4 * XenLinux virtual block device driver.
6 * Copyright (c) 2003-2004, Keir Fraser & Steve Hand
7 * Modifications by Mark A. Williamson are (c) Intel Research Cambridge
8 * Copyright (c) 2004, Christian Limpach
9 * Copyright (c) 2004, Andrew Warfield
10 * Copyright (c) 2005, Christopher Clark
11 * Copyright (c) 2005, XenSource Ltd
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License version 2
15 * as published by the Free Software Foundation; or, when distributed
16 * separately from the Linux kernel or incorporated into other
17 * software packages, subject to the following license:
19 * Permission is hereby granted, free of charge, to any person obtaining a copy
20 * of this source file (the "Software"), to deal in the Software without
21 * restriction, including without limitation the rights to use, copy, modify,
22 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
23 * and to permit persons to whom the Software is furnished to do so, subject to
24 * the following conditions:
26 * The above copyright notice and this permission notice shall be included in
27 * all copies or substantial portions of the Software.
29 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
30 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
31 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
32 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
33 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
34 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
38 #include <linux/interrupt.h>
39 #include <linux/blkdev.h>
40 #include <linux/hdreg.h>
41 #include <linux/cdrom.h>
42 #include <linux/module.h>
43 #include <linux/slab.h>
44 #include <linux/smp_lock.h>
45 #include <linux/scatterlist.h>
48 #include <xen/xenbus.h>
49 #include <xen/grant_table.h>
50 #include <xen/events.h>
53 #include <xen/interface/grant_table.h>
54 #include <xen/interface/io/blkif.h>
55 #include <xen/interface/io/protocols.h>
57 #include <asm/xen/hypervisor.h>
60 BLKIF_STATE_DISCONNECTED,
61 BLKIF_STATE_CONNECTED,
62 BLKIF_STATE_SUSPENDED,
66 struct blkif_request req;
67 unsigned long request;
68 unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
71 static const struct block_device_operations xlvbd_block_fops;
73 #define BLK_RING_SIZE __RING_SIZE((struct blkif_sring *)0, PAGE_SIZE)
76 * We have one of these per vbd, whether ide, scsi or 'other'. They
77 * hang in private_data off the gendisk structure. We may end up
78 * putting all kinds of interesting stuff here :-)
83 struct xenbus_device *xbdev;
87 enum blkif_state connected;
89 struct blkif_front_ring ring;
90 struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
91 unsigned int evtchn, irq;
92 struct request_queue *rq;
93 struct work_struct work;
94 struct gnttab_free_callback callback;
95 struct blk_shadow shadow[BLK_RING_SIZE];
96 unsigned long shadow_free;
101 static DEFINE_SPINLOCK(blkif_io_lock);
103 static unsigned int nr_minors;
104 static unsigned long *minors;
105 static DEFINE_SPINLOCK(minor_lock);
107 #define MAXIMUM_OUTSTANDING_BLOCK_REQS \
108 (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
109 #define GRANT_INVALID_REF 0
111 #define PARTS_PER_DISK 16
112 #define PARTS_PER_EXT_DISK 256
114 #define BLKIF_MAJOR(dev) ((dev)>>8)
115 #define BLKIF_MINOR(dev) ((dev) & 0xff)
118 #define EXTENDED (1<<EXT_SHIFT)
119 #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
120 #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
122 #define DEV_NAME "xvd" /* name in /dev */
124 static int get_id_from_freelist(struct blkfront_info *info)
126 unsigned long free = info->shadow_free;
127 BUG_ON(free >= BLK_RING_SIZE);
128 info->shadow_free = info->shadow[free].req.id;
129 info->shadow[free].req.id = 0x0fffffee; /* debug */
133 static void add_id_to_freelist(struct blkfront_info *info,
136 info->shadow[id].req.id = info->shadow_free;
137 info->shadow[id].request = 0;
138 info->shadow_free = id;
141 static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
143 unsigned int end = minor + nr;
146 if (end > nr_minors) {
147 unsigned long *bitmap, *old;
149 bitmap = kzalloc(BITS_TO_LONGS(end) * sizeof(*bitmap),
154 spin_lock(&minor_lock);
155 if (end > nr_minors) {
157 memcpy(bitmap, minors,
158 BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
160 nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
163 spin_unlock(&minor_lock);
167 spin_lock(&minor_lock);
168 if (find_next_bit(minors, end, minor) >= end) {
169 for (; minor < end; ++minor)
170 __set_bit(minor, minors);
174 spin_unlock(&minor_lock);
179 static void xlbd_release_minors(unsigned int minor, unsigned int nr)
181 unsigned int end = minor + nr;
183 BUG_ON(end > nr_minors);
184 spin_lock(&minor_lock);
185 for (; minor < end; ++minor)
186 __clear_bit(minor, minors);
187 spin_unlock(&minor_lock);
190 static void blkif_restart_queue_callback(void *arg)
192 struct blkfront_info *info = (struct blkfront_info *)arg;
193 schedule_work(&info->work);
196 static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
198 /* We don't have real geometry info, but let's at least return
199 values consistent with the size of the device */
200 sector_t nsect = get_capacity(bd->bd_disk);
201 sector_t cylinders = nsect;
205 sector_div(cylinders, hg->heads * hg->sectors);
206 hg->cylinders = cylinders;
207 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
208 hg->cylinders = 0xffff;
212 static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
213 unsigned command, unsigned long argument)
215 struct blkfront_info *info = bdev->bd_disk->private_data;
218 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
219 command, (long)argument);
222 case CDROMMULTISESSION:
223 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
224 for (i = 0; i < sizeof(struct cdrom_multisession); i++)
225 if (put_user(0, (char __user *)(argument + i)))
229 case CDROM_GET_CAPABILITY: {
230 struct gendisk *gd = info->gd;
231 if (gd->flags & GENHD_FL_CD)
237 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
239 return -EINVAL; /* same return as native Linux */
246 * blkif_queue_request
250 * id: for guest use only.
251 * operation: BLKIF_OP_{READ,WRITE,PROBE}
252 * buffer: buffer to read/write into. this should be a
253 * virtual address in the guest os.
255 static int blkif_queue_request(struct request *req)
257 struct blkfront_info *info = req->rq_disk->private_data;
258 unsigned long buffer_mfn;
259 struct blkif_request *ring_req;
261 unsigned int fsect, lsect;
263 grant_ref_t gref_head;
264 struct scatterlist *sg;
266 if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
269 if (gnttab_alloc_grant_references(
270 BLKIF_MAX_SEGMENTS_PER_REQUEST, &gref_head) < 0) {
271 gnttab_request_free_callback(
273 blkif_restart_queue_callback,
275 BLKIF_MAX_SEGMENTS_PER_REQUEST);
279 /* Fill out a communications ring structure. */
280 ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
281 id = get_id_from_freelist(info);
282 info->shadow[id].request = (unsigned long)req;
285 ring_req->sector_number = (blkif_sector_t)blk_rq_pos(req);
286 ring_req->handle = info->handle;
288 ring_req->operation = rq_data_dir(req) ?
289 BLKIF_OP_WRITE : BLKIF_OP_READ;
290 if (req->cmd_flags & REQ_HARDBARRIER)
291 ring_req->operation = BLKIF_OP_WRITE_BARRIER;
293 ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
294 BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
296 for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
297 buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
298 fsect = sg->offset >> 9;
299 lsect = fsect + (sg->length >> 9) - 1;
300 /* install a grant reference. */
301 ref = gnttab_claim_grant_reference(&gref_head);
302 BUG_ON(ref == -ENOSPC);
304 gnttab_grant_foreign_access_ref(
306 info->xbdev->otherend_id,
310 info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
312 (struct blkif_request_segment) {
315 .last_sect = lsect };
318 info->ring.req_prod_pvt++;
320 /* Keep a private copy so we can reissue requests when recovering. */
321 info->shadow[id].req = *ring_req;
323 gnttab_free_grant_references(gref_head);
329 static inline void flush_requests(struct blkfront_info *info)
333 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify);
336 notify_remote_via_irq(info->irq);
341 * read a block; request is in a request queue
343 static void do_blkif_request(struct request_queue *rq)
345 struct blkfront_info *info = NULL;
349 pr_debug("Entered do_blkif_request\n");
353 while ((req = blk_peek_request(rq)) != NULL) {
354 info = req->rq_disk->private_data;
356 if (RING_FULL(&info->ring))
359 blk_start_request(req);
361 if (req->cmd_type != REQ_TYPE_FS) {
362 __blk_end_request_all(req, -EIO);
366 pr_debug("do_blk_req %p: cmd %p, sec %lx, "
367 "(%u/%u) buffer:%p [%s]\n",
368 req, req->cmd, (unsigned long)blk_rq_pos(req),
369 blk_rq_cur_sectors(req), blk_rq_sectors(req),
370 req->buffer, rq_data_dir(req) ? "write" : "read");
372 if (blkif_queue_request(req)) {
373 blk_requeue_request(rq, req);
375 /* Avoid pointless unplugs. */
384 flush_requests(info);
387 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
389 struct request_queue *rq;
391 rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
395 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
397 /* Hard sector size and max sectors impersonate the equiv. hardware. */
398 blk_queue_logical_block_size(rq, sector_size);
399 blk_queue_max_hw_sectors(rq, 512);
401 /* Each segment in a request is up to an aligned page in size. */
402 blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
403 blk_queue_max_segment_size(rq, PAGE_SIZE);
405 /* Ensure a merged request will fit in a single I/O ring slot. */
406 blk_queue_max_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST);
408 /* Make sure buffer addresses are sector-aligned. */
409 blk_queue_dma_alignment(rq, 511);
411 /* Make sure we don't use bounce buffers. */
412 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
420 static int xlvbd_barrier(struct blkfront_info *info)
424 err = blk_queue_ordered(info->rq,
425 info->feature_barrier ? QUEUE_ORDERED_DRAIN : QUEUE_ORDERED_NONE);
430 printk(KERN_INFO "blkfront: %s: barriers %s\n",
432 info->feature_barrier ? "enabled" : "disabled");
437 static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
438 struct blkfront_info *info,
439 u16 vdisk_info, u16 sector_size)
448 BUG_ON(info->gd != NULL);
449 BUG_ON(info->rq != NULL);
451 if ((info->vdevice>>EXT_SHIFT) > 1) {
452 /* this is above the extended range; something is wrong */
453 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice);
457 if (!VDEV_IS_EXTENDED(info->vdevice)) {
458 minor = BLKIF_MINOR(info->vdevice);
459 nr_parts = PARTS_PER_DISK;
461 minor = BLKIF_MINOR_EXT(info->vdevice);
462 nr_parts = PARTS_PER_EXT_DISK;
465 if ((minor % nr_parts) == 0)
466 nr_minors = nr_parts;
468 err = xlbd_reserve_minors(minor, nr_minors);
473 gd = alloc_disk(nr_minors);
477 offset = minor / nr_parts;
481 sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset);
483 sprintf(gd->disk_name, "%s%c%c", DEV_NAME,
484 'a' + ((offset / 26)-1), 'a' + (offset % 26));
487 sprintf(gd->disk_name, "%s%c%d", DEV_NAME,
489 minor & (nr_parts - 1));
491 sprintf(gd->disk_name, "%s%c%c%d", DEV_NAME,
492 'a' + ((offset / 26) - 1),
494 minor & (nr_parts - 1));
497 gd->major = XENVBD_MAJOR;
498 gd->first_minor = minor;
499 gd->fops = &xlvbd_block_fops;
500 gd->private_data = info;
501 gd->driverfs_dev = &(info->xbdev->dev);
502 set_capacity(gd, capacity);
504 if (xlvbd_init_blk_queue(gd, sector_size)) {
509 info->rq = gd->queue;
512 if (info->feature_barrier)
515 if (vdisk_info & VDISK_READONLY)
518 if (vdisk_info & VDISK_REMOVABLE)
519 gd->flags |= GENHD_FL_REMOVABLE;
521 if (vdisk_info & VDISK_CDROM)
522 gd->flags |= GENHD_FL_CD;
527 xlbd_release_minors(minor, nr_minors);
532 static void xlvbd_release_gendisk(struct blkfront_info *info)
534 unsigned int minor, nr_minors;
537 if (info->rq == NULL)
540 spin_lock_irqsave(&blkif_io_lock, flags);
542 /* No more blkif_request(). */
543 blk_stop_queue(info->rq);
545 /* No more gnttab callback work. */
546 gnttab_cancel_free_callback(&info->callback);
547 spin_unlock_irqrestore(&blkif_io_lock, flags);
549 /* Flush gnttab callback work. Must be done with no locks held. */
550 flush_scheduled_work();
552 del_gendisk(info->gd);
554 minor = info->gd->first_minor;
555 nr_minors = info->gd->minors;
556 xlbd_release_minors(minor, nr_minors);
558 blk_cleanup_queue(info->rq);
565 static void kick_pending_request_queues(struct blkfront_info *info)
567 if (!RING_FULL(&info->ring)) {
568 /* Re-enable calldowns. */
569 blk_start_queue(info->rq);
570 /* Kick things off immediately. */
571 do_blkif_request(info->rq);
575 static void blkif_restart_queue(struct work_struct *work)
577 struct blkfront_info *info = container_of(work, struct blkfront_info, work);
579 spin_lock_irq(&blkif_io_lock);
580 if (info->connected == BLKIF_STATE_CONNECTED)
581 kick_pending_request_queues(info);
582 spin_unlock_irq(&blkif_io_lock);
585 static void blkif_free(struct blkfront_info *info, int suspend)
587 /* Prevent new requests being issued until we fix things up. */
588 spin_lock_irq(&blkif_io_lock);
589 info->connected = suspend ?
590 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
591 /* No more blkif_request(). */
593 blk_stop_queue(info->rq);
594 /* No more gnttab callback work. */
595 gnttab_cancel_free_callback(&info->callback);
596 spin_unlock_irq(&blkif_io_lock);
598 /* Flush gnttab callback work. Must be done with no locks held. */
599 flush_scheduled_work();
601 /* Free resources associated with old device channel. */
602 if (info->ring_ref != GRANT_INVALID_REF) {
603 gnttab_end_foreign_access(info->ring_ref, 0,
604 (unsigned long)info->ring.sring);
605 info->ring_ref = GRANT_INVALID_REF;
606 info->ring.sring = NULL;
609 unbind_from_irqhandler(info->irq, info);
610 info->evtchn = info->irq = 0;
614 static void blkif_completion(struct blk_shadow *s)
617 for (i = 0; i < s->req.nr_segments; i++)
618 gnttab_end_foreign_access(s->req.seg[i].gref, 0, 0UL);
621 static irqreturn_t blkif_interrupt(int irq, void *dev_id)
624 struct blkif_response *bret;
627 struct blkfront_info *info = (struct blkfront_info *)dev_id;
630 spin_lock_irqsave(&blkif_io_lock, flags);
632 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
633 spin_unlock_irqrestore(&blkif_io_lock, flags);
638 rp = info->ring.sring->rsp_prod;
639 rmb(); /* Ensure we see queued responses up to 'rp'. */
641 for (i = info->ring.rsp_cons; i != rp; i++) {
644 bret = RING_GET_RESPONSE(&info->ring, i);
646 req = (struct request *)info->shadow[id].request;
648 blkif_completion(&info->shadow[id]);
650 add_id_to_freelist(info, id);
652 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
653 switch (bret->operation) {
654 case BLKIF_OP_WRITE_BARRIER:
655 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
656 printk(KERN_WARNING "blkfront: %s: write barrier op failed\n",
657 info->gd->disk_name);
659 info->feature_barrier = 0;
665 if (unlikely(bret->status != BLKIF_RSP_OKAY))
666 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
667 "request: %x\n", bret->status);
669 __blk_end_request_all(req, error);
676 info->ring.rsp_cons = i;
678 if (i != info->ring.req_prod_pvt) {
680 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
684 info->ring.sring->rsp_event = i + 1;
686 kick_pending_request_queues(info);
688 spin_unlock_irqrestore(&blkif_io_lock, flags);
694 static int setup_blkring(struct xenbus_device *dev,
695 struct blkfront_info *info)
697 struct blkif_sring *sring;
700 info->ring_ref = GRANT_INVALID_REF;
702 sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
704 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
707 SHARED_RING_INIT(sring);
708 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
710 sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
712 err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
714 free_page((unsigned long)sring);
715 info->ring.sring = NULL;
718 info->ring_ref = err;
720 err = xenbus_alloc_evtchn(dev, &info->evtchn);
724 err = bind_evtchn_to_irqhandler(info->evtchn,
726 IRQF_SAMPLE_RANDOM, "blkif", info);
728 xenbus_dev_fatal(dev, err,
729 "bind_evtchn_to_irqhandler failed");
741 /* Common code used when first setting up, and when resuming. */
742 static int talk_to_blkback(struct xenbus_device *dev,
743 struct blkfront_info *info)
745 const char *message = NULL;
746 struct xenbus_transaction xbt;
749 /* Create shared ring, alloc event channel. */
750 err = setup_blkring(dev, info);
755 err = xenbus_transaction_start(&xbt);
757 xenbus_dev_fatal(dev, err, "starting transaction");
758 goto destroy_blkring;
761 err = xenbus_printf(xbt, dev->nodename,
762 "ring-ref", "%u", info->ring_ref);
764 message = "writing ring-ref";
765 goto abort_transaction;
767 err = xenbus_printf(xbt, dev->nodename,
768 "event-channel", "%u", info->evtchn);
770 message = "writing event-channel";
771 goto abort_transaction;
773 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
774 XEN_IO_PROTO_ABI_NATIVE);
776 message = "writing protocol";
777 goto abort_transaction;
780 err = xenbus_transaction_end(xbt, 0);
784 xenbus_dev_fatal(dev, err, "completing transaction");
785 goto destroy_blkring;
788 xenbus_switch_state(dev, XenbusStateInitialised);
793 xenbus_transaction_end(xbt, 1);
795 xenbus_dev_fatal(dev, err, "%s", message);
803 * Entry point to this code when a new device is created. Allocate the basic
804 * structures and the ring buffer for communication with the backend, and
805 * inform the backend of the appropriate details for those. Switch to
808 static int blkfront_probe(struct xenbus_device *dev,
809 const struct xenbus_device_id *id)
812 struct blkfront_info *info;
814 /* FIXME: Use dynamic device id if this is not set. */
815 err = xenbus_scanf(XBT_NIL, dev->nodename,
816 "virtual-device", "%i", &vdevice);
818 /* go looking in the extended area instead */
819 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext",
822 xenbus_dev_fatal(dev, err, "reading virtual-device");
827 info = kzalloc(sizeof(*info), GFP_KERNEL);
829 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
833 mutex_init(&info->mutex);
835 info->vdevice = vdevice;
836 info->connected = BLKIF_STATE_DISCONNECTED;
837 INIT_WORK(&info->work, blkif_restart_queue);
839 for (i = 0; i < BLK_RING_SIZE; i++)
840 info->shadow[i].req.id = i+1;
841 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
843 /* Front end dir is a number, which is used as the id. */
844 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
845 dev_set_drvdata(&dev->dev, info);
847 err = talk_to_blkback(dev, info);
850 dev_set_drvdata(&dev->dev, NULL);
858 static int blkif_recover(struct blkfront_info *info)
861 struct blkif_request *req;
862 struct blk_shadow *copy;
865 /* Stage 1: Make a safe copy of the shadow state. */
866 copy = kmalloc(sizeof(info->shadow),
867 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
870 memcpy(copy, info->shadow, sizeof(info->shadow));
872 /* Stage 2: Set up free list. */
873 memset(&info->shadow, 0, sizeof(info->shadow));
874 for (i = 0; i < BLK_RING_SIZE; i++)
875 info->shadow[i].req.id = i+1;
876 info->shadow_free = info->ring.req_prod_pvt;
877 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
879 /* Stage 3: Find pending requests and requeue them. */
880 for (i = 0; i < BLK_RING_SIZE; i++) {
882 if (copy[i].request == 0)
885 /* Grab a request slot and copy shadow state into it. */
886 req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
889 /* We get a new request id, and must reset the shadow state. */
890 req->id = get_id_from_freelist(info);
891 memcpy(&info->shadow[req->id], ©[i], sizeof(copy[i]));
893 /* Rewrite any grant references invalidated by susp/resume. */
894 for (j = 0; j < req->nr_segments; j++)
895 gnttab_grant_foreign_access_ref(
897 info->xbdev->otherend_id,
898 pfn_to_mfn(info->shadow[req->id].frame[j]),
901 info->shadow[req->id].request));
902 info->shadow[req->id].req = *req;
904 info->ring.req_prod_pvt++;
909 xenbus_switch_state(info->xbdev, XenbusStateConnected);
911 spin_lock_irq(&blkif_io_lock);
913 /* Now safe for us to use the shared ring */
914 info->connected = BLKIF_STATE_CONNECTED;
916 /* Send off requeued requests */
917 flush_requests(info);
919 /* Kick any other new requests queued since we resumed */
920 kick_pending_request_queues(info);
922 spin_unlock_irq(&blkif_io_lock);
928 * We are reconnecting to the backend, due to a suspend/resume, or a backend
929 * driver restart. We tear down our blkif structure and recreate it, but
930 * leave the device-layer structures intact so that this is transparent to the
931 * rest of the kernel.
933 static int blkfront_resume(struct xenbus_device *dev)
935 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
938 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
940 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
942 err = talk_to_blkback(dev, info);
943 if (info->connected == BLKIF_STATE_SUSPENDED && !err)
944 err = blkif_recover(info);
950 blkfront_closing(struct blkfront_info *info)
952 struct xenbus_device *xbdev = info->xbdev;
953 struct block_device *bdev = NULL;
955 mutex_lock(&info->mutex);
957 if (xbdev->state == XenbusStateClosing) {
958 mutex_unlock(&info->mutex);
963 bdev = bdget_disk(info->gd, 0);
965 mutex_unlock(&info->mutex);
968 xenbus_frontend_closed(xbdev);
972 mutex_lock(&bdev->bd_mutex);
974 if (bdev->bd_openers) {
975 xenbus_dev_error(xbdev, -EBUSY,
976 "Device in use; refusing to close");
977 xenbus_switch_state(xbdev, XenbusStateClosing);
979 xlvbd_release_gendisk(info);
980 xenbus_frontend_closed(xbdev);
983 mutex_unlock(&bdev->bd_mutex);
988 * Invoked when the backend is finally 'ready' (and has told produced
989 * the details about the physical device - #sectors, size, etc).
991 static void blkfront_connect(struct blkfront_info *info)
993 unsigned long long sectors;
994 unsigned long sector_size;
998 switch (info->connected) {
999 case BLKIF_STATE_CONNECTED:
1001 * Potentially, the back-end may be signalling
1002 * a capacity change; update the capacity.
1004 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1005 "sectors", "%Lu", §ors);
1006 if (XENBUS_EXIST_ERR(err))
1008 printk(KERN_INFO "Setting capacity to %Lu\n",
1010 set_capacity(info->gd, sectors);
1011 revalidate_disk(info->gd);
1014 case BLKIF_STATE_SUSPENDED:
1021 dev_dbg(&info->xbdev->dev, "%s:%s.\n",
1022 __func__, info->xbdev->otherend);
1024 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1025 "sectors", "%llu", §ors,
1026 "info", "%u", &binfo,
1027 "sector-size", "%lu", §or_size,
1030 xenbus_dev_fatal(info->xbdev, err,
1031 "reading backend fields at %s",
1032 info->xbdev->otherend);
1036 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1037 "feature-barrier", "%lu", &info->feature_barrier,
1040 info->feature_barrier = 0;
1042 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
1044 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
1045 info->xbdev->otherend);
1049 xenbus_switch_state(info->xbdev, XenbusStateConnected);
1051 /* Kick pending requests. */
1052 spin_lock_irq(&blkif_io_lock);
1053 info->connected = BLKIF_STATE_CONNECTED;
1054 kick_pending_request_queues(info);
1055 spin_unlock_irq(&blkif_io_lock);
1063 * Callback received when the backend's state changes.
1065 static void blkback_changed(struct xenbus_device *dev,
1066 enum xenbus_state backend_state)
1068 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1070 dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state);
1072 switch (backend_state) {
1073 case XenbusStateInitialising:
1074 case XenbusStateInitWait:
1075 case XenbusStateInitialised:
1076 case XenbusStateUnknown:
1077 case XenbusStateClosed:
1080 case XenbusStateConnected:
1081 blkfront_connect(info);
1084 case XenbusStateClosing:
1085 blkfront_closing(info);
1090 static int blkfront_remove(struct xenbus_device *xbdev)
1092 struct blkfront_info *info = dev_get_drvdata(&xbdev->dev);
1093 struct block_device *bdev = NULL;
1094 struct gendisk *disk;
1096 dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
1098 blkif_free(info, 0);
1100 mutex_lock(&info->mutex);
1104 bdev = bdget_disk(disk, 0);
1107 mutex_unlock(&info->mutex);
1115 * The xbdev was removed before we reached the Closed
1116 * state. See if it's safe to remove the disk. If the bdev
1117 * isn't closed yet, we let release take care of it.
1120 mutex_lock(&bdev->bd_mutex);
1121 info = disk->private_data;
1123 dev_warn(disk_to_dev(disk),
1124 "%s was hot-unplugged, %d stale handles\n",
1125 xbdev->nodename, bdev->bd_openers);
1127 if (info && !bdev->bd_openers) {
1128 xlvbd_release_gendisk(info);
1129 disk->private_data = NULL;
1133 mutex_unlock(&bdev->bd_mutex);
1139 static int blkfront_is_ready(struct xenbus_device *dev)
1141 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1143 return info->is_ready && info->xbdev;
1146 static int blkif_open(struct block_device *bdev, fmode_t mode)
1148 struct gendisk *disk = bdev->bd_disk;
1149 struct blkfront_info *info;
1154 info = disk->private_data;
1161 mutex_lock(&info->mutex);
1164 /* xbdev is closed */
1167 mutex_unlock(&info->mutex);
1174 static int blkif_release(struct gendisk *disk, fmode_t mode)
1176 struct blkfront_info *info = disk->private_data;
1177 struct block_device *bdev;
1178 struct xenbus_device *xbdev;
1182 bdev = bdget_disk(disk, 0);
1185 if (bdev->bd_openers)
1189 * Check if we have been instructed to close. We will have
1190 * deferred this request, because the bdev was still open.
1193 mutex_lock(&info->mutex);
1194 xbdev = info->xbdev;
1196 if (xbdev && xbdev->state == XenbusStateClosing) {
1197 /* pending switch to state closed */
1198 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
1199 xlvbd_release_gendisk(info);
1200 xenbus_frontend_closed(info->xbdev);
1203 mutex_unlock(&info->mutex);
1206 /* sudden device removal */
1207 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
1208 xlvbd_release_gendisk(info);
1209 disk->private_data = NULL;
1217 static const struct block_device_operations xlvbd_block_fops =
1219 .owner = THIS_MODULE,
1221 .release = blkif_release,
1222 .getgeo = blkif_getgeo,
1223 .ioctl = blkif_ioctl,
1227 static const struct xenbus_device_id blkfront_ids[] = {
1232 static struct xenbus_driver blkfront = {
1234 .owner = THIS_MODULE,
1235 .ids = blkfront_ids,
1236 .probe = blkfront_probe,
1237 .remove = blkfront_remove,
1238 .resume = blkfront_resume,
1239 .otherend_changed = blkback_changed,
1240 .is_ready = blkfront_is_ready,
1243 static int __init xlblk_init(void)
1248 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
1249 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
1250 XENVBD_MAJOR, DEV_NAME);
1254 return xenbus_register_frontend(&blkfront);
1256 module_init(xlblk_init);
1259 static void __exit xlblk_exit(void)
1261 return xenbus_unregister_driver(&blkfront);
1263 module_exit(xlblk_exit);
1265 MODULE_DESCRIPTION("Xen virtual block device frontend");
1266 MODULE_LICENSE("GPL");
1267 MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
1268 MODULE_ALIAS("xen:vbd");
1269 MODULE_ALIAS("xenblk");