blob: b220c686089d82b5ffc41eada6efd59c7f7ca7e5 [file] [log] [blame]
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001/*
2 * blkfront.c
3 *
4 * XenLinux virtual block device driver.
5 *
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
12 *
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:
18 *
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:
25 *
26 * The above copyright notice and this permission notice shall be included in
27 * all copies or substantial portions of the Software.
28 *
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
35 * IN THE SOFTWARE.
36 */
37
38#include <linux/interrupt.h>
39#include <linux/blkdev.h>
Ian Campbell597592d2008-02-21 13:03:45 -080040#include <linux/hdreg.h>
Christian Limpach440a01a2008-06-17 10:47:08 +020041#include <linux/cdrom.h>
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070042#include <linux/module.h>
43
44#include <xen/xenbus.h>
45#include <xen/grant_table.h>
46#include <xen/events.h>
47#include <xen/page.h>
48
49#include <xen/interface/grant_table.h>
50#include <xen/interface/io/blkif.h>
Markus Armbruster3e334232008-04-02 10:54:02 -070051#include <xen/interface/io/protocols.h>
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070052
53#include <asm/xen/hypervisor.h>
54
55enum blkif_state {
56 BLKIF_STATE_DISCONNECTED,
57 BLKIF_STATE_CONNECTED,
58 BLKIF_STATE_SUSPENDED,
59};
60
61struct blk_shadow {
62 struct blkif_request req;
63 unsigned long request;
64 unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
65};
66
67static struct block_device_operations xlvbd_block_fops;
68
69#define BLK_RING_SIZE __RING_SIZE((struct blkif_sring *)0, PAGE_SIZE)
70
71/*
72 * We have one of these per vbd, whether ide, scsi or 'other'. They
73 * hang in private_data off the gendisk structure. We may end up
74 * putting all kinds of interesting stuff here :-)
75 */
76struct blkfront_info
77{
78 struct xenbus_device *xbdev;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070079 struct gendisk *gd;
80 int vdevice;
81 blkif_vdev_t handle;
82 enum blkif_state connected;
83 int ring_ref;
84 struct blkif_front_ring ring;
85 unsigned int evtchn, irq;
86 struct request_queue *rq;
87 struct work_struct work;
88 struct gnttab_free_callback callback;
89 struct blk_shadow shadow[BLK_RING_SIZE];
90 unsigned long shadow_free;
91 int feature_barrier;
Christian Limpach1d78d702008-04-02 10:54:04 -070092 int is_ready;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070093
94 /**
95 * The number of people holding this device open. We won't allow a
96 * hot-unplug unless this is 0.
97 */
98 int users;
99};
100
101static DEFINE_SPINLOCK(blkif_io_lock);
102
103#define MAXIMUM_OUTSTANDING_BLOCK_REQS \
104 (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
105#define GRANT_INVALID_REF 0
106
107#define PARTS_PER_DISK 16
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700108#define PARTS_PER_EXT_DISK 256
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700109
110#define BLKIF_MAJOR(dev) ((dev)>>8)
111#define BLKIF_MINOR(dev) ((dev) & 0xff)
112
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700113#define EXT_SHIFT 28
114#define EXTENDED (1<<EXT_SHIFT)
115#define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
116#define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700117
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700118#define DEV_NAME "xvd" /* name in /dev */
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700119
120static int get_id_from_freelist(struct blkfront_info *info)
121{
122 unsigned long free = info->shadow_free;
123 BUG_ON(free > BLK_RING_SIZE);
124 info->shadow_free = info->shadow[free].req.id;
125 info->shadow[free].req.id = 0x0fffffee; /* debug */
126 return free;
127}
128
129static void add_id_to_freelist(struct blkfront_info *info,
130 unsigned long id)
131{
132 info->shadow[id].req.id = info->shadow_free;
133 info->shadow[id].request = 0;
134 info->shadow_free = id;
135}
136
137static void blkif_restart_queue_callback(void *arg)
138{
139 struct blkfront_info *info = (struct blkfront_info *)arg;
140 schedule_work(&info->work);
141}
142
Harvey Harrisonafe42d72008-04-29 00:59:47 -0700143static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
Ian Campbell597592d2008-02-21 13:03:45 -0800144{
145 /* We don't have real geometry info, but let's at least return
146 values consistent with the size of the device */
147 sector_t nsect = get_capacity(bd->bd_disk);
148 sector_t cylinders = nsect;
149
150 hg->heads = 0xff;
151 hg->sectors = 0x3f;
152 sector_div(cylinders, hg->heads * hg->sectors);
153 hg->cylinders = cylinders;
154 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
155 hg->cylinders = 0xffff;
156 return 0;
157}
158
Al Viroa63c8482008-03-02 10:23:47 -0500159static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
Adrian Bunk62aa0052008-08-04 11:59:05 +0200160 unsigned command, unsigned long argument)
Christian Limpach440a01a2008-06-17 10:47:08 +0200161{
Al Viroa63c8482008-03-02 10:23:47 -0500162 struct blkfront_info *info = bdev->bd_disk->private_data;
Christian Limpach440a01a2008-06-17 10:47:08 +0200163 int i;
164
165 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
166 command, (long)argument);
167
168 switch (command) {
169 case CDROMMULTISESSION:
170 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
171 for (i = 0; i < sizeof(struct cdrom_multisession); i++)
172 if (put_user(0, (char __user *)(argument + i)))
173 return -EFAULT;
174 return 0;
175
176 case CDROM_GET_CAPABILITY: {
177 struct gendisk *gd = info->gd;
178 if (gd->flags & GENHD_FL_CD)
179 return 0;
180 return -EINVAL;
181 }
182
183 default:
184 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
185 command);*/
186 return -EINVAL; /* same return as native Linux */
187 }
188
189 return 0;
190}
191
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700192/*
193 * blkif_queue_request
194 *
195 * request block io
196 *
197 * id: for guest use only.
198 * operation: BLKIF_OP_{READ,WRITE,PROBE}
199 * buffer: buffer to read/write into. this should be a
200 * virtual address in the guest os.
201 */
202static int blkif_queue_request(struct request *req)
203{
204 struct blkfront_info *info = req->rq_disk->private_data;
205 unsigned long buffer_mfn;
206 struct blkif_request *ring_req;
NeilBrown5705f702007-09-25 12:35:59 +0200207 struct req_iterator iter;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700208 struct bio_vec *bvec;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700209 unsigned long id;
210 unsigned int fsect, lsect;
211 int ref;
212 grant_ref_t gref_head;
213
214 if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
215 return 1;
216
217 if (gnttab_alloc_grant_references(
218 BLKIF_MAX_SEGMENTS_PER_REQUEST, &gref_head) < 0) {
219 gnttab_request_free_callback(
220 &info->callback,
221 blkif_restart_queue_callback,
222 info,
223 BLKIF_MAX_SEGMENTS_PER_REQUEST);
224 return 1;
225 }
226
227 /* Fill out a communications ring structure. */
228 ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
229 id = get_id_from_freelist(info);
230 info->shadow[id].request = (unsigned long)req;
231
232 ring_req->id = id;
233 ring_req->sector_number = (blkif_sector_t)req->sector;
234 ring_req->handle = info->handle;
235
236 ring_req->operation = rq_data_dir(req) ?
237 BLKIF_OP_WRITE : BLKIF_OP_READ;
238 if (blk_barrier_rq(req))
239 ring_req->operation = BLKIF_OP_WRITE_BARRIER;
240
241 ring_req->nr_segments = 0;
NeilBrown5705f702007-09-25 12:35:59 +0200242 rq_for_each_segment(bvec, req, iter) {
Jens Axboe6c92e692007-08-16 13:43:12 +0200243 BUG_ON(ring_req->nr_segments == BLKIF_MAX_SEGMENTS_PER_REQUEST);
244 buffer_mfn = pfn_to_mfn(page_to_pfn(bvec->bv_page));
245 fsect = bvec->bv_offset >> 9;
246 lsect = fsect + (bvec->bv_len >> 9) - 1;
247 /* install a grant reference. */
248 ref = gnttab_claim_grant_reference(&gref_head);
249 BUG_ON(ref == -ENOSPC);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700250
Jens Axboe6c92e692007-08-16 13:43:12 +0200251 gnttab_grant_foreign_access_ref(
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700252 ref,
253 info->xbdev->otherend_id,
254 buffer_mfn,
255 rq_data_dir(req) );
256
Jens Axboe6c92e692007-08-16 13:43:12 +0200257 info->shadow[id].frame[ring_req->nr_segments] =
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700258 mfn_to_pfn(buffer_mfn);
259
Jens Axboe6c92e692007-08-16 13:43:12 +0200260 ring_req->seg[ring_req->nr_segments] =
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700261 (struct blkif_request_segment) {
262 .gref = ref,
263 .first_sect = fsect,
264 .last_sect = lsect };
265
Jens Axboe6c92e692007-08-16 13:43:12 +0200266 ring_req->nr_segments++;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700267 }
268
269 info->ring.req_prod_pvt++;
270
271 /* Keep a private copy so we can reissue requests when recovering. */
272 info->shadow[id].req = *ring_req;
273
274 gnttab_free_grant_references(gref_head);
275
276 return 0;
277}
278
279
280static inline void flush_requests(struct blkfront_info *info)
281{
282 int notify;
283
284 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify);
285
286 if (notify)
287 notify_remote_via_irq(info->irq);
288}
289
290/*
291 * do_blkif_request
292 * read a block; request is in a request queue
293 */
Jens Axboe165125e2007-07-24 09:28:11 +0200294static void do_blkif_request(struct request_queue *rq)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700295{
296 struct blkfront_info *info = NULL;
297 struct request *req;
298 int queued;
299
300 pr_debug("Entered do_blkif_request\n");
301
302 queued = 0;
303
304 while ((req = elv_next_request(rq)) != NULL) {
305 info = req->rq_disk->private_data;
306 if (!blk_fs_request(req)) {
307 end_request(req, 0);
308 continue;
309 }
310
311 if (RING_FULL(&info->ring))
312 goto wait;
313
314 pr_debug("do_blk_req %p: cmd %p, sec %lx, "
315 "(%u/%li) buffer:%p [%s]\n",
316 req, req->cmd, (unsigned long)req->sector,
317 req->current_nr_sectors,
318 req->nr_sectors, req->buffer,
319 rq_data_dir(req) ? "write" : "read");
320
321
322 blkdev_dequeue_request(req);
323 if (blkif_queue_request(req)) {
324 blk_requeue_request(rq, req);
325wait:
326 /* Avoid pointless unplugs. */
327 blk_stop_queue(rq);
328 break;
329 }
330
331 queued++;
332 }
333
334 if (queued != 0)
335 flush_requests(info);
336}
337
338static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
339{
Jens Axboe165125e2007-07-24 09:28:11 +0200340 struct request_queue *rq;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700341
342 rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
343 if (rq == NULL)
344 return -1;
345
346 elevator_init(rq, "noop");
347
348 /* Hard sector size and max sectors impersonate the equiv. hardware. */
349 blk_queue_hardsect_size(rq, sector_size);
350 blk_queue_max_sectors(rq, 512);
351
352 /* Each segment in a request is up to an aligned page in size. */
353 blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
354 blk_queue_max_segment_size(rq, PAGE_SIZE);
355
356 /* Ensure a merged request will fit in a single I/O ring slot. */
357 blk_queue_max_phys_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST);
358 blk_queue_max_hw_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST);
359
360 /* Make sure buffer addresses are sector-aligned. */
361 blk_queue_dma_alignment(rq, 511);
362
Ian Campbell1c91fe12008-06-17 10:47:08 +0200363 /* Make sure we don't use bounce buffers. */
364 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
365
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700366 gd->queue = rq;
367
368 return 0;
369}
370
371
372static int xlvbd_barrier(struct blkfront_info *info)
373{
374 int err;
375
376 err = blk_queue_ordered(info->rq,
377 info->feature_barrier ? QUEUE_ORDERED_DRAIN : QUEUE_ORDERED_NONE,
378 NULL);
379
380 if (err)
381 return err;
382
383 printk(KERN_INFO "blkfront: %s: barriers %s\n",
384 info->gd->disk_name,
385 info->feature_barrier ? "enabled" : "disabled");
386 return 0;
387}
388
389
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700390static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
391 struct blkfront_info *info,
392 u16 vdisk_info, u16 sector_size)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700393{
394 struct gendisk *gd;
395 int nr_minors = 1;
396 int err = -ENODEV;
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700397 unsigned int offset;
398 int minor;
399 int nr_parts;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700400
401 BUG_ON(info->gd != NULL);
402 BUG_ON(info->rq != NULL);
403
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700404 if ((info->vdevice>>EXT_SHIFT) > 1) {
405 /* this is above the extended range; something is wrong */
406 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice);
407 return -ENODEV;
408 }
409
410 if (!VDEV_IS_EXTENDED(info->vdevice)) {
411 minor = BLKIF_MINOR(info->vdevice);
412 nr_parts = PARTS_PER_DISK;
413 } else {
414 minor = BLKIF_MINOR_EXT(info->vdevice);
415 nr_parts = PARTS_PER_EXT_DISK;
416 }
417
418 if ((minor % nr_parts) == 0)
419 nr_minors = nr_parts;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700420
421 gd = alloc_disk(nr_minors);
422 if (gd == NULL)
423 goto out;
424
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700425 offset = minor / nr_parts;
426
427 if (nr_minors > 1) {
428 if (offset < 26)
429 sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset);
430 else
431 sprintf(gd->disk_name, "%s%c%c", DEV_NAME,
432 'a' + ((offset / 26)-1), 'a' + (offset % 26));
433 } else {
434 if (offset < 26)
435 sprintf(gd->disk_name, "%s%c%d", DEV_NAME,
436 'a' + offset,
437 minor & (nr_parts - 1));
438 else
439 sprintf(gd->disk_name, "%s%c%c%d", DEV_NAME,
440 'a' + ((offset / 26) - 1),
441 'a' + (offset % 26),
442 minor & (nr_parts - 1));
443 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700444
445 gd->major = XENVBD_MAJOR;
446 gd->first_minor = minor;
447 gd->fops = &xlvbd_block_fops;
448 gd->private_data = info;
449 gd->driverfs_dev = &(info->xbdev->dev);
450 set_capacity(gd, capacity);
451
452 if (xlvbd_init_blk_queue(gd, sector_size)) {
453 del_gendisk(gd);
454 goto out;
455 }
456
457 info->rq = gd->queue;
458 info->gd = gd;
459
460 if (info->feature_barrier)
461 xlvbd_barrier(info);
462
463 if (vdisk_info & VDISK_READONLY)
464 set_disk_ro(gd, 1);
465
466 if (vdisk_info & VDISK_REMOVABLE)
467 gd->flags |= GENHD_FL_REMOVABLE;
468
469 if (vdisk_info & VDISK_CDROM)
470 gd->flags |= GENHD_FL_CD;
471
472 return 0;
473
474 out:
475 return err;
476}
477
478static void kick_pending_request_queues(struct blkfront_info *info)
479{
480 if (!RING_FULL(&info->ring)) {
481 /* Re-enable calldowns. */
482 blk_start_queue(info->rq);
483 /* Kick things off immediately. */
484 do_blkif_request(info->rq);
485 }
486}
487
488static void blkif_restart_queue(struct work_struct *work)
489{
490 struct blkfront_info *info = container_of(work, struct blkfront_info, work);
491
492 spin_lock_irq(&blkif_io_lock);
493 if (info->connected == BLKIF_STATE_CONNECTED)
494 kick_pending_request_queues(info);
495 spin_unlock_irq(&blkif_io_lock);
496}
497
498static void blkif_free(struct blkfront_info *info, int suspend)
499{
500 /* Prevent new requests being issued until we fix things up. */
501 spin_lock_irq(&blkif_io_lock);
502 info->connected = suspend ?
503 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
504 /* No more blkif_request(). */
505 if (info->rq)
506 blk_stop_queue(info->rq);
507 /* No more gnttab callback work. */
508 gnttab_cancel_free_callback(&info->callback);
509 spin_unlock_irq(&blkif_io_lock);
510
511 /* Flush gnttab callback work. Must be done with no locks held. */
512 flush_scheduled_work();
513
514 /* Free resources associated with old device channel. */
515 if (info->ring_ref != GRANT_INVALID_REF) {
516 gnttab_end_foreign_access(info->ring_ref, 0,
517 (unsigned long)info->ring.sring);
518 info->ring_ref = GRANT_INVALID_REF;
519 info->ring.sring = NULL;
520 }
521 if (info->irq)
522 unbind_from_irqhandler(info->irq, info);
523 info->evtchn = info->irq = 0;
524
525}
526
527static void blkif_completion(struct blk_shadow *s)
528{
529 int i;
530 for (i = 0; i < s->req.nr_segments; i++)
531 gnttab_end_foreign_access(s->req.seg[i].gref, 0, 0UL);
532}
533
534static irqreturn_t blkif_interrupt(int irq, void *dev_id)
535{
536 struct request *req;
537 struct blkif_response *bret;
538 RING_IDX i, rp;
539 unsigned long flags;
540 struct blkfront_info *info = (struct blkfront_info *)dev_id;
Kiyoshi Uedaf530f0362007-12-11 17:47:36 -0500541 int error;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700542
543 spin_lock_irqsave(&blkif_io_lock, flags);
544
545 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
546 spin_unlock_irqrestore(&blkif_io_lock, flags);
547 return IRQ_HANDLED;
548 }
549
550 again:
551 rp = info->ring.sring->rsp_prod;
552 rmb(); /* Ensure we see queued responses up to 'rp'. */
553
554 for (i = info->ring.rsp_cons; i != rp; i++) {
555 unsigned long id;
556 int ret;
557
558 bret = RING_GET_RESPONSE(&info->ring, i);
559 id = bret->id;
560 req = (struct request *)info->shadow[id].request;
561
562 blkif_completion(&info->shadow[id]);
563
564 add_id_to_freelist(info, id);
565
Kiyoshi Uedaf530f0362007-12-11 17:47:36 -0500566 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700567 switch (bret->operation) {
568 case BLKIF_OP_WRITE_BARRIER:
569 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
570 printk(KERN_WARNING "blkfront: %s: write barrier op failed\n",
571 info->gd->disk_name);
Kiyoshi Uedaf530f0362007-12-11 17:47:36 -0500572 error = -EOPNOTSUPP;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700573 info->feature_barrier = 0;
574 xlvbd_barrier(info);
575 }
576 /* fall through */
577 case BLKIF_OP_READ:
578 case BLKIF_OP_WRITE:
579 if (unlikely(bret->status != BLKIF_RSP_OKAY))
580 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
581 "request: %x\n", bret->status);
582
Kiyoshi Uedaf530f0362007-12-11 17:47:36 -0500583 ret = __blk_end_request(req, error, blk_rq_bytes(req));
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700584 BUG_ON(ret);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700585 break;
586 default:
587 BUG();
588 }
589 }
590
591 info->ring.rsp_cons = i;
592
593 if (i != info->ring.req_prod_pvt) {
594 int more_to_do;
595 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
596 if (more_to_do)
597 goto again;
598 } else
599 info->ring.sring->rsp_event = i + 1;
600
601 kick_pending_request_queues(info);
602
603 spin_unlock_irqrestore(&blkif_io_lock, flags);
604
605 return IRQ_HANDLED;
606}
607
608
609static int setup_blkring(struct xenbus_device *dev,
610 struct blkfront_info *info)
611{
612 struct blkif_sring *sring;
613 int err;
614
615 info->ring_ref = GRANT_INVALID_REF;
616
Ian Campbella144ff02008-06-17 10:47:08 +0200617 sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700618 if (!sring) {
619 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
620 return -ENOMEM;
621 }
622 SHARED_RING_INIT(sring);
623 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
624
625 err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
626 if (err < 0) {
627 free_page((unsigned long)sring);
628 info->ring.sring = NULL;
629 goto fail;
630 }
631 info->ring_ref = err;
632
633 err = xenbus_alloc_evtchn(dev, &info->evtchn);
634 if (err)
635 goto fail;
636
637 err = bind_evtchn_to_irqhandler(info->evtchn,
638 blkif_interrupt,
639 IRQF_SAMPLE_RANDOM, "blkif", info);
640 if (err <= 0) {
641 xenbus_dev_fatal(dev, err,
642 "bind_evtchn_to_irqhandler failed");
643 goto fail;
644 }
645 info->irq = err;
646
647 return 0;
648fail:
649 blkif_free(info, 0);
650 return err;
651}
652
653
654/* Common code used when first setting up, and when resuming. */
655static int talk_to_backend(struct xenbus_device *dev,
656 struct blkfront_info *info)
657{
658 const char *message = NULL;
659 struct xenbus_transaction xbt;
660 int err;
661
662 /* Create shared ring, alloc event channel. */
663 err = setup_blkring(dev, info);
664 if (err)
665 goto out;
666
667again:
668 err = xenbus_transaction_start(&xbt);
669 if (err) {
670 xenbus_dev_fatal(dev, err, "starting transaction");
671 goto destroy_blkring;
672 }
673
674 err = xenbus_printf(xbt, dev->nodename,
675 "ring-ref", "%u", info->ring_ref);
676 if (err) {
677 message = "writing ring-ref";
678 goto abort_transaction;
679 }
680 err = xenbus_printf(xbt, dev->nodename,
681 "event-channel", "%u", info->evtchn);
682 if (err) {
683 message = "writing event-channel";
684 goto abort_transaction;
685 }
Markus Armbruster3e334232008-04-02 10:54:02 -0700686 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
687 XEN_IO_PROTO_ABI_NATIVE);
688 if (err) {
689 message = "writing protocol";
690 goto abort_transaction;
691 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700692
693 err = xenbus_transaction_end(xbt, 0);
694 if (err) {
695 if (err == -EAGAIN)
696 goto again;
697 xenbus_dev_fatal(dev, err, "completing transaction");
698 goto destroy_blkring;
699 }
700
701 xenbus_switch_state(dev, XenbusStateInitialised);
702
703 return 0;
704
705 abort_transaction:
706 xenbus_transaction_end(xbt, 1);
707 if (message)
708 xenbus_dev_fatal(dev, err, "%s", message);
709 destroy_blkring:
710 blkif_free(info, 0);
711 out:
712 return err;
713}
714
715
716/**
717 * Entry point to this code when a new device is created. Allocate the basic
718 * structures and the ring buffer for communication with the backend, and
719 * inform the backend of the appropriate details for those. Switch to
720 * Initialised state.
721 */
722static int blkfront_probe(struct xenbus_device *dev,
723 const struct xenbus_device_id *id)
724{
725 int err, vdevice, i;
726 struct blkfront_info *info;
727
728 /* FIXME: Use dynamic device id if this is not set. */
729 err = xenbus_scanf(XBT_NIL, dev->nodename,
730 "virtual-device", "%i", &vdevice);
731 if (err != 1) {
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700732 /* go looking in the extended area instead */
733 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext",
734 "%i", &vdevice);
735 if (err != 1) {
736 xenbus_dev_fatal(dev, err, "reading virtual-device");
737 return err;
738 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700739 }
740
741 info = kzalloc(sizeof(*info), GFP_KERNEL);
742 if (!info) {
743 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
744 return -ENOMEM;
745 }
746
747 info->xbdev = dev;
748 info->vdevice = vdevice;
749 info->connected = BLKIF_STATE_DISCONNECTED;
750 INIT_WORK(&info->work, blkif_restart_queue);
751
752 for (i = 0; i < BLK_RING_SIZE; i++)
753 info->shadow[i].req.id = i+1;
754 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
755
756 /* Front end dir is a number, which is used as the id. */
757 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
758 dev->dev.driver_data = info;
759
760 err = talk_to_backend(dev, info);
761 if (err) {
762 kfree(info);
763 dev->dev.driver_data = NULL;
764 return err;
765 }
766
767 return 0;
768}
769
770
771static int blkif_recover(struct blkfront_info *info)
772{
773 int i;
774 struct blkif_request *req;
775 struct blk_shadow *copy;
776 int j;
777
778 /* Stage 1: Make a safe copy of the shadow state. */
Ian Campbella144ff02008-06-17 10:47:08 +0200779 copy = kmalloc(sizeof(info->shadow),
780 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700781 if (!copy)
782 return -ENOMEM;
783 memcpy(copy, info->shadow, sizeof(info->shadow));
784
785 /* Stage 2: Set up free list. */
786 memset(&info->shadow, 0, sizeof(info->shadow));
787 for (i = 0; i < BLK_RING_SIZE; i++)
788 info->shadow[i].req.id = i+1;
789 info->shadow_free = info->ring.req_prod_pvt;
790 info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
791
792 /* Stage 3: Find pending requests and requeue them. */
793 for (i = 0; i < BLK_RING_SIZE; i++) {
794 /* Not in use? */
795 if (copy[i].request == 0)
796 continue;
797
798 /* Grab a request slot and copy shadow state into it. */
799 req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
800 *req = copy[i].req;
801
802 /* We get a new request id, and must reset the shadow state. */
803 req->id = get_id_from_freelist(info);
804 memcpy(&info->shadow[req->id], &copy[i], sizeof(copy[i]));
805
806 /* Rewrite any grant references invalidated by susp/resume. */
807 for (j = 0; j < req->nr_segments; j++)
808 gnttab_grant_foreign_access_ref(
809 req->seg[j].gref,
810 info->xbdev->otherend_id,
811 pfn_to_mfn(info->shadow[req->id].frame[j]),
812 rq_data_dir(
813 (struct request *)
814 info->shadow[req->id].request));
815 info->shadow[req->id].req = *req;
816
817 info->ring.req_prod_pvt++;
818 }
819
820 kfree(copy);
821
822 xenbus_switch_state(info->xbdev, XenbusStateConnected);
823
824 spin_lock_irq(&blkif_io_lock);
825
826 /* Now safe for us to use the shared ring */
827 info->connected = BLKIF_STATE_CONNECTED;
828
829 /* Send off requeued requests */
830 flush_requests(info);
831
832 /* Kick any other new requests queued since we resumed */
833 kick_pending_request_queues(info);
834
835 spin_unlock_irq(&blkif_io_lock);
836
837 return 0;
838}
839
840/**
841 * We are reconnecting to the backend, due to a suspend/resume, or a backend
842 * driver restart. We tear down our blkif structure and recreate it, but
843 * leave the device-layer structures intact so that this is transparent to the
844 * rest of the kernel.
845 */
846static int blkfront_resume(struct xenbus_device *dev)
847{
848 struct blkfront_info *info = dev->dev.driver_data;
849 int err;
850
851 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
852
853 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
854
855 err = talk_to_backend(dev, info);
856 if (info->connected == BLKIF_STATE_SUSPENDED && !err)
857 err = blkif_recover(info);
858
859 return err;
860}
861
862
863/*
864 * Invoked when the backend is finally 'ready' (and has told produced
865 * the details about the physical device - #sectors, size, etc).
866 */
867static void blkfront_connect(struct blkfront_info *info)
868{
869 unsigned long long sectors;
870 unsigned long sector_size;
871 unsigned int binfo;
872 int err;
873
874 if ((info->connected == BLKIF_STATE_CONNECTED) ||
875 (info->connected == BLKIF_STATE_SUSPENDED) )
876 return;
877
878 dev_dbg(&info->xbdev->dev, "%s:%s.\n",
879 __func__, info->xbdev->otherend);
880
881 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
882 "sectors", "%llu", &sectors,
883 "info", "%u", &binfo,
884 "sector-size", "%lu", &sector_size,
885 NULL);
886 if (err) {
887 xenbus_dev_fatal(info->xbdev, err,
888 "reading backend fields at %s",
889 info->xbdev->otherend);
890 return;
891 }
892
893 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
894 "feature-barrier", "%lu", &info->feature_barrier,
895 NULL);
896 if (err)
897 info->feature_barrier = 0;
898
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700899 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700900 if (err) {
901 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
902 info->xbdev->otherend);
903 return;
904 }
905
906 xenbus_switch_state(info->xbdev, XenbusStateConnected);
907
908 /* Kick pending requests. */
909 spin_lock_irq(&blkif_io_lock);
910 info->connected = BLKIF_STATE_CONNECTED;
911 kick_pending_request_queues(info);
912 spin_unlock_irq(&blkif_io_lock);
913
914 add_disk(info->gd);
Christian Limpach1d78d702008-04-02 10:54:04 -0700915
916 info->is_ready = 1;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700917}
918
919/**
920 * Handle the change of state of the backend to Closing. We must delete our
921 * device-layer structures now, to ensure that writes are flushed through to
922 * the backend. Once is this done, we can switch to Closed in
923 * acknowledgement.
924 */
925static void blkfront_closing(struct xenbus_device *dev)
926{
927 struct blkfront_info *info = dev->dev.driver_data;
928 unsigned long flags;
929
930 dev_dbg(&dev->dev, "blkfront_closing: %s removed\n", dev->nodename);
931
932 if (info->rq == NULL)
933 goto out;
934
935 spin_lock_irqsave(&blkif_io_lock, flags);
936
937 del_gendisk(info->gd);
938
939 /* No more blkif_request(). */
940 blk_stop_queue(info->rq);
941
942 /* No more gnttab callback work. */
943 gnttab_cancel_free_callback(&info->callback);
944 spin_unlock_irqrestore(&blkif_io_lock, flags);
945
946 /* Flush gnttab callback work. Must be done with no locks held. */
947 flush_scheduled_work();
948
949 blk_cleanup_queue(info->rq);
950 info->rq = NULL;
951
952 out:
953 xenbus_frontend_closed(dev);
954}
955
956/**
957 * Callback received when the backend's state changes.
958 */
959static void backend_changed(struct xenbus_device *dev,
960 enum xenbus_state backend_state)
961{
962 struct blkfront_info *info = dev->dev.driver_data;
963 struct block_device *bd;
964
965 dev_dbg(&dev->dev, "blkfront:backend_changed.\n");
966
967 switch (backend_state) {
968 case XenbusStateInitialising:
969 case XenbusStateInitWait:
970 case XenbusStateInitialised:
971 case XenbusStateUnknown:
972 case XenbusStateClosed:
973 break;
974
975 case XenbusStateConnected:
976 blkfront_connect(info);
977 break;
978
979 case XenbusStateClosing:
Jeremy Fitzhardinge53f0e8a2008-04-02 10:54:03 -0700980 bd = bdget_disk(info->gd, 0);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700981 if (bd == NULL)
982 xenbus_dev_fatal(dev, -ENODEV, "bdget failed");
983
984 mutex_lock(&bd->bd_mutex);
985 if (info->users > 0)
986 xenbus_dev_error(dev, -EBUSY,
987 "Device in use; refusing to close");
988 else
989 blkfront_closing(dev);
990 mutex_unlock(&bd->bd_mutex);
991 bdput(bd);
992 break;
993 }
994}
995
996static int blkfront_remove(struct xenbus_device *dev)
997{
998 struct blkfront_info *info = dev->dev.driver_data;
999
1000 dev_dbg(&dev->dev, "blkfront_remove: %s removed\n", dev->nodename);
1001
1002 blkif_free(info, 0);
1003
1004 kfree(info);
1005
1006 return 0;
1007}
1008
Christian Limpach1d78d702008-04-02 10:54:04 -07001009static int blkfront_is_ready(struct xenbus_device *dev)
1010{
1011 struct blkfront_info *info = dev->dev.driver_data;
1012
1013 return info->is_ready;
1014}
1015
Al Viroa63c8482008-03-02 10:23:47 -05001016static int blkif_open(struct block_device *bdev, fmode_t mode)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001017{
Al Viroa63c8482008-03-02 10:23:47 -05001018 struct blkfront_info *info = bdev->bd_disk->private_data;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001019 info->users++;
1020 return 0;
1021}
1022
Al Viroa63c8482008-03-02 10:23:47 -05001023static int blkif_release(struct gendisk *disk, fmode_t mode)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001024{
Al Viroa63c8482008-03-02 10:23:47 -05001025 struct blkfront_info *info = disk->private_data;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001026 info->users--;
1027 if (info->users == 0) {
1028 /* Check whether we have been instructed to close. We will
1029 have ignored this request initially, as the device was
1030 still mounted. */
1031 struct xenbus_device *dev = info->xbdev;
1032 enum xenbus_state state = xenbus_read_driver_state(dev->otherend);
1033
Wim Colgate04c06352008-06-17 10:47:08 +02001034 if (state == XenbusStateClosing && info->is_ready)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001035 blkfront_closing(dev);
1036 }
1037 return 0;
1038}
1039
1040static struct block_device_operations xlvbd_block_fops =
1041{
1042 .owner = THIS_MODULE,
Al Viroa63c8482008-03-02 10:23:47 -05001043 .open = blkif_open,
1044 .release = blkif_release,
Ian Campbell597592d2008-02-21 13:03:45 -08001045 .getgeo = blkif_getgeo,
Al Viroa63c8482008-03-02 10:23:47 -05001046 .locked_ioctl = blkif_ioctl,
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001047};
1048
1049
1050static struct xenbus_device_id blkfront_ids[] = {
1051 { "vbd" },
1052 { "" }
1053};
1054
1055static struct xenbus_driver blkfront = {
1056 .name = "vbd",
1057 .owner = THIS_MODULE,
1058 .ids = blkfront_ids,
1059 .probe = blkfront_probe,
1060 .remove = blkfront_remove,
1061 .resume = blkfront_resume,
1062 .otherend_changed = backend_changed,
Christian Limpach1d78d702008-04-02 10:54:04 -07001063 .is_ready = blkfront_is_ready,
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001064};
1065
1066static int __init xlblk_init(void)
1067{
Jeremy Fitzhardinge6e833582008-08-19 13:16:17 -07001068 if (!xen_domain())
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001069 return -ENODEV;
1070
1071 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
1072 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
1073 XENVBD_MAJOR, DEV_NAME);
1074 return -ENODEV;
1075 }
1076
1077 return xenbus_register_frontend(&blkfront);
1078}
1079module_init(xlblk_init);
1080
1081
Jan Beulich5a60d0c2008-06-17 10:47:08 +02001082static void __exit xlblk_exit(void)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001083{
1084 return xenbus_unregister_driver(&blkfront);
1085}
1086module_exit(xlblk_exit);
1087
1088MODULE_DESCRIPTION("Xen virtual block device frontend");
1089MODULE_LICENSE("GPL");
1090MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
Mark McLoughlind2f0c522008-04-02 10:54:05 -07001091MODULE_ALIAS("xen:vbd");
Mark McLoughlin4f93f09b2008-04-02 10:54:06 -07001092MODULE_ALIAS("xenblk");