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