Version:  2.0.40 2.2.26 2.4.37 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17

Linux/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         schedule_work(&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 = (struct Scsi_Host *)vdev->priv;
857 
858         scsi_scan_host(shost);
859 }
860 
861 static void virtscsi_remove_vqs(struct virtio_device *vdev)
862 {
863         struct Scsi_Host *sh = virtio_scsi_host(vdev);
864         struct virtio_scsi *vscsi = shost_priv(sh);
865 
866         virtscsi_set_affinity(vscsi, false);
867 
868         /* Stop all the virtqueues. */
869         vdev->config->reset(vdev);
870 
871         vdev->config->del_vqs(vdev);
872 }
873 
874 static int virtscsi_init(struct virtio_device *vdev,
875                          struct virtio_scsi *vscsi)
876 {
877         int err;
878         u32 i;
879         u32 num_vqs;
880         vq_callback_t **callbacks;
881         const char **names;
882         struct virtqueue **vqs;
883 
884         num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
885         vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL);
886         callbacks = kmalloc(num_vqs * sizeof(vq_callback_t *), GFP_KERNEL);
887         names = kmalloc(num_vqs * sizeof(char *), GFP_KERNEL);
888 
889         if (!callbacks || !vqs || !names) {
890                 err = -ENOMEM;
891                 goto out;
892         }
893 
894         callbacks[0] = virtscsi_ctrl_done;
895         callbacks[1] = virtscsi_event_done;
896         names[0] = "control";
897         names[1] = "event";
898         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
899                 callbacks[i] = virtscsi_req_done;
900                 names[i] = "request";
901         }
902 
903         /* Discover virtqueues and write information to configuration.  */
904         err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
905         if (err)
906                 goto out;
907 
908         virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
909         virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
910         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
911                 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
912                                  vqs[i]);
913 
914         virtscsi_set_affinity(vscsi, true);
915 
916         virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
917         virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
918 
919         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
920                 virtscsi_kick_event_all(vscsi);
921 
922         err = 0;
923 
924 out:
925         kfree(names);
926         kfree(callbacks);
927         kfree(vqs);
928         if (err)
929                 virtscsi_remove_vqs(vdev);
930         return err;
931 }
932 
933 static int virtscsi_probe(struct virtio_device *vdev)
934 {
935         struct Scsi_Host *shost;
936         struct virtio_scsi *vscsi;
937         int err, host_prot;
938         u32 sg_elems, num_targets;
939         u32 cmd_per_lun;
940         u32 num_queues;
941         struct scsi_host_template *hostt;
942 
943         /* We need to know how many queues before we allocate. */
944         num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
945 
946         num_targets = virtscsi_config_get(vdev, max_target) + 1;
947 
948         if (num_queues == 1)
949                 hostt = &virtscsi_host_template_single;
950         else
951                 hostt = &virtscsi_host_template_multi;
952 
953         shost = scsi_host_alloc(hostt,
954                 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues);
955         if (!shost)
956                 return -ENOMEM;
957 
958         sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
959         shost->sg_tablesize = sg_elems;
960         vscsi = shost_priv(shost);
961         vscsi->vdev = vdev;
962         vscsi->num_queues = num_queues;
963         vdev->priv = shost;
964 
965         err = virtscsi_init(vdev, vscsi);
966         if (err)
967                 goto virtscsi_init_failed;
968 
969         vscsi->nb.notifier_call = &virtscsi_cpu_callback;
970         err = register_hotcpu_notifier(&vscsi->nb);
971         if (err) {
972                 pr_err("registering cpu notifier failed\n");
973                 goto scsi_add_host_failed;
974         }
975 
976         cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
977         shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
978         shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
979 
980         /* LUNs > 256 are reported with format 1, so they go in the range
981          * 16640-32767.
982          */
983         shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
984         shost->max_id = num_targets;
985         shost->max_channel = 0;
986         shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
987 
988         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
989                 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
990                             SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
991                             SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
992 
993                 scsi_host_set_prot(shost, host_prot);
994                 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
995         }
996 
997         err = scsi_add_host(shost, &vdev->dev);
998         if (err)
999                 goto scsi_add_host_failed;
1000         /*
1001          * scsi_scan_host() happens in virtscsi_scan() via virtio_driver->scan()
1002          * after VIRTIO_CONFIG_S_DRIVER_OK has been set..
1003          */
1004         return 0;
1005 
1006 scsi_add_host_failed:
1007         vdev->config->del_vqs(vdev);
1008 virtscsi_init_failed:
1009         scsi_host_put(shost);
1010         return err;
1011 }
1012 
1013 static void virtscsi_remove(struct virtio_device *vdev)
1014 {
1015         struct Scsi_Host *shost = virtio_scsi_host(vdev);
1016         struct virtio_scsi *vscsi = shost_priv(shost);
1017 
1018         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
1019                 virtscsi_cancel_event_work(vscsi);
1020 
1021         scsi_remove_host(shost);
1022 
1023         unregister_hotcpu_notifier(&vscsi->nb);
1024 
1025         virtscsi_remove_vqs(vdev);
1026         scsi_host_put(shost);
1027 }
1028 
1029 #ifdef CONFIG_PM_SLEEP
1030 static int virtscsi_freeze(struct virtio_device *vdev)
1031 {
1032         struct Scsi_Host *sh = virtio_scsi_host(vdev);
1033         struct virtio_scsi *vscsi = shost_priv(sh);
1034 
1035         unregister_hotcpu_notifier(&vscsi->nb);
1036         virtscsi_remove_vqs(vdev);
1037         return 0;
1038 }
1039 
1040 static int virtscsi_restore(struct virtio_device *vdev)
1041 {
1042         struct Scsi_Host *sh = virtio_scsi_host(vdev);
1043         struct virtio_scsi *vscsi = shost_priv(sh);
1044         int err;
1045 
1046         err = virtscsi_init(vdev, vscsi);
1047         if (err)
1048                 return err;
1049 
1050         err = register_hotcpu_notifier(&vscsi->nb);
1051         if (err)
1052                 vdev->config->del_vqs(vdev);
1053 
1054         return err;
1055 }
1056 #endif
1057 
1058 static struct virtio_device_id id_table[] = {
1059         { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
1060         { 0 },
1061 };
1062 
1063 static unsigned int features[] = {
1064         VIRTIO_SCSI_F_HOTPLUG,
1065         VIRTIO_SCSI_F_CHANGE,
1066         VIRTIO_SCSI_F_T10_PI,
1067 };
1068 
1069 static struct virtio_driver virtio_scsi_driver = {
1070         .feature_table = features,
1071         .feature_table_size = ARRAY_SIZE(features),
1072         .driver.name = KBUILD_MODNAME,
1073         .driver.owner = THIS_MODULE,
1074         .id_table = id_table,
1075         .probe = virtscsi_probe,
1076         .scan = virtscsi_scan,
1077 #ifdef CONFIG_PM_SLEEP
1078         .freeze = virtscsi_freeze,
1079         .restore = virtscsi_restore,
1080 #endif
1081         .remove = virtscsi_remove,
1082 };
1083 
1084 static int __init init(void)
1085 {
1086         int ret = -ENOMEM;
1087 
1088         virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
1089         if (!virtscsi_cmd_cache) {
1090                 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
1091                 goto error;
1092         }
1093 
1094 
1095         virtscsi_cmd_pool =
1096                 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
1097                                          virtscsi_cmd_cache);
1098         if (!virtscsi_cmd_pool) {
1099                 pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
1100                 goto error;
1101         }
1102         ret = register_virtio_driver(&virtio_scsi_driver);
1103         if (ret < 0)
1104                 goto error;
1105 
1106         return 0;
1107 
1108 error:
1109         if (virtscsi_cmd_pool) {
1110                 mempool_destroy(virtscsi_cmd_pool);
1111                 virtscsi_cmd_pool = NULL;
1112         }
1113         if (virtscsi_cmd_cache) {
1114                 kmem_cache_destroy(virtscsi_cmd_cache);
1115                 virtscsi_cmd_cache = NULL;
1116         }
1117         return ret;
1118 }
1119 
1120 static void __exit fini(void)
1121 {
1122         unregister_virtio_driver(&virtio_scsi_driver);
1123         mempool_destroy(virtscsi_cmd_pool);
1124         kmem_cache_destroy(virtscsi_cmd_cache);
1125 }
1126 module_init(init);
1127 module_exit(fini);
1128 
1129 MODULE_DEVICE_TABLE(virtio, id_table);
1130 MODULE_DESCRIPTION("Virtio SCSI HBA driver");
1131 MODULE_LICENSE("GPL");
1132 

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