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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 17 18 #include <linux/module.h> 19 #include <linux/slab.h> 20 #include <linux/mempool.h> 21 #include <linux/virtio.h> 22 #include <linux/virtio_ids.h> 23 #include <linux/virtio_config.h> 24 #include <linux/virtio_scsi.h> 25 #include <linux/cpu.h> 26 #include <scsi/scsi_host.h> 27 #include <scsi/scsi_device.h> 28 #include <scsi/scsi_cmnd.h> 29 30 #define VIRTIO_SCSI_MEMPOOL_SZ 64 31 #define VIRTIO_SCSI_EVENT_LEN 8 32 #define VIRTIO_SCSI_VQ_BASE 2 33 34 /* Command queue element */ 35 struct virtio_scsi_cmd { 36 struct scsi_cmnd *sc; 37 struct completion *comp; 38 union { 39 struct virtio_scsi_cmd_req cmd; 40 struct virtio_scsi_ctrl_tmf_req tmf; 41 struct virtio_scsi_ctrl_an_req an; 42 } req; 43 union { 44 struct virtio_scsi_cmd_resp cmd; 45 struct virtio_scsi_ctrl_tmf_resp tmf; 46 struct virtio_scsi_ctrl_an_resp an; 47 struct virtio_scsi_event evt; 48 } resp; 49 } ____cacheline_aligned_in_smp; 50 51 struct virtio_scsi_event_node { 52 struct virtio_scsi *vscsi; 53 struct virtio_scsi_event event; 54 struct work_struct work; 55 }; 56 57 struct virtio_scsi_vq { 58 /* Protects vq */ 59 spinlock_t vq_lock; 60 61 struct virtqueue *vq; 62 }; 63 64 /* 65 * Per-target queue state. 66 * 67 * This struct holds the data needed by the queue steering policy. When a 68 * target is sent multiple requests, we need to drive them to the same queue so 69 * that FIFO processing order is kept. However, if a target was idle, we can 70 * choose a queue arbitrarily. In this case the queue is chosen according to 71 * the current VCPU, so the driver expects the number of request queues to be 72 * equal to the number of VCPUs. This makes it easy and fast to select the 73 * queue, and also lets the driver optimize the IRQ affinity for the virtqueues 74 * (each virtqueue's affinity is set to the CPU that "owns" the queue). 75 * 76 * An interesting effect of this policy is that only writes to req_vq need to 77 * take the tgt_lock. Read can be done outside the lock because: 78 * 79 * - writes of req_vq only occur when atomic_inc_return(&tgt->reqs) returns 1. 80 * In that case, no other CPU is reading req_vq: even if they were in 81 * virtscsi_queuecommand_multi, they would be spinning on tgt_lock. 82 * 83 * - reads of req_vq only occur when the target is not idle (reqs != 0). 84 * A CPU that enters virtscsi_queuecommand_multi will not modify req_vq. 85 * 86 * Similarly, decrements of reqs are never concurrent with writes of req_vq. 87 * Thus they can happen outside the tgt_lock, provided of course we make reqs 88 * an atomic_t. 89 */ 90 struct virtio_scsi_target_state { 91 /* This spinlock never held at the same time as vq_lock. */ 92 spinlock_t tgt_lock; 93 94 /* Count of outstanding requests. */ 95 atomic_t reqs; 96 97 /* Currently active virtqueue for requests sent to this target. */ 98 struct virtio_scsi_vq *req_vq; 99 }; 100 101 /* Driver instance state */ 102 struct virtio_scsi { 103 struct virtio_device *vdev; 104 105 /* Get some buffers ready for event vq */ 106 struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN]; 107 108 u32 num_queues; 109 110 /* If the affinity hint is set for virtqueues */ 111 bool affinity_hint_set; 112 113 /* CPU hotplug notifier */ 114 struct notifier_block nb; 115 116 struct virtio_scsi_vq ctrl_vq; 117 struct virtio_scsi_vq event_vq; 118 struct virtio_scsi_vq req_vqs[]; 119 }; 120 121 static struct kmem_cache *virtscsi_cmd_cache; 122 static mempool_t *virtscsi_cmd_pool; 123 124 static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev) 125 { 126 return vdev->priv; 127 } 128 129 static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid) 130 { 131 if (!resid) 132 return; 133 134 if (!scsi_bidi_cmnd(sc)) { 135 scsi_set_resid(sc, resid); 136 return; 137 } 138 139 scsi_in(sc)->resid = min(resid, scsi_in(sc)->length); 140 scsi_out(sc)->resid = resid - scsi_in(sc)->resid; 141 } 142 143 /** 144 * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done 145 * 146 * Called with vq_lock held. 147 */ 148 static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf) 149 { 150 struct virtio_scsi_cmd *cmd = buf; 151 struct scsi_cmnd *sc = cmd->sc; 152 struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd; 153 struct virtio_scsi_target_state *tgt = 154 scsi_target(sc->device)->hostdata; 155 156 dev_dbg(&sc->device->sdev_gendev, 157 "cmd %p response %u status %#02x sense_len %u\n", 158 sc, resp->response, resp->status, resp->sense_len); 159 160 sc->result = resp->status; 161 virtscsi_compute_resid(sc, resp->resid); 162 switch (resp->response) { 163 case VIRTIO_SCSI_S_OK: 164 set_host_byte(sc, DID_OK); 165 break; 166 case VIRTIO_SCSI_S_OVERRUN: 167 set_host_byte(sc, DID_ERROR); 168 break; 169 case VIRTIO_SCSI_S_ABORTED: 170 set_host_byte(sc, DID_ABORT); 171 break; 172 case VIRTIO_SCSI_S_BAD_TARGET: 173 set_host_byte(sc, DID_BAD_TARGET); 174 break; 175 case VIRTIO_SCSI_S_RESET: 176 set_host_byte(sc, DID_RESET); 177 break; 178 case VIRTIO_SCSI_S_BUSY: 179 set_host_byte(sc, DID_BUS_BUSY); 180 break; 181 case VIRTIO_SCSI_S_TRANSPORT_FAILURE: 182 set_host_byte(sc, DID_TRANSPORT_DISRUPTED); 183 break; 184 case VIRTIO_SCSI_S_TARGET_FAILURE: 185 set_host_byte(sc, DID_TARGET_FAILURE); 186 break; 187 case VIRTIO_SCSI_S_NEXUS_FAILURE: 188 set_host_byte(sc, DID_NEXUS_FAILURE); 189 break; 190 default: 191 scmd_printk(KERN_WARNING, sc, "Unknown response %d", 192 resp->response); 193 /* fall through */ 194 case VIRTIO_SCSI_S_FAILURE: 195 set_host_byte(sc, DID_ERROR); 196 break; 197 } 198 199 WARN_ON(resp->sense_len > VIRTIO_SCSI_SENSE_SIZE); 200 if (sc->sense_buffer) { 201 memcpy(sc->sense_buffer, resp->sense, 202 min_t(u32, resp->sense_len, VIRTIO_SCSI_SENSE_SIZE)); 203 if (resp->sense_len) 204 set_driver_byte(sc, DRIVER_SENSE); 205 } 206 207 mempool_free(cmd, virtscsi_cmd_pool); 208 sc->scsi_done(sc); 209 210 atomic_dec(&tgt->reqs); 211 } 212 213 static void virtscsi_vq_done(struct virtio_scsi *vscsi, 214 struct virtio_scsi_vq *virtscsi_vq, 215 void (*fn)(struct virtio_scsi *vscsi, void *buf)) 216 { 217 void *buf; 218 unsigned int len; 219 unsigned long flags; 220 struct virtqueue *vq = virtscsi_vq->vq; 221 222 spin_lock_irqsave(&virtscsi_vq->vq_lock, flags); 223 do { 224 virtqueue_disable_cb(vq); 225 while ((buf = virtqueue_get_buf(vq, &len)) != NULL) 226 fn(vscsi, buf); 227 228 if (unlikely(virtqueue_is_broken(vq))) 229 break; 230 } while (!virtqueue_enable_cb(vq)); 231 spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags); 232 } 233 234 static void virtscsi_req_done(struct virtqueue *vq) 235 { 236 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev); 237 struct virtio_scsi *vscsi = shost_priv(sh); 238 int index = vq->index - VIRTIO_SCSI_VQ_BASE; 239 struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index]; 240 241 /* 242 * Read req_vq before decrementing the reqs field in 243 * virtscsi_complete_cmd. 244 * 245 * With barriers: 246 * 247 * CPU #0 virtscsi_queuecommand_multi (CPU #1) 248 * ------------------------------------------------------------ 249 * lock vq_lock 250 * read req_vq 251 * read reqs (reqs = 1) 252 * write reqs (reqs = 0) 253 * increment reqs (reqs = 1) 254 * write req_vq 255 * 256 * Possible reordering without barriers: 257 * 258 * CPU #0 virtscsi_queuecommand_multi (CPU #1) 259 * ------------------------------------------------------------ 260 * lock vq_lock 261 * read reqs (reqs = 1) 262 * write reqs (reqs = 0) 263 * increment reqs (reqs = 1) 264 * write req_vq 265 * read (wrong) req_vq 266 * 267 * We do not need a full smp_rmb, because req_vq is required to get 268 * to tgt->reqs: tgt is &vscsi->tgt[sc->device->id], where sc is stored 269 * in the virtqueue as the user token. 270 */ 271 smp_read_barrier_depends(); 272 273 virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd); 274 }; 275 276 static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf) 277 { 278 struct virtio_scsi_cmd *cmd = buf; 279 280 if (cmd->comp) 281 complete_all(cmd->comp); 282 else 283 mempool_free(cmd, virtscsi_cmd_pool); 284 } 285 286 static void virtscsi_ctrl_done(struct virtqueue *vq) 287 { 288 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev); 289 struct virtio_scsi *vscsi = shost_priv(sh); 290 291 virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free); 292 }; 293 294 static int virtscsi_kick_event(struct virtio_scsi *vscsi, 295 struct virtio_scsi_event_node *event_node) 296 { 297 int err; 298 struct scatterlist sg; 299 unsigned long flags; 300 301 sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event)); 302 303 spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags); 304 305 err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node, 306 GFP_ATOMIC); 307 if (!err) 308 virtqueue_kick(vscsi->event_vq.vq); 309 310 spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags); 311 312 return err; 313 } 314 315 static int virtscsi_kick_event_all(struct virtio_scsi *vscsi) 316 { 317 int i; 318 319 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) { 320 vscsi->event_list[i].vscsi = vscsi; 321 virtscsi_kick_event(vscsi, &vscsi->event_list[i]); 322 } 323 324 return 0; 325 } 326 327 static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi) 328 { 329 int i; 330 331 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) 332 cancel_work_sync(&vscsi->event_list[i].work); 333 } 334 335 static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi, 336 struct virtio_scsi_event *event) 337 { 338 struct scsi_device *sdev; 339 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev); 340 unsigned int target = event->lun[1]; 341 unsigned int lun = (event->lun[2] << 8) | event->lun[3]; 342 343 switch (event->reason) { 344 case VIRTIO_SCSI_EVT_RESET_RESCAN: 345 scsi_add_device(shost, 0, target, lun); 346 break; 347 case VIRTIO_SCSI_EVT_RESET_REMOVED: 348 sdev = scsi_device_lookup(shost, 0, target, lun); 349 if (sdev) { 350 scsi_remove_device(sdev); 351 scsi_device_put(sdev); 352 } else { 353 pr_err("SCSI device %d 0 %d %d not found\n", 354 shost->host_no, target, lun); 355 } 356 break; 357 default: 358 pr_info("Unsupport virtio scsi event reason %x\n", event->reason); 359 } 360 } 361 362 static void virtscsi_handle_param_change(struct virtio_scsi *vscsi, 363 struct virtio_scsi_event *event) 364 { 365 struct scsi_device *sdev; 366 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev); 367 unsigned int target = event->lun[1]; 368 unsigned int lun = (event->lun[2] << 8) | event->lun[3]; 369 u8 asc = event->reason & 255; 370 u8 ascq = event->reason >> 8; 371 372 sdev = scsi_device_lookup(shost, 0, target, lun); 373 if (!sdev) { 374 pr_err("SCSI device %d 0 %d %d not found\n", 375 shost->host_no, target, lun); 376 return; 377 } 378 379 /* Handle "Parameters changed", "Mode parameters changed", and 380 "Capacity data has changed". */ 381 if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09)) 382 scsi_rescan_device(&sdev->sdev_gendev); 383 384 scsi_device_put(sdev); 385 } 386 387 static void virtscsi_handle_event(struct work_struct *work) 388 { 389 struct virtio_scsi_event_node *event_node = 390 container_of(work, struct virtio_scsi_event_node, work); 391 struct virtio_scsi *vscsi = event_node->vscsi; 392 struct virtio_scsi_event *event = &event_node->event; 393 394 if (event->event & VIRTIO_SCSI_T_EVENTS_MISSED) { 395 event->event &= ~VIRTIO_SCSI_T_EVENTS_MISSED; 396 scsi_scan_host(virtio_scsi_host(vscsi->vdev)); 397 } 398 399 switch (event->event) { 400 case VIRTIO_SCSI_T_NO_EVENT: 401 break; 402 case VIRTIO_SCSI_T_TRANSPORT_RESET: 403 virtscsi_handle_transport_reset(vscsi, event); 404 break; 405 case VIRTIO_SCSI_T_PARAM_CHANGE: 406 virtscsi_handle_param_change(vscsi, event); 407 break; 408 default: 409 pr_err("Unsupport virtio scsi event %x\n", event->event); 410 } 411 virtscsi_kick_event(vscsi, event_node); 412 } 413 414 static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf) 415 { 416 struct virtio_scsi_event_node *event_node = buf; 417 418 INIT_WORK(&event_node->work, virtscsi_handle_event); 419 schedule_work(&event_node->work); 420 } 421 422 static void virtscsi_event_done(struct virtqueue *vq) 423 { 424 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev); 425 struct virtio_scsi *vscsi = shost_priv(sh); 426 427 virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event); 428 }; 429 430 /** 431 * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue 432 * @vq : the struct virtqueue we're talking about 433 * @cmd : command structure 434 * @req_size : size of the request buffer 435 * @resp_size : size of the response buffer 436 * @gfp : flags to use for memory allocations 437 */ 438 static int virtscsi_add_cmd(struct virtqueue *vq, 439 struct virtio_scsi_cmd *cmd, 440 size_t req_size, size_t resp_size, gfp_t gfp) 441 { 442 struct scsi_cmnd *sc = cmd->sc; 443 struct scatterlist *sgs[4], req, resp; 444 struct sg_table *out, *in; 445 unsigned out_num = 0, in_num = 0; 446 447 out = in = NULL; 448 449 if (sc && sc->sc_data_direction != DMA_NONE) { 450 if (sc->sc_data_direction != DMA_FROM_DEVICE) 451 out = &scsi_out(sc)->table; 452 if (sc->sc_data_direction != DMA_TO_DEVICE) 453 in = &scsi_in(sc)->table; 454 } 455 456 /* Request header. */ 457 sg_init_one(&req, &cmd->req, req_size); 458 sgs[out_num++] = &req; 459 460 /* Data-out buffer. */ 461 if (out) 462 sgs[out_num++] = out->sgl; 463 464 /* Response header. */ 465 sg_init_one(&resp, &cmd->resp, resp_size); 466 sgs[out_num + in_num++] = &resp; 467 468 /* Data-in buffer */ 469 if (in) 470 sgs[out_num + in_num++] = in->sgl; 471 472 return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, gfp); 473 } 474 475 static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq, 476 struct virtio_scsi_cmd *cmd, 477 size_t req_size, size_t resp_size, gfp_t gfp) 478 { 479 unsigned long flags; 480 int err; 481 bool needs_kick = false; 482 483 spin_lock_irqsave(&vq->vq_lock, flags); 484 err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size, gfp); 485 if (!err) 486 needs_kick = virtqueue_kick_prepare(vq->vq); 487 488 spin_unlock_irqrestore(&vq->vq_lock, flags); 489 490 if (needs_kick) 491 virtqueue_notify(vq->vq); 492 return err; 493 } 494 495 static int virtscsi_queuecommand(struct virtio_scsi *vscsi, 496 struct virtio_scsi_vq *req_vq, 497 struct scsi_cmnd *sc) 498 { 499 struct virtio_scsi_cmd *cmd; 500 int ret; 501 502 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev); 503 BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize); 504 505 /* TODO: check feature bit and fail if unsupported? */ 506 BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL); 507 508 dev_dbg(&sc->device->sdev_gendev, 509 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]); 510 511 ret = SCSI_MLQUEUE_HOST_BUSY; 512 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC); 513 if (!cmd) 514 goto out; 515 516 memset(cmd, 0, sizeof(*cmd)); 517 cmd->sc = sc; 518 cmd->req.cmd = (struct virtio_scsi_cmd_req){ 519 .lun[0] = 1, 520 .lun[1] = sc->device->id, 521 .lun[2] = (sc->device->lun >> 8) | 0x40, 522 .lun[3] = sc->device->lun & 0xff, 523 .tag = (unsigned long)sc, 524 .task_attr = VIRTIO_SCSI_S_SIMPLE, 525 .prio = 0, 526 .crn = 0, 527 }; 528 529 BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE); 530 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len); 531 532 if (virtscsi_kick_cmd(req_vq, cmd, 533 sizeof cmd->req.cmd, sizeof cmd->resp.cmd, 534 GFP_ATOMIC) == 0) 535 ret = 0; 536 else 537 mempool_free(cmd, virtscsi_cmd_pool); 538 539 out: 540 return ret; 541 } 542 543 static int virtscsi_queuecommand_single(struct Scsi_Host *sh, 544 struct scsi_cmnd *sc) 545 { 546 struct virtio_scsi *vscsi = shost_priv(sh); 547 struct virtio_scsi_target_state *tgt = 548 scsi_target(sc->device)->hostdata; 549 550 atomic_inc(&tgt->reqs); 551 return virtscsi_queuecommand(vscsi, &vscsi->req_vqs[0], sc); 552 } 553 554 static struct virtio_scsi_vq *virtscsi_pick_vq(struct virtio_scsi *vscsi, 555 struct virtio_scsi_target_state *tgt) 556 { 557 struct virtio_scsi_vq *vq; 558 unsigned long flags; 559 u32 queue_num; 560 561 spin_lock_irqsave(&tgt->tgt_lock, flags); 562 563 /* 564 * The memory barrier after atomic_inc_return matches 565 * the smp_read_barrier_depends() in virtscsi_req_done. 566 */ 567 if (atomic_inc_return(&tgt->reqs) > 1) 568 vq = ACCESS_ONCE(tgt->req_vq); 569 else { 570 queue_num = smp_processor_id(); 571 while (unlikely(queue_num >= vscsi->num_queues)) 572 queue_num -= vscsi->num_queues; 573 574 tgt->req_vq = vq = &vscsi->req_vqs[queue_num]; 575 } 576 577 spin_unlock_irqrestore(&tgt->tgt_lock, flags); 578 return vq; 579 } 580 581 static int virtscsi_queuecommand_multi(struct Scsi_Host *sh, 582 struct scsi_cmnd *sc) 583 { 584 struct virtio_scsi *vscsi = shost_priv(sh); 585 struct virtio_scsi_target_state *tgt = 586 scsi_target(sc->device)->hostdata; 587 struct virtio_scsi_vq *req_vq = virtscsi_pick_vq(vscsi, tgt); 588 589 return virtscsi_queuecommand(vscsi, req_vq, sc); 590 } 591 592 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd) 593 { 594 DECLARE_COMPLETION_ONSTACK(comp); 595 int ret = FAILED; 596 597 cmd->comp = ∁ 598 if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd, 599 sizeof cmd->req.tmf, sizeof cmd->resp.tmf, 600 GFP_NOIO) < 0) 601 goto out; 602 603 wait_for_completion(&comp); 604 if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK || 605 cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED) 606 ret = SUCCESS; 607 608 out: 609 mempool_free(cmd, virtscsi_cmd_pool); 610 return ret; 611 } 612 613 static int virtscsi_device_reset(struct scsi_cmnd *sc) 614 { 615 struct virtio_scsi *vscsi = shost_priv(sc->device->host); 616 struct virtio_scsi_cmd *cmd; 617 618 sdev_printk(KERN_INFO, sc->device, "device reset\n"); 619 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO); 620 if (!cmd) 621 return FAILED; 622 623 memset(cmd, 0, sizeof(*cmd)); 624 cmd->sc = sc; 625 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){ 626 .type = VIRTIO_SCSI_T_TMF, 627 .subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET, 628 .lun[0] = 1, 629 .lun[1] = sc->device->id, 630 .lun[2] = (sc->device->lun >> 8) | 0x40, 631 .lun[3] = sc->device->lun & 0xff, 632 }; 633 return virtscsi_tmf(vscsi, cmd); 634 } 635 636 static int virtscsi_abort(struct scsi_cmnd *sc) 637 { 638 struct virtio_scsi *vscsi = shost_priv(sc->device->host); 639 struct virtio_scsi_cmd *cmd; 640 641 scmd_printk(KERN_INFO, sc, "abort\n"); 642 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO); 643 if (!cmd) 644 return FAILED; 645 646 memset(cmd, 0, sizeof(*cmd)); 647 cmd->sc = sc; 648 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){ 649 .type = VIRTIO_SCSI_T_TMF, 650 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK, 651 .lun[0] = 1, 652 .lun[1] = sc->device->id, 653 .lun[2] = (sc->device->lun >> 8) | 0x40, 654 .lun[3] = sc->device->lun & 0xff, 655 .tag = (unsigned long)sc, 656 }; 657 return virtscsi_tmf(vscsi, cmd); 658 } 659 660 static int virtscsi_target_alloc(struct scsi_target *starget) 661 { 662 struct virtio_scsi_target_state *tgt = 663 kmalloc(sizeof(*tgt), GFP_KERNEL); 664 if (!tgt) 665 return -ENOMEM; 666 667 spin_lock_init(&tgt->tgt_lock); 668 atomic_set(&tgt->reqs, 0); 669 tgt->req_vq = NULL; 670 671 starget->hostdata = tgt; 672 return 0; 673 } 674 675 static void virtscsi_target_destroy(struct scsi_target *starget) 676 { 677 struct virtio_scsi_target_state *tgt = starget->hostdata; 678 kfree(tgt); 679 } 680 681 static struct scsi_host_template virtscsi_host_template_single = { 682 .module = THIS_MODULE, 683 .name = "Virtio SCSI HBA", 684 .proc_name = "virtio_scsi", 685 .this_id = -1, 686 .queuecommand = virtscsi_queuecommand_single, 687 .eh_abort_handler = virtscsi_abort, 688 .eh_device_reset_handler = virtscsi_device_reset, 689 690 .can_queue = 1024, 691 .dma_boundary = UINT_MAX, 692 .use_clustering = ENABLE_CLUSTERING, 693 .target_alloc = virtscsi_target_alloc, 694 .target_destroy = virtscsi_target_destroy, 695 }; 696 697 static struct scsi_host_template virtscsi_host_template_multi = { 698 .module = THIS_MODULE, 699 .name = "Virtio SCSI HBA", 700 .proc_name = "virtio_scsi", 701 .this_id = -1, 702 .queuecommand = virtscsi_queuecommand_multi, 703 .eh_abort_handler = virtscsi_abort, 704 .eh_device_reset_handler = virtscsi_device_reset, 705 706 .can_queue = 1024, 707 .dma_boundary = UINT_MAX, 708 .use_clustering = ENABLE_CLUSTERING, 709 .target_alloc = virtscsi_target_alloc, 710 .target_destroy = virtscsi_target_destroy, 711 }; 712 713 #define virtscsi_config_get(vdev, fld) \ 714 ({ \ 715 typeof(((struct virtio_scsi_config *)0)->fld) __val; \ 716 virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \ 717 __val; \ 718 }) 719 720 #define virtscsi_config_set(vdev, fld, val) \ 721 do { \ 722 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \ 723 virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \ 724 } while(0) 725 726 static void __virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity) 727 { 728 int i; 729 int cpu; 730 731 /* In multiqueue mode, when the number of cpu is equal 732 * to the number of request queues, we let the qeueues 733 * to be private to one cpu by setting the affinity hint 734 * to eliminate the contention. 735 */ 736 if ((vscsi->num_queues == 1 || 737 vscsi->num_queues != num_online_cpus()) && affinity) { 738 if (vscsi->affinity_hint_set) 739 affinity = false; 740 else 741 return; 742 } 743 744 if (affinity) { 745 i = 0; 746 for_each_online_cpu(cpu) { 747 virtqueue_set_affinity(vscsi->req_vqs[i].vq, cpu); 748 i++; 749 } 750 751 vscsi->affinity_hint_set = true; 752 } else { 753 for (i = 0; i < vscsi->num_queues; i++) { 754 if (!vscsi->req_vqs[i].vq) 755 continue; 756 757 virtqueue_set_affinity(vscsi->req_vqs[i].vq, -1); 758 } 759 760 vscsi->affinity_hint_set = false; 761 } 762 } 763 764 static void virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity) 765 { 766 get_online_cpus(); 767 __virtscsi_set_affinity(vscsi, affinity); 768 put_online_cpus(); 769 } 770 771 static int virtscsi_cpu_callback(struct notifier_block *nfb, 772 unsigned long action, void *hcpu) 773 { 774 struct virtio_scsi *vscsi = container_of(nfb, struct virtio_scsi, nb); 775 switch(action) { 776 case CPU_ONLINE: 777 case CPU_ONLINE_FROZEN: 778 case CPU_DEAD: 779 case CPU_DEAD_FROZEN: 780 __virtscsi_set_affinity(vscsi, true); 781 break; 782 default: 783 break; 784 } 785 return NOTIFY_OK; 786 } 787 788 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq, 789 struct virtqueue *vq) 790 { 791 spin_lock_init(&virtscsi_vq->vq_lock); 792 virtscsi_vq->vq = vq; 793 } 794 795 static void virtscsi_scan(struct virtio_device *vdev) 796 { 797 struct Scsi_Host *shost = (struct Scsi_Host *)vdev->priv; 798 799 scsi_scan_host(shost); 800 } 801 802 static void virtscsi_remove_vqs(struct virtio_device *vdev) 803 { 804 struct Scsi_Host *sh = virtio_scsi_host(vdev); 805 struct virtio_scsi *vscsi = shost_priv(sh); 806 807 virtscsi_set_affinity(vscsi, false); 808 809 /* Stop all the virtqueues. */ 810 vdev->config->reset(vdev); 811 812 vdev->config->del_vqs(vdev); 813 } 814 815 static int virtscsi_init(struct virtio_device *vdev, 816 struct virtio_scsi *vscsi) 817 { 818 int err; 819 u32 i; 820 u32 num_vqs; 821 vq_callback_t **callbacks; 822 const char **names; 823 struct virtqueue **vqs; 824 825 num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE; 826 vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL); 827 callbacks = kmalloc(num_vqs * sizeof(vq_callback_t *), GFP_KERNEL); 828 names = kmalloc(num_vqs * sizeof(char *), GFP_KERNEL); 829 830 if (!callbacks || !vqs || !names) { 831 err = -ENOMEM; 832 goto out; 833 } 834 835 callbacks[0] = virtscsi_ctrl_done; 836 callbacks[1] = virtscsi_event_done; 837 names[0] = "control"; 838 names[1] = "event"; 839 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) { 840 callbacks[i] = virtscsi_req_done; 841 names[i] = "request"; 842 } 843 844 /* Discover virtqueues and write information to configuration. */ 845 err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names); 846 if (err) 847 goto out; 848 849 virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]); 850 virtscsi_init_vq(&vscsi->event_vq, vqs[1]); 851 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) 852 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE], 853 vqs[i]); 854 855 virtscsi_set_affinity(vscsi, true); 856 857 virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE); 858 virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE); 859 860 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) 861 virtscsi_kick_event_all(vscsi); 862 863 err = 0; 864 865 out: 866 kfree(names); 867 kfree(callbacks); 868 kfree(vqs); 869 if (err) 870 virtscsi_remove_vqs(vdev); 871 return err; 872 } 873 874 static int virtscsi_probe(struct virtio_device *vdev) 875 { 876 struct Scsi_Host *shost; 877 struct virtio_scsi *vscsi; 878 int err; 879 u32 sg_elems, num_targets; 880 u32 cmd_per_lun; 881 u32 num_queues; 882 struct scsi_host_template *hostt; 883 884 /* We need to know how many queues before we allocate. */ 885 num_queues = virtscsi_config_get(vdev, num_queues) ? : 1; 886 887 num_targets = virtscsi_config_get(vdev, max_target) + 1; 888 889 if (num_queues == 1) 890 hostt = &virtscsi_host_template_single; 891 else 892 hostt = &virtscsi_host_template_multi; 893 894 shost = scsi_host_alloc(hostt, 895 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues); 896 if (!shost) 897 return -ENOMEM; 898 899 sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1; 900 shost->sg_tablesize = sg_elems; 901 vscsi = shost_priv(shost); 902 vscsi->vdev = vdev; 903 vscsi->num_queues = num_queues; 904 vdev->priv = shost; 905 906 err = virtscsi_init(vdev, vscsi); 907 if (err) 908 goto virtscsi_init_failed; 909 910 vscsi->nb.notifier_call = &virtscsi_cpu_callback; 911 err = register_hotcpu_notifier(&vscsi->nb); 912 if (err) { 913 pr_err("registering cpu notifier failed\n"); 914 goto scsi_add_host_failed; 915 } 916 917 cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1; 918 shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue); 919 shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF; 920 921 /* LUNs > 256 are reported with format 1, so they go in the range 922 * 16640-32767. 923 */ 924 shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000; 925 shost->max_id = num_targets; 926 shost->max_channel = 0; 927 shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE; 928 err = scsi_add_host(shost, &vdev->dev); 929 if (err) 930 goto scsi_add_host_failed; 931 /* 932 * scsi_scan_host() happens in virtscsi_scan() via virtio_driver->scan() 933 * after VIRTIO_CONFIG_S_DRIVER_OK has been set.. 934 */ 935 return 0; 936 937 scsi_add_host_failed: 938 vdev->config->del_vqs(vdev); 939 virtscsi_init_failed: 940 scsi_host_put(shost); 941 return err; 942 } 943 944 static void virtscsi_remove(struct virtio_device *vdev) 945 { 946 struct Scsi_Host *shost = virtio_scsi_host(vdev); 947 struct virtio_scsi *vscsi = shost_priv(shost); 948 949 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) 950 virtscsi_cancel_event_work(vscsi); 951 952 scsi_remove_host(shost); 953 954 unregister_hotcpu_notifier(&vscsi->nb); 955 956 virtscsi_remove_vqs(vdev); 957 scsi_host_put(shost); 958 } 959 960 #ifdef CONFIG_PM_SLEEP 961 static int virtscsi_freeze(struct virtio_device *vdev) 962 { 963 struct Scsi_Host *sh = virtio_scsi_host(vdev); 964 struct virtio_scsi *vscsi = shost_priv(sh); 965 966 unregister_hotcpu_notifier(&vscsi->nb); 967 virtscsi_remove_vqs(vdev); 968 return 0; 969 } 970 971 static int virtscsi_restore(struct virtio_device *vdev) 972 { 973 struct Scsi_Host *sh = virtio_scsi_host(vdev); 974 struct virtio_scsi *vscsi = shost_priv(sh); 975 int err; 976 977 err = virtscsi_init(vdev, vscsi); 978 if (err) 979 return err; 980 981 err = register_hotcpu_notifier(&vscsi->nb); 982 if (err) 983 vdev->config->del_vqs(vdev); 984 985 return err; 986 } 987 #endif 988 989 static struct virtio_device_id id_table[] = { 990 { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID }, 991 { 0 }, 992 }; 993 994 static unsigned int features[] = { 995 VIRTIO_SCSI_F_HOTPLUG, 996 VIRTIO_SCSI_F_CHANGE, 997 }; 998 999 static struct virtio_driver virtio_scsi_driver = { 1000 .feature_table = features, 1001 .feature_table_size = ARRAY_SIZE(features), 1002 .driver.name = KBUILD_MODNAME, 1003 .driver.owner = THIS_MODULE, 1004 .id_table = id_table, 1005 .probe = virtscsi_probe, 1006 .scan = virtscsi_scan, 1007 #ifdef CONFIG_PM_SLEEP 1008 .freeze = virtscsi_freeze, 1009 .restore = virtscsi_restore, 1010 #endif 1011 .remove = virtscsi_remove, 1012 }; 1013 1014 static int __init init(void) 1015 { 1016 int ret = -ENOMEM; 1017 1018 virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0); 1019 if (!virtscsi_cmd_cache) { 1020 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n"); 1021 goto error; 1022 } 1023 1024 1025 virtscsi_cmd_pool = 1026 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ, 1027 virtscsi_cmd_cache); 1028 if (!virtscsi_cmd_pool) { 1029 pr_err("mempool_create() for virtscsi_cmd_pool failed\n"); 1030 goto error; 1031 } 1032 ret = register_virtio_driver(&virtio_scsi_driver); 1033 if (ret < 0) 1034 goto error; 1035 1036 return 0; 1037 1038 error: 1039 if (virtscsi_cmd_pool) { 1040 mempool_destroy(virtscsi_cmd_pool); 1041 virtscsi_cmd_pool = NULL; 1042 } 1043 if (virtscsi_cmd_cache) { 1044 kmem_cache_destroy(virtscsi_cmd_cache); 1045 virtscsi_cmd_cache = NULL; 1046 } 1047 return ret; 1048 } 1049 1050 static void __exit fini(void) 1051 { 1052 unregister_virtio_driver(&virtio_scsi_driver); 1053 mempool_destroy(virtscsi_cmd_pool); 1054 kmem_cache_destroy(virtscsi_cmd_cache); 1055 } 1056 module_init(init); 1057 module_exit(fini); 1058 1059 MODULE_DEVICE_TABLE(virtio, id_table); 1060 MODULE_DESCRIPTION("Virtio SCSI HBA driver"); 1061 MODULE_LICENSE("GPL"); 1062