2 * Xen SCSI frontend driver
4 * Copyright (c) 2008, FUJITSU Limited
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License version 2
8 * as published by the Free Software Foundation; or, when distributed
9 * separately from the Linux kernel or incorporated into other
10 * software packages, subject to the following license:
12 * Permission is hereby granted, free of charge, to any person obtaining a copy
13 * of this source file (the "Software"), to deal in the Software without
14 * restriction, including without limitation the rights to use, copy, modify,
15 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
16 * and to permit persons to whom the Software is furnished to do so, subject to
17 * the following conditions:
19 * The above copyright notice and this permission notice shall be included in
20 * all copies or substantial portions of the Software.
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
27 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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>
44 #include <scsi/scsi_cmnd.h>
45 #include <scsi/scsi_device.h>
46 #include <scsi/scsi.h>
47 #include <scsi/scsi_host.h>
50 #include <xen/xenbus.h>
51 #include <xen/grant_table.h>
52 #include <xen/events.h>
55 #include <xen/interface/grant_table.h>
56 #include <xen/interface/io/vscsiif.h>
57 #include <xen/interface/io/protocols.h>
59 #include <asm/xen/hypervisor.h>
62 #define GRANT_INVALID_REF 0
64 #define VSCSIFRONT_OP_ADD_LUN 1
65 #define VSCSIFRONT_OP_DEL_LUN 2
66 #define VSCSIFRONT_OP_READD_LUN 3
69 #define VSCSIIF_DEFAULT_CMD_PER_LUN 10
70 #define VSCSIIF_MAX_TARGET 64
71 #define VSCSIIF_MAX_LUN 255
73 #define VSCSIIF_RING_SIZE __CONST_RING_SIZE(vscsiif, PAGE_SIZE)
74 #define VSCSIIF_MAX_REQS VSCSIIF_RING_SIZE
76 #define vscsiif_grants_sg(_sg) (PFN_UP((_sg) * \
77 sizeof(struct scsiif_request_segment)))
79 struct vscsifrnt_shadow {
80 /* command between backend and frontend */
84 unsigned int nr_grants; /* number of grants in gref[] */
85 struct scsiif_request_segment *sg; /* scatter/gather elements */
87 /* Do reset or abort function. */
88 wait_queue_head_t wq_reset; /* reset work queue */
89 int wait_reset; /* reset work queue condition */
90 int32_t rslt_reset; /* reset response status: */
91 /* SUCCESS or FAILED or: */
92 #define RSLT_RESET_WAITING 0
93 #define RSLT_RESET_ERR -1
95 /* Requested struct scsi_cmnd is stored from kernel. */
97 int gref[vscsiif_grants_sg(SG_ALL) + SG_ALL];
100 struct vscsifrnt_info {
101 struct xenbus_device *dev;
103 struct Scsi_Host *host;
109 grant_ref_t ring_ref;
110 struct vscsiif_front_ring ring;
111 struct vscsiif_response ring_rsp;
113 spinlock_t shadow_lock;
114 DECLARE_BITMAP(shadow_free_bitmap, VSCSIIF_MAX_REQS);
115 struct vscsifrnt_shadow *shadow[VSCSIIF_MAX_REQS];
117 /* Following items are protected by the host lock. */
118 wait_queue_head_t wq_sync;
119 wait_queue_head_t wq_pause;
120 unsigned int wait_ring_available:1;
121 unsigned int waiting_pause:1;
122 unsigned int pause:1;
125 char dev_state_path[64];
126 struct task_struct *curr;
129 static DEFINE_MUTEX(scsifront_mutex);
131 static void scsifront_wake_up(struct vscsifrnt_info *info)
133 info->wait_ring_available = 0;
134 wake_up(&info->wq_sync);
137 static int scsifront_get_rqid(struct vscsifrnt_info *info)
142 spin_lock_irqsave(&info->shadow_lock, flags);
144 free = find_first_bit(info->shadow_free_bitmap, VSCSIIF_MAX_REQS);
145 __clear_bit(free, info->shadow_free_bitmap);
147 spin_unlock_irqrestore(&info->shadow_lock, flags);
152 static int _scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id)
154 int empty = bitmap_empty(info->shadow_free_bitmap, VSCSIIF_MAX_REQS);
156 __set_bit(id, info->shadow_free_bitmap);
157 info->shadow[id] = NULL;
159 return empty || info->wait_ring_available;
162 static void scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id)
167 spin_lock_irqsave(&info->shadow_lock, flags);
168 kick = _scsifront_put_rqid(info, id);
169 spin_unlock_irqrestore(&info->shadow_lock, flags);
172 scsifront_wake_up(info);
175 static struct vscsiif_request *scsifront_pre_req(struct vscsifrnt_info *info)
177 struct vscsiif_front_ring *ring = &(info->ring);
178 struct vscsiif_request *ring_req;
181 id = scsifront_get_rqid(info); /* use id in response */
182 if (id >= VSCSIIF_MAX_REQS)
185 ring_req = RING_GET_REQUEST(&(info->ring), ring->req_prod_pvt);
187 ring->req_prod_pvt++;
189 ring_req->rqid = (uint16_t)id;
194 static void scsifront_do_request(struct vscsifrnt_info *info)
196 struct vscsiif_front_ring *ring = &(info->ring);
199 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(ring, notify);
201 notify_remote_via_irq(info->irq);
204 static void scsifront_gnttab_done(struct vscsifrnt_info *info, uint32_t id)
206 struct vscsifrnt_shadow *s = info->shadow[id];
209 if (s->sc->sc_data_direction == DMA_NONE)
212 for (i = 0; i < s->nr_grants; i++) {
213 if (unlikely(gnttab_query_foreign_access(s->gref[i]) != 0)) {
214 shost_printk(KERN_ALERT, info->host, KBUILD_MODNAME
215 "grant still in use by backend\n");
218 gnttab_end_foreign_access(s->gref[i], 0, 0UL);
224 static void scsifront_cdb_cmd_done(struct vscsifrnt_info *info,
225 struct vscsiif_response *ring_rsp)
227 struct scsi_cmnd *sc;
232 sc = info->shadow[id]->sc;
236 scsifront_gnttab_done(info, id);
237 scsifront_put_rqid(info, id);
239 sc->result = ring_rsp->rslt;
240 scsi_set_resid(sc, ring_rsp->residual_len);
242 sense_len = min_t(uint8_t, VSCSIIF_SENSE_BUFFERSIZE,
243 ring_rsp->sense_len);
246 memcpy(sc->sense_buffer, ring_rsp->sense_buffer, sense_len);
251 static void scsifront_sync_cmd_done(struct vscsifrnt_info *info,
252 struct vscsiif_response *ring_rsp)
254 uint16_t id = ring_rsp->rqid;
256 struct vscsifrnt_shadow *shadow = info->shadow[id];
259 spin_lock_irqsave(&info->shadow_lock, flags);
260 shadow->wait_reset = 1;
261 switch (shadow->rslt_reset) {
262 case RSLT_RESET_WAITING:
263 shadow->rslt_reset = ring_rsp->rslt;
266 kick = _scsifront_put_rqid(info, id);
267 spin_unlock_irqrestore(&info->shadow_lock, flags);
270 scsifront_wake_up(info);
273 shost_printk(KERN_ERR, info->host, KBUILD_MODNAME
274 "bad reset state %d, possibly leaking %u\n",
275 shadow->rslt_reset, id);
278 spin_unlock_irqrestore(&info->shadow_lock, flags);
280 wake_up(&shadow->wq_reset);
283 static void scsifront_do_response(struct vscsifrnt_info *info,
284 struct vscsiif_response *ring_rsp)
286 if (WARN(ring_rsp->rqid >= VSCSIIF_MAX_REQS ||
287 test_bit(ring_rsp->rqid, info->shadow_free_bitmap),
288 "illegal rqid %u returned by backend!\n", ring_rsp->rqid))
291 if (info->shadow[ring_rsp->rqid]->act == VSCSIIF_ACT_SCSI_CDB)
292 scsifront_cdb_cmd_done(info, ring_rsp);
294 scsifront_sync_cmd_done(info, ring_rsp);
297 static int scsifront_ring_drain(struct vscsifrnt_info *info)
299 struct vscsiif_response *ring_rsp;
303 rp = info->ring.sring->rsp_prod;
304 rmb(); /* ordering required respective to dom0 */
305 for (i = info->ring.rsp_cons; i != rp; i++) {
306 ring_rsp = RING_GET_RESPONSE(&info->ring, i);
307 scsifront_do_response(info, ring_rsp);
310 info->ring.rsp_cons = i;
312 if (i != info->ring.req_prod_pvt)
313 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
315 info->ring.sring->rsp_event = i + 1;
320 static int scsifront_cmd_done(struct vscsifrnt_info *info)
325 spin_lock_irqsave(info->host->host_lock, flags);
327 more_to_do = scsifront_ring_drain(info);
329 info->wait_ring_available = 0;
331 spin_unlock_irqrestore(info->host->host_lock, flags);
333 wake_up(&info->wq_sync);
338 static irqreturn_t scsifront_irq_fn(int irq, void *dev_id)
340 struct vscsifrnt_info *info = dev_id;
342 while (scsifront_cmd_done(info))
343 /* Yield point for this unbounded loop. */
349 static void scsifront_finish_all(struct vscsifrnt_info *info)
352 struct vscsiif_response resp;
354 scsifront_ring_drain(info);
356 for (i = 0; i < VSCSIIF_MAX_REQS; i++) {
357 if (test_bit(i, info->shadow_free_bitmap))
361 resp.rslt = DID_RESET << 16;
362 resp.residual_len = 0;
363 scsifront_do_response(info, &resp);
367 static int map_data_for_request(struct vscsifrnt_info *info,
368 struct scsi_cmnd *sc,
369 struct vscsiif_request *ring_req,
370 struct vscsifrnt_shadow *shadow)
372 grant_ref_t gref_head;
374 int err, ref, ref_cnt = 0;
375 int grant_ro = (sc->sc_data_direction == DMA_TO_DEVICE);
376 unsigned int i, off, len, bytes;
377 unsigned int data_len = scsi_bufflen(sc);
378 unsigned int data_grants = 0, seg_grants = 0;
379 struct scatterlist *sg;
380 struct scsiif_request_segment *seg;
382 ring_req->nr_segments = 0;
383 if (sc->sc_data_direction == DMA_NONE || !data_len)
386 scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i)
387 data_grants += PFN_UP(sg->offset + sg->length);
389 if (data_grants > VSCSIIF_SG_TABLESIZE) {
390 if (data_grants > info->host->sg_tablesize) {
391 shost_printk(KERN_ERR, info->host, KBUILD_MODNAME
392 "Unable to map request_buffer for command!\n");
395 seg_grants = vscsiif_grants_sg(data_grants);
396 shadow->sg = kcalloc(data_grants,
397 sizeof(struct scsiif_request_segment), GFP_ATOMIC);
401 seg = shadow->sg ? : ring_req->seg;
403 err = gnttab_alloc_grant_references(seg_grants + data_grants,
407 shost_printk(KERN_ERR, info->host, KBUILD_MODNAME
408 "gnttab_alloc_grant_references() error\n");
413 page = virt_to_page(seg);
414 off = (unsigned long)seg & ~PAGE_MASK;
415 len = sizeof(struct scsiif_request_segment) * data_grants;
417 bytes = min_t(unsigned int, len, PAGE_SIZE - off);
419 ref = gnttab_claim_grant_reference(&gref_head);
420 BUG_ON(ref == -ENOSPC);
422 gnttab_grant_foreign_access_ref(ref,
423 info->dev->otherend_id,
424 xen_page_to_gfn(page), 1);
425 shadow->gref[ref_cnt] = ref;
426 ring_req->seg[ref_cnt].gref = ref;
427 ring_req->seg[ref_cnt].offset = (uint16_t)off;
428 ring_req->seg[ref_cnt].length = (uint16_t)bytes;
435 BUG_ON(seg_grants < ref_cnt);
436 seg_grants = ref_cnt;
439 scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i) {
444 while (len > 0 && data_len > 0) {
446 * sg sends a scatterlist that is larger than
447 * the data_len it wants transferred for certain
450 bytes = min_t(unsigned int, len, PAGE_SIZE - off);
451 bytes = min(bytes, data_len);
453 ref = gnttab_claim_grant_reference(&gref_head);
454 BUG_ON(ref == -ENOSPC);
456 gnttab_grant_foreign_access_ref(ref,
457 info->dev->otherend_id,
458 xen_page_to_gfn(page),
461 shadow->gref[ref_cnt] = ref;
463 seg->offset = (uint16_t)off;
464 seg->length = (uint16_t)bytes;
476 ring_req->nr_segments = VSCSIIF_SG_GRANT | seg_grants;
478 ring_req->nr_segments = (uint8_t)ref_cnt;
479 shadow->nr_grants = ref_cnt;
484 static struct vscsiif_request *scsifront_command2ring(
485 struct vscsifrnt_info *info, struct scsi_cmnd *sc,
486 struct vscsifrnt_shadow *shadow)
488 struct vscsiif_request *ring_req;
490 memset(shadow, 0, sizeof(*shadow));
492 ring_req = scsifront_pre_req(info);
496 info->shadow[ring_req->rqid] = shadow;
497 shadow->rqid = ring_req->rqid;
499 ring_req->id = sc->device->id;
500 ring_req->lun = sc->device->lun;
501 ring_req->channel = sc->device->channel;
502 ring_req->cmd_len = sc->cmd_len;
504 BUG_ON(sc->cmd_len > VSCSIIF_MAX_COMMAND_SIZE);
506 memcpy(ring_req->cmnd, sc->cmnd, sc->cmd_len);
508 ring_req->sc_data_direction = (uint8_t)sc->sc_data_direction;
509 ring_req->timeout_per_command = sc->request->timeout / HZ;
514 static int scsifront_enter(struct vscsifrnt_info *info)
522 static void scsifront_return(struct vscsifrnt_info *info)
528 if (!info->waiting_pause)
531 info->waiting_pause = 0;
532 wake_up(&info->wq_pause);
535 static int scsifront_queuecommand(struct Scsi_Host *shost,
536 struct scsi_cmnd *sc)
538 struct vscsifrnt_info *info = shost_priv(shost);
539 struct vscsiif_request *ring_req;
540 struct vscsifrnt_shadow *shadow = scsi_cmd_priv(sc);
545 spin_lock_irqsave(shost->host_lock, flags);
546 if (scsifront_enter(info)) {
547 spin_unlock_irqrestore(shost->host_lock, flags);
548 return SCSI_MLQUEUE_HOST_BUSY;
550 if (RING_FULL(&info->ring))
553 ring_req = scsifront_command2ring(info, sc, shadow);
559 rqid = ring_req->rqid;
560 ring_req->act = VSCSIIF_ACT_SCSI_CDB;
563 shadow->act = VSCSIIF_ACT_SCSI_CDB;
565 err = map_data_for_request(info, sc, ring_req, shadow);
567 pr_debug("%s: err %d\n", __func__, err);
568 scsifront_put_rqid(info, rqid);
569 scsifront_return(info);
570 spin_unlock_irqrestore(shost->host_lock, flags);
572 return SCSI_MLQUEUE_HOST_BUSY;
573 sc->result = DID_ERROR << 16;
578 scsifront_do_request(info);
579 scsifront_return(info);
580 spin_unlock_irqrestore(shost->host_lock, flags);
585 scsifront_return(info);
586 spin_unlock_irqrestore(shost->host_lock, flags);
587 pr_debug("%s: busy\n", __func__);
588 return SCSI_MLQUEUE_HOST_BUSY;
592 * Any exception handling (reset or abort) must be forwarded to the backend.
593 * We have to wait until an answer is returned. This answer contains the
594 * result to be returned to the requestor.
596 static int scsifront_action_handler(struct scsi_cmnd *sc, uint8_t act)
598 struct Scsi_Host *host = sc->device->host;
599 struct vscsifrnt_info *info = shost_priv(host);
600 struct vscsifrnt_shadow *shadow, *s = scsi_cmd_priv(sc);
601 struct vscsiif_request *ring_req;
604 shadow = kmalloc(sizeof(*shadow), GFP_NOIO);
608 spin_lock_irq(host->host_lock);
611 if (!RING_FULL(&info->ring)) {
612 ring_req = scsifront_command2ring(info, sc, shadow);
616 if (err || info->pause) {
617 spin_unlock_irq(host->host_lock);
621 info->wait_ring_available = 1;
622 spin_unlock_irq(host->host_lock);
623 err = wait_event_interruptible(info->wq_sync,
624 !info->wait_ring_available);
625 spin_lock_irq(host->host_lock);
628 if (scsifront_enter(info)) {
629 spin_unlock_irq(host->host_lock);
634 ring_req->ref_rqid = s->rqid;
637 shadow->rslt_reset = RSLT_RESET_WAITING;
638 init_waitqueue_head(&shadow->wq_reset);
640 ring_req->nr_segments = 0;
642 scsifront_do_request(info);
644 spin_unlock_irq(host->host_lock);
645 err = wait_event_interruptible(shadow->wq_reset, shadow->wait_reset);
646 spin_lock_irq(host->host_lock);
649 err = shadow->rslt_reset;
650 scsifront_put_rqid(info, shadow->rqid);
653 spin_lock(&info->shadow_lock);
654 shadow->rslt_reset = RSLT_RESET_ERR;
655 spin_unlock(&info->shadow_lock);
659 scsifront_return(info);
660 spin_unlock_irq(host->host_lock);
664 static int scsifront_eh_abort_handler(struct scsi_cmnd *sc)
666 pr_debug("%s\n", __func__);
667 return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_ABORT);
670 static int scsifront_dev_reset_handler(struct scsi_cmnd *sc)
672 pr_debug("%s\n", __func__);
673 return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_RESET);
676 static int scsifront_sdev_configure(struct scsi_device *sdev)
678 struct vscsifrnt_info *info = shost_priv(sdev->host);
681 if (info && current == info->curr) {
682 err = xenbus_printf(XBT_NIL, info->dev->nodename,
683 info->dev_state_path, "%d", XenbusStateConnected);
685 xenbus_dev_error(info->dev, err,
686 "%s: writing dev_state_path", __func__);
694 static void scsifront_sdev_destroy(struct scsi_device *sdev)
696 struct vscsifrnt_info *info = shost_priv(sdev->host);
699 if (info && current == info->curr) {
700 err = xenbus_printf(XBT_NIL, info->dev->nodename,
701 info->dev_state_path, "%d", XenbusStateClosed);
703 xenbus_dev_error(info->dev, err,
704 "%s: writing dev_state_path", __func__);
708 static struct scsi_host_template scsifront_sht = {
709 .module = THIS_MODULE,
710 .name = "Xen SCSI frontend driver",
711 .queuecommand = scsifront_queuecommand,
712 .eh_abort_handler = scsifront_eh_abort_handler,
713 .eh_device_reset_handler = scsifront_dev_reset_handler,
714 .slave_configure = scsifront_sdev_configure,
715 .slave_destroy = scsifront_sdev_destroy,
716 .cmd_per_lun = VSCSIIF_DEFAULT_CMD_PER_LUN,
717 .can_queue = VSCSIIF_MAX_REQS,
719 .cmd_size = sizeof(struct vscsifrnt_shadow),
720 .sg_tablesize = VSCSIIF_SG_TABLESIZE,
721 .use_clustering = DISABLE_CLUSTERING,
722 .proc_name = "scsifront",
725 static int scsifront_alloc_ring(struct vscsifrnt_info *info)
727 struct xenbus_device *dev = info->dev;
728 struct vscsiif_sring *sring;
732 /***** Frontend to Backend ring start *****/
733 sring = (struct vscsiif_sring *)__get_free_page(GFP_KERNEL);
735 xenbus_dev_fatal(dev, err,
736 "fail to allocate shared ring (Front to Back)");
739 SHARED_RING_INIT(sring);
740 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
742 err = xenbus_grant_ring(dev, sring, 1, &gref);
744 free_page((unsigned long)sring);
745 xenbus_dev_fatal(dev, err,
746 "fail to grant shared ring (Front to Back)");
749 info->ring_ref = gref;
751 err = xenbus_alloc_evtchn(dev, &info->evtchn);
753 xenbus_dev_fatal(dev, err, "xenbus_alloc_evtchn");
757 err = bind_evtchn_to_irq(info->evtchn);
759 xenbus_dev_fatal(dev, err, "bind_evtchn_to_irq");
765 err = request_threaded_irq(info->irq, NULL, scsifront_irq_fn,
766 IRQF_ONESHOT, "scsifront", info);
768 xenbus_dev_fatal(dev, err, "request_threaded_irq");
776 unbind_from_irqhandler(info->irq, info);
778 gnttab_end_foreign_access(info->ring_ref, 0,
779 (unsigned long)info->ring.sring);
784 static void scsifront_free_ring(struct vscsifrnt_info *info)
786 unbind_from_irqhandler(info->irq, info);
787 gnttab_end_foreign_access(info->ring_ref, 0,
788 (unsigned long)info->ring.sring);
791 static int scsifront_init_ring(struct vscsifrnt_info *info)
793 struct xenbus_device *dev = info->dev;
794 struct xenbus_transaction xbt;
797 pr_debug("%s\n", __func__);
799 err = scsifront_alloc_ring(info);
802 pr_debug("%s: %u %u\n", __func__, info->ring_ref, info->evtchn);
805 err = xenbus_transaction_start(&xbt);
807 xenbus_dev_fatal(dev, err, "starting transaction");
809 err = xenbus_printf(xbt, dev->nodename, "ring-ref", "%u",
812 xenbus_dev_fatal(dev, err, "%s", "writing ring-ref");
816 err = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
820 xenbus_dev_fatal(dev, err, "%s", "writing event-channel");
824 err = xenbus_transaction_end(xbt, 0);
828 xenbus_dev_fatal(dev, err, "completing transaction");
835 xenbus_transaction_end(xbt, 1);
837 scsifront_free_ring(info);
843 static int scsifront_probe(struct xenbus_device *dev,
844 const struct xenbus_device_id *id)
846 struct vscsifrnt_info *info;
847 struct Scsi_Host *host;
849 char name[TASK_COMM_LEN];
851 host = scsi_host_alloc(&scsifront_sht, sizeof(*info));
853 xenbus_dev_fatal(dev, err, "fail to allocate scsi host");
856 info = (struct vscsifrnt_info *)host->hostdata;
858 dev_set_drvdata(&dev->dev, info);
861 bitmap_fill(info->shadow_free_bitmap, VSCSIIF_MAX_REQS);
863 err = scsifront_init_ring(info);
869 init_waitqueue_head(&info->wq_sync);
870 init_waitqueue_head(&info->wq_pause);
871 spin_lock_init(&info->shadow_lock);
873 snprintf(name, TASK_COMM_LEN, "vscsiif.%d", host->host_no);
875 host->max_id = VSCSIIF_MAX_TARGET;
876 host->max_channel = 0;
877 host->max_lun = VSCSIIF_MAX_LUN;
878 host->max_sectors = (host->sg_tablesize - 1) * PAGE_SIZE / 512;
879 host->max_cmd_len = VSCSIIF_MAX_COMMAND_SIZE;
881 err = scsi_add_host(host, &dev->dev);
883 dev_err(&dev->dev, "fail to add scsi host %d\n", err);
887 info->host_active = 1;
889 xenbus_switch_state(dev, XenbusStateInitialised);
894 scsifront_free_ring(info);
899 static int scsifront_resume(struct xenbus_device *dev)
901 struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
902 struct Scsi_Host *host = info->host;
905 spin_lock_irq(host->host_lock);
907 /* Finish all still pending commands. */
908 scsifront_finish_all(info);
910 spin_unlock_irq(host->host_lock);
912 /* Reconnect to dom0. */
913 scsifront_free_ring(info);
914 err = scsifront_init_ring(info);
916 dev_err(&dev->dev, "fail to resume %d\n", err);
921 xenbus_switch_state(dev, XenbusStateInitialised);
926 static int scsifront_suspend(struct xenbus_device *dev)
928 struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
929 struct Scsi_Host *host = info->host;
932 /* No new commands for the backend. */
933 spin_lock_irq(host->host_lock);
935 while (info->callers && !err) {
936 info->waiting_pause = 1;
937 info->wait_ring_available = 0;
938 spin_unlock_irq(host->host_lock);
939 wake_up(&info->wq_sync);
940 err = wait_event_interruptible(info->wq_pause,
941 !info->waiting_pause);
942 spin_lock_irq(host->host_lock);
944 spin_unlock_irq(host->host_lock);
948 static int scsifront_remove(struct xenbus_device *dev)
950 struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
952 pr_debug("%s: %s removed\n", __func__, dev->nodename);
954 mutex_lock(&scsifront_mutex);
955 if (info->host_active) {
956 /* Scsi_host not yet removed */
957 scsi_remove_host(info->host);
958 info->host_active = 0;
960 mutex_unlock(&scsifront_mutex);
962 scsifront_free_ring(info);
963 scsi_host_put(info->host);
968 static void scsifront_disconnect(struct vscsifrnt_info *info)
970 struct xenbus_device *dev = info->dev;
971 struct Scsi_Host *host = info->host;
973 pr_debug("%s: %s disconnect\n", __func__, dev->nodename);
976 * When this function is executed, all devices of
977 * Frontend have been deleted.
978 * Therefore, it need not block I/O before remove_host.
981 mutex_lock(&scsifront_mutex);
982 if (info->host_active) {
983 scsi_remove_host(host);
984 info->host_active = 0;
986 mutex_unlock(&scsifront_mutex);
988 xenbus_frontend_closed(dev);
991 static void scsifront_do_lun_hotplug(struct vscsifrnt_info *info, int op)
993 struct xenbus_device *dev = info->dev;
997 unsigned int dir_n = 0;
998 unsigned int device_state;
999 unsigned int hst, chn, tgt, lun;
1000 struct scsi_device *sdev;
1002 dir = xenbus_directory(XBT_NIL, dev->otherend, "vscsi-devs", &dir_n);
1006 /* mark current task as the one allowed to modify device states */
1008 info->curr = current;
1010 for (i = 0; i < dir_n; i++) {
1012 snprintf(str, sizeof(str), "vscsi-devs/%s/state", dir[i]);
1013 err = xenbus_scanf(XBT_NIL, dev->otherend, str, "%u",
1015 if (XENBUS_EXIST_ERR(err))
1018 /* virtual SCSI device */
1019 snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", dir[i]);
1020 err = xenbus_scanf(XBT_NIL, dev->otherend, str,
1021 "%u:%u:%u:%u", &hst, &chn, &tgt, &lun);
1022 if (XENBUS_EXIST_ERR(err))
1026 * Front device state path, used in slave_configure called
1027 * on successfull scsi_add_device, and in slave_destroy called
1028 * on remove of a device.
1030 snprintf(info->dev_state_path, sizeof(info->dev_state_path),
1031 "vscsi-devs/%s/state", dir[i]);
1034 case VSCSIFRONT_OP_ADD_LUN:
1035 if (device_state != XenbusStateInitialised)
1038 if (scsi_add_device(info->host, chn, tgt, lun)) {
1039 dev_err(&dev->dev, "scsi_add_device\n");
1040 err = xenbus_printf(XBT_NIL, dev->nodename,
1041 info->dev_state_path,
1042 "%d", XenbusStateClosed);
1044 xenbus_dev_error(dev, err,
1045 "%s: writing dev_state_path", __func__);
1048 case VSCSIFRONT_OP_DEL_LUN:
1049 if (device_state != XenbusStateClosing)
1052 sdev = scsi_device_lookup(info->host, chn, tgt, lun);
1054 scsi_remove_device(sdev);
1055 scsi_device_put(sdev);
1058 case VSCSIFRONT_OP_READD_LUN:
1059 if (device_state == XenbusStateConnected) {
1060 err = xenbus_printf(XBT_NIL, dev->nodename,
1061 info->dev_state_path,
1062 "%d", XenbusStateConnected);
1064 xenbus_dev_error(dev, err,
1065 "%s: writing dev_state_path", __func__);
1078 static void scsifront_read_backend_params(struct xenbus_device *dev,
1079 struct vscsifrnt_info *info)
1081 unsigned int sg_grant, nr_segs;
1083 struct Scsi_Host *host = info->host;
1085 ret = xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg-grant", "%u",
1089 nr_segs = min_t(unsigned int, sg_grant, SG_ALL);
1090 nr_segs = max_t(unsigned int, nr_segs, VSCSIIF_SG_TABLESIZE);
1091 nr_segs = min_t(unsigned int, nr_segs,
1092 VSCSIIF_SG_TABLESIZE * PAGE_SIZE /
1093 sizeof(struct scsiif_request_segment));
1095 if (!info->pause && sg_grant)
1096 dev_info(&dev->dev, "using up to %d SG entries\n", nr_segs);
1097 else if (info->pause && nr_segs < host->sg_tablesize)
1099 "SG entries decreased from %d to %u - device may not work properly anymore\n",
1100 host->sg_tablesize, nr_segs);
1102 host->sg_tablesize = nr_segs;
1103 host->max_sectors = (nr_segs - 1) * PAGE_SIZE / 512;
1106 static void scsifront_backend_changed(struct xenbus_device *dev,
1107 enum xenbus_state backend_state)
1109 struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
1111 pr_debug("%s: %p %u %u\n", __func__, dev, dev->state, backend_state);
1113 switch (backend_state) {
1114 case XenbusStateUnknown:
1115 case XenbusStateInitialising:
1116 case XenbusStateInitWait:
1117 case XenbusStateInitialised:
1120 case XenbusStateConnected:
1121 scsifront_read_backend_params(dev, info);
1124 scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_READD_LUN);
1125 xenbus_switch_state(dev, XenbusStateConnected);
1130 if (xenbus_read_driver_state(dev->nodename) ==
1131 XenbusStateInitialised)
1132 scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN);
1134 if (dev->state != XenbusStateConnected)
1135 xenbus_switch_state(dev, XenbusStateConnected);
1138 case XenbusStateClosed:
1139 if (dev->state == XenbusStateClosed)
1141 /* Missed the backend's Closing state -- fallthrough */
1142 case XenbusStateClosing:
1143 scsifront_disconnect(info);
1146 case XenbusStateReconfiguring:
1147 scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_DEL_LUN);
1148 xenbus_switch_state(dev, XenbusStateReconfiguring);
1151 case XenbusStateReconfigured:
1152 scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN);
1153 xenbus_switch_state(dev, XenbusStateConnected);
1158 static const struct xenbus_device_id scsifront_ids[] = {
1163 static struct xenbus_driver scsifront_driver = {
1164 .ids = scsifront_ids,
1165 .probe = scsifront_probe,
1166 .remove = scsifront_remove,
1167 .resume = scsifront_resume,
1168 .suspend = scsifront_suspend,
1169 .otherend_changed = scsifront_backend_changed,
1172 static int __init scsifront_init(void)
1177 return xenbus_register_frontend(&scsifront_driver);
1179 module_init(scsifront_init);
1181 static void __exit scsifront_exit(void)
1183 xenbus_unregister_driver(&scsifront_driver);
1185 module_exit(scsifront_exit);
1187 MODULE_DESCRIPTION("Xen SCSI frontend driver");
1188 MODULE_LICENSE("GPL");
1189 MODULE_ALIAS("xen:vscsi");
1190 MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");