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rbd: fix error paths in rbd_img_request_fill()
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / block / xen-blkfront.c
1 /*
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>
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>
46 #include <linux/bitmap.h>
47 #include <linux/list.h>
48
49 #include <xen/xen.h>
50 #include <xen/xenbus.h>
51 #include <xen/grant_table.h>
52 #include <xen/events.h>
53 #include <xen/page.h>
54 #include <xen/platform_pci.h>
55
56 #include <xen/interface/grant_table.h>
57 #include <xen/interface/io/blkif.h>
58 #include <xen/interface/io/protocols.h>
59
60 #include <asm/xen/hypervisor.h>
61
62 enum blkif_state {
63 BLKIF_STATE_DISCONNECTED,
64 BLKIF_STATE_CONNECTED,
65 BLKIF_STATE_SUSPENDED,
66 };
67
68 struct grant {
69 grant_ref_t gref;
70 unsigned long pfn;
71 struct list_head node;
72 };
73
74 struct blk_shadow {
75 struct blkif_request req;
76 struct request *request;
77 struct grant *grants_used[BLKIF_MAX_SEGMENTS_PER_REQUEST];
78 struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
79 };
80
81 static DEFINE_MUTEX(blkfront_mutex);
82 static const struct block_device_operations xlvbd_block_fops;
83
84 #define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
85
86 /*
87 * We have one of these per vbd, whether ide, scsi or 'other'. They
88 * hang in private_data off the gendisk structure. We may end up
89 * putting all kinds of interesting stuff here :-)
90 */
91 struct blkfront_info
92 {
93 spinlock_t io_lock;
94 struct mutex mutex;
95 struct xenbus_device *xbdev;
96 struct gendisk *gd;
97 int vdevice;
98 blkif_vdev_t handle;
99 enum blkif_state connected;
100 int ring_ref;
101 struct blkif_front_ring ring;
102 unsigned int evtchn, irq;
103 struct request_queue *rq;
104 struct work_struct work;
105 struct gnttab_free_callback callback;
106 struct blk_shadow shadow[BLK_RING_SIZE];
107 struct list_head persistent_gnts;
108 unsigned int persistent_gnts_c;
109 unsigned long shadow_free;
110 unsigned int feature_flush;
111 unsigned int flush_op;
112 unsigned int feature_discard:1;
113 unsigned int feature_secdiscard:1;
114 unsigned int discard_granularity;
115 unsigned int discard_alignment;
116 unsigned int feature_persistent:1;
117 int is_ready;
118 };
119
120 static unsigned int nr_minors;
121 static unsigned long *minors;
122 static DEFINE_SPINLOCK(minor_lock);
123
124 #define MAXIMUM_OUTSTANDING_BLOCK_REQS \
125 (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
126 #define GRANT_INVALID_REF 0
127
128 #define PARTS_PER_DISK 16
129 #define PARTS_PER_EXT_DISK 256
130
131 #define BLKIF_MAJOR(dev) ((dev)>>8)
132 #define BLKIF_MINOR(dev) ((dev) & 0xff)
133
134 #define EXT_SHIFT 28
135 #define EXTENDED (1<<EXT_SHIFT)
136 #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
137 #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
138 #define EMULATED_HD_DISK_MINOR_OFFSET (0)
139 #define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256)
140 #define EMULATED_SD_DISK_MINOR_OFFSET (0)
141 #define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256)
142
143 #define DEV_NAME "xvd" /* name in /dev */
144
145 static int get_id_from_freelist(struct blkfront_info *info)
146 {
147 unsigned long free = info->shadow_free;
148 BUG_ON(free >= BLK_RING_SIZE);
149 info->shadow_free = info->shadow[free].req.u.rw.id;
150 info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
151 return free;
152 }
153
154 static int add_id_to_freelist(struct blkfront_info *info,
155 unsigned long id)
156 {
157 if (info->shadow[id].req.u.rw.id != id)
158 return -EINVAL;
159 if (info->shadow[id].request == NULL)
160 return -EINVAL;
161 info->shadow[id].req.u.rw.id = info->shadow_free;
162 info->shadow[id].request = NULL;
163 info->shadow_free = id;
164 return 0;
165 }
166
167 static int fill_grant_buffer(struct blkfront_info *info, int num)
168 {
169 struct page *granted_page;
170 struct grant *gnt_list_entry, *n;
171 int i = 0;
172
173 while(i < num) {
174 gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO);
175 if (!gnt_list_entry)
176 goto out_of_memory;
177
178 granted_page = alloc_page(GFP_NOIO);
179 if (!granted_page) {
180 kfree(gnt_list_entry);
181 goto out_of_memory;
182 }
183
184 gnt_list_entry->pfn = page_to_pfn(granted_page);
185 gnt_list_entry->gref = GRANT_INVALID_REF;
186 list_add(&gnt_list_entry->node, &info->persistent_gnts);
187 i++;
188 }
189
190 return 0;
191
192 out_of_memory:
193 list_for_each_entry_safe(gnt_list_entry, n,
194 &info->persistent_gnts, node) {
195 list_del(&gnt_list_entry->node);
196 __free_page(pfn_to_page(gnt_list_entry->pfn));
197 kfree(gnt_list_entry);
198 i--;
199 }
200 BUG_ON(i != 0);
201 return -ENOMEM;
202 }
203
204 static struct grant *get_grant(grant_ref_t *gref_head,
205 struct blkfront_info *info)
206 {
207 struct grant *gnt_list_entry;
208 unsigned long buffer_mfn;
209
210 BUG_ON(list_empty(&info->persistent_gnts));
211 gnt_list_entry = list_first_entry(&info->persistent_gnts, struct grant,
212 node);
213 list_del(&gnt_list_entry->node);
214
215 if (gnt_list_entry->gref != GRANT_INVALID_REF) {
216 info->persistent_gnts_c--;
217 return gnt_list_entry;
218 }
219
220 /* Assign a gref to this page */
221 gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
222 BUG_ON(gnt_list_entry->gref == -ENOSPC);
223 buffer_mfn = pfn_to_mfn(gnt_list_entry->pfn);
224 gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
225 info->xbdev->otherend_id,
226 buffer_mfn, 0);
227 return gnt_list_entry;
228 }
229
230 static const char *op_name(int op)
231 {
232 static const char *const names[] = {
233 [BLKIF_OP_READ] = "read",
234 [BLKIF_OP_WRITE] = "write",
235 [BLKIF_OP_WRITE_BARRIER] = "barrier",
236 [BLKIF_OP_FLUSH_DISKCACHE] = "flush",
237 [BLKIF_OP_DISCARD] = "discard" };
238
239 if (op < 0 || op >= ARRAY_SIZE(names))
240 return "unknown";
241
242 if (!names[op])
243 return "reserved";
244
245 return names[op];
246 }
247 static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
248 {
249 unsigned int end = minor + nr;
250 int rc;
251
252 if (end > nr_minors) {
253 unsigned long *bitmap, *old;
254
255 bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap),
256 GFP_KERNEL);
257 if (bitmap == NULL)
258 return -ENOMEM;
259
260 spin_lock(&minor_lock);
261 if (end > nr_minors) {
262 old = minors;
263 memcpy(bitmap, minors,
264 BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
265 minors = bitmap;
266 nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
267 } else
268 old = bitmap;
269 spin_unlock(&minor_lock);
270 kfree(old);
271 }
272
273 spin_lock(&minor_lock);
274 if (find_next_bit(minors, end, minor) >= end) {
275 bitmap_set(minors, minor, nr);
276 rc = 0;
277 } else
278 rc = -EBUSY;
279 spin_unlock(&minor_lock);
280
281 return rc;
282 }
283
284 static void xlbd_release_minors(unsigned int minor, unsigned int nr)
285 {
286 unsigned int end = minor + nr;
287
288 BUG_ON(end > nr_minors);
289 spin_lock(&minor_lock);
290 bitmap_clear(minors, minor, nr);
291 spin_unlock(&minor_lock);
292 }
293
294 static void blkif_restart_queue_callback(void *arg)
295 {
296 struct blkfront_info *info = (struct blkfront_info *)arg;
297 schedule_work(&info->work);
298 }
299
300 static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
301 {
302 /* We don't have real geometry info, but let's at least return
303 values consistent with the size of the device */
304 sector_t nsect = get_capacity(bd->bd_disk);
305 sector_t cylinders = nsect;
306
307 hg->heads = 0xff;
308 hg->sectors = 0x3f;
309 sector_div(cylinders, hg->heads * hg->sectors);
310 hg->cylinders = cylinders;
311 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
312 hg->cylinders = 0xffff;
313 return 0;
314 }
315
316 static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
317 unsigned command, unsigned long argument)
318 {
319 struct blkfront_info *info = bdev->bd_disk->private_data;
320 int i;
321
322 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
323 command, (long)argument);
324
325 switch (command) {
326 case CDROMMULTISESSION:
327 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
328 for (i = 0; i < sizeof(struct cdrom_multisession); i++)
329 if (put_user(0, (char __user *)(argument + i)))
330 return -EFAULT;
331 return 0;
332
333 case CDROM_GET_CAPABILITY: {
334 struct gendisk *gd = info->gd;
335 if (gd->flags & GENHD_FL_CD)
336 return 0;
337 return -EINVAL;
338 }
339
340 default:
341 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
342 command);*/
343 return -EINVAL; /* same return as native Linux */
344 }
345
346 return 0;
347 }
348
349 /*
350 * Generate a Xen blkfront IO request from a blk layer request. Reads
351 * and writes are handled as expected.
352 *
353 * @req: a request struct
354 */
355 static int blkif_queue_request(struct request *req)
356 {
357 struct blkfront_info *info = req->rq_disk->private_data;
358 struct blkif_request *ring_req;
359 unsigned long id;
360 unsigned int fsect, lsect;
361 int i, ref;
362
363 /*
364 * Used to store if we are able to queue the request by just using
365 * existing persistent grants, or if we have to get new grants,
366 * as there are not sufficiently many free.
367 */
368 bool new_persistent_gnts;
369 grant_ref_t gref_head;
370 struct grant *gnt_list_entry = NULL;
371 struct scatterlist *sg;
372
373 if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
374 return 1;
375
376 /* Check if we have enought grants to allocate a requests */
377 if (info->persistent_gnts_c < BLKIF_MAX_SEGMENTS_PER_REQUEST) {
378 new_persistent_gnts = 1;
379 if (gnttab_alloc_grant_references(
380 BLKIF_MAX_SEGMENTS_PER_REQUEST - info->persistent_gnts_c,
381 &gref_head) < 0) {
382 gnttab_request_free_callback(
383 &info->callback,
384 blkif_restart_queue_callback,
385 info,
386 BLKIF_MAX_SEGMENTS_PER_REQUEST);
387 return 1;
388 }
389 } else
390 new_persistent_gnts = 0;
391
392 /* Fill out a communications ring structure. */
393 ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
394 id = get_id_from_freelist(info);
395 info->shadow[id].request = req;
396
397 ring_req->u.rw.id = id;
398 ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req);
399 ring_req->u.rw.handle = info->handle;
400
401 ring_req->operation = rq_data_dir(req) ?
402 BLKIF_OP_WRITE : BLKIF_OP_READ;
403
404 if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
405 /*
406 * Ideally we can do an unordered flush-to-disk. In case the
407 * backend onlysupports barriers, use that. A barrier request
408 * a superset of FUA, so we can implement it the same
409 * way. (It's also a FLUSH+FUA, since it is
410 * guaranteed ordered WRT previous writes.)
411 */
412 ring_req->operation = info->flush_op;
413 }
414
415 if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) {
416 /* id, sector_number and handle are set above. */
417 ring_req->operation = BLKIF_OP_DISCARD;
418 ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
419 if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard)
420 ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;
421 else
422 ring_req->u.discard.flag = 0;
423 } else {
424 ring_req->u.rw.nr_segments = blk_rq_map_sg(req->q, req,
425 info->shadow[id].sg);
426 BUG_ON(ring_req->u.rw.nr_segments >
427 BLKIF_MAX_SEGMENTS_PER_REQUEST);
428
429 for_each_sg(info->shadow[id].sg, sg, ring_req->u.rw.nr_segments, i) {
430 fsect = sg->offset >> 9;
431 lsect = fsect + (sg->length >> 9) - 1;
432
433 gnt_list_entry = get_grant(&gref_head, info);
434 ref = gnt_list_entry->gref;
435
436 info->shadow[id].grants_used[i] = gnt_list_entry;
437
438 if (rq_data_dir(req)) {
439 char *bvec_data;
440 void *shared_data;
441
442 BUG_ON(sg->offset + sg->length > PAGE_SIZE);
443
444 shared_data = kmap_atomic(
445 pfn_to_page(gnt_list_entry->pfn));
446 bvec_data = kmap_atomic(sg_page(sg));
447
448 /*
449 * this does not wipe data stored outside the
450 * range sg->offset..sg->offset+sg->length.
451 * Therefore, blkback *could* see data from
452 * previous requests. This is OK as long as
453 * persistent grants are shared with just one
454 * domain. It may need refactoring if this
455 * changes
456 */
457 memcpy(shared_data + sg->offset,
458 bvec_data + sg->offset,
459 sg->length);
460
461 kunmap_atomic(bvec_data);
462 kunmap_atomic(shared_data);
463 }
464
465 ring_req->u.rw.seg[i] =
466 (struct blkif_request_segment) {
467 .gref = ref,
468 .first_sect = fsect,
469 .last_sect = lsect };
470 }
471 }
472
473 info->ring.req_prod_pvt++;
474
475 /* Keep a private copy so we can reissue requests when recovering. */
476 info->shadow[id].req = *ring_req;
477
478 if (new_persistent_gnts)
479 gnttab_free_grant_references(gref_head);
480
481 return 0;
482 }
483
484
485 static inline void flush_requests(struct blkfront_info *info)
486 {
487 int notify;
488
489 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify);
490
491 if (notify)
492 notify_remote_via_irq(info->irq);
493 }
494
495 /*
496 * do_blkif_request
497 * read a block; request is in a request queue
498 */
499 static void do_blkif_request(struct request_queue *rq)
500 {
501 struct blkfront_info *info = NULL;
502 struct request *req;
503 int queued;
504
505 pr_debug("Entered do_blkif_request\n");
506
507 queued = 0;
508
509 while ((req = blk_peek_request(rq)) != NULL) {
510 info = req->rq_disk->private_data;
511
512 if (RING_FULL(&info->ring))
513 goto wait;
514
515 blk_start_request(req);
516
517 if ((req->cmd_type != REQ_TYPE_FS) ||
518 ((req->cmd_flags & (REQ_FLUSH | REQ_FUA)) &&
519 !info->flush_op)) {
520 __blk_end_request_all(req, -EIO);
521 continue;
522 }
523
524 pr_debug("do_blk_req %p: cmd %p, sec %lx, "
525 "(%u/%u) buffer:%p [%s]\n",
526 req, req->cmd, (unsigned long)blk_rq_pos(req),
527 blk_rq_cur_sectors(req), blk_rq_sectors(req),
528 req->buffer, rq_data_dir(req) ? "write" : "read");
529
530 if (blkif_queue_request(req)) {
531 blk_requeue_request(rq, req);
532 wait:
533 /* Avoid pointless unplugs. */
534 blk_stop_queue(rq);
535 break;
536 }
537
538 queued++;
539 }
540
541 if (queued != 0)
542 flush_requests(info);
543 }
544
545 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
546 {
547 struct request_queue *rq;
548 struct blkfront_info *info = gd->private_data;
549
550 rq = blk_init_queue(do_blkif_request, &info->io_lock);
551 if (rq == NULL)
552 return -1;
553
554 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
555
556 if (info->feature_discard) {
557 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
558 blk_queue_max_discard_sectors(rq, get_capacity(gd));
559 rq->limits.discard_granularity = info->discard_granularity;
560 rq->limits.discard_alignment = info->discard_alignment;
561 if (info->feature_secdiscard)
562 queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, rq);
563 }
564
565 /* Hard sector size and max sectors impersonate the equiv. hardware. */
566 blk_queue_logical_block_size(rq, sector_size);
567 blk_queue_max_hw_sectors(rq, 512);
568
569 /* Each segment in a request is up to an aligned page in size. */
570 blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
571 blk_queue_max_segment_size(rq, PAGE_SIZE);
572
573 /* Ensure a merged request will fit in a single I/O ring slot. */
574 blk_queue_max_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST);
575
576 /* Make sure buffer addresses are sector-aligned. */
577 blk_queue_dma_alignment(rq, 511);
578
579 /* Make sure we don't use bounce buffers. */
580 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
581
582 gd->queue = rq;
583
584 return 0;
585 }
586
587
588 static void xlvbd_flush(struct blkfront_info *info)
589 {
590 blk_queue_flush(info->rq, info->feature_flush);
591 printk(KERN_INFO "blkfront: %s: %s: %s %s\n",
592 info->gd->disk_name,
593 info->flush_op == BLKIF_OP_WRITE_BARRIER ?
594 "barrier" : (info->flush_op == BLKIF_OP_FLUSH_DISKCACHE ?
595 "flush diskcache" : "barrier or flush"),
596 info->feature_flush ? "enabled" : "disabled",
597 info->feature_persistent ? "using persistent grants" : "");
598 }
599
600 static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
601 {
602 int major;
603 major = BLKIF_MAJOR(vdevice);
604 *minor = BLKIF_MINOR(vdevice);
605 switch (major) {
606 case XEN_IDE0_MAJOR:
607 *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET;
608 *minor = ((*minor / 64) * PARTS_PER_DISK) +
609 EMULATED_HD_DISK_MINOR_OFFSET;
610 break;
611 case XEN_IDE1_MAJOR:
612 *offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET;
613 *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) +
614 EMULATED_HD_DISK_MINOR_OFFSET;
615 break;
616 case XEN_SCSI_DISK0_MAJOR:
617 *offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET;
618 *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET;
619 break;
620 case XEN_SCSI_DISK1_MAJOR:
621 case XEN_SCSI_DISK2_MAJOR:
622 case XEN_SCSI_DISK3_MAJOR:
623 case XEN_SCSI_DISK4_MAJOR:
624 case XEN_SCSI_DISK5_MAJOR:
625 case XEN_SCSI_DISK6_MAJOR:
626 case XEN_SCSI_DISK7_MAJOR:
627 *offset = (*minor / PARTS_PER_DISK) +
628 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) +
629 EMULATED_SD_DISK_NAME_OFFSET;
630 *minor = *minor +
631 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) +
632 EMULATED_SD_DISK_MINOR_OFFSET;
633 break;
634 case XEN_SCSI_DISK8_MAJOR:
635 case XEN_SCSI_DISK9_MAJOR:
636 case XEN_SCSI_DISK10_MAJOR:
637 case XEN_SCSI_DISK11_MAJOR:
638 case XEN_SCSI_DISK12_MAJOR:
639 case XEN_SCSI_DISK13_MAJOR:
640 case XEN_SCSI_DISK14_MAJOR:
641 case XEN_SCSI_DISK15_MAJOR:
642 *offset = (*minor / PARTS_PER_DISK) +
643 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) +
644 EMULATED_SD_DISK_NAME_OFFSET;
645 *minor = *minor +
646 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) +
647 EMULATED_SD_DISK_MINOR_OFFSET;
648 break;
649 case XENVBD_MAJOR:
650 *offset = *minor / PARTS_PER_DISK;
651 break;
652 default:
653 printk(KERN_WARNING "blkfront: your disk configuration is "
654 "incorrect, please use an xvd device instead\n");
655 return -ENODEV;
656 }
657 return 0;
658 }
659
660 static char *encode_disk_name(char *ptr, unsigned int n)
661 {
662 if (n >= 26)
663 ptr = encode_disk_name(ptr, n / 26 - 1);
664 *ptr = 'a' + n % 26;
665 return ptr + 1;
666 }
667
668 static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
669 struct blkfront_info *info,
670 u16 vdisk_info, u16 sector_size)
671 {
672 struct gendisk *gd;
673 int nr_minors = 1;
674 int err;
675 unsigned int offset;
676 int minor;
677 int nr_parts;
678 char *ptr;
679
680 BUG_ON(info->gd != NULL);
681 BUG_ON(info->rq != NULL);
682
683 if ((info->vdevice>>EXT_SHIFT) > 1) {
684 /* this is above the extended range; something is wrong */
685 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice);
686 return -ENODEV;
687 }
688
689 if (!VDEV_IS_EXTENDED(info->vdevice)) {
690 err = xen_translate_vdev(info->vdevice, &minor, &offset);
691 if (err)
692 return err;
693 nr_parts = PARTS_PER_DISK;
694 } else {
695 minor = BLKIF_MINOR_EXT(info->vdevice);
696 nr_parts = PARTS_PER_EXT_DISK;
697 offset = minor / nr_parts;
698 if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4)
699 printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with "
700 "emulated IDE disks,\n\t choose an xvd device name"
701 "from xvde on\n", info->vdevice);
702 }
703 if (minor >> MINORBITS) {
704 pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n",
705 info->vdevice, minor);
706 return -ENODEV;
707 }
708
709 if ((minor % nr_parts) == 0)
710 nr_minors = nr_parts;
711
712 err = xlbd_reserve_minors(minor, nr_minors);
713 if (err)
714 goto out;
715 err = -ENODEV;
716
717 gd = alloc_disk(nr_minors);
718 if (gd == NULL)
719 goto release;
720
721 strcpy(gd->disk_name, DEV_NAME);
722 ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset);
723 BUG_ON(ptr >= gd->disk_name + DISK_NAME_LEN);
724 if (nr_minors > 1)
725 *ptr = 0;
726 else
727 snprintf(ptr, gd->disk_name + DISK_NAME_LEN - ptr,
728 "%d", minor & (nr_parts - 1));
729
730 gd->major = XENVBD_MAJOR;
731 gd->first_minor = minor;
732 gd->fops = &xlvbd_block_fops;
733 gd->private_data = info;
734 gd->driverfs_dev = &(info->xbdev->dev);
735 set_capacity(gd, capacity);
736
737 if (xlvbd_init_blk_queue(gd, sector_size)) {
738 del_gendisk(gd);
739 goto release;
740 }
741
742 info->rq = gd->queue;
743 info->gd = gd;
744
745 xlvbd_flush(info);
746
747 if (vdisk_info & VDISK_READONLY)
748 set_disk_ro(gd, 1);
749
750 if (vdisk_info & VDISK_REMOVABLE)
751 gd->flags |= GENHD_FL_REMOVABLE;
752
753 if (vdisk_info & VDISK_CDROM)
754 gd->flags |= GENHD_FL_CD;
755
756 return 0;
757
758 release:
759 xlbd_release_minors(minor, nr_minors);
760 out:
761 return err;
762 }
763
764 static void xlvbd_release_gendisk(struct blkfront_info *info)
765 {
766 unsigned int minor, nr_minors;
767 unsigned long flags;
768
769 if (info->rq == NULL)
770 return;
771
772 spin_lock_irqsave(&info->io_lock, flags);
773
774 /* No more blkif_request(). */
775 blk_stop_queue(info->rq);
776
777 /* No more gnttab callback work. */
778 gnttab_cancel_free_callback(&info->callback);
779 spin_unlock_irqrestore(&info->io_lock, flags);
780
781 /* Flush gnttab callback work. Must be done with no locks held. */
782 flush_work(&info->work);
783
784 del_gendisk(info->gd);
785
786 minor = info->gd->first_minor;
787 nr_minors = info->gd->minors;
788 xlbd_release_minors(minor, nr_minors);
789
790 blk_cleanup_queue(info->rq);
791 info->rq = NULL;
792
793 put_disk(info->gd);
794 info->gd = NULL;
795 }
796
797 static void kick_pending_request_queues(struct blkfront_info *info)
798 {
799 if (!RING_FULL(&info->ring)) {
800 /* Re-enable calldowns. */
801 blk_start_queue(info->rq);
802 /* Kick things off immediately. */
803 do_blkif_request(info->rq);
804 }
805 }
806
807 static void blkif_restart_queue(struct work_struct *work)
808 {
809 struct blkfront_info *info = container_of(work, struct blkfront_info, work);
810
811 spin_lock_irq(&info->io_lock);
812 if (info->connected == BLKIF_STATE_CONNECTED)
813 kick_pending_request_queues(info);
814 spin_unlock_irq(&info->io_lock);
815 }
816
817 static void blkif_free(struct blkfront_info *info, int suspend)
818 {
819 struct grant *persistent_gnt;
820 struct grant *n;
821
822 /* Prevent new requests being issued until we fix things up. */
823 spin_lock_irq(&info->io_lock);
824 info->connected = suspend ?
825 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
826 /* No more blkif_request(). */
827 if (info->rq)
828 blk_stop_queue(info->rq);
829
830 /* Remove all persistent grants */
831 if (!list_empty(&info->persistent_gnts)) {
832 list_for_each_entry_safe(persistent_gnt, n,
833 &info->persistent_gnts, node) {
834 list_del(&persistent_gnt->node);
835 if (persistent_gnt->gref != GRANT_INVALID_REF) {
836 gnttab_end_foreign_access(persistent_gnt->gref,
837 0, 0UL);
838 info->persistent_gnts_c--;
839 }
840 __free_page(pfn_to_page(persistent_gnt->pfn));
841 kfree(persistent_gnt);
842 }
843 }
844 BUG_ON(info->persistent_gnts_c != 0);
845
846 /* No more gnttab callback work. */
847 gnttab_cancel_free_callback(&info->callback);
848 spin_unlock_irq(&info->io_lock);
849
850 /* Flush gnttab callback work. Must be done with no locks held. */
851 flush_work(&info->work);
852
853 /* Free resources associated with old device channel. */
854 if (info->ring_ref != GRANT_INVALID_REF) {
855 gnttab_end_foreign_access(info->ring_ref, 0,
856 (unsigned long)info->ring.sring);
857 info->ring_ref = GRANT_INVALID_REF;
858 info->ring.sring = NULL;
859 }
860 if (info->irq)
861 unbind_from_irqhandler(info->irq, info);
862 info->evtchn = info->irq = 0;
863
864 }
865
866 static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
867 struct blkif_response *bret)
868 {
869 int i = 0;
870 struct scatterlist *sg;
871 char *bvec_data;
872 void *shared_data;
873 int nseg;
874
875 nseg = s->req.u.rw.nr_segments;
876
877 if (bret->operation == BLKIF_OP_READ) {
878 /*
879 * Copy the data received from the backend into the bvec.
880 * Since bv_offset can be different than 0, and bv_len different
881 * than PAGE_SIZE, we have to keep track of the current offset,
882 * to be sure we are copying the data from the right shared page.
883 */
884 for_each_sg(s->sg, sg, nseg, i) {
885 BUG_ON(sg->offset + sg->length > PAGE_SIZE);
886 shared_data = kmap_atomic(
887 pfn_to_page(s->grants_used[i]->pfn));
888 bvec_data = kmap_atomic(sg_page(sg));
889 memcpy(bvec_data + sg->offset,
890 shared_data + sg->offset,
891 sg->length);
892 kunmap_atomic(bvec_data);
893 kunmap_atomic(shared_data);
894 }
895 }
896 /* Add the persistent grant into the list of free grants */
897 for (i = 0; i < s->req.u.rw.nr_segments; i++) {
898 list_add(&s->grants_used[i]->node, &info->persistent_gnts);
899 info->persistent_gnts_c++;
900 }
901 }
902
903 static irqreturn_t blkif_interrupt(int irq, void *dev_id)
904 {
905 struct request *req;
906 struct blkif_response *bret;
907 RING_IDX i, rp;
908 unsigned long flags;
909 struct blkfront_info *info = (struct blkfront_info *)dev_id;
910 int error;
911
912 spin_lock_irqsave(&info->io_lock, flags);
913
914 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
915 spin_unlock_irqrestore(&info->io_lock, flags);
916 return IRQ_HANDLED;
917 }
918
919 again:
920 rp = info->ring.sring->rsp_prod;
921 rmb(); /* Ensure we see queued responses up to 'rp'. */
922
923 for (i = info->ring.rsp_cons; i != rp; i++) {
924 unsigned long id;
925
926 bret = RING_GET_RESPONSE(&info->ring, i);
927 id = bret->id;
928 /*
929 * The backend has messed up and given us an id that we would
930 * never have given to it (we stamp it up to BLK_RING_SIZE -
931 * look in get_id_from_freelist.
932 */
933 if (id >= BLK_RING_SIZE) {
934 WARN(1, "%s: response to %s has incorrect id (%ld)\n",
935 info->gd->disk_name, op_name(bret->operation), id);
936 /* We can't safely get the 'struct request' as
937 * the id is busted. */
938 continue;
939 }
940 req = info->shadow[id].request;
941
942 if (bret->operation != BLKIF_OP_DISCARD)
943 blkif_completion(&info->shadow[id], info, bret);
944
945 if (add_id_to_freelist(info, id)) {
946 WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n",
947 info->gd->disk_name, op_name(bret->operation), id);
948 continue;
949 }
950
951 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
952 switch (bret->operation) {
953 case BLKIF_OP_DISCARD:
954 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
955 struct request_queue *rq = info->rq;
956 printk(KERN_WARNING "blkfront: %s: %s op failed\n",
957 info->gd->disk_name, op_name(bret->operation));
958 error = -EOPNOTSUPP;
959 info->feature_discard = 0;
960 info->feature_secdiscard = 0;
961 queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
962 queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq);
963 }
964 __blk_end_request_all(req, error);
965 break;
966 case BLKIF_OP_FLUSH_DISKCACHE:
967 case BLKIF_OP_WRITE_BARRIER:
968 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
969 printk(KERN_WARNING "blkfront: %s: %s op failed\n",
970 info->gd->disk_name, op_name(bret->operation));
971 error = -EOPNOTSUPP;
972 }
973 if (unlikely(bret->status == BLKIF_RSP_ERROR &&
974 info->shadow[id].req.u.rw.nr_segments == 0)) {
975 printk(KERN_WARNING "blkfront: %s: empty %s op failed\n",
976 info->gd->disk_name, op_name(bret->operation));
977 error = -EOPNOTSUPP;
978 }
979 if (unlikely(error)) {
980 if (error == -EOPNOTSUPP)
981 error = 0;
982 info->feature_flush = 0;
983 info->flush_op = 0;
984 xlvbd_flush(info);
985 }
986 /* fall through */
987 case BLKIF_OP_READ:
988 case BLKIF_OP_WRITE:
989 if (unlikely(bret->status != BLKIF_RSP_OKAY))
990 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
991 "request: %x\n", bret->status);
992
993 __blk_end_request_all(req, error);
994 break;
995 default:
996 BUG();
997 }
998 }
999
1000 info->ring.rsp_cons = i;
1001
1002 if (i != info->ring.req_prod_pvt) {
1003 int more_to_do;
1004 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
1005 if (more_to_do)
1006 goto again;
1007 } else
1008 info->ring.sring->rsp_event = i + 1;
1009
1010 kick_pending_request_queues(info);
1011
1012 spin_unlock_irqrestore(&info->io_lock, flags);
1013
1014 return IRQ_HANDLED;
1015 }
1016
1017
1018 static int setup_blkring(struct xenbus_device *dev,
1019 struct blkfront_info *info)
1020 {
1021 struct blkif_sring *sring;
1022 int err, i;
1023
1024 info->ring_ref = GRANT_INVALID_REF;
1025
1026 sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
1027 if (!sring) {
1028 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
1029 return -ENOMEM;
1030 }
1031 SHARED_RING_INIT(sring);
1032 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
1033
1034 for (i = 0; i < BLK_RING_SIZE; i++)
1035 sg_init_table(info->shadow[i].sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
1036
1037 /* Allocate memory for grants */
1038 err = fill_grant_buffer(info, BLK_RING_SIZE *
1039 BLKIF_MAX_SEGMENTS_PER_REQUEST);
1040 if (err)
1041 goto fail;
1042
1043 err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
1044 if (err < 0) {
1045 free_page((unsigned long)sring);
1046 info->ring.sring = NULL;
1047 goto fail;
1048 }
1049 info->ring_ref = err;
1050
1051 err = xenbus_alloc_evtchn(dev, &info->evtchn);
1052 if (err)
1053 goto fail;
1054
1055 err = bind_evtchn_to_irqhandler(info->evtchn, blkif_interrupt, 0,
1056 "blkif", info);
1057 if (err <= 0) {
1058 xenbus_dev_fatal(dev, err,
1059 "bind_evtchn_to_irqhandler failed");
1060 goto fail;
1061 }
1062 info->irq = err;
1063
1064 return 0;
1065 fail:
1066 blkif_free(info, 0);
1067 return err;
1068 }
1069
1070
1071 /* Common code used when first setting up, and when resuming. */
1072 static int talk_to_blkback(struct xenbus_device *dev,
1073 struct blkfront_info *info)
1074 {
1075 const char *message = NULL;
1076 struct xenbus_transaction xbt;
1077 int err;
1078
1079 /* Create shared ring, alloc event channel. */
1080 err = setup_blkring(dev, info);
1081 if (err)
1082 goto out;
1083
1084 again:
1085 err = xenbus_transaction_start(&xbt);
1086 if (err) {
1087 xenbus_dev_fatal(dev, err, "starting transaction");
1088 goto destroy_blkring;
1089 }
1090
1091 err = xenbus_printf(xbt, dev->nodename,
1092 "ring-ref", "%u", info->ring_ref);
1093 if (err) {
1094 message = "writing ring-ref";
1095 goto abort_transaction;
1096 }
1097 err = xenbus_printf(xbt, dev->nodename,
1098 "event-channel", "%u", info->evtchn);
1099 if (err) {
1100 message = "writing event-channel";
1101 goto abort_transaction;
1102 }
1103 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
1104 XEN_IO_PROTO_ABI_NATIVE);
1105 if (err) {
1106 message = "writing protocol";
1107 goto abort_transaction;
1108 }
1109 err = xenbus_printf(xbt, dev->nodename,
1110 "feature-persistent", "%u", 1);
1111 if (err)
1112 dev_warn(&dev->dev,
1113 "writing persistent grants feature to xenbus");
1114
1115 err = xenbus_transaction_end(xbt, 0);
1116 if (err) {
1117 if (err == -EAGAIN)
1118 goto again;
1119 xenbus_dev_fatal(dev, err, "completing transaction");
1120 goto destroy_blkring;
1121 }
1122
1123 xenbus_switch_state(dev, XenbusStateInitialised);
1124
1125 return 0;
1126
1127 abort_transaction:
1128 xenbus_transaction_end(xbt, 1);
1129 if (message)
1130 xenbus_dev_fatal(dev, err, "%s", message);
1131 destroy_blkring:
1132 blkif_free(info, 0);
1133 out:
1134 return err;
1135 }
1136
1137 /**
1138 * Entry point to this code when a new device is created. Allocate the basic
1139 * structures and the ring buffer for communication with the backend, and
1140 * inform the backend of the appropriate details for those. Switch to
1141 * Initialised state.
1142 */
1143 static int blkfront_probe(struct xenbus_device *dev,
1144 const struct xenbus_device_id *id)
1145 {
1146 int err, vdevice, i;
1147 struct blkfront_info *info;
1148
1149 /* FIXME: Use dynamic device id if this is not set. */
1150 err = xenbus_scanf(XBT_NIL, dev->nodename,
1151 "virtual-device", "%i", &vdevice);
1152 if (err != 1) {
1153 /* go looking in the extended area instead */
1154 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext",
1155 "%i", &vdevice);
1156 if (err != 1) {
1157 xenbus_dev_fatal(dev, err, "reading virtual-device");
1158 return err;
1159 }
1160 }
1161
1162 if (xen_hvm_domain()) {
1163 char *type;
1164 int len;
1165 /* no unplug has been done: do not hook devices != xen vbds */
1166 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) {
1167 int major;
1168
1169 if (!VDEV_IS_EXTENDED(vdevice))
1170 major = BLKIF_MAJOR(vdevice);
1171 else
1172 major = XENVBD_MAJOR;
1173
1174 if (major != XENVBD_MAJOR) {
1175 printk(KERN_INFO
1176 "%s: HVM does not support vbd %d as xen block device\n",
1177 __FUNCTION__, vdevice);
1178 return -ENODEV;
1179 }
1180 }
1181 /* do not create a PV cdrom device if we are an HVM guest */
1182 type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
1183 if (IS_ERR(type))
1184 return -ENODEV;
1185 if (strncmp(type, "cdrom", 5) == 0) {
1186 kfree(type);
1187 return -ENODEV;
1188 }
1189 kfree(type);
1190 }
1191 info = kzalloc(sizeof(*info), GFP_KERNEL);
1192 if (!info) {
1193 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
1194 return -ENOMEM;
1195 }
1196
1197 mutex_init(&info->mutex);
1198 spin_lock_init(&info->io_lock);
1199 info->xbdev = dev;
1200 info->vdevice = vdevice;
1201 INIT_LIST_HEAD(&info->persistent_gnts);
1202 info->persistent_gnts_c = 0;
1203 info->connected = BLKIF_STATE_DISCONNECTED;
1204 INIT_WORK(&info->work, blkif_restart_queue);
1205
1206 for (i = 0; i < BLK_RING_SIZE; i++)
1207 info->shadow[i].req.u.rw.id = i+1;
1208 info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
1209
1210 /* Front end dir is a number, which is used as the id. */
1211 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
1212 dev_set_drvdata(&dev->dev, info);
1213
1214 err = talk_to_blkback(dev, info);
1215 if (err) {
1216 kfree(info);
1217 dev_set_drvdata(&dev->dev, NULL);
1218 return err;
1219 }
1220
1221 return 0;
1222 }
1223
1224
1225 static int blkif_recover(struct blkfront_info *info)
1226 {
1227 int i;
1228 struct blkif_request *req;
1229 struct blk_shadow *copy;
1230 int j;
1231
1232 /* Stage 1: Make a safe copy of the shadow state. */
1233 copy = kmemdup(info->shadow, sizeof(info->shadow),
1234 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
1235 if (!copy)
1236 return -ENOMEM;
1237
1238 /* Stage 2: Set up free list. */
1239 memset(&info->shadow, 0, sizeof(info->shadow));
1240 for (i = 0; i < BLK_RING_SIZE; i++)
1241 info->shadow[i].req.u.rw.id = i+1;
1242 info->shadow_free = info->ring.req_prod_pvt;
1243 info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
1244
1245 /* Stage 3: Find pending requests and requeue them. */
1246 for (i = 0; i < BLK_RING_SIZE; i++) {
1247 /* Not in use? */
1248 if (!copy[i].request)
1249 continue;
1250
1251 /* Grab a request slot and copy shadow state into it. */
1252 req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
1253 *req = copy[i].req;
1254
1255 /* We get a new request id, and must reset the shadow state. */
1256 req->u.rw.id = get_id_from_freelist(info);
1257 memcpy(&info->shadow[req->u.rw.id], &copy[i], sizeof(copy[i]));
1258
1259 if (req->operation != BLKIF_OP_DISCARD) {
1260 /* Rewrite any grant references invalidated by susp/resume. */
1261 for (j = 0; j < req->u.rw.nr_segments; j++)
1262 gnttab_grant_foreign_access_ref(
1263 req->u.rw.seg[j].gref,
1264 info->xbdev->otherend_id,
1265 pfn_to_mfn(copy[i].grants_used[j]->pfn),
1266 0);
1267 }
1268 info->shadow[req->u.rw.id].req = *req;
1269
1270 info->ring.req_prod_pvt++;
1271 }
1272
1273 kfree(copy);
1274
1275 xenbus_switch_state(info->xbdev, XenbusStateConnected);
1276
1277 spin_lock_irq(&info->io_lock);
1278
1279 /* Now safe for us to use the shared ring */
1280 info->connected = BLKIF_STATE_CONNECTED;
1281
1282 /* Send off requeued requests */
1283 flush_requests(info);
1284
1285 /* Kick any other new requests queued since we resumed */
1286 kick_pending_request_queues(info);
1287
1288 spin_unlock_irq(&info->io_lock);
1289
1290 return 0;
1291 }
1292
1293 /**
1294 * We are reconnecting to the backend, due to a suspend/resume, or a backend
1295 * driver restart. We tear down our blkif structure and recreate it, but
1296 * leave the device-layer structures intact so that this is transparent to the
1297 * rest of the kernel.
1298 */
1299 static int blkfront_resume(struct xenbus_device *dev)
1300 {
1301 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1302 int err;
1303
1304 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
1305
1306 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
1307
1308 err = talk_to_blkback(dev, info);
1309 if (info->connected == BLKIF_STATE_SUSPENDED && !err)
1310 err = blkif_recover(info);
1311
1312 return err;
1313 }
1314
1315 static void
1316 blkfront_closing(struct blkfront_info *info)
1317 {
1318 struct xenbus_device *xbdev = info->xbdev;
1319 struct block_device *bdev = NULL;
1320
1321 mutex_lock(&info->mutex);
1322
1323 if (xbdev->state == XenbusStateClosing) {
1324 mutex_unlock(&info->mutex);
1325 return;
1326 }
1327
1328 if (info->gd)
1329 bdev = bdget_disk(info->gd, 0);
1330
1331 mutex_unlock(&info->mutex);
1332
1333 if (!bdev) {
1334 xenbus_frontend_closed(xbdev);
1335 return;
1336 }
1337
1338 mutex_lock(&bdev->bd_mutex);
1339
1340 if (bdev->bd_openers) {
1341 xenbus_dev_error(xbdev, -EBUSY,
1342 "Device in use; refusing to close");
1343 xenbus_switch_state(xbdev, XenbusStateClosing);
1344 } else {
1345 xlvbd_release_gendisk(info);
1346 xenbus_frontend_closed(xbdev);
1347 }
1348
1349 mutex_unlock(&bdev->bd_mutex);
1350 bdput(bdev);
1351 }
1352
1353 static void blkfront_setup_discard(struct blkfront_info *info)
1354 {
1355 int err;
1356 char *type;
1357 unsigned int discard_granularity;
1358 unsigned int discard_alignment;
1359 unsigned int discard_secure;
1360
1361 type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL);
1362 if (IS_ERR(type))
1363 return;
1364
1365 info->feature_secdiscard = 0;
1366 if (strncmp(type, "phy", 3) == 0) {
1367 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1368 "discard-granularity", "%u", &discard_granularity,
1369 "discard-alignment", "%u", &discard_alignment,
1370 NULL);
1371 if (!err) {
1372 info->feature_discard = 1;
1373 info->discard_granularity = discard_granularity;
1374 info->discard_alignment = discard_alignment;
1375 }
1376 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1377 "discard-secure", "%d", &discard_secure,
1378 NULL);
1379 if (!err)
1380 info->feature_secdiscard = discard_secure;
1381
1382 } else if (strncmp(type, "file", 4) == 0)
1383 info->feature_discard = 1;
1384
1385 kfree(type);
1386 }
1387
1388 /*
1389 * Invoked when the backend is finally 'ready' (and has told produced
1390 * the details about the physical device - #sectors, size, etc).
1391 */
1392 static void blkfront_connect(struct blkfront_info *info)
1393 {
1394 unsigned long long sectors;
1395 unsigned long sector_size;
1396 unsigned int binfo;
1397 int err;
1398 int barrier, flush, discard, persistent;
1399
1400 switch (info->connected) {
1401 case BLKIF_STATE_CONNECTED:
1402 /*
1403 * Potentially, the back-end may be signalling
1404 * a capacity change; update the capacity.
1405 */
1406 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1407 "sectors", "%Lu", &sectors);
1408 if (XENBUS_EXIST_ERR(err))
1409 return;
1410 printk(KERN_INFO "Setting capacity to %Lu\n",
1411 sectors);
1412 set_capacity(info->gd, sectors);
1413 revalidate_disk(info->gd);
1414
1415 /* fall through */
1416 case BLKIF_STATE_SUSPENDED:
1417 return;
1418
1419 default:
1420 break;
1421 }
1422
1423 dev_dbg(&info->xbdev->dev, "%s:%s.\n",
1424 __func__, info->xbdev->otherend);
1425
1426 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1427 "sectors", "%llu", &sectors,
1428 "info", "%u", &binfo,
1429 "sector-size", "%lu", &sector_size,
1430 NULL);
1431 if (err) {
1432 xenbus_dev_fatal(info->xbdev, err,
1433 "reading backend fields at %s",
1434 info->xbdev->otherend);
1435 return;
1436 }
1437
1438 info->feature_flush = 0;
1439 info->flush_op = 0;
1440
1441 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1442 "feature-barrier", "%d", &barrier,
1443 NULL);
1444
1445 /*
1446 * If there's no "feature-barrier" defined, then it means
1447 * we're dealing with a very old backend which writes
1448 * synchronously; nothing to do.
1449 *
1450 * If there are barriers, then we use flush.
1451 */
1452 if (!err && barrier) {
1453 info->feature_flush = REQ_FLUSH | REQ_FUA;
1454 info->flush_op = BLKIF_OP_WRITE_BARRIER;
1455 }
1456 /*
1457 * And if there is "feature-flush-cache" use that above
1458 * barriers.
1459 */
1460 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1461 "feature-flush-cache", "%d", &flush,
1462 NULL);
1463
1464 if (!err && flush) {
1465 info->feature_flush = REQ_FLUSH;
1466 info->flush_op = BLKIF_OP_FLUSH_DISKCACHE;
1467 }
1468
1469 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1470 "feature-discard", "%d", &discard,
1471 NULL);
1472
1473 if (!err && discard)
1474 blkfront_setup_discard(info);
1475
1476 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1477 "feature-persistent", "%u", &persistent,
1478 NULL);
1479 if (err)
1480 info->feature_persistent = 0;
1481 else
1482 info->feature_persistent = persistent;
1483
1484 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
1485 if (err) {
1486 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
1487 info->xbdev->otherend);
1488 return;
1489 }
1490
1491 xenbus_switch_state(info->xbdev, XenbusStateConnected);
1492
1493 /* Kick pending requests. */
1494 spin_lock_irq(&info->io_lock);
1495 info->connected = BLKIF_STATE_CONNECTED;
1496 kick_pending_request_queues(info);
1497 spin_unlock_irq(&info->io_lock);
1498
1499 add_disk(info->gd);
1500
1501 info->is_ready = 1;
1502 }
1503
1504 /**
1505 * Callback received when the backend's state changes.
1506 */
1507 static void blkback_changed(struct xenbus_device *dev,
1508 enum xenbus_state backend_state)
1509 {
1510 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1511
1512 dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state);
1513
1514 switch (backend_state) {
1515 case XenbusStateInitialising:
1516 case XenbusStateInitWait:
1517 case XenbusStateInitialised:
1518 case XenbusStateReconfiguring:
1519 case XenbusStateReconfigured:
1520 case XenbusStateUnknown:
1521 break;
1522
1523 case XenbusStateConnected:
1524 blkfront_connect(info);
1525 break;
1526
1527 case XenbusStateClosed:
1528 if (dev->state == XenbusStateClosed)
1529 break;
1530 /* Missed the backend's Closing state -- fallthrough */
1531 case XenbusStateClosing:
1532 blkfront_closing(info);
1533 break;
1534 }
1535 }
1536
1537 static int blkfront_remove(struct xenbus_device *xbdev)
1538 {
1539 struct blkfront_info *info = dev_get_drvdata(&xbdev->dev);
1540 struct block_device *bdev = NULL;
1541 struct gendisk *disk;
1542
1543 dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
1544
1545 blkif_free(info, 0);
1546
1547 mutex_lock(&info->mutex);
1548
1549 disk = info->gd;
1550 if (disk)
1551 bdev = bdget_disk(disk, 0);
1552
1553 info->xbdev = NULL;
1554 mutex_unlock(&info->mutex);
1555
1556 if (!bdev) {
1557 kfree(info);
1558 return 0;
1559 }
1560
1561 /*
1562 * The xbdev was removed before we reached the Closed
1563 * state. See if it's safe to remove the disk. If the bdev
1564 * isn't closed yet, we let release take care of it.
1565 */
1566
1567 mutex_lock(&bdev->bd_mutex);
1568 info = disk->private_data;
1569
1570 dev_warn(disk_to_dev(disk),
1571 "%s was hot-unplugged, %d stale handles\n",
1572 xbdev->nodename, bdev->bd_openers);
1573
1574 if (info && !bdev->bd_openers) {
1575 xlvbd_release_gendisk(info);
1576 disk->private_data = NULL;
1577 kfree(info);
1578 }
1579
1580 mutex_unlock(&bdev->bd_mutex);
1581 bdput(bdev);
1582
1583 return 0;
1584 }
1585
1586 static int blkfront_is_ready(struct xenbus_device *dev)
1587 {
1588 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
1589
1590 return info->is_ready && info->xbdev;
1591 }
1592
1593 static int blkif_open(struct block_device *bdev, fmode_t mode)
1594 {
1595 struct gendisk *disk = bdev->bd_disk;
1596 struct blkfront_info *info;
1597 int err = 0;
1598
1599 mutex_lock(&blkfront_mutex);
1600
1601 info = disk->private_data;
1602 if (!info) {
1603 /* xbdev gone */
1604 err = -ERESTARTSYS;
1605 goto out;
1606 }
1607
1608 mutex_lock(&info->mutex);
1609
1610 if (!info->gd)
1611 /* xbdev is closed */
1612 err = -ERESTARTSYS;
1613
1614 mutex_unlock(&info->mutex);
1615
1616 out:
1617 mutex_unlock(&blkfront_mutex);
1618 return err;
1619 }
1620
1621 static void blkif_release(struct gendisk *disk, fmode_t mode)
1622 {
1623 struct blkfront_info *info = disk->private_data;
1624 struct block_device *bdev;
1625 struct xenbus_device *xbdev;
1626
1627 mutex_lock(&blkfront_mutex);
1628
1629 bdev = bdget_disk(disk, 0);
1630
1631 if (bdev->bd_openers)
1632 goto out;
1633
1634 /*
1635 * Check if we have been instructed to close. We will have
1636 * deferred this request, because the bdev was still open.
1637 */
1638
1639 mutex_lock(&info->mutex);
1640 xbdev = info->xbdev;
1641
1642 if (xbdev && xbdev->state == XenbusStateClosing) {
1643 /* pending switch to state closed */
1644 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
1645 xlvbd_release_gendisk(info);
1646 xenbus_frontend_closed(info->xbdev);
1647 }
1648
1649 mutex_unlock(&info->mutex);
1650
1651 if (!xbdev) {
1652 /* sudden device removal */
1653 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
1654 xlvbd_release_gendisk(info);
1655 disk->private_data = NULL;
1656 kfree(info);
1657 }
1658
1659 out:
1660 bdput(bdev);
1661 mutex_unlock(&blkfront_mutex);
1662 }
1663
1664 static const struct block_device_operations xlvbd_block_fops =
1665 {
1666 .owner = THIS_MODULE,
1667 .open = blkif_open,
1668 .release = blkif_release,
1669 .getgeo = blkif_getgeo,
1670 .ioctl = blkif_ioctl,
1671 };
1672
1673
1674 static const struct xenbus_device_id blkfront_ids[] = {
1675 { "vbd" },
1676 { "" }
1677 };
1678
1679 static DEFINE_XENBUS_DRIVER(blkfront, ,
1680 .probe = blkfront_probe,
1681 .remove = blkfront_remove,
1682 .resume = blkfront_resume,
1683 .otherend_changed = blkback_changed,
1684 .is_ready = blkfront_is_ready,
1685 );
1686
1687 static int __init xlblk_init(void)
1688 {
1689 int ret;
1690
1691 if (!xen_domain())
1692 return -ENODEV;
1693
1694 if (xen_hvm_domain() && !xen_platform_pci_unplug)
1695 return -ENODEV;
1696
1697 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
1698 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
1699 XENVBD_MAJOR, DEV_NAME);
1700 return -ENODEV;
1701 }
1702
1703 ret = xenbus_register_frontend(&blkfront_driver);
1704 if (ret) {
1705 unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
1706 return ret;
1707 }
1708
1709 return 0;
1710 }
1711 module_init(xlblk_init);
1712
1713
1714 static void __exit xlblk_exit(void)
1715 {
1716 xenbus_unregister_driver(&blkfront_driver);
1717 unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
1718 kfree(minors);
1719 }
1720 module_exit(xlblk_exit);
1721
1722 MODULE_DESCRIPTION("Xen virtual block device frontend");
1723 MODULE_LICENSE("GPL");
1724 MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
1725 MODULE_ALIAS("xen:vbd");
1726 MODULE_ALIAS("xenblk");
kernel source for telekom puls (alcatel/mediatek)