Version:  2.0.40 2.2.26 2.4.37 3.0 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

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 
 31 #define VIRTIO_SCSI_MEMPOOL_SZ 64
 32 #define VIRTIO_SCSI_EVENT_LEN 8
 33 #define VIRTIO_SCSI_VQ_BASE 2
 34 
 35 /* Command queue element */
 36 struct virtio_scsi_cmd {
 37         struct scsi_cmnd *sc;
 38         struct completion *comp;
 39         union {
 40                 struct virtio_scsi_cmd_req       cmd;
 41                 struct virtio_scsi_cmd_req_pi    cmd_pi;
 42                 struct virtio_scsi_ctrl_tmf_req  tmf;
 43                 struct virtio_scsi_ctrl_an_req   an;
 44         } req;
 45         union {
 46                 struct virtio_scsi_cmd_resp      cmd;
 47                 struct virtio_scsi_ctrl_tmf_resp tmf;
 48                 struct virtio_scsi_ctrl_an_resp  an;
 49                 struct virtio_scsi_event         evt;
 50         } resp;
 51 } ____cacheline_aligned_in_smp;
 52 
 53 struct virtio_scsi_event_node {
 54         struct virtio_scsi *vscsi;
 55         struct virtio_scsi_event event;
 56         struct work_struct work;
 57 };
 58 
 59 struct virtio_scsi_vq {
 60         /* Protects vq */
 61         spinlock_t vq_lock;
 62 
 63         struct virtqueue *vq;
 64 };
 65 
 66 /*
 67  * Per-target queue state.
 68  *
 69  * This struct holds the data needed by the queue steering policy.  When a
 70  * target is sent multiple requests, we need to drive them to the same queue so
 71  * that FIFO processing order is kept.  However, if a target was idle, we can
 72  * choose a queue arbitrarily.  In this case the queue is chosen according to
 73  * the current VCPU, so the driver expects the number of request queues to be
 74  * equal to the number of VCPUs.  This makes it easy and fast to select the
 75  * queue, and also lets the driver optimize the IRQ affinity for the virtqueues
 76  * (each virtqueue's affinity is set to the CPU that "owns" the queue).
 77  *
 78  * tgt_lock is held to serialize reading and writing req_vq. Reading req_vq
 79  * could be done locklessly, but we do not do it yet.
 80  *
 81  * Decrements of reqs are never concurrent with writes of req_vq: before the
 82  * decrement reqs will be != 0; after the decrement the virtqueue completion
 83  * routine will not use the req_vq so it can be changed by a new request.
 84  * Thus they can happen outside the tgt_lock, provided of course we make reqs
 85  * an atomic_t.
 86  */
 87 struct virtio_scsi_target_state {
 88         /* This spinlock never held at the same time as vq_lock. */
 89         spinlock_t tgt_lock;
 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         spin_lock_irqsave(&tgt->tgt_lock, flags);
563 
564         if (atomic_inc_return(&tgt->reqs) > 1)
565                 vq = tgt->req_vq;
566         else {
567                 queue_num = smp_processor_id();
568                 while (unlikely(queue_num >= vscsi->num_queues))
569                         queue_num -= vscsi->num_queues;
570 
571                 tgt->req_vq = vq = &vscsi->req_vqs[queue_num];
572         }
573 
574         spin_unlock_irqrestore(&tgt->tgt_lock, flags);
575         return vq;
576 }
577 
578 static int virtscsi_queuecommand_multi(struct Scsi_Host *sh,
579                                        struct scsi_cmnd *sc)
580 {
581         struct virtio_scsi *vscsi = shost_priv(sh);
582         struct virtio_scsi_target_state *tgt =
583                                 scsi_target(sc->device)->hostdata;
584         struct virtio_scsi_vq *req_vq = virtscsi_pick_vq(vscsi, tgt);
585 
586         return virtscsi_queuecommand(vscsi, req_vq, sc);
587 }
588 
589 static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
590 {
591         DECLARE_COMPLETION_ONSTACK(comp);
592         int ret = FAILED;
593 
594         cmd->comp = &comp;
595         if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd,
596                               sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0)
597                 goto out;
598 
599         wait_for_completion(&comp);
600         if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
601             cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
602                 ret = SUCCESS;
603 
604         /*
605          * The spec guarantees that all requests related to the TMF have
606          * been completed, but the callback might not have run yet if
607          * we're using independent interrupts (e.g. MSI).  Poll the
608          * virtqueues once.
609          *
610          * In the abort case, sc->scsi_done will do nothing, because
611          * the block layer must have detected a timeout and as a result
612          * REQ_ATOM_COMPLETE has been set.
613          */
614         virtscsi_poll_requests(vscsi);
615 
616 out:
617         mempool_free(cmd, virtscsi_cmd_pool);
618         return ret;
619 }
620 
621 static int virtscsi_device_reset(struct scsi_cmnd *sc)
622 {
623         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
624         struct virtio_scsi_cmd *cmd;
625 
626         sdev_printk(KERN_INFO, sc->device, "device reset\n");
627         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
628         if (!cmd)
629                 return FAILED;
630 
631         memset(cmd, 0, sizeof(*cmd));
632         cmd->sc = sc;
633         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
634                 .type = VIRTIO_SCSI_T_TMF,
635                 .subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET,
636                 .lun[0] = 1,
637                 .lun[1] = sc->device->id,
638                 .lun[2] = (sc->device->lun >> 8) | 0x40,
639                 .lun[3] = sc->device->lun & 0xff,
640         };
641         return virtscsi_tmf(vscsi, cmd);
642 }
643 
644 static int virtscsi_abort(struct scsi_cmnd *sc)
645 {
646         struct virtio_scsi *vscsi = shost_priv(sc->device->host);
647         struct virtio_scsi_cmd *cmd;
648 
649         scmd_printk(KERN_INFO, sc, "abort\n");
650         cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
651         if (!cmd)
652                 return FAILED;
653 
654         memset(cmd, 0, sizeof(*cmd));
655         cmd->sc = sc;
656         cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
657                 .type = VIRTIO_SCSI_T_TMF,
658                 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
659                 .lun[0] = 1,
660                 .lun[1] = sc->device->id,
661                 .lun[2] = (sc->device->lun >> 8) | 0x40,
662                 .lun[3] = sc->device->lun & 0xff,
663                 .tag = (unsigned long)sc,
664         };
665         return virtscsi_tmf(vscsi, cmd);
666 }
667 
668 static int virtscsi_target_alloc(struct scsi_target *starget)
669 {
670         struct virtio_scsi_target_state *tgt =
671                                 kmalloc(sizeof(*tgt), GFP_KERNEL);
672         if (!tgt)
673                 return -ENOMEM;
674 
675         spin_lock_init(&tgt->tgt_lock);
676         atomic_set(&tgt->reqs, 0);
677         tgt->req_vq = NULL;
678 
679         starget->hostdata = tgt;
680         return 0;
681 }
682 
683 static void virtscsi_target_destroy(struct scsi_target *starget)
684 {
685         struct virtio_scsi_target_state *tgt = starget->hostdata;
686         kfree(tgt);
687 }
688 
689 static struct scsi_host_template virtscsi_host_template_single = {
690         .module = THIS_MODULE,
691         .name = "Virtio SCSI HBA",
692         .proc_name = "virtio_scsi",
693         .this_id = -1,
694         .cmd_size = sizeof(struct virtio_scsi_cmd),
695         .queuecommand = virtscsi_queuecommand_single,
696         .eh_abort_handler = virtscsi_abort,
697         .eh_device_reset_handler = virtscsi_device_reset,
698 
699         .can_queue = 1024,
700         .dma_boundary = UINT_MAX,
701         .use_clustering = ENABLE_CLUSTERING,
702         .target_alloc = virtscsi_target_alloc,
703         .target_destroy = virtscsi_target_destroy,
704 };
705 
706 static struct scsi_host_template virtscsi_host_template_multi = {
707         .module = THIS_MODULE,
708         .name = "Virtio SCSI HBA",
709         .proc_name = "virtio_scsi",
710         .this_id = -1,
711         .cmd_size = sizeof(struct virtio_scsi_cmd),
712         .queuecommand = virtscsi_queuecommand_multi,
713         .eh_abort_handler = virtscsi_abort,
714         .eh_device_reset_handler = virtscsi_device_reset,
715 
716         .can_queue = 1024,
717         .dma_boundary = UINT_MAX,
718         .use_clustering = ENABLE_CLUSTERING,
719         .target_alloc = virtscsi_target_alloc,
720         .target_destroy = virtscsi_target_destroy,
721 };
722 
723 #define virtscsi_config_get(vdev, fld) \
724         ({ \
725                 typeof(((struct virtio_scsi_config *)0)->fld) __val; \
726                 virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
727                 __val; \
728         })
729 
730 #define virtscsi_config_set(vdev, fld, val) \
731         do { \
732                 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
733                 virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
734         } while(0)
735 
736 static void __virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
737 {
738         int i;
739         int cpu;
740 
741         /* In multiqueue mode, when the number of cpu is equal
742          * to the number of request queues, we let the qeueues
743          * to be private to one cpu by setting the affinity hint
744          * to eliminate the contention.
745          */
746         if ((vscsi->num_queues == 1 ||
747              vscsi->num_queues != num_online_cpus()) && affinity) {
748                 if (vscsi->affinity_hint_set)
749                         affinity = false;
750                 else
751                         return;
752         }
753 
754         if (affinity) {
755                 i = 0;
756                 for_each_online_cpu(cpu) {
757                         virtqueue_set_affinity(vscsi->req_vqs[i].vq, cpu);
758                         i++;
759                 }
760 
761                 vscsi->affinity_hint_set = true;
762         } else {
763                 for (i = 0; i < vscsi->num_queues; i++) {
764                         if (!vscsi->req_vqs[i].vq)
765                                 continue;
766 
767                         virtqueue_set_affinity(vscsi->req_vqs[i].vq, -1);
768                 }
769 
770                 vscsi->affinity_hint_set = false;
771         }
772 }
773 
774 static void virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
775 {
776         get_online_cpus();
777         __virtscsi_set_affinity(vscsi, affinity);
778         put_online_cpus();
779 }
780 
781 static int virtscsi_cpu_callback(struct notifier_block *nfb,
782                                  unsigned long action, void *hcpu)
783 {
784         struct virtio_scsi *vscsi = container_of(nfb, struct virtio_scsi, nb);
785         switch(action) {
786         case CPU_ONLINE:
787         case CPU_ONLINE_FROZEN:
788         case CPU_DEAD:
789         case CPU_DEAD_FROZEN:
790                 __virtscsi_set_affinity(vscsi, true);
791                 break;
792         default:
793                 break;
794         }
795         return NOTIFY_OK;
796 }
797 
798 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
799                              struct virtqueue *vq)
800 {
801         spin_lock_init(&virtscsi_vq->vq_lock);
802         virtscsi_vq->vq = vq;
803 }
804 
805 static void virtscsi_scan(struct virtio_device *vdev)
806 {
807         struct Scsi_Host *shost = (struct Scsi_Host *)vdev->priv;
808 
809         scsi_scan_host(shost);
810 }
811 
812 static void virtscsi_remove_vqs(struct virtio_device *vdev)
813 {
814         struct Scsi_Host *sh = virtio_scsi_host(vdev);
815         struct virtio_scsi *vscsi = shost_priv(sh);
816 
817         virtscsi_set_affinity(vscsi, false);
818 
819         /* Stop all the virtqueues. */
820         vdev->config->reset(vdev);
821 
822         vdev->config->del_vqs(vdev);
823 }
824 
825 static int virtscsi_init(struct virtio_device *vdev,
826                          struct virtio_scsi *vscsi)
827 {
828         int err;
829         u32 i;
830         u32 num_vqs;
831         vq_callback_t **callbacks;
832         const char **names;
833         struct virtqueue **vqs;
834 
835         num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
836         vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL);
837         callbacks = kmalloc(num_vqs * sizeof(vq_callback_t *), GFP_KERNEL);
838         names = kmalloc(num_vqs * sizeof(char *), GFP_KERNEL);
839 
840         if (!callbacks || !vqs || !names) {
841                 err = -ENOMEM;
842                 goto out;
843         }
844 
845         callbacks[0] = virtscsi_ctrl_done;
846         callbacks[1] = virtscsi_event_done;
847         names[0] = "control";
848         names[1] = "event";
849         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
850                 callbacks[i] = virtscsi_req_done;
851                 names[i] = "request";
852         }
853 
854         /* Discover virtqueues and write information to configuration.  */
855         err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
856         if (err)
857                 goto out;
858 
859         virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
860         virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
861         for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
862                 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
863                                  vqs[i]);
864 
865         virtscsi_set_affinity(vscsi, true);
866 
867         virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
868         virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
869 
870         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
871                 virtscsi_kick_event_all(vscsi);
872 
873         err = 0;
874 
875 out:
876         kfree(names);
877         kfree(callbacks);
878         kfree(vqs);
879         if (err)
880                 virtscsi_remove_vqs(vdev);
881         return err;
882 }
883 
884 static int virtscsi_probe(struct virtio_device *vdev)
885 {
886         struct Scsi_Host *shost;
887         struct virtio_scsi *vscsi;
888         int err, host_prot;
889         u32 sg_elems, num_targets;
890         u32 cmd_per_lun;
891         u32 num_queues;
892         struct scsi_host_template *hostt;
893 
894         /* We need to know how many queues before we allocate. */
895         num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
896 
897         num_targets = virtscsi_config_get(vdev, max_target) + 1;
898 
899         if (num_queues == 1)
900                 hostt = &virtscsi_host_template_single;
901         else
902                 hostt = &virtscsi_host_template_multi;
903 
904         shost = scsi_host_alloc(hostt,
905                 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues);
906         if (!shost)
907                 return -ENOMEM;
908 
909         sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
910         shost->sg_tablesize = sg_elems;
911         vscsi = shost_priv(shost);
912         vscsi->vdev = vdev;
913         vscsi->num_queues = num_queues;
914         vdev->priv = shost;
915 
916         err = virtscsi_init(vdev, vscsi);
917         if (err)
918                 goto virtscsi_init_failed;
919 
920         vscsi->nb.notifier_call = &virtscsi_cpu_callback;
921         err = register_hotcpu_notifier(&vscsi->nb);
922         if (err) {
923                 pr_err("registering cpu notifier failed\n");
924                 goto scsi_add_host_failed;
925         }
926 
927         cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
928         shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
929         shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
930 
931         /* LUNs > 256 are reported with format 1, so they go in the range
932          * 16640-32767.
933          */
934         shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
935         shost->max_id = num_targets;
936         shost->max_channel = 0;
937         shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
938 
939         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
940                 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
941                             SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
942                             SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
943 
944                 scsi_host_set_prot(shost, host_prot);
945                 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
946         }
947 
948         err = scsi_add_host(shost, &vdev->dev);
949         if (err)
950                 goto scsi_add_host_failed;
951         /*
952          * scsi_scan_host() happens in virtscsi_scan() via virtio_driver->scan()
953          * after VIRTIO_CONFIG_S_DRIVER_OK has been set..
954          */
955         return 0;
956 
957 scsi_add_host_failed:
958         vdev->config->del_vqs(vdev);
959 virtscsi_init_failed:
960         scsi_host_put(shost);
961         return err;
962 }
963 
964 static void virtscsi_remove(struct virtio_device *vdev)
965 {
966         struct Scsi_Host *shost = virtio_scsi_host(vdev);
967         struct virtio_scsi *vscsi = shost_priv(shost);
968 
969         if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
970                 virtscsi_cancel_event_work(vscsi);
971 
972         scsi_remove_host(shost);
973 
974         unregister_hotcpu_notifier(&vscsi->nb);
975 
976         virtscsi_remove_vqs(vdev);
977         scsi_host_put(shost);
978 }
979 
980 #ifdef CONFIG_PM_SLEEP
981 static int virtscsi_freeze(struct virtio_device *vdev)
982 {
983         struct Scsi_Host *sh = virtio_scsi_host(vdev);
984         struct virtio_scsi *vscsi = shost_priv(sh);
985 
986         unregister_hotcpu_notifier(&vscsi->nb);
987         virtscsi_remove_vqs(vdev);
988         return 0;
989 }
990 
991 static int virtscsi_restore(struct virtio_device *vdev)
992 {
993         struct Scsi_Host *sh = virtio_scsi_host(vdev);
994         struct virtio_scsi *vscsi = shost_priv(sh);
995         int err;
996 
997         err = virtscsi_init(vdev, vscsi);
998         if (err)
999                 return err;
1000 
1001         err = register_hotcpu_notifier(&vscsi->nb);
1002         if (err)
1003                 vdev->config->del_vqs(vdev);
1004 
1005         return err;
1006 }
1007 #endif
1008 
1009 static struct virtio_device_id id_table[] = {
1010         { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
1011         { 0 },
1012 };
1013 
1014 static unsigned int features[] = {
1015         VIRTIO_SCSI_F_HOTPLUG,
1016         VIRTIO_SCSI_F_CHANGE,
1017         VIRTIO_SCSI_F_T10_PI,
1018 };
1019 
1020 static struct virtio_driver virtio_scsi_driver = {
1021         .feature_table = features,
1022         .feature_table_size = ARRAY_SIZE(features),
1023         .driver.name = KBUILD_MODNAME,
1024         .driver.owner = THIS_MODULE,
1025         .id_table = id_table,
1026         .probe = virtscsi_probe,
1027         .scan = virtscsi_scan,
1028 #ifdef CONFIG_PM_SLEEP
1029         .freeze = virtscsi_freeze,
1030         .restore = virtscsi_restore,
1031 #endif
1032         .remove = virtscsi_remove,
1033 };
1034 
1035 static int __init init(void)
1036 {
1037         int ret = -ENOMEM;
1038 
1039         virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
1040         if (!virtscsi_cmd_cache) {
1041                 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
1042                 goto error;
1043         }
1044 
1045 
1046         virtscsi_cmd_pool =
1047                 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
1048                                          virtscsi_cmd_cache);
1049         if (!virtscsi_cmd_pool) {
1050                 pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
1051                 goto error;
1052         }
1053         ret = register_virtio_driver(&virtio_scsi_driver);
1054         if (ret < 0)
1055                 goto error;
1056 
1057         return 0;
1058 
1059 error:
1060         if (virtscsi_cmd_pool) {
1061                 mempool_destroy(virtscsi_cmd_pool);
1062                 virtscsi_cmd_pool = NULL;
1063         }
1064         if (virtscsi_cmd_cache) {
1065                 kmem_cache_destroy(virtscsi_cmd_cache);
1066                 virtscsi_cmd_cache = NULL;
1067         }
1068         return ret;
1069 }
1070 
1071 static void __exit fini(void)
1072 {
1073         unregister_virtio_driver(&virtio_scsi_driver);
1074         mempool_destroy(virtscsi_cmd_pool);
1075         kmem_cache_destroy(virtscsi_cmd_cache);
1076 }
1077 module_init(init);
1078 module_exit(fini);
1079 
1080 MODULE_DEVICE_TABLE(virtio, id_table);
1081 MODULE_DESCRIPTION("Virtio SCSI HBA driver");
1082 MODULE_LICENSE("GPL");
1083 

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