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