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 err;
 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        err = virtqueue_add_buf(vscsi->event_vq.vq, &sg, 0, 1, event_node,
 227                                GFP_ATOMIC);
 228        if (!err)
 229                virtqueue_kick(vscsi->event_vq.vq);
 230
 231        spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 232
 233        return err;
 234}
 235
 236static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
 237{
 238        int i;
 239
 240        for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
 241                vscsi->event_list[i].vscsi = vscsi;
 242                virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
 243        }
 244
 245        return 0;
 246}
 247
 248static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
 249{
 250        int i;
 251
 252        for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
 253                cancel_work_sync(&vscsi->event_list[i].work);
 254}
 255
 256static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
 257                                                struct virtio_scsi_event *event)
 258{
 259        struct scsi_device *sdev;
 260        struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 261        unsigned int target = event->lun[1];
 262        unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 263
 264        switch (event->reason) {
 265        case VIRTIO_SCSI_EVT_RESET_RESCAN:
 266                scsi_add_device(shost, 0, target, lun);
 267                break;
 268        case VIRTIO_SCSI_EVT_RESET_REMOVED:
 269                sdev = scsi_device_lookup(shost, 0, target, lun);
 270                if (sdev) {
 271                        scsi_remove_device(sdev);
 272                        scsi_device_put(sdev);
 273                } else {
 274                        pr_err("SCSI device %d 0 %d %d not found\n",
 275                                shost->host_no, target, lun);
 276                }
 277                break;
 278        default:
 279                pr_info("Unsupport virtio scsi event reason %x\n", event->reason);
 280        }
 281}
 282
 283static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
 284                                         struct virtio_scsi_event *event)
 285{
 286        struct scsi_device *sdev;
 287        struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 288        unsigned int target = event->lun[1];
 289        unsigned int lun = (event->lun[2] << 8) | event->lun[3];
 290        u8 asc = event->reason & 255;
 291        u8 ascq = event->reason >> 8;
 292
 293        sdev = scsi_device_lookup(shost, 0, target, lun);
 294        if (!sdev) {
 295                pr_err("SCSI device %d 0 %d %d not found\n",
 296                        shost->host_no, target, lun);
 297                return;
 298        }
 299
 300        /* Handle "Parameters changed", "Mode parameters changed", and
 301           "Capacity data has changed".  */
 302        if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
 303                scsi_rescan_device(&sdev->sdev_gendev);
 304
 305        scsi_device_put(sdev);
 306}
 307
 308static void virtscsi_handle_event(struct work_struct *work)
 309{
 310        struct virtio_scsi_event_node *event_node =
 311                container_of(work, struct virtio_scsi_event_node, work);
 312        struct virtio_scsi *vscsi = event_node->vscsi;
 313        struct virtio_scsi_event *event = &event_node->event;
 314
 315        if (event->event & VIRTIO_SCSI_T_EVENTS_MISSED) {
 316                event->event &= ~VIRTIO_SCSI_T_EVENTS_MISSED;
 317                scsi_scan_host(virtio_scsi_host(vscsi->vdev));
 318        }
 319
 320        switch (event->event) {
 321        case VIRTIO_SCSI_T_NO_EVENT:
 322                break;
 323        case VIRTIO_SCSI_T_TRANSPORT_RESET:
 324                virtscsi_handle_transport_reset(vscsi, event);
 325                break;
 326        case VIRTIO_SCSI_T_PARAM_CHANGE:
 327                virtscsi_handle_param_change(vscsi, event);
 328                break;
 329        default:
 330                pr_err("Unsupport virtio scsi event %x\n", event->event);
 331        }
 332        virtscsi_kick_event(vscsi, event_node);
 333}
 334
 335static void virtscsi_complete_event(void *buf)
 336{
 337        struct virtio_scsi_event_node *event_node = buf;
 338
 339        INIT_WORK(&event_node->work, virtscsi_handle_event);
 340        schedule_work(&event_node->work);
 341}
 342
 343static void virtscsi_event_done(struct virtqueue *vq)
 344{
 345        struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
 346        struct virtio_scsi *vscsi = shost_priv(sh);
 347        unsigned long flags;
 348
 349        spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
 350        virtscsi_vq_done(vq, virtscsi_complete_event);
 351        spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
 352};
 353
 354static void virtscsi_map_sgl(struct scatterlist *sg, unsigned int *p_idx,
 355                             struct scsi_data_buffer *sdb)
 356{
 357        struct sg_table *table = &sdb->table;
 358        struct scatterlist *sg_elem;
 359        unsigned int idx = *p_idx;
 360        int i;
 361
 362        for_each_sg(table->sgl, sg_elem, table->nents, i)
 363                sg[idx++] = *sg_elem;
 364
 365        *p_idx = idx;
 366}
 367
 368/**
 369 * virtscsi_map_cmd - map a scsi_cmd to a virtqueue scatterlist
 370 * @vscsi       : virtio_scsi state
 371 * @cmd         : command structure
 372 * @out_num     : number of read-only elements
 373 * @in_num      : number of write-only elements
 374 * @req_size    : size of the request buffer
 375 * @resp_size   : size of the response buffer
 376 *
 377 * Called with tgt_lock held.
 378 */
 379static void virtscsi_map_cmd(struct virtio_scsi_target_state *tgt,
 380                             struct virtio_scsi_cmd *cmd,
 381                             unsigned *out_num, unsigned *in_num,
 382                             size_t req_size, size_t resp_size)
 383{
 384        struct scsi_cmnd *sc = cmd->sc;
 385        struct scatterlist *sg = tgt->sg;
 386        unsigned int idx = 0;
 387
 388        /* Request header.  */
 389        sg_set_buf(&sg[idx++], &cmd->req, req_size);
 390
 391        /* Data-out buffer.  */
 392        if (sc && sc->sc_data_direction != DMA_FROM_DEVICE)
 393                virtscsi_map_sgl(sg, &idx, scsi_out(sc));
 394
 395        *out_num = idx;
 396
 397        /* Response header.  */
 398        sg_set_buf(&sg[idx++], &cmd->resp, resp_size);
 399
 400        /* Data-in buffer */
 401        if (sc && sc->sc_data_direction != DMA_TO_DEVICE)
 402                virtscsi_map_sgl(sg, &idx, scsi_in(sc));
 403
 404        *in_num = idx - *out_num;
 405}
 406
 407static int virtscsi_kick_cmd(struct virtio_scsi_target_state *tgt,
 408                             struct virtio_scsi_vq *vq,
 409                             struct virtio_scsi_cmd *cmd,
 410                             size_t req_size, size_t resp_size, gfp_t gfp)
 411{
 412        unsigned int out_num, in_num;
 413        unsigned long flags;
 414        int err;
 415        bool needs_kick = false;
 416
 417        spin_lock_irqsave(&tgt->tgt_lock, flags);
 418        virtscsi_map_cmd(tgt, cmd, &out_num, &in_num, req_size, resp_size);
 419
 420        spin_lock(&vq->vq_lock);
 421        err = virtqueue_add_buf(vq->vq, tgt->sg, out_num, in_num, cmd, gfp);
 422        spin_unlock(&tgt->tgt_lock);
 423        if (!err)
 424                needs_kick = virtqueue_kick_prepare(vq->vq);
 425
 426        spin_unlock_irqrestore(&vq->vq_lock, flags);
 427
 428        if (needs_kick)
 429                virtqueue_notify(vq->vq);
 430        return err;
 431}
 432
 433static int virtscsi_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
 434{
 435        struct virtio_scsi *vscsi = shost_priv(sh);
 436        struct virtio_scsi_target_state *tgt = vscsi->tgt[sc->device->id];
 437        struct virtio_scsi_cmd *cmd;
 438        int ret;
 439
 440        struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
 441        BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
 442
 443        /* TODO: check feature bit and fail if unsupported?  */
 444        BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
 445
 446        dev_dbg(&sc->device->sdev_gendev,
 447                "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
 448
 449        ret = SCSI_MLQUEUE_HOST_BUSY;
 450        cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC);
 451        if (!cmd)
 452                goto out;
 453
 454        memset(cmd, 0, sizeof(*cmd));
 455        cmd->sc = sc;
 456        cmd->req.cmd = (struct virtio_scsi_cmd_req){
 457                .lun[0] = 1,
 458                .lun[1] = sc->device->id,
 459                .lun[2] = (sc->device->lun >> 8) | 0x40,
 460                .lun[3] = sc->device->lun & 0xff,
 461                .tag = (unsigned long)sc,
 462                .task_attr = VIRTIO_SCSI_S_SIMPLE,
 463                .prio = 0,
 464                .crn = 0,
 465        };
 466
 467        BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
 468        memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
 469
 470        if (virtscsi_kick_cmd(tgt, &vscsi->req_vq, cmd,
 471                              sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
 472                              GFP_ATOMIC) == 0)
 473                ret = 0;
 474        else
 475                mempool_free(cmd, virtscsi_cmd_pool);
 476
 477out:
 478        return ret;
 479}
 480
 481static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
 482{
 483        DECLARE_COMPLETION_ONSTACK(comp);
 484        struct virtio_scsi_target_state *tgt = vscsi->tgt[cmd->sc->device->id];
 485        int ret = FAILED;
 486
 487        cmd->comp = &comp;
 488        if (virtscsi_kick_cmd(tgt, &vscsi->ctrl_vq, cmd,
 489                              sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
 490                              GFP_NOIO) < 0)
 491                goto out;
 492
 493        wait_for_completion(&comp);
 494        if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
 495            cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
 496                ret = SUCCESS;
 497
 498out:
 499        mempool_free(cmd, virtscsi_cmd_pool);
 500        return ret;
 501}
 502
 503static int virtscsi_device_reset(struct scsi_cmnd *sc)
 504{
 505        struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 506        struct virtio_scsi_cmd *cmd;
 507
 508        sdev_printk(KERN_INFO, sc->device, "device reset\n");
 509        cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 510        if (!cmd)
 511                return FAILED;
 512
 513        memset(cmd, 0, sizeof(*cmd));
 514        cmd->sc = sc;
 515        cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 516                .type = VIRTIO_SCSI_T_TMF,
 517                .subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET,
 518                .lun[0] = 1,
 519                .lun[1] = sc->device->id,
 520                .lun[2] = (sc->device->lun >> 8) | 0x40,
 521                .lun[3] = sc->device->lun & 0xff,
 522        };
 523        return virtscsi_tmf(vscsi, cmd);
 524}
 525
 526static int virtscsi_abort(struct scsi_cmnd *sc)
 527{
 528        struct virtio_scsi *vscsi = shost_priv(sc->device->host);
 529        struct virtio_scsi_cmd *cmd;
 530
 531        scmd_printk(KERN_INFO, sc, "abort\n");
 532        cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
 533        if (!cmd)
 534                return FAILED;
 535
 536        memset(cmd, 0, sizeof(*cmd));
 537        cmd->sc = sc;
 538        cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
 539                .type = VIRTIO_SCSI_T_TMF,
 540                .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
 541                .lun[0] = 1,
 542                .lun[1] = sc->device->id,
 543                .lun[2] = (sc->device->lun >> 8) | 0x40,
 544                .lun[3] = sc->device->lun & 0xff,
 545                .tag = (unsigned long)sc,
 546        };
 547        return virtscsi_tmf(vscsi, cmd);
 548}
 549
 550static struct scsi_host_template virtscsi_host_template = {
 551        .module = THIS_MODULE,
 552        .name = "Virtio SCSI HBA",
 553        .proc_name = "virtio_scsi",
 554        .queuecommand = virtscsi_queuecommand,
 555        .this_id = -1,
 556        .eh_abort_handler = virtscsi_abort,
 557        .eh_device_reset_handler = virtscsi_device_reset,
 558
 559        .can_queue = 1024,
 560        .dma_boundary = UINT_MAX,
 561        .use_clustering = ENABLE_CLUSTERING,
 562};
 563
 564#define virtscsi_config_get(vdev, fld) \
 565        ({ \
 566                typeof(((struct virtio_scsi_config *)0)->fld) __val; \
 567                vdev->config->get(vdev, \
 568                                  offsetof(struct virtio_scsi_config, fld), \
 569                                  &__val, sizeof(__val)); \
 570                __val; \
 571        })
 572
 573#define virtscsi_config_set(vdev, fld, val) \
 574        (void)({ \
 575                typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
 576                vdev->config->set(vdev, \
 577                                  offsetof(struct virtio_scsi_config, fld), \
 578                                  &__val, sizeof(__val)); \
 579        })
 580
 581static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
 582                             struct virtqueue *vq)
 583{
 584        spin_lock_init(&virtscsi_vq->vq_lock);
 585        virtscsi_vq->vq = vq;
 586}
 587
 588static struct virtio_scsi_target_state *virtscsi_alloc_tgt(
 589        struct virtio_device *vdev, int sg_elems)
 590{
 591        struct virtio_scsi_target_state *tgt;
 592        gfp_t gfp_mask = GFP_KERNEL;
 593
 594        /* We need extra sg elements at head and tail.  */
 595        tgt = kmalloc(sizeof(*tgt) + sizeof(tgt->sg[0]) * (sg_elems + 2),
 596                      gfp_mask);
 597
 598        if (!tgt)
 599                return NULL;
 600
 601        spin_lock_init(&tgt->tgt_lock);
 602        sg_init_table(tgt->sg, sg_elems + 2);
 603        return tgt;
 604}
 605
 606static void virtscsi_scan(struct virtio_device *vdev)
 607{
 608        struct Scsi_Host *shost = (struct Scsi_Host *)vdev->priv;
 609
 610        scsi_scan_host(shost);
 611}
 612
 613static void virtscsi_remove_vqs(struct virtio_device *vdev)
 614{
 615        struct Scsi_Host *sh = virtio_scsi_host(vdev);
 616        struct virtio_scsi *vscsi = shost_priv(sh);
 617        u32 i, num_targets;
 618
 619        /* Stop all the virtqueues. */
 620        vdev->config->reset(vdev);
 621
 622        num_targets = sh->max_id;
 623        for (i = 0; i < num_targets; i++) {
 624                kfree(vscsi->tgt[i]);
 625                vscsi->tgt[i] = NULL;
 626        }
 627
 628        vdev->config->del_vqs(vdev);
 629}
 630
 631static int virtscsi_init(struct virtio_device *vdev,
 632                         struct virtio_scsi *vscsi, int num_targets)
 633{
 634        int err;
 635        struct virtqueue *vqs[3];
 636        u32 i, sg_elems;
 637
 638        vq_callback_t *callbacks[] = {
 639                virtscsi_ctrl_done,
 640                virtscsi_event_done,
 641                virtscsi_req_done
 642        };
 643        const char *names[] = {
 644                "control",
 645                "event",
 646                "request"
 647        };
 648
 649        /* Discover virtqueues and write information to configuration.  */
 650        err = vdev->config->find_vqs(vdev, 3, vqs, callbacks, names);
 651        if (err)
 652                return err;
 653
 654        virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
 655        virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
 656        virtscsi_init_vq(&vscsi->req_vq, vqs[2]);
 657
 658        virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 659        virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 660
 661        if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 662                virtscsi_kick_event_all(vscsi);
 663
 664        /* We need to know how many segments before we allocate.  */
 665        sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 666
 667        for (i = 0; i < num_targets; i++) {
 668                vscsi->tgt[i] = virtscsi_alloc_tgt(vdev, sg_elems);
 669                if (!vscsi->tgt[i]) {
 670                        err = -ENOMEM;
 671                        goto out;
 672                }
 673        }
 674        err = 0;
 675
 676out:
 677        if (err)
 678                virtscsi_remove_vqs(vdev);
 679        return err;
 680}
 681
 682static int virtscsi_probe(struct virtio_device *vdev)
 683{
 684        struct Scsi_Host *shost;
 685        struct virtio_scsi *vscsi;
 686        int err;
 687        u32 sg_elems, num_targets;
 688        u32 cmd_per_lun;
 689
 690        /* Allocate memory and link the structs together.  */
 691        num_targets = virtscsi_config_get(vdev, max_target) + 1;
 692        shost = scsi_host_alloc(&virtscsi_host_template,
 693                sizeof(*vscsi)
 694                + num_targets * sizeof(struct virtio_scsi_target_state));
 695
 696        if (!shost)
 697                return -ENOMEM;
 698
 699        sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
 700        shost->sg_tablesize = sg_elems;
 701        vscsi = shost_priv(shost);
 702        vscsi->vdev = vdev;
 703        vdev->priv = shost;
 704
 705        err = virtscsi_init(vdev, vscsi, num_targets);
 706        if (err)
 707                goto virtscsi_init_failed;
 708
 709        cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
 710        shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
 711        shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
 712
 713        /* LUNs > 256 are reported with format 1, so they go in the range
 714         * 16640-32767.
 715         */
 716        shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
 717        shost->max_id = num_targets;
 718        shost->max_channel = 0;
 719        shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
 720        err = scsi_add_host(shost, &vdev->dev);
 721        if (err)
 722                goto scsi_add_host_failed;
 723        /*
 724         * scsi_scan_host() happens in virtscsi_scan() via virtio_driver->scan()
 725         * after VIRTIO_CONFIG_S_DRIVER_OK has been set..
 726         */
 727        return 0;
 728
 729scsi_add_host_failed:
 730        vdev->config->del_vqs(vdev);
 731virtscsi_init_failed:
 732        scsi_host_put(shost);
 733        return err;
 734}
 735
 736static void virtscsi_remove(struct virtio_device *vdev)
 737{
 738        struct Scsi_Host *shost = virtio_scsi_host(vdev);
 739        struct virtio_scsi *vscsi = shost_priv(shost);
 740
 741        if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
 742                virtscsi_cancel_event_work(vscsi);
 743
 744        scsi_remove_host(shost);
 745
 746        virtscsi_remove_vqs(vdev);
 747        scsi_host_put(shost);
 748}
 749
 750#ifdef CONFIG_PM
 751static int virtscsi_freeze(struct virtio_device *vdev)
 752{
 753        virtscsi_remove_vqs(vdev);
 754        return 0;
 755}
 756
 757static int virtscsi_restore(struct virtio_device *vdev)
 758{
 759        struct Scsi_Host *sh = virtio_scsi_host(vdev);
 760        struct virtio_scsi *vscsi = shost_priv(sh);
 761
 762        return virtscsi_init(vdev, vscsi, sh->max_id);
 763}
 764#endif
 765
 766static struct virtio_device_id id_table[] = {
 767        { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
 768        { 0 },
 769};
 770
 771static unsigned int features[] = {
 772        VIRTIO_SCSI_F_HOTPLUG,
 773        VIRTIO_SCSI_F_CHANGE,
 774};
 775
 776static struct virtio_driver virtio_scsi_driver = {
 777        .feature_table = features,
 778        .feature_table_size = ARRAY_SIZE(features),
 779        .driver.name = KBUILD_MODNAME,
 780        .driver.owner = THIS_MODULE,
 781        .id_table = id_table,
 782        .probe = virtscsi_probe,
 783        .scan = virtscsi_scan,
 784#ifdef CONFIG_PM
 785        .freeze = virtscsi_freeze,
 786        .restore = virtscsi_restore,
 787#endif
 788        .remove = virtscsi_remove,
 789};
 790
 791static int __init init(void)
 792{
 793        int ret = -ENOMEM;
 794
 795        virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
 796        if (!virtscsi_cmd_cache) {
 797                printk(KERN_ERR "kmem_cache_create() for "
 798                                "virtscsi_cmd_cache failed\n");
 799                goto error;
 800        }
 801
 802
 803        virtscsi_cmd_pool =
 804                mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
 805                                         virtscsi_cmd_cache);
 806        if (!virtscsi_cmd_pool) {
 807                printk(KERN_ERR "mempool_create() for"
 808                                "virtscsi_cmd_pool failed\n");
 809                goto error;
 810        }
 811        ret = register_virtio_driver(&virtio_scsi_driver);
 812        if (ret < 0)
 813                goto error;
 814
 815        return 0;
 816
 817error:
 818        if (virtscsi_cmd_pool) {
 819                mempool_destroy(virtscsi_cmd_pool);
 820                virtscsi_cmd_pool = NULL;
 821        }
 822        if (virtscsi_cmd_cache) {
 823                kmem_cache_destroy(virtscsi_cmd_cache);
 824                virtscsi_cmd_cache = NULL;
 825        }
 826        return ret;
 827}
 828
 829static void __exit fini(void)
 830{
 831        unregister_virtio_driver(&virtio_scsi_driver);
 832        mempool_destroy(virtscsi_cmd_pool);
 833        kmem_cache_destroy(virtscsi_cmd_cache);
 834}
 835module_init(init);
 836module_exit(fini);
 837
 838MODULE_DEVICE_TABLE(virtio, id_table);
 839MODULE_DESCRIPTION("Virtio SCSI HBA driver");
 840MODULE_LICENSE("GPL");
 841
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