                 scsiback_do_1lun_hotplug(info, op, dir[i]);
1117
1118         kfree(dir);
1119 }
1120
1121 static void scsiback_frontend_changed(struct xenbus_device *dev,
1122                                         enum xenbus_state frontend_state)
1123 {
1124         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1125
1126         switch (frontend_state) {
1127         case XenbusStateInitialising:
1128                 break;
1129
1130         case XenbusStateInitialised:
1131                 if (scsiback_map(info))
1132                         break;
1133
1134                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1135                 xenbus_switch_state(dev, XenbusStateConnected);
1136                 break;
1137
1138         case XenbusStateConnected:
1139                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1140
1141                 if (dev->state == XenbusStateConnected)
1142                         break;
1143
1144                 xenbus_switch_state(dev, XenbusStateConnected);
1145                 break;
1146
1147         case XenbusStateClosing:
1148                 if (info->irq)
1149                         scsiback_disconnect(info);
1150
1151                 xenbus_switch_state(dev, XenbusStateClosing);
1152                 break;
1153
1154         case XenbusStateClosed:
1155                 xenbus_switch_state(dev, XenbusStateClosed);
1156                 if (xenbus_dev_is_online(dev))
1157                         break;
1158                 fallthrough;    /* if not online */
1159         case XenbusStateUnknown:
1160                 device_unregister(&dev->dev);
1161                 break;
1162
1163         case XenbusStateReconfiguring:
1164                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1165                 xenbus_switch_state(dev, XenbusStateReconfigured);
1166
1167                 break;
1168
1169         default:
1170                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1171                                         frontend_state);
1172                 break;
1173         }
1174 }
1175
1176 /*
1177   Release the translation entry specfied
1178 */
1179 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1180 {
1181         struct v2p_entry *entry, *tmp;
1182         struct list_head *head = &(info->v2p_entry_lists);
1183         unsigned long flags;
1184
1185         spin_lock_irqsave(&info->v2p_lock, flags);
1186
1187         list_for_each_entry_safe(entry, tmp, head, l)
1188                 __scsiback_del_translation_entry(entry);
1189
1190         spin_unlock_irqrestore(&info->v2p_lock, flags);
1191 }
1192
1193 static int scsiback_remove(struct xenbus_device *dev)
1194 {
1195         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1196
1197         if (info->irq)
1198                 scsiback_disconnect(info);
1199
1200         scsiback_release_translation_entry(info);
1201
1202         gnttab_page_cache_shrink(&info->free_pages, 0);
1203
1204         dev_set_drvdata(&dev->dev, NULL);
1205
1206         return 0;
1207 }
1208
1209 static int scsiback_probe(struct xenbus_device *dev,
1210                            const struct xenbus_device_id *id)
1211 {
1212         int err;
1213
1214         struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1215                                             GFP_KERNEL);
1216
1217         pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1218
1219         if (!info) {
1220                 xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1221                 return -ENOMEM;
1222         }
1223         info->dev = dev;
1224         dev_set_drvdata(&dev->dev, info);
1225
1226         info->domid = dev->otherend_id;
1227         spin_lock_init(&info->ring_lock);
1228         atomic_set(&info->nr_unreplied_reqs, 0);
1229         init_waitqueue_head(&info->waiting_to_free);
1230         info->dev = dev;
1231         info->irq = 0;
1232         INIT_LIST_HEAD(&info->v2p_entry_lists);
1233         spin_lock_init(&info->v2p_lock);
1234         gnttab_page_cache_init(&info->free_pages);
1235
1236         err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1237                             SG_ALL);
1238         if (err)
1239                 xenbus_dev_error(dev, err, "writing feature-sg-grant");
1240
1241         err = xenbus_switch_state(dev, XenbusStateInitWait);
1242         if (err)
1243                 goto fail;
1244
1245         return 0;
1246
1247 fail:
1248         pr_warn("%s failed\n", __func__);
1249         scsiback_remove(dev);
1250
1251         return err;
1252 }
1253
1254 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1255 {
1256         switch (tport->tport_proto_id) {
1257         case SCSI_PROTOCOL_SAS:
1258                 return "SAS";
1259         case SCSI_PROTOCOL_FCP:
1260                 return "FCP";
1261         case SCSI_PROTOCOL_ISCSI:
1262                 return "iSCSI";
1263         default:
1264                 break;
1265         }
1266
1267         return "Unknown";
1268 }
1269
1270 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1271 {
1272         struct scsiback_tpg *tpg = container_of(se_tpg,
1273                                 struct scsiback_tpg, se_tpg);
1274         struct scsiback_tport *tport = tpg->tport;
1275
1276         return &tport->tport_name[0];
1277 }
1278
1279 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1280 {
1281         struct scsiback_tpg *tpg = container_of(se_tpg,
1282                                 struct scsiback_tpg, se_tpg);
1283         return tpg->tport_tpgt;
1284 }
1285
1286 static struct se_wwn *
1287 scsiback_make_tport(struct target_fabric_configfs *tf,
1288                      struct config_group *group,
1289                      const char *name)
1290 {
1291         struct scsiback_tport *tport;
1292         char *ptr;
1293         u64 wwpn = 0;
1294         int off = 0;
1295
1296         tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1297         if (!tport)
1298                 return ERR_PTR(-ENOMEM);
1299
1300         tport->tport_wwpn = wwpn;
1301         /*
1302          * Determine the emulated Protocol Identifier and Target Port Name
1303          * based on the incoming configfs directory name.
1304          */
1305         ptr = strstr(name, "naa.");
1306         if (ptr) {
1307                 tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1308                 goto check_len;
1309         }
1310         ptr = strstr(name, "fc.");
1311         if (ptr) {
1312                 tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1313                 off = 3; /* Skip over "fc." */
1314                 goto check_len;
1315         }
1316         ptr = strstr(name, "iqn.");
1317         if (ptr) {
1318                 tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1319                 goto check_len;
1320         }
1321
1322         pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1323         kfree(tport);
1324         return ERR_PTR(-EINVAL);
1325
1326 check_len:
1327         if (strlen(name) >= VSCSI_NAMELEN) {
1328                 pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1329                         scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1330                 kfree(tport);
1331                 return ERR_PTR(-EINVAL);
1332         }
1333         snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1334
1335         pr_debug("Allocated emulated Target %s Address: %s\n",
1336                  scsiback_dump_proto_id(tport), name);
1337
1338         return &tport->tport_wwn;
1339 }
1340
1341 static void scsiback_drop_tport(struct se_wwn *wwn)
1342 {
1343         struct scsiback_tport *tport = container_of(wwn,
1344                                 struct scsiback_tport, tport_wwn);
1345
1346         pr_debug("Deallocating emulated Target %s Address: %s\n",
1347                  scsiback_dump_proto_id(tport), tport->tport_name);
1348
1349         kfree(tport);
1350 }
1351
1352 static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1353 {
1354         return 1;
1355 }
1356
1357 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1358 {
1359         return transport_generic_free_cmd(se_cmd, 0);
1360 }
1361
1362 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1363 {
1364         target_free_tag(se_cmd->se_sess, se_cmd);
1365 }
1366
1367 static u32 scsiback_sess_get_index(struct se_session *se_sess)
1368 {
1369         return 0;
1370 }
1371
1372 static int scsiback_write_pending(struct se_cmd *se_cmd)
1373 {
1374         /* Go ahead and process the write immediately */
1375         target_execute_cmd(se_cmd);
1376
1377         return 0;
1378 }
1379
1380 static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1381 {
1382 }
1383
1384 static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1385 {
1386         return 0;
1387 }
1388
1389 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1390 {
1391         struct vscsibk_pend *pending_req = container_of(se_cmd,
1392                                 struct vscsibk_pend, se_cmd);
1393
1394         pending_req->result = SAM_STAT_GOOD;
1395         scsiback_cmd_done(pending_req);
1396         return 0;
1397 }
1398
1399 static int scsiback_queue_status(struct se_cmd *se_cmd)
1400 {
1401         struct vscsibk_pend *pending_req = container_of(se_cmd,
1402                                 struct vscsibk_pend, se_cmd);
1403
1404         if (se_cmd->sense_buffer &&
1405             ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1406              (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1407                 pending_req->result = (DRIVER_SENSE << 24) |
1408                                       SAM_STAT_CHECK_CONDITION;
1409         else
1410                 pending_req->result = se_cmd->scsi_status;
1411
1412         scsiback_cmd_done(pending_req);
1413         return 0;
1414 }
1415
1416 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1417 {
1418         struct vscsibk_pend *pending_req = container_of(se_cmd,
1419                                 struct vscsibk_pend, se_cmd);
1420
1421         complete(&pending_req->tmr_done);
1422 }
1423
1424 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1425 {
1426 }
1427
1428 static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1429                                              char *page)
1430 {
1431         struct se_portal_group *se_tpg = param_to_tpg(item);
1432         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1433                                                 se_tpg);
1434         ssize_t rb;
1435
1436         mutex_lock(&tpg->tv_tpg_mutex);
1437         rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1438         mutex_unlock(&tpg->tv_tpg_mutex);
1439
1440         return rb;
1441 }
1442
1443 static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1444                                               const char *page, size_t count)
1445 {
1446         struct se_portal_group *se_tpg = param_to_tpg(item);
1447         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1448                                                 se_tpg);
1449         int len;
1450
1451         if (strlen(page) >= VSCSI_NAMELEN) {
1452                 pr_err("param alias: %s, exceeds max: %d\n", page,
1453                         VSCSI_NAMELEN);
1454                 return -EINVAL;
1455         }
1456
1457         mutex_lock(&tpg->tv_tpg_mutex);
1458         len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1459         if (tpg->param_alias[len - 1] == '\n')
1460                 tpg->param_alias[len - 1] = '\0';
1461         mutex_unlock(&tpg->tv_tpg_mutex);
1462
1463         return count;
1464 }
1465
1466 CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1467
1468 static struct configfs_attribute *scsiback_param_attrs[] = {
1469         &scsiback_tpg_param_attr_alias,
1470         NULL,
1471 };
1472
1473 static int scsiback_alloc_sess_cb(struct se_portal_group *se_tpg,
1474                                   struct se_session *se_sess, void *p)
1475 {
1476         struct scsiback_tpg *tpg = container_of(se_tpg,
1477                                 struct scsiback_tpg, se_tpg);
1478
1479         tpg->tpg_nexus = p;
1480         return 0;
1481 }
1482
1483 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1484                                 const char *name)
1485 {
1486         struct scsiback_nexus *tv_nexus;
1487         int ret = 0;
1488
1489         mutex_lock(&tpg->tv_tpg_mutex);
1490         if (tpg->tpg_nexus) {
1491                 pr_debug("tpg->tpg_nexus already exists\n");
1492                 ret = -EEXIST;
1493                 goto out_unlock;
1494         }
1495
1496         tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1497         if (!tv_nexus) {
1498                 ret = -ENOMEM;
1499                 goto out_unlock;
1500         }
1501
1502         tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg,
1503                                                      VSCSI_DEFAULT_SESSION_TAGS,
1504                                                      sizeof(struct vscsibk_pend),
1505                                                      TARGET_PROT_NORMAL, name,
1506                                                      tv_nexus, scsiback_alloc_sess_cb);
1507         if (IS_ERR(tv_nexus->tvn_se_sess)) {
1508                 kfree(tv_nexus);
1509                 ret = -ENOMEM;
1510                 goto out_unlock;
1511         }
1512
1513 out_unlock:
1514         mutex_unlock(&tpg->tv_tpg_mutex);
1515         return ret;
1516 }
1517
1518 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1519 {
1520         struct se_session *se_sess;
1521         struct scsiback_nexus *tv_nexus;
1522
1523         mutex_lock(&tpg->tv_tpg_mutex);
1524         tv_nexus = tpg->tpg_nexus;
1525         if (!tv_nexus) {
1526                 mutex_unlock(&tpg->tv_tpg_mutex);
1527                 return -ENODEV;
1528         }
1529
1530         se_sess = tv_nexus->tvn_se_sess;
1531         if (!se_sess) {
1532                 mutex_unlock(&tpg->tv_tpg_mutex);
1533                 return -ENODEV;
1534         }
1535
1536         if (tpg->tv_tpg_port_count != 0) {
1537                 mutex_unlock(&tpg->tv_tpg_mutex);
1538                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1539                         tpg->tv_tpg_port_count);
1540                 return -EBUSY;
1541         }
1542
1543         if (tpg->tv_tpg_fe_count != 0) {
1544                 mutex_unlock(&tpg->tv_tpg_mutex);
1545                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1546                         tpg->tv_tpg_fe_count);
1547                 return -EBUSY;
1548         }
1549
1550         pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1551                 scsiback_dump_proto_id(tpg->tport),
1552                 tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1553
1554         /*
1555          * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1556          */
1557         target_remove_session(se_sess);
1558         tpg->tpg_nexus = NULL;
1559         mutex_unlock(&tpg->tv_tpg_mutex);
1560
1561         kfree(tv_nexus);
1562         return 0;
1563 }
1564
1565 static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1566 {
1567         struct se_portal_group *se_tpg = to_tpg(item);
1568         struct scsiback_tpg *tpg = container_of(se_tpg,
1569                                 struct scsiback_tpg, se_tpg);
1570         struct scsiback_nexus *tv_nexus;
1571         ssize_t ret;
1572
1573         mutex_lock(&tpg->tv_tpg_mutex);
1574         tv_nexus = tpg->tpg_nexus;
1575         if (!tv_nexus) {
1576                 mutex_unlock(&tpg->tv_tpg_mutex);
1577                 return -ENODEV;
1578         }
1579         ret = snprintf(page, PAGE_SIZE, "%s\n",
1580                         tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1581         mutex_unlock(&tpg->tv_tpg_mutex);
1582
1583         return ret;
1584 }
1585
1586 static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
1587                 const char *page, size_t count)
1588 {
1589         struct se_portal_group *se_tpg = to_tpg(item);
1590         struct scsiback_tpg *tpg = container_of(se_tpg,
1591                                 struct scsiback_tpg, se_tpg);
1592         struct scsiback_tport *tport_wwn = tpg->tport;
1593         unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1594         int ret;
1595         /*
1596          * Shutdown the active I_T nexus if 'NULL' is passed.
1597          */
1598         if (!strncmp(page, "NULL", 4)) {
1599                 ret = scsiback_drop_nexus(tpg);
1600                 return (!ret) ? count : ret;
1601         }
1602         /*
1603          * Otherwise make sure the passed virtual Initiator port WWN matches
1604          * the fabric protocol_id set in scsiback_make_tport(), and call
1605          * scsiback_make_nexus().
1606          */
1607         if (strlen(page) >= VSCSI_NAMELEN) {
1608                 pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1609                         page, VSCSI_NAMELEN);
1610                 return -EINVAL;
1611         }
1612         snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1613
1614         ptr = strstr(i_port, "naa.");
1615         if (ptr) {
1616                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1617                         pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1618                                 i_port, scsiback_dump_proto_id(tport_wwn));
1619                         return -EINVAL;
1620                 }
1621                 port_ptr = &i_port[0];
1622                 goto check_newline;
1623         }
1624         ptr = strstr(i_port, "fc.");
1625         if (ptr) {
1626                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1627                         pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1628                                 i_port, scsiback_dump_proto_id(tport_wwn));
1629                         return -EINVAL;
1630                 }
1631                 port_ptr = &i_port[3]; /* Skip over "fc." */
1632                 goto check_newline;
1633         }
1634         ptr = strstr(i_port, "iqn.");
1635         if (ptr) {
1636                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1637                         pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1638                                 i_port, scsiback_dump_proto_id(tport_wwn));
1639                         return -EINVAL;
1640                 }
1641                 port_ptr = &i_port[0];
1642                 goto check_newline;
1643         }
1644         pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1645                 i_port);
1646         return -EINVAL;
1647         /*
1648          * Clear any trailing newline for the NAA WWN
1649          */
1650 check_newline:
1651         if (i_port[strlen(i_port) - 1] == '\n')
1652                 i_port[strlen(i_port) - 1] = '\0';
1653
1654         ret = scsiback_make_nexus(tpg, port_ptr);
1655         if (ret < 0)
1656                 return ret;
1657
1658         return count;
1659 }
1660
1661 CONFIGFS_ATTR(scsiback_tpg_, nexus);
1662
1663 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1664         &scsiback_tpg_attr_nexus,
1665         NULL,
1666 };
1667
1668 static ssize_t
1669 scsiback_wwn_version_show(struct config_item *item, char *page)
1670 {
1671         return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1672                 UTS_RELEASE"\n",
1673                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1674 }
1675
1676 CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1677
1678 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1679         &scsiback_wwn_attr_version,
1680         NULL,
1681 };
1682
1683 static int scsiback_port_link(struct se_portal_group *se_tpg,
1684                                struct se_lun *lun)
1685 {
1686         struct scsiback_tpg *tpg = container_of(se_tpg,
1687                                 struct scsiback_tpg, se_tpg);
1688
1689         mutex_lock(&tpg->tv_tpg_mutex);
1690         tpg->tv_tpg_port_count++;
1691         mutex_unlock(&tpg->tv_tpg_mutex);
1692
1693         return 0;
1694 }
1695
1696 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1697                                   struct se_lun *lun)
1698 {
1699         struct scsiback_tpg *tpg = container_of(se_tpg,
1700                                 struct scsiback_tpg, se_tpg);
1701
1702         mutex_lock(&tpg->tv_tpg_mutex);
1703         tpg->tv_tpg_port_count--;
1704         mutex_unlock(&tpg->tv_tpg_mutex);
1705 }
1706
1707 static struct se_portal_group *
1708 scsiback_make_tpg(struct se_wwn *wwn, const char *name)
1709 {
1710         struct scsiback_tport *tport = container_of(wwn,
1711                         struct scsiback_tport, tport_wwn);
1712
1713         struct scsiback_tpg *tpg;
1714         u16 tpgt;
1715         int ret;
1716
1717         if (strstr(name, "tpgt_") != name)
1718                 return ERR_PTR(-EINVAL);
1719         ret = kstrtou16(name + 5, 10, &tpgt);
1720         if (ret)
1721                 return ERR_PTR(ret);
1722
1723         tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1724         if (!tpg)
1725                 return ERR_PTR(-ENOMEM);
1726
1727         mutex_init(&tpg->tv_tpg_mutex);
1728         INIT_LIST_HEAD(&tpg->tv_tpg_list);
1729         INIT_LIST_HEAD(&tpg->info_list);
1730         tpg->tport = tport;
1731         tpg->tport_tpgt = tpgt;
1732
1733         ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1734         if (ret < 0) {
1735                 kfree(tpg);
1736                 return NULL;
1737         }
1738         mutex_lock(&scsiback_mutex);
1739         list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1740         mutex_unlock(&scsiback_mutex);
1741
1742         return &tpg->se_tpg;
1743 }
1744
1745 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1746 {
1747         struct scsiback_tpg *tpg = container_of(se_tpg,
1748                                 struct scsiback_tpg, se_tpg);
1749
1750         mutex_lock(&scsiback_mutex);
1751         list_del(&tpg->tv_tpg_list);
1752         mutex_unlock(&scsiback_mutex);
1753         /*
1754          * Release the virtual I_T Nexus for this xen-pvscsi TPG
1755          */
1756         scsiback_drop_nexus(tpg);
1757         /*
1758          * Deregister the se_tpg from TCM.
1759          */
1760         core_tpg_deregister(se_tpg);
1761         kfree(tpg);
1762 }
1763
1764 static int scsiback_check_true(struct se_portal_group *se_tpg)
1765 {
1766         return 1;
1767 }
1768
1769 static int scsiback_check_false(struct se_portal_group *se_tpg)
1770 {
1771         return 0;
1772 }
1773
1774 static const struct target_core_fabric_ops scsiback_ops = {
1775         .module                         = THIS_MODULE,
1776         .fabric_name                    = "xen-pvscsi",
1777         .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1778         .tpg_get_tag                    = scsiback_get_tag,
1779         .tpg_check_demo_mode            = scsiback_check_true,
1780         .tpg_check_demo_mode_cache      = scsiback_check_true,
1781         .tpg_check_demo_mode_write_protect = scsiback_check_false,
1782         .tpg_check_prod_mode_write_protect = scsiback_check_false,
1783         .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1784         .check_stop_free                = scsiback_check_stop_free,
1785         .release_cmd                    = scsiback_release_cmd,
1786         .sess_get_index                 = scsiback_sess_get_index,
1787         .sess_get_initiator_sid         = NULL,
1788         .write_pending                  = scsiback_write_pending,
1789         .set_default_node_attributes    = scsiback_set_default_node_attrs,
1790         .get_cmd_state                  = scsiback_get_cmd_state,
1791         .queue_data_in                  = scsiback_queue_data_in,
1792         .queue_status                   = scsiback_queue_status,
1793         .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1794         .aborted_task                   = scsiback_aborted_task,
1795         /*
1796          * Setup callers for generic logic in target_core_fabric_configfs.c
1797          */
1798         .fabric_make_wwn                = scsiback_make_tport,
1799         .fabric_drop_wwn                = scsiback_drop_tport,
1800         .fabric_make_tpg                = scsiback_make_tpg,
1801         .fabric_drop_tpg                = scsiback_drop_tpg,
1802         .fabric_post_link               = scsiback_port_link,
1803         .fabric_pre_unlink              = scsiback_port_unlink,
1804
1805         .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1806         .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1807         .tfc_tpg_param_attrs            = scsiback_param_attrs,
1808 };
1809
1810 static const struct xenbus_device_id scsiback_ids[] = {
1811         { "vscsi" },
1812         { "" }
1813 };
1814
1815 static struct xenbus_driver scsiback_driver = {
1816         .ids                    = scsiback_ids,
1817         .probe                  = scsiback_probe,
1818         .remove                 = scsiback_remove,
1819         .otherend_changed       = scsiback_frontend_changed
1820 };
1821
1822 static int __init scsiback_init(void)
1823 {
1824         int ret;
1825
1826         if (!xen_domain())
1827                 return -ENODEV;
1828
1829         pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1830                  VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1831
1832         ret = xenbus_register_backend(&scsiback_driver);
1833         if (ret)
1834                 goto out;
1835
1836         ret = target_register_template(&scsiback_ops);
1837         if (ret)
1838                 goto out_unregister_xenbus;
1839
1840         return 0;
1841
1842 out_unregister_xenbus:
1843         xenbus_unregister_driver(&scsiback_driver);
1844 out:
1845         pr_err("%s: error %d\n", __func__, ret);
1846         return ret;
1847 }
1848
1849 static void __exit scsiback_exit(void)
1850 {
1851         target_unregister_template(&scsiback_ops);
1852         xenbus_unregister_driver(&scsiback_driver);
1853 }
1854
1855 module_init(scsiback_init);
1856 module_exit(scsiback_exit);
1857
1858 MODULE_DESCRIPTION("Xen SCSI backend driver");
1859 MODULE_LICENSE("Dual BSD/GPL");
1860 MODULE_ALIAS("xen-backend:vscsi");
1861 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");