drivers/scsi/virtio_scsi.c

   1 /*
   2  * Virtio SCSI HBA driver
   3  *
   4  * Copyright IBM Corp. 2010
   5  * Copyright Red Hat, Inc. 2011
   6  *
   7  * Authors:
   8  *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>
   9  *  Paolo Bonzini   <pbonzini@redhat.com>
  10  *
  11  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  12  * See the COPYING file in the top-level directory.
  13  *
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/mempool.h>
  19 #include <linux/virtio.h>
  20 #include <linux/virtio_ids.h>
  21 #include <linux/virtio_config.h>
  22 #include <linux/virtio_scsi.h>
  23 #include <scsi/scsi_host.h>
  24 #include <scsi/scsi_device.h>
  25 #include <scsi/scsi_cmnd.h>
  26
  27 #define VIRTIO_SCSI_MEMPOOL_SZ 64
  28 #define VIRTIO_SCSI_EVENT_LEN 8
  29
  30 /* Command queue element */
  31 struct virtio_scsi_cmd {
  32         struct scsi_cmnd *sc;
  33         struct completion *comp;
  34         union {
  35                 struct virtio_scsi_cmd_req       cmd;
  36                 struct virtio_scsi_ctrl_tmf_req  tmf;
  37                 struct virtio_scsi_ctrl_an_req   an;
  38         } req;
  39         union {
  40                 struct virtio_scsi_cmd_resp      cmd;
  41                 struct virtio_scsi_ctrl_tmf_resp tmf;
  42                 struct virtio_scsi_ctrl_an_resp  an;
  43                 struct virtio_scsi_event         evt;
  44         } resp;
  45 } ____cacheline_aligned_in_smp;
  46
  47 struct virtio_scsi_event_node {
  48         struct virtio_scsi *vscsi;
  49         struct virtio_scsi_event event;
  50         struct work_struct work;
  51 };
  52
  53 struct virtio_scsi_vq {
  54         /* Protects vq */
  55         spinlock_t vq_lock;
  56
  57         struct virtqueue *vq;
  58 };
  59
  60 /* Per-target queue state */
  61 struct virtio_scsi_target_state {
  62         /* Protects sg.  Lock hierarchy is tgt_lock -> vq_lock.  */
  63         spinlock_t tgt_lock;
  64
  65         /* For sglist construction when adding commands to the virtqueue.  */
  66         struct scatterlist sg[];
  67 };
  68
  69 /* Driver instance state */
  70 struct virtio_scsi {
  71         struct virtio_device *vdev;
  72
  73         struct virtio_scsi_vq ctrl_vq;
  74         struct virtio_scsi_vq event_vq;
  75         struct virtio_scsi_vq req_vq;
  76
  77         /* Get some buffers ready for event vq */
  78         struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
  79
  80         struct virtio_scsi_target_state *tgt[];
  81 };
  82
  83 static struct kmem_cache *virtscsi_cmd_cache;
  84 static mempool_t *virtscsi_cmd_pool;
  85
  86 static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
  87 {
  88         return vdev->priv;
  89 }
  90
  91 static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
  92 {
  93         if (!resid)
  94                 return;
  95
  96         if (!scsi_bidi_cmnd(sc)) {
  97                 scsi_set_resid(sc, resid);
  98                 return;
  99         }
 100
 101         scsi_in(sc)->resid = min(resid, scsi_in(sc)->length);
 102         scsi_out(sc)->resid = resid - scsi_in(sc)->resid;
 103 }
 104
 105 /**
 106  * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
 107  *
 108  * Called with vq_lock held.
 109  */
 110 static void virtscsi_complete_cmd(void *buf)
 111 {
 112         struct virtio_scsi_cmd *cmd = buf;
 113         struct scsi_cmnd *sc = cmd->sc;
 114         struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
 115
 116         dev_dbg(&sc->device->sdev_gendev,
 117                 "cmd %p response %u status %#02x sense_len %u\n",
 118                 sc, resp->response, resp->status, resp->sense_len);
 119
 120         sc->result = resp->status;
 121         virtscsi_compute_resid(sc, resp->resid);
 122         switch (resp->response) {
 123         case VIRTIO_SCSI_S_OK:
 124                 set_host_byte(sc, DID_OK);
 125                 break;
 126         case VIRTIO_SCSI_S_OVERRUN:
 127                 set_host_byte(sc, DID_ERROR);
 128                 break;
 129         case VIRTIO_SCSI_S_ABORTED:
 130                 set_host_byte(sc, DID_ABORT);
 131                 break;
 132         case VIRTIO_SCSI_S_BAD_TARGET:
 133                 set_host_byte(sc, DID_BAD_TARGET);
 134                 break;
 135         case VIRTIO_SCSI_S_RESET:
 136                 set_host_byte(sc, DID_RESET);
 137                 break;
 138         case VIRTIO_SCSI_S_BUSY:
 139                 set_host_byte(sc, DID_BUS_BUSY);
 140                 break;
 141         case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
 142                 set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
 143                 break;
 144         case VIRTIO_SCSI_S_TARGET_FAILURE:
 145                 set_host_byte(sc, DID_TARGET_FAILURE);
 146                 break;
 147         case VIRTIO_SCSI_S_NEXUS_FAILURE:
 148                 set_host_byte(sc, DID_NEXUS_FAILURE);
 149                 break;
 150         default:
 151                 scmd_printk(KERN_WARNING, sc, "Unknown response %d",
 152                             resp->response);
 153                 /* fall through */
 154         case VIRTIO_SCSI_S_FAILURE:
 155                 set_host_byte(sc, DID_ERROR);
 156                 break;
 157         }
 158
 159         WARN_ON(resp->sense_len > VIRTIO_SCSI_SENSE_SIZE);
 160         if (sc->sense_buffer) {
 161                 memcpy(sc->sense_buffer, resp->sense,
 162                        min_t(u32, resp->sense_len, VIRTIO_SCSI_SENSE_SIZE));
 163                 if (resp->sense_len)
 164                         set_driver_byte(sc, DRIVER_SENSE);
 165         }
 166
 167         mempool_free(cmd, virtscsi_cmd_pool);
 168         sc->scsi_done(sc);
 169 }
 170
 171 static void virtscsi_vq_done(struct virtqueue *vq, void (*fn)(void *buf))
 172 {
 173         void *buf;
 174         unsigned int len;
 175
 176         do {
 177                 virtqueue_disable_cb(vq);
 178                 while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
 179                         fn(buf);
 180         } while (!virtqueue_enable_cb(vq));
 181 }
 182
 183 static void virtscsi_req_done(struct virtqueue *vq)
 184 {
 185         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 186         struct virtio_scsi *vscsi = shost_priv(sh);
 187         unsigned long flags;
 188
 189         spin_lock_irqsave(&vscsi->req_vq.vq_lock, flags);
 190         virtscsi_vq_done(vq, virtscsi_complete_cmd);
 191         spin_unlock_irqrestore(&vscsi->req_vq.vq_lock, flags);
 192 };
 193
 194 static void virtscsi_complete_free(void *buf)
 195 {
 196         struct virtio_scsi_cmd *cmd = buf;
 197
 198         if (cmd->comp)
 199                 complete_all(cmd->comp);
 200         else
 201                 mempool_free(cmd, virtscsi_cmd_pool);
 202 }
 203
 204 static void virtscsi_ctrl_done(struct virtqueue *vq)
 205 {
 206         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 207         struct virtio_scsi *vscsi = shost_priv(sh);
 208         unsigned long flags;
 209
 210         spin_lock_irqsave(&vscsi->ctrl_vq.vq_lock, flags);
 211         virtscsi_vq_done(vq, virtscsi_complete_free);
 212         spin_unlock_irqrestore(&vscsi->ctrl_vq.vq_lock, flags);
 213 };
 214
 215 static int virtscsi_kick_event(struct virtio_scsi *vscsi,
 216                                struct virtio_scsi_event_node *event_node)
 217 {
 218         int ret;
 219         struct scatterlist sg;
 220         unsigned long flags;
 221
 222         sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
 223
 224         spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
 225
 226         ret = virtqueue_add_buf(vscsi->event_vq.vq, &sg, 0, 1, event_node, GFP_ATOMIC);
 227         if (ret >= 0)
 228                 virtqueue_kick(vscsi->event_vq.vq);
 229
 230         spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 231
 232         return ret;
 233 }
 234
 235 static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
 236 {
 237         int i;
 238
 239         for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
 240                 vscsi->event_list[i].vscsi = vscsi;
 241                 virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
 242         }
 243
 244         return 0;
 245 }
 246
 247 static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
 248 {
 249         int i;
 250
 251         for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
 252                 cancel_work_sync(&vscsi->event_list[i].work);
 253 }
 254
 255 static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
 256                                                 struct virtio_scsi_event *event)
 257 {
 258         struct scsi_device *sdev;
 259         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 260         unsigned int target = event->lun[1];
 261         unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 262
 263         switch (event->reason) {
 264         case VIRTIO_SCSI_EVT_RESET_RESCAN:
 265                 scsi_add_device(shost, 0, target, lun);
 266                 break;
 267         case VIRTIO_SCSI_EVT_RESET_REMOVED:
 268                 sdev = scsi_device_lookup(shost, 0, target, lun);
 269                 if (sdev) {
 270                         scsi_remove_device(sdev);
 271                         scsi_device_put(sdev);
 272                 } else {
 273                         pr_err("SCSI device %d 0 %d %d not found\n",
 274                                 shost->host_no, target, lun);
 275                 }
 276                 break;
 277         default:
 278                 pr_info("Unsupport virtio scsi event reason %x\n", event->reason);
 279         }
 280 }
 281
 282 static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
 283                                          struct virtio_scsi_event *event)
 284 {
 285         struct scsi_device *sdev;
 286         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 287         unsigned int target = event->lun[1];
 288         unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 289         u8 asc = event->reason & 255;
 290         u8 ascq = event->reason >> 8;
 291
 292         sdev = scsi_device_lookup(shost, 0, target, lun);
 293         if (!sdev) {
 294                 pr_err("SCSI device %d 0 %d %d not found\n",
 295                         shost->host_no, target, lun);
 296                 return;
 297         }
 298
 299         /* Handle "Parameters changed", "Mode parameters changed", and
 300            "Capacity data has changed".  */
 301         if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
 302                 scsi_rescan_device(&sdev->sdev_gendev);
 303
 304         scsi_device_put(sdev);
 305 }
 306
 307 static void virtscsi_handle_event(struct work_struct *work)
 308 {
 309         struct virtio_scsi_event_node *event_node =
 310                 container_of(work, struct virtio_scsi_event_node, work);
 311         struct virtio_scsi *vscsi = event_node->vscsi;
 312         struct virtio_scsi_event *event = &event_node->event;
 313
 314         if (event->event & VIRTIO_SCSI_T_EVENTS_MISSED) {
 315                 event->event &= ~VIRTIO_SCSI_T_EVENTS_MISSED;
 316                 scsi_scan_host(virtio_scsi_host(vscsi->vdev));
 317         }
 318
 319         switch (event->event) {
 320         case VIRTIO_SCSI_T_NO_EVENT:
 321                 break;
 322         case VIRTIO_SCSI_T_TRANSPORT_RESET:
 323                 virtscsi_handle_transport_reset(vscsi, event);
 324                 break;
 325         case VIRTIO_SCSI_T_PARAM_CHANGE:
 326                 virtscsi_handle_param_change(vscsi, event);
 327                 break;
 328         default:
 329                 pr_err("Unsupport virtio scsi event %x\n", event->event);
 330         }
 331         virtscsi_kick_event(vscsi, event_node);
 332 }
 333
 334 static void virtscsi_complete_event(void *buf)
 335 {
 336         struct virtio_scsi_event_node *event_node = buf;
 337
 338         INIT_WORK(&event_node->work, virtscsi_handle_event);
 339         schedule_work(&event_node->work);
 340 }
 341
 342 static void virtscsi_event_done(struct virtqueue *vq)
 343 {
 344         struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 345         struct virtio_scsi *vscsi = shost_priv(sh);
 346         unsigned long flags;
 347
 348         spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
 349         virtscsi_vq_done(vq, virtscsi_complete_event);
 350         spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 351 };
 352
 353 static void virtscsi_map_sgl(struct scatterlist *sg, unsigned int *p_idx,
 354                              struct scsi_data_buffer *sdb)
 355 {
 356         struct sg_table *table = &sdb->table;
 357         struct scatterlist *sg_elem;
 358         unsigned int idx = *p_idx;
 359         int i;
 360
 361         for_each_sg(table->sgl, sg_elem, table->nents, i)
 362                 sg[idx++] = *sg_elem;
 363
 364         *p_idx = idx;
 365 }
 366
 367 /**
 368  * virtscsi_map_cmd - map a scsi_cmd to a virtqueue scatterlist
 369  * @vscsi       : virtio_scsi state
 370  * @cmd         : command structure
 371  * @out_num     : number of read-only elements
 372  * @in_num      : number of write-only elements
 373  * @req_size    : size of the request buffer
 374  * @resp_size   : size of the response buffer
 375  *
 376  * Called with tgt_lock held.
 377  */
 378 static void virtscsi_map_cmd(struct virtio_scsi_target_state *tgt,
 379                              struct virtio_scsi_cmd *cmd,
 380                              unsigned *out_num, unsigned *in_num,
 381                              size_t req_size, size_t resp_size)
 382 {
 383         struct scsi_cmnd *sc = cmd->sc;
 384         struct scatterlist *sg = tgt->sg;
 385         unsigned int idx = 0;
 386
 387         /* Request header.  */
 388         sg_set_buf(&sg[idx++], &cmd->req, req_size);
 389
 390         /* Data-out buffer.  */
 391         if (sc && sc->sc_data_direction != DMA_FROM_DEVICE)
 392                 virtscsi_map_sgl(sg, &idx, scsi_out(sc));
 393
 394         *out_num = idx;
 395
 396         /* Response header.  */
 397         sg_set_buf(&sg[idx++], &cmd->resp, resp_size);
 398
 399         /* Data-in buffer */
 400         if (sc && sc->sc_data_direction != DMA_TO_DEVICE)
 401                 virtscsi_map_sgl(sg, &idx, scsi_in(sc));
 402
 403         *in_num = idx - *out_num;
 404 }
 405
 406 static int virtscsi_kick_cmd(struct virtio_scsi_target_state *tgt,
 407                              struct virtio_scsi_vq *vq,
 408                              struct virtio_scsi_cmd *cmd,
 409                              size_t req_size, size_t resp_size, gfp_t gfp)
 410 {
 411         unsigned int out_num, in_num;
 412         unsigned long flags;
 413         int ret;
 414
 415         spin_lock_irqsave(&tgt->tgt_lock, flags);
 416         virtscsi_map_cmd(tgt, cmd, &out_num, &in_num, req_size, resp_size);
 417
 418         spin_lock(&vq->vq_lock);
 419         ret = virtqueue_add_buf(vq->vq, tgt->sg, out_num, in_num, cmd, gfp);
 420         spin_unlock(&tgt->tgt_lock);
 421         if (ret >= 0)
 422                 ret = virtqueue_kick_prepare(vq->vq);
 423
 424         spin_unlock_irqrestore(&vq->vq_lock, flags);
 425
 426         if (ret > 0)
 427                 virtqueue_notify(vq->vq);
 428         return ret;
 429 }
 430
 431 static int virtscsi_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
 432 {
 433         struct virtio_scsi *vscsi = shost_priv(sh);
 434         struct virtio_scsi_target_state *tgt = vscsi->tgt[sc->device->id];
 435         struct virtio_scsi_cmd *cmd;
 436         int ret;
 437
 438         struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 439         BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
 440
 441         /* TODO: check feature bit and fail if unsupported?  */
 442         BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
 443
 444         dev_dbg(&sc->device->sdev_gendev,
 445                 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
 446
 447         ret = SCSI_MLQUEUE_HOST_BUSY;
 448         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC);
 449         if (!cmd)
 450                 goto out;
 451
 452         memset(cmd, 0, sizeof(*cmd));
 453         cmd->sc = sc;
 454         cmd->req.cmd = (struct virtio_scsi_cmd_req){
 455                 .lun[0] = 1,
 456                 .lun[1] = sc->device->id,
 457                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 458                 .lun[3] = sc->device->lun & 0xff,
 459                 .tag = (unsigned long)sc,
 460                 .task_attr = VIRTIO_SCSI_S_SIMPLE,
 461                 .prio = 0,
 462                 .crn = 0,
 463         };
 464
 465         BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
 466         memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
 467
 468         if (virtscsi_kick_cmd(tgt, &vscsi->req_vq, cmd,
 469                               sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
 470                               GFP_ATOMIC) >= 0)
 471                 ret = 0;
 472
 473 out:
 474         return ret;
 475 }
 476
 477 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 478 {
 479         DECLARE_COMPLETION_ONSTACK(comp);
 480         struct virtio_scsi_target_state *tgt = vscsi->tgt[cmd->sc->device->id];
 481         int ret = FAILED;
 482
 483         cmd->comp = &comp;
 484         if (virtscsi_kick_cmd(tgt, &vscsi->ctrl_vq, cmd,
 485                               sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
 486                               GFP_NOIO) < 0)
 487                 goto out;
 488
 489         wait_for_completion(&comp);
 490         if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
 491             cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
 492                 ret = SUCCESS;
 493
 494 out:
 495         mempool_free(cmd, virtscsi_cmd_pool);
 496         return ret;
 497 }
 498
 499 static int virtscsi_device_reset(struct scsi_cmnd *sc)
 500 {
 501         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 502         struct virtio_scsi_cmd *cmd;
 503
 504         sdev_printk(KERN_INFO, sc->device, "device reset\n");
 505         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 506         if (!cmd)
 507                 return FAILED;
 508
 509         memset(cmd, 0, sizeof(*cmd));
 510         cmd->sc = sc;
 511         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 512                 .type = VIRTIO_SCSI_T_TMF,
 513                 .subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET,
 514                 .lun[0] = 1,
 515                 .lun[1] = sc->device->id,
 516                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 517                 .lun[3] = sc->device->lun & 0xff,
 518         };
 519         return virtscsi_tmf(vscsi, cmd);
 520 }
 521
 522 static int virtscsi_abort(struct scsi_cmnd *sc)
 523 {
 524         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 525         struct virtio_scsi_cmd *cmd;
 526
 527         scmd_printk(KERN_INFO, sc, "abort\n");
 528         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 529         if (!cmd)
 530                 return FAILED;
 531
 532         memset(cmd, 0, sizeof(*cmd));
 533         cmd->sc = sc;
 534         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 535                 .type = VIRTIO_SCSI_T_TMF,
 536                 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
 537                 .lun[0] = 1,
 538                 .lun[1] = sc->device->id,
 539                 .lun[2] = (sc->device->lun >> 8) | 0x40,
 540                 .lun[3] = sc->device->lun & 0xff,
 541                 .tag = (unsigned long)sc,
 542         };
 543         return virtscsi_tmf(vscsi, cmd);
 544 }
 545
 546 static struct scsi_host_template virtscsi_host_template = {
 547         .module = THIS_MODULE,
 548         .name = "Virtio SCSI HBA",
 549         .proc_name = "virtio_scsi",
 550         .queuecommand = virtscsi_queuecommand,
 551         .this_id = -1,
 552         .eh_abort_handler = virtscsi_abort,
 553         .eh_device_reset_handler = virtscsi_device_reset,
 554
 555         .can_queue = 1024,
 556         .dma_boundary = UINT_MAX,
 557         .use_clustering = ENABLE_CLUSTERING,
 558 };
 559
 560 #define virtscsi_config_get(vdev, fld) \
 561         ({ \
 562                 typeof(((struct virtio_scsi_config *)0)->fld) __val; \
 563                 vdev->config->get(vdev, \
 564                                   offsetof(struct virtio_scsi_config, fld), \
 565                                   &__val, sizeof(__val)); \
 566                 __val; \
 567         })
 568
 569 #define virtscsi_config_set(vdev, fld, val) \
 570         (void)({ \
 571                 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
 572                 vdev->config->set(vdev, \
 573                                   offsetof(struct virtio_scsi_config, fld), \
 574                                   &__val, sizeof(__val)); \
 575         })
 576
 577 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
 578                              struct virtqueue *vq)
 579 {
 580         spin_lock_init(&virtscsi_vq->vq_lock);
 581         virtscsi_vq->vq = vq;
 582 }
 583
 584 static struct virtio_scsi_target_state *virtscsi_alloc_tgt(
 585         struct virtio_device *vdev, int sg_elems)
 586 {
 587         struct virtio_scsi_target_state *tgt;
 588         gfp_t gfp_mask = GFP_KERNEL;
 589
 590         /* We need extra sg elements at head and tail.  */
 591         tgt = kmalloc(sizeof(*tgt) + sizeof(tgt->sg[0]) * (sg_elems + 2),
 592                       gfp_mask);
 593
 594         if (!tgt)
 595                 return NULL;
 596
 597         spin_lock_init(&tgt->tgt_lock);
 598         sg_init_table(tgt->sg, sg_elems + 2);
 599         return tgt;
 600 }
 601
 602 static void virtscsi_scan(struct virtio_device *vdev)
 603 {
 604         struct Scsi_Host *shost = (struct Scsi_Host *)vdev->priv;
 605
 606         scsi_scan_host(shost);
 607 }
 608
 609 static void virtscsi_remove_vqs(struct virtio_device *vdev)
 610 {
 611         struct Scsi_Host *sh = virtio_scsi_host(vdev);
 612         struct virtio_scsi *vscsi = shost_priv(sh);
 613         u32 i, num_targets;
 614
 615         /* Stop all the virtqueues. */
 616         vdev->config->reset(vdev);
 617
 618         num_targets = sh->max_id;
 619         for (i = 0; i < num_targets; i++) {
 620                 kfree(vscsi->tgt[i]);
 621                 vscsi->tgt[i] = NULL;
 622         }
 623
 624         vdev->config->del_vqs(vdev);
 625 }
 626
 627 static int virtscsi_init(struct virtio_device *vdev,
 628                          struct virtio_scsi *vscsi, int num_targets)
 629 {
 630         int err;
 631         struct virtqueue *vqs[3];
 632         u32 i, sg_elems;
 633
 634         vq_callback_t *callbacks[] = {
 635                 virtscsi_ctrl_done,
 636                 virtscsi_event_done,
 637                 virtscsi_req_done
 638         };
 639         const char *names[] = {
 640                 "control",
 641                 "event",
 642                 "request"
 643         };
 644
 645         /* Discover virtqueues and write information to configuration.  */
 646         err = vdev->config->find_vqs(vdev, 3, vqs, callbacks, names);
 647         if (err)
 648                 return err;
 649
 650         virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
 651         virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
 652         virtscsi_init_vq(&vscsi->req_vq, vqs[2]);
 653
 654         virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 655         virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 656
 657         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 658                 virtscsi_kick_event_all(vscsi);
 659
 660         /* We need to know how many segments before we allocate.  */
 661         sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 662
 663         for (i = 0; i < num_targets; i++) {
 664                 vscsi->tgt[i] = virtscsi_alloc_tgt(vdev, sg_elems);
 665                 if (!vscsi->tgt[i]) {
 666                         err = -ENOMEM;
 667                         goto out;
 668                 }
 669         }
 670         err = 0;
 671
 672 out:
 673         if (err)
 674                 virtscsi_remove_vqs(vdev);
 675         return err;
 676 }
 677
 678 static int __devinit virtscsi_probe(struct virtio_device *vdev)
 679 {
 680         struct Scsi_Host *shost;
 681         struct virtio_scsi *vscsi;
 682         int err;
 683         u32 sg_elems, num_targets;
 684         u32 cmd_per_lun;
 685
 686         /* Allocate memory and link the structs together.  */
 687         num_targets = virtscsi_config_get(vdev, max_target) + 1;
 688         shost = scsi_host_alloc(&virtscsi_host_template,
 689                 sizeof(*vscsi)
 690                 + num_targets * sizeof(struct virtio_scsi_target_state));
 691
 692         if (!shost)
 693                 return -ENOMEM;
 694
 695         sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 696         shost->sg_tablesize = sg_elems;
 697         vscsi = shost_priv(shost);
 698         vscsi->vdev = vdev;
 699         vdev->priv = shost;
 700
 701         err = virtscsi_init(vdev, vscsi, num_targets);
 702         if (err)
 703                 goto virtscsi_init_failed;
 704
 705         cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
 706         shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
 707         shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
 708
 709         /* LUNs > 256 are reported with format 1, so they go in the range
 710          * 16640-32767.
 711          */
 712         shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
 713         shost->max_id = num_targets;
 714         shost->max_channel = 0;
 715         shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
 716         err = scsi_add_host(shost, &vdev->dev);
 717         if (err)
 718                 goto scsi_add_host_failed;
 719         /*
 720          * scsi_scan_host() happens in virtscsi_scan() via virtio_driver->scan()
 721          * after VIRTIO_CONFIG_S_DRIVER_OK has been set..
 722          */
 723         return 0;
 724
 725 scsi_add_host_failed:
 726         vdev->config->del_vqs(vdev);
 727 virtscsi_init_failed:
 728         scsi_host_put(shost);
 729         return err;
 730 }
 731
 732 static void __devexit virtscsi_remove(struct virtio_device *vdev)
 733 {
 734         struct Scsi_Host *shost = virtio_scsi_host(vdev);
 735         struct virtio_scsi *vscsi = shost_priv(shost);
 736
 737         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 738                 virtscsi_cancel_event_work(vscsi);
 739
 740         scsi_remove_host(shost);
 741
 742         virtscsi_remove_vqs(vdev);
 743         scsi_host_put(shost);
 744 }
 745
 746 #ifdef CONFIG_PM
 747 static int virtscsi_freeze(struct virtio_device *vdev)
 748 {
 749         virtscsi_remove_vqs(vdev);
 750         return 0;
 751 }
 752
 753 static int virtscsi_restore(struct virtio_device *vdev)
 754 {
 755         struct Scsi_Host *sh = virtio_scsi_host(vdev);
 756         struct virtio_scsi *vscsi = shost_priv(sh);
 757
 758         return virtscsi_init(vdev, vscsi, sh->max_id);
 759 }
 760 #endif
 761
 762 static struct virtio_device_id id_table[] = {
 763         { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
 764         { 0 },
 765 };
 766
 767 static unsigned int features[] = {
 768         VIRTIO_SCSI_F_HOTPLUG,
 769         VIRTIO_SCSI_F_CHANGE,
 770 };
 771
 772 static struct virtio_driver virtio_scsi_driver = {
 773         .feature_table = features,
 774         .feature_table_size = ARRAY_SIZE(features),
 775         .driver.name = KBUILD_MODNAME,
 776         .driver.owner = THIS_MODULE,
 777         .id_table = id_table,
 778         .probe = virtscsi_probe,
 779         .scan = virtscsi_scan,
 780 #ifdef CONFIG_PM
 781         .freeze = virtscsi_freeze,
 782         .restore = virtscsi_restore,
 783 #endif
 784         .remove = __devexit_p(virtscsi_remove),
 785 };
 786
 787 static int __init init(void)
 788 {
 789         int ret = -ENOMEM;
 790
 791         virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
 792         if (!virtscsi_cmd_cache) {
 793                 printk(KERN_ERR "kmem_cache_create() for "
 794                                 "virtscsi_cmd_cache failed\n");
 795                 goto error;
 796         }
 797
 798
 799         virtscsi_cmd_pool =
 800                 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
 801                                          virtscsi_cmd_cache);
 802         if (!virtscsi_cmd_pool) {
 803                 printk(KERN_ERR "mempool_create() for"
 804                                 "virtscsi_cmd_pool failed\n");
 805                 goto error;
 806         }
 807         ret = register_virtio_driver(&virtio_scsi_driver);
 808         if (ret < 0)
 809                 goto error;
 810
 811         return 0;
 812
 813 error:
 814         if (virtscsi_cmd_pool) {
 815                 mempool_destroy(virtscsi_cmd_pool);
 816                 virtscsi_cmd_pool = NULL;
 817         }
 818         if (virtscsi_cmd_cache) {
 819                 kmem_cache_destroy(virtscsi_cmd_cache);
 820                 virtscsi_cmd_cache = NULL;
 821         }
 822         return ret;
 823 }
 824
 825 static void __exit fini(void)
 826 {
 827         unregister_virtio_driver(&virtio_scsi_driver);
 828         mempool_destroy(virtscsi_cmd_pool);
 829         kmem_cache_destroy(virtscsi_cmd_cache);
 830 }
 831 module_init(init);
 832 module_exit(fini);
 833
 834 MODULE_DEVICE_TABLE(virtio, id_table);
 835 MODULE_DESCRIPTION("Virtio SCSI HBA driver");
 836 MODULE_LICENSE("GPL");