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
  57#include <asm/hypervisor.h>
  58
  59#include <xen/xen.h>
  60#include <xen/balloon.h>
  61#include <xen/events.h>
  62#include <xen/xenbus.h>
  63#include <xen/grant_table.h>
  64#include <xen/page.h>
  65
  66#include <xen/interface/grant_table.h>
  67#include <xen/interface/io/vscsiif.h>
  68
  69#define VSCSI_VERSION   "v0.1"
  70#define VSCSI_NAMELEN   32
  71
  72struct ids_tuple {
  73        unsigned int hst;               /* host    */
  74        unsigned int chn;               /* channel */
  75        unsigned int tgt;               /* target  */
  76        unsigned int lun;               /* LUN     */
  77};
  78
  79struct v2p_entry {
  80        struct ids_tuple v;             /* translate from */
  81        struct scsiback_tpg *tpg;       /* translate to   */
  82        unsigned int lun;
  83        struct kref kref;
  84        struct list_head l;
  85};
  86
  87struct vscsibk_info {
  88        struct xenbus_device *dev;
  89
  90        domid_t domid;
  91        unsigned int irq;
  92
  93        struct vscsiif_back_ring ring;
  94
  95        spinlock_t ring_lock;
  96        atomic_t nr_unreplied_reqs;
  97
  98        spinlock_t v2p_lock;
  99        struct list_head v2p_entry_lists;
 100
 101        wait_queue_head_t waiting_to_free;
 102
 103        struct gnttab_page_cache free_pages;
 104};
 105
 106/* theoretical maximum of grants for one request */
 107#define VSCSI_MAX_GRANTS        (SG_ALL + VSCSIIF_SG_TABLESIZE)
 108
 109/*
 110 * VSCSI_GRANT_BATCH is the maximum number of grants to be processed in one
 111 * call to map/unmap grants. Don't choose it too large, as there are arrays
 112 * with VSCSI_GRANT_BATCH elements allocated on the stack.
 113 */
 114#define VSCSI_GRANT_BATCH       16
 115
 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        struct completion tmr_done;
 140};
 141
 142#define VSCSI_DEFAULT_SESSION_TAGS      128
 143
 144struct scsiback_nexus {
 145        /* Pointer to TCM session for I_T Nexus */
 146        struct se_session *tvn_se_sess;
 147};
 148
 149struct scsiback_tport {
 150        /* SCSI protocol the tport is providing */
 151        u8 tport_proto_id;
 152        /* Binary World Wide unique Port Name for pvscsi Target port */
 153        u64 tport_wwpn;
 154        /* ASCII formatted WWPN for pvscsi Target port */
 155        char tport_name[VSCSI_NAMELEN];
 156        /* Returned by scsiback_make_tport() */
 157        struct se_wwn tport_wwn;
 158};
 159
 160struct scsiback_tpg {
 161        /* scsiback port target portal group tag for TCM */
 162        u16 tport_tpgt;
 163        /* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
 164        int tv_tpg_port_count;
 165        /* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
 166        int tv_tpg_fe_count;
 167        /* list for scsiback_list */
 168        struct list_head tv_tpg_list;
 169        /* Used to protect access for tpg_nexus */
 170        struct mutex tv_tpg_mutex;
 171        /* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
 172        struct scsiback_nexus *tpg_nexus;
 173        /* Pointer back to scsiback_tport */
 174        struct scsiback_tport *tport;
 175        /* Returned by scsiback_make_tpg() */
 176        struct se_portal_group se_tpg;
 177        /* alias used in xenstore */
 178        char param_alias[VSCSI_NAMELEN];
 179        /* list of info structures related to this target portal group */
 180        struct list_head info_list;
 181};
 182
 183#define SCSIBACK_INVALID_HANDLE (~0)
 184
 185static bool log_print_stat;
 186module_param(log_print_stat, bool, 0644);
 187
 188static int scsiback_max_buffer_pages = 1024;
 189module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
 190MODULE_PARM_DESC(max_buffer_pages,
 191"Maximum number of free pages to keep in backend buffer");
 192
 193/* Global spinlock to protect scsiback TPG list */
 194static DEFINE_MUTEX(scsiback_mutex);
 195static LIST_HEAD(scsiback_list);
 196
 197static void scsiback_get(struct vscsibk_info *info)
 198{
 199        atomic_inc(&info->nr_unreplied_reqs);
 200}
 201
 202static void scsiback_put(struct vscsibk_info *info)
 203{
 204        if (atomic_dec_and_test(&info->nr_unreplied_reqs))
 205                wake_up(&info->waiting_to_free);
 206}
 207
 208static unsigned long vaddr_page(struct page *page)
 209{
 210        unsigned long pfn = page_to_pfn(page);
 211
 212        return (unsigned long)pfn_to_kaddr(pfn);
 213}
 214
 215static unsigned long vaddr(struct vscsibk_pend *req, int seg)
 216{
 217        return vaddr_page(req->pages[seg]);
 218}
 219
 220static void scsiback_print_status(char *sense_buffer, int errors,
 221                                        struct vscsibk_pend *pending_req)
 222{
 223        struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 224
 225        pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
 226               tpg->tport->tport_name, pending_req->v2p->lun,
 227               pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
 228               host_byte(errors), driver_byte(errors));
 229}
 230
 231static void scsiback_fast_flush_area(struct vscsibk_pend *req)
 232{
 233        struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
 234        struct page *pages[VSCSI_GRANT_BATCH];
 235        unsigned int i, invcount = 0;
 236        grant_handle_t handle;
 237        int err;
 238
 239        kfree(req->sgl);
 240        req->sgl = NULL;
 241        req->n_sg = 0;
 242
 243        if (!req->n_grants)
 244                return;
 245
 246        for (i = 0; i < req->n_grants; i++) {
 247                handle = req->grant_handles[i];
 248                if (handle == SCSIBACK_INVALID_HANDLE)
 249                        continue;
 250                gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
 251                                    GNTMAP_host_map, handle);
 252                req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 253                pages[invcount] = req->pages[i];
 254                put_page(pages[invcount]);
 255                invcount++;
 256                if (invcount < VSCSI_GRANT_BATCH)
 257                        continue;
 258                err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 259                BUG_ON(err);
 260                invcount = 0;
 261        }
 262
 263        if (invcount) {
 264                err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 265                BUG_ON(err);
 266        }
 267
 268        gnttab_page_cache_put(&req->info->free_pages, req->pages,
 269                              req->n_grants);
 270        req->n_grants = 0;
 271}
 272
 273static void scsiback_free_translation_entry(struct kref *kref)
 274{
 275        struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
 276        struct scsiback_tpg *tpg = entry->tpg;
 277
 278        mutex_lock(&tpg->tv_tpg_mutex);
 279        tpg->tv_tpg_fe_count--;
 280        mutex_unlock(&tpg->tv_tpg_mutex);
 281
 282        kfree(entry);
 283}
 284
 285static void scsiback_send_response(struct vscsibk_info *info,
 286                        char *sense_buffer, int32_t result, uint32_t resid,
 287                        uint16_t rqid)
 288{
 289        struct vscsiif_response *ring_res;
 290        int notify;
 291        struct scsi_sense_hdr sshdr;
 292        unsigned long flags;
 293        unsigned len;
 294
 295        spin_lock_irqsave(&info->ring_lock, flags);
 296
 297        ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
 298        info->ring.rsp_prod_pvt++;
 299
 300        ring_res->rslt   = result;
 301        ring_res->rqid   = rqid;
 302
 303        if (sense_buffer != NULL &&
 304            scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
 305                                 &sshdr)) {
 306                len = min_t(unsigned, 8 + sense_buffer[7],
 307                            VSCSIIF_SENSE_BUFFERSIZE);
 308                memcpy(ring_res->sense_buffer, sense_buffer, len);
 309                ring_res->sense_len = len;
 310        } else {
 311                ring_res->sense_len = 0;
 312        }
 313
 314        ring_res->residual_len = resid;
 315
 316        RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
 317        spin_unlock_irqrestore(&info->ring_lock, flags);
 318
 319        if (notify)
 320                notify_remote_via_irq(info->irq);
 321}
 322
 323static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
 324                        uint32_t resid, struct vscsibk_pend *pending_req)
 325{
 326        scsiback_send_response(pending_req->info, sense_buffer, result,
 327                               resid, pending_req->rqid);
 328
 329        if (pending_req->v2p)
 330                kref_put(&pending_req->v2p->kref,
 331                         scsiback_free_translation_entry);
 332}
 333
 334static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
 335{
 336        struct vscsibk_info *info = pending_req->info;
 337        unsigned char *sense_buffer;
 338        unsigned int resid;
 339        int errors;
 340
 341        sense_buffer = pending_req->sense_buffer;
 342        resid        = pending_req->se_cmd.residual_count;
 343        errors       = pending_req->result;
 344
 345        if (errors && log_print_stat)
 346                scsiback_print_status(sense_buffer, errors, pending_req);
 347
 348        scsiback_fast_flush_area(pending_req);
 349        scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
 350        scsiback_put(info);
 351        /*
 352         * Drop the extra KREF_ACK reference taken by target_submit_cmd_map_sgls()
 353         * ahead of scsiback_check_stop_free() ->  transport_generic_free_cmd()
 354         * final se_cmd->cmd_kref put.
 355         */
 356        target_put_sess_cmd(&pending_req->se_cmd);
 357}
 358
 359static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
 360{
 361        struct se_cmd *se_cmd = &pending_req->se_cmd;
 362        struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
 363        int rc;
 364
 365        scsiback_get(pending_req->info);
 366        se_cmd->tag = pending_req->rqid;
 367        rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,
 368                        pending_req->sense_buffer, pending_req->v2p->lun,
 369                        pending_req->data_len, 0,
 370                        pending_req->sc_data_direction, TARGET_SCF_ACK_KREF,
 371                        pending_req->sgl, pending_req->n_sg,
 372                        NULL, 0, NULL, 0);
 373        if (rc < 0) {
 374                transport_send_check_condition_and_sense(se_cmd,
 375                                TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
 376                transport_generic_free_cmd(se_cmd, 0);
 377        }
 378}
 379
 380static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 381        struct page **pg, grant_handle_t *grant, int cnt)
 382{
 383        int err, i;
 384
 385        if (!cnt)
 386                return 0;
 387
 388        err = gnttab_map_refs(map, NULL, pg, cnt);
 389        for (i = 0; i < cnt; i++) {
 390                if (unlikely(map[i].status != GNTST_okay)) {
 391                        pr_err("invalid buffer -- could not remap it\n");
 392                        map[i].handle = SCSIBACK_INVALID_HANDLE;
 393                        if (!err)
 394                                err = -ENOMEM;
 395                } else {
 396                        get_page(pg[i]);
 397                }
 398                grant[i] = map[i].handle;
 399        }
 400        return err;
 401}
 402
 403static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
 404                        struct scsiif_request_segment *seg, struct page **pg,
 405                        grant_handle_t *grant, int cnt, u32 flags)
 406{
 407        int mapcount = 0, i, err = 0;
 408        struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
 409        struct vscsibk_info *info = pending_req->info;
 410
 411        for (i = 0; i < cnt; i++) {
 412                if (gnttab_page_cache_get(&info->free_pages, pg + mapcount)) {
 413                        gnttab_page_cache_put(&info->free_pages, pg, mapcount);
 414                        pr_err("no grant page\n");
 415                        return -ENOMEM;
 416                }
 417                gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
 418                                  flags, seg[i].gref, info->domid);
 419                mapcount++;
 420                if (mapcount < VSCSI_GRANT_BATCH)
 421                        continue;
 422                err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 423                pg += mapcount;
 424                grant += mapcount;
 425                pending_req->n_grants += mapcount;
 426                if (err)
 427                        return err;
 428                mapcount = 0;
 429        }
 430        err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 431        pending_req->n_grants += mapcount;
 432        return err;
 433}
 434
 435static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 436                                        struct vscsibk_pend *pending_req)
 437{
 438        u32 flags;
 439        int i, err, n_segs, i_seg = 0;
 440        struct page **pg;
 441        struct scsiif_request_segment *seg;
 442        unsigned long end_seg = 0;
 443        unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
 444        unsigned int nr_sgl = 0;
 445        struct scatterlist *sg;
 446        grant_handle_t *grant;
 447
 448        pending_req->n_sg = 0;
 449        pending_req->n_grants = 0;
 450        pending_req->data_len = 0;
 451
 452        nr_segments &= ~VSCSIIF_SG_GRANT;
 453        if (!nr_segments)
 454                return 0;
 455
 456        if (nr_segments > VSCSIIF_SG_TABLESIZE) {
 457                pr_debug("invalid parameter nr_seg = %d\n",
 458                        ring_req->nr_segments);
 459                return -EINVAL;
 460        }
 461
 462        if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
 463                err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
 464                        pending_req->pages, pending_req->grant_handles,
 465                        nr_segments, GNTMAP_host_map | GNTMAP_readonly);
 466                if (err)
 467                        return err;
 468                nr_sgl = nr_segments;
 469                nr_segments = 0;
 470                for (i = 0; i < nr_sgl; i++) {
 471                        n_segs = ring_req->seg[i].length /
 472                                 sizeof(struct scsiif_request_segment);
 473                        if ((unsigned)ring_req->seg[i].offset +
 474                            (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
 475                            n_segs * sizeof(struct scsiif_request_segment) !=
 476                            ring_req->seg[i].length)
 477                                return -EINVAL;
 478                        nr_segments += n_segs;
 479                }
 480                if (nr_segments > SG_ALL) {
 481                        pr_debug("invalid nr_seg = %d\n", nr_segments);
 482                        return -EINVAL;
 483                }
 484        }
 485
 486        /* free of (sgl) in fast_flush_area() */
 487        pending_req->sgl = kmalloc_array(nr_segments,
 488                                        sizeof(struct scatterlist), GFP_KERNEL);
 489        if (!pending_req->sgl)
 490                return -ENOMEM;
 491
 492        sg_init_table(pending_req->sgl, nr_segments);
 493        pending_req->n_sg = nr_segments;
 494
 495        flags = GNTMAP_host_map;
 496        if (pending_req->sc_data_direction == DMA_TO_DEVICE)
 497                flags |= GNTMAP_readonly;
 498
 499        pg = pending_req->pages + nr_sgl;
 500        grant = pending_req->grant_handles + nr_sgl;
 501        if (!nr_sgl) {
 502                seg = ring_req->seg;
 503                err = scsiback_gnttab_data_map_list(pending_req, seg,
 504                        pg, grant, nr_segments, flags);
 505                if (err)
 506                        return err;
 507        } else {
 508                for (i = 0; i < nr_sgl; i++) {
 509                        seg = (struct scsiif_request_segment *)(
 510                              vaddr(pending_req, i) + ring_req->seg[i].offset);
 511                        n_segs = ring_req->seg[i].length /
 512                                 sizeof(struct scsiif_request_segment);
 513                        err = scsiback_gnttab_data_map_list(pending_req, seg,
 514                                pg, grant, n_segs, flags);
 515                        if (err)
 516                                return err;
 517                        pg += n_segs;
 518                        grant += n_segs;
 519                }
 520                end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
 521                seg = (struct scsiif_request_segment *)end_seg;
 522                end_seg += ring_req->seg[0].length;
 523                pg = pending_req->pages + nr_sgl;
 524        }
 525
 526        for_each_sg(pending_req->sgl, sg, nr_segments, i) {
 527                sg_set_page(sg, pg[i], seg->length, seg->offset);
 528                pending_req->data_len += seg->length;
 529                seg++;
 530                if (nr_sgl && (unsigned long)seg >= end_seg) {
 531                        i_seg++;
 532                        end_seg = vaddr(pending_req, i_seg) +
 533                                  ring_req->seg[i_seg].offset;
 534                        seg = (struct scsiif_request_segment *)end_seg;
 535                        end_seg += ring_req->seg[i_seg].length;
 536                }
 537                if (sg->offset >= PAGE_SIZE ||
 538                    sg->length > PAGE_SIZE ||
 539                    sg->offset + sg->length > PAGE_SIZE)
 540                        return -EINVAL;
 541        }
 542
 543        return 0;
 544}
 545
 546static void scsiback_disconnect(struct vscsibk_info *info)
 547{
 548        wait_event(info->waiting_to_free,
 549                atomic_read(&info->nr_unreplied_reqs) == 0);
 550
 551        unbind_from_irqhandler(info->irq, info);
 552        info->irq = 0;
 553        xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
 554}
 555
 556static void scsiback_device_action(struct vscsibk_pend *pending_req,
 557        enum tcm_tmreq_table act, int tag)
 558{
 559        struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 560        struct scsiback_nexus *nexus = tpg->tpg_nexus;
 561        struct se_cmd *se_cmd = &pending_req->se_cmd;
 562        u64 unpacked_lun = pending_req->v2p->lun;
 563        int rc, err = FAILED;
 564
 565        init_completion(&pending_req->tmr_done);
 566
 567        rc = target_submit_tmr(&pending_req->se_cmd, nexus->tvn_se_sess,
 568                               &pending_req->sense_buffer[0],
 569                               unpacked_lun, NULL, act, GFP_KERNEL,
 570                               tag, TARGET_SCF_ACK_KREF);
 571        if (rc)
 572                goto err;
 573
 574        wait_for_completion(&pending_req->tmr_done);
 575
 576        err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
 577                SUCCESS : FAILED;
 578
 579        scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 580        transport_generic_free_cmd(&pending_req->se_cmd, 0);
 581        return;
 582
 583err:
 584        scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 585}
 586
 587/*
 588  Perform virtual to physical translation
 589*/
 590static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
 591                        struct ids_tuple *v)
 592{
 593        struct v2p_entry *entry;
 594        struct list_head *head = &(info->v2p_entry_lists);
 595        unsigned long flags;
 596
 597        spin_lock_irqsave(&info->v2p_lock, flags);
 598        list_for_each_entry(entry, head, l) {
 599                if ((entry->v.chn == v->chn) &&
 600                    (entry->v.tgt == v->tgt) &&
 601                    (entry->v.lun == v->lun)) {
 602                        kref_get(&entry->kref);
 603                        goto out;
 604                }
 605        }
 606        entry = NULL;
 607
 608out:
 609        spin_unlock_irqrestore(&info->v2p_lock, flags);
 610        return entry;
 611}
 612
 613static struct vscsibk_pend *scsiback_get_pend_req(struct vscsiif_back_ring *ring,
 614                                struct v2p_entry *v2p)
 615{
 616        struct scsiback_tpg *tpg = v2p->tpg;
 617        struct scsiback_nexus *nexus = tpg->tpg_nexus;
 618        struct se_session *se_sess = nexus->tvn_se_sess;
 619        struct vscsibk_pend *req;
 620        int tag, cpu, i;
 621
 622        tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
 623        if (tag < 0) {
 624                pr_err("Unable to obtain tag for vscsiif_request\n");
 625                return ERR_PTR(-ENOMEM);
 626        }
 627
 628        req = &((struct vscsibk_pend *)se_sess->sess_cmd_map)[tag];
 629        memset(req, 0, sizeof(*req));
 630        req->se_cmd.map_tag = tag;
 631        req->se_cmd.map_cpu = cpu;
 632
 633        for (i = 0; i < VSCSI_MAX_GRANTS; i++)
 634                req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 635
 636        return req;
 637}
 638
 639static struct vscsibk_pend *prepare_pending_reqs(struct vscsibk_info *info,
 640                                struct vscsiif_back_ring *ring,
 641                                struct vscsiif_request *ring_req)
 642{
 643        struct vscsibk_pend *pending_req;
 644        struct v2p_entry *v2p;
 645        struct ids_tuple vir;
 646
 647        /* request range check from frontend */
 648        if ((ring_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
 649                (ring_req->sc_data_direction != DMA_TO_DEVICE) &&
 650                (ring_req->sc_data_direction != DMA_FROM_DEVICE) &&
 651                (ring_req->sc_data_direction != DMA_NONE)) {
 652                pr_debug("invalid parameter data_dir = %d\n",
 653                        ring_req->sc_data_direction);
 654                return ERR_PTR(-EINVAL);
 655        }
 656        if (ring_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
 657                pr_debug("invalid parameter cmd_len = %d\n",
 658                        ring_req->cmd_len);
 659                return ERR_PTR(-EINVAL);
 660        }
 661
 662        vir.chn = ring_req->channel;
 663        vir.tgt = ring_req->id;
 664        vir.lun = ring_req->lun;
 665
 666        v2p = scsiback_do_translation(info, &vir);
 667        if (!v2p) {
 668                pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
 669                         vir.chn, vir.tgt, vir.lun);
 670                return ERR_PTR(-ENODEV);
 671        }
 672
 673        pending_req = scsiback_get_pend_req(ring, v2p);
 674        if (IS_ERR(pending_req)) {
 675                kref_put(&v2p->kref, scsiback_free_translation_entry);
 676                return ERR_PTR(-ENOMEM);
 677        }
 678        pending_req->rqid = ring_req->rqid;
 679        pending_req->info = info;
 680        pending_req->v2p = v2p;
 681        pending_req->sc_data_direction = ring_req->sc_data_direction;
 682        pending_req->cmd_len = ring_req->cmd_len;
 683        memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
 684
 685        return pending_req;
 686}
 687
 688static int scsiback_do_cmd_fn(struct vscsibk_info *info,
 689                              unsigned int *eoi_flags)
 690{
 691        struct vscsiif_back_ring *ring = &info->ring;
 692        struct vscsiif_request ring_req;
 693        struct vscsibk_pend *pending_req;
 694        RING_IDX rc, rp;
 695        int more_to_do;
 696        uint32_t result;
 697
 698        rc = ring->req_cons;
 699        rp = ring->sring->req_prod;
 700        rmb();  /* guest system is accessing ring, too */
 701
 702        if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
 703                rc = ring->rsp_prod_pvt;
 704                pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 705                           info->domid, rp, rc, rp - rc);
 706                return -EINVAL;
 707        }
 708
 709        while ((rc != rp)) {
 710                *eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS;
 711
 712                if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
 713                        break;
 714
 715                RING_COPY_REQUEST(ring, rc, &ring_req);
 716                ring->req_cons = ++rc;
 717
 718                pending_req = prepare_pending_reqs(info, ring, &ring_req);
 719                if (IS_ERR(pending_req)) {
 720                        switch (PTR_ERR(pending_req)) {
 721                        case -ENODEV:
 722                                result = DID_NO_CONNECT;
 723                                break;
 724                        default:
 725                                result = DRIVER_ERROR;
 726                                break;
 727                        }
 728                        scsiback_send_response(info, NULL, result << 24, 0,
 729                                               ring_req.rqid);
 730                        return 1;
 731                }
 732
 733                switch (ring_req.act) {
 734                case VSCSIIF_ACT_SCSI_CDB:
 735                        if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
 736                                scsiback_fast_flush_area(pending_req);
 737                                scsiback_do_resp_with_sense(NULL,
 738                                                DRIVER_ERROR << 24, 0, pending_req);
 739                                transport_generic_free_cmd(&pending_req->se_cmd, 0);
 740                        } else {
 741                                scsiback_cmd_exec(pending_req);
 742                        }
 743                        break;
 744                case VSCSIIF_ACT_SCSI_ABORT:
 745                        scsiback_device_action(pending_req, TMR_ABORT_TASK,
 746                                ring_req.ref_rqid);
 747                        break;
 748                case VSCSIIF_ACT_SCSI_RESET:
 749                        scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
 750                        break;
 751                default:
 752                        pr_err_ratelimited("invalid request\n");
 753                        scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24, 0,
 754                                                    pending_req);
 755                        transport_generic_free_cmd(&pending_req->se_cmd, 0);
 756                        break;
 757                }
 758
 759                /* Yield point for this unbounded loop. */
 760                cond_resched();
 761        }
 762
 763        gnttab_page_cache_shrink(&info->free_pages, scsiback_max_buffer_pages);
 764
 765        RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
 766        return more_to_do;
 767}
 768
 769static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
 770{
 771        struct vscsibk_info *info = dev_id;
 772        int rc;
 773        unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
 774
 775        while ((rc = scsiback_do_cmd_fn(info, &eoi_flags)) > 0)
 776                cond_resched();
 777
 778        /* In case of a ring error we keep the event channel masked. */
 779        if (!rc)
 780                xen_irq_lateeoi(irq, eoi_flags);
 781
 782        return IRQ_HANDLED;
 783}
 784
 785static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 786                        evtchn_port_t evtchn)
 787{
 788        void *area;
 789        struct vscsiif_sring *sring;
 790        int err;
 791
 792        if (info->irq)
 793                return -1;
 794
 795        err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 796        if (err)
 797                return err;
 798
 799        sring = (struct vscsiif_sring *)area;
 800        BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 801
 802        err = bind_interdomain_evtchn_to_irq_lateeoi(info->dev, evtchn);
 803        if (err < 0)
 804                goto unmap_page;
 805
 806        info->irq = err;
 807
 808        err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
 809                                   IRQF_ONESHOT, "vscsiif-backend", info);
 810        if (err)
 811                goto free_irq;
 812
 813        return 0;
 814
 815free_irq:
 816        unbind_from_irqhandler(info->irq, info);
 817        info->irq = 0;
 818unmap_page:
 819        xenbus_unmap_ring_vfree(info->dev, area);
 820
 821        return err;
 822}
 823
 824static int scsiback_map(struct vscsibk_info *info)
 825{
 826        struct xenbus_device *dev = info->dev;
 827        unsigned int ring_ref;
 828        evtchn_port_t evtchn;
 829        int err;
 830
 831        err = xenbus_gather(XBT_NIL, dev->otherend,
 832                        "ring-ref", "%u", &ring_ref,
 833                        "event-channel", "%u", &evtchn, NULL);
 834        if (err) {
 835                xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
 836                return err;
 837        }
 838
 839        return scsiback_init_sring(info, ring_ref, evtchn);
 840}
 841
 842/*
 843  Check for a translation entry being present
 844*/
 845static struct v2p_entry *scsiback_chk_translation_entry(
 846        struct vscsibk_info *info, struct ids_tuple *v)
 847{
 848        struct list_head *head = &(info->v2p_entry_lists);
 849        struct v2p_entry *entry;
 850
 851        list_for_each_entry(entry, head, l)
 852                if ((entry->v.chn == v->chn) &&
 853                    (entry->v.tgt == v->tgt) &&
 854                    (entry->v.lun == v->lun))
 855                        return entry;
 856
 857        return NULL;
 858}
 859
 860/*
 861  Add a new translation entry
 862*/
 863static int scsiback_add_translation_entry(struct vscsibk_info *info,
 864                                          char *phy, struct ids_tuple *v)
 865{
 866        int err = 0;
 867        struct v2p_entry *new;
 868        unsigned long flags;
 869        char *lunp;
 870        unsigned long long unpacked_lun;
 871        struct se_lun *se_lun;
 872        struct scsiback_tpg *tpg_entry, *tpg = NULL;
 873        char *error = "doesn't exist";
 874
 875        lunp = strrchr(phy, ':');
 876        if (!lunp) {
 877                pr_err("illegal format of physical device %s\n", phy);
 878                return -EINVAL;
 879        }
 880        *lunp = 0;
 881        lunp++;
 882        err = kstrtoull(lunp, 10, &unpacked_lun);
 883        if (err < 0) {
 884                pr_err("lun number not valid: %s\n", lunp);
 885                return err;
 886        }
 887
 888        mutex_lock(&scsiback_mutex);
 889        list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
 890                if (!strcmp(phy, tpg_entry->tport->tport_name) ||
 891                    !strcmp(phy, tpg_entry->param_alias)) {
 892                        mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
 893                        hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
 894                                if (se_lun->unpacked_lun == unpacked_lun) {
 895                                        if (!tpg_entry->tpg_nexus)
 896                                                error = "nexus undefined";
 897                                        else
 898                                                tpg = tpg_entry;
 899                                        break;
 900                                }
 901                        }
 902                        mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
 903                        break;
 904                }
 905        }
 906        if (tpg) {
 907                mutex_lock(&tpg->tv_tpg_mutex);
 908                tpg->tv_tpg_fe_count++;
 909                mutex_unlock(&tpg->tv_tpg_mutex);
 910        }
 911        mutex_unlock(&scsiback_mutex);
 912
 913        if (!tpg) {
 914                pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
 915                return -ENODEV;
 916        }
 917
 918        new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
 919        if (new == NULL) {
 920                err = -ENOMEM;
 921                goto out_free;
 922        }
 923
 924        spin_lock_irqsave(&info->v2p_lock, flags);
 925
 926        /* Check double assignment to identical virtual ID */
 927        if (scsiback_chk_translation_entry(info, v)) {
 928                pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 929                err = -EEXIST;
 930                goto out;
 931        }
 932
 933        /* Create a new translation entry and add to the list */
 934        kref_init(&new->kref);
 935        new->v = *v;
 936        new->tpg = tpg;
 937        new->lun = unpacked_lun;
 938        list_add_tail(&new->l, &info->v2p_entry_lists);
 939
 940out:
 941        spin_unlock_irqrestore(&info->v2p_lock, flags);
 942
 943out_free:
 944        if (err) {
 945                mutex_lock(&tpg->tv_tpg_mutex);
 946                tpg->tv_tpg_fe_count--;
 947                mutex_unlock(&tpg->tv_tpg_mutex);
 948                kfree(new);
 949        }
 950
 951        return err;
 952}
 953
 954static void __scsiback_del_translation_entry(struct v2p_entry *entry)
 955{
 956        list_del(&entry->l);
 957        kref_put(&entry->kref, scsiback_free_translation_entry);
 958}
 959
 960/*
 961  Delete the translation entry specified
 962*/
 963static int scsiback_del_translation_entry(struct vscsibk_info *info,
 964                                          struct ids_tuple *v)
 965{
 966        struct v2p_entry *entry;
 967        unsigned long flags;
 968        int ret = 0;
 969
 970        spin_lock_irqsave(&info->v2p_lock, flags);
 971        /* Find out the translation entry specified */
 972        entry = scsiback_chk_translation_entry(info, v);
 973        if (entry)
 974                __scsiback_del_translation_entry(entry);
 975        else
 976                ret = -ENOENT;
 977
 978        spin_unlock_irqrestore(&info->v2p_lock, flags);
 979        return ret;
 980}
 981
 982static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
 983                                char *phy, struct ids_tuple *vir, int try)
 984{
 985        struct v2p_entry *entry;
 986        unsigned long flags;
 987        int err;
 988
 989        if (try) {
 990                spin_lock_irqsave(&info->v2p_lock, flags);
 991                entry = scsiback_chk_translation_entry(info, vir);
 992                spin_unlock_irqrestore(&info->v2p_lock, flags);
 993                if (entry)
 994                        return;
 995        }
 996        if (!scsiback_add_translation_entry(info, phy, vir)) {
 997                if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
 998                                  "%d", XenbusStateInitialised)) {
 999                        pr_err("xenbus_printf error %s\n", state);
1000                        scsiback_del_translation_entry(info, vir);
1001                }
1002        } else if (!try) {
1003                err = xenbus_printf(XBT_NIL, info->dev->nodename, state,
1004                              "%d", XenbusStateClosed);
1005                if (err)
1006                        xenbus_dev_error(info->dev, err,
1007                                "%s: writing %s", __func__, state);
1008        }
1009}
1010
1011static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1012                                struct ids_tuple *vir)
1013{
1014        if (!scsiback_del_translation_entry(info, vir)) {
1015                if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1016                                  "%d", XenbusStateClosed))
1017                        pr_err("xenbus_printf error %s\n", state);
1018        }
1019}
1020
1021#define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1022#define VSCSIBACK_OP_UPDATEDEV_STATE    2
1023
1024static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1025                                     char *ent)
1026{
1027        int err;
1028        struct ids_tuple vir;
1029        char *val;
1030        int device_state;
1031        char phy[VSCSI_NAMELEN];
1032        char str[64];
1033        char state[64];
1034        struct xenbus_device *dev = info->dev;
1035
1036        /* read status */
1037        snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1038        err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1039        if (XENBUS_EXIST_ERR(err))
1040                return;
1041
1042        /* physical SCSI device */
1043        snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1044        val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1045        if (IS_ERR(val)) {
1046                err = xenbus_printf(XBT_NIL, dev->nodename, state,
1047                              "%d", XenbusStateClosed);
1048                if (err)
1049                        xenbus_dev_error(info->dev, err,
1050                                "%s: writing %s", __func__, state);
1051                return;
1052        }
1053        strlcpy(phy, val, VSCSI_NAMELEN);
1054        kfree(val);
1055
1056        /* virtual SCSI device */
1057        snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1058        err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1059                           &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1060        if (XENBUS_EXIST_ERR(err)) {
1061                err = xenbus_printf(XBT_NIL, dev->nodename, state,
1062                              "%d", XenbusStateClosed);
1063                if (err)
1064                        xenbus_dev_error(info->dev, err,
1065                                "%s: writing %s", __func__, state);
1066                return;
1067        }
1068
1069        switch (op) {
1070        case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1071                switch (device_state) {
1072                case XenbusStateInitialising:
1073                        scsiback_do_add_lun(info, state, phy, &vir, 0);
1074                        break;
1075                case XenbusStateConnected:
1076                        scsiback_do_add_lun(info, state, phy, &vir, 1);
1077                        break;
1078                case XenbusStateClosing:
1079                        scsiback_do_del_lun(info, state, &vir);
1080                        break;
1081                default:
1082                        break;
1083                }
1084                break;
1085
1086        case VSCSIBACK_OP_UPDATEDEV_STATE:
1087                if (device_state == XenbusStateInitialised) {
1088                        /* modify vscsi-devs/dev-x/state */
1089                        if (xenbus_printf(XBT_NIL, dev->nodename, state,
1090                                          "%d", XenbusStateConnected)) {
1091                                pr_err("xenbus_printf error %s\n", str);
1092                                scsiback_del_translation_entry(info, &vir);
1093                                xenbus_printf(XBT_NIL, dev->nodename, state,
1094                                              "%d", XenbusStateClosed);
1095                        }
1096                }
1097                break;
1098        /* When it is necessary, processing is added here. */
1099        default:
1100                break;
1101        }
1102}
1103
1104static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1105{
1106        int i;
1107        char **dir;
1108        unsigned int ndir = 0;
1109
1110        dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1111                               &ndir);
1112        if (IS_ERR(dir))
1113                return;
1114
1115        for (i = 0; i < ndir; i++)
1116                scsiback_do_1lun_hotplug(info, op, dir[i]);
1117
1118        kfree(dir);
1119}
1120
1121static void scsiback_frontend_changed(struct xenbus_device *dev,
1122                                        enum xenbus_state frontend_state)
1123{
1124        struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1125
1126        switch (frontend_state) {
1127        case XenbusStateInitialising:
1128                break;
1129
1130        case XenbusStateInitialised:
1131                if (scsiback_map(info))
1132                        break;
1133
1134                scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1135                xenbus_switch_state(dev, XenbusStateConnected);
1136                break;
1137
1138        case XenbusStateConnected:
1139                scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1140
1141                if (dev->state == XenbusStateConnected)
1142                        break;
1143
1144                xenbus_switch_state(dev, XenbusStateConnected);
1145                break;
1146
1147        case XenbusStateClosing:
1148                if (info->irq)
1149                        scsiback_disconnect(info);
1150
1151                xenbus_switch_state(dev, XenbusStateClosing);
1152                break;
1153
1154        case XenbusStateClosed:
1155                xenbus_switch_state(dev, XenbusStateClosed);
1156                if (xenbus_dev_is_online(dev))
1157                        break;
1158                fallthrough;    /* if not online */
1159        case XenbusStateUnknown:
1160                device_unregister(&dev->dev);
1161                break;
1162
1163        case XenbusStateReconfiguring:
1164                scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1165                xenbus_switch_state(dev, XenbusStateReconfigured);
1166
1167                break;
1168
1169        default:
1170                xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1171                                        frontend_state);
1172                break;
1173        }
1174}
1175
1176/*
1177  Release the translation entry specfied
1178*/
1179static void scsiback_release_translation_entry(struct vscsibk_info *info)
1180{
1181        struct v2p_entry *entry, *tmp;
1182        struct list_head *head = &(info->v2p_entry_lists);
1183        unsigned long flags;
1184
1185        spin_lock_irqsave(&info->v2p_lock, flags);
1186
1187        list_for_each_entry_safe(entry, tmp, head, l)
1188                __scsiback_del_translation_entry(entry);
1189
1190        spin_unlock_irqrestore(&info->v2p_lock, flags);
1191}
1192
1193static int scsiback_remove(struct xenbus_device *dev)
1194{
1195        struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1196
1197        if (info->irq)
1198                scsiback_disconnect(info);
1199
1200        scsiback_release_translation_entry(info);
1201
1202        gnttab_page_cache_shrink(&info->free_pages, 0);
1203
1204        dev_set_drvdata(&dev->dev, NULL);
1205
1206        return 0;
1207}
1208
1209static int scsiback_probe(struct xenbus_device *dev,
1210                           const struct xenbus_device_id *id)
1211{
1212        int err;
1213
1214        struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1215                                            GFP_KERNEL);
1216
1217        pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1218
1219        if (!info) {
1220                xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1221                return -ENOMEM;
1222        }
1223        info->dev = dev;
1224        dev_set_drvdata(&dev->dev, info);
1225
1226        info->domid = dev->otherend_id;
1227        spin_lock_init(&info->ring_lock);
1228        atomic_set(&info->nr_unreplied_reqs, 0);
1229        init_waitqueue_head(&info->waiting_to_free);
1230        info->dev = dev;
1231        info->irq = 0;
1232        INIT_LIST_HEAD(&info->v2p_entry_lists);
1233        spin_lock_init(&info->v2p_lock);
1234        gnttab_page_cache_init(&info->free_pages);
1235
1236        err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1237                            SG_ALL);
1238        if (err)
1239                xenbus_dev_error(dev, err, "writing feature-sg-grant");
1240
1241        err = xenbus_switch_state(dev, XenbusStateInitWait);
1242        if (err)
1243                goto fail;
1244
1245        return 0;
1246
1247fail:
1248        pr_warn("%s failed\n", __func__);
1249        scsiback_remove(dev);
1250
1251        return err;
1252}
1253
1254static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1255{
1256        switch (tport->tport_proto_id) {
1257        case SCSI_PROTOCOL_SAS:
1258                return "SAS";
1259        case SCSI_PROTOCOL_FCP:
1260                return "FCP";
1261        case SCSI_PROTOCOL_ISCSI:
1262                return "iSCSI";
1263        default:
1264                break;
1265        }
1266
1267        return "Unknown";
1268}
1269
1270static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1271{
1272        struct scsiback_tpg *tpg = container_of(se_tpg,
1273                                struct scsiback_tpg, se_tpg);
1274        struct scsiback_tport *tport = tpg->tport;
1275
1276        return &tport->tport_name[0];
1277}
1278
1279static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1280{
1281        struct scsiback_tpg *tpg = container_of(se_tpg,
1282                                struct scsiback_tpg, se_tpg);
1283        return tpg->tport_tpgt;
1284}
1285
1286static struct se_wwn *
1287scsiback_make_tport(struct target_fabric_configfs *tf,
1288                     struct config_group *group,
1289                     const char *name)
1290{
1291        struct scsiback_tport *tport;
1292        char *ptr;
1293        u64 wwpn = 0;
1294        int off = 0;
1295
1296        tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1297        if (!tport)
1298                return ERR_PTR(-ENOMEM);
1299
1300        tport->tport_wwpn = wwpn;
1301        /*
1302         * Determine the emulated Protocol Identifier and Target Port Name
1303         * based on the incoming configfs directory name.
1304         */
1305        ptr = strstr(name, "naa.");
1306        if (ptr) {
1307                tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1308                goto check_len;
1309        }
1310        ptr = strstr(name, "fc.");
1311        if (ptr) {
1312                tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1313                off = 3; /* Skip over "fc." */
1314                goto check_len;
1315        }
1316        ptr = strstr(name, "iqn.");
1317        if (ptr) {
1318                tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1319                goto check_len;
1320        }
1321
1322        pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1323        kfree(tport);
1324        return ERR_PTR(-EINVAL);
1325
1326check_len:
1327        if (strlen(name) >= VSCSI_NAMELEN) {
1328                pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1329                        scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1330                kfree(tport);
1331                return ERR_PTR(-EINVAL);
1332        }
1333        snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1334
1335        pr_debug("Allocated emulated Target %s Address: %s\n",
1336                 scsiback_dump_proto_id(tport), name);
1337
1338        return &tport->tport_wwn;
1339}
1340
1341static void scsiback_drop_tport(struct se_wwn *wwn)
1342{
1343        struct scsiback_tport *tport = container_of(wwn,
1344                                struct scsiback_tport, tport_wwn);
1345
1346        pr_debug("Deallocating emulated Target %s Address: %s\n",
1347                 scsiback_dump_proto_id(tport), tport->tport_name);
1348
1349        kfree(tport);
1350}
1351
1352static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1353{
1354        return 1;
1355}
1356
1357static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1358{
1359        return transport_generic_free_cmd(se_cmd, 0);
1360}
1361
1362static void scsiback_release_cmd(struct se_cmd *se_cmd)
1363{
1364        target_free_tag(se_cmd->se_sess, se_cmd);
1365}
1366
1367static u32 scsiback_sess_get_index(struct se_session *se_sess)
1368{
1369        return 0;
1370}
1371
1372static int scsiback_write_pending(struct se_cmd *se_cmd)
1373{
1374        /* Go ahead and process the write immediately */
1375        target_execute_cmd(se_cmd);
1376
1377        return 0;
1378}
1379
1380static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1381{
1382}
1383
1384static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1385{
1386        return 0;
1387}
1388
1389static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1390{
1391        struct vscsibk_pend *pending_req = container_of(se_cmd,
1392                                struct vscsibk_pend, se_cmd);
1393
1394        pending_req->result = SAM_STAT_GOOD;
1395        scsiback_cmd_done(pending_req);
1396        return 0;
1397}
1398
1399static int scsiback_queue_status(struct se_cmd *se_cmd)
1400{
1401        struct vscsibk_pend *pending_req = container_of(se_cmd,
1402                                struct vscsibk_pend, se_cmd);
1403
1404        if (se_cmd->sense_buffer &&
1405            ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1406             (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1407                pending_req->result = (DRIVER_SENSE << 24) |
1408                                      SAM_STAT_CHECK_CONDITION;
1409        else
1410                pending_req->result = se_cmd->scsi_status;
1411
1412        scsiback_cmd_done(pending_req);
1413        return 0;
1414}
1415
1416static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1417{
1418        struct vscsibk_pend *pending_req = container_of(se_cmd,
1419                                struct vscsibk_pend, se_cmd);
1420
1421        complete(&pending_req->tmr_done);
1422}
1423
1424static void scsiback_aborted_task(struct se_cmd *se_cmd)
1425{
1426}
1427
1428static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1429                                             char *page)
1430{
1431        struct se_portal_group *se_tpg = param_to_tpg(item);
1432        struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1433                                                se_tpg);
1434        ssize_t rb;
1435
1436        mutex_lock(&tpg->tv_tpg_mutex);
1437        rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1438        mutex_unlock(&tpg->tv_tpg_mutex);
1439
1440        return rb;
1441}
1442
1443static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1444                                              const char *page, size_t count)
1445{
1446        struct se_portal_group *se_tpg = param_to_tpg(item);
1447        struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1448                                                se_tpg);
1449        int len;
1450
1451        if (strlen(page) >= VSCSI_NAMELEN) {
1452                pr_err("param alias: %s, exceeds max: %d\n", page,
1453                        VSCSI_NAMELEN);
1454                return -EINVAL;
1455        }
1456
1457        mutex_lock(&tpg->tv_tpg_mutex);
1458        len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1459        if (tpg->param_alias[len - 1] == '\n')
1460                tpg->param_alias[len - 1] = '\0';
1461        mutex_unlock(&tpg->tv_tpg_mutex);
1462
1463        return count;
1464}
1465
1466CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1467
1468static struct configfs_attribute *scsiback_param_attrs[] = {
1469        &scsiback_tpg_param_attr_alias,
1470        NULL,
1471};
1472
1473static int scsiback_alloc_sess_cb(struct se_portal_group *se_tpg,
1474                                  struct se_session *se_sess, void *p)
1475{
1476        struct scsiback_tpg *tpg = container_of(se_tpg,
1477                                struct scsiback_tpg, se_tpg);
1478
1479        tpg->tpg_nexus = p;
1480        return 0;
1481}
1482
1483static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1484                                const char *name)
1485{
1486        struct scsiback_nexus *tv_nexus;
1487        int ret = 0;
1488
1489        mutex_lock(&tpg->tv_tpg_mutex);
1490        if (tpg->tpg_nexus) {
1491                pr_debug("tpg->tpg_nexus already exists\n");
1492                ret = -EEXIST;
1493                goto out_unlock;
1494        }
1495
1496        tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1497        if (!tv_nexus) {
1498                ret = -ENOMEM;
1499                goto out_unlock;
1500        }
1501
1502        tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg,
1503                                                     VSCSI_DEFAULT_SESSION_TAGS,
1504                                                     sizeof(struct vscsibk_pend),
1505                                                     TARGET_PROT_NORMAL, name,
1506                                                     tv_nexus, scsiback_alloc_sess_cb);
1507        if (IS_ERR(tv_nexus->tvn_se_sess)) {
1508                kfree(tv_nexus);
1509                ret = -ENOMEM;
1510                goto out_unlock;
1511        }
1512
1513out_unlock:
1514        mutex_unlock(&tpg->tv_tpg_mutex);
1515        return ret;
1516}
1517
1518static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1519{
1520        struct se_session *se_sess;
1521        struct scsiback_nexus *tv_nexus;
1522
1523        mutex_lock(&tpg->tv_tpg_mutex);
1524        tv_nexus = tpg->tpg_nexus;
1525        if (!tv_nexus) {
1526                mutex_unlock(&tpg->tv_tpg_mutex);
1527                return -ENODEV;
1528        }
1529
1530        se_sess = tv_nexus->tvn_se_sess;
1531        if (!se_sess) {
1532                mutex_unlock(&tpg->tv_tpg_mutex);
1533                return -ENODEV;
1534        }
1535
1536        if (tpg->tv_tpg_port_count != 0) {
1537                mutex_unlock(&tpg->tv_tpg_mutex);
1538                pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1539                        tpg->tv_tpg_port_count);
1540                return -EBUSY;
1541        }
1542
1543        if (tpg->tv_tpg_fe_count != 0) {
1544                mutex_unlock(&tpg->tv_tpg_mutex);
1545                pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1546                        tpg->tv_tpg_fe_count);
1547                return -EBUSY;
1548        }
1549
1550        pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1551                scsiback_dump_proto_id(tpg->tport),
1552                tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1553
1554        /*
1555         * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1556         */
1557        target_remove_session(se_sess);
1558        tpg->tpg_nexus = NULL;
1559        mutex_unlock(&tpg->tv_tpg_mutex);
1560
1561        kfree(tv_nexus);
1562        return 0;
1563}
1564
1565static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1566{
1567        struct se_portal_group *se_tpg = to_tpg(item);
1568        struct scsiback_tpg *tpg = container_of(se_tpg,
1569                                struct scsiback_tpg, se_tpg);
1570        struct scsiback_nexus *tv_nexus;
1571        ssize_t ret;
1572
1573        mutex_lock(&tpg->tv_tpg_mutex);
1574        tv_nexus = tpg->tpg_nexus;
1575        if (!tv_nexus) {
1576                mutex_unlock(&tpg->tv_tpg_mutex);
1577                return -ENODEV;
1578        }
1579        ret = snprintf(page, PAGE_SIZE, "%s\n",
1580                        tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1581        mutex_unlock(&tpg->tv_tpg_mutex);
1582
1583        return ret;
1584}
1585
1586static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
1587                const char *page, size_t count)
1588{
1589        struct se_portal_group *se_tpg = to_tpg(item);
1590        struct scsiback_tpg *tpg = container_of(se_tpg,
1591                                struct scsiback_tpg, se_tpg);
1592        struct scsiback_tport *tport_wwn = tpg->tport;
1593        unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1594        int ret;
1595        /*
1596         * Shutdown the active I_T nexus if 'NULL' is passed.
1597         */
1598        if (!strncmp(page, "NULL", 4)) {
1599                ret = scsiback_drop_nexus(tpg);
1600                return (!ret) ? count : ret;
1601        }
1602        /*
1603         * Otherwise make sure the passed virtual Initiator port WWN matches
1604         * the fabric protocol_id set in scsiback_make_tport(), and call
1605         * scsiback_make_nexus().
1606         */
1607        if (strlen(page) >= VSCSI_NAMELEN) {
1608                pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1609                        page, VSCSI_NAMELEN);
1610                return -EINVAL;
1611        }
1612        snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1613
1614        ptr = strstr(i_port, "naa.");
1615        if (ptr) {
1616                if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1617                        pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1618                                i_port, scsiback_dump_proto_id(tport_wwn));
1619                        return -EINVAL;
1620                }
1621                port_ptr = &i_port[0];
1622                goto check_newline;
1623        }
1624        ptr = strstr(i_port, "fc.");
1625        if (ptr) {
1626                if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1627                        pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1628                                i_port, scsiback_dump_proto_id(tport_wwn));
1629                        return -EINVAL;
1630                }
1631                port_ptr = &i_port[3]; /* Skip over "fc." */
1632                goto check_newline;
1633        }
1634        ptr = strstr(i_port, "iqn.");
1635        if (ptr) {
1636                if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1637                        pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1638                                i_port, scsiback_dump_proto_id(tport_wwn));
1639                        return -EINVAL;
1640                }
1641                port_ptr = &i_port[0];
1642                goto check_newline;
1643        }
1644        pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1645                i_port);
1646        return -EINVAL;
1647        /*
1648         * Clear any trailing newline for the NAA WWN
1649         */
1650check_newline:
1651        if (i_port[strlen(i_port) - 1] == '\n')
1652                i_port[strlen(i_port) - 1] = '\0';
1653
1654        ret = scsiback_make_nexus(tpg, port_ptr);
1655        if (ret < 0)
1656                return ret;
1657
1658        return count;
1659}
1660
1661CONFIGFS_ATTR(scsiback_tpg_, nexus);
1662
1663static struct configfs_attribute *scsiback_tpg_attrs[] = {
1664        &scsiback_tpg_attr_nexus,
1665        NULL,
1666};
1667
1668static ssize_t
1669scsiback_wwn_version_show(struct config_item *item, char *page)
1670{
1671        return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1672                UTS_RELEASE"\n",
1673                VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1674}
1675
1676CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1677
1678static struct configfs_attribute *scsiback_wwn_attrs[] = {
1679        &scsiback_wwn_attr_version,
1680        NULL,
1681};
1682
1683static int scsiback_port_link(struct se_portal_group *se_tpg,
1684                               struct se_lun *lun)
1685{
1686        struct scsiback_tpg *tpg = container_of(se_tpg,
1687                                struct scsiback_tpg, se_tpg);
1688
1689        mutex_lock(&tpg->tv_tpg_mutex);
1690        tpg->tv_tpg_port_count++;
1691        mutex_unlock(&tpg->tv_tpg_mutex);
1692
1693        return 0;
1694}
1695
1696static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1697                                  struct se_lun *lun)
1698{
1699        struct scsiback_tpg *tpg = container_of(se_tpg,
1700                                struct scsiback_tpg, se_tpg);
1701
1702        mutex_lock(&tpg->tv_tpg_mutex);
1703        tpg->tv_tpg_port_count--;
1704        mutex_unlock(&tpg->tv_tpg_mutex);
1705}
1706
1707static struct se_portal_group *
1708scsiback_make_tpg(struct se_wwn *wwn, const char *name)
1709{
1710        struct scsiback_tport *tport = container_of(wwn,
1711                        struct scsiback_tport, tport_wwn);
1712
1713        struct scsiback_tpg *tpg;
1714        u16 tpgt;
1715        int ret;
1716
1717        if (strstr(name, "tpgt_") != name)
1718                return ERR_PTR(-EINVAL);
1719        ret = kstrtou16(name + 5, 10, &tpgt);
1720        if (ret)
1721                return ERR_PTR(ret);
1722
1723        tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1724        if (!tpg)
1725                return ERR_PTR(-ENOMEM);
1726
1727        mutex_init(&tpg->tv_tpg_mutex);
1728        INIT_LIST_HEAD(&tpg->tv_tpg_list);
1729        INIT_LIST_HEAD(&tpg->info_list);
1730        tpg->tport = tport;
1731        tpg->tport_tpgt = tpgt;
1732
1733        ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1734        if (ret < 0) {
1735                kfree(tpg);
1736                return NULL;
1737        }
1738        mutex_lock(&scsiback_mutex);
1739        list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1740        mutex_unlock(&scsiback_mutex);
1741
1742        return &tpg->se_tpg;
1743}
1744
1745static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1746{
1747        struct scsiback_tpg *tpg = container_of(se_tpg,
1748                                struct scsiback_tpg, se_tpg);
1749
1750        mutex_lock(&scsiback_mutex);
1751        list_del(&tpg->tv_tpg_list);
1752        mutex_unlock(&scsiback_mutex);
1753        /*
1754         * Release the virtual I_T Nexus for this xen-pvscsi TPG
1755         */
1756        scsiback_drop_nexus(tpg);
1757        /*
1758         * Deregister the se_tpg from TCM.
1759         */
1760        core_tpg_deregister(se_tpg);
1761        kfree(tpg);
1762}
1763
1764static int scsiback_check_true(struct se_portal_group *se_tpg)
1765{
1766        return 1;
1767}
1768
1769static int scsiback_check_false(struct se_portal_group *se_tpg)
1770{
1771        return 0;
1772}
1773
1774static const struct target_core_fabric_ops scsiback_ops = {
1775        .module                         = THIS_MODULE,
1776        .fabric_name                    = "xen-pvscsi",
1777        .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1778        .tpg_get_tag                    = scsiback_get_tag,
1779        .tpg_check_demo_mode            = scsiback_check_true,
1780        .tpg_check_demo_mode_cache      = scsiback_check_true,
1781        .tpg_check_demo_mode_write_protect = scsiback_check_false,
1782        .tpg_check_prod_mode_write_protect = scsiback_check_false,
1783        .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1784        .check_stop_free                = scsiback_check_stop_free,
1785        .release_cmd                    = scsiback_release_cmd,
1786        .sess_get_index                 = scsiback_sess_get_index,
1787        .sess_get_initiator_sid         = NULL,
1788        .write_pending                  = scsiback_write_pending,
1789        .set_default_node_attributes    = scsiback_set_default_node_attrs,
1790        .get_cmd_state                  = scsiback_get_cmd_state,
1791        .queue_data_in                  = scsiback_queue_data_in,
1792        .queue_status                   = scsiback_queue_status,
1793        .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1794        .aborted_task                   = scsiback_aborted_task,
1795        /*
1796         * Setup callers for generic logic in target_core_fabric_configfs.c
1797         */
1798        .fabric_make_wwn                = scsiback_make_tport,
1799        .fabric_drop_wwn                = scsiback_drop_tport,
1800        .fabric_make_tpg                = scsiback_make_tpg,
1801        .fabric_drop_tpg                = scsiback_drop_tpg,
1802        .fabric_post_link               = scsiback_port_link,
1803        .fabric_pre_unlink              = scsiback_port_unlink,
1804
1805        .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1806        .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1807        .tfc_tpg_param_attrs            = scsiback_param_attrs,
1808};
1809
1810static const struct xenbus_device_id scsiback_ids[] = {
1811        { "vscsi" },
1812        { "" }
1813};
1814
1815static struct xenbus_driver scsiback_driver = {
1816        .ids                    = scsiback_ids,
1817        .probe                  = scsiback_probe,
1818        .remove                 = scsiback_remove,
1819        .otherend_changed       = scsiback_frontend_changed
1820};
1821
1822static int __init scsiback_init(void)
1823{
1824        int ret;
1825
1826        if (!xen_domain())
1827                return -ENODEV;
1828
1829        pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1830                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1831
1832        ret = xenbus_register_backend(&scsiback_driver);
1833        if (ret)
1834                goto out;
1835
1836        ret = target_register_template(&scsiback_ops);
1837        if (ret)
1838                goto out_unregister_xenbus;
1839
1840        return 0;
1841
1842out_unregister_xenbus:
1843        xenbus_unregister_driver(&scsiback_driver);
1844out:
1845        pr_err("%s: error %d\n", __func__, ret);
1846        return ret;
1847}
1848
1849static void __exit scsiback_exit(void)
1850{
1851        target_unregister_template(&scsiback_ops);
1852        xenbus_unregister_driver(&scsiback_driver);
1853}
1854
1855module_init(scsiback_init);
1856module_exit(scsiback_exit);
1857
1858MODULE_DESCRIPTION("Xen SCSI backend driver");
1859MODULE_LICENSE("Dual BSD/GPL");
1860MODULE_ALIAS("xen-backend:vscsi");
1861MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");
1862