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/mutex.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 struct request *request;
69 unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
72 static DEFINE_MUTEX(blkfront_mutex);
73 static const struct block_device_operations xlvbd_block_fops;
75 #define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
78 * We have one of these per vbd, whether ide, scsi or 'other'. They
79 * hang in private_data off the gendisk structure. We may end up
80 * putting all kinds of interesting stuff here :-)
85 struct xenbus_device *xbdev;
89 enum blkif_state connected;
91 struct blkif_front_ring ring;
92 struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
93 unsigned int evtchn, irq;
94 struct request_queue *rq;
95 struct work_struct work;
96 struct gnttab_free_callback callback;
97 struct blk_shadow shadow[BLK_RING_SIZE];
98 unsigned long shadow_free;
99 unsigned int feature_flush;
100 unsigned int flush_op;
101 unsigned int feature_discard;
102 unsigned int discard_granularity;
103 unsigned int discard_alignment;
107 static DEFINE_SPINLOCK(blkif_io_lock);
109 static unsigned int nr_minors;
110 static unsigned long *minors;
111 static DEFINE_SPINLOCK(minor_lock);
113 #define MAXIMUM_OUTSTANDING_BLOCK_REQS \
114 (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
115 #define GRANT_INVALID_REF 0
117 #define PARTS_PER_DISK 16
118 #define PARTS_PER_EXT_DISK 256
120 #define BLKIF_MAJOR(dev) ((dev)>>8)
121 #define BLKIF_MINOR(dev) ((dev) & 0xff)
124 #define EXTENDED (1<<EXT_SHIFT)
125 #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
126 #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
127 #define EMULATED_HD_DISK_MINOR_OFFSET (0)
128 #define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256)
129 #define EMULATED_SD_DISK_MINOR_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET + (4 * 16))
130 #define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_HD_DISK_NAME_OFFSET + 4)
132 #define DEV_NAME "xvd" /* name in /dev */
134 static int get_id_from_freelist(struct blkfront_info *info)
136 unsigned long free = info->shadow_free;
137 BUG_ON(free >= BLK_RING_SIZE);
138 info->shadow_free = info->shadow[free].req.id;
139 info->shadow[free].req.id = 0x0fffffee; /* debug */
143 static void add_id_to_freelist(struct blkfront_info *info,
146 info->shadow[id].req.id = info->shadow_free;
147 info->shadow[id].request = NULL;
148 info->shadow_free = id;
151 static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
153 unsigned int end = minor + nr;
156 if (end > nr_minors) {
157 unsigned long *bitmap, *old;
159 bitmap = kzalloc(BITS_TO_LONGS(end) * sizeof(*bitmap),
164 spin_lock(&minor_lock);
165 if (end > nr_minors) {
167 memcpy(bitmap, minors,
168 BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
170 nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
173 spin_unlock(&minor_lock);
177 spin_lock(&minor_lock);
178 if (find_next_bit(minors, end, minor) >= end) {
179 for (; minor < end; ++minor)
180 __set_bit(minor, minors);
184 spin_unlock(&minor_lock);
189 static void xlbd_release_minors(unsigned int minor, unsigned int nr)
191 unsigned int end = minor + nr;
193 BUG_ON(end > nr_minors);
194 spin_lock(&minor_lock);
195 for (; minor < end; ++minor)
196 __clear_bit(minor, minors);
197 spin_unlock(&minor_lock);
200 static void blkif_restart_queue_callback(void *arg)
202 struct blkfront_info *info = (struct blkfront_info *)arg;
203 schedule_work(&info->work);
206 static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
208 /* We don't have real geometry info, but let's at least return
209 values consistent with the size of the device */
210 sector_t nsect = get_capacity(bd->bd_disk);
211 sector_t cylinders = nsect;
215 sector_div(cylinders, hg->heads * hg->sectors);
216 hg->cylinders = cylinders;
217 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
218 hg->cylinders = 0xffff;
222 static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
223 unsigned command, unsigned long argument)
225 struct blkfront_info *info = bdev->bd_disk->private_data;
228 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
229 command, (long)argument);
232 case CDROMMULTISESSION:
233 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
234 for (i = 0; i < sizeof(struct cdrom_multisession); i++)
235 if (put_user(0, (char __user *)(argument + i)))
239 case CDROM_GET_CAPABILITY: {
240 struct gendisk *gd = info->gd;
241 if (gd->flags & GENHD_FL_CD)
247 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
249 return -EINVAL; /* same return as native Linux */
256 * Generate a Xen blkfront IO request from a blk layer request. Reads
257 * and writes are handled as expected.
259 * @req: a request struct
261 static int blkif_queue_request(struct request *req)
263 struct blkfront_info *info = req->rq_disk->private_data;
264 unsigned long buffer_mfn;
265 struct blkif_request *ring_req;
267 unsigned int fsect, lsect;
269 grant_ref_t gref_head;
270 struct scatterlist *sg;
272 if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
275 if (gnttab_alloc_grant_references(
276 BLKIF_MAX_SEGMENTS_PER_REQUEST, &gref_head) < 0) {
277 gnttab_request_free_callback(
279 blkif_restart_queue_callback,
281 BLKIF_MAX_SEGMENTS_PER_REQUEST);
285 /* Fill out a communications ring structure. */
286 ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
287 id = get_id_from_freelist(info);
288 info->shadow[id].request = req;
291 ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req);
292 ring_req->handle = info->handle;
294 ring_req->operation = rq_data_dir(req) ?
295 BLKIF_OP_WRITE : BLKIF_OP_READ;
297 if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
299 * Ideally we can do an unordered flush-to-disk. In case the
300 * backend onlysupports barriers, use that. A barrier request
301 * a superset of FUA, so we can implement it the same
302 * way. (It's also a FLUSH+FUA, since it is
303 * guaranteed ordered WRT previous writes.)
305 ring_req->operation = info->flush_op;
308 if (unlikely(req->cmd_flags & REQ_DISCARD)) {
309 /* id, sector_number and handle are set above. */
310 ring_req->operation = BLKIF_OP_DISCARD;
311 ring_req->nr_segments = 0;
312 ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
314 ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
315 BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
317 for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
318 buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
319 fsect = sg->offset >> 9;
320 lsect = fsect + (sg->length >> 9) - 1;
321 /* install a grant reference. */
322 ref = gnttab_claim_grant_reference(&gref_head);
323 BUG_ON(ref == -ENOSPC);
325 gnttab_grant_foreign_access_ref(
327 info->xbdev->otherend_id,
331 info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
332 ring_req->u.rw.seg[i] =
333 (struct blkif_request_segment) {
336 .last_sect = lsect };
340 info->ring.req_prod_pvt++;
342 /* Keep a private copy so we can reissue requests when recovering. */
343 info->shadow[id].req = *ring_req;
345 gnttab_free_grant_references(gref_head);
351 static inline void flush_requests(struct blkfront_info *info)
355 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify);
358 notify_remote_via_irq(info->irq);
363 * read a block; request is in a request queue
365 static void do_blkif_request(struct request_queue *rq)
367 struct blkfront_info *info = NULL;
371 pr_debug("Entered do_blkif_request\n");
375 while ((req = blk_peek_request(rq)) != NULL) {
376 info = req->rq_disk->private_data;
378 if (RING_FULL(&info->ring))
381 blk_start_request(req);
383 if (req->cmd_type != REQ_TYPE_FS) {
384 __blk_end_request_all(req, -EIO);
388 pr_debug("do_blk_req %p: cmd %p, sec %lx, "
389 "(%u/%u) buffer:%p [%s]\n",
390 req, req->cmd, (unsigned long)blk_rq_pos(req),
391 blk_rq_cur_sectors(req), blk_rq_sectors(req),
392 req->buffer, rq_data_dir(req) ? "write" : "read");
394 if (blkif_queue_request(req)) {
395 blk_requeue_request(rq, req);
397 /* Avoid pointless unplugs. */
406 flush_requests(info);
409 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
411 struct request_queue *rq;
412 struct blkfront_info *info = gd->private_data;
414 rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
418 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
420 if (info->feature_discard) {
421 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
422 blk_queue_max_discard_sectors(rq, get_capacity(gd));
423 rq->limits.discard_granularity = info->discard_granularity;
424 rq->limits.discard_alignment = info->discard_alignment;
427 /* Hard sector size and max sectors impersonate the equiv. hardware. */
428 blk_queue_logical_block_size(rq, sector_size);
429 blk_queue_max_hw_sectors(rq, 512);
431 /* Each segment in a request is up to an aligned page in size. */
432 blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
433 blk_queue_max_segment_size(rq, PAGE_SIZE);
435 /* Ensure a merged request will fit in a single I/O ring slot. */
436 blk_queue_max_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST);
438 /* Make sure buffer addresses are sector-aligned. */
439 blk_queue_dma_alignment(rq, 511);
441 /* Make sure we don't use bounce buffers. */
442 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
450 static void xlvbd_flush(struct blkfront_info *info)
452 blk_queue_flush(info->rq, info->feature_flush);
453 printk(KERN_INFO "blkfront: %s: %s: %s\n",
455 info->flush_op == BLKIF_OP_WRITE_BARRIER ?
456 "barrier" : (info->flush_op == BLKIF_OP_FLUSH_DISKCACHE ?
457 "flush diskcache" : "barrier or flush"),
458 info->feature_flush ? "enabled" : "disabled");
461 static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
464 major = BLKIF_MAJOR(vdevice);
465 *minor = BLKIF_MINOR(vdevice);
468 *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET;
469 *minor = ((*minor / 64) * PARTS_PER_DISK) +
470 EMULATED_HD_DISK_MINOR_OFFSET;
473 *offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET;
474 *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) +
475 EMULATED_HD_DISK_MINOR_OFFSET;
477 case XEN_SCSI_DISK0_MAJOR:
478 *offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET;
479 *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET;
481 case XEN_SCSI_DISK1_MAJOR:
482 case XEN_SCSI_DISK2_MAJOR:
483 case XEN_SCSI_DISK3_MAJOR:
484 case XEN_SCSI_DISK4_MAJOR:
485 case XEN_SCSI_DISK5_MAJOR:
486 case XEN_SCSI_DISK6_MAJOR:
487 case XEN_SCSI_DISK7_MAJOR:
488 *offset = (*minor / PARTS_PER_DISK) +
489 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) +
490 EMULATED_SD_DISK_NAME_OFFSET;
492 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) +
493 EMULATED_SD_DISK_MINOR_OFFSET;
495 case XEN_SCSI_DISK8_MAJOR:
496 case XEN_SCSI_DISK9_MAJOR:
497 case XEN_SCSI_DISK10_MAJOR:
498 case XEN_SCSI_DISK11_MAJOR:
499 case XEN_SCSI_DISK12_MAJOR:
500 case XEN_SCSI_DISK13_MAJOR:
501 case XEN_SCSI_DISK14_MAJOR:
502 case XEN_SCSI_DISK15_MAJOR:
503 *offset = (*minor / PARTS_PER_DISK) +
504 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) +
505 EMULATED_SD_DISK_NAME_OFFSET;
507 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) +
508 EMULATED_SD_DISK_MINOR_OFFSET;
511 *offset = *minor / PARTS_PER_DISK;
514 printk(KERN_WARNING "blkfront: your disk configuration is "
515 "incorrect, please use an xvd device instead\n");
521 static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
522 struct blkfront_info *info,
523 u16 vdisk_info, u16 sector_size)
532 BUG_ON(info->gd != NULL);
533 BUG_ON(info->rq != NULL);
535 if ((info->vdevice>>EXT_SHIFT) > 1) {
536 /* this is above the extended range; something is wrong */
537 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice);
541 if (!VDEV_IS_EXTENDED(info->vdevice)) {
542 err = xen_translate_vdev(info->vdevice, &minor, &offset);
545 nr_parts = PARTS_PER_DISK;
547 minor = BLKIF_MINOR_EXT(info->vdevice);
548 nr_parts = PARTS_PER_EXT_DISK;
549 offset = minor / nr_parts;
550 if (xen_hvm_domain() && offset <= EMULATED_HD_DISK_NAME_OFFSET + 4)
551 printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with "
552 "emulated IDE disks,\n\t choose an xvd device name"
553 "from xvde on\n", info->vdevice);
557 if ((minor % nr_parts) == 0)
558 nr_minors = nr_parts;
560 err = xlbd_reserve_minors(minor, nr_minors);
565 gd = alloc_disk(nr_minors);
571 sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset);
573 sprintf(gd->disk_name, "%s%c%c", DEV_NAME,
574 'a' + ((offset / 26)-1), 'a' + (offset % 26));
577 sprintf(gd->disk_name, "%s%c%d", DEV_NAME,
579 minor & (nr_parts - 1));
581 sprintf(gd->disk_name, "%s%c%c%d", DEV_NAME,
582 'a' + ((offset / 26) - 1),
584 minor & (nr_parts - 1));
587 gd->major = XENVBD_MAJOR;
588 gd->first_minor = minor;
589 gd->fops = &xlvbd_block_fops;
590 gd->private_data = info;
591 gd->driverfs_dev = &(info->xbdev->dev);
592 set_capacity(gd, capacity);
594 if (xlvbd_init_blk_queue(gd, sector_size)) {
599 info->rq = gd->queue;
604 if (vdisk_info & VDISK_READONLY)
607 if (vdisk_info & VDISK_REMOVABLE)
608 gd->flags |= GENHD_FL_REMOVABLE;
610 if (vdisk_info & VDISK_CDROM)
611 gd->flags |= GENHD_FL_CD;
616 xlbd_release_minors(minor, nr_minors);
621 static void xlvbd_release_gendisk(struct blkfront_info *info)
623 unsigned int minor, nr_minors;
626 if (info->rq == NULL)
629 spin_lock_irqsave(&blkif_io_lock, flags);
631 /* No more blkif_request(). */
632 blk_stop_queue(info->rq);
634 /* No more gnttab callback work. */
635 gnttab_cancel_free_callback(&info->callback);
636 spin_unlock_irqrestore(&blkif_io_lock, flags);
638 /* Flush gnttab callback work. Must be done with no locks held. */
639 flush_work_sync(&info->work);
641 del_gendisk(info->gd);
643 minor = info->gd->first_minor;
644 nr_minors = info->gd->minors;
645 xlbd_release_minors(minor, nr_minors);
647 blk_cleanup_queue(info->rq);
654 static void kick_pending_request_queues(struct blkfront_info *info)
656 if (!RING_FULL(&info->ring)) {
657 /* Re-enable calldowns. */
658 blk_start_queue(info->rq);
659 /* Kick things off immediately. */
660 do_blkif_request(info->rq);
664 static void blkif_restart_queue(struct work_struct *work)
666 struct blkfront_info *info = container_of(work, struct blkfront_info, work);
668 spin_lock_irq(&blkif_io_lock);
669 if (info->connected == BLKIF_STATE_CONNECTED)
670 kick_pending_request_queues(info);
671 spin_unlock_irq(&blkif_io_lock);
674 static void blkif_free(struct blkfront_info *info, int suspend)
676 /* Prevent new requests being issued until we fix things up. */
677 spin_lock_irq(&blkif_io_lock);
678 info->connected = suspend ?
679 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
680 /* No more blkif_request(). */
682 blk_stop_queue(info->rq);
683 /* No more gnttab callback work. */
684 gnttab_cancel_free_callback(&info->callback);
685 spin_unlock_irq(&blkif_io_lock);
687 /* Flush gnttab callback work. Must be done with no locks held. */
688 flush_work_sync(&info->work);
690 /* Free resources associated with old device channel. */
691 if (info->ring_ref != GRANT_INVALID_REF) {
692 gnttab_end_foreign_access(info->ring_ref, 0,
693 (unsigned long)info->ring.sring);
694 info->ring_ref = GRANT_INVALID_REF;
695 info->ring.sring = NULL;
698 unbind_from_irqhandler(info->irq, info);
699 info->evtchn = info->irq = 0;
703 static void blkif_completion(struct blk_shadow *s)
706 for (i = 0; i < s->req.nr_segments; i++)
707 gnttab_end_foreign_access(s->req.u.rw.seg[i].gref, 0, 0UL);
710 static irqreturn_t blkif_interrupt(int irq, void *dev_id)
713 struct blkif_response *bret;
716 struct blkfront_info *info = (struct blkfront_info *)dev_id;
719 spin_lock_irqsave(&blkif_io_lock, flags);
721 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
722 spin_unlock_irqrestore(&blkif_io_lock, flags);
727 rp = info->ring.sring->rsp_prod;
728 rmb(); /* Ensure we see queued responses up to 'rp'. */
730 for (i = info->ring.rsp_cons; i != rp; i++) {
733 bret = RING_GET_RESPONSE(&info->ring, i);
735 req = info->shadow[id].request;
737 blkif_completion(&info->shadow[id]);
739 add_id_to_freelist(info, id);
741 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
742 switch (bret->operation) {
743 case BLKIF_OP_DISCARD:
744 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
745 struct request_queue *rq = info->rq;
746 printk(KERN_WARNING "blkfront: %s: discard op failed\n",
747 info->gd->disk_name);
749 info->feature_discard = 0;
750 spin_lock(rq->queue_lock);
751 queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
752 spin_unlock(rq->queue_lock);
754 __blk_end_request_all(req, error);
756 case BLKIF_OP_FLUSH_DISKCACHE:
757 case BLKIF_OP_WRITE_BARRIER:
758 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
759 printk(KERN_WARNING "blkfront: %s: write %s op failed\n",
760 info->flush_op == BLKIF_OP_WRITE_BARRIER ?
761 "barrier" : "flush disk cache",
762 info->gd->disk_name);
765 if (unlikely(bret->status == BLKIF_RSP_ERROR &&
766 info->shadow[id].req.nr_segments == 0)) {
767 printk(KERN_WARNING "blkfront: %s: empty write %s op failed\n",
768 info->flush_op == BLKIF_OP_WRITE_BARRIER ?
769 "barrier" : "flush disk cache",
770 info->gd->disk_name);
773 if (unlikely(error)) {
774 if (error == -EOPNOTSUPP)
776 info->feature_flush = 0;
783 if (unlikely(bret->status != BLKIF_RSP_OKAY))
784 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
785 "request: %x\n", bret->status);
787 __blk_end_request_all(req, error);
794 info->ring.rsp_cons = i;
796 if (i != info->ring.req_prod_pvt) {
798 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
802 info->ring.sring->rsp_event = i + 1;
804 kick_pending_request_queues(info);
806 spin_unlock_irqrestore(&blkif_io_lock, flags);
812 static int setup_blkring(struct xenbus_device *dev,
813 struct blkfront_info *info)
815 struct blkif_sring *sring;
818 info->ring_ref = GRANT_INVALID_REF;
820 sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
822 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
825 SHARED_RING_INIT(sring);
826 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
828 sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
830 err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
832 free_page((unsigned long)sring);
833 info->ring.sring = NULL;
836 info->ring_ref = err;
838 err = xenbus_alloc_evtchn(dev, &info->evtchn);
842 err = bind_evtchn_to_irqhandler(info->evtchn,
844 IRQF_SAMPLE_RANDOM, "blkif", info);
846 xenbus_dev_fatal(dev, err,
847 "bind_evtchn_to_irqhandler failed");
859 /* Common code used when first setting up, and when resuming. */
860 static int talk_to_blkback(struct xenbus_device *dev,
861 struct blkfront_info *info)
863 const char *message = NULL;
864 struct xenbus_transaction xbt;
867 /* Create shared ring, alloc event channel. */
868 err = setup_blkring(dev, info);
873 err = xenbus_transaction_start(&xbt);
875 xenbus_dev_fatal(dev, err, "starting transaction");
876 goto destroy_blkring;
879 err = xenbus_printf(xbt, dev->nodename,
880 "ring-ref", "%u", info->ring_ref);
882 message = "writing ring-ref";
883 goto abort_transaction;
885 err = xenbus_printf(xbt, dev->nodename,
886 "event-channel", "%u", info->evtchn);
888 message = "writing event-channel";
889 goto abort_transaction;
891 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
892 XEN_IO_PROTO_ABI_NATIVE);
894 message = "writing protocol";
895 goto abort_transaction;
898 err = xenbus_transaction_end(xbt, 0);
902 xenbus_dev_fatal(dev, err, "completing transaction");
903 goto destroy_blkring;
906 xenbus_switch_state(dev, XenbusStateInitialised);
911 xenbus_transaction_end(xbt, 1);
913 xenbus_dev_fatal(dev, err, "%s", message);
921 * Entry point to this code when a new device is created. Allocate the basic
922 * structures and the ring buffer for communication with the backend, and
923 * inform the backend of the appropriate details for those. Switch to
926 static int blkfront_probe(struct xenbus_device *dev,
927 const struct xenbus_device_id *id)
930 struct blkfront_info *info;
932 /* FIXME: Use dynamic device id if this is not set. */
933 err = xenbus_scanf(XBT_NIL, dev->nodename,
934 "virtual-device", "%i", &vdevice);
936 /* go looking in the extended area instead */
937 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext",
940 xenbus_dev_fatal(dev, err, "reading virtual-device");
945 if (xen_hvm_domain()) {
948 /* no unplug has been done: do not hook devices != xen vbds */
949 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) {
952 if (!VDEV_IS_EXTENDED(vdevice))
953 major = BLKIF_MAJOR(vdevice);
955 major = XENVBD_MAJOR;
957 if (major != XENVBD_MAJOR) {
959 "%s: HVM does not support vbd %d as xen block device\n",
960 __FUNCTION__, vdevice);
964 /* do not create a PV cdrom device if we are an HVM guest */
965 type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
968 if (strncmp(type, "cdrom", 5) == 0) {
974 info = kzalloc(sizeof(*info), GFP_KERNEL);
976 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
980 mutex_init(&info->mutex);
982 info->vdevice = vdevice;
983 info->connected = BLKIF_STATE_DISCONNECTED;
984 INIT_WORK(&info->work, blkif_restart_queue);
986 for (i = 0; i < BLK_RING_SIZE; i++)
987 info->shadow[i].req.id = i+1;
988 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
990 /* Front end dir is a number, which is used as the id. */
991 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
992 dev_set_drvdata(&dev->dev, info);
994 err = talk_to_blkback(dev, info);
997 dev_set_drvdata(&dev->dev, NULL);
1005 static int blkif_recover(struct blkfront_info *info)
1008 struct blkif_request *req;
1009 struct blk_shadow *copy;
1012 /* Stage 1: Make a safe copy of the shadow state. */
1013 copy = kmalloc(sizeof(info->shadow),
1014 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
1017 memcpy(copy, info->shadow, sizeof(info->shadow));
1019 /* Stage 2: Set up free list. */
1020 memset(&info->shadow, 0, sizeof(info->shadow));
1021 for (i = 0; i < BLK_RING_SIZE; i++)
1022 info->shadow[i].req.id = i+1;
1023 info->shadow_free = info->ring.req_prod_pvt;
1024 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
1026 /* Stage 3: Find pending requests and requeue them. */
1027 for (i = 0; i < BLK_RING_SIZE; i++) {
1029 if (!copy[i].request)
1032 /* Grab a request slot and copy shadow state into it. */
1033 req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
1036 /* We get a new request id, and must reset the shadow state. */
1037 req->id = get_id_from_freelist(info);
1038 memcpy(&info->shadow[req->id], ©[i], sizeof(copy[i]));
1040 /* Rewrite any grant references invalidated by susp/resume. */
1041 for (j = 0; j < req->nr_segments; j++)
1042 gnttab_grant_foreign_access_ref(
1043 req->u.rw.seg[j].gref,
1044 info->xbdev->otherend_id,
1045 pfn_to_mfn(info->shadow[req->id].frame[j]),
1046 rq_data_dir(info->shadow[req->id].request));
1047 info->shadow[req->id].req = *req;
1049 info->ring.req_prod_pvt++;
1054 xenbus_switch_state(info->xbdev, XenbusStateConnected);
1056 spin_lock_irq(&blkif_io_lock);
1058 /* Now safe for us to use the shared ring */
1059 info->connected = BLKIF_STATE_CONNECTED;
1061 /* Send off requeued requests */
1062 flush_requests(info);
1064 /* Kick any other new requests queued since we resumed */
1065 kick_pending_request_queues(info);
1067 spin_unlock_irq(&blkif_io_lock);
1073 * We are reconnecting to the backend, due to a suspend/resume, or a backend
1074 * driver restart. We tear down our blkif structure and recreate it, but
1075 * leave the device-layer structures intact so that this is transparent to the
1076 * rest of the kernel.
1078 static int blkfront_resume(struct xenbus_device *dev)
1080 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1083 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
1085 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
1087 err = talk_to_blkback(dev, info);
1088 if (info->connected == BLKIF_STATE_SUSPENDED && !err)
1089 err = blkif_recover(info);
1095 blkfront_closing(struct blkfront_info *info)
1097 struct xenbus_device *xbdev = info->xbdev;
1098 struct block_device *bdev = NULL;
1100 mutex_lock(&info->mutex);
1102 if (xbdev->state == XenbusStateClosing) {
1103 mutex_unlock(&info->mutex);
1108 bdev = bdget_disk(info->gd, 0);
1110 mutex_unlock(&info->mutex);
1113 xenbus_frontend_closed(xbdev);
1117 mutex_lock(&bdev->bd_mutex);
1119 if (bdev->bd_openers) {
1120 xenbus_dev_error(xbdev, -EBUSY,
1121 "Device in use; refusing to close");
1122 xenbus_switch_state(xbdev, XenbusStateClosing);
1124 xlvbd_release_gendisk(info);
1125 xenbus_frontend_closed(xbdev);
1128 mutex_unlock(&bdev->bd_mutex);
1132 static void blkfront_setup_discard(struct blkfront_info *info)
1136 unsigned int discard_granularity;
1137 unsigned int discard_alignment;
1139 type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL);
1143 if (strncmp(type, "phy", 3) == 0) {
1144 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1145 "discard-granularity", "%u", &discard_granularity,
1146 "discard-alignment", "%u", &discard_alignment,
1149 info->feature_discard = 1;
1150 info->discard_granularity = discard_granularity;
1151 info->discard_alignment = discard_alignment;
1153 } else if (strncmp(type, "file", 4) == 0)
1154 info->feature_discard = 1;
1160 * Invoked when the backend is finally 'ready' (and has told produced
1161 * the details about the physical device - #sectors, size, etc).
1163 static void blkfront_connect(struct blkfront_info *info)
1165 unsigned long long sectors;
1166 unsigned long sector_size;
1169 int barrier, flush, discard;
1171 switch (info->connected) {
1172 case BLKIF_STATE_CONNECTED:
1174 * Potentially, the back-end may be signalling
1175 * a capacity change; update the capacity.
1177 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1178 "sectors", "%Lu", §ors);
1179 if (XENBUS_EXIST_ERR(err))
1181 printk(KERN_INFO "Setting capacity to %Lu\n",
1183 set_capacity(info->gd, sectors);
1184 revalidate_disk(info->gd);
1187 case BLKIF_STATE_SUSPENDED:
1194 dev_dbg(&info->xbdev->dev, "%s:%s.\n",
1195 __func__, info->xbdev->otherend);
1197 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1198 "sectors", "%llu", §ors,
1199 "info", "%u", &binfo,
1200 "sector-size", "%lu", §or_size,
1203 xenbus_dev_fatal(info->xbdev, err,
1204 "reading backend fields at %s",
1205 info->xbdev->otherend);
1209 info->feature_flush = 0;
1212 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1213 "feature-barrier", "%d", &barrier,
1217 * If there's no "feature-barrier" defined, then it means
1218 * we're dealing with a very old backend which writes
1219 * synchronously; nothing to do.
1221 * If there are barriers, then we use flush.
1223 if (!err && barrier) {
1224 info->feature_flush = REQ_FLUSH | REQ_FUA;
1225 info->flush_op = BLKIF_OP_WRITE_BARRIER;
1228 * And if there is "feature-flush-cache" use that above
1231 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1232 "feature-flush-cache", "%d", &flush,
1235 if (!err && flush) {
1236 info->feature_flush = REQ_FLUSH;
1237 info->flush_op = BLKIF_OP_FLUSH_DISKCACHE;
1240 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1241 "feature-discard", "%d", &discard,
1244 if (!err && discard)
1245 blkfront_setup_discard(info);
1247 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
1249 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
1250 info->xbdev->otherend);
1254 xenbus_switch_state(info->xbdev, XenbusStateConnected);
1256 /* Kick pending requests. */
1257 spin_lock_irq(&blkif_io_lock);
1258 info->connected = BLKIF_STATE_CONNECTED;
1259 kick_pending_request_queues(info);
1260 spin_unlock_irq(&blkif_io_lock);
1268 * Callback received when the backend's state changes.
1270 static void blkback_changed(struct xenbus_device *dev,
1271 enum xenbus_state backend_state)
1273 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1275 dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state);
1277 switch (backend_state) {
1278 case XenbusStateInitialising:
1279 case XenbusStateInitWait:
1280 case XenbusStateInitialised:
1281 case XenbusStateReconfiguring:
1282 case XenbusStateReconfigured:
1283 case XenbusStateUnknown:
1284 case XenbusStateClosed:
1287 case XenbusStateConnected:
1288 blkfront_connect(info);
1291 case XenbusStateClosing:
1292 blkfront_closing(info);
1297 static int blkfront_remove(struct xenbus_device *xbdev)
1299 struct blkfront_info *info = dev_get_drvdata(&xbdev->dev);
1300 struct block_device *bdev = NULL;
1301 struct gendisk *disk;
1303 dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
1305 blkif_free(info, 0);
1307 mutex_lock(&info->mutex);
1311 bdev = bdget_disk(disk, 0);
1314 mutex_unlock(&info->mutex);
1322 * The xbdev was removed before we reached the Closed
1323 * state. See if it's safe to remove the disk. If the bdev
1324 * isn't closed yet, we let release take care of it.
1327 mutex_lock(&bdev->bd_mutex);
1328 info = disk->private_data;
1330 dev_warn(disk_to_dev(disk),
1331 "%s was hot-unplugged, %d stale handles\n",
1332 xbdev->nodename, bdev->bd_openers);
1334 if (info && !bdev->bd_openers) {
1335 xlvbd_release_gendisk(info);
1336 disk->private_data = NULL;
1340 mutex_unlock(&bdev->bd_mutex);
1346 static int blkfront_is_ready(struct xenbus_device *dev)
1348 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1350 return info->is_ready && info->xbdev;
1353 static int blkif_open(struct block_device *bdev, fmode_t mode)
1355 struct gendisk *disk = bdev->bd_disk;
1356 struct blkfront_info *info;
1359 mutex_lock(&blkfront_mutex);
1361 info = disk->private_data;
1368 mutex_lock(&info->mutex);
1371 /* xbdev is closed */
1374 mutex_unlock(&info->mutex);
1377 mutex_unlock(&blkfront_mutex);
1381 static int blkif_release(struct gendisk *disk, fmode_t mode)
1383 struct blkfront_info *info = disk->private_data;
1384 struct block_device *bdev;
1385 struct xenbus_device *xbdev;
1387 mutex_lock(&blkfront_mutex);
1389 bdev = bdget_disk(disk, 0);
1392 if (bdev->bd_openers)
1396 * Check if we have been instructed to close. We will have
1397 * deferred this request, because the bdev was still open.
1400 mutex_lock(&info->mutex);
1401 xbdev = info->xbdev;
1403 if (xbdev && xbdev->state == XenbusStateClosing) {
1404 /* pending switch to state closed */
1405 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
1406 xlvbd_release_gendisk(info);
1407 xenbus_frontend_closed(info->xbdev);
1410 mutex_unlock(&info->mutex);
1413 /* sudden device removal */
1414 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
1415 xlvbd_release_gendisk(info);
1416 disk->private_data = NULL;
1421 mutex_unlock(&blkfront_mutex);
1425 static const struct block_device_operations xlvbd_block_fops =
1427 .owner = THIS_MODULE,
1429 .release = blkif_release,
1430 .getgeo = blkif_getgeo,
1431 .ioctl = blkif_ioctl,
1435 static const struct xenbus_device_id blkfront_ids[] = {
1440 static struct xenbus_driver blkfront = {
1442 .owner = THIS_MODULE,
1443 .ids = blkfront_ids,
1444 .probe = blkfront_probe,
1445 .remove = blkfront_remove,
1446 .resume = blkfront_resume,
1447 .otherend_changed = blkback_changed,
1448 .is_ready = blkfront_is_ready,
1451 static int __init xlblk_init(void)
1456 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
1457 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
1458 XENVBD_MAJOR, DEV_NAME);
1462 return xenbus_register_frontend(&blkfront);
1464 module_init(xlblk_init);
1467 static void __exit xlblk_exit(void)
1469 return xenbus_unregister_driver(&blkfront);
1471 module_exit(xlblk_exit);
1473 MODULE_DESCRIPTION("Xen virtual block device frontend");
1474 MODULE_LICENSE("GPL");
1475 MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
1476 MODULE_ALIAS("xen:vbd");
1477 MODULE_ALIAS("xenblk");