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1/*
2 * Virtio SCSI HBA driver
3 *
4 * Copyright IBM Corp. 2010
5 * Copyright Red Hat, Inc. 2011
6 *
7 * Authors:
8 * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
9 * Paolo Bonzini <pbonzini@redhat.com>
10 *
11 * This work is licensed under the terms of the GNU GPL, version 2 or later.
12 * See the COPYING file in the top-level directory.
13 *
14 */
15
16#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 */
35struct 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
51struct virtio_scsi_event_node {
52 struct virtio_scsi *vscsi;
53 struct virtio_scsi_event event;
54 struct work_struct work;
55};
56
57struct 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 */
90struct 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 */
102struct 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
121static struct kmem_cache *virtscsi_cmd_cache;
122static mempool_t *virtscsi_cmd_pool;
123
124static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
125{
126 return vdev->priv;
127}
128
129static 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 */
148static 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
213static 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
234static 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
276static 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
286static 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
294static 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
315static 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
327static 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
335static 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
362static 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
387static 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
414static 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
422static 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 */
438static 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
475static 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
495static 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
539out:
540 return ret;
541}
542
543static 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
554static 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
581static 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
592static 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
608out:
609 mempool_free(cmd, virtscsi_cmd_pool);
610 return ret;
611}
612
613static 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
636static 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
660static 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
675static void virtscsi_target_destroy(struct scsi_target *starget)
676{
677 struct virtio_scsi_target_state *tgt = starget->hostdata;
678 kfree(tgt);
679}
680
681static 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
697static 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
726static 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
764static 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
771static 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
788static 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
795static 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
802static 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
815static 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
865out:
866 kfree(names);
867 kfree(callbacks);
868 kfree(vqs);
869 if (err)
870 virtscsi_remove_vqs(vdev);
871 return err;
872}
873
874static 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
937scsi_add_host_failed:
938 vdev->config->del_vqs(vdev);
939virtscsi_init_failed:
940 scsi_host_put(shost);
941 return err;
942}
943
944static 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
961static 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
971static 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
989static struct virtio_device_id id_table[] = {
990 { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
991 { 0 },
992};
993
994static unsigned int features[] = {
995 VIRTIO_SCSI_F_HOTPLUG,
996 VIRTIO_SCSI_F_CHANGE,
997};
998
999static 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
1014static 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
1038error:
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
1050static 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}
1056module_init(init);
1057module_exit(fini);
1058
1059MODULE_DEVICE_TABLE(virtio, id_table);
1060MODULE_DESCRIPTION("Virtio SCSI HBA driver");
1061MODULE_LICENSE("GPL");