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 <linux/module.h>
  37 #include <linux/utsname.h>
  38 #include <linux/interrupt.h>
  39 #include <linux/slab.h>
  40 #include <linux/wait.h>
  41 #include <linux/sched.h>
  42 #include <linux/list.h>
  43 #include <linux/gfp.h>
  44 #include <linux/delay.h>
  45 #include <linux/spinlock.h>
  46 #include <linux/configfs.h>
  47
  48 #include <generated/utsrelease.h>
  49
  50 #include <scsi/scsi_host.h> /* SG_ALL */
  51
  52 #include <target/target_core_base.h>
  53 #include <target/target_core_fabric.h>
  54
  55 #include <asm/hypervisor.h>
  56
  57 #include <xen/xen.h>
  58 #include <xen/balloon.h>
  59 #include <xen/events.h>
  60 #include <xen/xenbus.h>
  61 #include <xen/grant_table.h>
  62 #include <xen/page.h>
  63
  64 #include <xen/interface/grant_table.h>
  65 #include <xen/interface/io/vscsiif.h>
  66
  67 #define VSCSI_VERSION   "v0.1"
  68 #define VSCSI_NAMELEN   32
  69
  70 struct ids_tuple {
  71         unsigned int hst;               /* host    */
  72         unsigned int chn;               /* channel */
  73         unsigned int tgt;               /* target  */
  74         unsigned int lun;               /* LUN     */
  75 };
  76
  77 struct v2p_entry {
  78         struct ids_tuple v;             /* translate from */
  79         struct scsiback_tpg *tpg;       /* translate to   */
  80         unsigned int lun;
  81         struct kref kref;
  82         struct list_head l;
  83 };
  84
  85 struct vscsibk_info {
  86         struct xenbus_device *dev;
  87
  88         domid_t domid;
  89         unsigned int irq;
  90
  91         struct vscsiif_back_ring ring;
  92
  93         spinlock_t ring_lock;
  94         atomic_t nr_unreplied_reqs;
  95
  96         spinlock_t v2p_lock;
  97         struct list_head v2p_entry_lists;
  98
  99         wait_queue_head_t waiting_to_free;
 100
 101         struct gnttab_page_cache free_pages;
 102 };
 103
 104 /* theoretical maximum of grants for one request */
 105 #define VSCSI_MAX_GRANTS        (SG_ALL + VSCSIIF_SG_TABLESIZE)
 106
 107 /*
 108  * VSCSI_GRANT_BATCH is the maximum number of grants to be processed in one
 109  * call to map/unmap grants. Don't choose it too large, as there are arrays
 110  * with VSCSI_GRANT_BATCH elements allocated on the stack.
 111  */
 112 #define VSCSI_GRANT_BATCH       16
 113
 114 struct vscsibk_pend {
 115         uint16_t rqid;
 116
 117         uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE];
 118         uint8_t cmd_len;
 119
 120         uint8_t sc_data_direction;
 121         uint16_t n_sg;          /* real length of SG list */
 122         uint16_t n_grants;      /* SG pages and potentially SG list */
 123         uint32_t data_len;
 124         uint32_t result;
 125
 126         struct vscsibk_info *info;
 127         struct v2p_entry *v2p;
 128         struct scatterlist *sgl;
 129
 130         uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];
 131
 132         grant_handle_t grant_handles[VSCSI_MAX_GRANTS];
 133         struct page *pages[VSCSI_MAX_GRANTS];
 134
 135         struct se_cmd se_cmd;
 136
 137         struct completion tmr_done;
 138 };
 139
 140 #define VSCSI_DEFAULT_SESSION_TAGS      128
 141
 142 struct scsiback_nexus {
 143         /* Pointer to TCM session for I_T Nexus */
 144         struct se_session *tvn_se_sess;
 145 };
 146
 147 struct scsiback_tport {
 148         /* SCSI protocol the tport is providing */
 149         u8 tport_proto_id;
 150         /* Binary World Wide unique Port Name for pvscsi Target port */
 151         u64 tport_wwpn;
 152         /* ASCII formatted WWPN for pvscsi Target port */
 153         char tport_name[VSCSI_NAMELEN];
 154         /* Returned by scsiback_make_tport() */
 155         struct se_wwn tport_wwn;
 156 };
 157
 158 struct scsiback_tpg {
 159         /* scsiback port target portal group tag for TCM */
 160         u16 tport_tpgt;
 161         /* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
 162         int tv_tpg_port_count;
 163         /* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
 164         int tv_tpg_fe_count;
 165         /* list for scsiback_list */
 166         struct list_head tv_tpg_list;
 167         /* Used to protect access for tpg_nexus */
 168         struct mutex tv_tpg_mutex;
 169         /* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
 170         struct scsiback_nexus *tpg_nexus;
 171         /* Pointer back to scsiback_tport */
 172         struct scsiback_tport *tport;
 173         /* Returned by scsiback_make_tpg() */
 174         struct se_portal_group se_tpg;
 175         /* alias used in xenstore */
 176         char param_alias[VSCSI_NAMELEN];
 177         /* list of info structures related to this target portal group */
 178         struct list_head info_list;
 179 };
 180
 181 #define SCSIBACK_INVALID_HANDLE (~0)
 182
 183 static bool log_print_stat;
 184 module_param(log_print_stat, bool, 0644);
 185
 186 static int scsiback_max_buffer_pages = 1024;
 187 module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
 188 MODULE_PARM_DESC(max_buffer_pages,
 189 "Maximum number of free pages to keep in backend buffer");
 190
 191 /* Global spinlock to protect scsiback TPG list */
 192 static DEFINE_MUTEX(scsiback_mutex);
 193 static LIST_HEAD(scsiback_list);
 194
 195 static void scsiback_get(struct vscsibk_info *info)
 196 {
 197         atomic_inc(&info->nr_unreplied_reqs);
 198 }
 199
 200 static void scsiback_put(struct vscsibk_info *info)
 201 {
 202         if (atomic_dec_and_test(&info->nr_unreplied_reqs))
 203                 wake_up(&info->waiting_to_free);
 204 }
 205
 206 static unsigned long vaddr_page(struct page *page)
 207 {
 208         unsigned long pfn = page_to_pfn(page);
 209
 210         return (unsigned long)pfn_to_kaddr(pfn);
 211 }
 212
 213 static unsigned long vaddr(struct vscsibk_pend *req, int seg)
 214 {
 215         return vaddr_page(req->pages[seg]);
 216 }
 217
 218 static void scsiback_print_status(char *sense_buffer, int errors,
 219                                         struct vscsibk_pend *pending_req)
 220 {
 221         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 222
 223         pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x\n",
 224                tpg->tport->tport_name, pending_req->v2p->lun,
 225                pending_req->cmnd[0], errors & 0xff, COMMAND_COMPLETE,
 226                host_byte(errors));
 227 }
 228
 229 static void scsiback_fast_flush_area(struct vscsibk_pend *req)
 230 {
 231         struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
 232         struct page *pages[VSCSI_GRANT_BATCH];
 233         unsigned int i, invcount = 0;
 234         grant_handle_t handle;
 235         int err;
 236
 237         kfree(req->sgl);
 238         req->sgl = NULL;
 239         req->n_sg = 0;
 240
 241         if (!req->n_grants)
 242                 return;
 243
 244         for (i = 0; i < req->n_grants; i++) {
 245                 handle = req->grant_handles[i];
 246                 if (handle == SCSIBACK_INVALID_HANDLE)
 247                         continue;
 248                 gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
 249                                     GNTMAP_host_map, handle);
 250                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 251                 pages[invcount] = req->pages[i];
 252                 put_page(pages[invcount]);
 253                 invcount++;
 254                 if (invcount < VSCSI_GRANT_BATCH)
 255                         continue;
 256                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 257                 BUG_ON(err);
 258                 invcount = 0;
 259         }
 260
 261         if (invcount) {
 262                 err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 263                 BUG_ON(err);
 264         }
 265
 266         gnttab_page_cache_put(&req->info->free_pages, req->pages,
 267                               req->n_grants);
 268         req->n_grants = 0;
 269 }
 270
 271 static void scsiback_free_translation_entry(struct kref *kref)
 272 {
 273         struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
 274         struct scsiback_tpg *tpg = entry->tpg;
 275
 276         mutex_lock(&tpg->tv_tpg_mutex);
 277         tpg->tv_tpg_fe_count--;
 278         mutex_unlock(&tpg->tv_tpg_mutex);
 279
 280         kfree(entry);
 281 }
 282
 283 static void scsiback_send_response(struct vscsibk_info *info,
 284                         char *sense_buffer, int32_t result, uint32_t resid,
 285                         uint16_t rqid)
 286 {
 287         struct vscsiif_response *ring_res;
 288         int notify;
 289         struct scsi_sense_hdr sshdr;
 290         unsigned long flags;
 291         unsigned len;
 292
 293         spin_lock_irqsave(&info->ring_lock, flags);
 294
 295         ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
 296         info->ring.rsp_prod_pvt++;
 297
 298         ring_res->rslt   = result;
 299         ring_res->rqid   = rqid;
 300
 301         if (sense_buffer != NULL &&
 302             scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
 303                                  &sshdr)) {
 304                 len = min_t(unsigned, 8 + sense_buffer[7],
 305                             VSCSIIF_SENSE_BUFFERSIZE);
 306                 memcpy(ring_res->sense_buffer, sense_buffer, len);
 307                 ring_res->sense_len = len;
 308         } else {
 309                 ring_res->sense_len = 0;
 310         }
 311
 312         ring_res->residual_len = resid;
 313
 314         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
 315         spin_unlock_irqrestore(&info->ring_lock, flags);
 316
 317         if (notify)
 318                 notify_remote_via_irq(info->irq);
 319 }
 320
 321 static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
 322                         uint32_t resid, struct vscsibk_pend *pending_req)
 323 {
 324         scsiback_send_response(pending_req->info, sense_buffer, result,
 325                                resid, pending_req->rqid);
 326
 327         if (pending_req->v2p)
 328                 kref_put(&pending_req->v2p->kref,
 329                          scsiback_free_translation_entry);
 330 }
 331
 332 static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
 333 {
 334         struct vscsibk_info *info = pending_req->info;
 335         unsigned char *sense_buffer;
 336         unsigned int resid;
 337         int errors;
 338
 339         sense_buffer = pending_req->sense_buffer;
 340         resid        = pending_req->se_cmd.residual_count;
 341         errors       = pending_req->result;
 342
 343         if (errors && log_print_stat)
 344                 scsiback_print_status(sense_buffer, errors, pending_req);
 345
 346         scsiback_fast_flush_area(pending_req);
 347         scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
 348         scsiback_put(info);
 349         /*
 350          * Drop the extra KREF_ACK reference taken by target_submit_cmd_map_sgls()
 351          * ahead of scsiback_check_stop_free() ->  transport_generic_free_cmd()
 352          * final se_cmd->cmd_kref put.
 353          */
 354         target_put_sess_cmd(&pending_req->se_cmd);
 355 }
 356
 357 static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
 358 {
 359         struct se_cmd *se_cmd = &pending_req->se_cmd;
 360         struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
 361
 362         scsiback_get(pending_req->info);
 363         se_cmd->tag = pending_req->rqid;
 364         target_init_cmd(se_cmd, sess, pending_req->sense_buffer,
 365                         pending_req->v2p->lun, pending_req->data_len, 0,
 366                         pending_req->sc_data_direction, TARGET_SCF_ACK_KREF);
 367
 368         if (target_submit_prep(se_cmd, pending_req->cmnd, pending_req->sgl,
 369                                pending_req->n_sg, NULL, 0, NULL, 0, GFP_KERNEL))
 370                 return;
 371
 372         target_submit(se_cmd);
 373 }
 374
 375 static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 376         struct page **pg, grant_handle_t *grant, int cnt)
 377 {
 378         int err, i;
 379
 380         if (!cnt)
 381                 return 0;
 382
 383         err = gnttab_map_refs(map, NULL, pg, cnt);
 384         for (i = 0; i < cnt; i++) {
 385                 if (unlikely(map[i].status != GNTST_okay)) {
 386                         pr_err("invalid buffer -- could not remap it\n");
 387                         map[i].handle = SCSIBACK_INVALID_HANDLE;
 388                         if (!err)
 389                                 err = -ENOMEM;
 390                 } else {
 391                         get_page(pg[i]);
 392                 }
 393                 grant[i] = map[i].handle;
 394         }
 395         return err;
 396 }
 397
 398 static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
 399                         struct scsiif_request_segment *seg, struct page **pg,
 400                         grant_handle_t *grant, int cnt, u32 flags)
 401 {
 402         int mapcount = 0, i, err = 0;
 403         struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
 404         struct vscsibk_info *info = pending_req->info;
 405
 406         for (i = 0; i < cnt; i++) {
 407                 if (gnttab_page_cache_get(&info->free_pages, pg + mapcount)) {
 408                         gnttab_page_cache_put(&info->free_pages, pg, mapcount);
 409                         pr_err("no grant page\n");
 410                         return -ENOMEM;
 411                 }
 412                 gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
 413                                   flags, seg[i].gref, info->domid);
 414                 mapcount++;
 415                 if (mapcount < VSCSI_GRANT_BATCH)
 416                         continue;
 417                 err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 418                 pg += mapcount;
 419                 grant += mapcount;
 420                 pending_req->n_grants += mapcount;
 421                 if (err)
 422                         return err;
 423                 mapcount = 0;
 424         }
 425         err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 426         pending_req->n_grants += mapcount;
 427         return err;
 428 }
 429
 430 static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 431                                         struct vscsibk_pend *pending_req)
 432 {
 433         u32 flags;
 434         int i, err, n_segs, i_seg = 0;
 435         struct page **pg;
 436         struct scsiif_request_segment *seg;
 437         unsigned long end_seg = 0;
 438         unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
 439         unsigned int nr_sgl = 0;
 440         struct scatterlist *sg;
 441         grant_handle_t *grant;
 442
 443         pending_req->n_sg = 0;
 444         pending_req->n_grants = 0;
 445         pending_req->data_len = 0;
 446
 447         nr_segments &= ~VSCSIIF_SG_GRANT;
 448         if (!nr_segments)
 449                 return 0;
 450
 451         if (nr_segments > VSCSIIF_SG_TABLESIZE) {
 452                 pr_debug("invalid parameter nr_seg = %d\n",
 453                         ring_req->nr_segments);
 454                 return -EINVAL;
 455         }
 456
 457         if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
 458                 err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
 459                         pending_req->pages, pending_req->grant_handles,
 460                         nr_segments, GNTMAP_host_map | GNTMAP_readonly);
 461                 if (err)
 462                         return err;
 463                 nr_sgl = nr_segments;
 464                 nr_segments = 0;
 465                 for (i = 0; i < nr_sgl; i++) {
 466                         n_segs = ring_req->seg[i].length /
 467                                  sizeof(struct scsiif_request_segment);
 468                         if ((unsigned)ring_req->seg[i].offset +
 469                             (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
 470                             n_segs * sizeof(struct scsiif_request_segment) !=
 471                             ring_req->seg[i].length)
 472                                 return -EINVAL;
 473                         nr_segments += n_segs;
 474                 }
 475                 if (nr_segments > SG_ALL) {
 476                         pr_debug("invalid nr_seg = %d\n", nr_segments);
 477                         return -EINVAL;
 478                 }
 479         }
 480
 481         /* free of (sgl) in fast_flush_area() */
 482         pending_req->sgl = kmalloc_array(nr_segments,
 483                                         sizeof(struct scatterlist), GFP_KERNEL);
 484         if (!pending_req->sgl)
 485                 return -ENOMEM;
 486
 487         sg_init_table(pending_req->sgl, nr_segments);
 488         pending_req->n_sg = nr_segments;
 489
 490         flags = GNTMAP_host_map;
 491         if (pending_req->sc_data_direction == DMA_TO_DEVICE)
 492                 flags |= GNTMAP_readonly;
 493
 494         pg = pending_req->pages + nr_sgl;
 495         grant = pending_req->grant_handles + nr_sgl;
 496         if (!nr_sgl) {
 497                 seg = ring_req->seg;
 498                 err = scsiback_gnttab_data_map_list(pending_req, seg,
 499                         pg, grant, nr_segments, flags);
 500                 if (err)
 501                         return err;
 502         } else {
 503                 for (i = 0; i < nr_sgl; i++) {
 504                         seg = (struct scsiif_request_segment *)(
 505                               vaddr(pending_req, i) + ring_req->seg[i].offset);
 506                         n_segs = ring_req->seg[i].length /
 507                                  sizeof(struct scsiif_request_segment);
 508                         err = scsiback_gnttab_data_map_list(pending_req, seg,
 509                                 pg, grant, n_segs, flags);
 510                         if (err)
 511                                 return err;
 512                         pg += n_segs;
 513                         grant += n_segs;
 514                 }
 515                 end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
 516                 seg = (struct scsiif_request_segment *)end_seg;
 517                 end_seg += ring_req->seg[0].length;
 518                 pg = pending_req->pages + nr_sgl;
 519         }
 520
 521         for_each_sg(pending_req->sgl, sg, nr_segments, i) {
 522                 sg_set_page(sg, pg[i], seg->length, seg->offset);
 523                 pending_req->data_len += seg->length;
 524                 seg++;
 525                 if (nr_sgl && (unsigned long)seg >= end_seg) {
 526                         i_seg++;
 527                         end_seg = vaddr(pending_req, i_seg) +
 528                                   ring_req->seg[i_seg].offset;
 529                         seg = (struct scsiif_request_segment *)end_seg;
 530                         end_seg += ring_req->seg[i_seg].length;
 531                 }
 532                 if (sg->offset >= PAGE_SIZE ||
 533                     sg->length > PAGE_SIZE ||
 534                     sg->offset + sg->length > PAGE_SIZE)
 535                         return -EINVAL;
 536         }
 537
 538         return 0;
 539 }
 540
 541 static void scsiback_disconnect(struct vscsibk_info *info)
 542 {
 543         wait_event(info->waiting_to_free,
 544                 atomic_read(&info->nr_unreplied_reqs) == 0);
 545
 546         unbind_from_irqhandler(info->irq, info);
 547         info->irq = 0;
 548         xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
 549 }
 550
 551 static void scsiback_device_action(struct vscsibk_pend *pending_req,
 552         enum tcm_tmreq_table act, int tag)
 553 {
 554         struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 555         struct scsiback_nexus *nexus = tpg->tpg_nexus;
 556         struct se_cmd *se_cmd = &pending_req->se_cmd;
 557         u64 unpacked_lun = pending_req->v2p->lun;
 558         int rc, err = FAILED;
 559
 560         init_completion(&pending_req->tmr_done);
 561
 562         rc = target_submit_tmr(&pending_req->se_cmd, nexus->tvn_se_sess,
 563                                &pending_req->sense_buffer[0],
 564                                unpacked_lun, NULL, act, GFP_KERNEL,
 565                                tag, TARGET_SCF_ACK_KREF);
 566         if (rc)
 567                 goto err;
 568
 569         wait_for_completion(&pending_req->tmr_done);
 570
 571         err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
 572                 SUCCESS : FAILED;
 573
 574         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 575         transport_generic_free_cmd(&pending_req->se_cmd, 0);
 576         return;
 577
 578 err:
 579         scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 580 }
 581
 582 /*
 583   Perform virtual to physical translation
 584 */
 585 static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
 586                         struct ids_tuple *v)
 587 {
 588         struct v2p_entry *entry;
 589         struct list_head *head = &(info->v2p_entry_lists);
 590         unsigned long flags;
 591
 592         spin_lock_irqsave(&info->v2p_lock, flags);
 593         list_for_each_entry(entry, head, l) {
 594                 if ((entry->v.chn == v->chn) &&
 595                     (entry->v.tgt == v->tgt) &&
 596                     (entry->v.lun == v->lun)) {
 597                         kref_get(&entry->kref);
 598                         goto out;
 599                 }
 600         }
 601         entry = NULL;
 602
 603 out:
 604         spin_unlock_irqrestore(&info->v2p_lock, flags);
 605         return entry;
 606 }
 607
 608 static struct vscsibk_pend *scsiback_get_pend_req(struct vscsiif_back_ring *ring,
 609                                 struct v2p_entry *v2p)
 610 {
 611         struct scsiback_tpg *tpg = v2p->tpg;
 612         struct scsiback_nexus *nexus = tpg->tpg_nexus;
 613         struct se_session *se_sess = nexus->tvn_se_sess;
 614         struct vscsibk_pend *req;
 615         int tag, cpu, i;
 616
 617         tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
 618         if (tag < 0) {
 619                 pr_err("Unable to obtain tag for vscsiif_request\n");
 620                 return ERR_PTR(-ENOMEM);
 621         }
 622
 623         req = &((struct vscsibk_pend *)se_sess->sess_cmd_map)[tag];
 624         memset(req, 0, sizeof(*req));
 625         req->se_cmd.map_tag = tag;
 626         req->se_cmd.map_cpu = cpu;
 627
 628         for (i = 0; i < VSCSI_MAX_GRANTS; i++)
 629                 req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 630
 631         return req;
 632 }
 633
 634 static struct vscsibk_pend *prepare_pending_reqs(struct vscsibk_info *info,
 635                                 struct vscsiif_back_ring *ring,
 636                                 struct vscsiif_request *ring_req)
 637 {
 638         struct vscsibk_pend *pending_req;
 639         struct v2p_entry *v2p;
 640         struct ids_tuple vir;
 641
 642         /* request range check from frontend */
 643         if ((ring_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
 644                 (ring_req->sc_data_direction != DMA_TO_DEVICE) &&
 645                 (ring_req->sc_data_direction != DMA_FROM_DEVICE) &&
 646                 (ring_req->sc_data_direction != DMA_NONE)) {
 647                 pr_debug("invalid parameter data_dir = %d\n",
 648                         ring_req->sc_data_direction);
 649                 return ERR_PTR(-EINVAL);
 650         }
 651         if (ring_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
 652                 pr_debug("invalid parameter cmd_len = %d\n",
 653                         ring_req->cmd_len);
 654                 return ERR_PTR(-EINVAL);
 655         }
 656
 657         vir.chn = ring_req->channel;
 658         vir.tgt = ring_req->id;
 659         vir.lun = ring_req->lun;
 660
 661         v2p = scsiback_do_translation(info, &vir);
 662         if (!v2p) {
 663                 pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
 664                          vir.chn, vir.tgt, vir.lun);
 665                 return ERR_PTR(-ENODEV);
 666         }
 667
 668         pending_req = scsiback_get_pend_req(ring, v2p);
 669         if (IS_ERR(pending_req)) {
 670                 kref_put(&v2p->kref, scsiback_free_translation_entry);
 671                 return ERR_PTR(-ENOMEM);
 672         }
 673         pending_req->rqid = ring_req->rqid;
 674         pending_req->info = info;
 675         pending_req->v2p = v2p;
 676         pending_req->sc_data_direction = ring_req->sc_data_direction;
 677         pending_req->cmd_len = ring_req->cmd_len;
 678         memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
 679
 680         return pending_req;
 681 }
 682
 683 static int scsiback_do_cmd_fn(struct vscsibk_info *info,
 684                               unsigned int *eoi_flags)
 685 {
 686         struct vscsiif_back_ring *ring = &info->ring;
 687         struct vscsiif_request ring_req;
 688         struct vscsibk_pend *pending_req;
 689         RING_IDX rc, rp;
 690         int more_to_do;
 691         uint32_t result;
 692
 693         rc = ring->req_cons;
 694         rp = ring->sring->req_prod;
 695         rmb();  /* guest system is accessing ring, too */
 696
 697         if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
 698                 rc = ring->rsp_prod_pvt;
 699                 pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 700                            info->domid, rp, rc, rp - rc);
 701                 return -EINVAL;
 702         }
 703
 704         while ((rc != rp)) {
 705                 *eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS;
 706
 707                 if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
 708                         break;
 709
 710                 RING_COPY_REQUEST(ring, rc, &ring_req);
 711                 ring->req_cons = ++rc;
 712
 713                 pending_req = prepare_pending_reqs(info, ring, &ring_req);
 714                 if (IS_ERR(pending_req)) {
 715                         switch (PTR_ERR(pending_req)) {
 716                         case -ENODEV:
 717                                 result = DID_NO_CONNECT;
 718                                 break;
 719                         default:
 720                                 result = DID_ERROR;
 721                                 break;
 722                         }
 723                         scsiback_send_response(info, NULL, result << 16, 0,
 724                                                ring_req.rqid);
 725                         return 1;
 726                 }
 727
 728                 switch (ring_req.act) {
 729                 case VSCSIIF_ACT_SCSI_CDB:
 730                         if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
 731                                 scsiback_fast_flush_area(pending_req);
 732                                 scsiback_do_resp_with_sense(NULL,
 733                                                 DID_ERROR << 16, 0, pending_req);
 734                                 transport_generic_free_cmd(&pending_req->se_cmd, 0);
 735                         } else {
 736                                 scsiback_cmd_exec(pending_req);
 737                         }
 738                         break;
 739                 case VSCSIIF_ACT_SCSI_ABORT:
 740                         scsiback_device_action(pending_req, TMR_ABORT_TASK,
 741                                 ring_req.ref_rqid);
 742                         break;
 743                 case VSCSIIF_ACT_SCSI_RESET:
 744                         scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
 745                         break;
 746                 default:
 747                         pr_err_ratelimited("invalid request\n");
 748                         scsiback_do_resp_with_sense(NULL, DID_ERROR << 16, 0,
 749                                                     pending_req);
 750                         transport_generic_free_cmd(&pending_req->se_cmd, 0);
 751                         break;
 752                 }
 753
 754                 /* Yield point for this unbounded loop. */
 755                 cond_resched();
 756         }
 757
 758         gnttab_page_cache_shrink(&info->free_pages, scsiback_max_buffer_pages);
 759
 760         RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
 761         return more_to_do;
 762 }
 763
 764 static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
 765 {
 766         struct vscsibk_info *info = dev_id;
 767         int rc;
 768         unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
 769
 770         while ((rc = scsiback_do_cmd_fn(info, &eoi_flags)) > 0)
 771                 cond_resched();
 772
 773         /* In case of a ring error we keep the event channel masked. */
 774         if (!rc)
 775                 xen_irq_lateeoi(irq, eoi_flags);
 776
 777         return IRQ_HANDLED;
 778 }
 779
 780 static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 781                         evtchn_port_t evtchn)
 782 {
 783         void *area;
 784         struct vscsiif_sring *sring;
 785         int err;
 786
 787         if (info->irq)
 788                 return -1;
 789
 790         err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 791         if (err)
 792                 return err;
 793
 794         sring = (struct vscsiif_sring *)area;
 795         BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 796
 797         err = bind_interdomain_evtchn_to_irq_lateeoi(info->dev, evtchn);
 798         if (err < 0)
 799                 goto unmap_page;
 800
 801         info->irq = err;
 802
 803         err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
 804                                    IRQF_ONESHOT, "vscsiif-backend", info);
 805         if (err)
 806                 goto free_irq;
 807
 808         return 0;
 809
 810 free_irq:
 811         unbind_from_irqhandler(info->irq, info);
 812         info->irq = 0;
 813 unmap_page:
 814         xenbus_unmap_ring_vfree(info->dev, area);
 815
 816         return err;
 817 }
 818
 819 static int scsiback_map(struct vscsibk_info *info)
 820 {
 821         struct xenbus_device *dev = info->dev;
 822         unsigned int ring_ref;
 823         evtchn_port_t evtchn;
 824         int err;
 825
 826         err = xenbus_gather(XBT_NIL, dev->otherend,
 827                         "ring-ref", "%u", &ring_ref,
 828                         "event-channel", "%u", &evtchn, NULL);
 829         if (err) {
 830                 xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
 831                 return err;
 832         }
 833
 834         return scsiback_init_sring(info, ring_ref, evtchn);
 835 }
 836
 837 /*
 838   Check for a translation entry being present
 839 */
 840 static struct v2p_entry *scsiback_chk_translation_entry(
 841         struct vscsibk_info *info, struct ids_tuple *v)
 842 {
 843         struct list_head *head = &(info->v2p_entry_lists);
 844         struct v2p_entry *entry;
 845
 846         list_for_each_entry(entry, head, l)
 847                 if ((entry->v.chn == v->chn) &&
 848                     (entry->v.tgt == v->tgt) &&
 849                     (entry->v.lun == v->lun))
 850                         return entry;
 851
 852         return NULL;
 853 }
 854
 855 /*
 856   Add a new translation entry
 857 */
 858 static int scsiback_add_translation_entry(struct vscsibk_info *info,
 859                                           char *phy, struct ids_tuple *v)
 860 {
 861         int err = 0;
 862         struct v2p_entry *new;
 863         unsigned long flags;
 864         char *lunp;
 865         unsigned long long unpacked_lun;
 866         struct se_lun *se_lun;
 867         struct scsiback_tpg *tpg_entry, *tpg = NULL;
 868         char *error = "doesn't exist";
 869
 870         lunp = strrchr(phy, ':');
 871         if (!lunp) {
 872                 pr_err("illegal format of physical device %s\n", phy);
 873                 return -EINVAL;
 874         }
 875         *lunp = 0;
 876         lunp++;
 877         err = kstrtoull(lunp, 10, &unpacked_lun);
 878         if (err < 0) {
 879                 pr_err("lun number not valid: %s\n", lunp);
 880                 return err;
 881         }
 882
 883         mutex_lock(&scsiback_mutex);
 884         list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
 885                 if (!strcmp(phy, tpg_entry->tport->tport_name) ||
 886                     !strcmp(phy, tpg_entry->param_alias)) {
 887                         mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
 888                         hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
 889                                 if (se_lun->unpacked_lun == unpacked_lun) {
 890                                         if (!tpg_entry->tpg_nexus)
 891                                                 error = "nexus undefined";
 892                                         else
 893                                                 tpg = tpg_entry;
 894                                         break;
 895                                 }
 896                         }
 897                         mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
 898                         break;
 899                 }
 900         }
 901         if (tpg) {
 902                 mutex_lock(&tpg->tv_tpg_mutex);
 903                 tpg->tv_tpg_fe_count++;
 904                 mutex_unlock(&tpg->tv_tpg_mutex);
 905         }
 906         mutex_unlock(&scsiback_mutex);
 907
 908         if (!tpg) {
 909                 pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
 910                 return -ENODEV;
 911         }
 912
 913         new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
 914         if (new == NULL) {
 915                 err = -ENOMEM;
 916                 goto out_free;
 917         }
 918
 919         spin_lock_irqsave(&info->v2p_lock, flags);
 920
 921         /* Check double assignment to identical virtual ID */
 922         if (scsiback_chk_translation_entry(info, v)) {
 923                 pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 924                 err = -EEXIST;
 925                 goto out;
 926         }
 927
 928         /* Create a new translation entry and add to the list */
 929         kref_init(&new->kref);
 930         new->v = *v;
 931         new->tpg = tpg;
 932         new->lun = unpacked_lun;
 933         list_add_tail(&new->l, &info->v2p_entry_lists);
 934
 935 out:
 936         spin_unlock_irqrestore(&info->v2p_lock, flags);
 937
 938 out_free:
 939         if (err) {
 940                 mutex_lock(&tpg->tv_tpg_mutex);
 941                 tpg->tv_tpg_fe_count--;
 942                 mutex_unlock(&tpg->tv_tpg_mutex);
 943                 kfree(new);
 944         }
 945
 946         return err;
 947 }
 948
 949 static void __scsiback_del_translation_entry(struct v2p_entry *entry)
 950 {
 951         list_del(&entry->l);
 952         kref_put(&entry->kref, scsiback_free_translation_entry);
 953 }
 954
 955 /*
 956   Delete the translation entry specified
 957 */
 958 static int scsiback_del_translation_entry(struct vscsibk_info *info,
 959                                           struct ids_tuple *v)
 960 {
 961         struct v2p_entry *entry;
 962         unsigned long flags;
 963         int ret = 0;
 964
 965         spin_lock_irqsave(&info->v2p_lock, flags);
 966         /* Find out the translation entry specified */
 967         entry = scsiback_chk_translation_entry(info, v);
 968         if (entry)
 969                 __scsiback_del_translation_entry(entry);
 970         else
 971                 ret = -ENOENT;
 972
 973         spin_unlock_irqrestore(&info->v2p_lock, flags);
 974         return ret;
 975 }
 976
 977 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
 978                                 char *phy, struct ids_tuple *vir, int try)
 979 {
 980         struct v2p_entry *entry;
 981         unsigned long flags;
 982         int err;
 983
 984         if (try) {
 985                 spin_lock_irqsave(&info->v2p_lock, flags);
 986                 entry = scsiback_chk_translation_entry(info, vir);
 987                 spin_unlock_irqrestore(&info->v2p_lock, flags);
 988                 if (entry)
 989                         return;
 990         }
 991         if (!scsiback_add_translation_entry(info, phy, vir)) {
 992                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
 993                                   "%d", XenbusStateInitialised)) {
 994                         pr_err("xenbus_printf error %s\n", state);
 995                         scsiback_del_translation_entry(info, vir);
 996                 }
 997         } else if (!try) {
 998                 err = xenbus_printf(XBT_NIL, info->dev->nodename, state,
 999                               "%d", XenbusStateClosed);
1000                 if (err)
1001                         xenbus_dev_error(info->dev, err,
1002                                 "%s: writing %s", __func__, state);
1003         }
1004 }
1005
1006 static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1007                                 struct ids_tuple *vir)
1008 {
1009         if (!scsiback_del_translation_entry(info, vir)) {
1010                 if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1011                                   "%d", XenbusStateClosed))
1012                         pr_err("xenbus_printf error %s\n", state);
1013         }
1014 }
1015
1016 #define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1017 #define VSCSIBACK_OP_UPDATEDEV_STATE    2
1018
1019 static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1020                                      char *ent)
1021 {
1022         int err;
1023         struct ids_tuple vir;
1024         char *val;
1025         int device_state;
1026         char phy[VSCSI_NAMELEN];
1027         char str[64];
1028         char state[64];
1029         struct xenbus_device *dev = info->dev;
1030
1031         /* read status */
1032         snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1033         err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1034         if (XENBUS_EXIST_ERR(err))
1035                 return;
1036
1037         /* physical SCSI device */
1038         snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1039         val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1040         if (IS_ERR(val)) {
1041                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1042                               "%d", XenbusStateClosed);
1043                 if (err)
1044                         xenbus_dev_error(info->dev, err,
1045                                 "%s: writing %s", __func__, state);
1046                 return;
1047         }
1048         strlcpy(phy, val, VSCSI_NAMELEN);
1049         kfree(val);
1050
1051         /* virtual SCSI device */
1052         snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1053         err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1054                            &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1055         if (XENBUS_EXIST_ERR(err)) {
1056                 err = xenbus_printf(XBT_NIL, dev->nodename, state,
1057                               "%d", XenbusStateClosed);
1058                 if (err)
1059                         xenbus_dev_error(info->dev, err,
1060                                 "%s: writing %s", __func__, state);
1061                 return;
1062         }
1063
1064         switch (op) {
1065         case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1066                 switch (device_state) {
1067                 case XenbusStateInitialising:
1068                         scsiback_do_add_lun(info, state, phy, &vir, 0);
1069                         break;
1070                 case XenbusStateConnected:
1071                         scsiback_do_add_lun(info, state, phy, &vir, 1);
1072                         break;
1073                 case XenbusStateClosing:
1074                         scsiback_do_del_lun(info, state, &vir);
1075                         break;
1076                 default:
1077                         break;
1078                 }
1079                 break;
1080
1081         case VSCSIBACK_OP_UPDATEDEV_STATE:
1082                 if (device_state == XenbusStateInitialised) {
1083                         /* modify vscsi-devs/dev-x/state */
1084                         if (xenbus_printf(XBT_NIL, dev->nodename, state,
1085                                           "%d", XenbusStateConnected)) {
1086                                 pr_err("xenbus_printf error %s\n", str);
1087                                 scsiback_del_translation_entry(info, &vir);
1088                                 xenbus_printf(XBT_NIL, dev->nodename, state,
1089                                               "%d", XenbusStateClosed);
1090                         }
1091                 }
1092                 break;
1093         /* When it is necessary, processing is added here. */
1094         default:
1095                 break;
1096         }
1097 }
1098
1099 static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1100 {
1101         int i;
1102         char **dir;
1103         unsigned int ndir = 0;
1104
1105         dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1106                                &ndir);
1107         if (IS_ERR(dir))
1108                 return;
1109
1110         for (i = 0; i < ndir; i++)
1111                 scsiback_do_1lun_hotplug(info, op, dir[i]);
1112
1113         kfree(dir);
1114 }
1115
1116 static void scsiback_frontend_changed(struct xenbus_device *dev,
1117                                         enum xenbus_state frontend_state)
1118 {
1119         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1120
1121         switch (frontend_state) {
1122         case XenbusStateInitialising:
1123                 break;
1124
1125         case XenbusStateInitialised:
1126                 if (scsiback_map(info))
1127                         break;
1128
1129                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1130                 xenbus_switch_state(dev, XenbusStateConnected);
1131                 break;
1132
1133         case XenbusStateConnected:
1134                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1135
1136                 if (dev->state == XenbusStateConnected)
1137                         break;
1138
1139                 xenbus_switch_state(dev, XenbusStateConnected);
1140                 break;
1141
1142         case XenbusStateClosing:
1143                 if (info->irq)
1144                         scsiback_disconnect(info);
1145
1146                 xenbus_switch_state(dev, XenbusStateClosing);
1147                 break;
1148
1149         case XenbusStateClosed:
1150                 xenbus_switch_state(dev, XenbusStateClosed);
1151                 if (xenbus_dev_is_online(dev))
1152                         break;
1153                 fallthrough;    /* if not online */
1154         case XenbusStateUnknown:
1155                 device_unregister(&dev->dev);
1156                 break;
1157
1158         case XenbusStateReconfiguring:
1159                 scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1160                 xenbus_switch_state(dev, XenbusStateReconfigured);
1161
1162                 break;
1163
1164         default:
1165                 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1166                                         frontend_state);
1167                 break;
1168         }
1169 }
1170
1171 /*
1172   Release the translation entry specfied
1173 */
1174 static void scsiback_release_translation_entry(struct vscsibk_info *info)
1175 {
1176         struct v2p_entry *entry, *tmp;
1177         struct list_head *head = &(info->v2p_entry_lists);
1178         unsigned long flags;
1179
1180         spin_lock_irqsave(&info->v2p_lock, flags);
1181
1182         list_for_each_entry_safe(entry, tmp, head, l)
1183                 __scsiback_del_translation_entry(entry);
1184
1185         spin_unlock_irqrestore(&info->v2p_lock, flags);
1186 }
1187
1188 static int scsiback_remove(struct xenbus_device *dev)
1189 {
1190         struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1191
1192         if (info->irq)
1193                 scsiback_disconnect(info);
1194
1195         scsiback_release_translation_entry(info);
1196
1197         gnttab_page_cache_shrink(&info->free_pages, 0);
1198
1199         dev_set_drvdata(&dev->dev, NULL);
1200
1201         return 0;
1202 }
1203
1204 static int scsiback_probe(struct xenbus_device *dev,
1205                            const struct xenbus_device_id *id)
1206 {
1207         int err;
1208
1209         struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1210                                             GFP_KERNEL);
1211
1212         pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1213
1214         if (!info) {
1215                 xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1216                 return -ENOMEM;
1217         }
1218         info->dev = dev;
1219         dev_set_drvdata(&dev->dev, info);
1220
1221         info->domid = dev->otherend_id;
1222         spin_lock_init(&info->ring_lock);
1223         atomic_set(&info->nr_unreplied_reqs, 0);
1224         init_waitqueue_head(&info->waiting_to_free);
1225         info->dev = dev;
1226         info->irq = 0;
1227         INIT_LIST_HEAD(&info->v2p_entry_lists);
1228         spin_lock_init(&info->v2p_lock);
1229         gnttab_page_cache_init(&info->free_pages);
1230
1231         err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1232                             SG_ALL);
1233         if (err)
1234                 xenbus_dev_error(dev, err, "writing feature-sg-grant");
1235
1236         err = xenbus_switch_state(dev, XenbusStateInitWait);
1237         if (err)
1238                 goto fail;
1239
1240         return 0;
1241
1242 fail:
1243         pr_warn("%s failed\n", __func__);
1244         scsiback_remove(dev);
1245
1246         return err;
1247 }
1248
1249 static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1250 {
1251         switch (tport->tport_proto_id) {
1252         case SCSI_PROTOCOL_SAS:
1253                 return "SAS";
1254         case SCSI_PROTOCOL_FCP:
1255                 return "FCP";
1256         case SCSI_PROTOCOL_ISCSI:
1257                 return "iSCSI";
1258         default:
1259                 break;
1260         }
1261
1262         return "Unknown";
1263 }
1264
1265 static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1266 {
1267         struct scsiback_tpg *tpg = container_of(se_tpg,
1268                                 struct scsiback_tpg, se_tpg);
1269         struct scsiback_tport *tport = tpg->tport;
1270
1271         return &tport->tport_name[0];
1272 }
1273
1274 static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1275 {
1276         struct scsiback_tpg *tpg = container_of(se_tpg,
1277                                 struct scsiback_tpg, se_tpg);
1278         return tpg->tport_tpgt;
1279 }
1280
1281 static struct se_wwn *
1282 scsiback_make_tport(struct target_fabric_configfs *tf,
1283                      struct config_group *group,
1284                      const char *name)
1285 {
1286         struct scsiback_tport *tport;
1287         char *ptr;
1288         u64 wwpn = 0;
1289         int off = 0;
1290
1291         tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1292         if (!tport)
1293                 return ERR_PTR(-ENOMEM);
1294
1295         tport->tport_wwpn = wwpn;
1296         /*
1297          * Determine the emulated Protocol Identifier and Target Port Name
1298          * based on the incoming configfs directory name.
1299          */
1300         ptr = strstr(name, "naa.");
1301         if (ptr) {
1302                 tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1303                 goto check_len;
1304         }
1305         ptr = strstr(name, "fc.");
1306         if (ptr) {
1307                 tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1308                 off = 3; /* Skip over "fc." */
1309                 goto check_len;
1310         }
1311         ptr = strstr(name, "iqn.");
1312         if (ptr) {
1313                 tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1314                 goto check_len;
1315         }
1316
1317         pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1318         kfree(tport);
1319         return ERR_PTR(-EINVAL);
1320
1321 check_len:
1322         if (strlen(name) >= VSCSI_NAMELEN) {
1323                 pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1324                         scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1325                 kfree(tport);
1326                 return ERR_PTR(-EINVAL);
1327         }
1328         snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1329
1330         pr_debug("Allocated emulated Target %s Address: %s\n",
1331                  scsiback_dump_proto_id(tport), name);
1332
1333         return &tport->tport_wwn;
1334 }
1335
1336 static void scsiback_drop_tport(struct se_wwn *wwn)
1337 {
1338         struct scsiback_tport *tport = container_of(wwn,
1339                                 struct scsiback_tport, tport_wwn);
1340
1341         pr_debug("Deallocating emulated Target %s Address: %s\n",
1342                  scsiback_dump_proto_id(tport), tport->tport_name);
1343
1344         kfree(tport);
1345 }
1346
1347 static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1348 {
1349         return 1;
1350 }
1351
1352 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1353 {
1354         return transport_generic_free_cmd(se_cmd, 0);
1355 }
1356
1357 static void scsiback_release_cmd(struct se_cmd *se_cmd)
1358 {
1359         target_free_tag(se_cmd->se_sess, se_cmd);
1360 }
1361
1362 static u32 scsiback_sess_get_index(struct se_session *se_sess)
1363 {
1364         return 0;
1365 }
1366
1367 static int scsiback_write_pending(struct se_cmd *se_cmd)
1368 {
1369         /* Go ahead and process the write immediately */
1370         target_execute_cmd(se_cmd);
1371
1372         return 0;
1373 }
1374
1375 static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1376 {
1377 }
1378
1379 static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1380 {
1381         return 0;
1382 }
1383
1384 static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1385 {
1386         struct vscsibk_pend *pending_req = container_of(se_cmd,
1387                                 struct vscsibk_pend, se_cmd);
1388
1389         pending_req->result = SAM_STAT_GOOD;
1390         scsiback_cmd_done(pending_req);
1391         return 0;
1392 }
1393
1394 static int scsiback_queue_status(struct se_cmd *se_cmd)
1395 {
1396         struct vscsibk_pend *pending_req = container_of(se_cmd,
1397                                 struct vscsibk_pend, se_cmd);
1398
1399         if (se_cmd->sense_buffer &&
1400             ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1401              (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1402                 pending_req->result = SAM_STAT_CHECK_CONDITION;
1403         else
1404                 pending_req->result = se_cmd->scsi_status;
1405
1406         scsiback_cmd_done(pending_req);
1407         return 0;
1408 }
1409
1410 static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1411 {
1412         struct vscsibk_pend *pending_req = container_of(se_cmd,
1413                                 struct vscsibk_pend, se_cmd);
1414
1415         complete(&pending_req->tmr_done);
1416 }
1417
1418 static void scsiback_aborted_task(struct se_cmd *se_cmd)
1419 {
1420 }
1421
1422 static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1423                                              char *page)
1424 {
1425         struct se_portal_group *se_tpg = param_to_tpg(item);
1426         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1427                                                 se_tpg);
1428         ssize_t rb;
1429
1430         mutex_lock(&tpg->tv_tpg_mutex);
1431         rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1432         mutex_unlock(&tpg->tv_tpg_mutex);
1433
1434         return rb;
1435 }
1436
1437 static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1438                                               const char *page, size_t count)
1439 {
1440         struct se_portal_group *se_tpg = param_to_tpg(item);
1441         struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1442                                                 se_tpg);
1443         int len;
1444
1445         if (strlen(page) >= VSCSI_NAMELEN) {
1446                 pr_err("param alias: %s, exceeds max: %d\n", page,
1447                         VSCSI_NAMELEN);
1448                 return -EINVAL;
1449         }
1450
1451         mutex_lock(&tpg->tv_tpg_mutex);
1452         len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1453         if (tpg->param_alias[len - 1] == '\n')
1454                 tpg->param_alias[len - 1] = '\0';
1455         mutex_unlock(&tpg->tv_tpg_mutex);
1456
1457         return count;
1458 }
1459
1460 CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1461
1462 static struct configfs_attribute *scsiback_param_attrs[] = {
1463         &scsiback_tpg_param_attr_alias,
1464         NULL,
1465 };
1466
1467 static int scsiback_alloc_sess_cb(struct se_portal_group *se_tpg,
1468                                   struct se_session *se_sess, void *p)
1469 {
1470         struct scsiback_tpg *tpg = container_of(se_tpg,
1471                                 struct scsiback_tpg, se_tpg);
1472
1473         tpg->tpg_nexus = p;
1474         return 0;
1475 }
1476
1477 static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1478                                 const char *name)
1479 {
1480         struct scsiback_nexus *tv_nexus;
1481         int ret = 0;
1482
1483         mutex_lock(&tpg->tv_tpg_mutex);
1484         if (tpg->tpg_nexus) {
1485                 pr_debug("tpg->tpg_nexus already exists\n");
1486                 ret = -EEXIST;
1487                 goto out_unlock;
1488         }
1489
1490         tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1491         if (!tv_nexus) {
1492                 ret = -ENOMEM;
1493                 goto out_unlock;
1494         }
1495
1496         tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg,
1497                                                      VSCSI_DEFAULT_SESSION_TAGS,
1498                                                      sizeof(struct vscsibk_pend),
1499                                                      TARGET_PROT_NORMAL, name,
1500                                                      tv_nexus, scsiback_alloc_sess_cb);
1501         if (IS_ERR(tv_nexus->tvn_se_sess)) {
1502                 kfree(tv_nexus);
1503                 ret = -ENOMEM;
1504                 goto out_unlock;
1505         }
1506
1507 out_unlock:
1508         mutex_unlock(&tpg->tv_tpg_mutex);
1509         return ret;
1510 }
1511
1512 static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1513 {
1514         struct se_session *se_sess;
1515         struct scsiback_nexus *tv_nexus;
1516
1517         mutex_lock(&tpg->tv_tpg_mutex);
1518         tv_nexus = tpg->tpg_nexus;
1519         if (!tv_nexus) {
1520                 mutex_unlock(&tpg->tv_tpg_mutex);
1521                 return -ENODEV;
1522         }
1523
1524         se_sess = tv_nexus->tvn_se_sess;
1525         if (!se_sess) {
1526                 mutex_unlock(&tpg->tv_tpg_mutex);
1527                 return -ENODEV;
1528         }
1529
1530         if (tpg->tv_tpg_port_count != 0) {
1531                 mutex_unlock(&tpg->tv_tpg_mutex);
1532                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1533                         tpg->tv_tpg_port_count);
1534                 return -EBUSY;
1535         }
1536
1537         if (tpg->tv_tpg_fe_count != 0) {
1538                 mutex_unlock(&tpg->tv_tpg_mutex);
1539                 pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1540                         tpg->tv_tpg_fe_count);
1541                 return -EBUSY;
1542         }
1543
1544         pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1545                 scsiback_dump_proto_id(tpg->tport),
1546                 tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1547
1548         /*
1549          * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1550          */
1551         target_remove_session(se_sess);
1552         tpg->tpg_nexus = NULL;
1553         mutex_unlock(&tpg->tv_tpg_mutex);
1554
1555         kfree(tv_nexus);
1556         return 0;
1557 }
1558
1559 static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1560 {
1561         struct se_portal_group *se_tpg = to_tpg(item);
1562         struct scsiback_tpg *tpg = container_of(se_tpg,
1563                                 struct scsiback_tpg, se_tpg);
1564         struct scsiback_nexus *tv_nexus;
1565         ssize_t ret;
1566
1567         mutex_lock(&tpg->tv_tpg_mutex);
1568         tv_nexus = tpg->tpg_nexus;
1569         if (!tv_nexus) {
1570                 mutex_unlock(&tpg->tv_tpg_mutex);
1571                 return -ENODEV;
1572         }
1573         ret = snprintf(page, PAGE_SIZE, "%s\n",
1574                         tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1575         mutex_unlock(&tpg->tv_tpg_mutex);
1576
1577         return ret;
1578 }
1579
1580 static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
1581                 const char *page, size_t count)
1582 {
1583         struct se_portal_group *se_tpg = to_tpg(item);
1584         struct scsiback_tpg *tpg = container_of(se_tpg,
1585                                 struct scsiback_tpg, se_tpg);
1586         struct scsiback_tport *tport_wwn = tpg->tport;
1587         unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1588         int ret;
1589         /*
1590          * Shutdown the active I_T nexus if 'NULL' is passed.
1591          */
1592         if (!strncmp(page, "NULL", 4)) {
1593                 ret = scsiback_drop_nexus(tpg);
1594                 return (!ret) ? count : ret;
1595         }
1596         /*
1597          * Otherwise make sure the passed virtual Initiator port WWN matches
1598          * the fabric protocol_id set in scsiback_make_tport(), and call
1599          * scsiback_make_nexus().
1600          */
1601         if (strlen(page) >= VSCSI_NAMELEN) {
1602                 pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1603                         page, VSCSI_NAMELEN);
1604                 return -EINVAL;
1605         }
1606         snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1607
1608         ptr = strstr(i_port, "naa.");
1609         if (ptr) {
1610                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1611                         pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1612                                 i_port, scsiback_dump_proto_id(tport_wwn));
1613                         return -EINVAL;
1614                 }
1615                 port_ptr = &i_port[0];
1616                 goto check_newline;
1617         }
1618         ptr = strstr(i_port, "fc.");
1619         if (ptr) {
1620                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1621                         pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1622                                 i_port, scsiback_dump_proto_id(tport_wwn));
1623                         return -EINVAL;
1624                 }
1625                 port_ptr = &i_port[3]; /* Skip over "fc." */
1626                 goto check_newline;
1627         }
1628         ptr = strstr(i_port, "iqn.");
1629         if (ptr) {
1630                 if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1631                         pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1632                                 i_port, scsiback_dump_proto_id(tport_wwn));
1633                         return -EINVAL;
1634                 }
1635                 port_ptr = &i_port[0];
1636                 goto check_newline;
1637         }
1638         pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1639                 i_port);
1640         return -EINVAL;
1641         /*
1642          * Clear any trailing newline for the NAA WWN
1643          */
1644 check_newline:
1645         if (i_port[strlen(i_port) - 1] == '\n')
1646                 i_port[strlen(i_port) - 1] = '\0';
1647
1648         ret = scsiback_make_nexus(tpg, port_ptr);
1649         if (ret < 0)
1650                 return ret;
1651
1652         return count;
1653 }
1654
1655 CONFIGFS_ATTR(scsiback_tpg_, nexus);
1656
1657 static struct configfs_attribute *scsiback_tpg_attrs[] = {
1658         &scsiback_tpg_attr_nexus,
1659         NULL,
1660 };
1661
1662 static ssize_t
1663 scsiback_wwn_version_show(struct config_item *item, char *page)
1664 {
1665         return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1666                 UTS_RELEASE"\n",
1667                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1668 }
1669
1670 CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1671
1672 static struct configfs_attribute *scsiback_wwn_attrs[] = {
1673         &scsiback_wwn_attr_version,
1674         NULL,
1675 };
1676
1677 static int scsiback_port_link(struct se_portal_group *se_tpg,
1678                                struct se_lun *lun)
1679 {
1680         struct scsiback_tpg *tpg = container_of(se_tpg,
1681                                 struct scsiback_tpg, se_tpg);
1682
1683         mutex_lock(&tpg->tv_tpg_mutex);
1684         tpg->tv_tpg_port_count++;
1685         mutex_unlock(&tpg->tv_tpg_mutex);
1686
1687         return 0;
1688 }
1689
1690 static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1691                                   struct se_lun *lun)
1692 {
1693         struct scsiback_tpg *tpg = container_of(se_tpg,
1694                                 struct scsiback_tpg, se_tpg);
1695
1696         mutex_lock(&tpg->tv_tpg_mutex);
1697         tpg->tv_tpg_port_count--;
1698         mutex_unlock(&tpg->tv_tpg_mutex);
1699 }
1700
1701 static struct se_portal_group *
1702 scsiback_make_tpg(struct se_wwn *wwn, const char *name)
1703 {
1704         struct scsiback_tport *tport = container_of(wwn,
1705                         struct scsiback_tport, tport_wwn);
1706
1707         struct scsiback_tpg *tpg;
1708         u16 tpgt;
1709         int ret;
1710
1711         if (strstr(name, "tpgt_") != name)
1712                 return ERR_PTR(-EINVAL);
1713         ret = kstrtou16(name + 5, 10, &tpgt);
1714         if (ret)
1715                 return ERR_PTR(ret);
1716
1717         tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1718         if (!tpg)
1719                 return ERR_PTR(-ENOMEM);
1720
1721         mutex_init(&tpg->tv_tpg_mutex);
1722         INIT_LIST_HEAD(&tpg->tv_tpg_list);
1723         INIT_LIST_HEAD(&tpg->info_list);
1724         tpg->tport = tport;
1725         tpg->tport_tpgt = tpgt;
1726
1727         ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1728         if (ret < 0) {
1729                 kfree(tpg);
1730                 return NULL;
1731         }
1732         mutex_lock(&scsiback_mutex);
1733         list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1734         mutex_unlock(&scsiback_mutex);
1735
1736         return &tpg->se_tpg;
1737 }
1738
1739 static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1740 {
1741         struct scsiback_tpg *tpg = container_of(se_tpg,
1742                                 struct scsiback_tpg, se_tpg);
1743
1744         mutex_lock(&scsiback_mutex);
1745         list_del(&tpg->tv_tpg_list);
1746         mutex_unlock(&scsiback_mutex);
1747         /*
1748          * Release the virtual I_T Nexus for this xen-pvscsi TPG
1749          */
1750         scsiback_drop_nexus(tpg);
1751         /*
1752          * Deregister the se_tpg from TCM.
1753          */
1754         core_tpg_deregister(se_tpg);
1755         kfree(tpg);
1756 }
1757
1758 static int scsiback_check_true(struct se_portal_group *se_tpg)
1759 {
1760         return 1;
1761 }
1762
1763 static int scsiback_check_false(struct se_portal_group *se_tpg)
1764 {
1765         return 0;
1766 }
1767
1768 static const struct target_core_fabric_ops scsiback_ops = {
1769         .module                         = THIS_MODULE,
1770         .fabric_name                    = "xen-pvscsi",
1771         .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1772         .tpg_get_tag                    = scsiback_get_tag,
1773         .tpg_check_demo_mode            = scsiback_check_true,
1774         .tpg_check_demo_mode_cache      = scsiback_check_true,
1775         .tpg_check_demo_mode_write_protect = scsiback_check_false,
1776         .tpg_check_prod_mode_write_protect = scsiback_check_false,
1777         .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1778         .check_stop_free                = scsiback_check_stop_free,
1779         .release_cmd                    = scsiback_release_cmd,
1780         .sess_get_index                 = scsiback_sess_get_index,
1781         .sess_get_initiator_sid         = NULL,
1782         .write_pending                  = scsiback_write_pending,
1783         .set_default_node_attributes    = scsiback_set_default_node_attrs,
1784         .get_cmd_state                  = scsiback_get_cmd_state,
1785         .queue_data_in                  = scsiback_queue_data_in,
1786         .queue_status                   = scsiback_queue_status,
1787         .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1788         .aborted_task                   = scsiback_aborted_task,
1789         /*
1790          * Setup callers for generic logic in target_core_fabric_configfs.c
1791          */
1792         .fabric_make_wwn                = scsiback_make_tport,
1793         .fabric_drop_wwn                = scsiback_drop_tport,
1794         .fabric_make_tpg                = scsiback_make_tpg,
1795         .fabric_drop_tpg                = scsiback_drop_tpg,
1796         .fabric_post_link               = scsiback_port_link,
1797         .fabric_pre_unlink              = scsiback_port_unlink,
1798
1799         .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1800         .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1801         .tfc_tpg_param_attrs            = scsiback_param_attrs,
1802 };
1803
1804 static const struct xenbus_device_id scsiback_ids[] = {
1805         { "vscsi" },
1806         { "" }
1807 };
1808
1809 static struct xenbus_driver scsiback_driver = {
1810         .ids                    = scsiback_ids,
1811         .probe                  = scsiback_probe,
1812         .remove                 = scsiback_remove,
1813         .otherend_changed       = scsiback_frontend_changed
1814 };
1815
1816 static int __init scsiback_init(void)
1817 {
1818         int ret;
1819
1820         if (!xen_domain())
1821                 return -ENODEV;
1822
1823         pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1824                  VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1825
1826         ret = xenbus_register_backend(&scsiback_driver);
1827         if (ret)
1828                 goto out;
1829
1830         ret = target_register_template(&scsiback_ops);
1831         if (ret)
1832                 goto out_unregister_xenbus;
1833
1834         return 0;
1835
1836 out_unregister_xenbus:
1837         xenbus_unregister_driver(&scsiback_driver);
1838 out:
1839         pr_err("%s: error %d\n", __func__, ret);
1840         return ret;
1841 }
1842
1843 static void __exit scsiback_exit(void)
1844 {
1845         target_unregister_template(&scsiback_ops);
1846         xenbus_unregister_driver(&scsiback_driver);
1847 }
1848
1849 module_init(scsiback_init);
1850 module_exit(scsiback_exit);
1851
1852 MODULE_DESCRIPTION("Xen SCSI backend driver");
1853 MODULE_LICENSE("Dual BSD/GPL");
1854 MODULE_ALIAS("xen-backend:vscsi");
1855 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");