linux/drivers/xen/xen-scsiback.c
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   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#include <target/target_core_fabric_configfs.h>
  57
  58#include <asm/hypervisor.h>
  59
  60#include <xen/xen.h>
  61#include <xen/balloon.h>
  62#include <xen/events.h>
  63#include <xen/xenbus.h>
  64#include <xen/grant_table.h>
  65#include <xen/page.h>
  66
  67#include <xen/interface/grant_table.h>
  68#include <xen/interface/io/vscsiif.h>
  69
  70#define VSCSI_VERSION   "v0.1"
  71#define VSCSI_NAMELEN   32
  72
  73struct ids_tuple {
  74        unsigned int hst;               /* host    */
  75        unsigned int chn;               /* channel */
  76        unsigned int tgt;               /* target  */
  77        unsigned int lun;               /* LUN     */
  78};
  79
  80struct v2p_entry {
  81        struct ids_tuple v;             /* translate from */
  82        struct scsiback_tpg *tpg;       /* translate to   */
  83        unsigned int lun;
  84        struct kref kref;
  85        struct list_head l;
  86};
  87
  88struct vscsibk_info {
  89        struct xenbus_device *dev;
  90
  91        domid_t domid;
  92        unsigned int irq;
  93
  94        struct vscsiif_back_ring ring;
  95        int ring_error;
  96
  97        spinlock_t ring_lock;
  98        atomic_t nr_unreplied_reqs;
  99
 100        spinlock_t v2p_lock;
 101        struct list_head v2p_entry_lists;
 102
 103        wait_queue_head_t waiting_to_free;
 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
 116struct 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
 140struct scsiback_tmr {
 141        atomic_t tmr_complete;
 142        wait_queue_head_t tmr_wait;
 143};
 144
 145struct scsiback_nexus {
 146        /* Pointer to TCM session for I_T Nexus */
 147        struct se_session *tvn_se_sess;
 148};
 149
 150struct scsiback_tport {
 151        /* SCSI protocol the tport is providing */
 152        u8 tport_proto_id;
 153        /* Binary World Wide unique Port Name for pvscsi Target port */
 154        u64 tport_wwpn;
 155        /* ASCII formatted WWPN for pvscsi Target port */
 156        char tport_name[VSCSI_NAMELEN];
 157        /* Returned by scsiback_make_tport() */
 158        struct se_wwn tport_wwn;
 159};
 160
 161struct scsiback_tpg {
 162        /* scsiback port target portal group tag for TCM */
 163        u16 tport_tpgt;
 164        /* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
 165        int tv_tpg_port_count;
 166        /* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
 167        int tv_tpg_fe_count;
 168        /* list for scsiback_list */
 169        struct list_head tv_tpg_list;
 170        /* Used to protect access for tpg_nexus */
 171        struct mutex tv_tpg_mutex;
 172        /* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
 173        struct scsiback_nexus *tpg_nexus;
 174        /* Pointer back to scsiback_tport */
 175        struct scsiback_tport *tport;
 176        /* Returned by scsiback_make_tpg() */
 177        struct se_portal_group se_tpg;
 178        /* alias used in xenstore */
 179        char param_alias[VSCSI_NAMELEN];
 180        /* list of info structures related to this target portal group */
 181        struct list_head info_list;
 182};
 183
 184#define SCSIBACK_INVALID_HANDLE (~0)
 185
 186static bool log_print_stat;
 187module_param(log_print_stat, bool, 0644);
 188
 189static int scsiback_max_buffer_pages = 1024;
 190module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
 191MODULE_PARM_DESC(max_buffer_pages,
 192"Maximum number of free pages to keep in backend buffer");
 193
 194static struct kmem_cache *scsiback_cachep;
 195static DEFINE_SPINLOCK(free_pages_lock);
 196static int free_pages_num;
 197static LIST_HEAD(scsiback_free_pages);
 198
 199/* Global spinlock to protect scsiback TPG list */
 200static DEFINE_MUTEX(scsiback_mutex);
 201static LIST_HEAD(scsiback_list);
 202
 203static void scsiback_get(struct vscsibk_info *info)
 204{
 205        atomic_inc(&info->nr_unreplied_reqs);
 206}
 207
 208static void scsiback_put(struct vscsibk_info *info)
 209{
 210        if (atomic_dec_and_test(&info->nr_unreplied_reqs))
 211                wake_up(&info->waiting_to_free);
 212}
 213
 214static void put_free_pages(struct page **page, int num)
 215{
 216        unsigned long flags;
 217        int i = free_pages_num + num, n = num;
 218
 219        if (num == 0)
 220                return;
 221        if (i > scsiback_max_buffer_pages) {
 222                n = min(num, i - scsiback_max_buffer_pages);
 223                gnttab_free_pages(n, page + num - n);
 224                n = num - n;
 225        }
 226        spin_lock_irqsave(&free_pages_lock, flags);
 227        for (i = 0; i < n; i++)
 228                list_add(&page[i]->lru, &scsiback_free_pages);
 229        free_pages_num += n;
 230        spin_unlock_irqrestore(&free_pages_lock, flags);
 231}
 232
 233static int get_free_page(struct page **page)
 234{
 235        unsigned long flags;
 236
 237        spin_lock_irqsave(&free_pages_lock, flags);
 238        if (list_empty(&scsiback_free_pages)) {
 239                spin_unlock_irqrestore(&free_pages_lock, flags);
 240                return gnttab_alloc_pages(1, page);
 241        }
 242        page[0] = list_first_entry(&scsiback_free_pages, struct page, lru);
 243        list_del(&page[0]->lru);
 244        free_pages_num--;
 245        spin_unlock_irqrestore(&free_pages_lock, flags);
 246        return 0;
 247}
 248
 249static unsigned long vaddr_page(struct page *page)
 250{
 251        unsigned long pfn = page_to_pfn(page);
 252
 253        return (unsigned long)pfn_to_kaddr(pfn);
 254}
 255
 256static unsigned long vaddr(struct vscsibk_pend *req, int seg)
 257{
 258        return vaddr_page(req->pages[seg]);
 259}
 260
 261static void scsiback_print_status(char *sense_buffer, int errors,
 262                                        struct vscsibk_pend *pending_req)
 263{
 264        struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 265
 266        pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
 267               tpg->tport->tport_name, pending_req->v2p->lun,
 268               pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
 269               host_byte(errors), driver_byte(errors));
 270}
 271
 272static void scsiback_fast_flush_area(struct vscsibk_pend *req)
 273{
 274        struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
 275        struct page *pages[VSCSI_GRANT_BATCH];
 276        unsigned int i, invcount = 0;
 277        grant_handle_t handle;
 278        int err;
 279
 280        kfree(req->sgl);
 281        req->sgl = NULL;
 282        req->n_sg = 0;
 283
 284        if (!req->n_grants)
 285                return;
 286
 287        for (i = 0; i < req->n_grants; i++) {
 288                handle = req->grant_handles[i];
 289                if (handle == SCSIBACK_INVALID_HANDLE)
 290                        continue;
 291                gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
 292                                    GNTMAP_host_map, handle);
 293                req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 294                pages[invcount] = req->pages[i];
 295                put_page(pages[invcount]);
 296                invcount++;
 297                if (invcount < VSCSI_GRANT_BATCH)
 298                        continue;
 299                err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 300                BUG_ON(err);
 301                invcount = 0;
 302        }
 303
 304        if (invcount) {
 305                err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 306                BUG_ON(err);
 307        }
 308
 309        put_free_pages(req->pages, req->n_grants);
 310        req->n_grants = 0;
 311}
 312
 313static void scsiback_free_translation_entry(struct kref *kref)
 314{
 315        struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
 316        struct scsiback_tpg *tpg = entry->tpg;
 317
 318        mutex_lock(&tpg->tv_tpg_mutex);
 319        tpg->tv_tpg_fe_count--;
 320        mutex_unlock(&tpg->tv_tpg_mutex);
 321
 322        kfree(entry);
 323}
 324
 325static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
 326                        uint32_t resid, struct vscsibk_pend *pending_req)
 327{
 328        struct vscsiif_response *ring_res;
 329        struct vscsibk_info *info = pending_req->info;
 330        int notify;
 331        struct scsi_sense_hdr sshdr;
 332        unsigned long flags;
 333        unsigned len;
 334
 335        spin_lock_irqsave(&info->ring_lock, flags);
 336
 337        ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
 338        info->ring.rsp_prod_pvt++;
 339
 340        ring_res->rslt   = result;
 341        ring_res->rqid   = pending_req->rqid;
 342
 343        if (sense_buffer != NULL &&
 344            scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
 345                                 &sshdr)) {
 346                len = min_t(unsigned, 8 + sense_buffer[7],
 347                            VSCSIIF_SENSE_BUFFERSIZE);
 348                memcpy(ring_res->sense_buffer, sense_buffer, len);
 349                ring_res->sense_len = len;
 350        } else {
 351                ring_res->sense_len = 0;
 352        }
 353
 354        ring_res->residual_len = resid;
 355
 356        RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
 357        spin_unlock_irqrestore(&info->ring_lock, flags);
 358
 359        if (notify)
 360                notify_remote_via_irq(info->irq);
 361
 362        if (pending_req->v2p)
 363                kref_put(&pending_req->v2p->kref,
 364                         scsiback_free_translation_entry);
 365}
 366
 367static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
 368{
 369        struct vscsibk_info *info = pending_req->info;
 370        unsigned char *sense_buffer;
 371        unsigned int resid;
 372        int errors;
 373
 374        sense_buffer = pending_req->sense_buffer;
 375        resid        = pending_req->se_cmd.residual_count;
 376        errors       = pending_req->result;
 377
 378        if (errors && log_print_stat)
 379                scsiback_print_status(sense_buffer, errors, pending_req);
 380
 381        scsiback_fast_flush_area(pending_req);
 382        scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
 383        scsiback_put(info);
 384}
 385
 386static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
 387{
 388        struct se_cmd *se_cmd = &pending_req->se_cmd;
 389        struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
 390        int rc;
 391
 392        memset(pending_req->sense_buffer, 0, VSCSIIF_SENSE_BUFFERSIZE);
 393
 394        memset(se_cmd, 0, sizeof(*se_cmd));
 395
 396        scsiback_get(pending_req->info);
 397        se_cmd->tag = pending_req->rqid;
 398        rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,
 399                        pending_req->sense_buffer, pending_req->v2p->lun,
 400                        pending_req->data_len, 0,
 401                        pending_req->sc_data_direction, 0,
 402                        pending_req->sgl, pending_req->n_sg,
 403                        NULL, 0, NULL, 0);
 404        if (rc < 0) {
 405                transport_send_check_condition_and_sense(se_cmd,
 406                                TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
 407                transport_generic_free_cmd(se_cmd, 0);
 408        }
 409}
 410
 411static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 412        struct page **pg, grant_handle_t *grant, int cnt)
 413{
 414        int err, i;
 415
 416        if (!cnt)
 417                return 0;
 418
 419        err = gnttab_map_refs(map, NULL, pg, cnt);
 420        BUG_ON(err);
 421        for (i = 0; i < cnt; i++) {
 422                if (unlikely(map[i].status != GNTST_okay)) {
 423                        pr_err("invalid buffer -- could not remap it\n");
 424                        map[i].handle = SCSIBACK_INVALID_HANDLE;
 425                        err = -ENOMEM;
 426                } else {
 427                        get_page(pg[i]);
 428                }
 429                grant[i] = map[i].handle;
 430        }
 431        return err;
 432}
 433
 434static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
 435                        struct scsiif_request_segment *seg, struct page **pg,
 436                        grant_handle_t *grant, int cnt, u32 flags)
 437{
 438        int mapcount = 0, i, err = 0;
 439        struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
 440        struct vscsibk_info *info = pending_req->info;
 441
 442        for (i = 0; i < cnt; i++) {
 443                if (get_free_page(pg + mapcount)) {
 444                        put_free_pages(pg, mapcount);
 445                        pr_err("no grant page\n");
 446                        return -ENOMEM;
 447                }
 448                gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
 449                                  flags, seg[i].gref, info->domid);
 450                mapcount++;
 451                if (mapcount < VSCSI_GRANT_BATCH)
 452                        continue;
 453                err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 454                pg += mapcount;
 455                grant += mapcount;
 456                pending_req->n_grants += mapcount;
 457                if (err)
 458                        return err;
 459                mapcount = 0;
 460        }
 461        err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 462        pending_req->n_grants += mapcount;
 463        return err;
 464}
 465
 466static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 467                                        struct vscsibk_pend *pending_req)
 468{
 469        u32 flags;
 470        int i, err, n_segs, i_seg = 0;
 471        struct page **pg;
 472        struct scsiif_request_segment *seg;
 473        unsigned long end_seg = 0;
 474        unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
 475        unsigned int nr_sgl = 0;
 476        struct scatterlist *sg;
 477        grant_handle_t *grant;
 478
 479        pending_req->n_sg = 0;
 480        pending_req->n_grants = 0;
 481        pending_req->data_len = 0;
 482
 483        nr_segments &= ~VSCSIIF_SG_GRANT;
 484        if (!nr_segments)
 485                return 0;
 486
 487        if (nr_segments > VSCSIIF_SG_TABLESIZE) {
 488                pr_debug("invalid parameter nr_seg = %d\n",
 489                        ring_req->nr_segments);
 490                return -EINVAL;
 491        }
 492
 493        if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
 494                err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
 495                        pending_req->pages, pending_req->grant_handles,
 496                        nr_segments, GNTMAP_host_map | GNTMAP_readonly);
 497                if (err)
 498                        return err;
 499                nr_sgl = nr_segments;
 500                nr_segments = 0;
 501                for (i = 0; i < nr_sgl; i++) {
 502                        n_segs = ring_req->seg[i].length /
 503                                 sizeof(struct scsiif_request_segment);
 504                        if ((unsigned)ring_req->seg[i].offset +
 505                            (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
 506                            n_segs * sizeof(struct scsiif_request_segment) !=
 507                            ring_req->seg[i].length)
 508                                return -EINVAL;
 509                        nr_segments += n_segs;
 510                }
 511                if (nr_segments > SG_ALL) {
 512                        pr_debug("invalid nr_seg = %d\n", nr_segments);
 513                        return -EINVAL;
 514                }
 515        }
 516
 517        /* free of (sgl) in fast_flush_area() */
 518        pending_req->sgl = kmalloc_array(nr_segments,
 519                                        sizeof(struct scatterlist), GFP_KERNEL);
 520        if (!pending_req->sgl)
 521                return -ENOMEM;
 522
 523        sg_init_table(pending_req->sgl, nr_segments);
 524        pending_req->n_sg = nr_segments;
 525
 526        flags = GNTMAP_host_map;
 527        if (pending_req->sc_data_direction == DMA_TO_DEVICE)
 528                flags |= GNTMAP_readonly;
 529
 530        pg = pending_req->pages + nr_sgl;
 531        grant = pending_req->grant_handles + nr_sgl;
 532        if (!nr_sgl) {
 533                seg = ring_req->seg;
 534                err = scsiback_gnttab_data_map_list(pending_req, seg,
 535                        pg, grant, nr_segments, flags);
 536                if (err)
 537                        return err;
 538        } else {
 539                for (i = 0; i < nr_sgl; i++) {
 540                        seg = (struct scsiif_request_segment *)(
 541                              vaddr(pending_req, i) + ring_req->seg[i].offset);
 542                        n_segs = ring_req->seg[i].length /
 543                                 sizeof(struct scsiif_request_segment);
 544                        err = scsiback_gnttab_data_map_list(pending_req, seg,
 545                                pg, grant, n_segs, flags);
 546                        if (err)
 547                                return err;
 548                        pg += n_segs;
 549                        grant += n_segs;
 550                }
 551                end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
 552                seg = (struct scsiif_request_segment *)end_seg;
 553                end_seg += ring_req->seg[0].length;
 554                pg = pending_req->pages + nr_sgl;
 555        }
 556
 557        for_each_sg(pending_req->sgl, sg, nr_segments, i) {
 558                sg_set_page(sg, pg[i], seg->length, seg->offset);
 559                pending_req->data_len += seg->length;
 560                seg++;
 561                if (nr_sgl && (unsigned long)seg >= end_seg) {
 562                        i_seg++;
 563                        end_seg = vaddr(pending_req, i_seg) +
 564                                  ring_req->seg[i_seg].offset;
 565                        seg = (struct scsiif_request_segment *)end_seg;
 566                        end_seg += ring_req->seg[i_seg].length;
 567                }
 568                if (sg->offset >= PAGE_SIZE ||
 569                    sg->length > PAGE_SIZE ||
 570                    sg->offset + sg->length > PAGE_SIZE)
 571                        return -EINVAL;
 572        }
 573
 574        return 0;
 575}
 576
 577static void scsiback_disconnect(struct vscsibk_info *info)
 578{
 579        wait_event(info->waiting_to_free,
 580                atomic_read(&info->nr_unreplied_reqs) == 0);
 581
 582        unbind_from_irqhandler(info->irq, info);
 583        info->irq = 0;
 584        xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
 585}
 586
 587static void scsiback_device_action(struct vscsibk_pend *pending_req,
 588        enum tcm_tmreq_table act, int tag)
 589{
 590        int rc, err = FAILED;
 591        struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 592        struct se_cmd *se_cmd = &pending_req->se_cmd;
 593        struct scsiback_tmr *tmr;
 594
 595        tmr = kzalloc(sizeof(struct scsiback_tmr), GFP_KERNEL);
 596        if (!tmr)
 597                goto out;
 598
 599        init_waitqueue_head(&tmr->tmr_wait);
 600
 601        transport_init_se_cmd(se_cmd, tpg->se_tpg.se_tpg_tfo,
 602                tpg->tpg_nexus->tvn_se_sess, 0, DMA_NONE, TCM_SIMPLE_TAG,
 603                &pending_req->sense_buffer[0]);
 604
 605        rc = core_tmr_alloc_req(se_cmd, tmr, act, GFP_KERNEL);
 606        if (rc < 0)
 607                goto out;
 608
 609        se_cmd->se_tmr_req->ref_task_tag = tag;
 610
 611        if (transport_lookup_tmr_lun(se_cmd, pending_req->v2p->lun) < 0)
 612                goto out;
 613
 614        transport_generic_handle_tmr(se_cmd);
 615        wait_event(tmr->tmr_wait, atomic_read(&tmr->tmr_complete));
 616
 617        err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
 618                SUCCESS : FAILED;
 619
 620out:
 621        if (tmr) {
 622                transport_generic_free_cmd(&pending_req->se_cmd, 1);
 623                kfree(tmr);
 624        }
 625
 626        scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 627
 628        kmem_cache_free(scsiback_cachep, pending_req);
 629}
 630
 631/*
 632  Perform virtual to physical translation
 633*/
 634static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
 635                        struct ids_tuple *v)
 636{
 637        struct v2p_entry *entry;
 638        struct list_head *head = &(info->v2p_entry_lists);
 639        unsigned long flags;
 640
 641        spin_lock_irqsave(&info->v2p_lock, flags);
 642        list_for_each_entry(entry, head, l) {
 643                if ((entry->v.chn == v->chn) &&
 644                    (entry->v.tgt == v->tgt) &&
 645                    (entry->v.lun == v->lun)) {
 646                        kref_get(&entry->kref);
 647                        goto out;
 648                }
 649        }
 650        entry = NULL;
 651
 652out:
 653        spin_unlock_irqrestore(&info->v2p_lock, flags);
 654        return entry;
 655}
 656
 657static int prepare_pending_reqs(struct vscsibk_info *info,
 658                                struct vscsiif_request *ring_req,
 659                                struct vscsibk_pend *pending_req)
 660{
 661        struct v2p_entry *v2p;
 662        struct ids_tuple vir;
 663
 664        pending_req->rqid       = ring_req->rqid;
 665        pending_req->info       = info;
 666
 667        vir.chn = ring_req->channel;
 668        vir.tgt = ring_req->id;
 669        vir.lun = ring_req->lun;
 670
 671        v2p = scsiback_do_translation(info, &vir);
 672        if (!v2p) {
 673                pending_req->v2p = NULL;
 674                pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
 675                        vir.chn, vir.tgt, vir.lun);
 676                return -ENODEV;
 677        }
 678        pending_req->v2p = v2p;
 679
 680        /* request range check from frontend */
 681        pending_req->sc_data_direction = ring_req->sc_data_direction;
 682        if ((pending_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
 683                (pending_req->sc_data_direction != DMA_TO_DEVICE) &&
 684                (pending_req->sc_data_direction != DMA_FROM_DEVICE) &&
 685                (pending_req->sc_data_direction != DMA_NONE)) {
 686                pr_debug("invalid parameter data_dir = %d\n",
 687                        pending_req->sc_data_direction);
 688                return -EINVAL;
 689        }
 690
 691        pending_req->cmd_len = ring_req->cmd_len;
 692        if (pending_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
 693                pr_debug("invalid parameter cmd_len = %d\n",
 694                        pending_req->cmd_len);
 695                return -EINVAL;
 696        }
 697        memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
 698
 699        return 0;
 700}
 701
 702static int scsiback_do_cmd_fn(struct vscsibk_info *info)
 703{
 704        struct vscsiif_back_ring *ring = &info->ring;
 705        struct vscsiif_request ring_req;
 706        struct vscsibk_pend *pending_req;
 707        RING_IDX rc, rp;
 708        int err, more_to_do;
 709        uint32_t result;
 710
 711        rc = ring->req_cons;
 712        rp = ring->sring->req_prod;
 713        rmb();  /* guest system is accessing ring, too */
 714
 715        if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
 716                rc = ring->rsp_prod_pvt;
 717                pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 718                           info->domid, rp, rc, rp - rc);
 719                info->ring_error = 1;
 720                return 0;
 721        }
 722
 723        while ((rc != rp)) {
 724                if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
 725                        break;
 726                pending_req = kmem_cache_alloc(scsiback_cachep, GFP_KERNEL);
 727                if (!pending_req)
 728                        return 1;
 729
 730                ring_req = *RING_GET_REQUEST(ring, rc);
 731                ring->req_cons = ++rc;
 732
 733                err = prepare_pending_reqs(info, &ring_req, pending_req);
 734                if (err) {
 735                        switch (err) {
 736                        case -ENODEV:
 737                                result = DID_NO_CONNECT;
 738                                break;
 739                        default:
 740                                result = DRIVER_ERROR;
 741                                break;
 742                        }
 743                        scsiback_do_resp_with_sense(NULL, result << 24, 0,
 744                                                    pending_req);
 745                        kmem_cache_free(scsiback_cachep, pending_req);
 746                        return 1;
 747                }
 748
 749                switch (ring_req.act) {
 750                case VSCSIIF_ACT_SCSI_CDB:
 751                        if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
 752                                scsiback_fast_flush_area(pending_req);
 753                                scsiback_do_resp_with_sense(NULL,
 754                                        DRIVER_ERROR << 24, 0, pending_req);
 755                                kmem_cache_free(scsiback_cachep, pending_req);
 756                        } else {
 757                                scsiback_cmd_exec(pending_req);
 758                        }
 759                        break;
 760                case VSCSIIF_ACT_SCSI_ABORT:
 761                        scsiback_device_action(pending_req, TMR_ABORT_TASK,
 762                                ring_req.ref_rqid);
 763                        break;
 764                case VSCSIIF_ACT_SCSI_RESET:
 765                        scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
 766                        break;
 767                default:
 768                        pr_err_ratelimited("invalid request\n");
 769                        scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24,
 770                                                    0, pending_req);
 771                        kmem_cache_free(scsiback_cachep, pending_req);
 772                        break;
 773                }
 774
 775                /* Yield point for this unbounded loop. */
 776                cond_resched();
 777        }
 778
 779        RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
 780        return more_to_do;
 781}
 782
 783static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
 784{
 785        struct vscsibk_info *info = dev_id;
 786
 787        if (info->ring_error)
 788                return IRQ_HANDLED;
 789
 790        while (scsiback_do_cmd_fn(info))
 791                cond_resched();
 792
 793        return IRQ_HANDLED;
 794}
 795
 796static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 797                        evtchn_port_t evtchn)
 798{
 799        void *area;
 800        struct vscsiif_sring *sring;
 801        int err;
 802
 803        if (info->irq)
 804                return -1;
 805
 806        err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 807        if (err)
 808                return err;
 809
 810        sring = (struct vscsiif_sring *)area;
 811        BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 812
 813        err = bind_interdomain_evtchn_to_irq(info->domid, evtchn);
 814        if (err < 0)
 815                goto unmap_page;
 816
 817        info->irq = err;
 818
 819        err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
 820                                   IRQF_ONESHOT, "vscsiif-backend", info);
 821        if (err)
 822                goto free_irq;
 823
 824        return 0;
 825
 826free_irq:
 827        unbind_from_irqhandler(info->irq, info);
 828        info->irq = 0;
 829unmap_page:
 830        xenbus_unmap_ring_vfree(info->dev, area);
 831
 832        return err;
 833}
 834
 835static int scsiback_map(struct vscsibk_info *info)
 836{
 837        struct xenbus_device *dev = info->dev;
 838        unsigned int ring_ref, evtchn;
 839        int err;
 840
 841        err = xenbus_gather(XBT_NIL, dev->otherend,
 842                        "ring-ref", "%u", &ring_ref,
 843                        "event-channel", "%u", &evtchn, NULL);
 844        if (err) {
 845                xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
 846                return err;
 847        }
 848
 849        return scsiback_init_sring(info, ring_ref, evtchn);
 850}
 851
 852/*
 853  Add a new translation entry
 854*/
 855static int scsiback_add_translation_entry(struct vscsibk_info *info,
 856                                          char *phy, struct ids_tuple *v)
 857{
 858        int err = 0;
 859        struct v2p_entry *entry;
 860        struct v2p_entry *new;
 861        struct list_head *head = &(info->v2p_entry_lists);
 862        unsigned long flags;
 863        char *lunp;
 864        unsigned long long unpacked_lun;
 865        struct se_lun *se_lun;
 866        struct scsiback_tpg *tpg_entry, *tpg = NULL;
 867        char *error = "doesn't exist";
 868
 869        lunp = strrchr(phy, ':');
 870        if (!lunp) {
 871                pr_err("illegal format of physical device %s\n", phy);
 872                return -EINVAL;
 873        }
 874        *lunp = 0;
 875        lunp++;
 876        err = kstrtoull(lunp, 10, &unpacked_lun);
 877        if (err < 0) {
 878                pr_err("lun number not valid: %s\n", lunp);
 879                return err;
 880        }
 881
 882        mutex_lock(&scsiback_mutex);
 883        list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
 884                if (!strcmp(phy, tpg_entry->tport->tport_name) ||
 885                    !strcmp(phy, tpg_entry->param_alias)) {
 886                        mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
 887                        hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
 888                                if (se_lun->unpacked_lun == unpacked_lun) {
 889                                        if (!tpg_entry->tpg_nexus)
 890                                                error = "nexus undefined";
 891                                        else
 892                                                tpg = tpg_entry;
 893                                        break;
 894                                }
 895                        }
 896                        mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
 897                        break;
 898                }
 899        }
 900        if (tpg) {
 901                mutex_lock(&tpg->tv_tpg_mutex);
 902                tpg->tv_tpg_fe_count++;
 903                mutex_unlock(&tpg->tv_tpg_mutex);
 904        }
 905        mutex_unlock(&scsiback_mutex);
 906
 907        if (!tpg) {
 908                pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
 909                return -ENODEV;
 910        }
 911
 912        new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
 913        if (new == NULL) {
 914                err = -ENOMEM;
 915                goto out_free;
 916        }
 917
 918        spin_lock_irqsave(&info->v2p_lock, flags);
 919
 920        /* Check double assignment to identical virtual ID */
 921        list_for_each_entry(entry, head, l) {
 922                if ((entry->v.chn == v->chn) &&
 923                    (entry->v.tgt == v->tgt) &&
 924                    (entry->v.lun == v->lun)) {
 925                        pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 926                        err = -EEXIST;
 927                        goto out;
 928                }
 929
 930        }
 931
 932        /* Create a new translation entry and add to the list */
 933        kref_init(&new->kref);
 934        new->v = *v;
 935        new->tpg = tpg;
 936        new->lun = unpacked_lun;
 937        list_add_tail(&new->l, head);
 938
 939out:
 940        spin_unlock_irqrestore(&info->v2p_lock, flags);
 941
 942out_free:
 943        mutex_lock(&tpg->tv_tpg_mutex);
 944        tpg->tv_tpg_fe_count--;
 945        mutex_unlock(&tpg->tv_tpg_mutex);
 946
 947        if (err)
 948                kfree(new);
 949
 950        return err;
 951}
 952
 953static void __scsiback_del_translation_entry(struct v2p_entry *entry)
 954{
 955        list_del(&entry->l);
 956        kref_put(&entry->kref, scsiback_free_translation_entry);
 957}
 958
 959/*
 960  Delete the translation entry specfied
 961*/
 962static int scsiback_del_translation_entry(struct vscsibk_info *info,
 963                                          struct ids_tuple *v)
 964{
 965        struct v2p_entry *entry;
 966        struct list_head *head = &(info->v2p_entry_lists);
 967        unsigned long flags;
 968
 969        spin_lock_irqsave(&info->v2p_lock, flags);
 970        /* Find out the translation entry specified */
 971        list_for_each_entry(entry, head, l) {
 972                if ((entry->v.chn == v->chn) &&
 973                    (entry->v.tgt == v->tgt) &&
 974                    (entry->v.lun == v->lun)) {
 975                        goto found;
 976                }
 977        }
 978
 979        spin_unlock_irqrestore(&info->v2p_lock, flags);
 980        return 1;
 981
 982found:
 983        /* Delete the translation entry specfied */
 984        __scsiback_del_translation_entry(entry);
 985
 986        spin_unlock_irqrestore(&info->v2p_lock, flags);
 987        return 0;
 988}
 989
 990static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
 991                                char *phy, struct ids_tuple *vir, int try)
 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                xenbus_printf(XBT_NIL, info->dev->nodename, state,
1001                              "%d", XenbusStateClosed);
1002        }
1003}
1004
1005static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1006                                struct ids_tuple *vir)
1007{
1008        if (!scsiback_del_translation_entry(info, vir)) {
1009                if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1010                                  "%d", XenbusStateClosed))
1011                        pr_err("xenbus_printf error %s\n", state);
1012        }
1013}
1014
1015#define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1016#define VSCSIBACK_OP_UPDATEDEV_STATE    2
1017
1018static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1019                                     char *ent)
1020{
1021        int err;
1022        struct ids_tuple vir;
1023        char *val;
1024        int device_state;
1025        char phy[VSCSI_NAMELEN];
1026        char str[64];
1027        char state[64];
1028        struct xenbus_device *dev = info->dev;
1029
1030        /* read status */
1031        snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1032        err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1033        if (XENBUS_EXIST_ERR(err))
1034                return;
1035
1036        /* physical SCSI device */
1037        snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1038        val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1039        if (IS_ERR(val)) {
1040                xenbus_printf(XBT_NIL, dev->nodename, state,
1041                              "%d", XenbusStateClosed);
1042                return;
1043        }
1044        strlcpy(phy, val, VSCSI_NAMELEN);
1045        kfree(val);
1046
1047        /* virtual SCSI device */
1048        snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1049        err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1050                           &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1051        if (XENBUS_EXIST_ERR(err)) {
1052                xenbus_printf(XBT_NIL, dev->nodename, state,
1053                              "%d", XenbusStateClosed);
1054                return;
1055        }
1056
1057        switch (op) {
1058        case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1059                switch (device_state) {
1060                case XenbusStateInitialising:
1061                        scsiback_do_add_lun(info, state, phy, &vir, 0);
1062                        break;
1063                case XenbusStateConnected:
1064                        scsiback_do_add_lun(info, state, phy, &vir, 1);
1065                        break;
1066                case XenbusStateClosing:
1067                        scsiback_do_del_lun(info, state, &vir);
1068                        break;
1069                default:
1070                        break;
1071                }
1072                break;
1073
1074        case VSCSIBACK_OP_UPDATEDEV_STATE:
1075                if (device_state == XenbusStateInitialised) {
1076                        /* modify vscsi-devs/dev-x/state */
1077                        if (xenbus_printf(XBT_NIL, dev->nodename, state,
1078                                          "%d", XenbusStateConnected)) {
1079                                pr_err("xenbus_printf error %s\n", str);
1080                                scsiback_del_translation_entry(info, &vir);
1081                                xenbus_printf(XBT_NIL, dev->nodename, state,
1082                                              "%d", XenbusStateClosed);
1083                        }
1084                }
1085                break;
1086        /* When it is necessary, processing is added here. */
1087        default:
1088                break;
1089        }
1090}
1091
1092static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1093{
1094        int i;
1095        char **dir;
1096        unsigned int ndir = 0;
1097
1098        dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1099                               &ndir);
1100        if (IS_ERR(dir))
1101                return;
1102
1103        for (i = 0; i < ndir; i++)
1104                scsiback_do_1lun_hotplug(info, op, dir[i]);
1105
1106        kfree(dir);
1107}
1108
1109static void scsiback_frontend_changed(struct xenbus_device *dev,
1110                                        enum xenbus_state frontend_state)
1111{
1112        struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1113
1114        switch (frontend_state) {
1115        case XenbusStateInitialising:
1116                break;
1117
1118        case XenbusStateInitialised:
1119                if (scsiback_map(info))
1120                        break;
1121
1122                scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1123                xenbus_switch_state(dev, XenbusStateConnected);
1124                break;
1125
1126        case XenbusStateConnected:
1127                scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1128
1129                if (dev->state == XenbusStateConnected)
1130                        break;
1131
1132                xenbus_switch_state(dev, XenbusStateConnected);
1133                break;
1134
1135        case XenbusStateClosing:
1136                if (info->irq)
1137                        scsiback_disconnect(info);
1138
1139                xenbus_switch_state(dev, XenbusStateClosing);
1140                break;
1141
1142        case XenbusStateClosed:
1143                xenbus_switch_state(dev, XenbusStateClosed);
1144                if (xenbus_dev_is_online(dev))
1145                        break;
1146                /* fall through if not online */
1147        case XenbusStateUnknown:
1148                device_unregister(&dev->dev);
1149                break;
1150
1151        case XenbusStateReconfiguring:
1152                scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1153                xenbus_switch_state(dev, XenbusStateReconfigured);
1154
1155                break;
1156
1157        default:
1158                xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1159                                        frontend_state);
1160                break;
1161        }
1162}
1163
1164/*
1165  Release the translation entry specfied
1166*/
1167static void scsiback_release_translation_entry(struct vscsibk_info *info)
1168{
1169        struct v2p_entry *entry, *tmp;
1170        struct list_head *head = &(info->v2p_entry_lists);
1171        unsigned long flags;
1172
1173        spin_lock_irqsave(&info->v2p_lock, flags);
1174
1175        list_for_each_entry_safe(entry, tmp, head, l)
1176                __scsiback_del_translation_entry(entry);
1177
1178        spin_unlock_irqrestore(&info->v2p_lock, flags);
1179}
1180
1181static int scsiback_remove(struct xenbus_device *dev)
1182{
1183        struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1184
1185        if (info->irq)
1186                scsiback_disconnect(info);
1187
1188        scsiback_release_translation_entry(info);
1189
1190        dev_set_drvdata(&dev->dev, NULL);
1191
1192        return 0;
1193}
1194
1195static int scsiback_probe(struct xenbus_device *dev,
1196                           const struct xenbus_device_id *id)
1197{
1198        int err;
1199
1200        struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1201                                            GFP_KERNEL);
1202
1203        pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1204
1205        if (!info) {
1206                xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1207                return -ENOMEM;
1208        }
1209        info->dev = dev;
1210        dev_set_drvdata(&dev->dev, info);
1211
1212        info->domid = dev->otherend_id;
1213        spin_lock_init(&info->ring_lock);
1214        info->ring_error = 0;
1215        atomic_set(&info->nr_unreplied_reqs, 0);
1216        init_waitqueue_head(&info->waiting_to_free);
1217        info->dev = dev;
1218        info->irq = 0;
1219        INIT_LIST_HEAD(&info->v2p_entry_lists);
1220        spin_lock_init(&info->v2p_lock);
1221
1222        err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1223                            SG_ALL);
1224        if (err)
1225                xenbus_dev_error(dev, err, "writing feature-sg-grant");
1226
1227        err = xenbus_switch_state(dev, XenbusStateInitWait);
1228        if (err)
1229                goto fail;
1230
1231        return 0;
1232
1233fail:
1234        pr_warn("%s failed\n", __func__);
1235        scsiback_remove(dev);
1236
1237        return err;
1238}
1239
1240static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1241{
1242        switch (tport->tport_proto_id) {
1243        case SCSI_PROTOCOL_SAS:
1244                return "SAS";
1245        case SCSI_PROTOCOL_FCP:
1246                return "FCP";
1247        case SCSI_PROTOCOL_ISCSI:
1248                return "iSCSI";
1249        default:
1250                break;
1251        }
1252
1253        return "Unknown";
1254}
1255
1256static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1257{
1258        struct scsiback_tpg *tpg = container_of(se_tpg,
1259                                struct scsiback_tpg, se_tpg);
1260        struct scsiback_tport *tport = tpg->tport;
1261
1262        return &tport->tport_name[0];
1263}
1264
1265static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1266{
1267        struct scsiback_tpg *tpg = container_of(se_tpg,
1268                                struct scsiback_tpg, se_tpg);
1269        return tpg->tport_tpgt;
1270}
1271
1272static struct se_wwn *
1273scsiback_make_tport(struct target_fabric_configfs *tf,
1274                     struct config_group *group,
1275                     const char *name)
1276{
1277        struct scsiback_tport *tport;
1278        char *ptr;
1279        u64 wwpn = 0;
1280        int off = 0;
1281
1282        tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1283        if (!tport)
1284                return ERR_PTR(-ENOMEM);
1285
1286        tport->tport_wwpn = wwpn;
1287        /*
1288         * Determine the emulated Protocol Identifier and Target Port Name
1289         * based on the incoming configfs directory name.
1290         */
1291        ptr = strstr(name, "naa.");
1292        if (ptr) {
1293                tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1294                goto check_len;
1295        }
1296        ptr = strstr(name, "fc.");
1297        if (ptr) {
1298                tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1299                off = 3; /* Skip over "fc." */
1300                goto check_len;
1301        }
1302        ptr = strstr(name, "iqn.");
1303        if (ptr) {
1304                tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1305                goto check_len;
1306        }
1307
1308        pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1309        kfree(tport);
1310        return ERR_PTR(-EINVAL);
1311
1312check_len:
1313        if (strlen(name) >= VSCSI_NAMELEN) {
1314                pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1315                        scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1316                kfree(tport);
1317                return ERR_PTR(-EINVAL);
1318        }
1319        snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1320
1321        pr_debug("Allocated emulated Target %s Address: %s\n",
1322                 scsiback_dump_proto_id(tport), name);
1323
1324        return &tport->tport_wwn;
1325}
1326
1327static void scsiback_drop_tport(struct se_wwn *wwn)
1328{
1329        struct scsiback_tport *tport = container_of(wwn,
1330                                struct scsiback_tport, tport_wwn);
1331
1332        pr_debug("Deallocating emulated Target %s Address: %s\n",
1333                 scsiback_dump_proto_id(tport), tport->tport_name);
1334
1335        kfree(tport);
1336}
1337
1338static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1339{
1340        return 1;
1341}
1342
1343static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1344{
1345        /*
1346         * Do not release struct se_cmd's containing a valid TMR pointer.
1347         * These will be released directly in scsiback_device_action()
1348         * with transport_generic_free_cmd().
1349         */
1350        if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
1351                return 0;
1352
1353        transport_generic_free_cmd(se_cmd, 0);
1354        return 1;
1355}
1356
1357static void scsiback_release_cmd(struct se_cmd *se_cmd)
1358{
1359        struct vscsibk_pend *pending_req = container_of(se_cmd,
1360                                struct vscsibk_pend, se_cmd);
1361
1362        kmem_cache_free(scsiback_cachep, pending_req);
1363}
1364
1365static int scsiback_shutdown_session(struct se_session *se_sess)
1366{
1367        return 0;
1368}
1369
1370static void scsiback_close_session(struct se_session *se_sess)
1371{
1372}
1373
1374static u32 scsiback_sess_get_index(struct se_session *se_sess)
1375{
1376        return 0;
1377}
1378
1379static int scsiback_write_pending(struct se_cmd *se_cmd)
1380{
1381        /* Go ahead and process the write immediately */
1382        target_execute_cmd(se_cmd);
1383
1384        return 0;
1385}
1386
1387static int scsiback_write_pending_status(struct se_cmd *se_cmd)
1388{
1389        return 0;
1390}
1391
1392static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1393{
1394}
1395
1396static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1397{
1398        return 0;
1399}
1400
1401static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1402{
1403        struct vscsibk_pend *pending_req = container_of(se_cmd,
1404                                struct vscsibk_pend, se_cmd);
1405
1406        pending_req->result = SAM_STAT_GOOD;
1407        scsiback_cmd_done(pending_req);
1408        return 0;
1409}
1410
1411static int scsiback_queue_status(struct se_cmd *se_cmd)
1412{
1413        struct vscsibk_pend *pending_req = container_of(se_cmd,
1414                                struct vscsibk_pend, se_cmd);
1415
1416        if (se_cmd->sense_buffer &&
1417            ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1418             (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1419                pending_req->result = (DRIVER_SENSE << 24) |
1420                                      SAM_STAT_CHECK_CONDITION;
1421        else
1422                pending_req->result = se_cmd->scsi_status;
1423
1424        scsiback_cmd_done(pending_req);
1425        return 0;
1426}
1427
1428static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1429{
1430        struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
1431        struct scsiback_tmr *tmr = se_tmr->fabric_tmr_ptr;
1432
1433        atomic_set(&tmr->tmr_complete, 1);
1434        wake_up(&tmr->tmr_wait);
1435}
1436
1437static void scsiback_aborted_task(struct se_cmd *se_cmd)
1438{
1439}
1440
1441static ssize_t scsiback_tpg_param_show_alias(struct se_portal_group *se_tpg,
1442                                             char *page)
1443{
1444        struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1445                                                se_tpg);
1446        ssize_t rb;
1447
1448        mutex_lock(&tpg->tv_tpg_mutex);
1449        rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1450        mutex_unlock(&tpg->tv_tpg_mutex);
1451
1452        return rb;
1453}
1454
1455static ssize_t scsiback_tpg_param_store_alias(struct se_portal_group *se_tpg,
1456                                              const char *page, size_t count)
1457{
1458        struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1459                                                se_tpg);
1460        int len;
1461
1462        if (strlen(page) >= VSCSI_NAMELEN) {
1463                pr_err("param alias: %s, exceeds max: %d\n", page,
1464                        VSCSI_NAMELEN);
1465                return -EINVAL;
1466        }
1467
1468        mutex_lock(&tpg->tv_tpg_mutex);
1469        len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1470        if (tpg->param_alias[len - 1] == '\n')
1471                tpg->param_alias[len - 1] = '\0';
1472        mutex_unlock(&tpg->tv_tpg_mutex);
1473
1474        return count;
1475}
1476
1477TF_TPG_PARAM_ATTR(scsiback, alias, S_IRUGO | S_IWUSR);
1478
1479static struct configfs_attribute *scsiback_param_attrs[] = {
1480        &scsiback_tpg_param_alias.attr,
1481        NULL,
1482};
1483
1484static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1485                                const char *name)
1486{
1487        struct se_portal_group *se_tpg;
1488        struct se_session *se_sess;
1489        struct scsiback_nexus *tv_nexus;
1490
1491        mutex_lock(&tpg->tv_tpg_mutex);
1492        if (tpg->tpg_nexus) {
1493                mutex_unlock(&tpg->tv_tpg_mutex);
1494                pr_debug("tpg->tpg_nexus already exists\n");
1495                return -EEXIST;
1496        }
1497        se_tpg = &tpg->se_tpg;
1498
1499        tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1500        if (!tv_nexus) {
1501                mutex_unlock(&tpg->tv_tpg_mutex);
1502                return -ENOMEM;
1503        }
1504        /*
1505         * Initialize the struct se_session pointer
1506         */
1507        tv_nexus->tvn_se_sess = transport_init_session(TARGET_PROT_NORMAL);
1508        if (IS_ERR(tv_nexus->tvn_se_sess)) {
1509                mutex_unlock(&tpg->tv_tpg_mutex);
1510                kfree(tv_nexus);
1511                return -ENOMEM;
1512        }
1513        se_sess = tv_nexus->tvn_se_sess;
1514        /*
1515         * Since we are running in 'demo mode' this call with generate a
1516         * struct se_node_acl for the scsiback struct se_portal_group with
1517         * the SCSI Initiator port name of the passed configfs group 'name'.
1518         */
1519        tv_nexus->tvn_se_sess->se_node_acl = core_tpg_check_initiator_node_acl(
1520                                se_tpg, (unsigned char *)name);
1521        if (!tv_nexus->tvn_se_sess->se_node_acl) {
1522                mutex_unlock(&tpg->tv_tpg_mutex);
1523                pr_debug("core_tpg_check_initiator_node_acl() failed for %s\n",
1524                         name);
1525                goto out;
1526        }
1527        /* Now register the TCM pvscsi virtual I_T Nexus as active. */
1528        transport_register_session(se_tpg, tv_nexus->tvn_se_sess->se_node_acl,
1529                        tv_nexus->tvn_se_sess, tv_nexus);
1530        tpg->tpg_nexus = tv_nexus;
1531
1532        mutex_unlock(&tpg->tv_tpg_mutex);
1533        return 0;
1534
1535out:
1536        transport_free_session(se_sess);
1537        kfree(tv_nexus);
1538        return -ENOMEM;
1539}
1540
1541static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1542{
1543        struct se_session *se_sess;
1544        struct scsiback_nexus *tv_nexus;
1545
1546        mutex_lock(&tpg->tv_tpg_mutex);
1547        tv_nexus = tpg->tpg_nexus;
1548        if (!tv_nexus) {
1549                mutex_unlock(&tpg->tv_tpg_mutex);
1550                return -ENODEV;
1551        }
1552
1553        se_sess = tv_nexus->tvn_se_sess;
1554        if (!se_sess) {
1555                mutex_unlock(&tpg->tv_tpg_mutex);
1556                return -ENODEV;
1557        }
1558
1559        if (tpg->tv_tpg_port_count != 0) {
1560                mutex_unlock(&tpg->tv_tpg_mutex);
1561                pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1562                        tpg->tv_tpg_port_count);
1563                return -EBUSY;
1564        }
1565
1566        if (tpg->tv_tpg_fe_count != 0) {
1567                mutex_unlock(&tpg->tv_tpg_mutex);
1568                pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1569                        tpg->tv_tpg_fe_count);
1570                return -EBUSY;
1571        }
1572
1573        pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1574                scsiback_dump_proto_id(tpg->tport),
1575                tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1576
1577        /*
1578         * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1579         */
1580        transport_deregister_session(tv_nexus->tvn_se_sess);
1581        tpg->tpg_nexus = NULL;
1582        mutex_unlock(&tpg->tv_tpg_mutex);
1583
1584        kfree(tv_nexus);
1585        return 0;
1586}
1587
1588static ssize_t scsiback_tpg_show_nexus(struct se_portal_group *se_tpg,
1589                                        char *page)
1590{
1591        struct scsiback_tpg *tpg = container_of(se_tpg,
1592                                struct scsiback_tpg, se_tpg);
1593        struct scsiback_nexus *tv_nexus;
1594        ssize_t ret;
1595
1596        mutex_lock(&tpg->tv_tpg_mutex);
1597        tv_nexus = tpg->tpg_nexus;
1598        if (!tv_nexus) {
1599                mutex_unlock(&tpg->tv_tpg_mutex);
1600                return -ENODEV;
1601        }
1602        ret = snprintf(page, PAGE_SIZE, "%s\n",
1603                        tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1604        mutex_unlock(&tpg->tv_tpg_mutex);
1605
1606        return ret;
1607}
1608
1609static ssize_t scsiback_tpg_store_nexus(struct se_portal_group *se_tpg,
1610                                         const char *page,
1611                                         size_t count)
1612{
1613        struct scsiback_tpg *tpg = container_of(se_tpg,
1614                                struct scsiback_tpg, se_tpg);
1615        struct scsiback_tport *tport_wwn = tpg->tport;
1616        unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1617        int ret;
1618        /*
1619         * Shutdown the active I_T nexus if 'NULL' is passed.
1620         */
1621        if (!strncmp(page, "NULL", 4)) {
1622                ret = scsiback_drop_nexus(tpg);
1623                return (!ret) ? count : ret;
1624        }
1625        /*
1626         * Otherwise make sure the passed virtual Initiator port WWN matches
1627         * the fabric protocol_id set in scsiback_make_tport(), and call
1628         * scsiback_make_nexus().
1629         */
1630        if (strlen(page) >= VSCSI_NAMELEN) {
1631                pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1632                        page, VSCSI_NAMELEN);
1633                return -EINVAL;
1634        }
1635        snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1636
1637        ptr = strstr(i_port, "naa.");
1638        if (ptr) {
1639                if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1640                        pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1641                                i_port, scsiback_dump_proto_id(tport_wwn));
1642                        return -EINVAL;
1643                }
1644                port_ptr = &i_port[0];
1645                goto check_newline;
1646        }
1647        ptr = strstr(i_port, "fc.");
1648        if (ptr) {
1649                if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1650                        pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1651                                i_port, scsiback_dump_proto_id(tport_wwn));
1652                        return -EINVAL;
1653                }
1654                port_ptr = &i_port[3]; /* Skip over "fc." */
1655                goto check_newline;
1656        }
1657        ptr = strstr(i_port, "iqn.");
1658        if (ptr) {
1659                if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1660                        pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1661                                i_port, scsiback_dump_proto_id(tport_wwn));
1662                        return -EINVAL;
1663                }
1664                port_ptr = &i_port[0];
1665                goto check_newline;
1666        }
1667        pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1668                i_port);
1669        return -EINVAL;
1670        /*
1671         * Clear any trailing newline for the NAA WWN
1672         */
1673check_newline:
1674        if (i_port[strlen(i_port) - 1] == '\n')
1675                i_port[strlen(i_port) - 1] = '\0';
1676
1677        ret = scsiback_make_nexus(tpg, port_ptr);
1678        if (ret < 0)
1679                return ret;
1680
1681        return count;
1682}
1683
1684TF_TPG_BASE_ATTR(scsiback, nexus, S_IRUGO | S_IWUSR);
1685
1686static struct configfs_attribute *scsiback_tpg_attrs[] = {
1687        &scsiback_tpg_nexus.attr,
1688        NULL,
1689};
1690
1691static ssize_t
1692scsiback_wwn_show_attr_version(struct target_fabric_configfs *tf,
1693                                char *page)
1694{
1695        return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1696                UTS_RELEASE"\n",
1697                VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1698}
1699
1700TF_WWN_ATTR_RO(scsiback, version);
1701
1702static struct configfs_attribute *scsiback_wwn_attrs[] = {
1703        &scsiback_wwn_version.attr,
1704        NULL,
1705};
1706
1707static char *scsiback_get_fabric_name(void)
1708{
1709        return "xen-pvscsi";
1710}
1711
1712static int scsiback_port_link(struct se_portal_group *se_tpg,
1713                               struct se_lun *lun)
1714{
1715        struct scsiback_tpg *tpg = container_of(se_tpg,
1716                                struct scsiback_tpg, se_tpg);
1717
1718        mutex_lock(&tpg->tv_tpg_mutex);
1719        tpg->tv_tpg_port_count++;
1720        mutex_unlock(&tpg->tv_tpg_mutex);
1721
1722        return 0;
1723}
1724
1725static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1726                                  struct se_lun *lun)
1727{
1728        struct scsiback_tpg *tpg = container_of(se_tpg,
1729                                struct scsiback_tpg, se_tpg);
1730
1731        mutex_lock(&tpg->tv_tpg_mutex);
1732        tpg->tv_tpg_port_count--;
1733        mutex_unlock(&tpg->tv_tpg_mutex);
1734}
1735
1736static struct se_portal_group *
1737scsiback_make_tpg(struct se_wwn *wwn,
1738                   struct config_group *group,
1739                   const char *name)
1740{
1741        struct scsiback_tport *tport = container_of(wwn,
1742                        struct scsiback_tport, tport_wwn);
1743
1744        struct scsiback_tpg *tpg;
1745        u16 tpgt;
1746        int ret;
1747
1748        if (strstr(name, "tpgt_") != name)
1749                return ERR_PTR(-EINVAL);
1750        ret = kstrtou16(name + 5, 10, &tpgt);
1751        if (ret)
1752                return ERR_PTR(ret);
1753
1754        tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1755        if (!tpg)
1756                return ERR_PTR(-ENOMEM);
1757
1758        mutex_init(&tpg->tv_tpg_mutex);
1759        INIT_LIST_HEAD(&tpg->tv_tpg_list);
1760        INIT_LIST_HEAD(&tpg->info_list);
1761        tpg->tport = tport;
1762        tpg->tport_tpgt = tpgt;
1763
1764        ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1765        if (ret < 0) {
1766                kfree(tpg);
1767                return NULL;
1768        }
1769        mutex_lock(&scsiback_mutex);
1770        list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1771        mutex_unlock(&scsiback_mutex);
1772
1773        return &tpg->se_tpg;
1774}
1775
1776static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1777{
1778        struct scsiback_tpg *tpg = container_of(se_tpg,
1779                                struct scsiback_tpg, se_tpg);
1780
1781        mutex_lock(&scsiback_mutex);
1782        list_del(&tpg->tv_tpg_list);
1783        mutex_unlock(&scsiback_mutex);
1784        /*
1785         * Release the virtual I_T Nexus for this xen-pvscsi TPG
1786         */
1787        scsiback_drop_nexus(tpg);
1788        /*
1789         * Deregister the se_tpg from TCM.
1790         */
1791        core_tpg_deregister(se_tpg);
1792        kfree(tpg);
1793}
1794
1795static int scsiback_check_true(struct se_portal_group *se_tpg)
1796{
1797        return 1;
1798}
1799
1800static int scsiback_check_false(struct se_portal_group *se_tpg)
1801{
1802        return 0;
1803}
1804
1805static const struct target_core_fabric_ops scsiback_ops = {
1806        .module                         = THIS_MODULE,
1807        .name                           = "xen-pvscsi",
1808        .get_fabric_name                = scsiback_get_fabric_name,
1809        .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1810        .tpg_get_tag                    = scsiback_get_tag,
1811        .tpg_check_demo_mode            = scsiback_check_true,
1812        .tpg_check_demo_mode_cache      = scsiback_check_true,
1813        .tpg_check_demo_mode_write_protect = scsiback_check_false,
1814        .tpg_check_prod_mode_write_protect = scsiback_check_false,
1815        .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1816        .check_stop_free                = scsiback_check_stop_free,
1817        .release_cmd                    = scsiback_release_cmd,
1818        .shutdown_session               = scsiback_shutdown_session,
1819        .close_session                  = scsiback_close_session,
1820        .sess_get_index                 = scsiback_sess_get_index,
1821        .sess_get_initiator_sid         = NULL,
1822        .write_pending                  = scsiback_write_pending,
1823        .write_pending_status           = scsiback_write_pending_status,
1824        .set_default_node_attributes    = scsiback_set_default_node_attrs,
1825        .get_cmd_state                  = scsiback_get_cmd_state,
1826        .queue_data_in                  = scsiback_queue_data_in,
1827        .queue_status                   = scsiback_queue_status,
1828        .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1829        .aborted_task                   = scsiback_aborted_task,
1830        /*
1831         * Setup callers for generic logic in target_core_fabric_configfs.c
1832         */
1833        .fabric_make_wwn                = scsiback_make_tport,
1834        .fabric_drop_wwn                = scsiback_drop_tport,
1835        .fabric_make_tpg                = scsiback_make_tpg,
1836        .fabric_drop_tpg                = scsiback_drop_tpg,
1837        .fabric_post_link               = scsiback_port_link,
1838        .fabric_pre_unlink              = scsiback_port_unlink,
1839
1840        .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1841        .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1842        .tfc_tpg_param_attrs            = scsiback_param_attrs,
1843};
1844
1845static const struct xenbus_device_id scsiback_ids[] = {
1846        { "vscsi" },
1847        { "" }
1848};
1849
1850static struct xenbus_driver scsiback_driver = {
1851        .ids                    = scsiback_ids,
1852        .probe                  = scsiback_probe,
1853        .remove                 = scsiback_remove,
1854        .otherend_changed       = scsiback_frontend_changed
1855};
1856
1857static void scsiback_init_pend(void *p)
1858{
1859        struct vscsibk_pend *pend = p;
1860        int i;
1861
1862        memset(pend, 0, sizeof(*pend));
1863        for (i = 0; i < VSCSI_MAX_GRANTS; i++)
1864                pend->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
1865}
1866
1867static int __init scsiback_init(void)
1868{
1869        int ret;
1870
1871        if (!xen_domain())
1872                return -ENODEV;
1873
1874        pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1875                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1876
1877        scsiback_cachep = kmem_cache_create("vscsiif_cache",
1878                sizeof(struct vscsibk_pend), 0, 0, scsiback_init_pend);
1879        if (!scsiback_cachep)
1880                return -ENOMEM;
1881
1882        ret = xenbus_register_backend(&scsiback_driver);
1883        if (ret)
1884                goto out_cache_destroy;
1885
1886        ret = target_register_template(&scsiback_ops);
1887        if (ret)
1888                goto out_unregister_xenbus;
1889
1890        return 0;
1891
1892out_unregister_xenbus:
1893        xenbus_unregister_driver(&scsiback_driver);
1894out_cache_destroy:
1895        kmem_cache_destroy(scsiback_cachep);
1896        pr_err("%s: error %d\n", __func__, ret);
1897        return ret;
1898}
1899
1900static void __exit scsiback_exit(void)
1901{
1902        struct page *page;
1903
1904        while (free_pages_num) {
1905                if (get_free_page(&page))
1906                        BUG();
1907                gnttab_free_pages(1, &page);
1908        }
1909        target_unregister_template(&scsiback_ops);
1910        xenbus_unregister_driver(&scsiback_driver);
1911        kmem_cache_destroy(scsiback_cachep);
1912}
1913
1914module_init(scsiback_init);
1915module_exit(scsiback_exit);
1916
1917MODULE_DESCRIPTION("Xen SCSI backend driver");
1918MODULE_LICENSE("Dual BSD/GPL");
1919MODULE_ALIAS("xen-backend:vscsi");
1920MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");
1921