blob: c4a4c900628891c31fec541277cb7ffea9a3e68b [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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090043#include <linux/slab.h>
Arnd Bergmann2a48fc02010-06-02 14:28:52 +020044#include <linux/mutex.h>
Jens Axboe9e973e62009-02-24 08:10:09 +010045#include <linux/scatterlist.h>
Akinobu Mita34ae2e42012-01-21 00:15:26 +090046#include <linux/bitmap.h>
Roger Pau Monne155b7ed2013-03-18 17:49:34 +010047#include <linux/list.h>
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070048
Jeremy Fitzhardinge1ccbf532009-10-06 15:11:14 -070049#include <xen/xen.h>
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070050#include <xen/xenbus.h>
51#include <xen/grant_table.h>
52#include <xen/events.h>
53#include <xen/page.h>
Stefano Stabellinic1c54132010-05-14 12:44:30 +010054#include <xen/platform_pci.h>
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070055
56#include <xen/interface/grant_table.h>
57#include <xen/interface/io/blkif.h>
Markus Armbruster3e334232008-04-02 10:54:02 -070058#include <xen/interface/io/protocols.h>
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070059
60#include <asm/xen/hypervisor.h>
61
62enum blkif_state {
63 BLKIF_STATE_DISCONNECTED,
64 BLKIF_STATE_CONNECTED,
65 BLKIF_STATE_SUSPENDED,
66};
67
Roger Pau Monne0a8704a2012-10-24 18:58:45 +020068struct grant {
69 grant_ref_t gref;
70 unsigned long pfn;
Roger Pau Monne155b7ed2013-03-18 17:49:34 +010071 struct list_head node;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +020072};
73
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070074struct blk_shadow {
75 struct blkif_request req;
Jeremy Fitzhardingea945b982010-11-01 17:03:14 -040076 struct request *request;
Roger Pau Monne402b27f2013-04-18 16:06:54 +020077 struct grant **grants_used;
78 struct grant **indirect_grants;
Roger Pau Monneb7649152013-05-02 10:58:50 +020079 struct scatterlist *sg;
Roger Pau Monne402b27f2013-04-18 16:06:54 +020080};
81
82struct split_bio {
83 struct bio *bio;
84 atomic_t pending;
85 int err;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070086};
87
Arnd Bergmann2a48fc02010-06-02 14:28:52 +020088static DEFINE_MUTEX(blkfront_mutex);
Alexey Dobriyan83d5cde2009-09-21 17:01:13 -070089static const struct block_device_operations xlvbd_block_fops;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070090
Roger Pau Monne402b27f2013-04-18 16:06:54 +020091/*
92 * Maximum number of segments in indirect requests, the actual value used by
93 * the frontend driver is the minimum of this value and the value provided
94 * by the backend driver.
95 */
96
97static unsigned int xen_blkif_max_segments = 32;
Konrad Rzeszutek Wilk2d5dc3b2013-05-15 10:39:34 -040098module_param_named(max, xen_blkif_max_segments, int, S_IRUGO);
99MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests (default is 32)");
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200100
Jeremy Fitzhardinge667c78af2010-12-08 12:39:12 -0800101#define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700102
103/*
104 * We have one of these per vbd, whether ide, scsi or 'other'. They
105 * hang in private_data off the gendisk structure. We may end up
106 * putting all kinds of interesting stuff here :-)
107 */
108struct blkfront_info
109{
Steven Noonan34678112012-02-17 12:04:44 -0800110 spinlock_t io_lock;
Daniel Stoddenb70f5fa2010-04-30 22:01:19 +0000111 struct mutex mutex;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700112 struct xenbus_device *xbdev;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700113 struct gendisk *gd;
114 int vdevice;
115 blkif_vdev_t handle;
116 enum blkif_state connected;
117 int ring_ref;
118 struct blkif_front_ring ring;
119 unsigned int evtchn, irq;
120 struct request_queue *rq;
121 struct work_struct work;
122 struct gnttab_free_callback callback;
123 struct blk_shadow shadow[BLK_RING_SIZE];
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100124 struct list_head grants;
125 struct list_head indirect_pages;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200126 unsigned int persistent_gnts_c;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700127 unsigned long shadow_free;
Tejun Heo4913efe2010-09-03 11:56:16 +0200128 unsigned int feature_flush;
Konrad Rzeszutek Wilkedf6ef52011-05-03 12:01:11 -0400129 unsigned int flush_op;
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -0400130 unsigned int feature_discard:1;
131 unsigned int feature_secdiscard:1;
Li Dongyanged30bf32011-09-01 18:39:09 +0800132 unsigned int discard_granularity;
133 unsigned int discard_alignment;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200134 unsigned int feature_persistent:1;
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200135 unsigned int max_indirect_segments;
Christian Limpach1d78d702008-04-02 10:54:04 -0700136 int is_ready;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700137};
138
Jan Beulich0e345822010-08-07 18:28:55 +0200139static unsigned int nr_minors;
140static unsigned long *minors;
141static DEFINE_SPINLOCK(minor_lock);
142
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700143#define MAXIMUM_OUTSTANDING_BLOCK_REQS \
144 (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
145#define GRANT_INVALID_REF 0
146
147#define PARTS_PER_DISK 16
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700148#define PARTS_PER_EXT_DISK 256
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700149
150#define BLKIF_MAJOR(dev) ((dev)>>8)
151#define BLKIF_MINOR(dev) ((dev) & 0xff)
152
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700153#define EXT_SHIFT 28
154#define EXTENDED (1<<EXT_SHIFT)
155#define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
156#define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
Stefano Stabellinic80a4202010-12-02 17:55:00 +0000157#define EMULATED_HD_DISK_MINOR_OFFSET (0)
158#define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256)
Stefan Bader196cfe22011-07-14 15:30:22 +0200159#define EMULATED_SD_DISK_MINOR_OFFSET (0)
160#define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700161
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700162#define DEV_NAME "xvd" /* name in /dev */
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700163
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200164#define SEGS_PER_INDIRECT_FRAME \
165 (PAGE_SIZE/sizeof(struct blkif_request_segment_aligned))
166#define INDIRECT_GREFS(_segs) \
167 ((_segs + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
168
169static int blkfront_setup_indirect(struct blkfront_info *info);
170
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700171static int get_id_from_freelist(struct blkfront_info *info)
172{
173 unsigned long free = info->shadow_free;
Roel Kluinb9ed7252009-05-22 09:25:32 +0200174 BUG_ON(free >= BLK_RING_SIZE);
Konrad Rzeszutek Wilk97e36832011-10-12 12:12:36 -0400175 info->shadow_free = info->shadow[free].req.u.rw.id;
176 info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700177 return free;
178}
179
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -0400180static int add_id_to_freelist(struct blkfront_info *info,
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700181 unsigned long id)
182{
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -0400183 if (info->shadow[id].req.u.rw.id != id)
184 return -EINVAL;
185 if (info->shadow[id].request == NULL)
186 return -EINVAL;
Konrad Rzeszutek Wilk97e36832011-10-12 12:12:36 -0400187 info->shadow[id].req.u.rw.id = info->shadow_free;
Jeremy Fitzhardingea945b982010-11-01 17:03:14 -0400188 info->shadow[id].request = NULL;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700189 info->shadow_free = id;
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -0400190 return 0;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700191}
192
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100193static int fill_grant_buffer(struct blkfront_info *info, int num)
194{
195 struct page *granted_page;
196 struct grant *gnt_list_entry, *n;
197 int i = 0;
198
199 while(i < num) {
200 gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO);
201 if (!gnt_list_entry)
202 goto out_of_memory;
203
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100204 if (info->feature_persistent) {
205 granted_page = alloc_page(GFP_NOIO);
206 if (!granted_page) {
207 kfree(gnt_list_entry);
208 goto out_of_memory;
209 }
210 gnt_list_entry->pfn = page_to_pfn(granted_page);
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100211 }
212
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100213 gnt_list_entry->gref = GRANT_INVALID_REF;
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100214 list_add(&gnt_list_entry->node, &info->grants);
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100215 i++;
216 }
217
218 return 0;
219
220out_of_memory:
221 list_for_each_entry_safe(gnt_list_entry, n,
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100222 &info->grants, node) {
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100223 list_del(&gnt_list_entry->node);
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100224 if (info->feature_persistent)
225 __free_page(pfn_to_page(gnt_list_entry->pfn));
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100226 kfree(gnt_list_entry);
227 i--;
228 }
229 BUG_ON(i != 0);
230 return -ENOMEM;
231}
232
233static struct grant *get_grant(grant_ref_t *gref_head,
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100234 unsigned long pfn,
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100235 struct blkfront_info *info)
236{
237 struct grant *gnt_list_entry;
238 unsigned long buffer_mfn;
239
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100240 BUG_ON(list_empty(&info->grants));
241 gnt_list_entry = list_first_entry(&info->grants, struct grant,
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100242 node);
243 list_del(&gnt_list_entry->node);
244
245 if (gnt_list_entry->gref != GRANT_INVALID_REF) {
246 info->persistent_gnts_c--;
247 return gnt_list_entry;
248 }
249
250 /* Assign a gref to this page */
251 gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
252 BUG_ON(gnt_list_entry->gref == -ENOSPC);
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100253 if (!info->feature_persistent) {
254 BUG_ON(!pfn);
255 gnt_list_entry->pfn = pfn;
256 }
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100257 buffer_mfn = pfn_to_mfn(gnt_list_entry->pfn);
258 gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
259 info->xbdev->otherend_id,
260 buffer_mfn, 0);
261 return gnt_list_entry;
262}
263
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -0400264static const char *op_name(int op)
265{
266 static const char *const names[] = {
267 [BLKIF_OP_READ] = "read",
268 [BLKIF_OP_WRITE] = "write",
269 [BLKIF_OP_WRITE_BARRIER] = "barrier",
270 [BLKIF_OP_FLUSH_DISKCACHE] = "flush",
271 [BLKIF_OP_DISCARD] = "discard" };
272
273 if (op < 0 || op >= ARRAY_SIZE(names))
274 return "unknown";
275
276 if (!names[op])
277 return "reserved";
278
279 return names[op];
280}
Jan Beulich0e345822010-08-07 18:28:55 +0200281static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
282{
283 unsigned int end = minor + nr;
284 int rc;
285
286 if (end > nr_minors) {
287 unsigned long *bitmap, *old;
288
Thomas Meyerf0941482011-11-29 22:08:00 +0100289 bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap),
Jan Beulich0e345822010-08-07 18:28:55 +0200290 GFP_KERNEL);
291 if (bitmap == NULL)
292 return -ENOMEM;
293
294 spin_lock(&minor_lock);
295 if (end > nr_minors) {
296 old = minors;
297 memcpy(bitmap, minors,
298 BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
299 minors = bitmap;
300 nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
301 } else
302 old = bitmap;
303 spin_unlock(&minor_lock);
304 kfree(old);
305 }
306
307 spin_lock(&minor_lock);
308 if (find_next_bit(minors, end, minor) >= end) {
Akinobu Mita34ae2e42012-01-21 00:15:26 +0900309 bitmap_set(minors, minor, nr);
Jan Beulich0e345822010-08-07 18:28:55 +0200310 rc = 0;
311 } else
312 rc = -EBUSY;
313 spin_unlock(&minor_lock);
314
315 return rc;
316}
317
318static void xlbd_release_minors(unsigned int minor, unsigned int nr)
319{
320 unsigned int end = minor + nr;
321
322 BUG_ON(end > nr_minors);
323 spin_lock(&minor_lock);
Akinobu Mita34ae2e42012-01-21 00:15:26 +0900324 bitmap_clear(minors, minor, nr);
Jan Beulich0e345822010-08-07 18:28:55 +0200325 spin_unlock(&minor_lock);
326}
327
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700328static void blkif_restart_queue_callback(void *arg)
329{
330 struct blkfront_info *info = (struct blkfront_info *)arg;
331 schedule_work(&info->work);
332}
333
Harvey Harrisonafe42d72008-04-29 00:59:47 -0700334static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
Ian Campbell597592d2008-02-21 13:03:45 -0800335{
336 /* We don't have real geometry info, but let's at least return
337 values consistent with the size of the device */
338 sector_t nsect = get_capacity(bd->bd_disk);
339 sector_t cylinders = nsect;
340
341 hg->heads = 0xff;
342 hg->sectors = 0x3f;
343 sector_div(cylinders, hg->heads * hg->sectors);
344 hg->cylinders = cylinders;
345 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
346 hg->cylinders = 0xffff;
347 return 0;
348}
349
Al Viroa63c8482008-03-02 10:23:47 -0500350static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
Adrian Bunk62aa0052008-08-04 11:59:05 +0200351 unsigned command, unsigned long argument)
Christian Limpach440a01a2008-06-17 10:47:08 +0200352{
Al Viroa63c8482008-03-02 10:23:47 -0500353 struct blkfront_info *info = bdev->bd_disk->private_data;
Christian Limpach440a01a2008-06-17 10:47:08 +0200354 int i;
355
356 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
357 command, (long)argument);
358
359 switch (command) {
360 case CDROMMULTISESSION:
361 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
362 for (i = 0; i < sizeof(struct cdrom_multisession); i++)
363 if (put_user(0, (char __user *)(argument + i)))
364 return -EFAULT;
365 return 0;
366
367 case CDROM_GET_CAPABILITY: {
368 struct gendisk *gd = info->gd;
369 if (gd->flags & GENHD_FL_CD)
370 return 0;
371 return -EINVAL;
372 }
373
374 default:
375 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
376 command);*/
377 return -EINVAL; /* same return as native Linux */
378 }
379
380 return 0;
381}
382
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700383/*
Jeremy Fitzhardingec64e38e2010-11-01 14:32:27 -0400384 * Generate a Xen blkfront IO request from a blk layer request. Reads
Konrad Rzeszutek Wilkedf6ef52011-05-03 12:01:11 -0400385 * and writes are handled as expected.
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700386 *
Jeremy Fitzhardingec64e38e2010-11-01 14:32:27 -0400387 * @req: a request struct
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700388 */
389static int blkif_queue_request(struct request *req)
390{
391 struct blkfront_info *info = req->rq_disk->private_data;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700392 struct blkif_request *ring_req;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700393 unsigned long id;
394 unsigned int fsect, lsect;
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200395 int i, ref, n;
396 struct blkif_request_segment_aligned *segments = NULL;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200397
398 /*
399 * Used to store if we are able to queue the request by just using
400 * existing persistent grants, or if we have to get new grants,
401 * as there are not sufficiently many free.
402 */
403 bool new_persistent_gnts;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700404 grant_ref_t gref_head;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200405 struct grant *gnt_list_entry = NULL;
Jens Axboe9e973e62009-02-24 08:10:09 +0100406 struct scatterlist *sg;
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200407 int nseg, max_grefs;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700408
409 if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
410 return 1;
411
Roger Pau Monnec47206e2013-08-12 12:53:43 +0200412 max_grefs = req->nr_phys_segments;
413 if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST)
414 /*
415 * If we are using indirect segments we need to account
416 * for the indirect grefs used in the request.
417 */
418 max_grefs += INDIRECT_GREFS(req->nr_phys_segments);
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200419
420 /* Check if we have enough grants to allocate a requests */
421 if (info->persistent_gnts_c < max_grefs) {
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200422 new_persistent_gnts = 1;
423 if (gnttab_alloc_grant_references(
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200424 max_grefs - info->persistent_gnts_c,
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200425 &gref_head) < 0) {
426 gnttab_request_free_callback(
427 &info->callback,
428 blkif_restart_queue_callback,
429 info,
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200430 max_grefs);
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200431 return 1;
432 }
433 } else
434 new_persistent_gnts = 0;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700435
436 /* Fill out a communications ring structure. */
437 ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
438 id = get_id_from_freelist(info);
Jeremy Fitzhardingea945b982010-11-01 17:03:14 -0400439 info->shadow[id].request = req;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700440
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -0400441 if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) {
Li Dongyanged30bf32011-09-01 18:39:09 +0800442 ring_req->operation = BLKIF_OP_DISCARD;
Li Dongyanged30bf32011-09-01 18:39:09 +0800443 ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200444 ring_req->u.discard.id = id;
445 ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req);
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -0400446 if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard)
447 ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;
448 else
449 ring_req->u.discard.flag = 0;
Li Dongyanged30bf32011-09-01 18:39:09 +0800450 } else {
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200451 BUG_ON(info->max_indirect_segments == 0 &&
452 req->nr_phys_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
453 BUG_ON(info->max_indirect_segments &&
454 req->nr_phys_segments > info->max_indirect_segments);
Roger Pau Monneb7649152013-05-02 10:58:50 +0200455 nseg = blk_rq_map_sg(req->q, req, info->shadow[id].sg);
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200456 ring_req->u.rw.id = id;
457 if (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST) {
458 /*
459 * The indirect operation can only be a BLKIF_OP_READ or
460 * BLKIF_OP_WRITE
461 */
462 BUG_ON(req->cmd_flags & (REQ_FLUSH | REQ_FUA));
463 ring_req->operation = BLKIF_OP_INDIRECT;
464 ring_req->u.indirect.indirect_op = rq_data_dir(req) ?
465 BLKIF_OP_WRITE : BLKIF_OP_READ;
466 ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req);
467 ring_req->u.indirect.handle = info->handle;
468 ring_req->u.indirect.nr_segments = nseg;
469 } else {
470 ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req);
471 ring_req->u.rw.handle = info->handle;
472 ring_req->operation = rq_data_dir(req) ?
473 BLKIF_OP_WRITE : BLKIF_OP_READ;
474 if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
475 /*
476 * Ideally we can do an unordered flush-to-disk. In case the
477 * backend onlysupports barriers, use that. A barrier request
478 * a superset of FUA, so we can implement it the same
479 * way. (It's also a FLUSH+FUA, since it is
480 * guaranteed ordered WRT previous writes.)
481 */
482 ring_req->operation = info->flush_op;
483 }
484 ring_req->u.rw.nr_segments = nseg;
485 }
Roger Pau Monneb7649152013-05-02 10:58:50 +0200486 for_each_sg(info->shadow[id].sg, sg, nseg, i) {
Li Dongyanged30bf32011-09-01 18:39:09 +0800487 fsect = sg->offset >> 9;
488 lsect = fsect + (sg->length >> 9) - 1;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700489
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200490 if ((ring_req->operation == BLKIF_OP_INDIRECT) &&
491 (i % SEGS_PER_INDIRECT_FRAME == 0)) {
Tim Gardner427bfe02013-11-14 14:29:52 -0700492 unsigned long uninitialized_var(pfn);
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100493
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200494 if (segments)
495 kunmap_atomic(segments);
496
497 n = i / SEGS_PER_INDIRECT_FRAME;
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100498 if (!info->feature_persistent) {
499 struct page *indirect_page;
500
501 /* Fetch a pre-allocated page to use for indirect grefs */
502 BUG_ON(list_empty(&info->indirect_pages));
503 indirect_page = list_first_entry(&info->indirect_pages,
504 struct page, lru);
505 list_del(&indirect_page->lru);
506 pfn = page_to_pfn(indirect_page);
507 }
508 gnt_list_entry = get_grant(&gref_head, pfn, info);
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200509 info->shadow[id].indirect_grants[n] = gnt_list_entry;
510 segments = kmap_atomic(pfn_to_page(gnt_list_entry->pfn));
511 ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref;
512 }
513
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100514 gnt_list_entry = get_grant(&gref_head, page_to_pfn(sg_page(sg)), info);
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100515 ref = gnt_list_entry->gref;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200516
517 info->shadow[id].grants_used[i] = gnt_list_entry;
518
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100519 if (rq_data_dir(req) && info->feature_persistent) {
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200520 char *bvec_data;
521 void *shared_data;
522
523 BUG_ON(sg->offset + sg->length > PAGE_SIZE);
524
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200525 shared_data = kmap_atomic(pfn_to_page(gnt_list_entry->pfn));
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200526 bvec_data = kmap_atomic(sg_page(sg));
527
528 /*
529 * this does not wipe data stored outside the
530 * range sg->offset..sg->offset+sg->length.
531 * Therefore, blkback *could* see data from
532 * previous requests. This is OK as long as
533 * persistent grants are shared with just one
534 * domain. It may need refactoring if this
535 * changes
536 */
537 memcpy(shared_data + sg->offset,
538 bvec_data + sg->offset,
539 sg->length);
540
541 kunmap_atomic(bvec_data);
542 kunmap_atomic(shared_data);
543 }
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200544 if (ring_req->operation != BLKIF_OP_INDIRECT) {
545 ring_req->u.rw.seg[i] =
546 (struct blkif_request_segment) {
547 .gref = ref,
548 .first_sect = fsect,
549 .last_sect = lsect };
550 } else {
551 n = i % SEGS_PER_INDIRECT_FRAME;
552 segments[n] =
553 (struct blkif_request_segment_aligned) {
554 .gref = ref,
555 .first_sect = fsect,
556 .last_sect = lsect };
557 }
Li Dongyanged30bf32011-09-01 18:39:09 +0800558 }
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200559 if (segments)
560 kunmap_atomic(segments);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700561 }
562
563 info->ring.req_prod_pvt++;
564
565 /* Keep a private copy so we can reissue requests when recovering. */
566 info->shadow[id].req = *ring_req;
567
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200568 if (new_persistent_gnts)
569 gnttab_free_grant_references(gref_head);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700570
571 return 0;
572}
573
574
575static inline void flush_requests(struct blkfront_info *info)
576{
577 int notify;
578
579 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify);
580
581 if (notify)
582 notify_remote_via_irq(info->irq);
583}
584
585/*
586 * do_blkif_request
587 * read a block; request is in a request queue
588 */
Jens Axboe165125e2007-07-24 09:28:11 +0200589static void do_blkif_request(struct request_queue *rq)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700590{
591 struct blkfront_info *info = NULL;
592 struct request *req;
593 int queued;
594
595 pr_debug("Entered do_blkif_request\n");
596
597 queued = 0;
598
Tejun Heo9934c8c2009-05-08 11:54:16 +0900599 while ((req = blk_peek_request(rq)) != NULL) {
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700600 info = req->rq_disk->private_data;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700601
602 if (RING_FULL(&info->ring))
603 goto wait;
604
Tejun Heo9934c8c2009-05-08 11:54:16 +0900605 blk_start_request(req);
Tejun Heo296b2f62009-05-08 11:54:15 +0900606
Konrad Rzeszutek Wilkd11e6152011-09-16 15:15:14 -0400607 if ((req->cmd_type != REQ_TYPE_FS) ||
608 ((req->cmd_flags & (REQ_FLUSH | REQ_FUA)) &&
609 !info->flush_op)) {
Tejun Heo296b2f62009-05-08 11:54:15 +0900610 __blk_end_request_all(req, -EIO);
611 continue;
612 }
613
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700614 pr_debug("do_blk_req %p: cmd %p, sec %lx, "
Tejun Heo83096eb2009-05-07 22:24:39 +0900615 "(%u/%u) buffer:%p [%s]\n",
616 req, req->cmd, (unsigned long)blk_rq_pos(req),
617 blk_rq_cur_sectors(req), blk_rq_sectors(req),
618 req->buffer, rq_data_dir(req) ? "write" : "read");
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700619
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700620 if (blkif_queue_request(req)) {
621 blk_requeue_request(rq, req);
622wait:
623 /* Avoid pointless unplugs. */
624 blk_stop_queue(rq);
625 break;
626 }
627
628 queued++;
629 }
630
631 if (queued != 0)
632 flush_requests(info);
633}
634
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200635static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
Stefan Bader7c4d7d72013-05-13 16:28:15 +0200636 unsigned int physical_sector_size,
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200637 unsigned int segments)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700638{
Jens Axboe165125e2007-07-24 09:28:11 +0200639 struct request_queue *rq;
Li Dongyanged30bf32011-09-01 18:39:09 +0800640 struct blkfront_info *info = gd->private_data;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700641
Steven Noonan34678112012-02-17 12:04:44 -0800642 rq = blk_init_queue(do_blkif_request, &info->io_lock);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700643 if (rq == NULL)
644 return -1;
645
Fernando Luis Vázquez Cao66d352e2008-10-27 18:45:54 +0900646 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700647
Li Dongyanged30bf32011-09-01 18:39:09 +0800648 if (info->feature_discard) {
649 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
650 blk_queue_max_discard_sectors(rq, get_capacity(gd));
651 rq->limits.discard_granularity = info->discard_granularity;
652 rq->limits.discard_alignment = info->discard_alignment;
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -0400653 if (info->feature_secdiscard)
654 queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, rq);
Li Dongyanged30bf32011-09-01 18:39:09 +0800655 }
656
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700657 /* Hard sector size and max sectors impersonate the equiv. hardware. */
Martin K. Petersene1defc42009-05-22 17:17:49 -0400658 blk_queue_logical_block_size(rq, sector_size);
Stefan Bader7c4d7d72013-05-13 16:28:15 +0200659 blk_queue_physical_block_size(rq, physical_sector_size);
Roger Pau Monne294caaf2013-06-21 12:56:54 +0200660 blk_queue_max_hw_sectors(rq, (segments * PAGE_SIZE) / 512);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700661
662 /* Each segment in a request is up to an aligned page in size. */
663 blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
664 blk_queue_max_segment_size(rq, PAGE_SIZE);
665
666 /* Ensure a merged request will fit in a single I/O ring slot. */
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200667 blk_queue_max_segments(rq, segments);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700668
669 /* Make sure buffer addresses are sector-aligned. */
670 blk_queue_dma_alignment(rq, 511);
671
Ian Campbell1c91fe12008-06-17 10:47:08 +0200672 /* Make sure we don't use bounce buffers. */
673 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
674
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700675 gd->queue = rq;
676
677 return 0;
678}
679
680
Tejun Heo4913efe2010-09-03 11:56:16 +0200681static void xlvbd_flush(struct blkfront_info *info)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700682{
Tejun Heo4913efe2010-09-03 11:56:16 +0200683 blk_queue_flush(info->rq, info->feature_flush);
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200684 printk(KERN_INFO "blkfront: %s: %s: %s %s %s %s %s\n",
Tejun Heo4913efe2010-09-03 11:56:16 +0200685 info->gd->disk_name,
Konrad Rzeszutek Wilkedf6ef52011-05-03 12:01:11 -0400686 info->flush_op == BLKIF_OP_WRITE_BARRIER ?
687 "barrier" : (info->flush_op == BLKIF_OP_FLUSH_DISKCACHE ?
688 "flush diskcache" : "barrier or flush"),
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200689 info->feature_flush ? "enabled;" : "disabled;",
690 "persistent grants:",
691 info->feature_persistent ? "enabled;" : "disabled;",
692 "indirect descriptors:",
693 info->max_indirect_segments ? "enabled;" : "disabled;");
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700694}
695
Stefano Stabellinic80a4202010-12-02 17:55:00 +0000696static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
697{
698 int major;
699 major = BLKIF_MAJOR(vdevice);
700 *minor = BLKIF_MINOR(vdevice);
701 switch (major) {
702 case XEN_IDE0_MAJOR:
703 *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET;
704 *minor = ((*minor / 64) * PARTS_PER_DISK) +
705 EMULATED_HD_DISK_MINOR_OFFSET;
706 break;
707 case XEN_IDE1_MAJOR:
708 *offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET;
709 *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) +
710 EMULATED_HD_DISK_MINOR_OFFSET;
711 break;
712 case XEN_SCSI_DISK0_MAJOR:
713 *offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET;
714 *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET;
715 break;
716 case XEN_SCSI_DISK1_MAJOR:
717 case XEN_SCSI_DISK2_MAJOR:
718 case XEN_SCSI_DISK3_MAJOR:
719 case XEN_SCSI_DISK4_MAJOR:
720 case XEN_SCSI_DISK5_MAJOR:
721 case XEN_SCSI_DISK6_MAJOR:
722 case XEN_SCSI_DISK7_MAJOR:
723 *offset = (*minor / PARTS_PER_DISK) +
724 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) +
725 EMULATED_SD_DISK_NAME_OFFSET;
726 *minor = *minor +
727 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) +
728 EMULATED_SD_DISK_MINOR_OFFSET;
729 break;
730 case XEN_SCSI_DISK8_MAJOR:
731 case XEN_SCSI_DISK9_MAJOR:
732 case XEN_SCSI_DISK10_MAJOR:
733 case XEN_SCSI_DISK11_MAJOR:
734 case XEN_SCSI_DISK12_MAJOR:
735 case XEN_SCSI_DISK13_MAJOR:
736 case XEN_SCSI_DISK14_MAJOR:
737 case XEN_SCSI_DISK15_MAJOR:
738 *offset = (*minor / PARTS_PER_DISK) +
739 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) +
740 EMULATED_SD_DISK_NAME_OFFSET;
741 *minor = *minor +
742 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) +
743 EMULATED_SD_DISK_MINOR_OFFSET;
744 break;
745 case XENVBD_MAJOR:
746 *offset = *minor / PARTS_PER_DISK;
747 break;
748 default:
749 printk(KERN_WARNING "blkfront: your disk configuration is "
750 "incorrect, please use an xvd device instead\n");
751 return -ENODEV;
752 }
753 return 0;
754}
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700755
Jan Beuliche77c78c2012-04-05 16:37:22 +0100756static char *encode_disk_name(char *ptr, unsigned int n)
757{
758 if (n >= 26)
759 ptr = encode_disk_name(ptr, n / 26 - 1);
760 *ptr = 'a' + n % 26;
761 return ptr + 1;
762}
763
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700764static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
765 struct blkfront_info *info,
Stefan Bader7c4d7d72013-05-13 16:28:15 +0200766 u16 vdisk_info, u16 sector_size,
767 unsigned int physical_sector_size)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700768{
769 struct gendisk *gd;
770 int nr_minors = 1;
Stefano Stabellinic80a4202010-12-02 17:55:00 +0000771 int err;
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700772 unsigned int offset;
773 int minor;
774 int nr_parts;
Jan Beuliche77c78c2012-04-05 16:37:22 +0100775 char *ptr;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700776
777 BUG_ON(info->gd != NULL);
778 BUG_ON(info->rq != NULL);
779
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700780 if ((info->vdevice>>EXT_SHIFT) > 1) {
781 /* this is above the extended range; something is wrong */
782 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice);
783 return -ENODEV;
784 }
785
786 if (!VDEV_IS_EXTENDED(info->vdevice)) {
Stefano Stabellinic80a4202010-12-02 17:55:00 +0000787 err = xen_translate_vdev(info->vdevice, &minor, &offset);
788 if (err)
789 return err;
790 nr_parts = PARTS_PER_DISK;
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700791 } else {
792 minor = BLKIF_MINOR_EXT(info->vdevice);
793 nr_parts = PARTS_PER_EXT_DISK;
Stefano Stabellinic80a4202010-12-02 17:55:00 +0000794 offset = minor / nr_parts;
Stefan Bader89153b52011-07-14 15:30:37 +0200795 if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4)
Stefano Stabellinic80a4202010-12-02 17:55:00 +0000796 printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with "
797 "emulated IDE disks,\n\t choose an xvd device name"
798 "from xvde on\n", info->vdevice);
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700799 }
Jan Beuliche77c78c2012-04-05 16:37:22 +0100800 if (minor >> MINORBITS) {
801 pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n",
802 info->vdevice, minor);
803 return -ENODEV;
804 }
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700805
806 if ((minor % nr_parts) == 0)
807 nr_minors = nr_parts;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700808
Jan Beulich0e345822010-08-07 18:28:55 +0200809 err = xlbd_reserve_minors(minor, nr_minors);
810 if (err)
811 goto out;
812 err = -ENODEV;
813
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700814 gd = alloc_disk(nr_minors);
815 if (gd == NULL)
Jan Beulich0e345822010-08-07 18:28:55 +0200816 goto release;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700817
Jan Beuliche77c78c2012-04-05 16:37:22 +0100818 strcpy(gd->disk_name, DEV_NAME);
819 ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset);
820 BUG_ON(ptr >= gd->disk_name + DISK_NAME_LEN);
821 if (nr_minors > 1)
822 *ptr = 0;
823 else
824 snprintf(ptr, gd->disk_name + DISK_NAME_LEN - ptr,
825 "%d", minor & (nr_parts - 1));
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700826
827 gd->major = XENVBD_MAJOR;
828 gd->first_minor = minor;
829 gd->fops = &xlvbd_block_fops;
830 gd->private_data = info;
831 gd->driverfs_dev = &(info->xbdev->dev);
832 set_capacity(gd, capacity);
833
Stefan Bader7c4d7d72013-05-13 16:28:15 +0200834 if (xlvbd_init_blk_queue(gd, sector_size, physical_sector_size,
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200835 info->max_indirect_segments ? :
836 BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700837 del_gendisk(gd);
Jan Beulich0e345822010-08-07 18:28:55 +0200838 goto release;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700839 }
840
841 info->rq = gd->queue;
842 info->gd = gd;
843
Tejun Heo4913efe2010-09-03 11:56:16 +0200844 xlvbd_flush(info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700845
846 if (vdisk_info & VDISK_READONLY)
847 set_disk_ro(gd, 1);
848
849 if (vdisk_info & VDISK_REMOVABLE)
850 gd->flags |= GENHD_FL_REMOVABLE;
851
852 if (vdisk_info & VDISK_CDROM)
853 gd->flags |= GENHD_FL_CD;
854
855 return 0;
856
Jan Beulich0e345822010-08-07 18:28:55 +0200857 release:
858 xlbd_release_minors(minor, nr_minors);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700859 out:
860 return err;
861}
862
Daniel Stoddena66b5ae2010-08-07 18:33:17 +0200863static void xlvbd_release_gendisk(struct blkfront_info *info)
864{
865 unsigned int minor, nr_minors;
866 unsigned long flags;
867
868 if (info->rq == NULL)
869 return;
870
Steven Noonan34678112012-02-17 12:04:44 -0800871 spin_lock_irqsave(&info->io_lock, flags);
Daniel Stoddena66b5ae2010-08-07 18:33:17 +0200872
873 /* No more blkif_request(). */
874 blk_stop_queue(info->rq);
875
876 /* No more gnttab callback work. */
877 gnttab_cancel_free_callback(&info->callback);
Steven Noonan34678112012-02-17 12:04:44 -0800878 spin_unlock_irqrestore(&info->io_lock, flags);
Daniel Stoddena66b5ae2010-08-07 18:33:17 +0200879
880 /* Flush gnttab callback work. Must be done with no locks held. */
Tejun Heo43829732012-08-20 14:51:24 -0700881 flush_work(&info->work);
Daniel Stoddena66b5ae2010-08-07 18:33:17 +0200882
883 del_gendisk(info->gd);
884
885 minor = info->gd->first_minor;
886 nr_minors = info->gd->minors;
887 xlbd_release_minors(minor, nr_minors);
888
889 blk_cleanup_queue(info->rq);
890 info->rq = NULL;
891
892 put_disk(info->gd);
893 info->gd = NULL;
894}
895
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700896static void kick_pending_request_queues(struct blkfront_info *info)
897{
898 if (!RING_FULL(&info->ring)) {
899 /* Re-enable calldowns. */
900 blk_start_queue(info->rq);
901 /* Kick things off immediately. */
902 do_blkif_request(info->rq);
903 }
904}
905
906static void blkif_restart_queue(struct work_struct *work)
907{
908 struct blkfront_info *info = container_of(work, struct blkfront_info, work);
909
Steven Noonan34678112012-02-17 12:04:44 -0800910 spin_lock_irq(&info->io_lock);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700911 if (info->connected == BLKIF_STATE_CONNECTED)
912 kick_pending_request_queues(info);
Steven Noonan34678112012-02-17 12:04:44 -0800913 spin_unlock_irq(&info->io_lock);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700914}
915
916static void blkif_free(struct blkfront_info *info, int suspend)
917{
Roger Pau Monne155b7ed2013-03-18 17:49:34 +0100918 struct grant *persistent_gnt;
919 struct grant *n;
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200920 int i, j, segs;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200921
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700922 /* Prevent new requests being issued until we fix things up. */
Steven Noonan34678112012-02-17 12:04:44 -0800923 spin_lock_irq(&info->io_lock);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700924 info->connected = suspend ?
925 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
926 /* No more blkif_request(). */
927 if (info->rq)
928 blk_stop_queue(info->rq);
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200929
930 /* Remove all persistent grants */
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100931 if (!list_empty(&info->grants)) {
Roger Pau Monne155b7ed2013-03-18 17:49:34 +0100932 list_for_each_entry_safe(persistent_gnt, n,
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100933 &info->grants, node) {
Roger Pau Monne155b7ed2013-03-18 17:49:34 +0100934 list_del(&persistent_gnt->node);
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100935 if (persistent_gnt->gref != GRANT_INVALID_REF) {
936 gnttab_end_foreign_access(persistent_gnt->gref,
937 0, 0UL);
938 info->persistent_gnts_c--;
939 }
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100940 if (info->feature_persistent)
941 __free_page(pfn_to_page(persistent_gnt->pfn));
Roger Pau Monne155b7ed2013-03-18 17:49:34 +0100942 kfree(persistent_gnt);
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200943 }
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200944 }
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100945 BUG_ON(info->persistent_gnts_c != 0);
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200946
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100947 /*
948 * Remove indirect pages, this only happens when using indirect
949 * descriptors but not persistent grants
950 */
951 if (!list_empty(&info->indirect_pages)) {
952 struct page *indirect_page, *n;
953
954 BUG_ON(info->feature_persistent);
955 list_for_each_entry_safe(indirect_page, n, &info->indirect_pages, lru) {
956 list_del(&indirect_page->lru);
957 __free_page(indirect_page);
958 }
959 }
960
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200961 for (i = 0; i < BLK_RING_SIZE; i++) {
962 /*
963 * Clear persistent grants present in requests already
964 * on the shared ring
965 */
966 if (!info->shadow[i].request)
967 goto free_shadow;
968
969 segs = info->shadow[i].req.operation == BLKIF_OP_INDIRECT ?
970 info->shadow[i].req.u.indirect.nr_segments :
971 info->shadow[i].req.u.rw.nr_segments;
972 for (j = 0; j < segs; j++) {
973 persistent_gnt = info->shadow[i].grants_used[j];
974 gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100975 if (info->feature_persistent)
976 __free_page(pfn_to_page(persistent_gnt->pfn));
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200977 kfree(persistent_gnt);
978 }
979
980 if (info->shadow[i].req.operation != BLKIF_OP_INDIRECT)
981 /*
982 * If this is not an indirect operation don't try to
983 * free indirect segments
984 */
985 goto free_shadow;
986
987 for (j = 0; j < INDIRECT_GREFS(segs); j++) {
988 persistent_gnt = info->shadow[i].indirect_grants[j];
989 gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
990 __free_page(pfn_to_page(persistent_gnt->pfn));
991 kfree(persistent_gnt);
992 }
993
994free_shadow:
995 kfree(info->shadow[i].grants_used);
996 info->shadow[i].grants_used = NULL;
997 kfree(info->shadow[i].indirect_grants);
998 info->shadow[i].indirect_grants = NULL;
Roger Pau Monneb7649152013-05-02 10:58:50 +0200999 kfree(info->shadow[i].sg);
1000 info->shadow[i].sg = NULL;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001001 }
1002
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001003 /* No more gnttab callback work. */
1004 gnttab_cancel_free_callback(&info->callback);
Steven Noonan34678112012-02-17 12:04:44 -08001005 spin_unlock_irq(&info->io_lock);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001006
1007 /* Flush gnttab callback work. Must be done with no locks held. */
Tejun Heo43829732012-08-20 14:51:24 -07001008 flush_work(&info->work);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001009
1010 /* Free resources associated with old device channel. */
1011 if (info->ring_ref != GRANT_INVALID_REF) {
1012 gnttab_end_foreign_access(info->ring_ref, 0,
1013 (unsigned long)info->ring.sring);
1014 info->ring_ref = GRANT_INVALID_REF;
1015 info->ring.sring = NULL;
1016 }
1017 if (info->irq)
1018 unbind_from_irqhandler(info->irq, info);
1019 info->evtchn = info->irq = 0;
1020
1021}
1022
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001023static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
1024 struct blkif_response *bret)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001025{
Roger Pau Monned62f6912012-12-07 19:00:31 +01001026 int i = 0;
Roger Pau Monneb7649152013-05-02 10:58:50 +02001027 struct scatterlist *sg;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001028 char *bvec_data;
1029 void *shared_data;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001030 int nseg;
1031
1032 nseg = s->req.operation == BLKIF_OP_INDIRECT ?
1033 s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001034
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001035 if (bret->operation == BLKIF_OP_READ && info->feature_persistent) {
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001036 /*
1037 * Copy the data received from the backend into the bvec.
1038 * Since bv_offset can be different than 0, and bv_len different
1039 * than PAGE_SIZE, we have to keep track of the current offset,
1040 * to be sure we are copying the data from the right shared page.
1041 */
Roger Pau Monneb7649152013-05-02 10:58:50 +02001042 for_each_sg(s->sg, sg, nseg, i) {
1043 BUG_ON(sg->offset + sg->length > PAGE_SIZE);
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001044 shared_data = kmap_atomic(
1045 pfn_to_page(s->grants_used[i]->pfn));
Roger Pau Monneb7649152013-05-02 10:58:50 +02001046 bvec_data = kmap_atomic(sg_page(sg));
1047 memcpy(bvec_data + sg->offset,
1048 shared_data + sg->offset,
1049 sg->length);
1050 kunmap_atomic(bvec_data);
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001051 kunmap_atomic(shared_data);
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001052 }
1053 }
1054 /* Add the persistent grant into the list of free grants */
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001055 for (i = 0; i < nseg; i++) {
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001056 if (gnttab_query_foreign_access(s->grants_used[i]->gref)) {
1057 /*
1058 * If the grant is still mapped by the backend (the
1059 * backend has chosen to make this grant persistent)
1060 * we add it at the head of the list, so it will be
1061 * reused first.
1062 */
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001063 if (!info->feature_persistent)
1064 pr_alert_ratelimited("backed has not unmapped grant: %u\n",
1065 s->grants_used[i]->gref);
1066 list_add(&s->grants_used[i]->node, &info->grants);
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001067 info->persistent_gnts_c++;
1068 } else {
1069 /*
1070 * If the grant is not mapped by the backend we end the
1071 * foreign access and add it to the tail of the list,
1072 * so it will not be picked again unless we run out of
1073 * persistent grants.
1074 */
1075 gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL);
1076 s->grants_used[i]->gref = GRANT_INVALID_REF;
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001077 list_add_tail(&s->grants_used[i]->node, &info->grants);
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001078 }
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001079 }
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001080 if (s->req.operation == BLKIF_OP_INDIRECT) {
1081 for (i = 0; i < INDIRECT_GREFS(nseg); i++) {
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001082 if (gnttab_query_foreign_access(s->indirect_grants[i]->gref)) {
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001083 if (!info->feature_persistent)
1084 pr_alert_ratelimited("backed has not unmapped grant: %u\n",
1085 s->indirect_grants[i]->gref);
1086 list_add(&s->indirect_grants[i]->node, &info->grants);
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001087 info->persistent_gnts_c++;
1088 } else {
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001089 struct page *indirect_page;
1090
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001091 gnttab_end_foreign_access(s->indirect_grants[i]->gref, 0, 0UL);
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001092 /*
1093 * Add the used indirect page back to the list of
1094 * available pages for indirect grefs.
1095 */
1096 indirect_page = pfn_to_page(s->indirect_grants[i]->pfn);
1097 list_add(&indirect_page->lru, &info->indirect_pages);
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001098 s->indirect_grants[i]->gref = GRANT_INVALID_REF;
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001099 list_add_tail(&s->indirect_grants[i]->node, &info->grants);
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001100 }
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001101 }
1102 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001103}
1104
1105static irqreturn_t blkif_interrupt(int irq, void *dev_id)
1106{
1107 struct request *req;
1108 struct blkif_response *bret;
1109 RING_IDX i, rp;
1110 unsigned long flags;
1111 struct blkfront_info *info = (struct blkfront_info *)dev_id;
Kiyoshi Uedaf530f0362007-12-11 17:47:36 -05001112 int error;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001113
Steven Noonan34678112012-02-17 12:04:44 -08001114 spin_lock_irqsave(&info->io_lock, flags);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001115
1116 if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
Steven Noonan34678112012-02-17 12:04:44 -08001117 spin_unlock_irqrestore(&info->io_lock, flags);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001118 return IRQ_HANDLED;
1119 }
1120
1121 again:
1122 rp = info->ring.sring->rsp_prod;
1123 rmb(); /* Ensure we see queued responses up to 'rp'. */
1124
1125 for (i = info->ring.rsp_cons; i != rp; i++) {
1126 unsigned long id;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001127
1128 bret = RING_GET_RESPONSE(&info->ring, i);
1129 id = bret->id;
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -04001130 /*
1131 * The backend has messed up and given us an id that we would
1132 * never have given to it (we stamp it up to BLK_RING_SIZE -
1133 * look in get_id_from_freelist.
1134 */
1135 if (id >= BLK_RING_SIZE) {
1136 WARN(1, "%s: response to %s has incorrect id (%ld)\n",
1137 info->gd->disk_name, op_name(bret->operation), id);
1138 /* We can't safely get the 'struct request' as
1139 * the id is busted. */
1140 continue;
1141 }
Jeremy Fitzhardingea945b982010-11-01 17:03:14 -04001142 req = info->shadow[id].request;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001143
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -04001144 if (bret->operation != BLKIF_OP_DISCARD)
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001145 blkif_completion(&info->shadow[id], info, bret);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001146
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -04001147 if (add_id_to_freelist(info, id)) {
1148 WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n",
1149 info->gd->disk_name, op_name(bret->operation), id);
1150 continue;
1151 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001152
Kiyoshi Uedaf530f0362007-12-11 17:47:36 -05001153 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001154 switch (bret->operation) {
Li Dongyanged30bf32011-09-01 18:39:09 +08001155 case BLKIF_OP_DISCARD:
1156 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
1157 struct request_queue *rq = info->rq;
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -04001158 printk(KERN_WARNING "blkfront: %s: %s op failed\n",
1159 info->gd->disk_name, op_name(bret->operation));
Li Dongyanged30bf32011-09-01 18:39:09 +08001160 error = -EOPNOTSUPP;
1161 info->feature_discard = 0;
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -04001162 info->feature_secdiscard = 0;
Li Dongyanged30bf32011-09-01 18:39:09 +08001163 queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -04001164 queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq);
Li Dongyanged30bf32011-09-01 18:39:09 +08001165 }
1166 __blk_end_request_all(req, error);
1167 break;
Konrad Rzeszutek Wilkedf6ef52011-05-03 12:01:11 -04001168 case BLKIF_OP_FLUSH_DISKCACHE:
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001169 case BLKIF_OP_WRITE_BARRIER:
1170 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -04001171 printk(KERN_WARNING "blkfront: %s: %s op failed\n",
1172 info->gd->disk_name, op_name(bret->operation));
Kiyoshi Uedaf530f0362007-12-11 17:47:36 -05001173 error = -EOPNOTSUPP;
Jeremy Fitzhardingedcb8bae2010-11-02 11:55:58 -04001174 }
1175 if (unlikely(bret->status == BLKIF_RSP_ERROR &&
Konrad Rzeszutek Wilk97e36832011-10-12 12:12:36 -04001176 info->shadow[id].req.u.rw.nr_segments == 0)) {
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -04001177 printk(KERN_WARNING "blkfront: %s: empty %s op failed\n",
1178 info->gd->disk_name, op_name(bret->operation));
Jeremy Fitzhardingedcb8bae2010-11-02 11:55:58 -04001179 error = -EOPNOTSUPP;
1180 }
1181 if (unlikely(error)) {
1182 if (error == -EOPNOTSUPP)
1183 error = 0;
Tejun Heo4913efe2010-09-03 11:56:16 +02001184 info->feature_flush = 0;
Konrad Rzeszutek Wilkedf6ef52011-05-03 12:01:11 -04001185 info->flush_op = 0;
Tejun Heo4913efe2010-09-03 11:56:16 +02001186 xlvbd_flush(info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001187 }
1188 /* fall through */
1189 case BLKIF_OP_READ:
1190 case BLKIF_OP_WRITE:
1191 if (unlikely(bret->status != BLKIF_RSP_OKAY))
1192 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
1193 "request: %x\n", bret->status);
1194
Tejun Heo40cbbb72009-04-23 11:05:19 +09001195 __blk_end_request_all(req, error);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001196 break;
1197 default:
1198 BUG();
1199 }
1200 }
1201
1202 info->ring.rsp_cons = i;
1203
1204 if (i != info->ring.req_prod_pvt) {
1205 int more_to_do;
1206 RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
1207 if (more_to_do)
1208 goto again;
1209 } else
1210 info->ring.sring->rsp_event = i + 1;
1211
1212 kick_pending_request_queues(info);
1213
Steven Noonan34678112012-02-17 12:04:44 -08001214 spin_unlock_irqrestore(&info->io_lock, flags);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001215
1216 return IRQ_HANDLED;
1217}
1218
1219
1220static int setup_blkring(struct xenbus_device *dev,
1221 struct blkfront_info *info)
1222{
1223 struct blkif_sring *sring;
1224 int err;
1225
1226 info->ring_ref = GRANT_INVALID_REF;
1227
Ian Campbella144ff02008-06-17 10:47:08 +02001228 sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001229 if (!sring) {
1230 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
1231 return -ENOMEM;
1232 }
1233 SHARED_RING_INIT(sring);
1234 FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
1235
1236 err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
1237 if (err < 0) {
1238 free_page((unsigned long)sring);
1239 info->ring.sring = NULL;
1240 goto fail;
1241 }
1242 info->ring_ref = err;
1243
1244 err = xenbus_alloc_evtchn(dev, &info->evtchn);
1245 if (err)
1246 goto fail;
1247
Theodore Ts'o89c30f12012-07-17 13:46:19 -04001248 err = bind_evtchn_to_irqhandler(info->evtchn, blkif_interrupt, 0,
1249 "blkif", info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001250 if (err <= 0) {
1251 xenbus_dev_fatal(dev, err,
1252 "bind_evtchn_to_irqhandler failed");
1253 goto fail;
1254 }
1255 info->irq = err;
1256
1257 return 0;
1258fail:
1259 blkif_free(info, 0);
1260 return err;
1261}
1262
1263
1264/* Common code used when first setting up, and when resuming. */
Ian Campbell203fd612009-12-04 15:33:54 +00001265static int talk_to_blkback(struct xenbus_device *dev,
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001266 struct blkfront_info *info)
1267{
1268 const char *message = NULL;
1269 struct xenbus_transaction xbt;
1270 int err;
1271
1272 /* Create shared ring, alloc event channel. */
1273 err = setup_blkring(dev, info);
1274 if (err)
1275 goto out;
1276
1277again:
1278 err = xenbus_transaction_start(&xbt);
1279 if (err) {
1280 xenbus_dev_fatal(dev, err, "starting transaction");
1281 goto destroy_blkring;
1282 }
1283
1284 err = xenbus_printf(xbt, dev->nodename,
1285 "ring-ref", "%u", info->ring_ref);
1286 if (err) {
1287 message = "writing ring-ref";
1288 goto abort_transaction;
1289 }
1290 err = xenbus_printf(xbt, dev->nodename,
1291 "event-channel", "%u", info->evtchn);
1292 if (err) {
1293 message = "writing event-channel";
1294 goto abort_transaction;
1295 }
Markus Armbruster3e334232008-04-02 10:54:02 -07001296 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
1297 XEN_IO_PROTO_ABI_NATIVE);
1298 if (err) {
1299 message = "writing protocol";
1300 goto abort_transaction;
1301 }
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001302 err = xenbus_printf(xbt, dev->nodename,
Roger Pau Monnecb5bd4d2012-11-02 16:43:04 +01001303 "feature-persistent", "%u", 1);
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001304 if (err)
1305 dev_warn(&dev->dev,
1306 "writing persistent grants feature to xenbus");
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001307
1308 err = xenbus_transaction_end(xbt, 0);
1309 if (err) {
1310 if (err == -EAGAIN)
1311 goto again;
1312 xenbus_dev_fatal(dev, err, "completing transaction");
1313 goto destroy_blkring;
1314 }
1315
1316 xenbus_switch_state(dev, XenbusStateInitialised);
1317
1318 return 0;
1319
1320 abort_transaction:
1321 xenbus_transaction_end(xbt, 1);
1322 if (message)
1323 xenbus_dev_fatal(dev, err, "%s", message);
1324 destroy_blkring:
1325 blkif_free(info, 0);
1326 out:
1327 return err;
1328}
1329
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001330/**
1331 * Entry point to this code when a new device is created. Allocate the basic
1332 * structures and the ring buffer for communication with the backend, and
1333 * inform the backend of the appropriate details for those. Switch to
1334 * Initialised state.
1335 */
1336static int blkfront_probe(struct xenbus_device *dev,
1337 const struct xenbus_device_id *id)
1338{
1339 int err, vdevice, i;
1340 struct blkfront_info *info;
1341
1342 /* FIXME: Use dynamic device id if this is not set. */
1343 err = xenbus_scanf(XBT_NIL, dev->nodename,
1344 "virtual-device", "%i", &vdevice);
1345 if (err != 1) {
Chris Lalancette9246b5f2008-09-17 14:30:32 -07001346 /* go looking in the extended area instead */
1347 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext",
1348 "%i", &vdevice);
1349 if (err != 1) {
1350 xenbus_dev_fatal(dev, err, "reading virtual-device");
1351 return err;
1352 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001353 }
1354
Stefano Stabellinib98a4092010-07-29 14:53:16 +01001355 if (xen_hvm_domain()) {
1356 char *type;
1357 int len;
1358 /* no unplug has been done: do not hook devices != xen vbds */
Ian Campbell1dc7ce92010-08-23 11:59:29 +01001359 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) {
Stefano Stabellinib98a4092010-07-29 14:53:16 +01001360 int major;
Stefano Stabellinic1c54132010-05-14 12:44:30 +01001361
Stefano Stabellinib98a4092010-07-29 14:53:16 +01001362 if (!VDEV_IS_EXTENDED(vdevice))
1363 major = BLKIF_MAJOR(vdevice);
1364 else
1365 major = XENVBD_MAJOR;
Stefano Stabellinic1c54132010-05-14 12:44:30 +01001366
Stefano Stabellinib98a4092010-07-29 14:53:16 +01001367 if (major != XENVBD_MAJOR) {
1368 printk(KERN_INFO
1369 "%s: HVM does not support vbd %d as xen block device\n",
1370 __FUNCTION__, vdevice);
1371 return -ENODEV;
1372 }
1373 }
1374 /* do not create a PV cdrom device if we are an HVM guest */
1375 type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
1376 if (IS_ERR(type))
1377 return -ENODEV;
1378 if (strncmp(type, "cdrom", 5) == 0) {
1379 kfree(type);
Stefano Stabellinic1c54132010-05-14 12:44:30 +01001380 return -ENODEV;
1381 }
Stefano Stabellinib98a4092010-07-29 14:53:16 +01001382 kfree(type);
Stefano Stabellinic1c54132010-05-14 12:44:30 +01001383 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001384 info = kzalloc(sizeof(*info), GFP_KERNEL);
1385 if (!info) {
1386 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
1387 return -ENOMEM;
1388 }
1389
Daniel Stoddenb70f5fa2010-04-30 22:01:19 +00001390 mutex_init(&info->mutex);
Steven Noonan34678112012-02-17 12:04:44 -08001391 spin_lock_init(&info->io_lock);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001392 info->xbdev = dev;
1393 info->vdevice = vdevice;
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001394 INIT_LIST_HEAD(&info->grants);
1395 INIT_LIST_HEAD(&info->indirect_pages);
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001396 info->persistent_gnts_c = 0;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001397 info->connected = BLKIF_STATE_DISCONNECTED;
1398 INIT_WORK(&info->work, blkif_restart_queue);
1399
1400 for (i = 0; i < BLK_RING_SIZE; i++)
Konrad Rzeszutek Wilk97e36832011-10-12 12:12:36 -04001401 info->shadow[i].req.u.rw.id = i+1;
1402 info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001403
1404 /* Front end dir is a number, which is used as the id. */
1405 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
Greg Kroah-Hartmana1b4b122009-04-30 14:43:31 -07001406 dev_set_drvdata(&dev->dev, info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001407
Ian Campbell203fd612009-12-04 15:33:54 +00001408 err = talk_to_blkback(dev, info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001409 if (err) {
1410 kfree(info);
Greg Kroah-Hartmana1b4b122009-04-30 14:43:31 -07001411 dev_set_drvdata(&dev->dev, NULL);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001412 return err;
1413 }
1414
1415 return 0;
1416}
1417
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001418static void split_bio_end(struct bio *bio, int error)
1419{
1420 struct split_bio *split_bio = bio->bi_private;
1421
1422 if (error)
1423 split_bio->err = error;
1424
1425 if (atomic_dec_and_test(&split_bio->pending)) {
1426 split_bio->bio->bi_phys_segments = 0;
1427 bio_endio(split_bio->bio, split_bio->err);
1428 kfree(split_bio);
1429 }
1430 bio_put(bio);
1431}
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001432
1433static int blkif_recover(struct blkfront_info *info)
1434{
1435 int i;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001436 struct request *req, *n;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001437 struct blk_shadow *copy;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001438 int rc;
1439 struct bio *bio, *cloned_bio;
1440 struct bio_list bio_list, merge_bio;
1441 unsigned int segs, offset;
1442 int pending, size;
1443 struct split_bio *split_bio;
1444 struct list_head requests;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001445
1446 /* Stage 1: Make a safe copy of the shadow state. */
Mihnea Dobrescu-Balaur29d0b212013-03-11 13:23:36 +02001447 copy = kmemdup(info->shadow, sizeof(info->shadow),
Ian Campbella144ff02008-06-17 10:47:08 +02001448 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001449 if (!copy)
1450 return -ENOMEM;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001451
1452 /* Stage 2: Set up free list. */
1453 memset(&info->shadow, 0, sizeof(info->shadow));
1454 for (i = 0; i < BLK_RING_SIZE; i++)
Konrad Rzeszutek Wilk97e36832011-10-12 12:12:36 -04001455 info->shadow[i].req.u.rw.id = i+1;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001456 info->shadow_free = info->ring.req_prod_pvt;
Konrad Rzeszutek Wilk97e36832011-10-12 12:12:36 -04001457 info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001458
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001459 rc = blkfront_setup_indirect(info);
1460 if (rc) {
1461 kfree(copy);
1462 return rc;
1463 }
1464
1465 segs = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST;
1466 blk_queue_max_segments(info->rq, segs);
1467 bio_list_init(&bio_list);
1468 INIT_LIST_HEAD(&requests);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001469 for (i = 0; i < BLK_RING_SIZE; i++) {
1470 /* Not in use? */
Jeremy Fitzhardingea945b982010-11-01 17:03:14 -04001471 if (!copy[i].request)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001472 continue;
1473
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001474 /*
1475 * Get the bios in the request so we can re-queue them.
1476 */
1477 if (copy[i].request->cmd_flags &
1478 (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
1479 /*
1480 * Flush operations don't contain bios, so
1481 * we need to requeue the whole request
1482 */
1483 list_add(&copy[i].request->queuelist, &requests);
1484 continue;
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -04001485 }
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001486 merge_bio.head = copy[i].request->bio;
1487 merge_bio.tail = copy[i].request->biotail;
1488 bio_list_merge(&bio_list, &merge_bio);
1489 copy[i].request->bio = NULL;
1490 blk_put_request(copy[i].request);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001491 }
1492
1493 kfree(copy);
1494
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001495 /*
1496 * Empty the queue, this is important because we might have
1497 * requests in the queue with more segments than what we
1498 * can handle now.
1499 */
1500 spin_lock_irq(&info->io_lock);
1501 while ((req = blk_fetch_request(info->rq)) != NULL) {
1502 if (req->cmd_flags &
1503 (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
1504 list_add(&req->queuelist, &requests);
1505 continue;
1506 }
1507 merge_bio.head = req->bio;
1508 merge_bio.tail = req->biotail;
1509 bio_list_merge(&bio_list, &merge_bio);
1510 req->bio = NULL;
1511 if (req->cmd_flags & (REQ_FLUSH | REQ_FUA))
1512 pr_alert("diskcache flush request found!\n");
1513 __blk_put_request(info->rq, req);
1514 }
1515 spin_unlock_irq(&info->io_lock);
1516
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001517 xenbus_switch_state(info->xbdev, XenbusStateConnected);
1518
Steven Noonan34678112012-02-17 12:04:44 -08001519 spin_lock_irq(&info->io_lock);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001520
1521 /* Now safe for us to use the shared ring */
1522 info->connected = BLKIF_STATE_CONNECTED;
1523
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001524 /* Kick any other new requests queued since we resumed */
1525 kick_pending_request_queues(info);
1526
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001527 list_for_each_entry_safe(req, n, &requests, queuelist) {
1528 /* Requeue pending requests (flush or discard) */
1529 list_del_init(&req->queuelist);
1530 BUG_ON(req->nr_phys_segments > segs);
1531 blk_requeue_request(info->rq, req);
1532 }
Steven Noonan34678112012-02-17 12:04:44 -08001533 spin_unlock_irq(&info->io_lock);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001534
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001535 while ((bio = bio_list_pop(&bio_list)) != NULL) {
1536 /* Traverse the list of pending bios and re-queue them */
1537 if (bio_segments(bio) > segs) {
1538 /*
1539 * This bio has more segments than what we can
1540 * handle, we have to split it.
1541 */
1542 pending = (bio_segments(bio) + segs - 1) / segs;
1543 split_bio = kzalloc(sizeof(*split_bio), GFP_NOIO);
1544 BUG_ON(split_bio == NULL);
1545 atomic_set(&split_bio->pending, pending);
1546 split_bio->bio = bio;
1547 for (i = 0; i < pending; i++) {
1548 offset = (i * segs * PAGE_SIZE) >> 9;
1549 size = min((unsigned int)(segs * PAGE_SIZE) >> 9,
1550 (unsigned int)(bio->bi_size >> 9) - offset);
1551 cloned_bio = bio_clone(bio, GFP_NOIO);
1552 BUG_ON(cloned_bio == NULL);
Kent Overstreet6678d832013-08-07 11:14:32 -07001553 bio_trim(cloned_bio, offset, size);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001554 cloned_bio->bi_private = split_bio;
1555 cloned_bio->bi_end_io = split_bio_end;
1556 submit_bio(cloned_bio->bi_rw, cloned_bio);
1557 }
1558 /*
1559 * Now we have to wait for all those smaller bios to
1560 * end, so we can also end the "parent" bio.
1561 */
1562 continue;
1563 }
1564 /* We don't need to split this bio */
1565 submit_bio(bio->bi_rw, bio);
1566 }
1567
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001568 return 0;
1569}
1570
1571/**
1572 * We are reconnecting to the backend, due to a suspend/resume, or a backend
1573 * driver restart. We tear down our blkif structure and recreate it, but
1574 * leave the device-layer structures intact so that this is transparent to the
1575 * rest of the kernel.
1576 */
1577static int blkfront_resume(struct xenbus_device *dev)
1578{
Greg Kroah-Hartmana1b4b122009-04-30 14:43:31 -07001579 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001580 int err;
1581
1582 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
1583
1584 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
1585
Ian Campbell203fd612009-12-04 15:33:54 +00001586 err = talk_to_blkback(dev, info);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001587
1588 /*
1589 * We have to wait for the backend to switch to
1590 * connected state, since we want to read which
1591 * features it supports.
1592 */
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001593
1594 return err;
1595}
1596
Daniel Stoddenb70f5fa2010-04-30 22:01:19 +00001597static void
1598blkfront_closing(struct blkfront_info *info)
1599{
1600 struct xenbus_device *xbdev = info->xbdev;
1601 struct block_device *bdev = NULL;
1602
1603 mutex_lock(&info->mutex);
1604
1605 if (xbdev->state == XenbusStateClosing) {
1606 mutex_unlock(&info->mutex);
1607 return;
1608 }
1609
1610 if (info->gd)
1611 bdev = bdget_disk(info->gd, 0);
1612
1613 mutex_unlock(&info->mutex);
1614
1615 if (!bdev) {
1616 xenbus_frontend_closed(xbdev);
1617 return;
1618 }
1619
1620 mutex_lock(&bdev->bd_mutex);
1621
Daniel Stodden7b32d102010-04-30 22:01:23 +00001622 if (bdev->bd_openers) {
Daniel Stoddenb70f5fa2010-04-30 22:01:19 +00001623 xenbus_dev_error(xbdev, -EBUSY,
1624 "Device in use; refusing to close");
1625 xenbus_switch_state(xbdev, XenbusStateClosing);
1626 } else {
1627 xlvbd_release_gendisk(info);
1628 xenbus_frontend_closed(xbdev);
1629 }
1630
1631 mutex_unlock(&bdev->bd_mutex);
1632 bdput(bdev);
1633}
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001634
Li Dongyanged30bf32011-09-01 18:39:09 +08001635static void blkfront_setup_discard(struct blkfront_info *info)
1636{
1637 int err;
1638 char *type;
1639 unsigned int discard_granularity;
1640 unsigned int discard_alignment;
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -04001641 unsigned int discard_secure;
Li Dongyanged30bf32011-09-01 18:39:09 +08001642
1643 type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL);
1644 if (IS_ERR(type))
1645 return;
1646
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -04001647 info->feature_secdiscard = 0;
Li Dongyanged30bf32011-09-01 18:39:09 +08001648 if (strncmp(type, "phy", 3) == 0) {
1649 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1650 "discard-granularity", "%u", &discard_granularity,
1651 "discard-alignment", "%u", &discard_alignment,
1652 NULL);
1653 if (!err) {
1654 info->feature_discard = 1;
1655 info->discard_granularity = discard_granularity;
1656 info->discard_alignment = discard_alignment;
1657 }
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -04001658 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1659 "discard-secure", "%d", &discard_secure,
1660 NULL);
1661 if (!err)
1662 info->feature_secdiscard = discard_secure;
1663
Li Dongyanged30bf32011-09-01 18:39:09 +08001664 } else if (strncmp(type, "file", 4) == 0)
1665 info->feature_discard = 1;
1666
1667 kfree(type);
1668}
1669
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001670static int blkfront_setup_indirect(struct blkfront_info *info)
1671{
1672 unsigned int indirect_segments, segs;
1673 int err, i;
1674
1675 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1676 "feature-max-indirect-segments", "%u", &indirect_segments,
1677 NULL);
1678 if (err) {
1679 info->max_indirect_segments = 0;
1680 segs = BLKIF_MAX_SEGMENTS_PER_REQUEST;
1681 } else {
1682 info->max_indirect_segments = min(indirect_segments,
1683 xen_blkif_max_segments);
1684 segs = info->max_indirect_segments;
1685 }
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001686
1687 err = fill_grant_buffer(info, (segs + INDIRECT_GREFS(segs)) * BLK_RING_SIZE);
1688 if (err)
1689 goto out_of_memory;
1690
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001691 if (!info->feature_persistent && info->max_indirect_segments) {
1692 /*
1693 * We are using indirect descriptors but not persistent
1694 * grants, we need to allocate a set of pages that can be
1695 * used for mapping indirect grefs
1696 */
1697 int num = INDIRECT_GREFS(segs) * BLK_RING_SIZE;
1698
1699 BUG_ON(!list_empty(&info->indirect_pages));
1700 for (i = 0; i < num; i++) {
1701 struct page *indirect_page = alloc_page(GFP_NOIO);
1702 if (!indirect_page)
1703 goto out_of_memory;
1704 list_add(&indirect_page->lru, &info->indirect_pages);
1705 }
1706 }
1707
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001708 for (i = 0; i < BLK_RING_SIZE; i++) {
1709 info->shadow[i].grants_used = kzalloc(
1710 sizeof(info->shadow[i].grants_used[0]) * segs,
1711 GFP_NOIO);
Roger Pau Monneb7649152013-05-02 10:58:50 +02001712 info->shadow[i].sg = kzalloc(sizeof(info->shadow[i].sg[0]) * segs, GFP_NOIO);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001713 if (info->max_indirect_segments)
1714 info->shadow[i].indirect_grants = kzalloc(
1715 sizeof(info->shadow[i].indirect_grants[0]) *
1716 INDIRECT_GREFS(segs),
1717 GFP_NOIO);
1718 if ((info->shadow[i].grants_used == NULL) ||
Roger Pau Monneb7649152013-05-02 10:58:50 +02001719 (info->shadow[i].sg == NULL) ||
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001720 (info->max_indirect_segments &&
1721 (info->shadow[i].indirect_grants == NULL)))
1722 goto out_of_memory;
Roger Pau Monneb7649152013-05-02 10:58:50 +02001723 sg_init_table(info->shadow[i].sg, segs);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001724 }
1725
1726
1727 return 0;
1728
1729out_of_memory:
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001730 for (i = 0; i < BLK_RING_SIZE; i++) {
1731 kfree(info->shadow[i].grants_used);
1732 info->shadow[i].grants_used = NULL;
Roger Pau Monneb7649152013-05-02 10:58:50 +02001733 kfree(info->shadow[i].sg);
1734 info->shadow[i].sg = NULL;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001735 kfree(info->shadow[i].indirect_grants);
1736 info->shadow[i].indirect_grants = NULL;
1737 }
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001738 if (!list_empty(&info->indirect_pages)) {
1739 struct page *indirect_page, *n;
1740 list_for_each_entry_safe(indirect_page, n, &info->indirect_pages, lru) {
1741 list_del(&indirect_page->lru);
1742 __free_page(indirect_page);
1743 }
1744 }
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001745 return -ENOMEM;
1746}
1747
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001748/*
1749 * Invoked when the backend is finally 'ready' (and has told produced
1750 * the details about the physical device - #sectors, size, etc).
1751 */
1752static void blkfront_connect(struct blkfront_info *info)
1753{
1754 unsigned long long sectors;
1755 unsigned long sector_size;
Stefan Bader7c4d7d72013-05-13 16:28:15 +02001756 unsigned int physical_sector_size;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001757 unsigned int binfo;
1758 int err;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001759 int barrier, flush, discard, persistent;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001760
K. Y. Srinivasan1fa73be2010-03-11 13:42:26 -08001761 switch (info->connected) {
1762 case BLKIF_STATE_CONNECTED:
1763 /*
1764 * Potentially, the back-end may be signalling
1765 * a capacity change; update the capacity.
1766 */
1767 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1768 "sectors", "%Lu", &sectors);
1769 if (XENBUS_EXIST_ERR(err))
1770 return;
1771 printk(KERN_INFO "Setting capacity to %Lu\n",
1772 sectors);
1773 set_capacity(info->gd, sectors);
K. Y. Srinivasan2def1412010-03-18 15:00:54 -07001774 revalidate_disk(info->gd);
K. Y. Srinivasan1fa73be2010-03-11 13:42:26 -08001775
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001776 return;
K. Y. Srinivasan1fa73be2010-03-11 13:42:26 -08001777 case BLKIF_STATE_SUSPENDED:
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001778 /*
1779 * If we are recovering from suspension, we need to wait
1780 * for the backend to announce it's features before
1781 * reconnecting, at least we need to know if the backend
1782 * supports indirect descriptors, and how many.
1783 */
1784 blkif_recover(info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001785 return;
1786
Jeremy Fitzhardingeb4dddb42010-03-11 15:10:40 -08001787 default:
1788 break;
K. Y. Srinivasan1fa73be2010-03-11 13:42:26 -08001789 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001790
1791 dev_dbg(&info->xbdev->dev, "%s:%s.\n",
1792 __func__, info->xbdev->otherend);
1793
1794 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1795 "sectors", "%llu", &sectors,
1796 "info", "%u", &binfo,
1797 "sector-size", "%lu", &sector_size,
1798 NULL);
1799 if (err) {
1800 xenbus_dev_fatal(info->xbdev, err,
1801 "reading backend fields at %s",
1802 info->xbdev->otherend);
1803 return;
1804 }
1805
Stefan Bader7c4d7d72013-05-13 16:28:15 +02001806 /*
1807 * physcial-sector-size is a newer field, so old backends may not
1808 * provide this. Assume physical sector size to be the same as
1809 * sector_size in that case.
1810 */
1811 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1812 "physical-sector-size", "%u", &physical_sector_size);
1813 if (err != 1)
1814 physical_sector_size = sector_size;
1815
Konrad Rzeszutek Wilkedf6ef52011-05-03 12:01:11 -04001816 info->feature_flush = 0;
1817 info->flush_op = 0;
1818
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001819 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
Marek Marczykowski4352b472011-05-03 12:04:52 -04001820 "feature-barrier", "%d", &barrier,
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001821 NULL);
Jeremy Fitzhardinge7901d142010-07-28 10:49:29 -07001822
1823 /*
1824 * If there's no "feature-barrier" defined, then it means
1825 * we're dealing with a very old backend which writes
Tejun Heo4913efe2010-09-03 11:56:16 +02001826 * synchronously; nothing to do.
Jeremy Fitzhardinge7901d142010-07-28 10:49:29 -07001827 *
Tejun Heo6958f142010-09-03 11:56:16 +02001828 * If there are barriers, then we use flush.
Jeremy Fitzhardinge7901d142010-07-28 10:49:29 -07001829 */
Konrad Rzeszutek Wilkedf6ef52011-05-03 12:01:11 -04001830 if (!err && barrier) {
Jeremy Fitzhardingebe2f8372010-11-02 10:38:33 -04001831 info->feature_flush = REQ_FLUSH | REQ_FUA;
Konrad Rzeszutek Wilkedf6ef52011-05-03 12:01:11 -04001832 info->flush_op = BLKIF_OP_WRITE_BARRIER;
1833 }
1834 /*
1835 * And if there is "feature-flush-cache" use that above
1836 * barriers.
1837 */
1838 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1839 "feature-flush-cache", "%d", &flush,
1840 NULL);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001841
Konrad Rzeszutek Wilkedf6ef52011-05-03 12:01:11 -04001842 if (!err && flush) {
1843 info->feature_flush = REQ_FLUSH;
1844 info->flush_op = BLKIF_OP_FLUSH_DISKCACHE;
1845 }
Li Dongyanged30bf32011-09-01 18:39:09 +08001846
1847 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1848 "feature-discard", "%d", &discard,
1849 NULL);
1850
1851 if (!err && discard)
1852 blkfront_setup_discard(info);
1853
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001854 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
1855 "feature-persistent", "%u", &persistent,
1856 NULL);
1857 if (err)
1858 info->feature_persistent = 0;
1859 else
1860 info->feature_persistent = persistent;
1861
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001862 err = blkfront_setup_indirect(info);
1863 if (err) {
1864 xenbus_dev_fatal(info->xbdev, err, "setup_indirect at %s",
1865 info->xbdev->otherend);
1866 return;
1867 }
1868
Stefan Bader7c4d7d72013-05-13 16:28:15 +02001869 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size,
1870 physical_sector_size);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001871 if (err) {
1872 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
1873 info->xbdev->otherend);
1874 return;
1875 }
1876
1877 xenbus_switch_state(info->xbdev, XenbusStateConnected);
1878
1879 /* Kick pending requests. */
Steven Noonan34678112012-02-17 12:04:44 -08001880 spin_lock_irq(&info->io_lock);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001881 info->connected = BLKIF_STATE_CONNECTED;
1882 kick_pending_request_queues(info);
Steven Noonan34678112012-02-17 12:04:44 -08001883 spin_unlock_irq(&info->io_lock);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001884
1885 add_disk(info->gd);
Christian Limpach1d78d702008-04-02 10:54:04 -07001886
1887 info->is_ready = 1;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001888}
1889
1890/**
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001891 * Callback received when the backend's state changes.
1892 */
Ian Campbell203fd612009-12-04 15:33:54 +00001893static void blkback_changed(struct xenbus_device *dev,
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001894 enum xenbus_state backend_state)
1895{
Greg Kroah-Hartmana1b4b122009-04-30 14:43:31 -07001896 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001897
Ian Campbell203fd612009-12-04 15:33:54 +00001898 dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001899
1900 switch (backend_state) {
1901 case XenbusStateInitialising:
1902 case XenbusStateInitWait:
1903 case XenbusStateInitialised:
Noboru Iwamatsub78c9512009-10-13 17:22:29 -04001904 case XenbusStateReconfiguring:
1905 case XenbusStateReconfigured:
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001906 case XenbusStateUnknown:
1907 case XenbusStateClosed:
1908 break;
1909
1910 case XenbusStateConnected:
1911 blkfront_connect(info);
1912 break;
1913
1914 case XenbusStateClosing:
Daniel Stoddenb70f5fa2010-04-30 22:01:19 +00001915 blkfront_closing(info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001916 break;
1917 }
1918}
1919
Daniel Stoddenfa1bd352010-04-30 22:01:22 +00001920static int blkfront_remove(struct xenbus_device *xbdev)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001921{
Daniel Stoddenfa1bd352010-04-30 22:01:22 +00001922 struct blkfront_info *info = dev_get_drvdata(&xbdev->dev);
1923 struct block_device *bdev = NULL;
1924 struct gendisk *disk;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001925
Daniel Stoddenfa1bd352010-04-30 22:01:22 +00001926 dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001927
1928 blkif_free(info, 0);
1929
Daniel Stoddenfa1bd352010-04-30 22:01:22 +00001930 mutex_lock(&info->mutex);
1931
1932 disk = info->gd;
1933 if (disk)
1934 bdev = bdget_disk(disk, 0);
1935
1936 info->xbdev = NULL;
1937 mutex_unlock(&info->mutex);
1938
1939 if (!bdev) {
Jan Beulich0e345822010-08-07 18:28:55 +02001940 kfree(info);
Daniel Stoddenfa1bd352010-04-30 22:01:22 +00001941 return 0;
1942 }
1943
1944 /*
1945 * The xbdev was removed before we reached the Closed
1946 * state. See if it's safe to remove the disk. If the bdev
1947 * isn't closed yet, we let release take care of it.
1948 */
1949
1950 mutex_lock(&bdev->bd_mutex);
1951 info = disk->private_data;
1952
Daniel Stoddend54142c2010-08-07 18:51:21 +02001953 dev_warn(disk_to_dev(disk),
1954 "%s was hot-unplugged, %d stale handles\n",
1955 xbdev->nodename, bdev->bd_openers);
1956
Daniel Stodden7b32d102010-04-30 22:01:23 +00001957 if (info && !bdev->bd_openers) {
Daniel Stoddenfa1bd352010-04-30 22:01:22 +00001958 xlvbd_release_gendisk(info);
1959 disk->private_data = NULL;
1960 kfree(info);
1961 }
1962
1963 mutex_unlock(&bdev->bd_mutex);
1964 bdput(bdev);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001965
1966 return 0;
1967}
1968
Christian Limpach1d78d702008-04-02 10:54:04 -07001969static int blkfront_is_ready(struct xenbus_device *dev)
1970{
Greg Kroah-Hartmana1b4b122009-04-30 14:43:31 -07001971 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
Christian Limpach1d78d702008-04-02 10:54:04 -07001972
Jan Beulich5d7ed202010-08-07 18:31:12 +02001973 return info->is_ready && info->xbdev;
Christian Limpach1d78d702008-04-02 10:54:04 -07001974}
1975
Al Viroa63c8482008-03-02 10:23:47 -05001976static int blkif_open(struct block_device *bdev, fmode_t mode)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001977{
Daniel Stodden13961742010-08-07 18:36:53 +02001978 struct gendisk *disk = bdev->bd_disk;
1979 struct blkfront_info *info;
1980 int err = 0;
Arnd Bergmann6e9624b2010-08-07 18:25:34 +02001981
Arnd Bergmann2a48fc02010-06-02 14:28:52 +02001982 mutex_lock(&blkfront_mutex);
Arnd Bergmann6e9624b2010-08-07 18:25:34 +02001983
Daniel Stodden13961742010-08-07 18:36:53 +02001984 info = disk->private_data;
1985 if (!info) {
1986 /* xbdev gone */
1987 err = -ERESTARTSYS;
1988 goto out;
1989 }
1990
1991 mutex_lock(&info->mutex);
1992
1993 if (!info->gd)
1994 /* xbdev is closed */
1995 err = -ERESTARTSYS;
1996
1997 mutex_unlock(&info->mutex);
1998
Daniel Stodden13961742010-08-07 18:36:53 +02001999out:
Arnd Bergmann2a48fc02010-06-02 14:28:52 +02002000 mutex_unlock(&blkfront_mutex);
Daniel Stodden13961742010-08-07 18:36:53 +02002001 return err;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002002}
2003
Al Virodb2a1442013-05-05 21:52:57 -04002004static void blkif_release(struct gendisk *disk, fmode_t mode)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002005{
Al Viroa63c8482008-03-02 10:23:47 -05002006 struct blkfront_info *info = disk->private_data;
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002007 struct block_device *bdev;
2008 struct xenbus_device *xbdev;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002009
Arnd Bergmann2a48fc02010-06-02 14:28:52 +02002010 mutex_lock(&blkfront_mutex);
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002011
2012 bdev = bdget_disk(disk, 0);
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002013
Felipe Pena2f089cb2013-11-09 13:36:09 -02002014 if (!bdev) {
2015 WARN(1, "Block device %s yanked out from us!\n", disk->disk_name);
2016 goto out_mutex;
2017 }
Daniel Stoddenacfca3c2010-08-07 18:47:26 +02002018 if (bdev->bd_openers)
2019 goto out;
2020
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002021 /*
2022 * Check if we have been instructed to close. We will have
2023 * deferred this request, because the bdev was still open.
2024 */
2025
2026 mutex_lock(&info->mutex);
2027 xbdev = info->xbdev;
2028
2029 if (xbdev && xbdev->state == XenbusStateClosing) {
2030 /* pending switch to state closed */
Daniel Stoddend54142c2010-08-07 18:51:21 +02002031 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002032 xlvbd_release_gendisk(info);
2033 xenbus_frontend_closed(info->xbdev);
2034 }
2035
2036 mutex_unlock(&info->mutex);
2037
2038 if (!xbdev) {
2039 /* sudden device removal */
Daniel Stoddend54142c2010-08-07 18:51:21 +02002040 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002041 xlvbd_release_gendisk(info);
2042 disk->private_data = NULL;
2043 kfree(info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002044 }
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002045
Jens Axboea4cc14e2010-08-08 21:50:05 -04002046out:
Andrew Jonesdad5cf62012-02-16 13:16:25 +01002047 bdput(bdev);
Felipe Pena2f089cb2013-11-09 13:36:09 -02002048out_mutex:
Arnd Bergmann2a48fc02010-06-02 14:28:52 +02002049 mutex_unlock(&blkfront_mutex);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002050}
2051
Alexey Dobriyan83d5cde2009-09-21 17:01:13 -07002052static const struct block_device_operations xlvbd_block_fops =
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002053{
2054 .owner = THIS_MODULE,
Al Viroa63c8482008-03-02 10:23:47 -05002055 .open = blkif_open,
2056 .release = blkif_release,
Ian Campbell597592d2008-02-21 13:03:45 -08002057 .getgeo = blkif_getgeo,
Arnd Bergmann8a6cfeb2010-07-08 10:18:46 +02002058 .ioctl = blkif_ioctl,
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002059};
2060
2061
Márton Némethec9c42e2010-01-10 13:39:52 +01002062static const struct xenbus_device_id blkfront_ids[] = {
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002063 { "vbd" },
2064 { "" }
2065};
2066
Jan Beulich73db1442011-12-22 09:08:13 +00002067static DEFINE_XENBUS_DRIVER(blkfront, ,
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002068 .probe = blkfront_probe,
2069 .remove = blkfront_remove,
2070 .resume = blkfront_resume,
Ian Campbell203fd612009-12-04 15:33:54 +00002071 .otherend_changed = blkback_changed,
Christian Limpach1d78d702008-04-02 10:54:04 -07002072 .is_ready = blkfront_is_ready,
Jan Beulich73db1442011-12-22 09:08:13 +00002073);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002074
2075static int __init xlblk_init(void)
2076{
Laszlo Ersek469738e2011-10-07 21:34:38 +02002077 int ret;
2078
Jeremy Fitzhardinge6e833582008-08-19 13:16:17 -07002079 if (!xen_domain())
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002080 return -ENODEV;
2081
Igor Mammedove95ae5a2012-03-27 19:31:08 +02002082 if (xen_hvm_domain() && !xen_platform_pci_unplug)
Igor Mammedovb9136d22012-03-21 15:08:38 +01002083 return -ENODEV;
2084
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002085 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
2086 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
2087 XENVBD_MAJOR, DEV_NAME);
2088 return -ENODEV;
2089 }
2090
Jan Beulich73db1442011-12-22 09:08:13 +00002091 ret = xenbus_register_frontend(&blkfront_driver);
Laszlo Ersek469738e2011-10-07 21:34:38 +02002092 if (ret) {
2093 unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
2094 return ret;
2095 }
2096
2097 return 0;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002098}
2099module_init(xlblk_init);
2100
2101
Jan Beulich5a60d0c2008-06-17 10:47:08 +02002102static void __exit xlblk_exit(void)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002103{
Jan Beulich86050672012-04-05 16:04:52 +01002104 xenbus_unregister_driver(&blkfront_driver);
2105 unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
2106 kfree(minors);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002107}
2108module_exit(xlblk_exit);
2109
2110MODULE_DESCRIPTION("Xen virtual block device frontend");
2111MODULE_LICENSE("GPL");
2112MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
Mark McLoughlind2f0c522008-04-02 10:54:05 -07002113MODULE_ALIAS("xen:vbd");
Mark McLoughlin4f93f09b2008-04-02 10:54:06 -07002114MODULE_ALIAS("xenblk");