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31#include <linux/module.h>
32#include <linux/kernel.h>
33#include <linux/device.h>
34#include <linux/wait.h>
35#include <linux/interrupt.h>
36#include <linux/mutex.h>
37#include <linux/spinlock.h>
38#include <linux/sched.h>
39#include <linux/blkdev.h>
40#include <linux/pfn.h>
41#include <linux/slab.h>
42#include <linux/bitops.h>
43
44#include <scsi/scsi_cmnd.h>
45#include <scsi/scsi_device.h>
46#include <scsi/scsi.h>
47#include <scsi/scsi_host.h>
48
49#include <xen/xen.h>
50#include <xen/xenbus.h>
51#include <xen/grant_table.h>
52#include <xen/events.h>
53#include <xen/page.h>
54
55#include <xen/interface/grant_table.h>
56#include <xen/interface/io/vscsiif.h>
57#include <xen/interface/io/protocols.h>
58
59#include <asm/xen/hypervisor.h>
60
61
62#define GRANT_INVALID_REF 0
63
64#define VSCSIFRONT_OP_ADD_LUN 1
65#define VSCSIFRONT_OP_DEL_LUN 2
66#define VSCSIFRONT_OP_READD_LUN 3
67
68
69#define VSCSIIF_DEFAULT_CMD_PER_LUN 10
70#define VSCSIIF_MAX_TARGET 64
71#define VSCSIIF_MAX_LUN 255
72
73#define VSCSIIF_RING_SIZE __CONST_RING_SIZE(vscsiif, PAGE_SIZE)
74#define VSCSIIF_MAX_REQS VSCSIIF_RING_SIZE
75
76#define vscsiif_grants_sg(_sg) (PFN_UP((_sg) * \
77 sizeof(struct scsiif_request_segment)))
78
79struct vscsifrnt_shadow {
80
81 unsigned char act;
82 uint8_t nr_segments;
83 uint16_t rqid;
84 uint16_t ref_rqid;
85
86 unsigned int nr_grants;
87 struct scsiif_request_segment *sg;
88 struct scsiif_request_segment seg[VSCSIIF_SG_TABLESIZE];
89
90
91 wait_queue_head_t wq_reset;
92 int wait_reset;
93 int32_t rslt_reset;
94
95#define RSLT_RESET_WAITING 0
96#define RSLT_RESET_ERR -1
97
98
99 struct scsi_cmnd *sc;
100 int gref[vscsiif_grants_sg(SG_ALL) + SG_ALL];
101};
102
103struct vscsifrnt_info {
104 struct xenbus_device *dev;
105
106 struct Scsi_Host *host;
107 int host_active;
108
109 unsigned int evtchn;
110 unsigned int irq;
111
112 grant_ref_t ring_ref;
113 struct vscsiif_front_ring ring;
114 struct vscsiif_response ring_rsp;
115
116 spinlock_t shadow_lock;
117 DECLARE_BITMAP(shadow_free_bitmap, VSCSIIF_MAX_REQS);
118 struct vscsifrnt_shadow *shadow[VSCSIIF_MAX_REQS];
119
120
121 wait_queue_head_t wq_sync;
122 wait_queue_head_t wq_pause;
123 unsigned int wait_ring_available:1;
124 unsigned int waiting_pause:1;
125 unsigned int pause:1;
126 unsigned callers;
127
128 char dev_state_path[64];
129 struct task_struct *curr;
130};
131
132static DEFINE_MUTEX(scsifront_mutex);
133
134static void scsifront_wake_up(struct vscsifrnt_info *info)
135{
136 info->wait_ring_available = 0;
137 wake_up(&info->wq_sync);
138}
139
140static int scsifront_get_rqid(struct vscsifrnt_info *info)
141{
142 unsigned long flags;
143 int free;
144
145 spin_lock_irqsave(&info->shadow_lock, flags);
146
147 free = find_first_bit(info->shadow_free_bitmap, VSCSIIF_MAX_REQS);
148 __clear_bit(free, info->shadow_free_bitmap);
149
150 spin_unlock_irqrestore(&info->shadow_lock, flags);
151
152 return free;
153}
154
155static int _scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id)
156{
157 int empty = bitmap_empty(info->shadow_free_bitmap, VSCSIIF_MAX_REQS);
158
159 __set_bit(id, info->shadow_free_bitmap);
160 info->shadow[id] = NULL;
161
162 return empty || info->wait_ring_available;
163}
164
165static void scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id)
166{
167 unsigned long flags;
168 int kick;
169
170 spin_lock_irqsave(&info->shadow_lock, flags);
171 kick = _scsifront_put_rqid(info, id);
172 spin_unlock_irqrestore(&info->shadow_lock, flags);
173
174 if (kick)
175 scsifront_wake_up(info);
176}
177
178static int scsifront_do_request(struct vscsifrnt_info *info,
179 struct vscsifrnt_shadow *shadow)
180{
181 struct vscsiif_front_ring *ring = &(info->ring);
182 struct vscsiif_request *ring_req;
183 struct scsi_cmnd *sc = shadow->sc;
184 uint32_t id;
185 int i, notify;
186
187 if (RING_FULL(&info->ring))
188 return -EBUSY;
189
190 id = scsifront_get_rqid(info);
191 if (id >= VSCSIIF_MAX_REQS)
192 return -EBUSY;
193
194 info->shadow[id] = shadow;
195 shadow->rqid = id;
196
197 ring_req = RING_GET_REQUEST(&(info->ring), ring->req_prod_pvt);
198 ring->req_prod_pvt++;
199
200 ring_req->rqid = id;
201 ring_req->act = shadow->act;
202 ring_req->ref_rqid = shadow->ref_rqid;
203 ring_req->nr_segments = shadow->nr_segments;
204
205 ring_req->id = sc->device->id;
206 ring_req->lun = sc->device->lun;
207 ring_req->channel = sc->device->channel;
208 ring_req->cmd_len = sc->cmd_len;
209
210 BUG_ON(sc->cmd_len > VSCSIIF_MAX_COMMAND_SIZE);
211
212 memcpy(ring_req->cmnd, sc->cmnd, sc->cmd_len);
213
214 ring_req->sc_data_direction = (uint8_t)sc->sc_data_direction;
215 ring_req->timeout_per_command = scsi_cmd_to_rq(sc)->timeout / HZ;
216
217 for (i = 0; i < (shadow->nr_segments & ~VSCSIIF_SG_GRANT); i++)
218 ring_req->seg[i] = shadow->seg[i];
219
220 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(ring, notify);
221 if (notify)
222 notify_remote_via_irq(info->irq);
223
224 return 0;
225}
226
227static void scsifront_gnttab_done(struct vscsifrnt_info *info,
228 struct vscsifrnt_shadow *shadow)
229{
230 int i;
231
232 if (shadow->sc->sc_data_direction == DMA_NONE)
233 return;
234
235 for (i = 0; i < shadow->nr_grants; i++) {
236 if (unlikely(gnttab_query_foreign_access(shadow->gref[i]))) {
237 shost_printk(KERN_ALERT, info->host, KBUILD_MODNAME
238 "grant still in use by backend\n");
239 BUG();
240 }
241 gnttab_end_foreign_access(shadow->gref[i], 0, 0UL);
242 }
243
244 kfree(shadow->sg);
245}
246
247static void scsifront_cdb_cmd_done(struct vscsifrnt_info *info,
248 struct vscsiif_response *ring_rsp)
249{
250 struct vscsifrnt_shadow *shadow;
251 struct scsi_cmnd *sc;
252 uint32_t id;
253 uint8_t sense_len;
254 int result;
255
256 id = ring_rsp->rqid;
257 shadow = info->shadow[id];
258 sc = shadow->sc;
259
260 BUG_ON(sc == NULL);
261
262 scsifront_gnttab_done(info, shadow);
263 scsifront_put_rqid(info, id);
264
265 result = ring_rsp->rslt;
266 if (result >> 24)
267 set_host_byte(sc, DID_ERROR);
268 else
269 set_host_byte(sc, host_byte(result));
270 set_status_byte(sc, result & 0xff);
271 scsi_set_resid(sc, ring_rsp->residual_len);
272
273 sense_len = min_t(uint8_t, VSCSIIF_SENSE_BUFFERSIZE,
274 ring_rsp->sense_len);
275
276 if (sense_len)
277 memcpy(sc->sense_buffer, ring_rsp->sense_buffer, sense_len);
278
279 sc->scsi_done(sc);
280}
281
282static void scsifront_sync_cmd_done(struct vscsifrnt_info *info,
283 struct vscsiif_response *ring_rsp)
284{
285 uint16_t id = ring_rsp->rqid;
286 unsigned long flags;
287 struct vscsifrnt_shadow *shadow = info->shadow[id];
288 int kick;
289
290 spin_lock_irqsave(&info->shadow_lock, flags);
291 shadow->wait_reset = 1;
292 switch (shadow->rslt_reset) {
293 case RSLT_RESET_WAITING:
294 shadow->rslt_reset = ring_rsp->rslt;
295 break;
296 case RSLT_RESET_ERR:
297 kick = _scsifront_put_rqid(info, id);
298 spin_unlock_irqrestore(&info->shadow_lock, flags);
299 kfree(shadow);
300 if (kick)
301 scsifront_wake_up(info);
302 return;
303 default:
304 shost_printk(KERN_ERR, info->host, KBUILD_MODNAME
305 "bad reset state %d, possibly leaking %u\n",
306 shadow->rslt_reset, id);
307 break;
308 }
309 spin_unlock_irqrestore(&info->shadow_lock, flags);
310
311 wake_up(&shadow->wq_reset);
312}
313
314static void scsifront_do_response(struct vscsifrnt_info *info,
315 struct vscsiif_response *ring_rsp)
316{
317 if (WARN(ring_rsp->rqid >= VSCSIIF_MAX_REQS ||
318 test_bit(ring_rsp->rqid, info->shadow_free_bitmap),
319 "illegal rqid %u returned by backend!\n", ring_rsp->rqid))
320 return;
321
322 if (info->shadow[ring_rsp->rqid]->act == VSCSIIF_ACT_SCSI_CDB)
323 scsifront_cdb_cmd_done(info, ring_rsp);
324 else
325 scsifront_sync_cmd_done(info, ring_rsp);
326}
327
328static int scsifront_ring_drain(struct vscsifrnt_info *info)
329{
330 struct vscsiif_response *ring_rsp;
331 RING_IDX i, rp;
332 int more_to_do = 0;
333
334 rp = info->ring.sring->rsp_prod;
335 rmb();
336 for (i = info->ring.rsp_cons; i != rp; i++) {
337 ring_rsp = RING_GET_RESPONSE(&info->ring, i);
338 scsifront_do_response(info, ring_rsp);
339 }
340
341 info->ring.rsp_cons = i;
342
343 if (i != info->ring.req_prod_pvt)
344 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
345 else
346 info->ring.sring->rsp_event = i + 1;
347
348 return more_to_do;
349}
350
351static int scsifront_cmd_done(struct vscsifrnt_info *info)
352{
353 int more_to_do;
354 unsigned long flags;
355
356 spin_lock_irqsave(info->host->host_lock, flags);
357
358 more_to_do = scsifront_ring_drain(info);
359
360 info->wait_ring_available = 0;
361
362 spin_unlock_irqrestore(info->host->host_lock, flags);
363
364 wake_up(&info->wq_sync);
365
366 return more_to_do;
367}
368
369static irqreturn_t scsifront_irq_fn(int irq, void *dev_id)
370{
371 struct vscsifrnt_info *info = dev_id;
372
373 while (scsifront_cmd_done(info))
374
375 cond_resched();
376
377 return IRQ_HANDLED;
378}
379
380static void scsifront_finish_all(struct vscsifrnt_info *info)
381{
382 unsigned i;
383 struct vscsiif_response resp;
384
385 scsifront_ring_drain(info);
386
387 for (i = 0; i < VSCSIIF_MAX_REQS; i++) {
388 if (test_bit(i, info->shadow_free_bitmap))
389 continue;
390 resp.rqid = i;
391 resp.sense_len = 0;
392 resp.rslt = DID_RESET << 16;
393 resp.residual_len = 0;
394 scsifront_do_response(info, &resp);
395 }
396}
397
398static int map_data_for_request(struct vscsifrnt_info *info,
399 struct scsi_cmnd *sc,
400 struct vscsifrnt_shadow *shadow)
401{
402 grant_ref_t gref_head;
403 struct page *page;
404 int err, ref, ref_cnt = 0;
405 int grant_ro = (sc->sc_data_direction == DMA_TO_DEVICE);
406 unsigned int i, off, len, bytes;
407 unsigned int data_len = scsi_bufflen(sc);
408 unsigned int data_grants = 0, seg_grants = 0;
409 struct scatterlist *sg;
410 struct scsiif_request_segment *seg;
411
412 if (sc->sc_data_direction == DMA_NONE || !data_len)
413 return 0;
414
415 scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i)
416 data_grants += PFN_UP(sg->offset + sg->length);
417
418 if (data_grants > VSCSIIF_SG_TABLESIZE) {
419 if (data_grants > info->host->sg_tablesize) {
420 shost_printk(KERN_ERR, info->host, KBUILD_MODNAME
421 "Unable to map request_buffer for command!\n");
422 return -E2BIG;
423 }
424 seg_grants = vscsiif_grants_sg(data_grants);
425 shadow->sg = kcalloc(data_grants,
426 sizeof(struct scsiif_request_segment), GFP_ATOMIC);
427 if (!shadow->sg)
428 return -ENOMEM;
429 }
430 seg = shadow->sg ? : shadow->seg;
431
432 err = gnttab_alloc_grant_references(seg_grants + data_grants,
433 &gref_head);
434 if (err) {
435 kfree(shadow->sg);
436 shost_printk(KERN_ERR, info->host, KBUILD_MODNAME
437 "gnttab_alloc_grant_references() error\n");
438 return -ENOMEM;
439 }
440
441 if (seg_grants) {
442 page = virt_to_page(seg);
443 off = offset_in_page(seg);
444 len = sizeof(struct scsiif_request_segment) * data_grants;
445 while (len > 0) {
446 bytes = min_t(unsigned int, len, PAGE_SIZE - off);
447
448 ref = gnttab_claim_grant_reference(&gref_head);
449 BUG_ON(ref == -ENOSPC);
450
451 gnttab_grant_foreign_access_ref(ref,
452 info->dev->otherend_id,
453 xen_page_to_gfn(page), 1);
454 shadow->gref[ref_cnt] = ref;
455 shadow->seg[ref_cnt].gref = ref;
456 shadow->seg[ref_cnt].offset = (uint16_t)off;
457 shadow->seg[ref_cnt].length = (uint16_t)bytes;
458
459 page++;
460 len -= bytes;
461 off = 0;
462 ref_cnt++;
463 }
464 BUG_ON(seg_grants < ref_cnt);
465 seg_grants = ref_cnt;
466 }
467
468 scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i) {
469 page = sg_page(sg);
470 off = sg->offset;
471 len = sg->length;
472
473 while (len > 0 && data_len > 0) {
474
475
476
477
478
479 bytes = min_t(unsigned int, len, PAGE_SIZE - off);
480 bytes = min(bytes, data_len);
481
482 ref = gnttab_claim_grant_reference(&gref_head);
483 BUG_ON(ref == -ENOSPC);
484
485 gnttab_grant_foreign_access_ref(ref,
486 info->dev->otherend_id,
487 xen_page_to_gfn(page),
488 grant_ro);
489
490 shadow->gref[ref_cnt] = ref;
491 seg->gref = ref;
492 seg->offset = (uint16_t)off;
493 seg->length = (uint16_t)bytes;
494
495 page++;
496 seg++;
497 len -= bytes;
498 data_len -= bytes;
499 off = 0;
500 ref_cnt++;
501 }
502 }
503
504 if (seg_grants)
505 shadow->nr_segments = VSCSIIF_SG_GRANT | seg_grants;
506 else
507 shadow->nr_segments = (uint8_t)ref_cnt;
508 shadow->nr_grants = ref_cnt;
509
510 return 0;
511}
512
513static int scsifront_enter(struct vscsifrnt_info *info)
514{
515 if (info->pause)
516 return 1;
517 info->callers++;
518 return 0;
519}
520
521static void scsifront_return(struct vscsifrnt_info *info)
522{
523 info->callers--;
524 if (info->callers)
525 return;
526
527 if (!info->waiting_pause)
528 return;
529
530 info->waiting_pause = 0;
531 wake_up(&info->wq_pause);
532}
533
534static int scsifront_queuecommand(struct Scsi_Host *shost,
535 struct scsi_cmnd *sc)
536{
537 struct vscsifrnt_info *info = shost_priv(shost);
538 struct vscsifrnt_shadow *shadow = scsi_cmd_priv(sc);
539 unsigned long flags;
540 int err;
541
542 sc->result = 0;
543
544 shadow->sc = sc;
545 shadow->act = VSCSIIF_ACT_SCSI_CDB;
546
547 spin_lock_irqsave(shost->host_lock, flags);
548 if (scsifront_enter(info)) {
549 spin_unlock_irqrestore(shost->host_lock, flags);
550 return SCSI_MLQUEUE_HOST_BUSY;
551 }
552
553 err = map_data_for_request(info, sc, shadow);
554 if (err < 0) {
555 pr_debug("%s: err %d\n", __func__, err);
556 scsifront_return(info);
557 spin_unlock_irqrestore(shost->host_lock, flags);
558 if (err == -ENOMEM)
559 return SCSI_MLQUEUE_HOST_BUSY;
560 sc->result = DID_ERROR << 16;
561 sc->scsi_done(sc);
562 return 0;
563 }
564
565 if (scsifront_do_request(info, shadow)) {
566 scsifront_gnttab_done(info, shadow);
567 goto busy;
568 }
569
570 scsifront_return(info);
571 spin_unlock_irqrestore(shost->host_lock, flags);
572
573 return 0;
574
575busy:
576 scsifront_return(info);
577 spin_unlock_irqrestore(shost->host_lock, flags);
578 pr_debug("%s: busy\n", __func__);
579 return SCSI_MLQUEUE_HOST_BUSY;
580}
581
582
583
584
585
586
587static int scsifront_action_handler(struct scsi_cmnd *sc, uint8_t act)
588{
589 struct Scsi_Host *host = sc->device->host;
590 struct vscsifrnt_info *info = shost_priv(host);
591 struct vscsifrnt_shadow *shadow, *s = scsi_cmd_priv(sc);
592 int err = 0;
593
594 shadow = kzalloc(sizeof(*shadow), GFP_NOIO);
595 if (!shadow)
596 return FAILED;
597
598 shadow->act = act;
599 shadow->rslt_reset = RSLT_RESET_WAITING;
600 shadow->sc = sc;
601 shadow->ref_rqid = s->rqid;
602 init_waitqueue_head(&shadow->wq_reset);
603
604 spin_lock_irq(host->host_lock);
605
606 for (;;) {
607 if (scsifront_enter(info))
608 goto fail;
609
610 if (!scsifront_do_request(info, shadow))
611 break;
612
613 scsifront_return(info);
614 if (err)
615 goto fail;
616 info->wait_ring_available = 1;
617 spin_unlock_irq(host->host_lock);
618 err = wait_event_interruptible(info->wq_sync,
619 !info->wait_ring_available);
620 spin_lock_irq(host->host_lock);
621 }
622
623 spin_unlock_irq(host->host_lock);
624 err = wait_event_interruptible(shadow->wq_reset, shadow->wait_reset);
625 spin_lock_irq(host->host_lock);
626
627 if (!err) {
628 err = shadow->rslt_reset;
629 scsifront_put_rqid(info, shadow->rqid);
630 kfree(shadow);
631 } else {
632 spin_lock(&info->shadow_lock);
633 shadow->rslt_reset = RSLT_RESET_ERR;
634 spin_unlock(&info->shadow_lock);
635 err = FAILED;
636 }
637
638 scsifront_return(info);
639 spin_unlock_irq(host->host_lock);
640 return err;
641
642fail:
643 spin_unlock_irq(host->host_lock);
644 kfree(shadow);
645 return FAILED;
646}
647
648static int scsifront_eh_abort_handler(struct scsi_cmnd *sc)
649{
650 pr_debug("%s\n", __func__);
651 return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_ABORT);
652}
653
654static int scsifront_dev_reset_handler(struct scsi_cmnd *sc)
655{
656 pr_debug("%s\n", __func__);
657 return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_RESET);
658}
659
660static int scsifront_sdev_configure(struct scsi_device *sdev)
661{
662 struct vscsifrnt_info *info = shost_priv(sdev->host);
663 int err;
664
665 if (info && current == info->curr) {
666 err = xenbus_printf(XBT_NIL, info->dev->nodename,
667 info->dev_state_path, "%d", XenbusStateConnected);
668 if (err) {
669 xenbus_dev_error(info->dev, err,
670 "%s: writing dev_state_path", __func__);
671 return err;
672 }
673 }
674
675 return 0;
676}
677
678static void scsifront_sdev_destroy(struct scsi_device *sdev)
679{
680 struct vscsifrnt_info *info = shost_priv(sdev->host);
681 int err;
682
683 if (info && current == info->curr) {
684 err = xenbus_printf(XBT_NIL, info->dev->nodename,
685 info->dev_state_path, "%d", XenbusStateClosed);
686 if (err)
687 xenbus_dev_error(info->dev, err,
688 "%s: writing dev_state_path", __func__);
689 }
690}
691
692static struct scsi_host_template scsifront_sht = {
693 .module = THIS_MODULE,
694 .name = "Xen SCSI frontend driver",
695 .queuecommand = scsifront_queuecommand,
696 .eh_abort_handler = scsifront_eh_abort_handler,
697 .eh_device_reset_handler = scsifront_dev_reset_handler,
698 .slave_configure = scsifront_sdev_configure,
699 .slave_destroy = scsifront_sdev_destroy,
700 .cmd_per_lun = VSCSIIF_DEFAULT_CMD_PER_LUN,
701 .can_queue = VSCSIIF_MAX_REQS,
702 .this_id = -1,
703 .cmd_size = sizeof(struct vscsifrnt_shadow),
704 .sg_tablesize = VSCSIIF_SG_TABLESIZE,
705 .proc_name = "scsifront",
706};
707
708static int scsifront_alloc_ring(struct vscsifrnt_info *info)
709{
710 struct xenbus_device *dev = info->dev;
711 struct vscsiif_sring *sring;
712 grant_ref_t gref;
713 int err = -ENOMEM;
714
715
716 sring = (struct vscsiif_sring *)__get_free_page(GFP_KERNEL);
717 if (!sring) {
718 xenbus_dev_fatal(dev, err,
719 "fail to allocate shared ring (Front to Back)");
720 return err;
721 }
722 SHARED_RING_INIT(sring);
723 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
724
725 err = xenbus_grant_ring(dev, sring, 1, &gref);
726 if (err < 0) {
727 free_page((unsigned long)sring);
728 xenbus_dev_fatal(dev, err,
729 "fail to grant shared ring (Front to Back)");
730 return err;
731 }
732 info->ring_ref = gref;
733
734 err = xenbus_alloc_evtchn(dev, &info->evtchn);
735 if (err) {
736 xenbus_dev_fatal(dev, err, "xenbus_alloc_evtchn");
737 goto free_gnttab;
738 }
739
740 err = bind_evtchn_to_irq(info->evtchn);
741 if (err <= 0) {
742 xenbus_dev_fatal(dev, err, "bind_evtchn_to_irq");
743 goto free_gnttab;
744 }
745
746 info->irq = err;
747
748 err = request_threaded_irq(info->irq, NULL, scsifront_irq_fn,
749 IRQF_ONESHOT, "scsifront", info);
750 if (err) {
751 xenbus_dev_fatal(dev, err, "request_threaded_irq");
752 goto free_irq;
753 }
754
755 return 0;
756
757
758free_irq:
759 unbind_from_irqhandler(info->irq, info);
760free_gnttab:
761 gnttab_end_foreign_access(info->ring_ref, 0,
762 (unsigned long)info->ring.sring);
763
764 return err;
765}
766
767static void scsifront_free_ring(struct vscsifrnt_info *info)
768{
769 unbind_from_irqhandler(info->irq, info);
770 gnttab_end_foreign_access(info->ring_ref, 0,
771 (unsigned long)info->ring.sring);
772}
773
774static int scsifront_init_ring(struct vscsifrnt_info *info)
775{
776 struct xenbus_device *dev = info->dev;
777 struct xenbus_transaction xbt;
778 int err;
779
780 pr_debug("%s\n", __func__);
781
782 err = scsifront_alloc_ring(info);
783 if (err)
784 return err;
785 pr_debug("%s: %u %u\n", __func__, info->ring_ref, info->evtchn);
786
787again:
788 err = xenbus_transaction_start(&xbt);
789 if (err)
790 xenbus_dev_fatal(dev, err, "starting transaction");
791
792 err = xenbus_printf(xbt, dev->nodename, "ring-ref", "%u",
793 info->ring_ref);
794 if (err) {
795 xenbus_dev_fatal(dev, err, "%s", "writing ring-ref");
796 goto fail;
797 }
798
799 err = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
800 info->evtchn);
801
802 if (err) {
803 xenbus_dev_fatal(dev, err, "%s", "writing event-channel");
804 goto fail;
805 }
806
807 err = xenbus_transaction_end(xbt, 0);
808 if (err) {
809 if (err == -EAGAIN)
810 goto again;
811 xenbus_dev_fatal(dev, err, "completing transaction");
812 goto free_sring;
813 }
814
815 return 0;
816
817fail:
818 xenbus_transaction_end(xbt, 1);
819free_sring:
820 scsifront_free_ring(info);
821
822 return err;
823}
824
825
826static int scsifront_probe(struct xenbus_device *dev,
827 const struct xenbus_device_id *id)
828{
829 struct vscsifrnt_info *info;
830 struct Scsi_Host *host;
831 int err = -ENOMEM;
832 char name[TASK_COMM_LEN];
833
834 host = scsi_host_alloc(&scsifront_sht, sizeof(*info));
835 if (!host) {
836 xenbus_dev_fatal(dev, err, "fail to allocate scsi host");
837 return err;
838 }
839 info = (struct vscsifrnt_info *)host->hostdata;
840
841 dev_set_drvdata(&dev->dev, info);
842 info->dev = dev;
843
844 bitmap_fill(info->shadow_free_bitmap, VSCSIIF_MAX_REQS);
845
846 err = scsifront_init_ring(info);
847 if (err) {
848 scsi_host_put(host);
849 return err;
850 }
851
852 init_waitqueue_head(&info->wq_sync);
853 init_waitqueue_head(&info->wq_pause);
854 spin_lock_init(&info->shadow_lock);
855
856 snprintf(name, TASK_COMM_LEN, "vscsiif.%d", host->host_no);
857
858 host->max_id = VSCSIIF_MAX_TARGET;
859 host->max_channel = 0;
860 host->max_lun = VSCSIIF_MAX_LUN;
861 host->max_sectors = (host->sg_tablesize - 1) * PAGE_SIZE / 512;
862 host->max_cmd_len = VSCSIIF_MAX_COMMAND_SIZE;
863
864 err = scsi_add_host(host, &dev->dev);
865 if (err) {
866 dev_err(&dev->dev, "fail to add scsi host %d\n", err);
867 goto free_sring;
868 }
869 info->host = host;
870 info->host_active = 1;
871
872 xenbus_switch_state(dev, XenbusStateInitialised);
873
874 return 0;
875
876free_sring:
877 scsifront_free_ring(info);
878 scsi_host_put(host);
879 return err;
880}
881
882static int scsifront_resume(struct xenbus_device *dev)
883{
884 struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
885 struct Scsi_Host *host = info->host;
886 int err;
887
888 spin_lock_irq(host->host_lock);
889
890
891 scsifront_finish_all(info);
892
893 spin_unlock_irq(host->host_lock);
894
895
896 scsifront_free_ring(info);
897 err = scsifront_init_ring(info);
898 if (err) {
899 dev_err(&dev->dev, "fail to resume %d\n", err);
900 scsi_host_put(host);
901 return err;
902 }
903
904 xenbus_switch_state(dev, XenbusStateInitialised);
905
906 return 0;
907}
908
909static int scsifront_suspend(struct xenbus_device *dev)
910{
911 struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
912 struct Scsi_Host *host = info->host;
913 int err = 0;
914
915
916 spin_lock_irq(host->host_lock);
917 info->pause = 1;
918 while (info->callers && !err) {
919 info->waiting_pause = 1;
920 info->wait_ring_available = 0;
921 spin_unlock_irq(host->host_lock);
922 wake_up(&info->wq_sync);
923 err = wait_event_interruptible(info->wq_pause,
924 !info->waiting_pause);
925 spin_lock_irq(host->host_lock);
926 }
927 spin_unlock_irq(host->host_lock);
928 return err;
929}
930
931static int scsifront_remove(struct xenbus_device *dev)
932{
933 struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
934
935 pr_debug("%s: %s removed\n", __func__, dev->nodename);
936
937 mutex_lock(&scsifront_mutex);
938 if (info->host_active) {
939
940 scsi_remove_host(info->host);
941 info->host_active = 0;
942 }
943 mutex_unlock(&scsifront_mutex);
944
945 scsifront_free_ring(info);
946 scsi_host_put(info->host);
947
948 return 0;
949}
950
951static void scsifront_disconnect(struct vscsifrnt_info *info)
952{
953 struct xenbus_device *dev = info->dev;
954 struct Scsi_Host *host = info->host;
955
956 pr_debug("%s: %s disconnect\n", __func__, dev->nodename);
957
958
959
960
961
962
963
964 mutex_lock(&scsifront_mutex);
965 if (info->host_active) {
966 scsi_remove_host(host);
967 info->host_active = 0;
968 }
969 mutex_unlock(&scsifront_mutex);
970
971 xenbus_frontend_closed(dev);
972}
973
974static void scsifront_do_lun_hotplug(struct vscsifrnt_info *info, int op)
975{
976 struct xenbus_device *dev = info->dev;
977 int i, err = 0;
978 char str[64];
979 char **dir;
980 unsigned int dir_n = 0;
981 unsigned int device_state;
982 unsigned int hst, chn, tgt, lun;
983 struct scsi_device *sdev;
984
985 dir = xenbus_directory(XBT_NIL, dev->otherend, "vscsi-devs", &dir_n);
986 if (IS_ERR(dir))
987 return;
988
989
990 BUG_ON(info->curr);
991 info->curr = current;
992
993 for (i = 0; i < dir_n; i++) {
994
995 snprintf(str, sizeof(str), "vscsi-devs/%s/state", dir[i]);
996 err = xenbus_scanf(XBT_NIL, dev->otherend, str, "%u",
997 &device_state);
998 if (XENBUS_EXIST_ERR(err))
999 continue;
1000
1001
1002 snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", dir[i]);
1003 err = xenbus_scanf(XBT_NIL, dev->otherend, str,
1004 "%u:%u:%u:%u", &hst, &chn, &tgt, &lun);
1005 if (XENBUS_EXIST_ERR(err))
1006 continue;
1007
1008
1009
1010
1011
1012
1013 snprintf(info->dev_state_path, sizeof(info->dev_state_path),
1014 "vscsi-devs/%s/state", dir[i]);
1015
1016 switch (op) {
1017 case VSCSIFRONT_OP_ADD_LUN:
1018 if (device_state != XenbusStateInitialised)
1019 break;
1020
1021 if (scsi_add_device(info->host, chn, tgt, lun)) {
1022 dev_err(&dev->dev, "scsi_add_device\n");
1023 err = xenbus_printf(XBT_NIL, dev->nodename,
1024 info->dev_state_path,
1025 "%d", XenbusStateClosed);
1026 if (err)
1027 xenbus_dev_error(dev, err,
1028 "%s: writing dev_state_path", __func__);
1029 }
1030 break;
1031 case VSCSIFRONT_OP_DEL_LUN:
1032 if (device_state != XenbusStateClosing)
1033 break;
1034
1035 sdev = scsi_device_lookup(info->host, chn, tgt, lun);
1036 if (sdev) {
1037 scsi_remove_device(sdev);
1038 scsi_device_put(sdev);
1039 }
1040 break;
1041 case VSCSIFRONT_OP_READD_LUN:
1042 if (device_state == XenbusStateConnected) {
1043 err = xenbus_printf(XBT_NIL, dev->nodename,
1044 info->dev_state_path,
1045 "%d", XenbusStateConnected);
1046 if (err)
1047 xenbus_dev_error(dev, err,
1048 "%s: writing dev_state_path", __func__);
1049 }
1050 break;
1051 default:
1052 break;
1053 }
1054 }
1055
1056 info->curr = NULL;
1057
1058 kfree(dir);
1059}
1060
1061static void scsifront_read_backend_params(struct xenbus_device *dev,
1062 struct vscsifrnt_info *info)
1063{
1064 unsigned int sg_grant, nr_segs;
1065 struct Scsi_Host *host = info->host;
1066
1067 sg_grant = xenbus_read_unsigned(dev->otherend, "feature-sg-grant", 0);
1068 nr_segs = min_t(unsigned int, sg_grant, SG_ALL);
1069 nr_segs = max_t(unsigned int, nr_segs, VSCSIIF_SG_TABLESIZE);
1070 nr_segs = min_t(unsigned int, nr_segs,
1071 VSCSIIF_SG_TABLESIZE * PAGE_SIZE /
1072 sizeof(struct scsiif_request_segment));
1073
1074 if (!info->pause && sg_grant)
1075 dev_info(&dev->dev, "using up to %d SG entries\n", nr_segs);
1076 else if (info->pause && nr_segs < host->sg_tablesize)
1077 dev_warn(&dev->dev,
1078 "SG entries decreased from %d to %u - device may not work properly anymore\n",
1079 host->sg_tablesize, nr_segs);
1080
1081 host->sg_tablesize = nr_segs;
1082 host->max_sectors = (nr_segs - 1) * PAGE_SIZE / 512;
1083}
1084
1085static void scsifront_backend_changed(struct xenbus_device *dev,
1086 enum xenbus_state backend_state)
1087{
1088 struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
1089
1090 pr_debug("%s: %p %u %u\n", __func__, dev, dev->state, backend_state);
1091
1092 switch (backend_state) {
1093 case XenbusStateUnknown:
1094 case XenbusStateInitialising:
1095 case XenbusStateInitWait:
1096 case XenbusStateInitialised:
1097 break;
1098
1099 case XenbusStateConnected:
1100 scsifront_read_backend_params(dev, info);
1101
1102 if (info->pause) {
1103 scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_READD_LUN);
1104 xenbus_switch_state(dev, XenbusStateConnected);
1105 info->pause = 0;
1106 return;
1107 }
1108
1109 if (xenbus_read_driver_state(dev->nodename) ==
1110 XenbusStateInitialised)
1111 scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN);
1112
1113 if (dev->state != XenbusStateConnected)
1114 xenbus_switch_state(dev, XenbusStateConnected);
1115 break;
1116
1117 case XenbusStateClosed:
1118 if (dev->state == XenbusStateClosed)
1119 break;
1120 fallthrough;
1121 case XenbusStateClosing:
1122 scsifront_disconnect(info);
1123 break;
1124
1125 case XenbusStateReconfiguring:
1126 scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_DEL_LUN);
1127 xenbus_switch_state(dev, XenbusStateReconfiguring);
1128 break;
1129
1130 case XenbusStateReconfigured:
1131 scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN);
1132 xenbus_switch_state(dev, XenbusStateConnected);
1133 break;
1134 }
1135}
1136
1137static const struct xenbus_device_id scsifront_ids[] = {
1138 { "vscsi" },
1139 { "" }
1140};
1141
1142static struct xenbus_driver scsifront_driver = {
1143 .ids = scsifront_ids,
1144 .probe = scsifront_probe,
1145 .remove = scsifront_remove,
1146 .resume = scsifront_resume,
1147 .suspend = scsifront_suspend,
1148 .otherend_changed = scsifront_backend_changed,
1149};
1150
1151static int __init scsifront_init(void)
1152{
1153 if (!xen_domain())
1154 return -ENODEV;
1155
1156 return xenbus_register_frontend(&scsifront_driver);
1157}
1158module_init(scsifront_init);
1159
1160static void __exit scsifront_exit(void)
1161{
1162 xenbus_unregister_driver(&scsifront_driver);
1163}
1164module_exit(scsifront_exit);
1165
1166MODULE_DESCRIPTION("Xen SCSI frontend driver");
1167MODULE_LICENSE("GPL");
1168MODULE_ALIAS("xen:vscsi");
1169MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");
1170
