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>
52 #include <xen/platform_pci.h>
54 #include <xen/interface/grant_table.h>
55 #include <xen/interface/io/blkif.h>
56 #include <xen/interface/io/protocols.h>
58 #include <asm/xen/hypervisor.h>
61 BLKIF_STATE_DISCONNECTED,
62 BLKIF_STATE_CONNECTED,
63 BLKIF_STATE_SUSPENDED,
67 struct blkif_request req;
68 unsigned long request;
69 unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
72 static const struct block_device_operations xlvbd_block_fops;
74 #define BLK_RING_SIZE __RING_SIZE((struct blkif_sring *)0, PAGE_SIZE)
77 * We have one of these per vbd, whether ide, scsi or 'other'. They
78 * hang in private_data off the gendisk structure. We may end up
79 * putting all kinds of interesting stuff here :-)
84 struct xenbus_device *xbdev;
88 enum blkif_state connected;
90 struct blkif_front_ring ring;
91 struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
92 unsigned int evtchn, irq;
93 struct request_queue *rq;
94 struct work_struct work;
95 struct gnttab_free_callback callback;
96 struct blk_shadow shadow[BLK_RING_SIZE];
97 unsigned long shadow_free;
98 unsigned int feature_flush;
102 static DEFINE_SPINLOCK(blkif_io_lock);
104 static unsigned int nr_minors;
105 static unsigned long *minors;
106 static DEFINE_SPINLOCK(minor_lock);
108 #define MAXIMUM_OUTSTANDING_BLOCK_REQS \
109 (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
110 #define GRANT_INVALID_REF 0
112 #define PARTS_PER_DISK 16
113 #define PARTS_PER_EXT_DISK 256
115 #define BLKIF_MAJOR(dev) ((dev)>>8)
116 #define BLKIF_MINOR(dev) ((dev) & 0xff)
119 #define EXTENDED (1<<EXT_SHIFT)
120 #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
121 #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
123 #define DEV_NAME "xvd" /* name in /dev */
125 static int get_id_from_freelist(struct blkfront_info *info)
127 unsigned long free = info->shadow_free;
128 BUG_ON(free >= BLK_RING_SIZE);
129 info->shadow_free = info->shadow[free].req.id;
130 info->shadow[free].req.id = 0x0fffffee; /* debug */
134 static void add_id_to_freelist(struct blkfront_info *info,
137 info->shadow[id].req.id = info->shadow_free;
138 info->shadow[id].request = 0;
139 info->shadow_free = id;
142 static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
144 unsigned int end = minor + nr;
147 if (end > nr_minors) {
148 unsigned long *bitmap, *old;
150 bitmap = kzalloc(BITS_TO_LONGS(end) * sizeof(*bitmap),
155 spin_lock(&minor_lock);
156 if (end > nr_minors) {
158 memcpy(bitmap, minors,
159 BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
161 nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
164 spin_unlock(&minor_lock);
168 spin_lock(&minor_lock);
169 if (find_next_bit(minors, end, minor) >= end) {
170 for (; minor < end; ++minor)
171 __set_bit(minor, minors);
175 spin_unlock(&minor_lock);
180 static void xlbd_release_minors(unsigned int minor, unsigned int nr)
182 unsigned int end = minor + nr;
184 BUG_ON(end > nr_minors);
185 spin_lock(&minor_lock);
186 for (; minor < end; ++minor)
187 __clear_bit(minor, minors);
188 spin_unlock(&minor_lock);
191 static void blkif_restart_queue_callback(void *arg)
193 struct blkfront_info *info = (struct blkfront_info *)arg;
194 schedule_work(&info->work);
197 static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
199 /* We don't have real geometry info, but let's at least return
200 values consistent with the size of the device */
201 sector_t nsect = get_capacity(bd->bd_disk);
202 sector_t cylinders = nsect;
206 sector_div(cylinders, hg->heads * hg->sectors);
207 hg->cylinders = cylinders;
208 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
209 hg->cylinders = 0xffff;
213 static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
214 unsigned command, unsigned long argument)
216 struct blkfront_info *info = bdev->bd_disk->private_data;
219 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
220 command, (long)argument);
223 case CDROMMULTISESSION:
224 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
225 for (i = 0; i < sizeof(struct cdrom_multisession); i++)
226 if (put_user(0, (char __user *)(argument + i)))
230 case CDROM_GET_CAPABILITY: {
231 struct gendisk *gd = info->gd;
232 if (gd->flags & GENHD_FL_CD)
238 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
240 return -EINVAL; /* same return as native Linux */
247 * blkif_queue_request
251 * id: for guest use only.
252 * operation: BLKIF_OP_{READ,WRITE,PROBE}
253 * buffer: buffer to read/write into. this should be a
254 * virtual address in the guest os.
256 static int blkif_queue_request(struct request *req)
258 struct blkfront_info *info = req->rq_disk->private_data;
259 unsigned long buffer_mfn;
260 struct blkif_request *ring_req;
262 unsigned int fsect, lsect;
264 grant_ref_t gref_head;
265 struct scatterlist *sg;
267 if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
270 if (gnttab_alloc_grant_references(
271 BLKIF_MAX_SEGMENTS_PER_REQUEST, &gref_head) < 0) {
272 gnttab_request_free_callback(
274 blkif_restart_queue_callback,
276 BLKIF_MAX_SEGMENTS_PER_REQUEST);
280 /* Fill out a communications ring structure. */
281 ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
282 id = get_id_from_freelist(info);
283 info->shadow[id].request = (unsigned long)req;
286 ring_req->sector_number = (blkif_sector_t)blk_rq_pos(req);
287 ring_req->handle = info->handle;
289 ring_req->operation = rq_data_dir(req) ?
290 BLKIF_OP_WRITE : BLKIF_OP_READ;
291 if (req->cmd_flags & REQ_HARDBARRIER)
292 ring_req->operation = BLKIF_OP_WRITE_BARRIER;
294 ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
295 BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
297 for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
298 buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
299 fsect = sg->offset >> 9;
300 lsect = fsect + (sg->length >> 9) - 1;
301 /* install a grant reference. */
302 ref = gnttab_claim_grant_reference(&gref_head);
303 BUG_ON(ref == -ENOSPC);
305 gnttab_grant_foreign_access_ref(
307 info->xbdev->otherend_id,
311 info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
313 (struct blkif_request_segment) {
316 .last_sect = lsect };
319 info->ring.req_prod_pvt++;
321 /* Keep a private copy so we can reissue requests when recovering. */
322 info->shadow[id].req = *ring_req;
324 gnttab_free_grant_references(gref_head);
330 static inline void flush_requests(struct blkfront_info *info)
334 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify);
337 notify_remote_via_irq(info->irq);
342 * read a block; request is in a request queue
344 static void do_blkif_request(struct request_queue *rq)
346 struct blkfront_info *info = NULL;
350 pr_debug("Entered do_blkif_request\n");
354 while ((req = blk_peek_request(rq)) != NULL) {
355 info = req->rq_disk->private_data;
357 if (RING_FULL(&info->ring))
360 blk_start_request(req);
362 if (req->cmd_type != REQ_TYPE_FS) {
363 __blk_end_request_all(req, -EIO);
367 pr_debug("do_blk_req %p: cmd %p, sec %lx, "
368 "(%u/%u) buffer:%p [%s]\n",
369 req, req->cmd, (unsigned long)blk_rq_pos(req),
370 blk_rq_cur_sectors(req), blk_rq_sectors(req),
371 req->buffer, rq_data_dir(req) ? "write" : "read");
373 if (blkif_queue_request(req)) {
374 blk_requeue_request(rq, req);
376 /* Avoid pointless unplugs. */
385 flush_requests(info);
388 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
390 struct request_queue *rq;
392 rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
396 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
398 /* Hard sector size and max sectors impersonate the equiv. hardware. */
399 blk_queue_logical_block_size(rq, sector_size);
400 blk_queue_max_hw_sectors(rq, 512);
402 /* Each segment in a request is up to an aligned page in size. */
403 blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
404 blk_queue_max_segment_size(rq, PAGE_SIZE);
406 /* Ensure a merged request will fit in a single I/O ring slot. */
407 blk_queue_max_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST);
409 /* Make sure buffer addresses are sector-aligned. */
410 blk_queue_dma_alignment(rq, 511);
412 /* Make sure we don't use bounce buffers. */
413 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
421 static void xlvbd_flush(struct blkfront_info *info)
423 blk_queue_flush(info->rq, info->feature_flush);
424 printk(KERN_INFO "blkfront: %s: barriers %s\n",
426 info->feature_flush ? "enabled" : "disabled");
430 static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
431 struct blkfront_info *info,
432 u16 vdisk_info, u16 sector_size)
441 BUG_ON(info->gd != NULL);
442 BUG_ON(info->rq != NULL);
444 if ((info->vdevice>>EXT_SHIFT) > 1) {
445 /* this is above the extended range; something is wrong */
446 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice);
450 if (!VDEV_IS_EXTENDED(info->vdevice)) {
451 minor = BLKIF_MINOR(info->vdevice);
452 nr_parts = PARTS_PER_DISK;
454 minor = BLKIF_MINOR_EXT(info->vdevice);
455 nr_parts = PARTS_PER_EXT_DISK;
458 if ((minor % nr_parts) == 0)
459 nr_minors = nr_parts;
461 err = xlbd_reserve_minors(minor, nr_minors);
466 gd = alloc_disk(nr_minors);
470 offset = minor / nr_parts;
474 sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset);
476 sprintf(gd->disk_name, "%s%c%c", DEV_NAME,
477 'a' + ((offset / 26)-1), 'a' + (offset % 26));
480 sprintf(gd->disk_name, "%s%c%d", DEV_NAME,
482 minor & (nr_parts - 1));
484 sprintf(gd->disk_name, "%s%c%c%d", DEV_NAME,
485 'a' + ((offset / 26) - 1),
487 minor & (nr_parts - 1));
490 gd->major = XENVBD_MAJOR;
491 gd->first_minor = minor;
492 gd->fops = &xlvbd_block_fops;
493 gd->private_data = info;
494 gd->driverfs_dev = &(info->xbdev->dev);
495 set_capacity(gd, capacity);
497 if (xlvbd_init_blk_queue(gd, sector_size)) {
502 info->rq = gd->queue;
507 if (vdisk_info & VDISK_READONLY)
510 if (vdisk_info & VDISK_REMOVABLE)
511 gd->flags |= GENHD_FL_REMOVABLE;
513 if (vdisk_info & VDISK_CDROM)
514 gd->flags |= GENHD_FL_CD;
519 xlbd_release_minors(minor, nr_minors);
524 static void xlvbd_release_gendisk(struct blkfront_info *info)
526 unsigned int minor, nr_minors;
529 if (info->rq == NULL)
532 spin_lock_irqsave(&blkif_io_lock, flags);
534 /* No more blkif_request(). */
535 blk_stop_queue(info->rq);
537 /* No more gnttab callback work. */
538 gnttab_cancel_free_callback(&info->callback);
539 spin_unlock_irqrestore(&blkif_io_lock, flags);
541 /* Flush gnttab callback work. Must be done with no locks held. */
542 flush_scheduled_work();
544 del_gendisk(info->gd);
546 minor = info->gd->first_minor;
547 nr_minors = info->gd->minors;
548 xlbd_release_minors(minor, nr_minors);
550 blk_cleanup_queue(info->rq);
557 static void kick_pending_request_queues(struct blkfront_info *info)
559 if (!RING_FULL(&info->ring)) {
560 /* Re-enable calldowns. */
561 blk_start_queue(info->rq);
562 /* Kick things off immediately. */
563 do_blkif_request(info->rq);
567 static void blkif_restart_queue(struct work_struct *work)
569 struct blkfront_info *info = container_of(work, struct blkfront_info, work);
571 spin_lock_irq(&blkif_io_lock);
572 if (info->connected == BLKIF_STATE_CONNECTED)
573 kick_pending_request_queues(info);
574 spin_unlock_irq(&blkif_io_lock);
577 static void blkif_free(struct blkfront_info *info, int suspend)
579 /* Prevent new requests being issued until we fix things up. */
580 spin_lock_irq(&blkif_io_lock);
581 info->connected = suspend ?
582 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
583 /* No more blkif_request(). */
585 blk_stop_queue(info->rq);
586 /* No more gnttab callback work. */
587 gnttab_cancel_free_callback(&info->callback);
588 spin_unlock_irq(&blkif_io_lock);
590 /* Flush gnttab callback work. Must be done with no locks held. */
591 flush_scheduled_work();
593 /* Free resources associated with old device channel. */
594 if (info->ring_ref != GRANT_INVALID_REF) {
595 gnttab_end_foreign_access(info->ring_ref, 0,
596 (unsigned long)info->ring.sring);
597 info->ring_ref = GRANT_INVALID_REF;
598 info->ring.sring = NULL;
601 unbind_from_irqhandler(info->irq, info);
602 info->evtchn = info->irq = 0;
606 static void blkif_completion(struct blk_shadow *s)
609 for (i = 0; i < s->req.nr_segments; i++)
610 gnttab_end_foreign_access(s->req.seg[i].gref, 0, 0UL);
613 static irqreturn_t blkif_interrupt(int irq, void *dev_id)
616 struct blkif_response *bret;
619 struct blkfront_info *info = (struct blkfront_info *)dev_id;
622 spin_lock_irqsave(&blkif_io_lock, flags);
624 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
625 spin_unlock_irqrestore(&blkif_io_lock, flags);
630 rp = info->ring.sring->rsp_prod;
631 rmb(); /* Ensure we see queued responses up to 'rp'. */
633 for (i = info->ring.rsp_cons; i != rp; i++) {
636 bret = RING_GET_RESPONSE(&info->ring, i);
638 req = (struct request *)info->shadow[id].request;
640 blkif_completion(&info->shadow[id]);
642 add_id_to_freelist(info, id);
644 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
645 switch (bret->operation) {
646 case BLKIF_OP_WRITE_BARRIER:
647 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
648 printk(KERN_WARNING "blkfront: %s: write barrier op failed\n",
649 info->gd->disk_name);
651 info->feature_flush = 0;
657 if (unlikely(bret->status != BLKIF_RSP_OKAY))
658 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
659 "request: %x\n", bret->status);
661 __blk_end_request_all(req, error);
668 info->ring.rsp_cons = i;
670 if (i != info->ring.req_prod_pvt) {
672 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
676 info->ring.sring->rsp_event = i + 1;
678 kick_pending_request_queues(info);
680 spin_unlock_irqrestore(&blkif_io_lock, flags);
686 static int setup_blkring(struct xenbus_device *dev,
687 struct blkfront_info *info)
689 struct blkif_sring *sring;
692 info->ring_ref = GRANT_INVALID_REF;
694 sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
696 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
699 SHARED_RING_INIT(sring);
700 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
702 sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
704 err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
706 free_page((unsigned long)sring);
707 info->ring.sring = NULL;
710 info->ring_ref = err;
712 err = xenbus_alloc_evtchn(dev, &info->evtchn);
716 err = bind_evtchn_to_irqhandler(info->evtchn,
718 IRQF_SAMPLE_RANDOM, "blkif", info);
720 xenbus_dev_fatal(dev, err,
721 "bind_evtchn_to_irqhandler failed");
733 /* Common code used when first setting up, and when resuming. */
734 static int talk_to_blkback(struct xenbus_device *dev,
735 struct blkfront_info *info)
737 const char *message = NULL;
738 struct xenbus_transaction xbt;
741 /* Create shared ring, alloc event channel. */
742 err = setup_blkring(dev, info);
747 err = xenbus_transaction_start(&xbt);
749 xenbus_dev_fatal(dev, err, "starting transaction");
750 goto destroy_blkring;
753 err = xenbus_printf(xbt, dev->nodename,
754 "ring-ref", "%u", info->ring_ref);
756 message = "writing ring-ref";
757 goto abort_transaction;
759 err = xenbus_printf(xbt, dev->nodename,
760 "event-channel", "%u", info->evtchn);
762 message = "writing event-channel";
763 goto abort_transaction;
765 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
766 XEN_IO_PROTO_ABI_NATIVE);
768 message = "writing protocol";
769 goto abort_transaction;
772 err = xenbus_transaction_end(xbt, 0);
776 xenbus_dev_fatal(dev, err, "completing transaction");
777 goto destroy_blkring;
780 xenbus_switch_state(dev, XenbusStateInitialised);
785 xenbus_transaction_end(xbt, 1);
787 xenbus_dev_fatal(dev, err, "%s", message);
795 * Entry point to this code when a new device is created. Allocate the basic
796 * structures and the ring buffer for communication with the backend, and
797 * inform the backend of the appropriate details for those. Switch to
800 static int blkfront_probe(struct xenbus_device *dev,
801 const struct xenbus_device_id *id)
804 struct blkfront_info *info;
806 /* FIXME: Use dynamic device id if this is not set. */
807 err = xenbus_scanf(XBT_NIL, dev->nodename,
808 "virtual-device", "%i", &vdevice);
810 /* go looking in the extended area instead */
811 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext",
814 xenbus_dev_fatal(dev, err, "reading virtual-device");
819 if (xen_hvm_domain()) {
822 /* no unplug has been done: do not hook devices != xen vbds */
823 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) {
826 if (!VDEV_IS_EXTENDED(vdevice))
827 major = BLKIF_MAJOR(vdevice);
829 major = XENVBD_MAJOR;
831 if (major != XENVBD_MAJOR) {
833 "%s: HVM does not support vbd %d as xen block device\n",
834 __FUNCTION__, vdevice);
838 /* do not create a PV cdrom device if we are an HVM guest */
839 type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
842 if (strncmp(type, "cdrom", 5) == 0) {
848 info = kzalloc(sizeof(*info), GFP_KERNEL);
850 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
854 mutex_init(&info->mutex);
856 info->vdevice = vdevice;
857 info->connected = BLKIF_STATE_DISCONNECTED;
858 INIT_WORK(&info->work, blkif_restart_queue);
860 for (i = 0; i < BLK_RING_SIZE; i++)
861 info->shadow[i].req.id = i+1;
862 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
864 /* Front end dir is a number, which is used as the id. */
865 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
866 dev_set_drvdata(&dev->dev, info);
868 err = talk_to_blkback(dev, info);
871 dev_set_drvdata(&dev->dev, NULL);
879 static int blkif_recover(struct blkfront_info *info)
882 struct blkif_request *req;
883 struct blk_shadow *copy;
886 /* Stage 1: Make a safe copy of the shadow state. */
887 copy = kmalloc(sizeof(info->shadow),
888 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
891 memcpy(copy, info->shadow, sizeof(info->shadow));
893 /* Stage 2: Set up free list. */
894 memset(&info->shadow, 0, sizeof(info->shadow));
895 for (i = 0; i < BLK_RING_SIZE; i++)
896 info->shadow[i].req.id = i+1;
897 info->shadow_free = info->ring.req_prod_pvt;
898 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
900 /* Stage 3: Find pending requests and requeue them. */
901 for (i = 0; i < BLK_RING_SIZE; i++) {
903 if (copy[i].request == 0)
906 /* Grab a request slot and copy shadow state into it. */
907 req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
910 /* We get a new request id, and must reset the shadow state. */
911 req->id = get_id_from_freelist(info);
912 memcpy(&info->shadow[req->id], ©[i], sizeof(copy[i]));
914 /* Rewrite any grant references invalidated by susp/resume. */
915 for (j = 0; j < req->nr_segments; j++)
916 gnttab_grant_foreign_access_ref(
918 info->xbdev->otherend_id,
919 pfn_to_mfn(info->shadow[req->id].frame[j]),
922 info->shadow[req->id].request));
923 info->shadow[req->id].req = *req;
925 info->ring.req_prod_pvt++;
930 xenbus_switch_state(info->xbdev, XenbusStateConnected);
932 spin_lock_irq(&blkif_io_lock);
934 /* Now safe for us to use the shared ring */
935 info->connected = BLKIF_STATE_CONNECTED;
937 /* Send off requeued requests */
938 flush_requests(info);
940 /* Kick any other new requests queued since we resumed */
941 kick_pending_request_queues(info);
943 spin_unlock_irq(&blkif_io_lock);
949 * We are reconnecting to the backend, due to a suspend/resume, or a backend
950 * driver restart. We tear down our blkif structure and recreate it, but
951 * leave the device-layer structures intact so that this is transparent to the
952 * rest of the kernel.
954 static int blkfront_resume(struct xenbus_device *dev)
956 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
959 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
961 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
963 err = talk_to_blkback(dev, info);
964 if (info->connected == BLKIF_STATE_SUSPENDED && !err)
965 err = blkif_recover(info);
971 blkfront_closing(struct blkfront_info *info)
973 struct xenbus_device *xbdev = info->xbdev;
974 struct block_device *bdev = NULL;
976 mutex_lock(&info->mutex);
978 if (xbdev->state == XenbusStateClosing) {
979 mutex_unlock(&info->mutex);
984 bdev = bdget_disk(info->gd, 0);
986 mutex_unlock(&info->mutex);
989 xenbus_frontend_closed(xbdev);
993 mutex_lock(&bdev->bd_mutex);
995 if (bdev->bd_openers) {
996 xenbus_dev_error(xbdev, -EBUSY,
997 "Device in use; refusing to close");
998 xenbus_switch_state(xbdev, XenbusStateClosing);
1000 xlvbd_release_gendisk(info);
1001 xenbus_frontend_closed(xbdev);
1004 mutex_unlock(&bdev->bd_mutex);
1009 * Invoked when the backend is finally 'ready' (and has told produced
1010 * the details about the physical device - #sectors, size, etc).
1012 static void blkfront_connect(struct blkfront_info *info)
1014 unsigned long long sectors;
1015 unsigned long sector_size;
1020 switch (info->connected) {
1021 case BLKIF_STATE_CONNECTED:
1023 * Potentially, the back-end may be signalling
1024 * a capacity change; update the capacity.
1026 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1027 "sectors", "%Lu", §ors);
1028 if (XENBUS_EXIST_ERR(err))
1030 printk(KERN_INFO "Setting capacity to %Lu\n",
1032 set_capacity(info->gd, sectors);
1033 revalidate_disk(info->gd);
1036 case BLKIF_STATE_SUSPENDED:
1043 dev_dbg(&info->xbdev->dev, "%s:%s.\n",
1044 __func__, info->xbdev->otherend);
1046 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1047 "sectors", "%llu", §ors,
1048 "info", "%u", &binfo,
1049 "sector-size", "%lu", §or_size,
1052 xenbus_dev_fatal(info->xbdev, err,
1053 "reading backend fields at %s",
1054 info->xbdev->otherend);
1058 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1059 "feature-barrier", "%lu", &barrier,
1063 * If there's no "feature-barrier" defined, then it means
1064 * we're dealing with a very old backend which writes
1065 * synchronously; nothing to do.
1067 * If there are barriers, then we use flush.
1069 info->feature_flush = 0;
1070 if (!err && barrier)
1071 info->feature_flush = REQ_FLUSH;
1073 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
1075 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
1076 info->xbdev->otherend);
1080 xenbus_switch_state(info->xbdev, XenbusStateConnected);
1082 /* Kick pending requests. */
1083 spin_lock_irq(&blkif_io_lock);
1084 info->connected = BLKIF_STATE_CONNECTED;
1085 kick_pending_request_queues(info);
1086 spin_unlock_irq(&blkif_io_lock);
1094 * Callback received when the backend's state changes.
1096 static void blkback_changed(struct xenbus_device *dev,
1097 enum xenbus_state backend_state)
1099 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1101 dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state);
1103 switch (backend_state) {
1104 case XenbusStateInitialising:
1105 case XenbusStateInitWait:
1106 case XenbusStateInitialised:
1107 case XenbusStateUnknown:
1108 case XenbusStateClosed:
1111 case XenbusStateConnected:
1112 blkfront_connect(info);
1115 case XenbusStateClosing:
1116 blkfront_closing(info);
1121 static int blkfront_remove(struct xenbus_device *xbdev)
1123 struct blkfront_info *info = dev_get_drvdata(&xbdev->dev);
1124 struct block_device *bdev = NULL;
1125 struct gendisk *disk;
1127 dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
1129 blkif_free(info, 0);
1131 mutex_lock(&info->mutex);
1135 bdev = bdget_disk(disk, 0);
1138 mutex_unlock(&info->mutex);
1146 * The xbdev was removed before we reached the Closed
1147 * state. See if it's safe to remove the disk. If the bdev
1148 * isn't closed yet, we let release take care of it.
1151 mutex_lock(&bdev->bd_mutex);
1152 info = disk->private_data;
1154 dev_warn(disk_to_dev(disk),
1155 "%s was hot-unplugged, %d stale handles\n",
1156 xbdev->nodename, bdev->bd_openers);
1158 if (info && !bdev->bd_openers) {
1159 xlvbd_release_gendisk(info);
1160 disk->private_data = NULL;
1164 mutex_unlock(&bdev->bd_mutex);
1170 static int blkfront_is_ready(struct xenbus_device *dev)
1172 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1174 return info->is_ready && info->xbdev;
1177 static int blkif_open(struct block_device *bdev, fmode_t mode)
1179 struct gendisk *disk = bdev->bd_disk;
1180 struct blkfront_info *info;
1185 info = disk->private_data;
1192 mutex_lock(&info->mutex);
1195 /* xbdev is closed */
1198 mutex_unlock(&info->mutex);
1205 static int blkif_release(struct gendisk *disk, fmode_t mode)
1207 struct blkfront_info *info = disk->private_data;
1208 struct block_device *bdev;
1209 struct xenbus_device *xbdev;
1213 bdev = bdget_disk(disk, 0);
1216 if (bdev->bd_openers)
1220 * Check if we have been instructed to close. We will have
1221 * deferred this request, because the bdev was still open.
1224 mutex_lock(&info->mutex);
1225 xbdev = info->xbdev;
1227 if (xbdev && xbdev->state == XenbusStateClosing) {
1228 /* pending switch to state closed */
1229 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
1230 xlvbd_release_gendisk(info);
1231 xenbus_frontend_closed(info->xbdev);
1234 mutex_unlock(&info->mutex);
1237 /* sudden device removal */
1238 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
1239 xlvbd_release_gendisk(info);
1240 disk->private_data = NULL;
1249 static const struct block_device_operations xlvbd_block_fops =
1251 .owner = THIS_MODULE,
1253 .release = blkif_release,
1254 .getgeo = blkif_getgeo,
1255 .ioctl = blkif_ioctl,
1259 static const struct xenbus_device_id blkfront_ids[] = {
1264 static struct xenbus_driver blkfront = {
1266 .owner = THIS_MODULE,
1267 .ids = blkfront_ids,
1268 .probe = blkfront_probe,
1269 .remove = blkfront_remove,
1270 .resume = blkfront_resume,
1271 .otherend_changed = blkback_changed,
1272 .is_ready = blkfront_is_ready,
1275 static int __init xlblk_init(void)
1280 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
1281 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
1282 XENVBD_MAJOR, DEV_NAME);
1286 return xenbus_register_frontend(&blkfront);
1288 module_init(xlblk_init);
1291 static void __exit xlblk_exit(void)
1293 return xenbus_unregister_driver(&blkfront);
1295 module_exit(xlblk_exit);
1297 MODULE_DESCRIPTION("Xen virtual block device frontend");
1298 MODULE_LICENSE("GPL");
1299 MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
1300 MODULE_ALIAS("xen:vbd");
1301 MODULE_ALIAS("xenblk");