linux/drivers/scsi/virtio_scsi.c
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   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 */
  31struct 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
  47struct virtio_scsi_event_node {
  48        struct virtio_scsi *vscsi;
  49        struct virtio_scsi_event event;
  50        struct work_struct work;
  51};
  52
  53struct virtio_scsi_vq {
  54        /* Protects vq */
  55        spinlock_t vq_lock;
  56
  57        struct virtqueue *vq;
  58};
  59
  60/* Per-target queue state */
  61struct 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 */
  70struct 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
  83static struct kmem_cache *virtscsi_cmd_cache;
  84static mempool_t *virtscsi_cmd_pool;
  85
  86static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
  87{
  88        return vdev->priv;
  89}
  90
  91static 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 */
 110static 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
 171static 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
 183static 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
 194static 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
 204static 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
 215static 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
 235static 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
 247static 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
 255static 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
 282static void virtscsi_handle_event(struct work_struct *work)
 283{
 284        struct virtio_scsi_event_node *event_node =
 285                container_of(work, struct virtio_scsi_event_node, work);
 286        struct virtio_scsi *vscsi = event_node->vscsi;
 287        struct virtio_scsi_event *event = &event_node->event;
 288
 289        if (event->event & VIRTIO_SCSI_T_EVENTS_MISSED) {
 290                event->event &= ~VIRTIO_SCSI_T_EVENTS_MISSED;
 291                scsi_scan_host(virtio_scsi_host(vscsi->vdev));
 292        }
 293
 294        switch (event->event) {
 295        case VIRTIO_SCSI_T_NO_EVENT:
 296                break;
 297        case VIRTIO_SCSI_T_TRANSPORT_RESET:
 298                virtscsi_handle_transport_reset(vscsi, event);
 299                break;
 300        default:
 301                pr_err("Unsupport virtio scsi event %x\n", event->event);
 302        }
 303        virtscsi_kick_event(vscsi, event_node);
 304}
 305
 306static void virtscsi_complete_event(void *buf)
 307{
 308        struct virtio_scsi_event_node *event_node = buf;
 309
 310        INIT_WORK(&event_node->work, virtscsi_handle_event);
 311        schedule_work(&event_node->work);
 312}
 313
 314static void virtscsi_event_done(struct virtqueue *vq)
 315{
 316        struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 317        struct virtio_scsi *vscsi = shost_priv(sh);
 318        unsigned long flags;
 319
 320        spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
 321        virtscsi_vq_done(vq, virtscsi_complete_event);
 322        spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 323};
 324
 325static void virtscsi_map_sgl(struct scatterlist *sg, unsigned int *p_idx,
 326                             struct scsi_data_buffer *sdb)
 327{
 328        struct sg_table *table = &sdb->table;
 329        struct scatterlist *sg_elem;
 330        unsigned int idx = *p_idx;
 331        int i;
 332
 333        for_each_sg(table->sgl, sg_elem, table->nents, i)
 334                sg[idx++] = *sg_elem;
 335
 336        *p_idx = idx;
 337}
 338
 339/**
 340 * virtscsi_map_cmd - map a scsi_cmd to a virtqueue scatterlist
 341 * @vscsi       : virtio_scsi state
 342 * @cmd         : command structure
 343 * @out_num     : number of read-only elements
 344 * @in_num      : number of write-only elements
 345 * @req_size    : size of the request buffer
 346 * @resp_size   : size of the response buffer
 347 *
 348 * Called with tgt_lock held.
 349 */
 350static void virtscsi_map_cmd(struct virtio_scsi_target_state *tgt,
 351                             struct virtio_scsi_cmd *cmd,
 352                             unsigned *out_num, unsigned *in_num,
 353                             size_t req_size, size_t resp_size)
 354{
 355        struct scsi_cmnd *sc = cmd->sc;
 356        struct scatterlist *sg = tgt->sg;
 357        unsigned int idx = 0;
 358
 359        /* Request header.  */
 360        sg_set_buf(&sg[idx++], &cmd->req, req_size);
 361
 362        /* Data-out buffer.  */
 363        if (sc && sc->sc_data_direction != DMA_FROM_DEVICE)
 364                virtscsi_map_sgl(sg, &idx, scsi_out(sc));
 365
 366        *out_num = idx;
 367
 368        /* Response header.  */
 369        sg_set_buf(&sg[idx++], &cmd->resp, resp_size);
 370
 371        /* Data-in buffer */
 372        if (sc && sc->sc_data_direction != DMA_TO_DEVICE)
 373                virtscsi_map_sgl(sg, &idx, scsi_in(sc));
 374
 375        *in_num = idx - *out_num;
 376}
 377
 378static int virtscsi_kick_cmd(struct virtio_scsi_target_state *tgt,
 379                             struct virtio_scsi_vq *vq,
 380                             struct virtio_scsi_cmd *cmd,
 381                             size_t req_size, size_t resp_size, gfp_t gfp)
 382{
 383        unsigned int out_num, in_num;
 384        unsigned long flags;
 385        int ret;
 386
 387        spin_lock_irqsave(&tgt->tgt_lock, flags);
 388        virtscsi_map_cmd(tgt, cmd, &out_num, &in_num, req_size, resp_size);
 389
 390        spin_lock(&vq->vq_lock);
 391        ret = virtqueue_add_buf(vq->vq, tgt->sg, out_num, in_num, cmd, gfp);
 392        spin_unlock(&tgt->tgt_lock);
 393        if (ret >= 0)
 394                ret = virtqueue_kick_prepare(vq->vq);
 395
 396        spin_unlock_irqrestore(&vq->vq_lock, flags);
 397
 398        if (ret > 0)
 399                virtqueue_notify(vq->vq);
 400        return ret;
 401}
 402
 403static int virtscsi_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
 404{
 405        struct virtio_scsi *vscsi = shost_priv(sh);
 406        struct virtio_scsi_target_state *tgt = vscsi->tgt[sc->device->id];
 407        struct virtio_scsi_cmd *cmd;
 408        int ret;
 409
 410        struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 411        BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
 412
 413        /* TODO: check feature bit and fail if unsupported?  */
 414        BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
 415
 416        dev_dbg(&sc->device->sdev_gendev,
 417                "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
 418
 419        ret = SCSI_MLQUEUE_HOST_BUSY;
 420        cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC);
 421        if (!cmd)
 422                goto out;
 423
 424        memset(cmd, 0, sizeof(*cmd));
 425        cmd->sc = sc;
 426        cmd->req.cmd = (struct virtio_scsi_cmd_req){
 427                .lun[0] = 1,
 428                .lun[1] = sc->device->id,
 429                .lun[2] = (sc->device->lun >> 8) | 0x40,
 430                .lun[3] = sc->device->lun & 0xff,
 431                .tag = (unsigned long)sc,
 432                .task_attr = VIRTIO_SCSI_S_SIMPLE,
 433                .prio = 0,
 434                .crn = 0,
 435        };
 436
 437        BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
 438        memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
 439
 440        if (virtscsi_kick_cmd(tgt, &vscsi->req_vq, cmd,
 441                              sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
 442                              GFP_ATOMIC) >= 0)
 443                ret = 0;
 444
 445out:
 446        return ret;
 447}
 448
 449static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 450{
 451        DECLARE_COMPLETION_ONSTACK(comp);
 452        struct virtio_scsi_target_state *tgt = vscsi->tgt[cmd->sc->device->id];
 453        int ret = FAILED;
 454
 455        cmd->comp = &comp;
 456        if (virtscsi_kick_cmd(tgt, &vscsi->ctrl_vq, cmd,
 457                              sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
 458                              GFP_NOIO) < 0)
 459                goto out;
 460
 461        wait_for_completion(&comp);
 462        if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
 463            cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
 464                ret = SUCCESS;
 465
 466out:
 467        mempool_free(cmd, virtscsi_cmd_pool);
 468        return ret;
 469}
 470
 471static int virtscsi_device_reset(struct scsi_cmnd *sc)
 472{
 473        struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 474        struct virtio_scsi_cmd *cmd;
 475
 476        sdev_printk(KERN_INFO, sc->device, "device reset\n");
 477        cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 478        if (!cmd)
 479                return FAILED;
 480
 481        memset(cmd, 0, sizeof(*cmd));
 482        cmd->sc = sc;
 483        cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 484                .type = VIRTIO_SCSI_T_TMF,
 485                .subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET,
 486                .lun[0] = 1,
 487                .lun[1] = sc->device->id,
 488                .lun[2] = (sc->device->lun >> 8) | 0x40,
 489                .lun[3] = sc->device->lun & 0xff,
 490        };
 491        return virtscsi_tmf(vscsi, cmd);
 492}
 493
 494static int virtscsi_abort(struct scsi_cmnd *sc)
 495{
 496        struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 497        struct virtio_scsi_cmd *cmd;
 498
 499        scmd_printk(KERN_INFO, sc, "abort\n");
 500        cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 501        if (!cmd)
 502                return FAILED;
 503
 504        memset(cmd, 0, sizeof(*cmd));
 505        cmd->sc = sc;
 506        cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 507                .type = VIRTIO_SCSI_T_TMF,
 508                .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
 509                .lun[0] = 1,
 510                .lun[1] = sc->device->id,
 511                .lun[2] = (sc->device->lun >> 8) | 0x40,
 512                .lun[3] = sc->device->lun & 0xff,
 513                .tag = (unsigned long)sc,
 514        };
 515        return virtscsi_tmf(vscsi, cmd);
 516}
 517
 518static struct scsi_host_template virtscsi_host_template = {
 519        .module = THIS_MODULE,
 520        .name = "Virtio SCSI HBA",
 521        .proc_name = "virtio_scsi",
 522        .queuecommand = virtscsi_queuecommand,
 523        .this_id = -1,
 524        .eh_abort_handler = virtscsi_abort,
 525        .eh_device_reset_handler = virtscsi_device_reset,
 526
 527        .can_queue = 1024,
 528        .dma_boundary = UINT_MAX,
 529        .use_clustering = ENABLE_CLUSTERING,
 530};
 531
 532#define virtscsi_config_get(vdev, fld) \
 533        ({ \
 534                typeof(((struct virtio_scsi_config *)0)->fld) __val; \
 535                vdev->config->get(vdev, \
 536                                  offsetof(struct virtio_scsi_config, fld), \
 537                                  &__val, sizeof(__val)); \
 538                __val; \
 539        })
 540
 541#define virtscsi_config_set(vdev, fld, val) \
 542        (void)({ \
 543                typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
 544                vdev->config->set(vdev, \
 545                                  offsetof(struct virtio_scsi_config, fld), \
 546                                  &__val, sizeof(__val)); \
 547        })
 548
 549static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
 550                             struct virtqueue *vq)
 551{
 552        spin_lock_init(&virtscsi_vq->vq_lock);
 553        virtscsi_vq->vq = vq;
 554}
 555
 556static struct virtio_scsi_target_state *virtscsi_alloc_tgt(
 557        struct virtio_device *vdev, int sg_elems)
 558{
 559        struct virtio_scsi_target_state *tgt;
 560        gfp_t gfp_mask = GFP_KERNEL;
 561
 562        /* We need extra sg elements at head and tail.  */
 563        tgt = kmalloc(sizeof(*tgt) + sizeof(tgt->sg[0]) * (sg_elems + 2),
 564                      gfp_mask);
 565
 566        if (!tgt)
 567                return NULL;
 568
 569        spin_lock_init(&tgt->tgt_lock);
 570        sg_init_table(tgt->sg, sg_elems + 2);
 571        return tgt;
 572}
 573
 574static void virtscsi_scan(struct virtio_device *vdev)
 575{
 576        struct Scsi_Host *shost = (struct Scsi_Host *)vdev->priv;
 577
 578        scsi_scan_host(shost);
 579}
 580
 581static void virtscsi_remove_vqs(struct virtio_device *vdev)
 582{
 583        struct Scsi_Host *sh = virtio_scsi_host(vdev);
 584        struct virtio_scsi *vscsi = shost_priv(sh);
 585        u32 i, num_targets;
 586
 587        /* Stop all the virtqueues. */
 588        vdev->config->reset(vdev);
 589
 590        num_targets = sh->max_id;
 591        for (i = 0; i < num_targets; i++) {
 592                kfree(vscsi->tgt[i]);
 593                vscsi->tgt[i] = NULL;
 594        }
 595
 596        vdev->config->del_vqs(vdev);
 597}
 598
 599static int virtscsi_init(struct virtio_device *vdev,
 600                         struct virtio_scsi *vscsi, int num_targets)
 601{
 602        int err;
 603        struct virtqueue *vqs[3];
 604        u32 i, sg_elems;
 605
 606        vq_callback_t *callbacks[] = {
 607                virtscsi_ctrl_done,
 608                virtscsi_event_done,
 609                virtscsi_req_done
 610        };
 611        const char *names[] = {
 612                "control",
 613                "event",
 614                "request"
 615        };
 616
 617        /* Discover virtqueues and write information to configuration.  */
 618        err = vdev->config->find_vqs(vdev, 3, vqs, callbacks, names);
 619        if (err)
 620                return err;
 621
 622        virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
 623        virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
 624        virtscsi_init_vq(&vscsi->req_vq, vqs[2]);
 625
 626        virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 627        virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 628
 629        if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 630                virtscsi_kick_event_all(vscsi);
 631
 632        /* We need to know how many segments before we allocate.  */
 633        sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 634
 635        for (i = 0; i < num_targets; i++) {
 636                vscsi->tgt[i] = virtscsi_alloc_tgt(vdev, sg_elems);
 637                if (!vscsi->tgt[i]) {
 638                        err = -ENOMEM;
 639                        goto out;
 640                }
 641        }
 642        err = 0;
 643
 644out:
 645        if (err)
 646                virtscsi_remove_vqs(vdev);
 647        return err;
 648}
 649
 650static int __devinit virtscsi_probe(struct virtio_device *vdev)
 651{
 652        struct Scsi_Host *shost;
 653        struct virtio_scsi *vscsi;
 654        int err;
 655        u32 sg_elems, num_targets;
 656        u32 cmd_per_lun;
 657
 658        /* Allocate memory and link the structs together.  */
 659        num_targets = virtscsi_config_get(vdev, max_target) + 1;
 660        shost = scsi_host_alloc(&virtscsi_host_template,
 661                sizeof(*vscsi)
 662                + num_targets * sizeof(struct virtio_scsi_target_state));
 663
 664        if (!shost)
 665                return -ENOMEM;
 666
 667        sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 668        shost->sg_tablesize = sg_elems;
 669        vscsi = shost_priv(shost);
 670        vscsi->vdev = vdev;
 671        vdev->priv = shost;
 672
 673        err = virtscsi_init(vdev, vscsi, num_targets);
 674        if (err)
 675                goto virtscsi_init_failed;
 676
 677        cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
 678        shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
 679        shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
 680        shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1;
 681        shost->max_id = num_targets;
 682        shost->max_channel = 0;
 683        shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
 684        err = scsi_add_host(shost, &vdev->dev);
 685        if (err)
 686                goto scsi_add_host_failed;
 687        /*
 688         * scsi_scan_host() happens in virtscsi_scan() via virtio_driver->scan()
 689         * after VIRTIO_CONFIG_S_DRIVER_OK has been set..
 690         */
 691        return 0;
 692
 693scsi_add_host_failed:
 694        vdev->config->del_vqs(vdev);
 695virtscsi_init_failed:
 696        scsi_host_put(shost);
 697        return err;
 698}
 699
 700static void __devexit virtscsi_remove(struct virtio_device *vdev)
 701{
 702        struct Scsi_Host *shost = virtio_scsi_host(vdev);
 703        struct virtio_scsi *vscsi = shost_priv(shost);
 704
 705        if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 706                virtscsi_cancel_event_work(vscsi);
 707
 708        scsi_remove_host(shost);
 709
 710        virtscsi_remove_vqs(vdev);
 711        scsi_host_put(shost);
 712}
 713
 714#ifdef CONFIG_PM
 715static int virtscsi_freeze(struct virtio_device *vdev)
 716{
 717        virtscsi_remove_vqs(vdev);
 718        return 0;
 719}
 720
 721static int virtscsi_restore(struct virtio_device *vdev)
 722{
 723        struct Scsi_Host *sh = virtio_scsi_host(vdev);
 724        struct virtio_scsi *vscsi = shost_priv(sh);
 725
 726        return virtscsi_init(vdev, vscsi, sh->max_id);
 727}
 728#endif
 729
 730static struct virtio_device_id id_table[] = {
 731        { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
 732        { 0 },
 733};
 734
 735static unsigned int features[] = {
 736        VIRTIO_SCSI_F_HOTPLUG
 737};
 738
 739static struct virtio_driver virtio_scsi_driver = {
 740        .feature_table = features,
 741        .feature_table_size = ARRAY_SIZE(features),
 742        .driver.name = KBUILD_MODNAME,
 743        .driver.owner = THIS_MODULE,
 744        .id_table = id_table,
 745        .probe = virtscsi_probe,
 746        .scan = virtscsi_scan,
 747#ifdef CONFIG_PM
 748        .freeze = virtscsi_freeze,
 749        .restore = virtscsi_restore,
 750#endif
 751        .remove = __devexit_p(virtscsi_remove),
 752};
 753
 754static int __init init(void)
 755{
 756        int ret = -ENOMEM;
 757
 758        virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
 759        if (!virtscsi_cmd_cache) {
 760                printk(KERN_ERR "kmem_cache_create() for "
 761                                "virtscsi_cmd_cache failed\n");
 762                goto error;
 763        }
 764
 765
 766        virtscsi_cmd_pool =
 767                mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
 768                                         virtscsi_cmd_cache);
 769        if (!virtscsi_cmd_pool) {
 770                printk(KERN_ERR "mempool_create() for"
 771                                "virtscsi_cmd_pool failed\n");
 772                goto error;
 773        }
 774        ret = register_virtio_driver(&virtio_scsi_driver);
 775        if (ret < 0)
 776                goto error;
 777
 778        return 0;
 779
 780error:
 781        if (virtscsi_cmd_pool) {
 782                mempool_destroy(virtscsi_cmd_pool);
 783                virtscsi_cmd_pool = NULL;
 784        }
 785        if (virtscsi_cmd_cache) {
 786                kmem_cache_destroy(virtscsi_cmd_cache);
 787                virtscsi_cmd_cache = NULL;
 788        }
 789        return ret;
 790}
 791
 792static void __exit fini(void)
 793{
 794        unregister_virtio_driver(&virtio_scsi_driver);
 795        mempool_destroy(virtscsi_cmd_pool);
 796        kmem_cache_destroy(virtscsi_cmd_cache);
 797}
 798module_init(init);
 799module_exit(fini);
 800
 801MODULE_DEVICE_TABLE(virtio, id_table);
 802MODULE_DESCRIPTION("Virtio SCSI HBA driver");
 803MODULE_LICENSE("GPL");
 804
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