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Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney...
[linux-2.6.git] / drivers / scsi / virtio_scsi.c
blob2168258fb2c3a2cf5374a3592a302062d75bb305
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 } while (!virtqueue_enable_cb(vq));
228 spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
229 }
230
231 static void virtscsi_req_done(struct virtqueue *vq)
232 {
233 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
234 struct virtio_scsi *vscsi = shost_priv(sh);
235 int index = vq->index - VIRTIO_SCSI_VQ_BASE;
236 struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
237
238 /*
239 * Read req_vq before decrementing the reqs field in
240 * virtscsi_complete_cmd.
241 *
242 * With barriers:
243 *
244 * CPU #0 virtscsi_queuecommand_multi (CPU #1)
245 * ------------------------------------------------------------
246 * lock vq_lock
247 * read req_vq
248 * read reqs (reqs = 1)
249 * write reqs (reqs = 0)
250 * increment reqs (reqs = 1)
251 * write req_vq
252 *
253 * Possible reordering without barriers:
254 *
255 * CPU #0 virtscsi_queuecommand_multi (CPU #1)
256 * ------------------------------------------------------------
257 * lock vq_lock
258 * read reqs (reqs = 1)
259 * write reqs (reqs = 0)
260 * increment reqs (reqs = 1)
261 * write req_vq
262 * read (wrong) req_vq
263 *
264 * We do not need a full smp_rmb, because req_vq is required to get
265 * to tgt->reqs: tgt is &vscsi->tgt[sc->device->id], where sc is stored
266 * in the virtqueue as the user token.
267 */
268 smp_read_barrier_depends();
269
270 virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
271 };
272
273 static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
274 {
275 struct virtio_scsi_cmd *cmd = buf;
276
277 if (cmd->comp)
278 complete_all(cmd->comp);
279 else
280 mempool_free(cmd, virtscsi_cmd_pool);
281 }
282
283 static void virtscsi_ctrl_done(struct virtqueue *vq)
284 {
285 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
286 struct virtio_scsi *vscsi = shost_priv(sh);
287
288 virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
289 };
290
291 static int virtscsi_kick_event(struct virtio_scsi *vscsi,
292 struct virtio_scsi_event_node *event_node)
293 {
294 int err;
295 struct scatterlist sg;
296 unsigned long flags;
297
298 sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
299
300 spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
301
302 err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
303 GFP_ATOMIC);
304 if (!err)
305 virtqueue_kick(vscsi->event_vq.vq);
306
307 spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
308
309 return err;
310 }
311
312 static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
313 {
314 int i;
315
316 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
317 vscsi->event_list[i].vscsi = vscsi;
318 virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
319 }
320
321 return 0;
322 }
323
324 static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
325 {
326 int i;
327
328 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
329 cancel_work_sync(&vscsi->event_list[i].work);
330 }
331
332 static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
333 struct virtio_scsi_event *event)
334 {
335 struct scsi_device *sdev;
336 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
337 unsigned int target = event->lun[1];
338 unsigned int lun = (event->lun[2] << 8) | event->lun[3];
339
340 switch (event->reason) {
341 case VIRTIO_SCSI_EVT_RESET_RESCAN:
342 scsi_add_device(shost, 0, target, lun);
343 break;
344 case VIRTIO_SCSI_EVT_RESET_REMOVED:
345 sdev = scsi_device_lookup(shost, 0, target, lun);
346 if (sdev) {
347 scsi_remove_device(sdev);
348 scsi_device_put(sdev);
349 } else {
350 pr_err("SCSI device %d 0 %d %d not found\n",
351 shost->host_no, target, lun);
352 }
353 break;
354 default:
355 pr_info("Unsupport virtio scsi event reason %x\n", event->reason);
356 }
357 }
358
359 static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
360 struct virtio_scsi_event *event)
361 {
362 struct scsi_device *sdev;
363 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
364 unsigned int target = event->lun[1];
365 unsigned int lun = (event->lun[2] << 8) | event->lun[3];
366 u8 asc = event->reason & 255;
367 u8 ascq = event->reason >> 8;
368
369 sdev = scsi_device_lookup(shost, 0, target, lun);
370 if (!sdev) {
371 pr_err("SCSI device %d 0 %d %d not found\n",
372 shost->host_no, target, lun);
373 return;
374 }
375
376 /* Handle "Parameters changed", "Mode parameters changed", and
377 "Capacity data has changed". */
378 if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
379 scsi_rescan_device(&sdev->sdev_gendev);
380
381 scsi_device_put(sdev);
382 }
383
384 static void virtscsi_handle_event(struct work_struct *work)
385 {
386 struct virtio_scsi_event_node *event_node =
387 container_of(work, struct virtio_scsi_event_node, work);
388 struct virtio_scsi *vscsi = event_node->vscsi;
389 struct virtio_scsi_event *event = &event_node->event;
390
391 if (event->event & VIRTIO_SCSI_T_EVENTS_MISSED) {
392 event->event &= ~VIRTIO_SCSI_T_EVENTS_MISSED;
393 scsi_scan_host(virtio_scsi_host(vscsi->vdev));
394 }
395
396 switch (event->event) {
397 case VIRTIO_SCSI_T_NO_EVENT:
398 break;
399 case VIRTIO_SCSI_T_TRANSPORT_RESET:
400 virtscsi_handle_transport_reset(vscsi, event);
401 break;
402 case VIRTIO_SCSI_T_PARAM_CHANGE:
403 virtscsi_handle_param_change(vscsi, event);
404 break;
405 default:
406 pr_err("Unsupport virtio scsi event %x\n", event->event);
407 }
408 virtscsi_kick_event(vscsi, event_node);
409 }
410
411 static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
412 {
413 struct virtio_scsi_event_node *event_node = buf;
414
415 INIT_WORK(&event_node->work, virtscsi_handle_event);
416 schedule_work(&event_node->work);
417 }
418
419 static void virtscsi_event_done(struct virtqueue *vq)
420 {
421 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
422 struct virtio_scsi *vscsi = shost_priv(sh);
423
424 virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
425 };
426
427 /**
428 * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue
429 * @vq : the struct virtqueue we're talking about
430 * @cmd : command structure
431 * @req_size : size of the request buffer
432 * @resp_size : size of the response buffer
433 * @gfp : flags to use for memory allocations
434 */
435 static int virtscsi_add_cmd(struct virtqueue *vq,
436 struct virtio_scsi_cmd *cmd,
437 size_t req_size, size_t resp_size, gfp_t gfp)
438 {
439 struct scsi_cmnd *sc = cmd->sc;
440 struct scatterlist *sgs[4], req, resp;
441 struct sg_table *out, *in;
442 unsigned out_num = 0, in_num = 0;
443
444 out = in = NULL;
445
446 if (sc && sc->sc_data_direction != DMA_NONE) {
447 if (sc->sc_data_direction != DMA_FROM_DEVICE)
448 out = &scsi_out(sc)->table;
449 if (sc->sc_data_direction != DMA_TO_DEVICE)
450 in = &scsi_in(sc)->table;
451 }
452
453 /* Request header. */
454 sg_init_one(&req, &cmd->req, req_size);
455 sgs[out_num++] = &req;
456
457 /* Data-out buffer. */
458 if (out)
459 sgs[out_num++] = out->sgl;
460
461 /* Response header. */
462 sg_init_one(&resp, &cmd->resp, resp_size);
463 sgs[out_num + in_num++] = &resp;
464
465 /* Data-in buffer */
466 if (in)
467 sgs[out_num + in_num++] = in->sgl;
468
469 return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, gfp);
470 }
471
472 static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq,
473 struct virtio_scsi_cmd *cmd,
474 size_t req_size, size_t resp_size, gfp_t gfp)
475 {
476 unsigned long flags;
477 int err;
478 bool needs_kick = false;
479
480 spin_lock_irqsave(&vq->vq_lock, flags);
481 err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size, gfp);
482 if (!err)
483 needs_kick = virtqueue_kick_prepare(vq->vq);
484
485 spin_unlock_irqrestore(&vq->vq_lock, flags);
486
487 if (needs_kick)
488 virtqueue_notify(vq->vq);
489 return err;
490 }
491
492 static int virtscsi_queuecommand(struct virtio_scsi *vscsi,
493 struct virtio_scsi_vq *req_vq,
494 struct scsi_cmnd *sc)
495 {
496 struct virtio_scsi_cmd *cmd;
497 int ret;
498
499 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
500 BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
501
502 /* TODO: check feature bit and fail if unsupported? */
503 BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
504
505 dev_dbg(&sc->device->sdev_gendev,
506 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
507
508 ret = SCSI_MLQUEUE_HOST_BUSY;
509 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC);
510 if (!cmd)
511 goto out;
512
513 memset(cmd, 0, sizeof(*cmd));
514 cmd->sc = sc;
515 cmd->req.cmd = (struct virtio_scsi_cmd_req){
516 .lun[0] = 1,
517 .lun[1] = sc->device->id,
518 .lun[2] = (sc->device->lun >> 8) | 0x40,
519 .lun[3] = sc->device->lun & 0xff,
520 .tag = (unsigned long)sc,
521 .task_attr = VIRTIO_SCSI_S_SIMPLE,
522 .prio = 0,
523 .crn = 0,
524 };
525
526 BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
527 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
528
529 if (virtscsi_kick_cmd(req_vq, cmd,
530 sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
531 GFP_ATOMIC) == 0)
532 ret = 0;
533 else
534 mempool_free(cmd, virtscsi_cmd_pool);
535
536 out:
537 return ret;
538 }
539
540 static int virtscsi_queuecommand_single(struct Scsi_Host *sh,
541 struct scsi_cmnd *sc)
542 {
543 struct virtio_scsi *vscsi = shost_priv(sh);
544 struct virtio_scsi_target_state *tgt =
545 scsi_target(sc->device)->hostdata;
546
547 atomic_inc(&tgt->reqs);
548 return virtscsi_queuecommand(vscsi, &vscsi->req_vqs[0], sc);
549 }
550
551 static struct virtio_scsi_vq *virtscsi_pick_vq(struct virtio_scsi *vscsi,
552 struct virtio_scsi_target_state *tgt)
553 {
554 struct virtio_scsi_vq *vq;
555 unsigned long flags;
556 u32 queue_num;
557
558 spin_lock_irqsave(&tgt->tgt_lock, flags);
559
560 /*
561 * The memory barrier after atomic_inc_return matches
562 * the smp_read_barrier_depends() in virtscsi_req_done.
563 */
564 if (atomic_inc_return(&tgt->reqs) > 1)
565 vq = ACCESS_ONCE(tgt->req_vq);
566 else {
567 queue_num = smp_processor_id();
568 while (unlikely(queue_num >= vscsi->num_queues))
569 queue_num -= vscsi->num_queues;
570
571 tgt->req_vq = vq = &vscsi->req_vqs[queue_num];
572 }
573
574 spin_unlock_irqrestore(&tgt->tgt_lock, flags);
575 return vq;
576 }
577
578 static int virtscsi_queuecommand_multi(struct Scsi_Host *sh,
579 struct scsi_cmnd *sc)
580 {
581 struct virtio_scsi *vscsi = shost_priv(sh);
582 struct virtio_scsi_target_state *tgt =
583 scsi_target(sc->device)->hostdata;
584 struct virtio_scsi_vq *req_vq = virtscsi_pick_vq(vscsi, tgt);
585
586 return virtscsi_queuecommand(vscsi, req_vq, sc);
587 }
588
589 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
590 {
591 DECLARE_COMPLETION_ONSTACK(comp);
592 int ret = FAILED;
593
594 cmd->comp = &comp;
595 if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd,
596 sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
597 GFP_NOIO) < 0)
598 goto out;
599
600 wait_for_completion(&comp);
601 if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
602 cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
603 ret = SUCCESS;
604
605 out:
606 mempool_free(cmd, virtscsi_cmd_pool);
607 return ret;
608 }
609
610 static int virtscsi_device_reset(struct scsi_cmnd *sc)
611 {
612 struct virtio_scsi *vscsi = shost_priv(sc->device->host);
613 struct virtio_scsi_cmd *cmd;
614
615 sdev_printk(KERN_INFO, sc->device, "device reset\n");
616 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
617 if (!cmd)
618 return FAILED;
619
620 memset(cmd, 0, sizeof(*cmd));
621 cmd->sc = sc;
622 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
623 .type = VIRTIO_SCSI_T_TMF,
624 .subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET,
625 .lun[0] = 1,
626 .lun[1] = sc->device->id,
627 .lun[2] = (sc->device->lun >> 8) | 0x40,
628 .lun[3] = sc->device->lun & 0xff,
629 };
630 return virtscsi_tmf(vscsi, cmd);
631 }
632
633 static int virtscsi_abort(struct scsi_cmnd *sc)
634 {
635 struct virtio_scsi *vscsi = shost_priv(sc->device->host);
636 struct virtio_scsi_cmd *cmd;
637
638 scmd_printk(KERN_INFO, sc, "abort\n");
639 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
640 if (!cmd)
641 return FAILED;
642
643 memset(cmd, 0, sizeof(*cmd));
644 cmd->sc = sc;
645 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
646 .type = VIRTIO_SCSI_T_TMF,
647 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
648 .lun[0] = 1,
649 .lun[1] = sc->device->id,
650 .lun[2] = (sc->device->lun >> 8) | 0x40,
651 .lun[3] = sc->device->lun & 0xff,
652 .tag = (unsigned long)sc,
653 };
654 return virtscsi_tmf(vscsi, cmd);
655 }
656
657 static int virtscsi_target_alloc(struct scsi_target *starget)
658 {
659 struct virtio_scsi_target_state *tgt =
660 kmalloc(sizeof(*tgt), GFP_KERNEL);
661 if (!tgt)
662 return -ENOMEM;
663
664 spin_lock_init(&tgt->tgt_lock);
665 atomic_set(&tgt->reqs, 0);
666 tgt->req_vq = NULL;
667
668 starget->hostdata = tgt;
669 return 0;
670 }
671
672 static void virtscsi_target_destroy(struct scsi_target *starget)
673 {
674 struct virtio_scsi_target_state *tgt = starget->hostdata;
675 kfree(tgt);
676 }
677
678 static struct scsi_host_template virtscsi_host_template_single = {
679 .module = THIS_MODULE,
680 .name = "Virtio SCSI HBA",
681 .proc_name = "virtio_scsi",
682 .this_id = -1,
683 .queuecommand = virtscsi_queuecommand_single,
684 .eh_abort_handler = virtscsi_abort,
685 .eh_device_reset_handler = virtscsi_device_reset,
686
687 .can_queue = 1024,
688 .dma_boundary = UINT_MAX,
689 .use_clustering = ENABLE_CLUSTERING,
690 .target_alloc = virtscsi_target_alloc,
691 .target_destroy = virtscsi_target_destroy,
692 };
693
694 static struct scsi_host_template virtscsi_host_template_multi = {
695 .module = THIS_MODULE,
696 .name = "Virtio SCSI HBA",
697 .proc_name = "virtio_scsi",
698 .this_id = -1,
699 .queuecommand = virtscsi_queuecommand_multi,
700 .eh_abort_handler = virtscsi_abort,
701 .eh_device_reset_handler = virtscsi_device_reset,
702
703 .can_queue = 1024,
704 .dma_boundary = UINT_MAX,
705 .use_clustering = ENABLE_CLUSTERING,
706 .target_alloc = virtscsi_target_alloc,
707 .target_destroy = virtscsi_target_destroy,
708 };
709
710 #define virtscsi_config_get(vdev, fld) \
711 ({ \
712 typeof(((struct virtio_scsi_config *)0)->fld) __val; \
713 vdev->config->get(vdev, \
714 offsetof(struct virtio_scsi_config, fld), \
715 &__val, sizeof(__val)); \
716 __val; \
717 })
718
719 #define virtscsi_config_set(vdev, fld, val) \
720 (void)({ \
721 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
722 vdev->config->set(vdev, \
723 offsetof(struct virtio_scsi_config, fld), \
724 &__val, sizeof(__val)); \
725 })
726
727 static void __virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
728 {
729 int i;
730 int cpu;
731
732 /* In multiqueue mode, when the number of cpu is equal
733 * to the number of request queues, we let the qeueues
734 * to be private to one cpu by setting the affinity hint
735 * to eliminate the contention.
736 */
737 if ((vscsi->num_queues == 1 ||
738 vscsi->num_queues != num_online_cpus()) && affinity) {
739 if (vscsi->affinity_hint_set)
740 affinity = false;
741 else
742 return;
743 }
744
745 if (affinity) {
746 i = 0;
747 for_each_online_cpu(cpu) {
748 virtqueue_set_affinity(vscsi->req_vqs[i].vq, cpu);
749 i++;
750 }
751
752 vscsi->affinity_hint_set = true;
753 } else {
754 for (i = 0; i < vscsi->num_queues - VIRTIO_SCSI_VQ_BASE; i++)
755 virtqueue_set_affinity(vscsi->req_vqs[i].vq, -1);
756
757 vscsi->affinity_hint_set = false;
758 }
759 }
760
761 static void virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
762 {
763 get_online_cpus();
764 __virtscsi_set_affinity(vscsi, affinity);
765 put_online_cpus();
766 }
767
768 static int virtscsi_cpu_callback(struct notifier_block *nfb,
769 unsigned long action, void *hcpu)
770 {
771 struct virtio_scsi *vscsi = container_of(nfb, struct virtio_scsi, nb);
772 switch(action) {
773 case CPU_ONLINE:
774 case CPU_ONLINE_FROZEN:
775 case CPU_DEAD:
776 case CPU_DEAD_FROZEN:
777 __virtscsi_set_affinity(vscsi, true);
778 break;
779 default:
780 break;
781 }
782 return NOTIFY_OK;
783 }
784
785 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
786 struct virtqueue *vq)
787 {
788 spin_lock_init(&virtscsi_vq->vq_lock);
789 virtscsi_vq->vq = vq;
790 }
791
792 static void virtscsi_scan(struct virtio_device *vdev)
793 {
794 struct Scsi_Host *shost = (struct Scsi_Host *)vdev->priv;
795
796 scsi_scan_host(shost);
797 }
798
799 static void virtscsi_remove_vqs(struct virtio_device *vdev)
800 {
801 struct Scsi_Host *sh = virtio_scsi_host(vdev);
802 struct virtio_scsi *vscsi = shost_priv(sh);
803
804 virtscsi_set_affinity(vscsi, false);
805
806 /* Stop all the virtqueues. */
807 vdev->config->reset(vdev);
808
809 vdev->config->del_vqs(vdev);
810 }
811
812 static int virtscsi_init(struct virtio_device *vdev,
813 struct virtio_scsi *vscsi)
814 {
815 int err;
816 u32 i;
817 u32 num_vqs;
818 vq_callback_t **callbacks;
819 const char **names;
820 struct virtqueue **vqs;
821
822 num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
823 vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL);
824 callbacks = kmalloc(num_vqs * sizeof(vq_callback_t *), GFP_KERNEL);
825 names = kmalloc(num_vqs * sizeof(char *), GFP_KERNEL);
826
827 if (!callbacks || !vqs || !names) {
828 err = -ENOMEM;
829 goto out;
830 }
831
832 callbacks[0] = virtscsi_ctrl_done;
833 callbacks[1] = virtscsi_event_done;
834 names[0] = "control";
835 names[1] = "event";
836 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
837 callbacks[i] = virtscsi_req_done;
838 names[i] = "request";
839 }
840
841 /* Discover virtqueues and write information to configuration. */
842 err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
843 if (err)
844 goto out;
845
846 virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
847 virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
848 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
849 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
850 vqs[i]);
851
852 virtscsi_set_affinity(vscsi, true);
853
854 virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
855 virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
856
857 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
858 virtscsi_kick_event_all(vscsi);
859
860 err = 0;
861
862 out:
863 kfree(names);
864 kfree(callbacks);
865 kfree(vqs);
866 if (err)
867 virtscsi_remove_vqs(vdev);
868 return err;
869 }
870
871 static int virtscsi_probe(struct virtio_device *vdev)
872 {
873 struct Scsi_Host *shost;
874 struct virtio_scsi *vscsi;
875 int err;
876 u32 sg_elems, num_targets;
877 u32 cmd_per_lun;
878 u32 num_queues;
879 struct scsi_host_template *hostt;
880
881 /* We need to know how many queues before we allocate. */
882 num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
883
884 num_targets = virtscsi_config_get(vdev, max_target) + 1;
885
886 if (num_queues == 1)
887 hostt = &virtscsi_host_template_single;
888 else
889 hostt = &virtscsi_host_template_multi;
890
891 shost = scsi_host_alloc(hostt,
892 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues);
893 if (!shost)
894 return -ENOMEM;
895
896 sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
897 shost->sg_tablesize = sg_elems;
898 vscsi = shost_priv(shost);
899 vscsi->vdev = vdev;
900 vscsi->num_queues = num_queues;
901 vdev->priv = shost;
902
903 err = virtscsi_init(vdev, vscsi);
904 if (err)
905 goto virtscsi_init_failed;
906
907 vscsi->nb.notifier_call = &virtscsi_cpu_callback;
908 err = register_hotcpu_notifier(&vscsi->nb);
909 if (err) {
910 pr_err("registering cpu notifier failed\n");
911 goto scsi_add_host_failed;
912 }
913
914 cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
915 shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
916 shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
917
918 /* LUNs > 256 are reported with format 1, so they go in the range
919 * 16640-32767.
920 */
921 shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
922 shost->max_id = num_targets;
923 shost->max_channel = 0;
924 shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
925 err = scsi_add_host(shost, &vdev->dev);
926 if (err)
927 goto scsi_add_host_failed;
928 /*
929 * scsi_scan_host() happens in virtscsi_scan() via virtio_driver->scan()
930 * after VIRTIO_CONFIG_S_DRIVER_OK has been set..
931 */
932 return 0;
933
934 scsi_add_host_failed:
935 vdev->config->del_vqs(vdev);
936 virtscsi_init_failed:
937 scsi_host_put(shost);
938 return err;
939 }
940
941 static void virtscsi_remove(struct virtio_device *vdev)
942 {
943 struct Scsi_Host *shost = virtio_scsi_host(vdev);
944 struct virtio_scsi *vscsi = shost_priv(shost);
945
946 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
947 virtscsi_cancel_event_work(vscsi);
948
949 scsi_remove_host(shost);
950
951 unregister_hotcpu_notifier(&vscsi->nb);
952
953 virtscsi_remove_vqs(vdev);
954 scsi_host_put(shost);
955 }
956
957 #ifdef CONFIG_PM
958 static int virtscsi_freeze(struct virtio_device *vdev)
959 {
960 virtscsi_remove_vqs(vdev);
961 return 0;
962 }
963
964 static int virtscsi_restore(struct virtio_device *vdev)
965 {
966 struct Scsi_Host *sh = virtio_scsi_host(vdev);
967 struct virtio_scsi *vscsi = shost_priv(sh);
968
969 return virtscsi_init(vdev, vscsi);
970 }
971 #endif
972
973 static struct virtio_device_id id_table[] = {
974 { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
975 { 0 },
976 };
977
978 static unsigned int features[] = {
979 VIRTIO_SCSI_F_HOTPLUG,
980 VIRTIO_SCSI_F_CHANGE,
981 };
982
983 static struct virtio_driver virtio_scsi_driver = {
984 .feature_table = features,
985 .feature_table_size = ARRAY_SIZE(features),
986 .driver.name = KBUILD_MODNAME,
987 .driver.owner = THIS_MODULE,
988 .id_table = id_table,
989 .probe = virtscsi_probe,
990 .scan = virtscsi_scan,
991 #ifdef CONFIG_PM
992 .freeze = virtscsi_freeze,
993 .restore = virtscsi_restore,
994 #endif
995 .remove = virtscsi_remove,
996 };
997
998 static int __init init(void)
999 {
1000 int ret = -ENOMEM;
1001
1002 virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
1003 if (!virtscsi_cmd_cache) {
1004 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
1005 goto error;
1006 }
1007
1008
1009 virtscsi_cmd_pool =
1010 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
1011 virtscsi_cmd_cache);
1012 if (!virtscsi_cmd_pool) {
1013 pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
1014 goto error;
1015 }
1016 ret = register_virtio_driver(&virtio_scsi_driver);
1017 if (ret < 0)
1018 goto error;
1019
1020 return 0;
1021
1022 error:
1023 if (virtscsi_cmd_pool) {
1024 mempool_destroy(virtscsi_cmd_pool);
1025 virtscsi_cmd_pool = NULL;
1026 }
1027 if (virtscsi_cmd_cache) {
1028 kmem_cache_destroy(virtscsi_cmd_cache);
1029 virtscsi_cmd_cache = NULL;
1030 }
1031 return ret;
1032 }
1033
1034 static void __exit fini(void)
1035 {
1036 unregister_virtio_driver(&virtio_scsi_driver);
1037 mempool_destroy(virtscsi_cmd_pool);
1038 kmem_cache_destroy(virtscsi_cmd_cache);
1039 }
1040 module_init(init);
1041 module_exit(fini);
1042
1043 MODULE_DEVICE_TABLE(virtio, id_table);
1044 MODULE_DESCRIPTION("Virtio SCSI HBA driver");
1045 MODULE_LICENSE("GPL");
Linus' kernel tree