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[deliverable/linux.git] / drivers / scsi / virtio_scsi.c
1 /*
2 * Virtio SCSI HBA driver
3 *
4 * Copyright IBM Corp. 2010
5 * Copyright Red Hat, Inc. 2011
6 *
7 * Authors:
8 * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
9 * Paolo Bonzini <pbonzini@redhat.com>
10 *
11 * This work is licensed under the terms of the GNU GPL, version 2 or later.
12 * See the COPYING file in the top-level directory.
13 *
14 */
15
16 #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 <linux/blkdev.h>
27 #include <scsi/scsi_host.h>
28 #include <scsi/scsi_device.h>
29 #include <scsi/scsi_cmnd.h>
30 #include <scsi/scsi_tcq.h>
31 #include <linux/seqlock.h>
32
33 #define VIRTIO_SCSI_MEMPOOL_SZ 64
34 #define VIRTIO_SCSI_EVENT_LEN 8
35 #define VIRTIO_SCSI_VQ_BASE 2
36
37 /* Command queue element */
38 struct virtio_scsi_cmd {
39 struct scsi_cmnd *sc;
40 struct completion *comp;
41 union {
42 struct virtio_scsi_cmd_req cmd;
43 struct virtio_scsi_cmd_req_pi cmd_pi;
44 struct virtio_scsi_ctrl_tmf_req tmf;
45 struct virtio_scsi_ctrl_an_req an;
46 } req;
47 union {
48 struct virtio_scsi_cmd_resp cmd;
49 struct virtio_scsi_ctrl_tmf_resp tmf;
50 struct virtio_scsi_ctrl_an_resp an;
51 struct virtio_scsi_event evt;
52 } resp;
53 } ____cacheline_aligned_in_smp;
54
55 struct virtio_scsi_event_node {
56 struct virtio_scsi *vscsi;
57 struct virtio_scsi_event event;
58 struct work_struct work;
59 };
60
61 struct virtio_scsi_vq {
62 /* Protects vq */
63 spinlock_t vq_lock;
64
65 struct virtqueue *vq;
66 };
67
68 /*
69 * Per-target queue state.
70 *
71 * This struct holds the data needed by the queue steering policy. When a
72 * target is sent multiple requests, we need to drive them to the same queue so
73 * that FIFO processing order is kept. However, if a target was idle, we can
74 * choose a queue arbitrarily. In this case the queue is chosen according to
75 * the current VCPU, so the driver expects the number of request queues to be
76 * equal to the number of VCPUs. This makes it easy and fast to select the
77 * queue, and also lets the driver optimize the IRQ affinity for the virtqueues
78 * (each virtqueue's affinity is set to the CPU that "owns" the queue).
79 *
80 * tgt_seq is held to serialize reading and writing req_vq.
81 *
82 * Decrements of reqs are never concurrent with writes of req_vq: before the
83 * decrement reqs will be != 0; after the decrement the virtqueue completion
84 * routine will not use the req_vq so it can be changed by a new request.
85 * Thus they can happen outside the tgt_seq, provided of course we make reqs
86 * an atomic_t.
87 */
88 struct virtio_scsi_target_state {
89 seqcount_t tgt_seq;
90
91 /* Count of outstanding requests. */
92 atomic_t reqs;
93
94 /* Currently active virtqueue for requests sent to this target. */
95 struct virtio_scsi_vq *req_vq;
96 };
97
98 /* Driver instance state */
99 struct virtio_scsi {
100 struct virtio_device *vdev;
101
102 /* Get some buffers ready for event vq */
103 struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
104
105 u32 num_queues;
106
107 /* If the affinity hint is set for virtqueues */
108 bool affinity_hint_set;
109
110 /* CPU hotplug notifier */
111 struct notifier_block nb;
112
113 struct virtio_scsi_vq ctrl_vq;
114 struct virtio_scsi_vq event_vq;
115 struct virtio_scsi_vq req_vqs[];
116 };
117
118 static struct kmem_cache *virtscsi_cmd_cache;
119 static mempool_t *virtscsi_cmd_pool;
120
121 static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
122 {
123 return vdev->priv;
124 }
125
126 static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
127 {
128 if (!resid)
129 return;
130
131 if (!scsi_bidi_cmnd(sc)) {
132 scsi_set_resid(sc, resid);
133 return;
134 }
135
136 scsi_in(sc)->resid = min(resid, scsi_in(sc)->length);
137 scsi_out(sc)->resid = resid - scsi_in(sc)->resid;
138 }
139
140 /**
141 * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
142 *
143 * Called with vq_lock held.
144 */
145 static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
146 {
147 struct virtio_scsi_cmd *cmd = buf;
148 struct scsi_cmnd *sc = cmd->sc;
149 struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
150 struct virtio_scsi_target_state *tgt =
151 scsi_target(sc->device)->hostdata;
152
153 dev_dbg(&sc->device->sdev_gendev,
154 "cmd %p response %u status %#02x sense_len %u\n",
155 sc, resp->response, resp->status, resp->sense_len);
156
157 sc->result = resp->status;
158 virtscsi_compute_resid(sc, resp->resid);
159 switch (resp->response) {
160 case VIRTIO_SCSI_S_OK:
161 set_host_byte(sc, DID_OK);
162 break;
163 case VIRTIO_SCSI_S_OVERRUN:
164 set_host_byte(sc, DID_ERROR);
165 break;
166 case VIRTIO_SCSI_S_ABORTED:
167 set_host_byte(sc, DID_ABORT);
168 break;
169 case VIRTIO_SCSI_S_BAD_TARGET:
170 set_host_byte(sc, DID_BAD_TARGET);
171 break;
172 case VIRTIO_SCSI_S_RESET:
173 set_host_byte(sc, DID_RESET);
174 break;
175 case VIRTIO_SCSI_S_BUSY:
176 set_host_byte(sc, DID_BUS_BUSY);
177 break;
178 case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
179 set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
180 break;
181 case VIRTIO_SCSI_S_TARGET_FAILURE:
182 set_host_byte(sc, DID_TARGET_FAILURE);
183 break;
184 case VIRTIO_SCSI_S_NEXUS_FAILURE:
185 set_host_byte(sc, DID_NEXUS_FAILURE);
186 break;
187 default:
188 scmd_printk(KERN_WARNING, sc, "Unknown response %d",
189 resp->response);
190 /* fall through */
191 case VIRTIO_SCSI_S_FAILURE:
192 set_host_byte(sc, DID_ERROR);
193 break;
194 }
195
196 WARN_ON(resp->sense_len > VIRTIO_SCSI_SENSE_SIZE);
197 if (sc->sense_buffer) {
198 memcpy(sc->sense_buffer, resp->sense,
199 min_t(u32, resp->sense_len, VIRTIO_SCSI_SENSE_SIZE));
200 if (resp->sense_len)
201 set_driver_byte(sc, DRIVER_SENSE);
202 }
203
204 sc->scsi_done(sc);
205
206 atomic_dec(&tgt->reqs);
207 }
208
209 static void virtscsi_vq_done(struct virtio_scsi *vscsi,
210 struct virtio_scsi_vq *virtscsi_vq,
211 void (*fn)(struct virtio_scsi *vscsi, void *buf))
212 {
213 void *buf;
214 unsigned int len;
215 unsigned long flags;
216 struct virtqueue *vq = virtscsi_vq->vq;
217
218 spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
219 do {
220 virtqueue_disable_cb(vq);
221 while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
222 fn(vscsi, buf);
223
224 if (unlikely(virtqueue_is_broken(vq)))
225 break;
226 } while (!virtqueue_enable_cb(vq));
227 spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
228 }
229
230 static void virtscsi_req_done(struct virtqueue *vq)
231 {
232 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
233 struct virtio_scsi *vscsi = shost_priv(sh);
234 int index = vq->index - VIRTIO_SCSI_VQ_BASE;
235 struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
236
237 virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
238 };
239
240 static void virtscsi_poll_requests(struct virtio_scsi *vscsi)
241 {
242 int i, num_vqs;
243
244 num_vqs = vscsi->num_queues;
245 for (i = 0; i < num_vqs; i++)
246 virtscsi_vq_done(vscsi, &vscsi->req_vqs[i],
247 virtscsi_complete_cmd);
248 }
249
250 static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
251 {
252 struct virtio_scsi_cmd *cmd = buf;
253
254 if (cmd->comp)
255 complete_all(cmd->comp);
256 }
257
258 static void virtscsi_ctrl_done(struct virtqueue *vq)
259 {
260 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
261 struct virtio_scsi *vscsi = shost_priv(sh);
262
263 virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
264 };
265
266 static void virtscsi_handle_event(struct work_struct *work);
267
268 static int virtscsi_kick_event(struct virtio_scsi *vscsi,
269 struct virtio_scsi_event_node *event_node)
270 {
271 int err;
272 struct scatterlist sg;
273 unsigned long flags;
274
275 INIT_WORK(&event_node->work, virtscsi_handle_event);
276 sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
277
278 spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
279
280 err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
281 GFP_ATOMIC);
282 if (!err)
283 virtqueue_kick(vscsi->event_vq.vq);
284
285 spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
286
287 return err;
288 }
289
290 static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
291 {
292 int i;
293
294 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
295 vscsi->event_list[i].vscsi = vscsi;
296 virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
297 }
298
299 return 0;
300 }
301
302 static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
303 {
304 int i;
305
306 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
307 cancel_work_sync(&vscsi->event_list[i].work);
308 }
309
310 static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
311 struct virtio_scsi_event *event)
312 {
313 struct scsi_device *sdev;
314 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
315 unsigned int target = event->lun[1];
316 unsigned int lun = (event->lun[2] << 8) | event->lun[3];
317
318 switch (event->reason) {
319 case VIRTIO_SCSI_EVT_RESET_RESCAN:
320 scsi_add_device(shost, 0, target, lun);
321 break;
322 case VIRTIO_SCSI_EVT_RESET_REMOVED:
323 sdev = scsi_device_lookup(shost, 0, target, lun);
324 if (sdev) {
325 scsi_remove_device(sdev);
326 scsi_device_put(sdev);
327 } else {
328 pr_err("SCSI device %d 0 %d %d not found\n",
329 shost->host_no, target, lun);
330 }
331 break;
332 default:
333 pr_info("Unsupport virtio scsi event reason %x\n", event->reason);
334 }
335 }
336
337 static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
338 struct virtio_scsi_event *event)
339 {
340 struct scsi_device *sdev;
341 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
342 unsigned int target = event->lun[1];
343 unsigned int lun = (event->lun[2] << 8) | event->lun[3];
344 u8 asc = event->reason & 255;
345 u8 ascq = event->reason >> 8;
346
347 sdev = scsi_device_lookup(shost, 0, target, lun);
348 if (!sdev) {
349 pr_err("SCSI device %d 0 %d %d not found\n",
350 shost->host_no, target, lun);
351 return;
352 }
353
354 /* Handle "Parameters changed", "Mode parameters changed", and
355 "Capacity data has changed". */
356 if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
357 scsi_rescan_device(&sdev->sdev_gendev);
358
359 scsi_device_put(sdev);
360 }
361
362 static void virtscsi_handle_event(struct work_struct *work)
363 {
364 struct virtio_scsi_event_node *event_node =
365 container_of(work, struct virtio_scsi_event_node, work);
366 struct virtio_scsi *vscsi = event_node->vscsi;
367 struct virtio_scsi_event *event = &event_node->event;
368
369 if (event->event & VIRTIO_SCSI_T_EVENTS_MISSED) {
370 event->event &= ~VIRTIO_SCSI_T_EVENTS_MISSED;
371 scsi_scan_host(virtio_scsi_host(vscsi->vdev));
372 }
373
374 switch (event->event) {
375 case VIRTIO_SCSI_T_NO_EVENT:
376 break;
377 case VIRTIO_SCSI_T_TRANSPORT_RESET:
378 virtscsi_handle_transport_reset(vscsi, event);
379 break;
380 case VIRTIO_SCSI_T_PARAM_CHANGE:
381 virtscsi_handle_param_change(vscsi, event);
382 break;
383 default:
384 pr_err("Unsupport virtio scsi event %x\n", event->event);
385 }
386 virtscsi_kick_event(vscsi, event_node);
387 }
388
389 static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
390 {
391 struct virtio_scsi_event_node *event_node = buf;
392
393 queue_work(system_freezable_wq, &event_node->work);
394 }
395
396 static void virtscsi_event_done(struct virtqueue *vq)
397 {
398 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
399 struct virtio_scsi *vscsi = shost_priv(sh);
400
401 virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
402 };
403
404 /**
405 * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue
406 * @vq : the struct virtqueue we're talking about
407 * @cmd : command structure
408 * @req_size : size of the request buffer
409 * @resp_size : size of the response buffer
410 */
411 static int virtscsi_add_cmd(struct virtqueue *vq,
412 struct virtio_scsi_cmd *cmd,
413 size_t req_size, size_t resp_size)
414 {
415 struct scsi_cmnd *sc = cmd->sc;
416 struct scatterlist *sgs[6], req, resp;
417 struct sg_table *out, *in;
418 unsigned out_num = 0, in_num = 0;
419
420 out = in = NULL;
421
422 if (sc && sc->sc_data_direction != DMA_NONE) {
423 if (sc->sc_data_direction != DMA_FROM_DEVICE)
424 out = &scsi_out(sc)->table;
425 if (sc->sc_data_direction != DMA_TO_DEVICE)
426 in = &scsi_in(sc)->table;
427 }
428
429 /* Request header. */
430 sg_init_one(&req, &cmd->req, req_size);
431 sgs[out_num++] = &req;
432
433 /* Data-out buffer. */
434 if (out) {
435 /* Place WRITE protection SGLs before Data OUT payload */
436 if (scsi_prot_sg_count(sc))
437 sgs[out_num++] = scsi_prot_sglist(sc);
438 sgs[out_num++] = out->sgl;
439 }
440
441 /* Response header. */
442 sg_init_one(&resp, &cmd->resp, resp_size);
443 sgs[out_num + in_num++] = &resp;
444
445 /* Data-in buffer */
446 if (in) {
447 /* Place READ protection SGLs before Data IN payload */
448 if (scsi_prot_sg_count(sc))
449 sgs[out_num + in_num++] = scsi_prot_sglist(sc);
450 sgs[out_num + in_num++] = in->sgl;
451 }
452
453 return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
454 }
455
456 static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq,
457 struct virtio_scsi_cmd *cmd,
458 size_t req_size, size_t resp_size)
459 {
460 unsigned long flags;
461 int err;
462 bool needs_kick = false;
463
464 spin_lock_irqsave(&vq->vq_lock, flags);
465 err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
466 if (!err)
467 needs_kick = virtqueue_kick_prepare(vq->vq);
468
469 spin_unlock_irqrestore(&vq->vq_lock, flags);
470
471 if (needs_kick)
472 virtqueue_notify(vq->vq);
473 return err;
474 }
475
476 static void virtio_scsi_init_hdr(struct virtio_scsi_cmd_req *cmd,
477 struct scsi_cmnd *sc)
478 {
479 cmd->lun[0] = 1;
480 cmd->lun[1] = sc->device->id;
481 cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
482 cmd->lun[3] = sc->device->lun & 0xff;
483 cmd->tag = (unsigned long)sc;
484 cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
485 cmd->prio = 0;
486 cmd->crn = 0;
487 }
488
489 static void virtio_scsi_init_hdr_pi(struct virtio_scsi_cmd_req_pi *cmd_pi,
490 struct scsi_cmnd *sc)
491 {
492 struct request *rq = sc->request;
493 struct blk_integrity *bi;
494
495 virtio_scsi_init_hdr((struct virtio_scsi_cmd_req *)cmd_pi, sc);
496
497 if (!rq || !scsi_prot_sg_count(sc))
498 return;
499
500 bi = blk_get_integrity(rq->rq_disk);
501
502 if (sc->sc_data_direction == DMA_TO_DEVICE)
503 cmd_pi->pi_bytesout = blk_rq_sectors(rq) * bi->tuple_size;
504 else if (sc->sc_data_direction == DMA_FROM_DEVICE)
505 cmd_pi->pi_bytesin = blk_rq_sectors(rq) * bi->tuple_size;
506 }
507
508 static int virtscsi_queuecommand(struct virtio_scsi *vscsi,
509 struct virtio_scsi_vq *req_vq,
510 struct scsi_cmnd *sc)
511 {
512 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
513 struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
514 int req_size;
515
516 BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
517
518 /* TODO: check feature bit and fail if unsupported? */
519 BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
520
521 dev_dbg(&sc->device->sdev_gendev,
522 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
523
524 memset(cmd, 0, sizeof(*cmd));
525 cmd->sc = sc;
526
527 BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
528
529 if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) {
530 virtio_scsi_init_hdr_pi(&cmd->req.cmd_pi, sc);
531 memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
532 req_size = sizeof(cmd->req.cmd_pi);
533 } else {
534 virtio_scsi_init_hdr(&cmd->req.cmd, sc);
535 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
536 req_size = sizeof(cmd->req.cmd);
537 }
538
539 if (virtscsi_kick_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd)) != 0)
540 return SCSI_MLQUEUE_HOST_BUSY;
541 return 0;
542 }
543
544 static int virtscsi_queuecommand_single(struct Scsi_Host *sh,
545 struct scsi_cmnd *sc)
546 {
547 struct virtio_scsi *vscsi = shost_priv(sh);
548 struct virtio_scsi_target_state *tgt =
549 scsi_target(sc->device)->hostdata;
550
551 atomic_inc(&tgt->reqs);
552 return virtscsi_queuecommand(vscsi, &vscsi->req_vqs[0], sc);
553 }
554
555 static struct virtio_scsi_vq *virtscsi_pick_vq(struct virtio_scsi *vscsi,
556 struct virtio_scsi_target_state *tgt)
557 {
558 struct virtio_scsi_vq *vq;
559 unsigned long flags;
560 u32 queue_num;
561
562 local_irq_save(flags);
563 if (atomic_inc_return(&tgt->reqs) > 1) {
564 unsigned long seq;
565
566 do {
567 seq = read_seqcount_begin(&tgt->tgt_seq);
568 vq = tgt->req_vq;
569 } while (read_seqcount_retry(&tgt->tgt_seq, seq));
570 } else {
571 /* no writes can be concurrent because of atomic_t */
572 write_seqcount_begin(&tgt->tgt_seq);
573
574 /* keep previous req_vq if a reader just arrived */
575 if (unlikely(atomic_read(&tgt->reqs) > 1)) {
576 vq = tgt->req_vq;
577 goto unlock;
578 }
579
580 queue_num = smp_processor_id();
581 while (unlikely(queue_num >= vscsi->num_queues))
582 queue_num -= vscsi->num_queues;
583 tgt->req_vq = vq = &vscsi->req_vqs[queue_num];
584 unlock:
585 write_seqcount_end(&tgt->tgt_seq);
586 }
587 local_irq_restore(flags);
588
589 return vq;
590 }
591
592 static int virtscsi_queuecommand_multi(struct Scsi_Host *sh,
593 struct scsi_cmnd *sc)
594 {
595 struct virtio_scsi *vscsi = shost_priv(sh);
596 struct virtio_scsi_target_state *tgt =
597 scsi_target(sc->device)->hostdata;
598 struct virtio_scsi_vq *req_vq = virtscsi_pick_vq(vscsi, tgt);
599
600 return virtscsi_queuecommand(vscsi, req_vq, sc);
601 }
602
603 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
604 {
605 DECLARE_COMPLETION_ONSTACK(comp);
606 int ret = FAILED;
607
608 cmd->comp = &comp;
609 if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd,
610 sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0)
611 goto out;
612
613 wait_for_completion(&comp);
614 if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
615 cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
616 ret = SUCCESS;
617
618 /*
619 * The spec guarantees that all requests related to the TMF have
620 * been completed, but the callback might not have run yet if
621 * we're using independent interrupts (e.g. MSI). Poll the
622 * virtqueues once.
623 *
624 * In the abort case, sc->scsi_done will do nothing, because
625 * the block layer must have detected a timeout and as a result
626 * REQ_ATOM_COMPLETE has been set.
627 */
628 virtscsi_poll_requests(vscsi);
629
630 out:
631 mempool_free(cmd, virtscsi_cmd_pool);
632 return ret;
633 }
634
635 static int virtscsi_device_reset(struct scsi_cmnd *sc)
636 {
637 struct virtio_scsi *vscsi = shost_priv(sc->device->host);
638 struct virtio_scsi_cmd *cmd;
639
640 sdev_printk(KERN_INFO, sc->device, "device reset\n");
641 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
642 if (!cmd)
643 return FAILED;
644
645 memset(cmd, 0, sizeof(*cmd));
646 cmd->sc = sc;
647 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
648 .type = VIRTIO_SCSI_T_TMF,
649 .subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET,
650 .lun[0] = 1,
651 .lun[1] = sc->device->id,
652 .lun[2] = (sc->device->lun >> 8) | 0x40,
653 .lun[3] = sc->device->lun & 0xff,
654 };
655 return virtscsi_tmf(vscsi, cmd);
656 }
657
658 /**
659 * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth
660 * @sdev: Virtscsi target whose queue depth to change
661 * @qdepth: New queue depth
662 * @reason: Reason for the queue depth change.
663 */
664 static int virtscsi_change_queue_depth(struct scsi_device *sdev,
665 int qdepth,
666 int reason)
667 {
668 struct Scsi_Host *shost = sdev->host;
669 int max_depth = shost->cmd_per_lun;
670
671 switch (reason) {
672 case SCSI_QDEPTH_QFULL: /* Drop qdepth in response to BUSY state */
673 scsi_track_queue_full(sdev, qdepth);
674 break;
675 case SCSI_QDEPTH_RAMP_UP: /* Raise qdepth after BUSY state resolved */
676 case SCSI_QDEPTH_DEFAULT: /* Manual change via sysfs */
677 scsi_adjust_queue_depth(sdev,
678 scsi_get_tag_type(sdev),
679 min(max_depth, qdepth));
680 break;
681 default:
682 return -EOPNOTSUPP;
683 }
684
685 return sdev->queue_depth;
686 }
687
688 static int virtscsi_abort(struct scsi_cmnd *sc)
689 {
690 struct virtio_scsi *vscsi = shost_priv(sc->device->host);
691 struct virtio_scsi_cmd *cmd;
692
693 scmd_printk(KERN_INFO, sc, "abort\n");
694 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
695 if (!cmd)
696 return FAILED;
697
698 memset(cmd, 0, sizeof(*cmd));
699 cmd->sc = sc;
700 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
701 .type = VIRTIO_SCSI_T_TMF,
702 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
703 .lun[0] = 1,
704 .lun[1] = sc->device->id,
705 .lun[2] = (sc->device->lun >> 8) | 0x40,
706 .lun[3] = sc->device->lun & 0xff,
707 .tag = (unsigned long)sc,
708 };
709 return virtscsi_tmf(vscsi, cmd);
710 }
711
712 static int virtscsi_target_alloc(struct scsi_target *starget)
713 {
714 struct Scsi_Host *sh = dev_to_shost(starget->dev.parent);
715 struct virtio_scsi *vscsi = shost_priv(sh);
716
717 struct virtio_scsi_target_state *tgt =
718 kmalloc(sizeof(*tgt), GFP_KERNEL);
719 if (!tgt)
720 return -ENOMEM;
721
722 seqcount_init(&tgt->tgt_seq);
723 atomic_set(&tgt->reqs, 0);
724 tgt->req_vq = &vscsi->req_vqs[0];
725
726 starget->hostdata = tgt;
727 return 0;
728 }
729
730 static void virtscsi_target_destroy(struct scsi_target *starget)
731 {
732 struct virtio_scsi_target_state *tgt = starget->hostdata;
733 kfree(tgt);
734 }
735
736 static struct scsi_host_template virtscsi_host_template_single = {
737 .module = THIS_MODULE,
738 .name = "Virtio SCSI HBA",
739 .proc_name = "virtio_scsi",
740 .this_id = -1,
741 .cmd_size = sizeof(struct virtio_scsi_cmd),
742 .queuecommand = virtscsi_queuecommand_single,
743 .change_queue_depth = virtscsi_change_queue_depth,
744 .eh_abort_handler = virtscsi_abort,
745 .eh_device_reset_handler = virtscsi_device_reset,
746
747 .can_queue = 1024,
748 .dma_boundary = UINT_MAX,
749 .use_clustering = ENABLE_CLUSTERING,
750 .target_alloc = virtscsi_target_alloc,
751 .target_destroy = virtscsi_target_destroy,
752 };
753
754 static struct scsi_host_template virtscsi_host_template_multi = {
755 .module = THIS_MODULE,
756 .name = "Virtio SCSI HBA",
757 .proc_name = "virtio_scsi",
758 .this_id = -1,
759 .cmd_size = sizeof(struct virtio_scsi_cmd),
760 .queuecommand = virtscsi_queuecommand_multi,
761 .change_queue_depth = virtscsi_change_queue_depth,
762 .eh_abort_handler = virtscsi_abort,
763 .eh_device_reset_handler = virtscsi_device_reset,
764
765 .can_queue = 1024,
766 .dma_boundary = UINT_MAX,
767 .use_clustering = ENABLE_CLUSTERING,
768 .target_alloc = virtscsi_target_alloc,
769 .target_destroy = virtscsi_target_destroy,
770 };
771
772 #define virtscsi_config_get(vdev, fld) \
773 ({ \
774 typeof(((struct virtio_scsi_config *)0)->fld) __val; \
775 virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
776 __val; \
777 })
778
779 #define virtscsi_config_set(vdev, fld, val) \
780 do { \
781 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
782 virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
783 } while(0)
784
785 static void __virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
786 {
787 int i;
788 int cpu;
789
790 /* In multiqueue mode, when the number of cpu is equal
791 * to the number of request queues, we let the qeueues
792 * to be private to one cpu by setting the affinity hint
793 * to eliminate the contention.
794 */
795 if ((vscsi->num_queues == 1 ||
796 vscsi->num_queues != num_online_cpus()) && affinity) {
797 if (vscsi->affinity_hint_set)
798 affinity = false;
799 else
800 return;
801 }
802
803 if (affinity) {
804 i = 0;
805 for_each_online_cpu(cpu) {
806 virtqueue_set_affinity(vscsi->req_vqs[i].vq, cpu);
807 i++;
808 }
809
810 vscsi->affinity_hint_set = true;
811 } else {
812 for (i = 0; i < vscsi->num_queues; i++) {
813 if (!vscsi->req_vqs[i].vq)
814 continue;
815
816 virtqueue_set_affinity(vscsi->req_vqs[i].vq, -1);
817 }
818
819 vscsi->affinity_hint_set = false;
820 }
821 }
822
823 static void virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
824 {
825 get_online_cpus();
826 __virtscsi_set_affinity(vscsi, affinity);
827 put_online_cpus();
828 }
829
830 static int virtscsi_cpu_callback(struct notifier_block *nfb,
831 unsigned long action, void *hcpu)
832 {
833 struct virtio_scsi *vscsi = container_of(nfb, struct virtio_scsi, nb);
834 switch(action) {
835 case CPU_ONLINE:
836 case CPU_ONLINE_FROZEN:
837 case CPU_DEAD:
838 case CPU_DEAD_FROZEN:
839 __virtscsi_set_affinity(vscsi, true);
840 break;
841 default:
842 break;
843 }
844 return NOTIFY_OK;
845 }
846
847 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
848 struct virtqueue *vq)
849 {
850 spin_lock_init(&virtscsi_vq->vq_lock);
851 virtscsi_vq->vq = vq;
852 }
853
854 static void virtscsi_scan(struct virtio_device *vdev)
855 {
856 struct Scsi_Host *shost = virtio_scsi_host(vdev);
857 struct virtio_scsi *vscsi = shost_priv(shost);
858
859 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
860 virtscsi_kick_event_all(vscsi);
861
862 scsi_scan_host(shost);
863 }
864
865 static void virtscsi_remove_vqs(struct virtio_device *vdev)
866 {
867 struct Scsi_Host *sh = virtio_scsi_host(vdev);
868 struct virtio_scsi *vscsi = shost_priv(sh);
869
870 virtscsi_set_affinity(vscsi, false);
871
872 /* Stop all the virtqueues. */
873 vdev->config->reset(vdev);
874
875 vdev->config->del_vqs(vdev);
876 }
877
878 static int virtscsi_init(struct virtio_device *vdev,
879 struct virtio_scsi *vscsi)
880 {
881 int err;
882 u32 i;
883 u32 num_vqs;
884 vq_callback_t **callbacks;
885 const char **names;
886 struct virtqueue **vqs;
887
888 num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
889 vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL);
890 callbacks = kmalloc(num_vqs * sizeof(vq_callback_t *), GFP_KERNEL);
891 names = kmalloc(num_vqs * sizeof(char *), GFP_KERNEL);
892
893 if (!callbacks || !vqs || !names) {
894 err = -ENOMEM;
895 goto out;
896 }
897
898 callbacks[0] = virtscsi_ctrl_done;
899 callbacks[1] = virtscsi_event_done;
900 names[0] = "control";
901 names[1] = "event";
902 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
903 callbacks[i] = virtscsi_req_done;
904 names[i] = "request";
905 }
906
907 /* Discover virtqueues and write information to configuration. */
908 err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
909 if (err)
910 goto out;
911
912 virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
913 virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
914 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
915 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
916 vqs[i]);
917
918 virtscsi_set_affinity(vscsi, true);
919
920 virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
921 virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
922
923 err = 0;
924
925 out:
926 kfree(names);
927 kfree(callbacks);
928 kfree(vqs);
929 if (err)
930 virtscsi_remove_vqs(vdev);
931 return err;
932 }
933
934 static int virtscsi_probe(struct virtio_device *vdev)
935 {
936 struct Scsi_Host *shost;
937 struct virtio_scsi *vscsi;
938 int err, host_prot;
939 u32 sg_elems, num_targets;
940 u32 cmd_per_lun;
941 u32 num_queues;
942 struct scsi_host_template *hostt;
943
944 /* We need to know how many queues before we allocate. */
945 num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
946
947 num_targets = virtscsi_config_get(vdev, max_target) + 1;
948
949 if (num_queues == 1)
950 hostt = &virtscsi_host_template_single;
951 else
952 hostt = &virtscsi_host_template_multi;
953
954 shost = scsi_host_alloc(hostt,
955 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues);
956 if (!shost)
957 return -ENOMEM;
958
959 sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
960 shost->sg_tablesize = sg_elems;
961 vscsi = shost_priv(shost);
962 vscsi->vdev = vdev;
963 vscsi->num_queues = num_queues;
964 vdev->priv = shost;
965
966 err = virtscsi_init(vdev, vscsi);
967 if (err)
968 goto virtscsi_init_failed;
969
970 vscsi->nb.notifier_call = &virtscsi_cpu_callback;
971 err = register_hotcpu_notifier(&vscsi->nb);
972 if (err) {
973 pr_err("registering cpu notifier failed\n");
974 goto scsi_add_host_failed;
975 }
976
977 cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
978 shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
979 shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
980
981 /* LUNs > 256 are reported with format 1, so they go in the range
982 * 16640-32767.
983 */
984 shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
985 shost->max_id = num_targets;
986 shost->max_channel = 0;
987 shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
988
989 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
990 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
991 SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
992 SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
993
994 scsi_host_set_prot(shost, host_prot);
995 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
996 }
997
998 err = scsi_add_host(shost, &vdev->dev);
999 if (err)
1000 goto scsi_add_host_failed;
1001 /*
1002 * scsi_scan_host() happens in virtscsi_scan() via virtio_driver->scan()
1003 * after VIRTIO_CONFIG_S_DRIVER_OK has been set..
1004 */
1005 return 0;
1006
1007 scsi_add_host_failed:
1008 vdev->config->del_vqs(vdev);
1009 virtscsi_init_failed:
1010 scsi_host_put(shost);
1011 return err;
1012 }
1013
1014 static void virtscsi_remove(struct virtio_device *vdev)
1015 {
1016 struct Scsi_Host *shost = virtio_scsi_host(vdev);
1017 struct virtio_scsi *vscsi = shost_priv(shost);
1018
1019 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
1020 virtscsi_cancel_event_work(vscsi);
1021
1022 scsi_remove_host(shost);
1023
1024 unregister_hotcpu_notifier(&vscsi->nb);
1025
1026 virtscsi_remove_vqs(vdev);
1027 scsi_host_put(shost);
1028 }
1029
1030 #ifdef CONFIG_PM_SLEEP
1031 static int virtscsi_freeze(struct virtio_device *vdev)
1032 {
1033 struct Scsi_Host *sh = virtio_scsi_host(vdev);
1034 struct virtio_scsi *vscsi = shost_priv(sh);
1035
1036 unregister_hotcpu_notifier(&vscsi->nb);
1037 virtscsi_remove_vqs(vdev);
1038 return 0;
1039 }
1040
1041 static int virtscsi_restore(struct virtio_device *vdev)
1042 {
1043 struct Scsi_Host *sh = virtio_scsi_host(vdev);
1044 struct virtio_scsi *vscsi = shost_priv(sh);
1045 int err;
1046
1047 err = virtscsi_init(vdev, vscsi);
1048 if (err)
1049 return err;
1050
1051 err = register_hotcpu_notifier(&vscsi->nb);
1052 if (err) {
1053 vdev->config->del_vqs(vdev);
1054 return err;
1055 }
1056
1057 virtio_device_ready(vdev);
1058
1059 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
1060 virtscsi_kick_event_all(vscsi);
1061
1062 return err;
1063 }
1064 #endif
1065
1066 static struct virtio_device_id id_table[] = {
1067 { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
1068 { 0 },
1069 };
1070
1071 static unsigned int features[] = {
1072 VIRTIO_SCSI_F_HOTPLUG,
1073 VIRTIO_SCSI_F_CHANGE,
1074 VIRTIO_SCSI_F_T10_PI,
1075 };
1076
1077 static struct virtio_driver virtio_scsi_driver = {
1078 .feature_table = features,
1079 .feature_table_size = ARRAY_SIZE(features),
1080 .driver.name = KBUILD_MODNAME,
1081 .driver.owner = THIS_MODULE,
1082 .id_table = id_table,
1083 .probe = virtscsi_probe,
1084 .scan = virtscsi_scan,
1085 #ifdef CONFIG_PM_SLEEP
1086 .freeze = virtscsi_freeze,
1087 .restore = virtscsi_restore,
1088 #endif
1089 .remove = virtscsi_remove,
1090 };
1091
1092 static int __init init(void)
1093 {
1094 int ret = -ENOMEM;
1095
1096 virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
1097 if (!virtscsi_cmd_cache) {
1098 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
1099 goto error;
1100 }
1101
1102
1103 virtscsi_cmd_pool =
1104 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
1105 virtscsi_cmd_cache);
1106 if (!virtscsi_cmd_pool) {
1107 pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
1108 goto error;
1109 }
1110 ret = register_virtio_driver(&virtio_scsi_driver);
1111 if (ret < 0)
1112 goto error;
1113
1114 return 0;
1115
1116 error:
1117 if (virtscsi_cmd_pool) {
1118 mempool_destroy(virtscsi_cmd_pool);
1119 virtscsi_cmd_pool = NULL;
1120 }
1121 if (virtscsi_cmd_cache) {
1122 kmem_cache_destroy(virtscsi_cmd_cache);
1123 virtscsi_cmd_cache = NULL;
1124 }
1125 return ret;
1126 }
1127
1128 static void __exit fini(void)
1129 {
1130 unregister_virtio_driver(&virtio_scsi_driver);
1131 mempool_destroy(virtscsi_cmd_pool);
1132 kmem_cache_destroy(virtscsi_cmd_cache);
1133 }
1134 module_init(init);
1135 module_exit(fini);
1136
1137 MODULE_DEVICE_TABLE(virtio, id_table);
1138 MODULE_DESCRIPTION("Virtio SCSI HBA driver");
1139 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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