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        int ring_error;
  95
  96        spinlock_t ring_lock;
  97        atomic_t nr_unreplied_reqs;
  98
  99        spinlock_t v2p_lock;
 100        struct list_head v2p_entry_lists;
 101
 102        wait_queue_head_t waiting_to_free;
 103};
 104
 105/* theoretical maximum of grants for one request */
 106#define VSCSI_MAX_GRANTS        (SG_ALL + VSCSIIF_SG_TABLESIZE)
 107
 108/*
 109 * VSCSI_GRANT_BATCH is the maximum number of grants to be processed in one
 110 * call to map/unmap grants. Don't choose it too large, as there are arrays
 111 * with VSCSI_GRANT_BATCH elements allocated on the stack.
 112 */
 113#define VSCSI_GRANT_BATCH       16
 114
 115struct vscsibk_pend {
 116        uint16_t rqid;
 117
 118        uint8_t cmnd[VSCSIIF_MAX_COMMAND_SIZE];
 119        uint8_t cmd_len;
 120
 121        uint8_t sc_data_direction;
 122        uint16_t n_sg;          /* real length of SG list */
 123        uint16_t n_grants;      /* SG pages and potentially SG list */
 124        uint32_t data_len;
 125        uint32_t result;
 126
 127        struct vscsibk_info *info;
 128        struct v2p_entry *v2p;
 129        struct scatterlist *sgl;
 130
 131        uint8_t sense_buffer[VSCSIIF_SENSE_BUFFERSIZE];
 132
 133        grant_handle_t grant_handles[VSCSI_MAX_GRANTS];
 134        struct page *pages[VSCSI_MAX_GRANTS];
 135
 136        struct se_cmd se_cmd;
 137};
 138
 139struct scsiback_tmr {
 140        atomic_t tmr_complete;
 141        wait_queue_head_t tmr_wait;
 142};
 143
 144#define VSCSI_DEFAULT_SESSION_TAGS      128
 145
 146struct scsiback_nexus {
 147        /* Pointer to TCM session for I_T Nexus */
 148        struct se_session *tvn_se_sess;
 149};
 150
 151struct scsiback_tport {
 152        /* SCSI protocol the tport is providing */
 153        u8 tport_proto_id;
 154        /* Binary World Wide unique Port Name for pvscsi Target port */
 155        u64 tport_wwpn;
 156        /* ASCII formatted WWPN for pvscsi Target port */
 157        char tport_name[VSCSI_NAMELEN];
 158        /* Returned by scsiback_make_tport() */
 159        struct se_wwn tport_wwn;
 160};
 161
 162struct scsiback_tpg {
 163        /* scsiback port target portal group tag for TCM */
 164        u16 tport_tpgt;
 165        /* track number of TPG Port/Lun Links wrt explicit I_T Nexus shutdown */
 166        int tv_tpg_port_count;
 167        /* xen-pvscsi references to tpg_nexus, protected by tv_tpg_mutex */
 168        int tv_tpg_fe_count;
 169        /* list for scsiback_list */
 170        struct list_head tv_tpg_list;
 171        /* Used to protect access for tpg_nexus */
 172        struct mutex tv_tpg_mutex;
 173        /* Pointer to the TCM pvscsi I_T Nexus for this TPG endpoint */
 174        struct scsiback_nexus *tpg_nexus;
 175        /* Pointer back to scsiback_tport */
 176        struct scsiback_tport *tport;
 177        /* Returned by scsiback_make_tpg() */
 178        struct se_portal_group se_tpg;
 179        /* alias used in xenstore */
 180        char param_alias[VSCSI_NAMELEN];
 181        /* list of info structures related to this target portal group */
 182        struct list_head info_list;
 183};
 184
 185#define SCSIBACK_INVALID_HANDLE (~0)
 186
 187static bool log_print_stat;
 188module_param(log_print_stat, bool, 0644);
 189
 190static int scsiback_max_buffer_pages = 1024;
 191module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644);
 192MODULE_PARM_DESC(max_buffer_pages,
 193"Maximum number of free pages to keep in backend buffer");
 194
 195static DEFINE_SPINLOCK(free_pages_lock);
 196static int free_pages_num;
 197static LIST_HEAD(scsiback_free_pages);
 198
 199/* Global spinlock to protect scsiback TPG list */
 200static DEFINE_MUTEX(scsiback_mutex);
 201static LIST_HEAD(scsiback_list);
 202
 203static void scsiback_get(struct vscsibk_info *info)
 204{
 205        atomic_inc(&info->nr_unreplied_reqs);
 206}
 207
 208static void scsiback_put(struct vscsibk_info *info)
 209{
 210        if (atomic_dec_and_test(&info->nr_unreplied_reqs))
 211                wake_up(&info->waiting_to_free);
 212}
 213
 214static void put_free_pages(struct page **page, int num)
 215{
 216        unsigned long flags;
 217        int i = free_pages_num + num, n = num;
 218
 219        if (num == 0)
 220                return;
 221        if (i > scsiback_max_buffer_pages) {
 222                n = min(num, i - scsiback_max_buffer_pages);
 223                gnttab_free_pages(n, page + num - n);
 224                n = num - n;
 225        }
 226        spin_lock_irqsave(&free_pages_lock, flags);
 227        for (i = 0; i < n; i++)
 228                list_add(&page[i]->lru, &scsiback_free_pages);
 229        free_pages_num += n;
 230        spin_unlock_irqrestore(&free_pages_lock, flags);
 231}
 232
 233static int get_free_page(struct page **page)
 234{
 235        unsigned long flags;
 236
 237        spin_lock_irqsave(&free_pages_lock, flags);
 238        if (list_empty(&scsiback_free_pages)) {
 239                spin_unlock_irqrestore(&free_pages_lock, flags);
 240                return gnttab_alloc_pages(1, page);
 241        }
 242        page[0] = list_first_entry(&scsiback_free_pages, struct page, lru);
 243        list_del(&page[0]->lru);
 244        free_pages_num--;
 245        spin_unlock_irqrestore(&free_pages_lock, flags);
 246        return 0;
 247}
 248
 249static unsigned long vaddr_page(struct page *page)
 250{
 251        unsigned long pfn = page_to_pfn(page);
 252
 253        return (unsigned long)pfn_to_kaddr(pfn);
 254}
 255
 256static unsigned long vaddr(struct vscsibk_pend *req, int seg)
 257{
 258        return vaddr_page(req->pages[seg]);
 259}
 260
 261static void scsiback_print_status(char *sense_buffer, int errors,
 262                                        struct vscsibk_pend *pending_req)
 263{
 264        struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 265
 266        pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
 267               tpg->tport->tport_name, pending_req->v2p->lun,
 268               pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
 269               host_byte(errors), driver_byte(errors));
 270}
 271
 272static void scsiback_fast_flush_area(struct vscsibk_pend *req)
 273{
 274        struct gnttab_unmap_grant_ref unmap[VSCSI_GRANT_BATCH];
 275        struct page *pages[VSCSI_GRANT_BATCH];
 276        unsigned int i, invcount = 0;
 277        grant_handle_t handle;
 278        int err;
 279
 280        kfree(req->sgl);
 281        req->sgl = NULL;
 282        req->n_sg = 0;
 283
 284        if (!req->n_grants)
 285                return;
 286
 287        for (i = 0; i < req->n_grants; i++) {
 288                handle = req->grant_handles[i];
 289                if (handle == SCSIBACK_INVALID_HANDLE)
 290                        continue;
 291                gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
 292                                    GNTMAP_host_map, handle);
 293                req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 294                pages[invcount] = req->pages[i];
 295                put_page(pages[invcount]);
 296                invcount++;
 297                if (invcount < VSCSI_GRANT_BATCH)
 298                        continue;
 299                err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 300                BUG_ON(err);
 301                invcount = 0;
 302        }
 303
 304        if (invcount) {
 305                err = gnttab_unmap_refs(unmap, NULL, pages, invcount);
 306                BUG_ON(err);
 307        }
 308
 309        put_free_pages(req->pages, req->n_grants);
 310        req->n_grants = 0;
 311}
 312
 313static void scsiback_free_translation_entry(struct kref *kref)
 314{
 315        struct v2p_entry *entry = container_of(kref, struct v2p_entry, kref);
 316        struct scsiback_tpg *tpg = entry->tpg;
 317
 318        mutex_lock(&tpg->tv_tpg_mutex);
 319        tpg->tv_tpg_fe_count--;
 320        mutex_unlock(&tpg->tv_tpg_mutex);
 321
 322        kfree(entry);
 323}
 324
 325static void scsiback_send_response(struct vscsibk_info *info,
 326                        char *sense_buffer, int32_t result, uint32_t resid,
 327                        uint16_t rqid)
 328{
 329        struct vscsiif_response *ring_res;
 330        int notify;
 331        struct scsi_sense_hdr sshdr;
 332        unsigned long flags;
 333        unsigned len;
 334
 335        spin_lock_irqsave(&info->ring_lock, flags);
 336
 337        ring_res = RING_GET_RESPONSE(&info->ring, info->ring.rsp_prod_pvt);
 338        info->ring.rsp_prod_pvt++;
 339
 340        ring_res->rslt   = result;
 341        ring_res->rqid   = rqid;
 342
 343        if (sense_buffer != NULL &&
 344            scsi_normalize_sense(sense_buffer, VSCSIIF_SENSE_BUFFERSIZE,
 345                                 &sshdr)) {
 346                len = min_t(unsigned, 8 + sense_buffer[7],
 347                            VSCSIIF_SENSE_BUFFERSIZE);
 348                memcpy(ring_res->sense_buffer, sense_buffer, len);
 349                ring_res->sense_len = len;
 350        } else {
 351                ring_res->sense_len = 0;
 352        }
 353
 354        ring_res->residual_len = resid;
 355
 356        RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&info->ring, notify);
 357        spin_unlock_irqrestore(&info->ring_lock, flags);
 358
 359        if (notify)
 360                notify_remote_via_irq(info->irq);
 361}
 362
 363static void scsiback_do_resp_with_sense(char *sense_buffer, int32_t result,
 364                        uint32_t resid, struct vscsibk_pend *pending_req)
 365{
 366        scsiback_send_response(pending_req->info, sense_buffer, result,
 367                               resid, pending_req->rqid);
 368
 369        if (pending_req->v2p)
 370                kref_put(&pending_req->v2p->kref,
 371                         scsiback_free_translation_entry);
 372}
 373
 374static void scsiback_cmd_done(struct vscsibk_pend *pending_req)
 375{
 376        struct vscsibk_info *info = pending_req->info;
 377        unsigned char *sense_buffer;
 378        unsigned int resid;
 379        int errors;
 380
 381        sense_buffer = pending_req->sense_buffer;
 382        resid        = pending_req->se_cmd.residual_count;
 383        errors       = pending_req->result;
 384
 385        if (errors && log_print_stat)
 386                scsiback_print_status(sense_buffer, errors, pending_req);
 387
 388        scsiback_fast_flush_area(pending_req);
 389        scsiback_do_resp_with_sense(sense_buffer, errors, resid, pending_req);
 390        scsiback_put(info);
 391        /*
 392         * Drop the extra KREF_ACK reference taken by target_submit_cmd_map_sgls()
 393         * ahead of scsiback_check_stop_free() ->  transport_generic_free_cmd()
 394         * final se_cmd->cmd_kref put.
 395         */
 396        target_put_sess_cmd(&pending_req->se_cmd);
 397}
 398
 399static void scsiback_cmd_exec(struct vscsibk_pend *pending_req)
 400{
 401        struct se_cmd *se_cmd = &pending_req->se_cmd;
 402        struct se_session *sess = pending_req->v2p->tpg->tpg_nexus->tvn_se_sess;
 403        int rc;
 404
 405        scsiback_get(pending_req->info);
 406        se_cmd->tag = pending_req->rqid;
 407        rc = target_submit_cmd_map_sgls(se_cmd, sess, pending_req->cmnd,
 408                        pending_req->sense_buffer, pending_req->v2p->lun,
 409                        pending_req->data_len, 0,
 410                        pending_req->sc_data_direction, TARGET_SCF_ACK_KREF,
 411                        pending_req->sgl, pending_req->n_sg,
 412                        NULL, 0, NULL, 0);
 413        if (rc < 0) {
 414                transport_send_check_condition_and_sense(se_cmd,
 415                                TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
 416                transport_generic_free_cmd(se_cmd, 0);
 417        }
 418}
 419
 420static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 421        struct page **pg, grant_handle_t *grant, int cnt)
 422{
 423        int err, i;
 424
 425        if (!cnt)
 426                return 0;
 427
 428        err = gnttab_map_refs(map, NULL, pg, cnt);
 429        BUG_ON(err);
 430        for (i = 0; i < cnt; i++) {
 431                if (unlikely(map[i].status != GNTST_okay)) {
 432                        pr_err("invalid buffer -- could not remap it\n");
 433                        map[i].handle = SCSIBACK_INVALID_HANDLE;
 434                        err = -ENOMEM;
 435                } else {
 436                        get_page(pg[i]);
 437                }
 438                grant[i] = map[i].handle;
 439        }
 440        return err;
 441}
 442
 443static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
 444                        struct scsiif_request_segment *seg, struct page **pg,
 445                        grant_handle_t *grant, int cnt, u32 flags)
 446{
 447        int mapcount = 0, i, err = 0;
 448        struct gnttab_map_grant_ref map[VSCSI_GRANT_BATCH];
 449        struct vscsibk_info *info = pending_req->info;
 450
 451        for (i = 0; i < cnt; i++) {
 452                if (get_free_page(pg + mapcount)) {
 453                        put_free_pages(pg, mapcount);
 454                        pr_err("no grant page\n");
 455                        return -ENOMEM;
 456                }
 457                gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
 458                                  flags, seg[i].gref, info->domid);
 459                mapcount++;
 460                if (mapcount < VSCSI_GRANT_BATCH)
 461                        continue;
 462                err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 463                pg += mapcount;
 464                grant += mapcount;
 465                pending_req->n_grants += mapcount;
 466                if (err)
 467                        return err;
 468                mapcount = 0;
 469        }
 470        err = scsiback_gnttab_data_map_batch(map, pg, grant, mapcount);
 471        pending_req->n_grants += mapcount;
 472        return err;
 473}
 474
 475static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 476                                        struct vscsibk_pend *pending_req)
 477{
 478        u32 flags;
 479        int i, err, n_segs, i_seg = 0;
 480        struct page **pg;
 481        struct scsiif_request_segment *seg;
 482        unsigned long end_seg = 0;
 483        unsigned int nr_segments = (unsigned int)ring_req->nr_segments;
 484        unsigned int nr_sgl = 0;
 485        struct scatterlist *sg;
 486        grant_handle_t *grant;
 487
 488        pending_req->n_sg = 0;
 489        pending_req->n_grants = 0;
 490        pending_req->data_len = 0;
 491
 492        nr_segments &= ~VSCSIIF_SG_GRANT;
 493        if (!nr_segments)
 494                return 0;
 495
 496        if (nr_segments > VSCSIIF_SG_TABLESIZE) {
 497                pr_debug("invalid parameter nr_seg = %d\n",
 498                        ring_req->nr_segments);
 499                return -EINVAL;
 500        }
 501
 502        if (ring_req->nr_segments & VSCSIIF_SG_GRANT) {
 503                err = scsiback_gnttab_data_map_list(pending_req, ring_req->seg,
 504                        pending_req->pages, pending_req->grant_handles,
 505                        nr_segments, GNTMAP_host_map | GNTMAP_readonly);
 506                if (err)
 507                        return err;
 508                nr_sgl = nr_segments;
 509                nr_segments = 0;
 510                for (i = 0; i < nr_sgl; i++) {
 511                        n_segs = ring_req->seg[i].length /
 512                                 sizeof(struct scsiif_request_segment);
 513                        if ((unsigned)ring_req->seg[i].offset +
 514                            (unsigned)ring_req->seg[i].length > PAGE_SIZE ||
 515                            n_segs * sizeof(struct scsiif_request_segment) !=
 516                            ring_req->seg[i].length)
 517                                return -EINVAL;
 518                        nr_segments += n_segs;
 519                }
 520                if (nr_segments > SG_ALL) {
 521                        pr_debug("invalid nr_seg = %d\n", nr_segments);
 522                        return -EINVAL;
 523                }
 524        }
 525
 526        /* free of (sgl) in fast_flush_area() */
 527        pending_req->sgl = kmalloc_array(nr_segments,
 528                                        sizeof(struct scatterlist), GFP_KERNEL);
 529        if (!pending_req->sgl)
 530                return -ENOMEM;
 531
 532        sg_init_table(pending_req->sgl, nr_segments);
 533        pending_req->n_sg = nr_segments;
 534
 535        flags = GNTMAP_host_map;
 536        if (pending_req->sc_data_direction == DMA_TO_DEVICE)
 537                flags |= GNTMAP_readonly;
 538
 539        pg = pending_req->pages + nr_sgl;
 540        grant = pending_req->grant_handles + nr_sgl;
 541        if (!nr_sgl) {
 542                seg = ring_req->seg;
 543                err = scsiback_gnttab_data_map_list(pending_req, seg,
 544                        pg, grant, nr_segments, flags);
 545                if (err)
 546                        return err;
 547        } else {
 548                for (i = 0; i < nr_sgl; i++) {
 549                        seg = (struct scsiif_request_segment *)(
 550                              vaddr(pending_req, i) + ring_req->seg[i].offset);
 551                        n_segs = ring_req->seg[i].length /
 552                                 sizeof(struct scsiif_request_segment);
 553                        err = scsiback_gnttab_data_map_list(pending_req, seg,
 554                                pg, grant, n_segs, flags);
 555                        if (err)
 556                                return err;
 557                        pg += n_segs;
 558                        grant += n_segs;
 559                }
 560                end_seg = vaddr(pending_req, 0) + ring_req->seg[0].offset;
 561                seg = (struct scsiif_request_segment *)end_seg;
 562                end_seg += ring_req->seg[0].length;
 563                pg = pending_req->pages + nr_sgl;
 564        }
 565
 566        for_each_sg(pending_req->sgl, sg, nr_segments, i) {
 567                sg_set_page(sg, pg[i], seg->length, seg->offset);
 568                pending_req->data_len += seg->length;
 569                seg++;
 570                if (nr_sgl && (unsigned long)seg >= end_seg) {
 571                        i_seg++;
 572                        end_seg = vaddr(pending_req, i_seg) +
 573                                  ring_req->seg[i_seg].offset;
 574                        seg = (struct scsiif_request_segment *)end_seg;
 575                        end_seg += ring_req->seg[i_seg].length;
 576                }
 577                if (sg->offset >= PAGE_SIZE ||
 578                    sg->length > PAGE_SIZE ||
 579                    sg->offset + sg->length > PAGE_SIZE)
 580                        return -EINVAL;
 581        }
 582
 583        return 0;
 584}
 585
 586static void scsiback_disconnect(struct vscsibk_info *info)
 587{
 588        wait_event(info->waiting_to_free,
 589                atomic_read(&info->nr_unreplied_reqs) == 0);
 590
 591        unbind_from_irqhandler(info->irq, info);
 592        info->irq = 0;
 593        xenbus_unmap_ring_vfree(info->dev, info->ring.sring);
 594}
 595
 596static void scsiback_device_action(struct vscsibk_pend *pending_req,
 597        enum tcm_tmreq_table act, int tag)
 598{
 599        struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 600        struct scsiback_nexus *nexus = tpg->tpg_nexus;
 601        struct se_cmd *se_cmd = &pending_req->se_cmd;
 602        struct scsiback_tmr *tmr;
 603        u64 unpacked_lun = pending_req->v2p->lun;
 604        int rc, err = FAILED;
 605
 606        tmr = kzalloc(sizeof(struct scsiback_tmr), GFP_KERNEL);
 607        if (!tmr) {
 608                target_put_sess_cmd(se_cmd);
 609                goto err;
 610        }
 611
 612        init_waitqueue_head(&tmr->tmr_wait);
 613
 614        rc = target_submit_tmr(&pending_req->se_cmd, nexus->tvn_se_sess,
 615                               &pending_req->sense_buffer[0],
 616                               unpacked_lun, tmr, act, GFP_KERNEL,
 617                               tag, TARGET_SCF_ACK_KREF);
 618        if (rc)
 619                goto err;
 620
 621        wait_event(tmr->tmr_wait, atomic_read(&tmr->tmr_complete));
 622
 623        err = (se_cmd->se_tmr_req->response == TMR_FUNCTION_COMPLETE) ?
 624                SUCCESS : FAILED;
 625
 626        scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 627        transport_generic_free_cmd(&pending_req->se_cmd, 1);
 628        return;
 629err:
 630        if (tmr)
 631                kfree(tmr);
 632        scsiback_do_resp_with_sense(NULL, err, 0, pending_req);
 633}
 634
 635/*
 636  Perform virtual to physical translation
 637*/
 638static struct v2p_entry *scsiback_do_translation(struct vscsibk_info *info,
 639                        struct ids_tuple *v)
 640{
 641        struct v2p_entry *entry;
 642        struct list_head *head = &(info->v2p_entry_lists);
 643        unsigned long flags;
 644
 645        spin_lock_irqsave(&info->v2p_lock, flags);
 646        list_for_each_entry(entry, head, l) {
 647                if ((entry->v.chn == v->chn) &&
 648                    (entry->v.tgt == v->tgt) &&
 649                    (entry->v.lun == v->lun)) {
 650                        kref_get(&entry->kref);
 651                        goto out;
 652                }
 653        }
 654        entry = NULL;
 655
 656out:
 657        spin_unlock_irqrestore(&info->v2p_lock, flags);
 658        return entry;
 659}
 660
 661static struct vscsibk_pend *scsiback_get_pend_req(struct vscsiif_back_ring *ring,
 662                                struct v2p_entry *v2p)
 663{
 664        struct scsiback_tpg *tpg = v2p->tpg;
 665        struct scsiback_nexus *nexus = tpg->tpg_nexus;
 666        struct se_session *se_sess = nexus->tvn_se_sess;
 667        struct vscsibk_pend *req;
 668        int tag, i;
 669
 670        tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
 671        if (tag < 0) {
 672                pr_err("Unable to obtain tag for vscsiif_request\n");
 673                return ERR_PTR(-ENOMEM);
 674        }
 675
 676        req = &((struct vscsibk_pend *)se_sess->sess_cmd_map)[tag];
 677        memset(req, 0, sizeof(*req));
 678        req->se_cmd.map_tag = tag;
 679
 680        for (i = 0; i < VSCSI_MAX_GRANTS; i++)
 681                req->grant_handles[i] = SCSIBACK_INVALID_HANDLE;
 682
 683        return req;
 684}
 685
 686static struct vscsibk_pend *prepare_pending_reqs(struct vscsibk_info *info,
 687                                struct vscsiif_back_ring *ring,
 688                                struct vscsiif_request *ring_req)
 689{
 690        struct vscsibk_pend *pending_req;
 691        struct v2p_entry *v2p;
 692        struct ids_tuple vir;
 693
 694        /* request range check from frontend */
 695        if ((ring_req->sc_data_direction != DMA_BIDIRECTIONAL) &&
 696                (ring_req->sc_data_direction != DMA_TO_DEVICE) &&
 697                (ring_req->sc_data_direction != DMA_FROM_DEVICE) &&
 698                (ring_req->sc_data_direction != DMA_NONE)) {
 699                pr_debug("invalid parameter data_dir = %d\n",
 700                        ring_req->sc_data_direction);
 701                return ERR_PTR(-EINVAL);
 702        }
 703        if (ring_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
 704                pr_debug("invalid parameter cmd_len = %d\n",
 705                        ring_req->cmd_len);
 706                return ERR_PTR(-EINVAL);
 707        }
 708
 709        vir.chn = ring_req->channel;
 710        vir.tgt = ring_req->id;
 711        vir.lun = ring_req->lun;
 712
 713        v2p = scsiback_do_translation(info, &vir);
 714        if (!v2p) {
 715                pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
 716                         vir.chn, vir.tgt, vir.lun);
 717                return ERR_PTR(-ENODEV);
 718        }
 719
 720        pending_req = scsiback_get_pend_req(ring, v2p);
 721        if (IS_ERR(pending_req)) {
 722                kref_put(&v2p->kref, scsiback_free_translation_entry);
 723                return ERR_PTR(-ENOMEM);
 724        }
 725        pending_req->rqid = ring_req->rqid;
 726        pending_req->info = info;
 727        pending_req->v2p = v2p;
 728        pending_req->sc_data_direction = ring_req->sc_data_direction;
 729        pending_req->cmd_len = ring_req->cmd_len;
 730        memcpy(pending_req->cmnd, ring_req->cmnd, pending_req->cmd_len);
 731
 732        return pending_req;
 733}
 734
 735static int scsiback_do_cmd_fn(struct vscsibk_info *info)
 736{
 737        struct vscsiif_back_ring *ring = &info->ring;
 738        struct vscsiif_request ring_req;
 739        struct vscsibk_pend *pending_req;
 740        RING_IDX rc, rp;
 741        int more_to_do;
 742        uint32_t result;
 743
 744        rc = ring->req_cons;
 745        rp = ring->sring->req_prod;
 746        rmb();  /* guest system is accessing ring, too */
 747
 748        if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
 749                rc = ring->rsp_prod_pvt;
 750                pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 751                           info->domid, rp, rc, rp - rc);
 752                info->ring_error = 1;
 753                return 0;
 754        }
 755
 756        while ((rc != rp)) {
 757                if (RING_REQUEST_CONS_OVERFLOW(ring, rc))
 758                        break;
 759
 760                RING_COPY_REQUEST(ring, rc, &ring_req);
 761                ring->req_cons = ++rc;
 762
 763                pending_req = prepare_pending_reqs(info, ring, &ring_req);
 764                if (IS_ERR(pending_req)) {
 765                        switch (PTR_ERR(pending_req)) {
 766                        case -ENODEV:
 767                                result = DID_NO_CONNECT;
 768                                break;
 769                        default:
 770                                result = DRIVER_ERROR;
 771                                break;
 772                        }
 773                        scsiback_send_response(info, NULL, result << 24, 0,
 774                                               ring_req.rqid);
 775                        return 1;
 776                }
 777
 778                switch (ring_req.act) {
 779                case VSCSIIF_ACT_SCSI_CDB:
 780                        if (scsiback_gnttab_data_map(&ring_req, pending_req)) {
 781                                scsiback_fast_flush_area(pending_req);
 782                                scsiback_do_resp_with_sense(NULL,
 783                                                DRIVER_ERROR << 24, 0, pending_req);
 784                                transport_generic_free_cmd(&pending_req->se_cmd, 0);
 785                        } else {
 786                                scsiback_cmd_exec(pending_req);
 787                        }
 788                        break;
 789                case VSCSIIF_ACT_SCSI_ABORT:
 790                        scsiback_device_action(pending_req, TMR_ABORT_TASK,
 791                                ring_req.ref_rqid);
 792                        break;
 793                case VSCSIIF_ACT_SCSI_RESET:
 794                        scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
 795                        break;
 796                default:
 797                        pr_err_ratelimited("invalid request\n");
 798                        scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24, 0,
 799                                                    pending_req);
 800                        transport_generic_free_cmd(&pending_req->se_cmd, 0);
 801                        break;
 802                }
 803
 804                /* Yield point for this unbounded loop. */
 805                cond_resched();
 806        }
 807
 808        RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do);
 809        return more_to_do;
 810}
 811
 812static irqreturn_t scsiback_irq_fn(int irq, void *dev_id)
 813{
 814        struct vscsibk_info *info = dev_id;
 815
 816        if (info->ring_error)
 817                return IRQ_HANDLED;
 818
 819        while (scsiback_do_cmd_fn(info))
 820                cond_resched();
 821
 822        return IRQ_HANDLED;
 823}
 824
 825static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 826                        evtchn_port_t evtchn)
 827{
 828        void *area;
 829        struct vscsiif_sring *sring;
 830        int err;
 831
 832        if (info->irq)
 833                return -1;
 834
 835        err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 836        if (err)
 837                return err;
 838
 839        sring = (struct vscsiif_sring *)area;
 840        BACK_RING_INIT(&info->ring, sring, PAGE_SIZE);
 841
 842        err = bind_interdomain_evtchn_to_irq(info->domid, evtchn);
 843        if (err < 0)
 844                goto unmap_page;
 845
 846        info->irq = err;
 847
 848        err = request_threaded_irq(info->irq, NULL, scsiback_irq_fn,
 849                                   IRQF_ONESHOT, "vscsiif-backend", info);
 850        if (err)
 851                goto free_irq;
 852
 853        return 0;
 854
 855free_irq:
 856        unbind_from_irqhandler(info->irq, info);
 857        info->irq = 0;
 858unmap_page:
 859        xenbus_unmap_ring_vfree(info->dev, area);
 860
 861        return err;
 862}
 863
 864static int scsiback_map(struct vscsibk_info *info)
 865{
 866        struct xenbus_device *dev = info->dev;
 867        unsigned int ring_ref, evtchn;
 868        int err;
 869
 870        err = xenbus_gather(XBT_NIL, dev->otherend,
 871                        "ring-ref", "%u", &ring_ref,
 872                        "event-channel", "%u", &evtchn, NULL);
 873        if (err) {
 874                xenbus_dev_fatal(dev, err, "reading %s ring", dev->otherend);
 875                return err;
 876        }
 877
 878        return scsiback_init_sring(info, ring_ref, evtchn);
 879}
 880
 881/*
 882  Check for a translation entry being present
 883*/
 884static struct v2p_entry *scsiback_chk_translation_entry(
 885        struct vscsibk_info *info, struct ids_tuple *v)
 886{
 887        struct list_head *head = &(info->v2p_entry_lists);
 888        struct v2p_entry *entry;
 889
 890        list_for_each_entry(entry, head, l)
 891                if ((entry->v.chn == v->chn) &&
 892                    (entry->v.tgt == v->tgt) &&
 893                    (entry->v.lun == v->lun))
 894                        return entry;
 895
 896        return NULL;
 897}
 898
 899/*
 900  Add a new translation entry
 901*/
 902static int scsiback_add_translation_entry(struct vscsibk_info *info,
 903                                          char *phy, struct ids_tuple *v)
 904{
 905        int err = 0;
 906        struct v2p_entry *new;
 907        unsigned long flags;
 908        char *lunp;
 909        unsigned long long unpacked_lun;
 910        struct se_lun *se_lun;
 911        struct scsiback_tpg *tpg_entry, *tpg = NULL;
 912        char *error = "doesn't exist";
 913
 914        lunp = strrchr(phy, ':');
 915        if (!lunp) {
 916                pr_err("illegal format of physical device %s\n", phy);
 917                return -EINVAL;
 918        }
 919        *lunp = 0;
 920        lunp++;
 921        err = kstrtoull(lunp, 10, &unpacked_lun);
 922        if (err < 0) {
 923                pr_err("lun number not valid: %s\n", lunp);
 924                return err;
 925        }
 926
 927        mutex_lock(&scsiback_mutex);
 928        list_for_each_entry(tpg_entry, &scsiback_list, tv_tpg_list) {
 929                if (!strcmp(phy, tpg_entry->tport->tport_name) ||
 930                    !strcmp(phy, tpg_entry->param_alias)) {
 931                        mutex_lock(&tpg_entry->se_tpg.tpg_lun_mutex);
 932                        hlist_for_each_entry(se_lun, &tpg_entry->se_tpg.tpg_lun_hlist, link) {
 933                                if (se_lun->unpacked_lun == unpacked_lun) {
 934                                        if (!tpg_entry->tpg_nexus)
 935                                                error = "nexus undefined";
 936                                        else
 937                                                tpg = tpg_entry;
 938                                        break;
 939                                }
 940                        }
 941                        mutex_unlock(&tpg_entry->se_tpg.tpg_lun_mutex);
 942                        break;
 943                }
 944        }
 945        if (tpg) {
 946                mutex_lock(&tpg->tv_tpg_mutex);
 947                tpg->tv_tpg_fe_count++;
 948                mutex_unlock(&tpg->tv_tpg_mutex);
 949        }
 950        mutex_unlock(&scsiback_mutex);
 951
 952        if (!tpg) {
 953                pr_err("%s:%llu %s\n", phy, unpacked_lun, error);
 954                return -ENODEV;
 955        }
 956
 957        new = kmalloc(sizeof(struct v2p_entry), GFP_KERNEL);
 958        if (new == NULL) {
 959                err = -ENOMEM;
 960                goto out_free;
 961        }
 962
 963        spin_lock_irqsave(&info->v2p_lock, flags);
 964
 965        /* Check double assignment to identical virtual ID */
 966        if (scsiback_chk_translation_entry(info, v)) {
 967                pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 968                err = -EEXIST;
 969                goto out;
 970        }
 971
 972        /* Create a new translation entry and add to the list */
 973        kref_init(&new->kref);
 974        new->v = *v;
 975        new->tpg = tpg;
 976        new->lun = unpacked_lun;
 977        list_add_tail(&new->l, &info->v2p_entry_lists);
 978
 979out:
 980        spin_unlock_irqrestore(&info->v2p_lock, flags);
 981
 982out_free:
 983        if (err) {
 984                mutex_lock(&tpg->tv_tpg_mutex);
 985                tpg->tv_tpg_fe_count--;
 986                mutex_unlock(&tpg->tv_tpg_mutex);
 987                kfree(new);
 988        }
 989
 990        return err;
 991}
 992
 993static void __scsiback_del_translation_entry(struct v2p_entry *entry)
 994{
 995        list_del(&entry->l);
 996        kref_put(&entry->kref, scsiback_free_translation_entry);
 997}
 998
 999/*
1000  Delete the translation entry specified
1001*/
1002static int scsiback_del_translation_entry(struct vscsibk_info *info,
1003                                          struct ids_tuple *v)
1004{
1005        struct v2p_entry *entry;
1006        unsigned long flags;
1007        int ret = 0;
1008
1009        spin_lock_irqsave(&info->v2p_lock, flags);
1010        /* Find out the translation entry specified */
1011        entry = scsiback_chk_translation_entry(info, v);
1012        if (entry)
1013                __scsiback_del_translation_entry(entry);
1014        else
1015                ret = -ENOENT;
1016
1017        spin_unlock_irqrestore(&info->v2p_lock, flags);
1018        return ret;
1019}
1020
1021static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
1022                                char *phy, struct ids_tuple *vir, int try)
1023{
1024        struct v2p_entry *entry;
1025        unsigned long flags;
1026
1027        if (try) {
1028                spin_lock_irqsave(&info->v2p_lock, flags);
1029                entry = scsiback_chk_translation_entry(info, vir);
1030                spin_unlock_irqrestore(&info->v2p_lock, flags);
1031                if (entry)
1032                        return;
1033        }
1034        if (!scsiback_add_translation_entry(info, phy, vir)) {
1035                if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1036                                  "%d", XenbusStateInitialised)) {
1037                        pr_err("xenbus_printf error %s\n", state);
1038                        scsiback_del_translation_entry(info, vir);
1039                }
1040        } else if (!try) {
1041                xenbus_printf(XBT_NIL, info->dev->nodename, state,
1042                              "%d", XenbusStateClosed);
1043        }
1044}
1045
1046static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
1047                                struct ids_tuple *vir)
1048{
1049        if (!scsiback_del_translation_entry(info, vir)) {
1050                if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
1051                                  "%d", XenbusStateClosed))
1052                        pr_err("xenbus_printf error %s\n", state);
1053        }
1054}
1055
1056#define VSCSIBACK_OP_ADD_OR_DEL_LUN     1
1057#define VSCSIBACK_OP_UPDATEDEV_STATE    2
1058
1059static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
1060                                     char *ent)
1061{
1062        int err;
1063        struct ids_tuple vir;
1064        char *val;
1065        int device_state;
1066        char phy[VSCSI_NAMELEN];
1067        char str[64];
1068        char state[64];
1069        struct xenbus_device *dev = info->dev;
1070
1071        /* read status */
1072        snprintf(state, sizeof(state), "vscsi-devs/%s/state", ent);
1073        err = xenbus_scanf(XBT_NIL, dev->nodename, state, "%u", &device_state);
1074        if (XENBUS_EXIST_ERR(err))
1075                return;
1076
1077        /* physical SCSI device */
1078        snprintf(str, sizeof(str), "vscsi-devs/%s/p-dev", ent);
1079        val = xenbus_read(XBT_NIL, dev->nodename, str, NULL);
1080        if (IS_ERR(val)) {
1081                xenbus_printf(XBT_NIL, dev->nodename, state,
1082                              "%d", XenbusStateClosed);
1083                return;
1084        }
1085        strlcpy(phy, val, VSCSI_NAMELEN);
1086        kfree(val);
1087
1088        /* virtual SCSI device */
1089        snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", ent);
1090        err = xenbus_scanf(XBT_NIL, dev->nodename, str, "%u:%u:%u:%u",
1091                           &vir.hst, &vir.chn, &vir.tgt, &vir.lun);
1092        if (XENBUS_EXIST_ERR(err)) {
1093                xenbus_printf(XBT_NIL, dev->nodename, state,
1094                              "%d", XenbusStateClosed);
1095                return;
1096        }
1097
1098        switch (op) {
1099        case VSCSIBACK_OP_ADD_OR_DEL_LUN:
1100                switch (device_state) {
1101                case XenbusStateInitialising:
1102                        scsiback_do_add_lun(info, state, phy, &vir, 0);
1103                        break;
1104                case XenbusStateConnected:
1105                        scsiback_do_add_lun(info, state, phy, &vir, 1);
1106                        break;
1107                case XenbusStateClosing:
1108                        scsiback_do_del_lun(info, state, &vir);
1109                        break;
1110                default:
1111                        break;
1112                }
1113                break;
1114
1115        case VSCSIBACK_OP_UPDATEDEV_STATE:
1116                if (device_state == XenbusStateInitialised) {
1117                        /* modify vscsi-devs/dev-x/state */
1118                        if (xenbus_printf(XBT_NIL, dev->nodename, state,
1119                                          "%d", XenbusStateConnected)) {
1120                                pr_err("xenbus_printf error %s\n", str);
1121                                scsiback_del_translation_entry(info, &vir);
1122                                xenbus_printf(XBT_NIL, dev->nodename, state,
1123                                              "%d", XenbusStateClosed);
1124                        }
1125                }
1126                break;
1127        /* When it is necessary, processing is added here. */
1128        default:
1129                break;
1130        }
1131}
1132
1133static void scsiback_do_lun_hotplug(struct vscsibk_info *info, int op)
1134{
1135        int i;
1136        char **dir;
1137        unsigned int ndir = 0;
1138
1139        dir = xenbus_directory(XBT_NIL, info->dev->nodename, "vscsi-devs",
1140                               &ndir);
1141        if (IS_ERR(dir))
1142                return;
1143
1144        for (i = 0; i < ndir; i++)
1145                scsiback_do_1lun_hotplug(info, op, dir[i]);
1146
1147        kfree(dir);
1148}
1149
1150static void scsiback_frontend_changed(struct xenbus_device *dev,
1151                                        enum xenbus_state frontend_state)
1152{
1153        struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1154
1155        switch (frontend_state) {
1156        case XenbusStateInitialising:
1157                break;
1158
1159        case XenbusStateInitialised:
1160                if (scsiback_map(info))
1161                        break;
1162
1163                scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1164                xenbus_switch_state(dev, XenbusStateConnected);
1165                break;
1166
1167        case XenbusStateConnected:
1168                scsiback_do_lun_hotplug(info, VSCSIBACK_OP_UPDATEDEV_STATE);
1169
1170                if (dev->state == XenbusStateConnected)
1171                        break;
1172
1173                xenbus_switch_state(dev, XenbusStateConnected);
1174                break;
1175
1176        case XenbusStateClosing:
1177                if (info->irq)
1178                        scsiback_disconnect(info);
1179
1180                xenbus_switch_state(dev, XenbusStateClosing);
1181                break;
1182
1183        case XenbusStateClosed:
1184                xenbus_switch_state(dev, XenbusStateClosed);
1185                if (xenbus_dev_is_online(dev))
1186                        break;
1187                /* fall through if not online */
1188        case XenbusStateUnknown:
1189                device_unregister(&dev->dev);
1190                break;
1191
1192        case XenbusStateReconfiguring:
1193                scsiback_do_lun_hotplug(info, VSCSIBACK_OP_ADD_OR_DEL_LUN);
1194                xenbus_switch_state(dev, XenbusStateReconfigured);
1195
1196                break;
1197
1198        default:
1199                xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
1200                                        frontend_state);
1201                break;
1202        }
1203}
1204
1205/*
1206  Release the translation entry specfied
1207*/
1208static void scsiback_release_translation_entry(struct vscsibk_info *info)
1209{
1210        struct v2p_entry *entry, *tmp;
1211        struct list_head *head = &(info->v2p_entry_lists);
1212        unsigned long flags;
1213
1214        spin_lock_irqsave(&info->v2p_lock, flags);
1215
1216        list_for_each_entry_safe(entry, tmp, head, l)
1217                __scsiback_del_translation_entry(entry);
1218
1219        spin_unlock_irqrestore(&info->v2p_lock, flags);
1220}
1221
1222static int scsiback_remove(struct xenbus_device *dev)
1223{
1224        struct vscsibk_info *info = dev_get_drvdata(&dev->dev);
1225
1226        if (info->irq)
1227                scsiback_disconnect(info);
1228
1229        scsiback_release_translation_entry(info);
1230
1231        dev_set_drvdata(&dev->dev, NULL);
1232
1233        return 0;
1234}
1235
1236static int scsiback_probe(struct xenbus_device *dev,
1237                           const struct xenbus_device_id *id)
1238{
1239        int err;
1240
1241        struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
1242                                            GFP_KERNEL);
1243
1244        pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
1245
1246        if (!info) {
1247                xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
1248                return -ENOMEM;
1249        }
1250        info->dev = dev;
1251        dev_set_drvdata(&dev->dev, info);
1252
1253        info->domid = dev->otherend_id;
1254        spin_lock_init(&info->ring_lock);
1255        info->ring_error = 0;
1256        atomic_set(&info->nr_unreplied_reqs, 0);
1257        init_waitqueue_head(&info->waiting_to_free);
1258        info->dev = dev;
1259        info->irq = 0;
1260        INIT_LIST_HEAD(&info->v2p_entry_lists);
1261        spin_lock_init(&info->v2p_lock);
1262
1263        err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
1264                            SG_ALL);
1265        if (err)
1266                xenbus_dev_error(dev, err, "writing feature-sg-grant");
1267
1268        err = xenbus_switch_state(dev, XenbusStateInitWait);
1269        if (err)
1270                goto fail;
1271
1272        return 0;
1273
1274fail:
1275        pr_warn("%s failed\n", __func__);
1276        scsiback_remove(dev);
1277
1278        return err;
1279}
1280
1281static char *scsiback_dump_proto_id(struct scsiback_tport *tport)
1282{
1283        switch (tport->tport_proto_id) {
1284        case SCSI_PROTOCOL_SAS:
1285                return "SAS";
1286        case SCSI_PROTOCOL_FCP:
1287                return "FCP";
1288        case SCSI_PROTOCOL_ISCSI:
1289                return "iSCSI";
1290        default:
1291                break;
1292        }
1293
1294        return "Unknown";
1295}
1296
1297static char *scsiback_get_fabric_wwn(struct se_portal_group *se_tpg)
1298{
1299        struct scsiback_tpg *tpg = container_of(se_tpg,
1300                                struct scsiback_tpg, se_tpg);
1301        struct scsiback_tport *tport = tpg->tport;
1302
1303        return &tport->tport_name[0];
1304}
1305
1306static u16 scsiback_get_tag(struct se_portal_group *se_tpg)
1307{
1308        struct scsiback_tpg *tpg = container_of(se_tpg,
1309                                struct scsiback_tpg, se_tpg);
1310        return tpg->tport_tpgt;
1311}
1312
1313static struct se_wwn *
1314scsiback_make_tport(struct target_fabric_configfs *tf,
1315                     struct config_group *group,
1316                     const char *name)
1317{
1318        struct scsiback_tport *tport;
1319        char *ptr;
1320        u64 wwpn = 0;
1321        int off = 0;
1322
1323        tport = kzalloc(sizeof(struct scsiback_tport), GFP_KERNEL);
1324        if (!tport)
1325                return ERR_PTR(-ENOMEM);
1326
1327        tport->tport_wwpn = wwpn;
1328        /*
1329         * Determine the emulated Protocol Identifier and Target Port Name
1330         * based on the incoming configfs directory name.
1331         */
1332        ptr = strstr(name, "naa.");
1333        if (ptr) {
1334                tport->tport_proto_id = SCSI_PROTOCOL_SAS;
1335                goto check_len;
1336        }
1337        ptr = strstr(name, "fc.");
1338        if (ptr) {
1339                tport->tport_proto_id = SCSI_PROTOCOL_FCP;
1340                off = 3; /* Skip over "fc." */
1341                goto check_len;
1342        }
1343        ptr = strstr(name, "iqn.");
1344        if (ptr) {
1345                tport->tport_proto_id = SCSI_PROTOCOL_ISCSI;
1346                goto check_len;
1347        }
1348
1349        pr_err("Unable to locate prefix for emulated Target Port: %s\n", name);
1350        kfree(tport);
1351        return ERR_PTR(-EINVAL);
1352
1353check_len:
1354        if (strlen(name) >= VSCSI_NAMELEN) {
1355                pr_err("Emulated %s Address: %s, exceeds max: %d\n", name,
1356                        scsiback_dump_proto_id(tport), VSCSI_NAMELEN);
1357                kfree(tport);
1358                return ERR_PTR(-EINVAL);
1359        }
1360        snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
1361
1362        pr_debug("Allocated emulated Target %s Address: %s\n",
1363                 scsiback_dump_proto_id(tport), name);
1364
1365        return &tport->tport_wwn;
1366}
1367
1368static void scsiback_drop_tport(struct se_wwn *wwn)
1369{
1370        struct scsiback_tport *tport = container_of(wwn,
1371                                struct scsiback_tport, tport_wwn);
1372
1373        pr_debug("Deallocating emulated Target %s Address: %s\n",
1374                 scsiback_dump_proto_id(tport), tport->tport_name);
1375
1376        kfree(tport);
1377}
1378
1379static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
1380{
1381        return 1;
1382}
1383
1384static int scsiback_check_stop_free(struct se_cmd *se_cmd)
1385{
1386        return transport_generic_free_cmd(se_cmd, 0);
1387}
1388
1389static void scsiback_release_cmd(struct se_cmd *se_cmd)
1390{
1391        struct se_session *se_sess = se_cmd->se_sess;
1392        struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
1393
1394        if (se_tmr && se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB) {
1395                struct scsiback_tmr *tmr = se_tmr->fabric_tmr_ptr;
1396                kfree(tmr);
1397        }
1398
1399        percpu_ida_free(&se_sess->sess_tag_pool, se_cmd->map_tag);
1400}
1401
1402static u32 scsiback_sess_get_index(struct se_session *se_sess)
1403{
1404        return 0;
1405}
1406
1407static int scsiback_write_pending(struct se_cmd *se_cmd)
1408{
1409        /* Go ahead and process the write immediately */
1410        target_execute_cmd(se_cmd);
1411
1412        return 0;
1413}
1414
1415static int scsiback_write_pending_status(struct se_cmd *se_cmd)
1416{
1417        return 0;
1418}
1419
1420static void scsiback_set_default_node_attrs(struct se_node_acl *nacl)
1421{
1422}
1423
1424static int scsiback_get_cmd_state(struct se_cmd *se_cmd)
1425{
1426        return 0;
1427}
1428
1429static int scsiback_queue_data_in(struct se_cmd *se_cmd)
1430{
1431        struct vscsibk_pend *pending_req = container_of(se_cmd,
1432                                struct vscsibk_pend, se_cmd);
1433
1434        pending_req->result = SAM_STAT_GOOD;
1435        scsiback_cmd_done(pending_req);
1436        return 0;
1437}
1438
1439static int scsiback_queue_status(struct se_cmd *se_cmd)
1440{
1441        struct vscsibk_pend *pending_req = container_of(se_cmd,
1442                                struct vscsibk_pend, se_cmd);
1443
1444        if (se_cmd->sense_buffer &&
1445            ((se_cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
1446             (se_cmd->se_cmd_flags & SCF_EMULATED_TASK_SENSE)))
1447                pending_req->result = (DRIVER_SENSE << 24) |
1448                                      SAM_STAT_CHECK_CONDITION;
1449        else
1450                pending_req->result = se_cmd->scsi_status;
1451
1452        scsiback_cmd_done(pending_req);
1453        return 0;
1454}
1455
1456static void scsiback_queue_tm_rsp(struct se_cmd *se_cmd)
1457{
1458        struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
1459        struct scsiback_tmr *tmr = se_tmr->fabric_tmr_ptr;
1460
1461        atomic_set(&tmr->tmr_complete, 1);
1462        wake_up(&tmr->tmr_wait);
1463}
1464
1465static void scsiback_aborted_task(struct se_cmd *se_cmd)
1466{
1467}
1468
1469static ssize_t scsiback_tpg_param_alias_show(struct config_item *item,
1470                                             char *page)
1471{
1472        struct se_portal_group *se_tpg = param_to_tpg(item);
1473        struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1474                                                se_tpg);
1475        ssize_t rb;
1476
1477        mutex_lock(&tpg->tv_tpg_mutex);
1478        rb = snprintf(page, PAGE_SIZE, "%s\n", tpg->param_alias);
1479        mutex_unlock(&tpg->tv_tpg_mutex);
1480
1481        return rb;
1482}
1483
1484static ssize_t scsiback_tpg_param_alias_store(struct config_item *item,
1485                                              const char *page, size_t count)
1486{
1487        struct se_portal_group *se_tpg = param_to_tpg(item);
1488        struct scsiback_tpg *tpg = container_of(se_tpg, struct scsiback_tpg,
1489                                                se_tpg);
1490        int len;
1491
1492        if (strlen(page) >= VSCSI_NAMELEN) {
1493                pr_err("param alias: %s, exceeds max: %d\n", page,
1494                        VSCSI_NAMELEN);
1495                return -EINVAL;
1496        }
1497
1498        mutex_lock(&tpg->tv_tpg_mutex);
1499        len = snprintf(tpg->param_alias, VSCSI_NAMELEN, "%s", page);
1500        if (tpg->param_alias[len - 1] == '\n')
1501                tpg->param_alias[len - 1] = '\0';
1502        mutex_unlock(&tpg->tv_tpg_mutex);
1503
1504        return count;
1505}
1506
1507CONFIGFS_ATTR(scsiback_tpg_param_, alias);
1508
1509static struct configfs_attribute *scsiback_param_attrs[] = {
1510        &scsiback_tpg_param_attr_alias,
1511        NULL,
1512};
1513
1514static int scsiback_alloc_sess_cb(struct se_portal_group *se_tpg,
1515                                  struct se_session *se_sess, void *p)
1516{
1517        struct scsiback_tpg *tpg = container_of(se_tpg,
1518                                struct scsiback_tpg, se_tpg);
1519
1520        tpg->tpg_nexus = p;
1521        return 0;
1522}
1523
1524static int scsiback_make_nexus(struct scsiback_tpg *tpg,
1525                                const char *name)
1526{
1527        struct scsiback_nexus *tv_nexus;
1528        int ret = 0;
1529
1530        mutex_lock(&tpg->tv_tpg_mutex);
1531        if (tpg->tpg_nexus) {
1532                pr_debug("tpg->tpg_nexus already exists\n");
1533                ret = -EEXIST;
1534                goto out_unlock;
1535        }
1536
1537        tv_nexus = kzalloc(sizeof(struct scsiback_nexus), GFP_KERNEL);
1538        if (!tv_nexus) {
1539                ret = -ENOMEM;
1540                goto out_unlock;
1541        }
1542
1543        tv_nexus->tvn_se_sess = target_alloc_session(&tpg->se_tpg,
1544                                                     VSCSI_DEFAULT_SESSION_TAGS,
1545                                                     sizeof(struct vscsibk_pend),
1546                                                     TARGET_PROT_NORMAL, name,
1547                                                     tv_nexus, scsiback_alloc_sess_cb);
1548        if (IS_ERR(tv_nexus->tvn_se_sess)) {
1549                kfree(tv_nexus);
1550                ret = -ENOMEM;
1551                goto out_unlock;
1552        }
1553
1554out_unlock:
1555        mutex_unlock(&tpg->tv_tpg_mutex);
1556        return ret;
1557}
1558
1559static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
1560{
1561        struct se_session *se_sess;
1562        struct scsiback_nexus *tv_nexus;
1563
1564        mutex_lock(&tpg->tv_tpg_mutex);
1565        tv_nexus = tpg->tpg_nexus;
1566        if (!tv_nexus) {
1567                mutex_unlock(&tpg->tv_tpg_mutex);
1568                return -ENODEV;
1569        }
1570
1571        se_sess = tv_nexus->tvn_se_sess;
1572        if (!se_sess) {
1573                mutex_unlock(&tpg->tv_tpg_mutex);
1574                return -ENODEV;
1575        }
1576
1577        if (tpg->tv_tpg_port_count != 0) {
1578                mutex_unlock(&tpg->tv_tpg_mutex);
1579                pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG port count: %d\n",
1580                        tpg->tv_tpg_port_count);
1581                return -EBUSY;
1582        }
1583
1584        if (tpg->tv_tpg_fe_count != 0) {
1585                mutex_unlock(&tpg->tv_tpg_mutex);
1586                pr_err("Unable to remove xen-pvscsi I_T Nexus with active TPG frontend count: %d\n",
1587                        tpg->tv_tpg_fe_count);
1588                return -EBUSY;
1589        }
1590
1591        pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
1592                scsiback_dump_proto_id(tpg->tport),
1593                tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1594
1595        /*
1596         * Release the SCSI I_T Nexus to the emulated xen-pvscsi Target Port
1597         */
1598        transport_deregister_session(tv_nexus->tvn_se_sess);
1599        tpg->tpg_nexus = NULL;
1600        mutex_unlock(&tpg->tv_tpg_mutex);
1601
1602        kfree(tv_nexus);
1603        return 0;
1604}
1605
1606static ssize_t scsiback_tpg_nexus_show(struct config_item *item, char *page)
1607{
1608        struct se_portal_group *se_tpg = to_tpg(item);
1609        struct scsiback_tpg *tpg = container_of(se_tpg,
1610                                struct scsiback_tpg, se_tpg);
1611        struct scsiback_nexus *tv_nexus;
1612        ssize_t ret;
1613
1614        mutex_lock(&tpg->tv_tpg_mutex);
1615        tv_nexus = tpg->tpg_nexus;
1616        if (!tv_nexus) {
1617                mutex_unlock(&tpg->tv_tpg_mutex);
1618                return -ENODEV;
1619        }
1620        ret = snprintf(page, PAGE_SIZE, "%s\n",
1621                        tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
1622        mutex_unlock(&tpg->tv_tpg_mutex);
1623
1624        return ret;
1625}
1626
1627static ssize_t scsiback_tpg_nexus_store(struct config_item *item,
1628                const char *page, size_t count)
1629{
1630        struct se_portal_group *se_tpg = to_tpg(item);
1631        struct scsiback_tpg *tpg = container_of(se_tpg,
1632                                struct scsiback_tpg, se_tpg);
1633        struct scsiback_tport *tport_wwn = tpg->tport;
1634        unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
1635        int ret;
1636        /*
1637         * Shutdown the active I_T nexus if 'NULL' is passed.
1638         */
1639        if (!strncmp(page, "NULL", 4)) {
1640                ret = scsiback_drop_nexus(tpg);
1641                return (!ret) ? count : ret;
1642        }
1643        /*
1644         * Otherwise make sure the passed virtual Initiator port WWN matches
1645         * the fabric protocol_id set in scsiback_make_tport(), and call
1646         * scsiback_make_nexus().
1647         */
1648        if (strlen(page) >= VSCSI_NAMELEN) {
1649                pr_err("Emulated NAA Sas Address: %s, exceeds max: %d\n",
1650                        page, VSCSI_NAMELEN);
1651                return -EINVAL;
1652        }
1653        snprintf(&i_port[0], VSCSI_NAMELEN, "%s", page);
1654
1655        ptr = strstr(i_port, "naa.");
1656        if (ptr) {
1657                if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_SAS) {
1658                        pr_err("Passed SAS Initiator Port %s does not match target port protoid: %s\n",
1659                                i_port, scsiback_dump_proto_id(tport_wwn));
1660                        return -EINVAL;
1661                }
1662                port_ptr = &i_port[0];
1663                goto check_newline;
1664        }
1665        ptr = strstr(i_port, "fc.");
1666        if (ptr) {
1667                if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_FCP) {
1668                        pr_err("Passed FCP Initiator Port %s does not match target port protoid: %s\n",
1669                                i_port, scsiback_dump_proto_id(tport_wwn));
1670                        return -EINVAL;
1671                }
1672                port_ptr = &i_port[3]; /* Skip over "fc." */
1673                goto check_newline;
1674        }
1675        ptr = strstr(i_port, "iqn.");
1676        if (ptr) {
1677                if (tport_wwn->tport_proto_id != SCSI_PROTOCOL_ISCSI) {
1678                        pr_err("Passed iSCSI Initiator Port %s does not match target port protoid: %s\n",
1679                                i_port, scsiback_dump_proto_id(tport_wwn));
1680                        return -EINVAL;
1681                }
1682                port_ptr = &i_port[0];
1683                goto check_newline;
1684        }
1685        pr_err("Unable to locate prefix for emulated Initiator Port: %s\n",
1686                i_port);
1687        return -EINVAL;
1688        /*
1689         * Clear any trailing newline for the NAA WWN
1690         */
1691check_newline:
1692        if (i_port[strlen(i_port) - 1] == '\n')
1693                i_port[strlen(i_port) - 1] = '\0';
1694
1695        ret = scsiback_make_nexus(tpg, port_ptr);
1696        if (ret < 0)
1697                return ret;
1698
1699        return count;
1700}
1701
1702CONFIGFS_ATTR(scsiback_tpg_, nexus);
1703
1704static struct configfs_attribute *scsiback_tpg_attrs[] = {
1705        &scsiback_tpg_attr_nexus,
1706        NULL,
1707};
1708
1709static ssize_t
1710scsiback_wwn_version_show(struct config_item *item, char *page)
1711{
1712        return sprintf(page, "xen-pvscsi fabric module %s on %s/%s on "
1713                UTS_RELEASE"\n",
1714                VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1715}
1716
1717CONFIGFS_ATTR_RO(scsiback_wwn_, version);
1718
1719static struct configfs_attribute *scsiback_wwn_attrs[] = {
1720        &scsiback_wwn_attr_version,
1721        NULL,
1722};
1723
1724static char *scsiback_get_fabric_name(void)
1725{
1726        return "xen-pvscsi";
1727}
1728
1729static int scsiback_port_link(struct se_portal_group *se_tpg,
1730                               struct se_lun *lun)
1731{
1732        struct scsiback_tpg *tpg = container_of(se_tpg,
1733                                struct scsiback_tpg, se_tpg);
1734
1735        mutex_lock(&tpg->tv_tpg_mutex);
1736        tpg->tv_tpg_port_count++;
1737        mutex_unlock(&tpg->tv_tpg_mutex);
1738
1739        return 0;
1740}
1741
1742static void scsiback_port_unlink(struct se_portal_group *se_tpg,
1743                                  struct se_lun *lun)
1744{
1745        struct scsiback_tpg *tpg = container_of(se_tpg,
1746                                struct scsiback_tpg, se_tpg);
1747
1748        mutex_lock(&tpg->tv_tpg_mutex);
1749        tpg->tv_tpg_port_count--;
1750        mutex_unlock(&tpg->tv_tpg_mutex);
1751}
1752
1753static struct se_portal_group *
1754scsiback_make_tpg(struct se_wwn *wwn,
1755                   struct config_group *group,
1756                   const char *name)
1757{
1758        struct scsiback_tport *tport = container_of(wwn,
1759                        struct scsiback_tport, tport_wwn);
1760
1761        struct scsiback_tpg *tpg;
1762        u16 tpgt;
1763        int ret;
1764
1765        if (strstr(name, "tpgt_") != name)
1766                return ERR_PTR(-EINVAL);
1767        ret = kstrtou16(name + 5, 10, &tpgt);
1768        if (ret)
1769                return ERR_PTR(ret);
1770
1771        tpg = kzalloc(sizeof(struct scsiback_tpg), GFP_KERNEL);
1772        if (!tpg)
1773                return ERR_PTR(-ENOMEM);
1774
1775        mutex_init(&tpg->tv_tpg_mutex);
1776        INIT_LIST_HEAD(&tpg->tv_tpg_list);
1777        INIT_LIST_HEAD(&tpg->info_list);
1778        tpg->tport = tport;
1779        tpg->tport_tpgt = tpgt;
1780
1781        ret = core_tpg_register(wwn, &tpg->se_tpg, tport->tport_proto_id);
1782        if (ret < 0) {
1783                kfree(tpg);
1784                return NULL;
1785        }
1786        mutex_lock(&scsiback_mutex);
1787        list_add_tail(&tpg->tv_tpg_list, &scsiback_list);
1788        mutex_unlock(&scsiback_mutex);
1789
1790        return &tpg->se_tpg;
1791}
1792
1793static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
1794{
1795        struct scsiback_tpg *tpg = container_of(se_tpg,
1796                                struct scsiback_tpg, se_tpg);
1797
1798        mutex_lock(&scsiback_mutex);
1799        list_del(&tpg->tv_tpg_list);
1800        mutex_unlock(&scsiback_mutex);
1801        /*
1802         * Release the virtual I_T Nexus for this xen-pvscsi TPG
1803         */
1804        scsiback_drop_nexus(tpg);
1805        /*
1806         * Deregister the se_tpg from TCM.
1807         */
1808        core_tpg_deregister(se_tpg);
1809        kfree(tpg);
1810}
1811
1812static int scsiback_check_true(struct se_portal_group *se_tpg)
1813{
1814        return 1;
1815}
1816
1817static int scsiback_check_false(struct se_portal_group *se_tpg)
1818{
1819        return 0;
1820}
1821
1822static const struct target_core_fabric_ops scsiback_ops = {
1823        .module                         = THIS_MODULE,
1824        .name                           = "xen-pvscsi",
1825        .get_fabric_name                = scsiback_get_fabric_name,
1826        .tpg_get_wwn                    = scsiback_get_fabric_wwn,
1827        .tpg_get_tag                    = scsiback_get_tag,
1828        .tpg_check_demo_mode            = scsiback_check_true,
1829        .tpg_check_demo_mode_cache      = scsiback_check_true,
1830        .tpg_check_demo_mode_write_protect = scsiback_check_false,
1831        .tpg_check_prod_mode_write_protect = scsiback_check_false,
1832        .tpg_get_inst_index             = scsiback_tpg_get_inst_index,
1833        .check_stop_free                = scsiback_check_stop_free,
1834        .release_cmd                    = scsiback_release_cmd,
1835        .sess_get_index                 = scsiback_sess_get_index,
1836        .sess_get_initiator_sid         = NULL,
1837        .write_pending                  = scsiback_write_pending,
1838        .write_pending_status           = scsiback_write_pending_status,
1839        .set_default_node_attributes    = scsiback_set_default_node_attrs,
1840        .get_cmd_state                  = scsiback_get_cmd_state,
1841        .queue_data_in                  = scsiback_queue_data_in,
1842        .queue_status                   = scsiback_queue_status,
1843        .queue_tm_rsp                   = scsiback_queue_tm_rsp,
1844        .aborted_task                   = scsiback_aborted_task,
1845        /*
1846         * Setup callers for generic logic in target_core_fabric_configfs.c
1847         */
1848        .fabric_make_wwn                = scsiback_make_tport,
1849        .fabric_drop_wwn                = scsiback_drop_tport,
1850        .fabric_make_tpg                = scsiback_make_tpg,
1851        .fabric_drop_tpg                = scsiback_drop_tpg,
1852        .fabric_post_link               = scsiback_port_link,
1853        .fabric_pre_unlink              = scsiback_port_unlink,
1854
1855        .tfc_wwn_attrs                  = scsiback_wwn_attrs,
1856        .tfc_tpg_base_attrs             = scsiback_tpg_attrs,
1857        .tfc_tpg_param_attrs            = scsiback_param_attrs,
1858};
1859
1860static const struct xenbus_device_id scsiback_ids[] = {
1861        { "vscsi" },
1862        { "" }
1863};
1864
1865static struct xenbus_driver scsiback_driver = {
1866        .ids                    = scsiback_ids,
1867        .probe                  = scsiback_probe,
1868        .remove                 = scsiback_remove,
1869        .otherend_changed       = scsiback_frontend_changed
1870};
1871
1872static int __init scsiback_init(void)
1873{
1874        int ret;
1875
1876        if (!xen_domain())
1877                return -ENODEV;
1878
1879        pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
1880                 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
1881
1882        ret = xenbus_register_backend(&scsiback_driver);
1883        if (ret)
1884                goto out;
1885
1886        ret = target_register_template(&scsiback_ops);
1887        if (ret)
1888                goto out_unregister_xenbus;
1889
1890        return 0;
1891
1892out_unregister_xenbus:
1893        xenbus_unregister_driver(&scsiback_driver);
1894out:
1895        pr_err("%s: error %d\n", __func__, ret);
1896        return ret;
1897}
1898
1899static void __exit scsiback_exit(void)
1900{
1901        struct page *page;
1902
1903        while (free_pages_num) {
1904                if (get_free_page(&page))
1905                        BUG();
1906                gnttab_free_pages(1, &page);
1907        }
1908        target_unregister_template(&scsiback_ops);
1909        xenbus_unregister_driver(&scsiback_driver);
1910}
1911
1912module_init(scsiback_init);
1913module_exit(scsiback_exit);
1914
1915MODULE_DESCRIPTION("Xen SCSI backend driver");
1916MODULE_LICENSE("Dual BSD/GPL");
1917MODULE_ALIAS("xen-backend:vscsi");
1918MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");
1919