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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>
Bob Liu907c3eb2015-07-13 17:55:24 +080040#include <linux/blk-mq.h>
Ian Campbell597592d2008-02-21 13:03:45 -080041#include <linux/hdreg.h>
Christian Limpach440a01a2008-06-17 10:47:08 +020042#include <linux/cdrom.h>
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070043#include <linux/module.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090044#include <linux/slab.h>
Arnd Bergmann2a48fc02010-06-02 14:28:52 +020045#include <linux/mutex.h>
Jens Axboe9e973e62009-02-24 08:10:09 +010046#include <linux/scatterlist.h>
Akinobu Mita34ae2e42012-01-21 00:15:26 +090047#include <linux/bitmap.h>
Roger Pau Monne155b7ed2013-03-18 17:49:34 +010048#include <linux/list.h>
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070049
Jeremy Fitzhardinge1ccbf532009-10-06 15:11:14 -070050#include <xen/xen.h>
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070051#include <xen/xenbus.h>
52#include <xen/grant_table.h>
53#include <xen/events.h>
54#include <xen/page.h>
Stefano Stabellinic1c54132010-05-14 12:44:30 +010055#include <xen/platform_pci.h>
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070056
57#include <xen/interface/grant_table.h>
58#include <xen/interface/io/blkif.h>
Markus Armbruster3e334232008-04-02 10:54:02 -070059#include <xen/interface/io/protocols.h>
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070060
61#include <asm/xen/hypervisor.h>
62
Julien Grall6cc568332015-08-13 13:13:35 +010063/*
64 * The minimal size of segment supported by the block framework is PAGE_SIZE.
65 * When Linux is using a different page size than Xen, it may not be possible
66 * to put all the data in a single segment.
67 * This can happen when the backend doesn't support indirect descriptor and
68 * therefore the maximum amount of data that a request can carry is
69 * BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE = 44KB
70 *
71 * Note that we only support one extra request. So the Linux page size
72 * should be <= ( 2 * BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE) =
73 * 88KB.
74 */
75#define HAS_EXTRA_REQ (BLKIF_MAX_SEGMENTS_PER_REQUEST < XEN_PFN_PER_PAGE)
76
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070077enum blkif_state {
78 BLKIF_STATE_DISCONNECTED,
79 BLKIF_STATE_CONNECTED,
80 BLKIF_STATE_SUSPENDED,
81};
82
Roger Pau Monne0a8704a2012-10-24 18:58:45 +020083struct grant {
84 grant_ref_t gref;
Julien Gralla7a6df22015-06-30 11:58:51 +010085 struct page *page;
Roger Pau Monne155b7ed2013-03-18 17:49:34 +010086 struct list_head node;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +020087};
88
Julien Grall6cc568332015-08-13 13:13:35 +010089enum blk_req_status {
90 REQ_WAITING,
91 REQ_DONE,
92 REQ_ERROR,
93 REQ_EOPNOTSUPP,
94};
95
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -070096struct blk_shadow {
97 struct blkif_request req;
Jeremy Fitzhardingea945b982010-11-01 17:03:14 -040098 struct request *request;
Roger Pau Monne402b27f2013-04-18 16:06:54 +020099 struct grant **grants_used;
100 struct grant **indirect_grants;
Roger Pau Monneb7649152013-05-02 10:58:50 +0200101 struct scatterlist *sg;
Julien Grallc004a6f2015-07-22 16:44:54 +0100102 unsigned int num_sg;
Julien Grall6cc568332015-08-13 13:13:35 +0100103 enum blk_req_status status;
104
105 #define NO_ASSOCIATED_ID ~0UL
106 /*
107 * Id of the sibling if we ever need 2 requests when handling a
108 * block I/O request
109 */
110 unsigned long associated_id;
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200111};
112
113struct split_bio {
114 struct bio *bio;
115 atomic_t pending;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700116};
117
Arnd Bergmann2a48fc02010-06-02 14:28:52 +0200118static DEFINE_MUTEX(blkfront_mutex);
Alexey Dobriyan83d5cde2009-09-21 17:01:13 -0700119static const struct block_device_operations xlvbd_block_fops;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700120
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200121/*
122 * Maximum number of segments in indirect requests, the actual value used by
123 * the frontend driver is the minimum of this value and the value provided
124 * by the backend driver.
125 */
126
127static unsigned int xen_blkif_max_segments = 32;
Jan Beulich14e710f2016-02-10 04:21:15 -0700128module_param_named(max_indirect_segments, xen_blkif_max_segments, uint,
129 S_IRUGO);
130MODULE_PARM_DESC(max_indirect_segments,
131 "Maximum amount of segments in indirect requests (default is 32)");
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200132
Bob Liu28d949b2015-11-14 11:12:14 +0800133static unsigned int xen_blkif_max_queues = 4;
134module_param_named(max_queues, xen_blkif_max_queues, uint, S_IRUGO);
135MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings used per virtual disk");
136
Bob Liu86839c52015-06-03 13:40:03 +0800137/*
138 * Maximum order of pages to be used for the shared ring between front and
139 * backend, 4KB page granularity is used.
140 */
141static unsigned int xen_blkif_max_ring_order;
142module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, S_IRUGO);
143MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring");
144
Julien Grallc004a6f2015-07-22 16:44:54 +0100145#define BLK_RING_SIZE(info) \
146 __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * (info)->nr_ring_pages)
147
148#define BLK_MAX_RING_SIZE \
Julien Grall9cce2912015-10-13 17:50:11 +0100149 __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * XENBUS_MAX_RING_GRANTS)
Julien Grallc004a6f2015-07-22 16:44:54 +0100150
Bob Liu86839c52015-06-03 13:40:03 +0800151/*
Konrad Rzeszutek Wilk6f03a7f2015-11-16 15:14:41 -0500152 * ring-ref%u i=(-1UL) would take 11 characters + 'ring-ref' is 8, so 19
153 * characters are enough. Define to 20 to keep consistent with backend.
Bob Liu86839c52015-06-03 13:40:03 +0800154 */
155#define RINGREF_NAME_LEN (20)
Bob Liu28d949b2015-11-14 11:12:14 +0800156/*
157 * queue-%u would take 7 + 10(UINT_MAX) = 17 characters.
158 */
159#define QUEUE_NAME_LEN (17)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700160
161/*
Bob Liu81f35162015-11-14 11:12:11 +0800162 * Per-ring info.
163 * Every blkfront device can associate with one or more blkfront_ring_info,
164 * depending on how many hardware queues/rings to be used.
165 */
166struct blkfront_ring_info {
Bob Liu11659562015-11-14 11:12:13 +0800167 /* Lock to protect data in every ring buffer. */
168 spinlock_t ring_lock;
Bob Liu81f35162015-11-14 11:12:11 +0800169 struct blkif_front_ring ring;
170 unsigned int ring_ref[XENBUS_MAX_RING_GRANTS];
171 unsigned int evtchn, irq;
172 struct work_struct work;
173 struct gnttab_free_callback callback;
174 struct blk_shadow shadow[BLK_MAX_RING_SIZE];
175 struct list_head indirect_pages;
Bob Liu73716df2015-11-16 16:51:39 -0500176 struct list_head grants;
177 unsigned int persistent_gnts_c;
Bob Liu81f35162015-11-14 11:12:11 +0800178 unsigned long shadow_free;
179 struct blkfront_info *dev_info;
180};
181
182/*
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700183 * We have one of these per vbd, whether ide, scsi or 'other'. They
184 * hang in private_data off the gendisk structure. We may end up
185 * putting all kinds of interesting stuff here :-)
186 */
187struct blkfront_info
188{
Daniel Stoddenb70f5fa2010-04-30 22:01:19 +0000189 struct mutex mutex;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700190 struct xenbus_device *xbdev;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700191 struct gendisk *gd;
192 int vdevice;
193 blkif_vdev_t handle;
194 enum blkif_state connected;
Bob Liu3df0e502015-11-14 11:12:12 +0800195 /* Number of pages per ring buffer. */
Bob Liu86839c52015-06-03 13:40:03 +0800196 unsigned int nr_ring_pages;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700197 struct request_queue *rq;
Tejun Heo4913efe2010-09-03 11:56:16 +0200198 unsigned int feature_flush;
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -0400199 unsigned int feature_discard:1;
200 unsigned int feature_secdiscard:1;
Li Dongyanged30bf32011-09-01 18:39:09 +0800201 unsigned int discard_granularity;
202 unsigned int discard_alignment;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200203 unsigned int feature_persistent:1;
Julien Grallc004a6f2015-07-22 16:44:54 +0100204 /* Number of 4KB segments handled */
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200205 unsigned int max_indirect_segments;
Christian Limpach1d78d702008-04-02 10:54:04 -0700206 int is_ready;
Bob Liu907c3eb2015-07-13 17:55:24 +0800207 struct blk_mq_tag_set tag_set;
Bob Liu3df0e502015-11-14 11:12:12 +0800208 struct blkfront_ring_info *rinfo;
209 unsigned int nr_rings;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700210};
211
Jan Beulich0e345822010-08-07 18:28:55 +0200212static unsigned int nr_minors;
213static unsigned long *minors;
214static DEFINE_SPINLOCK(minor_lock);
215
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700216#define GRANT_INVALID_REF 0
217
218#define PARTS_PER_DISK 16
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700219#define PARTS_PER_EXT_DISK 256
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700220
221#define BLKIF_MAJOR(dev) ((dev)>>8)
222#define BLKIF_MINOR(dev) ((dev) & 0xff)
223
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700224#define EXT_SHIFT 28
225#define EXTENDED (1<<EXT_SHIFT)
226#define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
227#define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
Stefano Stabellinic80a4202010-12-02 17:55:00 +0000228#define EMULATED_HD_DISK_MINOR_OFFSET (0)
229#define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256)
Stefan Bader196cfe22011-07-14 15:30:22 +0200230#define EMULATED_SD_DISK_MINOR_OFFSET (0)
231#define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700232
Chris Lalancette9246b5f2008-09-17 14:30:32 -0700233#define DEV_NAME "xvd" /* name in /dev */
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700234
Julien Grallc004a6f2015-07-22 16:44:54 +0100235/*
236 * Grants are always the same size as a Xen page (i.e 4KB).
237 * A physical segment is always the same size as a Linux page.
238 * Number of grants per physical segment
239 */
240#define GRANTS_PER_PSEG (PAGE_SIZE / XEN_PAGE_SIZE)
241
242#define GRANTS_PER_INDIRECT_FRAME \
243 (XEN_PAGE_SIZE / sizeof(struct blkif_request_segment))
244
245#define PSEGS_PER_INDIRECT_FRAME \
246 (GRANTS_INDIRECT_FRAME / GRANTS_PSEGS)
247
248#define INDIRECT_GREFS(_grants) \
249 DIV_ROUND_UP(_grants, GRANTS_PER_INDIRECT_FRAME)
250
251#define GREFS(_psegs) ((_psegs) * GRANTS_PER_PSEG)
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200252
Bob Liu81f35162015-11-14 11:12:11 +0800253static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo);
Bob Liu3df0e502015-11-14 11:12:12 +0800254static void blkfront_gather_backend_features(struct blkfront_info *info);
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200255
Bob Liu81f35162015-11-14 11:12:11 +0800256static int get_id_from_freelist(struct blkfront_ring_info *rinfo)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700257{
Bob Liu81f35162015-11-14 11:12:11 +0800258 unsigned long free = rinfo->shadow_free;
259
260 BUG_ON(free >= BLK_RING_SIZE(rinfo->dev_info));
261 rinfo->shadow_free = rinfo->shadow[free].req.u.rw.id;
262 rinfo->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700263 return free;
264}
265
Bob Liu81f35162015-11-14 11:12:11 +0800266static int add_id_to_freelist(struct blkfront_ring_info *rinfo,
Konrad Rzeszutek Wilk6f03a7f2015-11-16 15:14:41 -0500267 unsigned long id)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700268{
Bob Liu81f35162015-11-14 11:12:11 +0800269 if (rinfo->shadow[id].req.u.rw.id != id)
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -0400270 return -EINVAL;
Bob Liu81f35162015-11-14 11:12:11 +0800271 if (rinfo->shadow[id].request == NULL)
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -0400272 return -EINVAL;
Bob Liu81f35162015-11-14 11:12:11 +0800273 rinfo->shadow[id].req.u.rw.id = rinfo->shadow_free;
274 rinfo->shadow[id].request = NULL;
275 rinfo->shadow_free = id;
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -0400276 return 0;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700277}
278
Bob Liu81f35162015-11-14 11:12:11 +0800279static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num)
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100280{
Bob Liu81f35162015-11-14 11:12:11 +0800281 struct blkfront_info *info = rinfo->dev_info;
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100282 struct page *granted_page;
283 struct grant *gnt_list_entry, *n;
284 int i = 0;
285
Konrad Rzeszutek Wilk6f03a7f2015-11-16 15:14:41 -0500286 while (i < num) {
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100287 gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO);
288 if (!gnt_list_entry)
289 goto out_of_memory;
290
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100291 if (info->feature_persistent) {
292 granted_page = alloc_page(GFP_NOIO);
293 if (!granted_page) {
294 kfree(gnt_list_entry);
295 goto out_of_memory;
296 }
Julien Gralla7a6df22015-06-30 11:58:51 +0100297 gnt_list_entry->page = granted_page;
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100298 }
299
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100300 gnt_list_entry->gref = GRANT_INVALID_REF;
Bob Liu73716df2015-11-16 16:51:39 -0500301 list_add(&gnt_list_entry->node, &rinfo->grants);
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100302 i++;
303 }
304
305 return 0;
306
307out_of_memory:
308 list_for_each_entry_safe(gnt_list_entry, n,
Bob Liu73716df2015-11-16 16:51:39 -0500309 &rinfo->grants, node) {
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100310 list_del(&gnt_list_entry->node);
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100311 if (info->feature_persistent)
Julien Gralla7a6df22015-06-30 11:58:51 +0100312 __free_page(gnt_list_entry->page);
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100313 kfree(gnt_list_entry);
314 i--;
315 }
316 BUG_ON(i != 0);
317 return -ENOMEM;
318}
319
Bob Liu73716df2015-11-16 16:51:39 -0500320static struct grant *get_free_grant(struct blkfront_ring_info *rinfo)
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100321{
322 struct grant *gnt_list_entry;
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100323
Bob Liu73716df2015-11-16 16:51:39 -0500324 BUG_ON(list_empty(&rinfo->grants));
325 gnt_list_entry = list_first_entry(&rinfo->grants, struct grant,
Julien Grall4f503fb2015-07-01 14:10:38 +0100326 node);
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100327 list_del(&gnt_list_entry->node);
328
Julien Grall4f503fb2015-07-01 14:10:38 +0100329 if (gnt_list_entry->gref != GRANT_INVALID_REF)
Bob Liu73716df2015-11-16 16:51:39 -0500330 rinfo->persistent_gnts_c--;
Julien Grall4f503fb2015-07-01 14:10:38 +0100331
332 return gnt_list_entry;
333}
334
335static inline void grant_foreign_access(const struct grant *gnt_list_entry,
336 const struct blkfront_info *info)
337{
338 gnttab_page_grant_foreign_access_ref_one(gnt_list_entry->gref,
339 info->xbdev->otherend_id,
340 gnt_list_entry->page,
341 0);
342}
343
344static struct grant *get_grant(grant_ref_t *gref_head,
345 unsigned long gfn,
Bob Liu73716df2015-11-16 16:51:39 -0500346 struct blkfront_ring_info *rinfo)
Julien Grall4f503fb2015-07-01 14:10:38 +0100347{
Bob Liu73716df2015-11-16 16:51:39 -0500348 struct grant *gnt_list_entry = get_free_grant(rinfo);
349 struct blkfront_info *info = rinfo->dev_info;
Julien Grall4f503fb2015-07-01 14:10:38 +0100350
351 if (gnt_list_entry->gref != GRANT_INVALID_REF)
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100352 return gnt_list_entry;
Julien Grall4f503fb2015-07-01 14:10:38 +0100353
354 /* Assign a gref to this page */
355 gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
356 BUG_ON(gnt_list_entry->gref == -ENOSPC);
357 if (info->feature_persistent)
358 grant_foreign_access(gnt_list_entry, info);
359 else {
360 /* Grant access to the GFN passed by the caller */
361 gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
362 info->xbdev->otherend_id,
363 gfn, 0);
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100364 }
365
Julien Grall4f503fb2015-07-01 14:10:38 +0100366 return gnt_list_entry;
367}
368
369static struct grant *get_indirect_grant(grant_ref_t *gref_head,
Bob Liu73716df2015-11-16 16:51:39 -0500370 struct blkfront_ring_info *rinfo)
Julien Grall4f503fb2015-07-01 14:10:38 +0100371{
Bob Liu73716df2015-11-16 16:51:39 -0500372 struct grant *gnt_list_entry = get_free_grant(rinfo);
373 struct blkfront_info *info = rinfo->dev_info;
Julien Grall4f503fb2015-07-01 14:10:38 +0100374
375 if (gnt_list_entry->gref != GRANT_INVALID_REF)
376 return gnt_list_entry;
377
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100378 /* Assign a gref to this page */
379 gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
380 BUG_ON(gnt_list_entry->gref == -ENOSPC);
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100381 if (!info->feature_persistent) {
Julien Grall4f503fb2015-07-01 14:10:38 +0100382 struct page *indirect_page;
383
384 /* Fetch a pre-allocated page to use for indirect grefs */
Bob Liu73716df2015-11-16 16:51:39 -0500385 BUG_ON(list_empty(&rinfo->indirect_pages));
386 indirect_page = list_first_entry(&rinfo->indirect_pages,
Julien Grall4f503fb2015-07-01 14:10:38 +0100387 struct page, lru);
388 list_del(&indirect_page->lru);
389 gnt_list_entry->page = indirect_page;
Roger Pau Monnebfe11d62013-10-29 18:31:14 +0100390 }
Julien Grall4f503fb2015-07-01 14:10:38 +0100391 grant_foreign_access(gnt_list_entry, info);
392
Roger Pau Monne9c1e0502013-03-18 17:49:35 +0100393 return gnt_list_entry;
394}
395
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -0400396static const char *op_name(int op)
397{
398 static const char *const names[] = {
399 [BLKIF_OP_READ] = "read",
400 [BLKIF_OP_WRITE] = "write",
401 [BLKIF_OP_WRITE_BARRIER] = "barrier",
402 [BLKIF_OP_FLUSH_DISKCACHE] = "flush",
403 [BLKIF_OP_DISCARD] = "discard" };
404
405 if (op < 0 || op >= ARRAY_SIZE(names))
406 return "unknown";
407
408 if (!names[op])
409 return "reserved";
410
411 return names[op];
412}
Jan Beulich0e345822010-08-07 18:28:55 +0200413static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
414{
415 unsigned int end = minor + nr;
416 int rc;
417
418 if (end > nr_minors) {
419 unsigned long *bitmap, *old;
420
Thomas Meyerf0941482011-11-29 22:08:00 +0100421 bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap),
Jan Beulich0e345822010-08-07 18:28:55 +0200422 GFP_KERNEL);
423 if (bitmap == NULL)
424 return -ENOMEM;
425
426 spin_lock(&minor_lock);
427 if (end > nr_minors) {
428 old = minors;
429 memcpy(bitmap, minors,
430 BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
431 minors = bitmap;
432 nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
433 } else
434 old = bitmap;
435 spin_unlock(&minor_lock);
436 kfree(old);
437 }
438
439 spin_lock(&minor_lock);
440 if (find_next_bit(minors, end, minor) >= end) {
Akinobu Mita34ae2e42012-01-21 00:15:26 +0900441 bitmap_set(minors, minor, nr);
Jan Beulich0e345822010-08-07 18:28:55 +0200442 rc = 0;
443 } else
444 rc = -EBUSY;
445 spin_unlock(&minor_lock);
446
447 return rc;
448}
449
450static void xlbd_release_minors(unsigned int minor, unsigned int nr)
451{
452 unsigned int end = minor + nr;
453
454 BUG_ON(end > nr_minors);
455 spin_lock(&minor_lock);
Akinobu Mita34ae2e42012-01-21 00:15:26 +0900456 bitmap_clear(minors, minor, nr);
Jan Beulich0e345822010-08-07 18:28:55 +0200457 spin_unlock(&minor_lock);
458}
459
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700460static void blkif_restart_queue_callback(void *arg)
461{
Bob Liu81f35162015-11-14 11:12:11 +0800462 struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)arg;
463 schedule_work(&rinfo->work);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700464}
465
Harvey Harrisonafe42d72008-04-29 00:59:47 -0700466static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
Ian Campbell597592d2008-02-21 13:03:45 -0800467{
468 /* We don't have real geometry info, but let's at least return
469 values consistent with the size of the device */
470 sector_t nsect = get_capacity(bd->bd_disk);
471 sector_t cylinders = nsect;
472
473 hg->heads = 0xff;
474 hg->sectors = 0x3f;
475 sector_div(cylinders, hg->heads * hg->sectors);
476 hg->cylinders = cylinders;
477 if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
478 hg->cylinders = 0xffff;
479 return 0;
480}
481
Al Viroa63c8482008-03-02 10:23:47 -0500482static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
Adrian Bunk62aa0052008-08-04 11:59:05 +0200483 unsigned command, unsigned long argument)
Christian Limpach440a01a2008-06-17 10:47:08 +0200484{
Al Viroa63c8482008-03-02 10:23:47 -0500485 struct blkfront_info *info = bdev->bd_disk->private_data;
Christian Limpach440a01a2008-06-17 10:47:08 +0200486 int i;
487
488 dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
489 command, (long)argument);
490
491 switch (command) {
492 case CDROMMULTISESSION:
493 dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
494 for (i = 0; i < sizeof(struct cdrom_multisession); i++)
495 if (put_user(0, (char __user *)(argument + i)))
496 return -EFAULT;
497 return 0;
498
499 case CDROM_GET_CAPABILITY: {
500 struct gendisk *gd = info->gd;
501 if (gd->flags & GENHD_FL_CD)
502 return 0;
503 return -EINVAL;
504 }
505
506 default:
507 /*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
508 command);*/
509 return -EINVAL; /* same return as native Linux */
510 }
511
512 return 0;
513}
514
Julien Grall2e073962015-08-13 19:23:10 +0100515static unsigned long blkif_ring_get_request(struct blkfront_ring_info *rinfo,
516 struct request *req,
517 struct blkif_request **ring_req)
518{
519 unsigned long id;
520
521 *ring_req = RING_GET_REQUEST(&rinfo->ring, rinfo->ring.req_prod_pvt);
522 rinfo->ring.req_prod_pvt++;
523
524 id = get_id_from_freelist(rinfo);
525 rinfo->shadow[id].request = req;
Julien Grall6cc568332015-08-13 13:13:35 +0100526 rinfo->shadow[id].status = REQ_WAITING;
527 rinfo->shadow[id].associated_id = NO_ASSOCIATED_ID;
Julien Grall2e073962015-08-13 19:23:10 +0100528
529 (*ring_req)->u.rw.id = id;
530
531 return id;
532}
533
Bob Liu81f35162015-11-14 11:12:11 +0800534static int blkif_queue_discard_req(struct request *req, struct blkfront_ring_info *rinfo)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700535{
Bob Liu81f35162015-11-14 11:12:11 +0800536 struct blkfront_info *info = rinfo->dev_info;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700537 struct blkif_request *ring_req;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700538 unsigned long id;
Julien Grall33204662015-06-29 17:35:24 +0100539
540 /* Fill out a communications ring structure. */
Julien Grall2e073962015-08-13 19:23:10 +0100541 id = blkif_ring_get_request(rinfo, req, &ring_req);
Julien Grall33204662015-06-29 17:35:24 +0100542
543 ring_req->operation = BLKIF_OP_DISCARD;
544 ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
545 ring_req->u.discard.id = id;
546 ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req);
547 if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard)
548 ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;
549 else
550 ring_req->u.discard.flag = 0;
551
Julien Grall33204662015-06-29 17:35:24 +0100552 /* Keep a private copy so we can reissue requests when recovering. */
Bob Liu81f35162015-11-14 11:12:11 +0800553 rinfo->shadow[id].req = *ring_req;
Julien Grall33204662015-06-29 17:35:24 +0100554
555 return 0;
556}
557
Julien Grallc004a6f2015-07-22 16:44:54 +0100558struct setup_rw_req {
559 unsigned int grant_idx;
560 struct blkif_request_segment *segments;
Bob Liu81f35162015-11-14 11:12:11 +0800561 struct blkfront_ring_info *rinfo;
Julien Grallc004a6f2015-07-22 16:44:54 +0100562 struct blkif_request *ring_req;
563 grant_ref_t gref_head;
564 unsigned int id;
565 /* Only used when persistent grant is used and it's a read request */
566 bool need_copy;
567 unsigned int bvec_off;
568 char *bvec_data;
Julien Grall6cc568332015-08-13 13:13:35 +0100569
570 bool require_extra_req;
571 struct blkif_request *extra_ring_req;
Julien Grallc004a6f2015-07-22 16:44:54 +0100572};
573
574static void blkif_setup_rw_req_grant(unsigned long gfn, unsigned int offset,
575 unsigned int len, void *data)
576{
577 struct setup_rw_req *setup = data;
578 int n, ref;
579 struct grant *gnt_list_entry;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700580 unsigned int fsect, lsect;
Julien Grallc004a6f2015-07-22 16:44:54 +0100581 /* Convenient aliases */
582 unsigned int grant_idx = setup->grant_idx;
583 struct blkif_request *ring_req = setup->ring_req;
Bob Liu81f35162015-11-14 11:12:11 +0800584 struct blkfront_ring_info *rinfo = setup->rinfo;
Julien Grall6cc568332015-08-13 13:13:35 +0100585 /*
586 * We always use the shadow of the first request to store the list
587 * of grant associated to the block I/O request. This made the
588 * completion more easy to handle even if the block I/O request is
589 * split.
590 */
Bob Liu81f35162015-11-14 11:12:11 +0800591 struct blk_shadow *shadow = &rinfo->shadow[setup->id];
Julien Grallc004a6f2015-07-22 16:44:54 +0100592
Julien Grall6cc568332015-08-13 13:13:35 +0100593 if (unlikely(setup->require_extra_req &&
594 grant_idx >= BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
595 /*
596 * We are using the second request, setup grant_idx
597 * to be the index of the segment array.
598 */
599 grant_idx -= BLKIF_MAX_SEGMENTS_PER_REQUEST;
600 ring_req = setup->extra_ring_req;
601 }
602
Julien Grallc004a6f2015-07-22 16:44:54 +0100603 if ((ring_req->operation == BLKIF_OP_INDIRECT) &&
604 (grant_idx % GRANTS_PER_INDIRECT_FRAME == 0)) {
605 if (setup->segments)
606 kunmap_atomic(setup->segments);
607
608 n = grant_idx / GRANTS_PER_INDIRECT_FRAME;
Bob Liu73716df2015-11-16 16:51:39 -0500609 gnt_list_entry = get_indirect_grant(&setup->gref_head, rinfo);
Julien Grallc004a6f2015-07-22 16:44:54 +0100610 shadow->indirect_grants[n] = gnt_list_entry;
611 setup->segments = kmap_atomic(gnt_list_entry->page);
612 ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref;
613 }
614
Bob Liu73716df2015-11-16 16:51:39 -0500615 gnt_list_entry = get_grant(&setup->gref_head, gfn, rinfo);
Julien Grallc004a6f2015-07-22 16:44:54 +0100616 ref = gnt_list_entry->gref;
Julien Grall6cc568332015-08-13 13:13:35 +0100617 /*
618 * All the grants are stored in the shadow of the first
619 * request. Therefore we have to use the global index.
620 */
621 shadow->grants_used[setup->grant_idx] = gnt_list_entry;
Julien Grallc004a6f2015-07-22 16:44:54 +0100622
623 if (setup->need_copy) {
624 void *shared_data;
625
626 shared_data = kmap_atomic(gnt_list_entry->page);
627 /*
628 * this does not wipe data stored outside the
629 * range sg->offset..sg->offset+sg->length.
630 * Therefore, blkback *could* see data from
631 * previous requests. This is OK as long as
632 * persistent grants are shared with just one
633 * domain. It may need refactoring if this
634 * changes
635 */
636 memcpy(shared_data + offset,
637 setup->bvec_data + setup->bvec_off,
638 len);
639
640 kunmap_atomic(shared_data);
641 setup->bvec_off += len;
642 }
643
644 fsect = offset >> 9;
645 lsect = fsect + (len >> 9) - 1;
646 if (ring_req->operation != BLKIF_OP_INDIRECT) {
647 ring_req->u.rw.seg[grant_idx] =
648 (struct blkif_request_segment) {
649 .gref = ref,
650 .first_sect = fsect,
651 .last_sect = lsect };
652 } else {
653 setup->segments[grant_idx % GRANTS_PER_INDIRECT_FRAME] =
654 (struct blkif_request_segment) {
655 .gref = ref,
656 .first_sect = fsect,
657 .last_sect = lsect };
658 }
659
660 (setup->grant_idx)++;
661}
662
Julien Grall6cc568332015-08-13 13:13:35 +0100663static void blkif_setup_extra_req(struct blkif_request *first,
664 struct blkif_request *second)
665{
666 uint16_t nr_segments = first->u.rw.nr_segments;
667
668 /*
669 * The second request is only present when the first request uses
670 * all its segments. It's always the continuity of the first one.
671 */
672 first->u.rw.nr_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST;
673
674 second->u.rw.nr_segments = nr_segments - BLKIF_MAX_SEGMENTS_PER_REQUEST;
675 second->u.rw.sector_number = first->u.rw.sector_number +
676 (BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE) / 512;
677
678 second->u.rw.handle = first->u.rw.handle;
679 second->operation = first->operation;
680}
681
Bob Liu81f35162015-11-14 11:12:11 +0800682static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *rinfo)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700683{
Bob Liu81f35162015-11-14 11:12:11 +0800684 struct blkfront_info *info = rinfo->dev_info;
Julien Grall6cc568332015-08-13 13:13:35 +0100685 struct blkif_request *ring_req, *extra_ring_req = NULL;
686 unsigned long id, extra_id = NO_ASSOCIATED_ID;
687 bool require_extra_req = false;
Julien Grallc004a6f2015-07-22 16:44:54 +0100688 int i;
689 struct setup_rw_req setup = {
690 .grant_idx = 0,
691 .segments = NULL,
Bob Liu81f35162015-11-14 11:12:11 +0800692 .rinfo = rinfo,
Julien Grallc004a6f2015-07-22 16:44:54 +0100693 .need_copy = rq_data_dir(req) && info->feature_persistent,
694 };
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200695
696 /*
697 * Used to store if we are able to queue the request by just using
698 * existing persistent grants, or if we have to get new grants,
699 * as there are not sufficiently many free.
700 */
Jens Axboe9e973e62009-02-24 08:10:09 +0100701 struct scatterlist *sg;
Julien Grallc004a6f2015-07-22 16:44:54 +0100702 int num_sg, max_grefs, num_grant;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700703
Julien Grallc004a6f2015-07-22 16:44:54 +0100704 max_grefs = req->nr_phys_segments * GRANTS_PER_PSEG;
Roger Pau Monnec47206e2013-08-12 12:53:43 +0200705 if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST)
706 /*
707 * If we are using indirect segments we need to account
708 * for the indirect grefs used in the request.
709 */
Julien Grallc004a6f2015-07-22 16:44:54 +0100710 max_grefs += INDIRECT_GREFS(max_grefs);
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200711
Bob Liu3df0e502015-11-14 11:12:12 +0800712 /*
713 * We have to reserve 'max_grefs' grants because persistent
714 * grants are shared by all rings.
715 */
716 if (max_grefs > 0)
717 if (gnttab_alloc_grant_references(max_grefs, &setup.gref_head) < 0) {
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200718 gnttab_request_free_callback(
Bob Liu81f35162015-11-14 11:12:11 +0800719 &rinfo->callback,
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200720 blkif_restart_queue_callback,
Bob Liu81f35162015-11-14 11:12:11 +0800721 rinfo,
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200722 max_grefs);
Roger Pau Monne0a8704a2012-10-24 18:58:45 +0200723 return 1;
724 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700725
726 /* Fill out a communications ring structure. */
Julien Grall2e073962015-08-13 19:23:10 +0100727 id = blkif_ring_get_request(rinfo, req, &ring_req);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700728
Bob Liu81f35162015-11-14 11:12:11 +0800729 num_sg = blk_rq_map_sg(req->q, req, rinfo->shadow[id].sg);
Julien Grallc004a6f2015-07-22 16:44:54 +0100730 num_grant = 0;
731 /* Calculate the number of grant used */
Bob Liu81f35162015-11-14 11:12:11 +0800732 for_each_sg(rinfo->shadow[id].sg, sg, num_sg, i)
Julien Grallc004a6f2015-07-22 16:44:54 +0100733 num_grant += gnttab_count_grant(sg->offset, sg->length);
734
Julien Grall6cc568332015-08-13 13:13:35 +0100735 require_extra_req = info->max_indirect_segments == 0 &&
736 num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST;
737 BUG_ON(!HAS_EXTRA_REQ && require_extra_req);
738
Bob Liu81f35162015-11-14 11:12:11 +0800739 rinfo->shadow[id].num_sg = num_sg;
Julien Grall6cc568332015-08-13 13:13:35 +0100740 if (num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST &&
741 likely(!require_extra_req)) {
Julien Grall33204662015-06-29 17:35:24 +0100742 /*
743 * The indirect operation can only be a BLKIF_OP_READ or
744 * BLKIF_OP_WRITE
745 */
746 BUG_ON(req->cmd_flags & (REQ_FLUSH | REQ_FUA));
747 ring_req->operation = BLKIF_OP_INDIRECT;
748 ring_req->u.indirect.indirect_op = rq_data_dir(req) ?
749 BLKIF_OP_WRITE : BLKIF_OP_READ;
750 ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req);
751 ring_req->u.indirect.handle = info->handle;
Julien Grallc004a6f2015-07-22 16:44:54 +0100752 ring_req->u.indirect.nr_segments = num_grant;
Li Dongyanged30bf32011-09-01 18:39:09 +0800753 } else {
Julien Grall33204662015-06-29 17:35:24 +0100754 ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req);
755 ring_req->u.rw.handle = info->handle;
756 ring_req->operation = rq_data_dir(req) ?
757 BLKIF_OP_WRITE : BLKIF_OP_READ;
758 if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200759 /*
Julien Grall33204662015-06-29 17:35:24 +0100760 * Ideally we can do an unordered flush-to-disk.
761 * In case the backend onlysupports barriers, use that.
762 * A barrier request a superset of FUA, so we can
763 * implement it the same way. (It's also a FLUSH+FUA,
764 * since it is guaranteed ordered WRT previous writes.)
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200765 */
Julien Grall33204662015-06-29 17:35:24 +0100766 switch (info->feature_flush &
767 ((REQ_FLUSH|REQ_FUA))) {
768 case REQ_FLUSH|REQ_FUA:
769 ring_req->operation =
770 BLKIF_OP_WRITE_BARRIER;
771 break;
772 case REQ_FLUSH:
773 ring_req->operation =
774 BLKIF_OP_FLUSH_DISKCACHE;
775 break;
776 default:
777 ring_req->operation = 0;
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200778 }
Li Dongyanged30bf32011-09-01 18:39:09 +0800779 }
Julien Grallc004a6f2015-07-22 16:44:54 +0100780 ring_req->u.rw.nr_segments = num_grant;
Julien Grall6cc568332015-08-13 13:13:35 +0100781 if (unlikely(require_extra_req)) {
782 extra_id = blkif_ring_get_request(rinfo, req,
783 &extra_ring_req);
784 /*
785 * Only the first request contains the scatter-gather
786 * list.
787 */
788 rinfo->shadow[extra_id].num_sg = 0;
789
790 blkif_setup_extra_req(ring_req, extra_ring_req);
791
792 /* Link the 2 requests together */
793 rinfo->shadow[extra_id].associated_id = id;
794 rinfo->shadow[id].associated_id = extra_id;
795 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700796 }
797
Julien Grallc004a6f2015-07-22 16:44:54 +0100798 setup.ring_req = ring_req;
799 setup.id = id;
Julien Grall6cc568332015-08-13 13:13:35 +0100800
801 setup.require_extra_req = require_extra_req;
802 if (unlikely(require_extra_req))
803 setup.extra_ring_req = extra_ring_req;
804
Bob Liu81f35162015-11-14 11:12:11 +0800805 for_each_sg(rinfo->shadow[id].sg, sg, num_sg, i) {
Julien Grallc004a6f2015-07-22 16:44:54 +0100806 BUG_ON(sg->offset + sg->length > PAGE_SIZE);
Julien Grall33204662015-06-29 17:35:24 +0100807
Julien Grallc004a6f2015-07-22 16:44:54 +0100808 if (setup.need_copy) {
809 setup.bvec_off = sg->offset;
810 setup.bvec_data = kmap_atomic(sg_page(sg));
Julien Grall33204662015-06-29 17:35:24 +0100811 }
812
Julien Grallc004a6f2015-07-22 16:44:54 +0100813 gnttab_foreach_grant_in_range(sg_page(sg),
814 sg->offset,
815 sg->length,
816 blkif_setup_rw_req_grant,
817 &setup);
Julien Grall33204662015-06-29 17:35:24 +0100818
Julien Grallc004a6f2015-07-22 16:44:54 +0100819 if (setup.need_copy)
820 kunmap_atomic(setup.bvec_data);
Julien Grall33204662015-06-29 17:35:24 +0100821 }
Julien Grallc004a6f2015-07-22 16:44:54 +0100822 if (setup.segments)
823 kunmap_atomic(setup.segments);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700824
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700825 /* Keep a private copy so we can reissue requests when recovering. */
Bob Liu81f35162015-11-14 11:12:11 +0800826 rinfo->shadow[id].req = *ring_req;
Julien Grall6cc568332015-08-13 13:13:35 +0100827 if (unlikely(require_extra_req))
828 rinfo->shadow[extra_id].req = *extra_ring_req;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700829
Bob Liu3df0e502015-11-14 11:12:12 +0800830 if (max_grefs > 0)
Julien Grallc004a6f2015-07-22 16:44:54 +0100831 gnttab_free_grant_references(setup.gref_head);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700832
833 return 0;
834}
835
Julien Grall33204662015-06-29 17:35:24 +0100836/*
837 * Generate a Xen blkfront IO request from a blk layer request. Reads
838 * and writes are handled as expected.
839 *
840 * @req: a request struct
841 */
Bob Liu81f35162015-11-14 11:12:11 +0800842static int blkif_queue_request(struct request *req, struct blkfront_ring_info *rinfo)
Julien Grall33204662015-06-29 17:35:24 +0100843{
Bob Liu81f35162015-11-14 11:12:11 +0800844 if (unlikely(rinfo->dev_info->connected != BLKIF_STATE_CONNECTED))
Julien Grall33204662015-06-29 17:35:24 +0100845 return 1;
846
847 if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE)))
Bob Liu81f35162015-11-14 11:12:11 +0800848 return blkif_queue_discard_req(req, rinfo);
Julien Grall33204662015-06-29 17:35:24 +0100849 else
Bob Liu81f35162015-11-14 11:12:11 +0800850 return blkif_queue_rw_req(req, rinfo);
Julien Grall33204662015-06-29 17:35:24 +0100851}
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700852
Bob Liu81f35162015-11-14 11:12:11 +0800853static inline void flush_requests(struct blkfront_ring_info *rinfo)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700854{
855 int notify;
856
Bob Liu81f35162015-11-14 11:12:11 +0800857 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&rinfo->ring, notify);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700858
859 if (notify)
Bob Liu81f35162015-11-14 11:12:11 +0800860 notify_remote_via_irq(rinfo->irq);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700861}
862
Vitaly Kuznetsovad42d392014-12-01 14:01:13 +0100863static inline bool blkif_request_flush_invalid(struct request *req,
864 struct blkfront_info *info)
Arianna Avanzini0f1ca652014-08-22 13:20:02 +0200865{
866 return ((req->cmd_type != REQ_TYPE_FS) ||
Vitaly Kuznetsovad42d392014-12-01 14:01:13 +0100867 ((req->cmd_flags & REQ_FLUSH) &&
868 !(info->feature_flush & REQ_FLUSH)) ||
869 ((req->cmd_flags & REQ_FUA) &&
870 !(info->feature_flush & REQ_FUA)));
Arianna Avanzini0f1ca652014-08-22 13:20:02 +0200871}
872
Bob Liu907c3eb2015-07-13 17:55:24 +0800873static int blkif_queue_rq(struct blk_mq_hw_ctx *hctx,
Konrad Rzeszutek Wilk6f03a7f2015-11-16 15:14:41 -0500874 const struct blk_mq_queue_data *qd)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700875{
Bob Liu11659562015-11-14 11:12:13 +0800876 unsigned long flags;
Bob Liu2a6f71a2016-05-31 16:59:17 +0800877 int qid = hctx->queue_num;
878 struct blkfront_info *info = hctx->queue->queuedata;
879 struct blkfront_ring_info *rinfo = NULL;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700880
Bob Liu2a6f71a2016-05-31 16:59:17 +0800881 BUG_ON(info->nr_rings <= qid);
882 rinfo = &info->rinfo[qid];
Bob Liu907c3eb2015-07-13 17:55:24 +0800883 blk_mq_start_request(qd->rq);
Bob Liu11659562015-11-14 11:12:13 +0800884 spin_lock_irqsave(&rinfo->ring_lock, flags);
Bob Liu81f35162015-11-14 11:12:11 +0800885 if (RING_FULL(&rinfo->ring))
Bob Liu907c3eb2015-07-13 17:55:24 +0800886 goto out_busy;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700887
Bob Liu81f35162015-11-14 11:12:11 +0800888 if (blkif_request_flush_invalid(qd->rq, rinfo->dev_info))
Bob Liu907c3eb2015-07-13 17:55:24 +0800889 goto out_err;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700890
Bob Liu81f35162015-11-14 11:12:11 +0800891 if (blkif_queue_request(qd->rq, rinfo))
Bob Liu907c3eb2015-07-13 17:55:24 +0800892 goto out_busy;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700893
Bob Liu81f35162015-11-14 11:12:11 +0800894 flush_requests(rinfo);
Bob Liu11659562015-11-14 11:12:13 +0800895 spin_unlock_irqrestore(&rinfo->ring_lock, flags);
Bob Liu907c3eb2015-07-13 17:55:24 +0800896 return BLK_MQ_RQ_QUEUE_OK;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700897
Bob Liu907c3eb2015-07-13 17:55:24 +0800898out_err:
Bob Liu11659562015-11-14 11:12:13 +0800899 spin_unlock_irqrestore(&rinfo->ring_lock, flags);
Bob Liu907c3eb2015-07-13 17:55:24 +0800900 return BLK_MQ_RQ_QUEUE_ERROR;
Tejun Heo296b2f62009-05-08 11:54:15 +0900901
Bob Liu907c3eb2015-07-13 17:55:24 +0800902out_busy:
Bob Liu11659562015-11-14 11:12:13 +0800903 spin_unlock_irqrestore(&rinfo->ring_lock, flags);
Bob Liu907c3eb2015-07-13 17:55:24 +0800904 blk_mq_stop_hw_queue(hctx);
905 return BLK_MQ_RQ_QUEUE_BUSY;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700906}
907
Bob Liu907c3eb2015-07-13 17:55:24 +0800908static struct blk_mq_ops blkfront_mq_ops = {
909 .queue_rq = blkif_queue_rq,
910 .map_queue = blk_mq_map_queue,
911};
912
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200913static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
Stefan Bader7c4d7d72013-05-13 16:28:15 +0200914 unsigned int physical_sector_size,
Roger Pau Monne402b27f2013-04-18 16:06:54 +0200915 unsigned int segments)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700916{
Jens Axboe165125e2007-07-24 09:28:11 +0200917 struct request_queue *rq;
Li Dongyanged30bf32011-09-01 18:39:09 +0800918 struct blkfront_info *info = gd->private_data;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700919
Bob Liu907c3eb2015-07-13 17:55:24 +0800920 memset(&info->tag_set, 0, sizeof(info->tag_set));
921 info->tag_set.ops = &blkfront_mq_ops;
Bob Liu28d949b2015-11-14 11:12:14 +0800922 info->tag_set.nr_hw_queues = info->nr_rings;
Julien Grall6cc568332015-08-13 13:13:35 +0100923 if (HAS_EXTRA_REQ && info->max_indirect_segments == 0) {
924 /*
925 * When indirect descriptior is not supported, the I/O request
926 * will be split between multiple request in the ring.
927 * To avoid problems when sending the request, divide by
928 * 2 the depth of the queue.
929 */
930 info->tag_set.queue_depth = BLK_RING_SIZE(info) / 2;
931 } else
932 info->tag_set.queue_depth = BLK_RING_SIZE(info);
Bob Liu907c3eb2015-07-13 17:55:24 +0800933 info->tag_set.numa_node = NUMA_NO_NODE;
934 info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
935 info->tag_set.cmd_size = 0;
936 info->tag_set.driver_data = info;
937
938 if (blk_mq_alloc_tag_set(&info->tag_set))
Konrad Rzeszutek Wilkbde21f72015-11-25 13:07:39 -0500939 return -EINVAL;
Bob Liu907c3eb2015-07-13 17:55:24 +0800940 rq = blk_mq_init_queue(&info->tag_set);
941 if (IS_ERR(rq)) {
942 blk_mq_free_tag_set(&info->tag_set);
Konrad Rzeszutek Wilkbde21f72015-11-25 13:07:39 -0500943 return PTR_ERR(rq);
Bob Liu907c3eb2015-07-13 17:55:24 +0800944 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700945
Bob Liu2a6f71a2016-05-31 16:59:17 +0800946 rq->queuedata = info;
Fernando Luis Vázquez Cao66d352e2008-10-27 18:45:54 +0900947 queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700948
Li Dongyanged30bf32011-09-01 18:39:09 +0800949 if (info->feature_discard) {
950 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
951 blk_queue_max_discard_sectors(rq, get_capacity(gd));
952 rq->limits.discard_granularity = info->discard_granularity;
953 rq->limits.discard_alignment = info->discard_alignment;
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -0400954 if (info->feature_secdiscard)
955 queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, rq);
Li Dongyanged30bf32011-09-01 18:39:09 +0800956 }
957
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700958 /* Hard sector size and max sectors impersonate the equiv. hardware. */
Martin K. Petersene1defc42009-05-22 17:17:49 -0400959 blk_queue_logical_block_size(rq, sector_size);
Stefan Bader7c4d7d72013-05-13 16:28:15 +0200960 blk_queue_physical_block_size(rq, physical_sector_size);
Julien Grallc004a6f2015-07-22 16:44:54 +0100961 blk_queue_max_hw_sectors(rq, (segments * XEN_PAGE_SIZE) / 512);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700962
963 /* Each segment in a request is up to an aligned page in size. */
964 blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
965 blk_queue_max_segment_size(rq, PAGE_SIZE);
966
967 /* Ensure a merged request will fit in a single I/O ring slot. */
Julien Grallc004a6f2015-07-22 16:44:54 +0100968 blk_queue_max_segments(rq, segments / GRANTS_PER_PSEG);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700969
970 /* Make sure buffer addresses are sector-aligned. */
971 blk_queue_dma_alignment(rq, 511);
972
Ian Campbell1c91fe12008-06-17 10:47:08 +0200973 /* Make sure we don't use bounce buffers. */
974 blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
975
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700976 gd->queue = rq;
977
978 return 0;
979}
980
Vitaly Kuznetsovfdf9b962014-12-09 15:25:10 +0100981static const char *flush_info(unsigned int feature_flush)
982{
983 switch (feature_flush & ((REQ_FLUSH | REQ_FUA))) {
984 case REQ_FLUSH|REQ_FUA:
985 return "barrier: enabled;";
986 case REQ_FLUSH:
987 return "flush diskcache: enabled;";
988 default:
989 return "barrier or flush: disabled;";
990 }
991}
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700992
Tejun Heo4913efe2010-09-03 11:56:16 +0200993static void xlvbd_flush(struct blkfront_info *info)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -0700994{
Jens Axboebfd230a2016-03-30 10:15:21 -0600995 blk_queue_write_cache(info->rq, info->feature_flush & REQ_FLUSH,
996 info->feature_flush & REQ_FUA);
Vitaly Kuznetsovfdf9b962014-12-09 15:25:10 +0100997 pr_info("blkfront: %s: %s %s %s %s %s\n",
998 info->gd->disk_name, flush_info(info->feature_flush),
999 "persistent grants:", info->feature_persistent ?
1000 "enabled;" : "disabled;", "indirect descriptors:",
1001 info->max_indirect_segments ? "enabled;" : "disabled;");
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001002}
1003
Stefano Stabellinic80a4202010-12-02 17:55:00 +00001004static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
1005{
1006 int major;
1007 major = BLKIF_MAJOR(vdevice);
1008 *minor = BLKIF_MINOR(vdevice);
1009 switch (major) {
1010 case XEN_IDE0_MAJOR:
1011 *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET;
1012 *minor = ((*minor / 64) * PARTS_PER_DISK) +
1013 EMULATED_HD_DISK_MINOR_OFFSET;
1014 break;
1015 case XEN_IDE1_MAJOR:
1016 *offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET;
1017 *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) +
1018 EMULATED_HD_DISK_MINOR_OFFSET;
1019 break;
1020 case XEN_SCSI_DISK0_MAJOR:
1021 *offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET;
1022 *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET;
1023 break;
1024 case XEN_SCSI_DISK1_MAJOR:
1025 case XEN_SCSI_DISK2_MAJOR:
1026 case XEN_SCSI_DISK3_MAJOR:
1027 case XEN_SCSI_DISK4_MAJOR:
1028 case XEN_SCSI_DISK5_MAJOR:
1029 case XEN_SCSI_DISK6_MAJOR:
1030 case XEN_SCSI_DISK7_MAJOR:
1031 *offset = (*minor / PARTS_PER_DISK) +
1032 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) +
1033 EMULATED_SD_DISK_NAME_OFFSET;
1034 *minor = *minor +
1035 ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) +
1036 EMULATED_SD_DISK_MINOR_OFFSET;
1037 break;
1038 case XEN_SCSI_DISK8_MAJOR:
1039 case XEN_SCSI_DISK9_MAJOR:
1040 case XEN_SCSI_DISK10_MAJOR:
1041 case XEN_SCSI_DISK11_MAJOR:
1042 case XEN_SCSI_DISK12_MAJOR:
1043 case XEN_SCSI_DISK13_MAJOR:
1044 case XEN_SCSI_DISK14_MAJOR:
1045 case XEN_SCSI_DISK15_MAJOR:
1046 *offset = (*minor / PARTS_PER_DISK) +
1047 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) +
1048 EMULATED_SD_DISK_NAME_OFFSET;
1049 *minor = *minor +
1050 ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) +
1051 EMULATED_SD_DISK_MINOR_OFFSET;
1052 break;
1053 case XENVBD_MAJOR:
1054 *offset = *minor / PARTS_PER_DISK;
1055 break;
1056 default:
1057 printk(KERN_WARNING "blkfront: your disk configuration is "
1058 "incorrect, please use an xvd device instead\n");
1059 return -ENODEV;
1060 }
1061 return 0;
1062}
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001063
Jan Beuliche77c78c2012-04-05 16:37:22 +01001064static char *encode_disk_name(char *ptr, unsigned int n)
1065{
1066 if (n >= 26)
1067 ptr = encode_disk_name(ptr, n / 26 - 1);
1068 *ptr = 'a' + n % 26;
1069 return ptr + 1;
1070}
1071
Chris Lalancette9246b5f2008-09-17 14:30:32 -07001072static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
1073 struct blkfront_info *info,
Stefan Bader7c4d7d72013-05-13 16:28:15 +02001074 u16 vdisk_info, u16 sector_size,
1075 unsigned int physical_sector_size)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001076{
1077 struct gendisk *gd;
1078 int nr_minors = 1;
Stefano Stabellinic80a4202010-12-02 17:55:00 +00001079 int err;
Chris Lalancette9246b5f2008-09-17 14:30:32 -07001080 unsigned int offset;
1081 int minor;
1082 int nr_parts;
Jan Beuliche77c78c2012-04-05 16:37:22 +01001083 char *ptr;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001084
1085 BUG_ON(info->gd != NULL);
1086 BUG_ON(info->rq != NULL);
1087
Chris Lalancette9246b5f2008-09-17 14:30:32 -07001088 if ((info->vdevice>>EXT_SHIFT) > 1) {
1089 /* this is above the extended range; something is wrong */
1090 printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice);
1091 return -ENODEV;
1092 }
1093
1094 if (!VDEV_IS_EXTENDED(info->vdevice)) {
Stefano Stabellinic80a4202010-12-02 17:55:00 +00001095 err = xen_translate_vdev(info->vdevice, &minor, &offset);
1096 if (err)
1097 return err;
1098 nr_parts = PARTS_PER_DISK;
Chris Lalancette9246b5f2008-09-17 14:30:32 -07001099 } else {
1100 minor = BLKIF_MINOR_EXT(info->vdevice);
1101 nr_parts = PARTS_PER_EXT_DISK;
Stefano Stabellinic80a4202010-12-02 17:55:00 +00001102 offset = minor / nr_parts;
Stefan Bader89153b52011-07-14 15:30:37 +02001103 if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4)
Stefano Stabellinic80a4202010-12-02 17:55:00 +00001104 printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with "
1105 "emulated IDE disks,\n\t choose an xvd device name"
1106 "from xvde on\n", info->vdevice);
Chris Lalancette9246b5f2008-09-17 14:30:32 -07001107 }
Jan Beuliche77c78c2012-04-05 16:37:22 +01001108 if (minor >> MINORBITS) {
1109 pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n",
1110 info->vdevice, minor);
1111 return -ENODEV;
1112 }
Chris Lalancette9246b5f2008-09-17 14:30:32 -07001113
1114 if ((minor % nr_parts) == 0)
1115 nr_minors = nr_parts;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001116
Jan Beulich0e345822010-08-07 18:28:55 +02001117 err = xlbd_reserve_minors(minor, nr_minors);
1118 if (err)
1119 goto out;
1120 err = -ENODEV;
1121
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001122 gd = alloc_disk(nr_minors);
1123 if (gd == NULL)
Jan Beulich0e345822010-08-07 18:28:55 +02001124 goto release;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001125
Jan Beuliche77c78c2012-04-05 16:37:22 +01001126 strcpy(gd->disk_name, DEV_NAME);
1127 ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset);
1128 BUG_ON(ptr >= gd->disk_name + DISK_NAME_LEN);
1129 if (nr_minors > 1)
1130 *ptr = 0;
1131 else
1132 snprintf(ptr, gd->disk_name + DISK_NAME_LEN - ptr,
1133 "%d", minor & (nr_parts - 1));
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001134
1135 gd->major = XENVBD_MAJOR;
1136 gd->first_minor = minor;
1137 gd->fops = &xlvbd_block_fops;
1138 gd->private_data = info;
1139 gd->driverfs_dev = &(info->xbdev->dev);
1140 set_capacity(gd, capacity);
1141
Stefan Bader7c4d7d72013-05-13 16:28:15 +02001142 if (xlvbd_init_blk_queue(gd, sector_size, physical_sector_size,
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001143 info->max_indirect_segments ? :
1144 BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001145 del_gendisk(gd);
Jan Beulich0e345822010-08-07 18:28:55 +02001146 goto release;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001147 }
1148
1149 info->rq = gd->queue;
1150 info->gd = gd;
1151
Tejun Heo4913efe2010-09-03 11:56:16 +02001152 xlvbd_flush(info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001153
1154 if (vdisk_info & VDISK_READONLY)
1155 set_disk_ro(gd, 1);
1156
1157 if (vdisk_info & VDISK_REMOVABLE)
1158 gd->flags |= GENHD_FL_REMOVABLE;
1159
1160 if (vdisk_info & VDISK_CDROM)
1161 gd->flags |= GENHD_FL_CD;
1162
1163 return 0;
1164
Jan Beulich0e345822010-08-07 18:28:55 +02001165 release:
1166 xlbd_release_minors(minor, nr_minors);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001167 out:
1168 return err;
1169}
1170
Daniel Stoddena66b5ae2010-08-07 18:33:17 +02001171static void xlvbd_release_gendisk(struct blkfront_info *info)
1172{
Bob Liu3df0e502015-11-14 11:12:12 +08001173 unsigned int minor, nr_minors, i;
Daniel Stoddena66b5ae2010-08-07 18:33:17 +02001174
1175 if (info->rq == NULL)
1176 return;
1177
Daniel Stoddena66b5ae2010-08-07 18:33:17 +02001178 /* No more blkif_request(). */
Bob Liu907c3eb2015-07-13 17:55:24 +08001179 blk_mq_stop_hw_queues(info->rq);
Daniel Stoddena66b5ae2010-08-07 18:33:17 +02001180
Bob Liu3df0e502015-11-14 11:12:12 +08001181 for (i = 0; i < info->nr_rings; i++) {
1182 struct blkfront_ring_info *rinfo = &info->rinfo[i];
Daniel Stoddena66b5ae2010-08-07 18:33:17 +02001183
Bob Liu3df0e502015-11-14 11:12:12 +08001184 /* No more gnttab callback work. */
1185 gnttab_cancel_free_callback(&rinfo->callback);
1186
1187 /* Flush gnttab callback work. Must be done with no locks held. */
1188 flush_work(&rinfo->work);
1189 }
Daniel Stoddena66b5ae2010-08-07 18:33:17 +02001190
1191 del_gendisk(info->gd);
1192
1193 minor = info->gd->first_minor;
1194 nr_minors = info->gd->minors;
1195 xlbd_release_minors(minor, nr_minors);
1196
1197 blk_cleanup_queue(info->rq);
Bob Liu907c3eb2015-07-13 17:55:24 +08001198 blk_mq_free_tag_set(&info->tag_set);
Daniel Stoddena66b5ae2010-08-07 18:33:17 +02001199 info->rq = NULL;
1200
1201 put_disk(info->gd);
1202 info->gd = NULL;
1203}
1204
Bob Liu11659562015-11-14 11:12:13 +08001205/* Already hold rinfo->ring_lock. */
1206static inline void kick_pending_request_queues_locked(struct blkfront_ring_info *rinfo)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001207{
Bob Liu81f35162015-11-14 11:12:11 +08001208 if (!RING_FULL(&rinfo->ring))
1209 blk_mq_start_stopped_hw_queues(rinfo->dev_info->rq, true);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001210}
1211
Bob Liu11659562015-11-14 11:12:13 +08001212static void kick_pending_request_queues(struct blkfront_ring_info *rinfo)
1213{
1214 unsigned long flags;
1215
1216 spin_lock_irqsave(&rinfo->ring_lock, flags);
1217 kick_pending_request_queues_locked(rinfo);
1218 spin_unlock_irqrestore(&rinfo->ring_lock, flags);
1219}
1220
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001221static void blkif_restart_queue(struct work_struct *work)
1222{
Bob Liu81f35162015-11-14 11:12:11 +08001223 struct blkfront_ring_info *rinfo = container_of(work, struct blkfront_ring_info, work);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001224
Bob Liu81f35162015-11-14 11:12:11 +08001225 if (rinfo->dev_info->connected == BLKIF_STATE_CONNECTED)
1226 kick_pending_request_queues(rinfo);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001227}
1228
Bob Liu3df0e502015-11-14 11:12:12 +08001229static void blkif_free_ring(struct blkfront_ring_info *rinfo)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001230{
Bob Liu73716df2015-11-16 16:51:39 -05001231 struct grant *persistent_gnt, *n;
Bob Liu3df0e502015-11-14 11:12:12 +08001232 struct blkfront_info *info = rinfo->dev_info;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001233 int i, j, segs;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001234
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001235 /*
1236 * Remove indirect pages, this only happens when using indirect
1237 * descriptors but not persistent grants
1238 */
Bob Liu81f35162015-11-14 11:12:11 +08001239 if (!list_empty(&rinfo->indirect_pages)) {
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001240 struct page *indirect_page, *n;
1241
1242 BUG_ON(info->feature_persistent);
Bob Liu81f35162015-11-14 11:12:11 +08001243 list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001244 list_del(&indirect_page->lru);
1245 __free_page(indirect_page);
1246 }
1247 }
1248
Bob Liu73716df2015-11-16 16:51:39 -05001249 /* Remove all persistent grants. */
1250 if (!list_empty(&rinfo->grants)) {
1251 list_for_each_entry_safe(persistent_gnt, n,
1252 &rinfo->grants, node) {
1253 list_del(&persistent_gnt->node);
1254 if (persistent_gnt->gref != GRANT_INVALID_REF) {
1255 gnttab_end_foreign_access(persistent_gnt->gref,
1256 0, 0UL);
1257 rinfo->persistent_gnts_c--;
1258 }
1259 if (info->feature_persistent)
1260 __free_page(persistent_gnt->page);
1261 kfree(persistent_gnt);
1262 }
1263 }
1264 BUG_ON(rinfo->persistent_gnts_c != 0);
1265
Bob Liu86839c52015-06-03 13:40:03 +08001266 for (i = 0; i < BLK_RING_SIZE(info); i++) {
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001267 /*
1268 * Clear persistent grants present in requests already
1269 * on the shared ring
1270 */
Bob Liu81f35162015-11-14 11:12:11 +08001271 if (!rinfo->shadow[i].request)
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001272 goto free_shadow;
1273
Bob Liu81f35162015-11-14 11:12:11 +08001274 segs = rinfo->shadow[i].req.operation == BLKIF_OP_INDIRECT ?
1275 rinfo->shadow[i].req.u.indirect.nr_segments :
1276 rinfo->shadow[i].req.u.rw.nr_segments;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001277 for (j = 0; j < segs; j++) {
Bob Liu81f35162015-11-14 11:12:11 +08001278 persistent_gnt = rinfo->shadow[i].grants_used[j];
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001279 gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001280 if (info->feature_persistent)
Julien Gralla7a6df22015-06-30 11:58:51 +01001281 __free_page(persistent_gnt->page);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001282 kfree(persistent_gnt);
1283 }
1284
Bob Liu81f35162015-11-14 11:12:11 +08001285 if (rinfo->shadow[i].req.operation != BLKIF_OP_INDIRECT)
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001286 /*
1287 * If this is not an indirect operation don't try to
1288 * free indirect segments
1289 */
1290 goto free_shadow;
1291
1292 for (j = 0; j < INDIRECT_GREFS(segs); j++) {
Bob Liu81f35162015-11-14 11:12:11 +08001293 persistent_gnt = rinfo->shadow[i].indirect_grants[j];
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001294 gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
Julien Gralla7a6df22015-06-30 11:58:51 +01001295 __free_page(persistent_gnt->page);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001296 kfree(persistent_gnt);
1297 }
1298
1299free_shadow:
Bob Liu81f35162015-11-14 11:12:11 +08001300 kfree(rinfo->shadow[i].grants_used);
1301 rinfo->shadow[i].grants_used = NULL;
1302 kfree(rinfo->shadow[i].indirect_grants);
1303 rinfo->shadow[i].indirect_grants = NULL;
1304 kfree(rinfo->shadow[i].sg);
1305 rinfo->shadow[i].sg = NULL;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001306 }
1307
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001308 /* No more gnttab callback work. */
Bob Liu81f35162015-11-14 11:12:11 +08001309 gnttab_cancel_free_callback(&rinfo->callback);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001310
1311 /* Flush gnttab callback work. Must be done with no locks held. */
Bob Liu81f35162015-11-14 11:12:11 +08001312 flush_work(&rinfo->work);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001313
1314 /* Free resources associated with old device channel. */
Bob Liu86839c52015-06-03 13:40:03 +08001315 for (i = 0; i < info->nr_ring_pages; i++) {
Bob Liu81f35162015-11-14 11:12:11 +08001316 if (rinfo->ring_ref[i] != GRANT_INVALID_REF) {
1317 gnttab_end_foreign_access(rinfo->ring_ref[i], 0, 0);
1318 rinfo->ring_ref[i] = GRANT_INVALID_REF;
Bob Liu86839c52015-06-03 13:40:03 +08001319 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001320 }
Bob Liu81f35162015-11-14 11:12:11 +08001321 free_pages((unsigned long)rinfo->ring.sring, get_order(info->nr_ring_pages * PAGE_SIZE));
1322 rinfo->ring.sring = NULL;
Bob Liu86839c52015-06-03 13:40:03 +08001323
Bob Liu81f35162015-11-14 11:12:11 +08001324 if (rinfo->irq)
1325 unbind_from_irqhandler(rinfo->irq, rinfo);
1326 rinfo->evtchn = rinfo->irq = 0;
Bob Liu3df0e502015-11-14 11:12:12 +08001327}
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001328
Bob Liu3df0e502015-11-14 11:12:12 +08001329static void blkif_free(struct blkfront_info *info, int suspend)
1330{
Bob Liu3df0e502015-11-14 11:12:12 +08001331 unsigned int i;
1332
1333 /* Prevent new requests being issued until we fix things up. */
Bob Liu3df0e502015-11-14 11:12:12 +08001334 info->connected = suspend ?
1335 BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
1336 /* No more blkif_request(). */
1337 if (info->rq)
1338 blk_mq_stop_hw_queues(info->rq);
1339
Bob Liu3df0e502015-11-14 11:12:12 +08001340 for (i = 0; i < info->nr_rings; i++)
1341 blkif_free_ring(&info->rinfo[i]);
1342
1343 kfree(info->rinfo);
1344 info->rinfo = NULL;
1345 info->nr_rings = 0;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001346}
1347
Julien Grallc004a6f2015-07-22 16:44:54 +01001348struct copy_from_grant {
1349 const struct blk_shadow *s;
1350 unsigned int grant_idx;
1351 unsigned int bvec_offset;
1352 char *bvec_data;
1353};
1354
1355static void blkif_copy_from_grant(unsigned long gfn, unsigned int offset,
1356 unsigned int len, void *data)
1357{
1358 struct copy_from_grant *info = data;
1359 char *shared_data;
1360 /* Convenient aliases */
1361 const struct blk_shadow *s = info->s;
1362
1363 shared_data = kmap_atomic(s->grants_used[info->grant_idx]->page);
1364
1365 memcpy(info->bvec_data + info->bvec_offset,
1366 shared_data + offset, len);
1367
1368 info->bvec_offset += len;
1369 info->grant_idx++;
1370
1371 kunmap_atomic(shared_data);
1372}
1373
Julien Grall6cc568332015-08-13 13:13:35 +01001374static enum blk_req_status blkif_rsp_to_req_status(int rsp)
1375{
1376 switch (rsp)
1377 {
1378 case BLKIF_RSP_OKAY:
1379 return REQ_DONE;
1380 case BLKIF_RSP_EOPNOTSUPP:
1381 return REQ_EOPNOTSUPP;
1382 case BLKIF_RSP_ERROR:
1383 /* Fallthrough. */
1384 default:
1385 return REQ_ERROR;
1386 }
1387}
1388
1389/*
1390 * Get the final status of the block request based on two ring response
1391 */
1392static int blkif_get_final_status(enum blk_req_status s1,
1393 enum blk_req_status s2)
1394{
1395 BUG_ON(s1 == REQ_WAITING);
1396 BUG_ON(s2 == REQ_WAITING);
1397
1398 if (s1 == REQ_ERROR || s2 == REQ_ERROR)
1399 return BLKIF_RSP_ERROR;
1400 else if (s1 == REQ_EOPNOTSUPP || s2 == REQ_EOPNOTSUPP)
1401 return BLKIF_RSP_EOPNOTSUPP;
1402 return BLKIF_RSP_OKAY;
1403}
1404
1405static bool blkif_completion(unsigned long *id,
1406 struct blkfront_ring_info *rinfo,
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001407 struct blkif_response *bret)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001408{
Roger Pau Monned62f6912012-12-07 19:00:31 +01001409 int i = 0;
Roger Pau Monneb7649152013-05-02 10:58:50 +02001410 struct scatterlist *sg;
Julien Grallc004a6f2015-07-22 16:44:54 +01001411 int num_sg, num_grant;
Bob Liu81f35162015-11-14 11:12:11 +08001412 struct blkfront_info *info = rinfo->dev_info;
Julien Grall6cc568332015-08-13 13:13:35 +01001413 struct blk_shadow *s = &rinfo->shadow[*id];
Julien Grallc004a6f2015-07-22 16:44:54 +01001414 struct copy_from_grant data = {
Julien Grallc004a6f2015-07-22 16:44:54 +01001415 .grant_idx = 0,
1416 };
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001417
Julien Grallc004a6f2015-07-22 16:44:54 +01001418 num_grant = s->req.operation == BLKIF_OP_INDIRECT ?
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001419 s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments;
Julien Grall6cc568332015-08-13 13:13:35 +01001420
1421 /* The I/O request may be split in two. */
1422 if (unlikely(s->associated_id != NO_ASSOCIATED_ID)) {
1423 struct blk_shadow *s2 = &rinfo->shadow[s->associated_id];
1424
1425 /* Keep the status of the current response in shadow. */
1426 s->status = blkif_rsp_to_req_status(bret->status);
1427
1428 /* Wait the second response if not yet here. */
1429 if (s2->status == REQ_WAITING)
1430 return 0;
1431
1432 bret->status = blkif_get_final_status(s->status,
1433 s2->status);
1434
1435 /*
1436 * All the grants is stored in the first shadow in order
1437 * to make the completion code simpler.
1438 */
1439 num_grant += s2->req.u.rw.nr_segments;
1440
1441 /*
1442 * The two responses may not come in order. Only the
1443 * first request will store the scatter-gather list.
1444 */
1445 if (s2->num_sg != 0) {
1446 /* Update "id" with the ID of the first response. */
1447 *id = s->associated_id;
1448 s = s2;
1449 }
1450
1451 /*
1452 * We don't need anymore the second request, so recycling
1453 * it now.
1454 */
1455 if (add_id_to_freelist(rinfo, s->associated_id))
1456 WARN(1, "%s: can't recycle the second part (id = %ld) of the request\n",
1457 info->gd->disk_name, s->associated_id);
1458 }
1459
1460 data.s = s;
Julien Grallc004a6f2015-07-22 16:44:54 +01001461 num_sg = s->num_sg;
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001462
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001463 if (bret->operation == BLKIF_OP_READ && info->feature_persistent) {
Julien Grallc004a6f2015-07-22 16:44:54 +01001464 for_each_sg(s->sg, sg, num_sg, i) {
Roger Pau Monneb7649152013-05-02 10:58:50 +02001465 BUG_ON(sg->offset + sg->length > PAGE_SIZE);
Julien Grallc004a6f2015-07-22 16:44:54 +01001466
1467 data.bvec_offset = sg->offset;
1468 data.bvec_data = kmap_atomic(sg_page(sg));
1469
1470 gnttab_foreach_grant_in_range(sg_page(sg),
1471 sg->offset,
1472 sg->length,
1473 blkif_copy_from_grant,
1474 &data);
1475
1476 kunmap_atomic(data.bvec_data);
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001477 }
1478 }
1479 /* Add the persistent grant into the list of free grants */
Julien Grallc004a6f2015-07-22 16:44:54 +01001480 for (i = 0; i < num_grant; i++) {
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001481 if (gnttab_query_foreign_access(s->grants_used[i]->gref)) {
1482 /*
1483 * If the grant is still mapped by the backend (the
1484 * backend has chosen to make this grant persistent)
1485 * we add it at the head of the list, so it will be
1486 * reused first.
1487 */
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001488 if (!info->feature_persistent)
1489 pr_alert_ratelimited("backed has not unmapped grant: %u\n",
1490 s->grants_used[i]->gref);
Bob Liu73716df2015-11-16 16:51:39 -05001491 list_add(&s->grants_used[i]->node, &rinfo->grants);
1492 rinfo->persistent_gnts_c++;
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001493 } else {
1494 /*
1495 * If the grant is not mapped by the backend we end the
1496 * foreign access and add it to the tail of the list,
1497 * so it will not be picked again unless we run out of
1498 * persistent grants.
1499 */
1500 gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL);
1501 s->grants_used[i]->gref = GRANT_INVALID_REF;
Bob Liu73716df2015-11-16 16:51:39 -05001502 list_add_tail(&s->grants_used[i]->node, &rinfo->grants);
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001503 }
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001504 }
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001505 if (s->req.operation == BLKIF_OP_INDIRECT) {
Julien Grallc004a6f2015-07-22 16:44:54 +01001506 for (i = 0; i < INDIRECT_GREFS(num_grant); i++) {
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001507 if (gnttab_query_foreign_access(s->indirect_grants[i]->gref)) {
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001508 if (!info->feature_persistent)
1509 pr_alert_ratelimited("backed has not unmapped grant: %u\n",
1510 s->indirect_grants[i]->gref);
Bob Liu73716df2015-11-16 16:51:39 -05001511 list_add(&s->indirect_grants[i]->node, &rinfo->grants);
1512 rinfo->persistent_gnts_c++;
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001513 } else {
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001514 struct page *indirect_page;
1515
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001516 gnttab_end_foreign_access(s->indirect_grants[i]->gref, 0, 0UL);
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01001517 /*
1518 * Add the used indirect page back to the list of
1519 * available pages for indirect grefs.
1520 */
Bob Liu7b076752015-07-22 14:40:09 +08001521 if (!info->feature_persistent) {
Julien Gralla7a6df22015-06-30 11:58:51 +01001522 indirect_page = s->indirect_grants[i]->page;
Bob Liu81f35162015-11-14 11:12:11 +08001523 list_add(&indirect_page->lru, &rinfo->indirect_pages);
Bob Liu7b076752015-07-22 14:40:09 +08001524 }
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001525 s->indirect_grants[i]->gref = GRANT_INVALID_REF;
Bob Liu73716df2015-11-16 16:51:39 -05001526 list_add_tail(&s->indirect_grants[i]->node, &rinfo->grants);
Roger Pau Monnefbe363c2013-08-12 12:53:44 +02001527 }
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001528 }
1529 }
Julien Grall6cc568332015-08-13 13:13:35 +01001530
1531 return 1;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001532}
1533
1534static irqreturn_t blkif_interrupt(int irq, void *dev_id)
1535{
1536 struct request *req;
1537 struct blkif_response *bret;
1538 RING_IDX i, rp;
1539 unsigned long flags;
Bob Liu81f35162015-11-14 11:12:11 +08001540 struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)dev_id;
1541 struct blkfront_info *info = rinfo->dev_info;
Christoph Hellwigf4829a92015-09-27 21:01:50 +02001542 int error;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001543
Bob Liu11659562015-11-14 11:12:13 +08001544 if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001545 return IRQ_HANDLED;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001546
Bob Liu11659562015-11-14 11:12:13 +08001547 spin_lock_irqsave(&rinfo->ring_lock, flags);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001548 again:
Bob Liu81f35162015-11-14 11:12:11 +08001549 rp = rinfo->ring.sring->rsp_prod;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001550 rmb(); /* Ensure we see queued responses up to 'rp'. */
1551
Bob Liu81f35162015-11-14 11:12:11 +08001552 for (i = rinfo->ring.rsp_cons; i != rp; i++) {
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001553 unsigned long id;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001554
Bob Liu81f35162015-11-14 11:12:11 +08001555 bret = RING_GET_RESPONSE(&rinfo->ring, i);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001556 id = bret->id;
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -04001557 /*
1558 * The backend has messed up and given us an id that we would
1559 * never have given to it (we stamp it up to BLK_RING_SIZE -
1560 * look in get_id_from_freelist.
1561 */
Bob Liu86839c52015-06-03 13:40:03 +08001562 if (id >= BLK_RING_SIZE(info)) {
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -04001563 WARN(1, "%s: response to %s has incorrect id (%ld)\n",
1564 info->gd->disk_name, op_name(bret->operation), id);
1565 /* We can't safely get the 'struct request' as
1566 * the id is busted. */
1567 continue;
1568 }
Bob Liu81f35162015-11-14 11:12:11 +08001569 req = rinfo->shadow[id].request;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001570
Julien Grall6cc568332015-08-13 13:13:35 +01001571 if (bret->operation != BLKIF_OP_DISCARD) {
1572 /*
1573 * We may need to wait for an extra response if the
1574 * I/O request is split in 2
1575 */
1576 if (!blkif_completion(&id, rinfo, bret))
1577 continue;
1578 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001579
Bob Liu81f35162015-11-14 11:12:11 +08001580 if (add_id_to_freelist(rinfo, id)) {
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -04001581 WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n",
1582 info->gd->disk_name, op_name(bret->operation), id);
1583 continue;
1584 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001585
Christoph Hellwigf4829a92015-09-27 21:01:50 +02001586 error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001587 switch (bret->operation) {
Li Dongyanged30bf32011-09-01 18:39:09 +08001588 case BLKIF_OP_DISCARD:
1589 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
1590 struct request_queue *rq = info->rq;
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -04001591 printk(KERN_WARNING "blkfront: %s: %s op failed\n",
1592 info->gd->disk_name, op_name(bret->operation));
Christoph Hellwigf4829a92015-09-27 21:01:50 +02001593 error = -EOPNOTSUPP;
Li Dongyanged30bf32011-09-01 18:39:09 +08001594 info->feature_discard = 0;
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -04001595 info->feature_secdiscard = 0;
Li Dongyanged30bf32011-09-01 18:39:09 +08001596 queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -04001597 queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq);
Li Dongyanged30bf32011-09-01 18:39:09 +08001598 }
Christoph Hellwigf4829a92015-09-27 21:01:50 +02001599 blk_mq_complete_request(req, error);
Li Dongyanged30bf32011-09-01 18:39:09 +08001600 break;
Konrad Rzeszutek Wilkedf6ef52011-05-03 12:01:11 -04001601 case BLKIF_OP_FLUSH_DISKCACHE:
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001602 case BLKIF_OP_WRITE_BARRIER:
1603 if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -04001604 printk(KERN_WARNING "blkfront: %s: %s op failed\n",
1605 info->gd->disk_name, op_name(bret->operation));
Christoph Hellwigf4829a92015-09-27 21:01:50 +02001606 error = -EOPNOTSUPP;
Jeremy Fitzhardingedcb8bae2010-11-02 11:55:58 -04001607 }
1608 if (unlikely(bret->status == BLKIF_RSP_ERROR &&
Bob Liu81f35162015-11-14 11:12:11 +08001609 rinfo->shadow[id].req.u.rw.nr_segments == 0)) {
Konrad Rzeszutek Wilk6878c322012-05-25 17:34:51 -04001610 printk(KERN_WARNING "blkfront: %s: empty %s op failed\n",
1611 info->gd->disk_name, op_name(bret->operation));
Christoph Hellwigf4829a92015-09-27 21:01:50 +02001612 error = -EOPNOTSUPP;
Jeremy Fitzhardingedcb8bae2010-11-02 11:55:58 -04001613 }
Christoph Hellwigf4829a92015-09-27 21:01:50 +02001614 if (unlikely(error)) {
1615 if (error == -EOPNOTSUPP)
1616 error = 0;
Tejun Heo4913efe2010-09-03 11:56:16 +02001617 info->feature_flush = 0;
1618 xlvbd_flush(info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001619 }
1620 /* fall through */
1621 case BLKIF_OP_READ:
1622 case BLKIF_OP_WRITE:
1623 if (unlikely(bret->status != BLKIF_RSP_OKAY))
1624 dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
1625 "request: %x\n", bret->status);
1626
Christoph Hellwigf4829a92015-09-27 21:01:50 +02001627 blk_mq_complete_request(req, error);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001628 break;
1629 default:
1630 BUG();
1631 }
1632 }
1633
Bob Liu81f35162015-11-14 11:12:11 +08001634 rinfo->ring.rsp_cons = i;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001635
Bob Liu81f35162015-11-14 11:12:11 +08001636 if (i != rinfo->ring.req_prod_pvt) {
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001637 int more_to_do;
Bob Liu81f35162015-11-14 11:12:11 +08001638 RING_FINAL_CHECK_FOR_RESPONSES(&rinfo->ring, more_to_do);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001639 if (more_to_do)
1640 goto again;
1641 } else
Bob Liu81f35162015-11-14 11:12:11 +08001642 rinfo->ring.sring->rsp_event = i + 1;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001643
Bob Liu11659562015-11-14 11:12:13 +08001644 kick_pending_request_queues_locked(rinfo);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001645
Bob Liu11659562015-11-14 11:12:13 +08001646 spin_unlock_irqrestore(&rinfo->ring_lock, flags);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001647
1648 return IRQ_HANDLED;
1649}
1650
1651
1652static int setup_blkring(struct xenbus_device *dev,
Bob Liu81f35162015-11-14 11:12:11 +08001653 struct blkfront_ring_info *rinfo)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001654{
1655 struct blkif_sring *sring;
Bob Liu86839c52015-06-03 13:40:03 +08001656 int err, i;
Bob Liu81f35162015-11-14 11:12:11 +08001657 struct blkfront_info *info = rinfo->dev_info;
Julien Grallc004a6f2015-07-22 16:44:54 +01001658 unsigned long ring_size = info->nr_ring_pages * XEN_PAGE_SIZE;
Julien Grall9cce2912015-10-13 17:50:11 +01001659 grant_ref_t gref[XENBUS_MAX_RING_GRANTS];
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001660
Bob Liu86839c52015-06-03 13:40:03 +08001661 for (i = 0; i < info->nr_ring_pages; i++)
Bob Liu81f35162015-11-14 11:12:11 +08001662 rinfo->ring_ref[i] = GRANT_INVALID_REF;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001663
Bob Liu86839c52015-06-03 13:40:03 +08001664 sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH,
1665 get_order(ring_size));
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001666 if (!sring) {
1667 xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
1668 return -ENOMEM;
1669 }
1670 SHARED_RING_INIT(sring);
Bob Liu81f35162015-11-14 11:12:11 +08001671 FRONT_RING_INIT(&rinfo->ring, sring, ring_size);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001672
Bob Liu81f35162015-11-14 11:12:11 +08001673 err = xenbus_grant_ring(dev, rinfo->ring.sring, info->nr_ring_pages, gref);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001674 if (err < 0) {
Bob Liu86839c52015-06-03 13:40:03 +08001675 free_pages((unsigned long)sring, get_order(ring_size));
Bob Liu81f35162015-11-14 11:12:11 +08001676 rinfo->ring.sring = NULL;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001677 goto fail;
1678 }
Bob Liu86839c52015-06-03 13:40:03 +08001679 for (i = 0; i < info->nr_ring_pages; i++)
Bob Liu81f35162015-11-14 11:12:11 +08001680 rinfo->ring_ref[i] = gref[i];
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001681
Bob Liu81f35162015-11-14 11:12:11 +08001682 err = xenbus_alloc_evtchn(dev, &rinfo->evtchn);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001683 if (err)
1684 goto fail;
1685
Bob Liu81f35162015-11-14 11:12:11 +08001686 err = bind_evtchn_to_irqhandler(rinfo->evtchn, blkif_interrupt, 0,
1687 "blkif", rinfo);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001688 if (err <= 0) {
1689 xenbus_dev_fatal(dev, err,
1690 "bind_evtchn_to_irqhandler failed");
1691 goto fail;
1692 }
Bob Liu81f35162015-11-14 11:12:11 +08001693 rinfo->irq = err;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001694
1695 return 0;
1696fail:
1697 blkif_free(info, 0);
1698 return err;
1699}
1700
Bob Liu28d949b2015-11-14 11:12:14 +08001701/*
1702 * Write out per-ring/queue nodes including ring-ref and event-channel, and each
1703 * ring buffer may have multi pages depending on ->nr_ring_pages.
1704 */
1705static int write_per_ring_nodes(struct xenbus_transaction xbt,
1706 struct blkfront_ring_info *rinfo, const char *dir)
1707{
1708 int err;
1709 unsigned int i;
1710 const char *message = NULL;
1711 struct blkfront_info *info = rinfo->dev_info;
1712
1713 if (info->nr_ring_pages == 1) {
1714 err = xenbus_printf(xbt, dir, "ring-ref", "%u", rinfo->ring_ref[0]);
1715 if (err) {
1716 message = "writing ring-ref";
1717 goto abort_transaction;
1718 }
1719 } else {
1720 for (i = 0; i < info->nr_ring_pages; i++) {
1721 char ring_ref_name[RINGREF_NAME_LEN];
1722
1723 snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i);
1724 err = xenbus_printf(xbt, dir, ring_ref_name,
1725 "%u", rinfo->ring_ref[i]);
1726 if (err) {
1727 message = "writing ring-ref";
1728 goto abort_transaction;
1729 }
1730 }
1731 }
1732
1733 err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn);
1734 if (err) {
1735 message = "writing event-channel";
1736 goto abort_transaction;
1737 }
1738
1739 return 0;
1740
1741abort_transaction:
1742 xenbus_transaction_end(xbt, 1);
1743 if (message)
1744 xenbus_dev_fatal(info->xbdev, err, "%s", message);
1745
1746 return err;
1747}
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001748
1749/* Common code used when first setting up, and when resuming. */
Ian Campbell203fd612009-12-04 15:33:54 +00001750static int talk_to_blkback(struct xenbus_device *dev,
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001751 struct blkfront_info *info)
1752{
1753 const char *message = NULL;
1754 struct xenbus_transaction xbt;
Bob Liu28d949b2015-11-14 11:12:14 +08001755 int err;
1756 unsigned int i, max_page_order = 0;
Bob Liu86839c52015-06-03 13:40:03 +08001757 unsigned int ring_page_order = 0;
1758
1759 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1760 "max-ring-page-order", "%u", &max_page_order);
1761 if (err != 1)
1762 info->nr_ring_pages = 1;
1763 else {
1764 ring_page_order = min(xen_blkif_max_ring_order, max_page_order);
1765 info->nr_ring_pages = 1 << ring_page_order;
1766 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001767
Bob Liu3df0e502015-11-14 11:12:12 +08001768 for (i = 0; i < info->nr_rings; i++) {
Bob Liu28d949b2015-11-14 11:12:14 +08001769 struct blkfront_ring_info *rinfo = &info->rinfo[i];
1770
Bob Liu3df0e502015-11-14 11:12:12 +08001771 /* Create shared ring, alloc event channel. */
1772 err = setup_blkring(dev, rinfo);
1773 if (err)
1774 goto destroy_blkring;
1775 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001776
1777again:
1778 err = xenbus_transaction_start(&xbt);
1779 if (err) {
1780 xenbus_dev_fatal(dev, err, "starting transaction");
1781 goto destroy_blkring;
1782 }
1783
Bob Liu28d949b2015-11-14 11:12:14 +08001784 if (info->nr_ring_pages > 1) {
1785 err = xenbus_printf(xbt, dev->nodename, "ring-page-order", "%u",
1786 ring_page_order);
Bob Liu3df0e502015-11-14 11:12:12 +08001787 if (err) {
Bob Liu28d949b2015-11-14 11:12:14 +08001788 message = "writing ring-page-order";
Bob Liu3df0e502015-11-14 11:12:12 +08001789 goto abort_transaction;
1790 }
Bob Liu28d949b2015-11-14 11:12:14 +08001791 }
1792
1793 /* We already got the number of queues/rings in _probe */
1794 if (info->nr_rings == 1) {
1795 err = write_per_ring_nodes(xbt, &info->rinfo[0], dev->nodename);
1796 if (err)
1797 goto destroy_blkring;
Bob Liu3df0e502015-11-14 11:12:12 +08001798 } else {
Bob Liu28d949b2015-11-14 11:12:14 +08001799 char *path;
1800 size_t pathsize;
1801
1802 err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues", "%u",
1803 info->nr_rings);
1804 if (err) {
1805 message = "writing multi-queue-num-queues";
1806 goto abort_transaction;
1807 }
1808
1809 pathsize = strlen(dev->nodename) + QUEUE_NAME_LEN;
1810 path = kmalloc(pathsize, GFP_KERNEL);
1811 if (!path) {
1812 err = -ENOMEM;
1813 message = "ENOMEM while writing ring references";
1814 goto abort_transaction;
1815 }
1816
1817 for (i = 0; i < info->nr_rings; i++) {
1818 memset(path, 0, pathsize);
1819 snprintf(path, pathsize, "%s/queue-%u", dev->nodename, i);
1820 err = write_per_ring_nodes(xbt, &info->rinfo[i], path);
1821 if (err) {
1822 kfree(path);
1823 goto destroy_blkring;
1824 }
1825 }
1826 kfree(path);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001827 }
Markus Armbruster3e334232008-04-02 10:54:02 -07001828 err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
1829 XEN_IO_PROTO_ABI_NATIVE);
1830 if (err) {
1831 message = "writing protocol";
1832 goto abort_transaction;
1833 }
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001834 err = xenbus_printf(xbt, dev->nodename,
Roger Pau Monnecb5bd4d2012-11-02 16:43:04 +01001835 "feature-persistent", "%u", 1);
Roger Pau Monne0a8704a2012-10-24 18:58:45 +02001836 if (err)
1837 dev_warn(&dev->dev,
1838 "writing persistent grants feature to xenbus");
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001839
1840 err = xenbus_transaction_end(xbt, 0);
1841 if (err) {
1842 if (err == -EAGAIN)
1843 goto again;
1844 xenbus_dev_fatal(dev, err, "completing transaction");
1845 goto destroy_blkring;
1846 }
1847
Bob Liu3df0e502015-11-14 11:12:12 +08001848 for (i = 0; i < info->nr_rings; i++) {
1849 unsigned int j;
Bob Liu28d949b2015-11-14 11:12:14 +08001850 struct blkfront_ring_info *rinfo = &info->rinfo[i];
Bob Liu3df0e502015-11-14 11:12:12 +08001851
1852 for (j = 0; j < BLK_RING_SIZE(info); j++)
1853 rinfo->shadow[j].req.u.rw.id = j + 1;
1854 rinfo->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff;
1855 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001856 xenbus_switch_state(dev, XenbusStateInitialised);
1857
1858 return 0;
1859
1860 abort_transaction:
1861 xenbus_transaction_end(xbt, 1);
1862 if (message)
1863 xenbus_dev_fatal(dev, err, "%s", message);
1864 destroy_blkring:
1865 blkif_free(info, 0);
Bob Liu3df0e502015-11-14 11:12:12 +08001866
Konrad Rzeszutek Wilkc31ecf62015-12-18 16:28:53 -05001867 kfree(info);
1868 dev_set_drvdata(&dev->dev, NULL);
1869
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001870 return err;
1871}
1872
Bob Liu3db70a82015-11-25 17:52:55 -05001873static int negotiate_mq(struct blkfront_info *info)
1874{
1875 unsigned int backend_max_queues = 0;
1876 int err;
1877 unsigned int i;
1878
1879 BUG_ON(info->nr_rings);
1880
1881 /* Check if backend supports multiple queues. */
1882 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1883 "multi-queue-max-queues", "%u", &backend_max_queues);
1884 if (err < 0)
1885 backend_max_queues = 1;
1886
1887 info->nr_rings = min(backend_max_queues, xen_blkif_max_queues);
1888 /* We need at least one ring. */
1889 if (!info->nr_rings)
1890 info->nr_rings = 1;
1891
1892 info->rinfo = kzalloc(sizeof(struct blkfront_ring_info) * info->nr_rings, GFP_KERNEL);
1893 if (!info->rinfo) {
1894 xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure");
1895 return -ENOMEM;
1896 }
1897
1898 for (i = 0; i < info->nr_rings; i++) {
1899 struct blkfront_ring_info *rinfo;
1900
1901 rinfo = &info->rinfo[i];
1902 INIT_LIST_HEAD(&rinfo->indirect_pages);
1903 INIT_LIST_HEAD(&rinfo->grants);
1904 rinfo->dev_info = info;
1905 INIT_WORK(&rinfo->work, blkif_restart_queue);
1906 spin_lock_init(&rinfo->ring_lock);
1907 }
1908 return 0;
1909}
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001910/**
1911 * Entry point to this code when a new device is created. Allocate the basic
1912 * structures and the ring buffer for communication with the backend, and
1913 * inform the backend of the appropriate details for those. Switch to
1914 * Initialised state.
1915 */
1916static int blkfront_probe(struct xenbus_device *dev,
1917 const struct xenbus_device_id *id)
1918{
Bob Liu86839c52015-06-03 13:40:03 +08001919 int err, vdevice;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001920 struct blkfront_info *info;
1921
1922 /* FIXME: Use dynamic device id if this is not set. */
1923 err = xenbus_scanf(XBT_NIL, dev->nodename,
1924 "virtual-device", "%i", &vdevice);
1925 if (err != 1) {
Chris Lalancette9246b5f2008-09-17 14:30:32 -07001926 /* go looking in the extended area instead */
1927 err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext",
1928 "%i", &vdevice);
1929 if (err != 1) {
1930 xenbus_dev_fatal(dev, err, "reading virtual-device");
1931 return err;
1932 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001933 }
1934
Stefano Stabellinib98a4092010-07-29 14:53:16 +01001935 if (xen_hvm_domain()) {
1936 char *type;
1937 int len;
1938 /* no unplug has been done: do not hook devices != xen vbds */
Konrad Rzeszutek Wilk51c71a32013-11-26 15:05:40 -05001939 if (xen_has_pv_and_legacy_disk_devices()) {
Stefano Stabellinib98a4092010-07-29 14:53:16 +01001940 int major;
Stefano Stabellinic1c54132010-05-14 12:44:30 +01001941
Stefano Stabellinib98a4092010-07-29 14:53:16 +01001942 if (!VDEV_IS_EXTENDED(vdevice))
1943 major = BLKIF_MAJOR(vdevice);
1944 else
1945 major = XENVBD_MAJOR;
Stefano Stabellinic1c54132010-05-14 12:44:30 +01001946
Stefano Stabellinib98a4092010-07-29 14:53:16 +01001947 if (major != XENVBD_MAJOR) {
1948 printk(KERN_INFO
1949 "%s: HVM does not support vbd %d as xen block device\n",
Rasmus Villemoes02f1f212015-02-12 15:01:31 -08001950 __func__, vdevice);
Stefano Stabellinib98a4092010-07-29 14:53:16 +01001951 return -ENODEV;
1952 }
1953 }
1954 /* do not create a PV cdrom device if we are an HVM guest */
1955 type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
1956 if (IS_ERR(type))
1957 return -ENODEV;
1958 if (strncmp(type, "cdrom", 5) == 0) {
1959 kfree(type);
Stefano Stabellinic1c54132010-05-14 12:44:30 +01001960 return -ENODEV;
1961 }
Stefano Stabellinib98a4092010-07-29 14:53:16 +01001962 kfree(type);
Stefano Stabellinic1c54132010-05-14 12:44:30 +01001963 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001964 info = kzalloc(sizeof(*info), GFP_KERNEL);
1965 if (!info) {
1966 xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
1967 return -ENOMEM;
1968 }
1969
Bob Liu28d949b2015-11-14 11:12:14 +08001970 info->xbdev = dev;
Bob Liu3db70a82015-11-25 17:52:55 -05001971 err = negotiate_mq(info);
1972 if (err) {
Bob Liu3df0e502015-11-14 11:12:12 +08001973 kfree(info);
Bob Liu3db70a82015-11-25 17:52:55 -05001974 return err;
Bob Liu3df0e502015-11-14 11:12:12 +08001975 }
Bob Liu81f35162015-11-14 11:12:11 +08001976
Daniel Stoddenb70f5fa2010-04-30 22:01:19 +00001977 mutex_init(&info->mutex);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001978 info->vdevice = vdevice;
1979 info->connected = BLKIF_STATE_DISCONNECTED;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001980
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001981 /* Front end dir is a number, which is used as the id. */
1982 info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
Greg Kroah-Hartmana1b4b122009-04-30 14:43:31 -07001983 dev_set_drvdata(&dev->dev, info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001984
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07001985 return 0;
1986}
1987
Christoph Hellwig4246a0b2015-07-20 15:29:37 +02001988static void split_bio_end(struct bio *bio)
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001989{
1990 struct split_bio *split_bio = bio->bi_private;
1991
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001992 if (atomic_dec_and_test(&split_bio->pending)) {
1993 split_bio->bio->bi_phys_segments = 0;
Christoph Hellwig4246a0b2015-07-20 15:29:37 +02001994 split_bio->bio->bi_error = bio->bi_error;
1995 bio_endio(split_bio->bio);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02001996 kfree(split_bio);
1997 }
1998 bio_put(bio);
1999}
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002000
2001static int blkif_recover(struct blkfront_info *info)
2002{
Bob Liu3df0e502015-11-14 11:12:12 +08002003 unsigned int i, r_index;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002004 struct request *req, *n;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002005 struct blk_shadow *copy;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002006 int rc;
2007 struct bio *bio, *cloned_bio;
2008 struct bio_list bio_list, merge_bio;
2009 unsigned int segs, offset;
2010 int pending, size;
2011 struct split_bio *split_bio;
2012 struct list_head requests;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002013
Bob Liu3df0e502015-11-14 11:12:12 +08002014 blkfront_gather_backend_features(info);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002015 segs = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST;
2016 blk_queue_max_segments(info->rq, segs);
2017 bio_list_init(&bio_list);
2018 INIT_LIST_HEAD(&requests);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002019
Bob Liu3df0e502015-11-14 11:12:12 +08002020 for (r_index = 0; r_index < info->nr_rings; r_index++) {
2021 struct blkfront_ring_info *rinfo;
2022
2023 rinfo = &info->rinfo[r_index];
2024 /* Stage 1: Make a safe copy of the shadow state. */
2025 copy = kmemdup(rinfo->shadow, sizeof(rinfo->shadow),
2026 GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
2027 if (!copy)
2028 return -ENOMEM;
2029
2030 /* Stage 2: Set up free list. */
2031 memset(&rinfo->shadow, 0, sizeof(rinfo->shadow));
2032 for (i = 0; i < BLK_RING_SIZE(info); i++)
2033 rinfo->shadow[i].req.u.rw.id = i+1;
2034 rinfo->shadow_free = rinfo->ring.req_prod_pvt;
2035 rinfo->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff;
2036
2037 rc = blkfront_setup_indirect(rinfo);
2038 if (rc) {
2039 kfree(copy);
2040 return rc;
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -04002041 }
Bob Liu3df0e502015-11-14 11:12:12 +08002042
2043 for (i = 0; i < BLK_RING_SIZE(info); i++) {
2044 /* Not in use? */
2045 if (!copy[i].request)
2046 continue;
2047
2048 /*
2049 * Get the bios in the request so we can re-queue them.
2050 */
2051 if (copy[i].request->cmd_flags &
2052 (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
2053 /*
2054 * Flush operations don't contain bios, so
2055 * we need to requeue the whole request
2056 */
2057 list_add(&copy[i].request->queuelist, &requests);
2058 continue;
2059 }
2060 merge_bio.head = copy[i].request->bio;
2061 merge_bio.tail = copy[i].request->biotail;
2062 bio_list_merge(&bio_list, &merge_bio);
2063 copy[i].request->bio = NULL;
2064 blk_end_request_all(copy[i].request, 0);
2065 }
2066
2067 kfree(copy);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002068 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002069 xenbus_switch_state(info->xbdev, XenbusStateConnected);
2070
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002071 /* Now safe for us to use the shared ring */
2072 info->connected = BLKIF_STATE_CONNECTED;
2073
Bob Liu3df0e502015-11-14 11:12:12 +08002074 for (r_index = 0; r_index < info->nr_rings; r_index++) {
2075 struct blkfront_ring_info *rinfo;
2076
2077 rinfo = &info->rinfo[r_index];
2078 /* Kick any other new requests queued since we resumed */
2079 kick_pending_request_queues(rinfo);
2080 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002081
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002082 list_for_each_entry_safe(req, n, &requests, queuelist) {
2083 /* Requeue pending requests (flush or discard) */
2084 list_del_init(&req->queuelist);
2085 BUG_ON(req->nr_phys_segments > segs);
Bob Liu907c3eb2015-07-13 17:55:24 +08002086 blk_mq_requeue_request(req);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002087 }
Bob Liu907c3eb2015-07-13 17:55:24 +08002088 blk_mq_kick_requeue_list(info->rq);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002089
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002090 while ((bio = bio_list_pop(&bio_list)) != NULL) {
2091 /* Traverse the list of pending bios and re-queue them */
2092 if (bio_segments(bio) > segs) {
2093 /*
2094 * This bio has more segments than what we can
2095 * handle, we have to split it.
2096 */
2097 pending = (bio_segments(bio) + segs - 1) / segs;
2098 split_bio = kzalloc(sizeof(*split_bio), GFP_NOIO);
2099 BUG_ON(split_bio == NULL);
2100 atomic_set(&split_bio->pending, pending);
2101 split_bio->bio = bio;
2102 for (i = 0; i < pending; i++) {
Julien Grallc004a6f2015-07-22 16:44:54 +01002103 offset = (i * segs * XEN_PAGE_SIZE) >> 9;
2104 size = min((unsigned int)(segs * XEN_PAGE_SIZE) >> 9,
Kent Overstreet4f024f32013-10-11 15:44:27 -07002105 (unsigned int)bio_sectors(bio) - offset);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002106 cloned_bio = bio_clone(bio, GFP_NOIO);
2107 BUG_ON(cloned_bio == NULL);
Kent Overstreet6678d832013-08-07 11:14:32 -07002108 bio_trim(cloned_bio, offset, size);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002109 cloned_bio->bi_private = split_bio;
2110 cloned_bio->bi_end_io = split_bio_end;
2111 submit_bio(cloned_bio->bi_rw, cloned_bio);
2112 }
2113 /*
2114 * Now we have to wait for all those smaller bios to
2115 * end, so we can also end the "parent" bio.
2116 */
2117 continue;
2118 }
2119 /* We don't need to split this bio */
2120 submit_bio(bio->bi_rw, bio);
2121 }
2122
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002123 return 0;
2124}
2125
2126/**
2127 * We are reconnecting to the backend, due to a suspend/resume, or a backend
2128 * driver restart. We tear down our blkif structure and recreate it, but
2129 * leave the device-layer structures intact so that this is transparent to the
2130 * rest of the kernel.
2131 */
2132static int blkfront_resume(struct xenbus_device *dev)
2133{
Greg Kroah-Hartmana1b4b122009-04-30 14:43:31 -07002134 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
Bob Liu3db70a82015-11-25 17:52:55 -05002135 int err = 0;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002136
2137 dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
2138
2139 blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
2140
Bob Liu3db70a82015-11-25 17:52:55 -05002141 err = negotiate_mq(info);
2142 if (err)
2143 return err;
2144
Ian Campbell203fd612009-12-04 15:33:54 +00002145 err = talk_to_blkback(dev, info);
Bob Liu2a6f71a2016-05-31 16:59:17 +08002146 if (!err)
2147 blk_mq_update_nr_hw_queues(&info->tag_set, info->nr_rings);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002148
2149 /*
2150 * We have to wait for the backend to switch to
2151 * connected state, since we want to read which
2152 * features it supports.
2153 */
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002154
2155 return err;
2156}
2157
Konrad Rzeszutek Wilk6f03a7f2015-11-16 15:14:41 -05002158static void blkfront_closing(struct blkfront_info *info)
Daniel Stoddenb70f5fa2010-04-30 22:01:19 +00002159{
2160 struct xenbus_device *xbdev = info->xbdev;
2161 struct block_device *bdev = NULL;
2162
2163 mutex_lock(&info->mutex);
2164
2165 if (xbdev->state == XenbusStateClosing) {
2166 mutex_unlock(&info->mutex);
2167 return;
2168 }
2169
2170 if (info->gd)
2171 bdev = bdget_disk(info->gd, 0);
2172
2173 mutex_unlock(&info->mutex);
2174
2175 if (!bdev) {
2176 xenbus_frontend_closed(xbdev);
2177 return;
2178 }
2179
2180 mutex_lock(&bdev->bd_mutex);
2181
Daniel Stodden7b32d102010-04-30 22:01:23 +00002182 if (bdev->bd_openers) {
Daniel Stoddenb70f5fa2010-04-30 22:01:19 +00002183 xenbus_dev_error(xbdev, -EBUSY,
2184 "Device in use; refusing to close");
2185 xenbus_switch_state(xbdev, XenbusStateClosing);
2186 } else {
2187 xlvbd_release_gendisk(info);
2188 xenbus_frontend_closed(xbdev);
2189 }
2190
2191 mutex_unlock(&bdev->bd_mutex);
2192 bdput(bdev);
2193}
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002194
Li Dongyanged30bf32011-09-01 18:39:09 +08002195static void blkfront_setup_discard(struct blkfront_info *info)
2196{
2197 int err;
Li Dongyanged30bf32011-09-01 18:39:09 +08002198 unsigned int discard_granularity;
2199 unsigned int discard_alignment;
Konrad Rzeszutek Wilk5ea42982011-10-12 16:23:30 -04002200 unsigned int discard_secure;
Li Dongyanged30bf32011-09-01 18:39:09 +08002201
Olaf Hering1c8cad62014-05-21 16:32:40 +02002202 info->feature_discard = 1;
2203 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2204 "discard-granularity", "%u", &discard_granularity,
2205 "discard-alignment", "%u", &discard_alignment,
2206 NULL);
2207 if (!err) {
2208 info->discard_granularity = discard_granularity;
2209 info->discard_alignment = discard_alignment;
2210 }
2211 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2212 "discard-secure", "%d", &discard_secure,
2213 NULL);
2214 if (!err)
2215 info->feature_secdiscard = !!discard_secure;
Li Dongyanged30bf32011-09-01 18:39:09 +08002216}
2217
Bob Liu81f35162015-11-14 11:12:11 +08002218static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002219{
Julien Grallc004a6f2015-07-22 16:44:54 +01002220 unsigned int psegs, grants;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002221 int err, i;
Bob Liu81f35162015-11-14 11:12:11 +08002222 struct blkfront_info *info = rinfo->dev_info;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002223
Julien Grall6cc568332015-08-13 13:13:35 +01002224 if (info->max_indirect_segments == 0) {
2225 if (!HAS_EXTRA_REQ)
2226 grants = BLKIF_MAX_SEGMENTS_PER_REQUEST;
2227 else {
2228 /*
2229 * When an extra req is required, the maximum
2230 * grants supported is related to the size of the
2231 * Linux block segment.
2232 */
2233 grants = GRANTS_PER_PSEG;
2234 }
2235 }
Bob Liud50babb2015-07-22 14:40:08 +08002236 else
Julien Grallc004a6f2015-07-22 16:44:54 +01002237 grants = info->max_indirect_segments;
2238 psegs = grants / GRANTS_PER_PSEG;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002239
Bob Liu81f35162015-11-14 11:12:11 +08002240 err = fill_grant_buffer(rinfo,
Julien Grallc004a6f2015-07-22 16:44:54 +01002241 (grants + INDIRECT_GREFS(grants)) * BLK_RING_SIZE(info));
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002242 if (err)
2243 goto out_of_memory;
2244
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01002245 if (!info->feature_persistent && info->max_indirect_segments) {
2246 /*
2247 * We are using indirect descriptors but not persistent
2248 * grants, we need to allocate a set of pages that can be
2249 * used for mapping indirect grefs
2250 */
Julien Grallc004a6f2015-07-22 16:44:54 +01002251 int num = INDIRECT_GREFS(grants) * BLK_RING_SIZE(info);
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01002252
Bob Liu81f35162015-11-14 11:12:11 +08002253 BUG_ON(!list_empty(&rinfo->indirect_pages));
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01002254 for (i = 0; i < num; i++) {
2255 struct page *indirect_page = alloc_page(GFP_NOIO);
2256 if (!indirect_page)
2257 goto out_of_memory;
Bob Liu81f35162015-11-14 11:12:11 +08002258 list_add(&indirect_page->lru, &rinfo->indirect_pages);
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01002259 }
2260 }
2261
Bob Liu86839c52015-06-03 13:40:03 +08002262 for (i = 0; i < BLK_RING_SIZE(info); i++) {
Bob Liu81f35162015-11-14 11:12:11 +08002263 rinfo->shadow[i].grants_used = kzalloc(
2264 sizeof(rinfo->shadow[i].grants_used[0]) * grants,
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002265 GFP_NOIO);
Bob Liu81f35162015-11-14 11:12:11 +08002266 rinfo->shadow[i].sg = kzalloc(sizeof(rinfo->shadow[i].sg[0]) * psegs, GFP_NOIO);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002267 if (info->max_indirect_segments)
Bob Liu81f35162015-11-14 11:12:11 +08002268 rinfo->shadow[i].indirect_grants = kzalloc(
2269 sizeof(rinfo->shadow[i].indirect_grants[0]) *
Julien Grallc004a6f2015-07-22 16:44:54 +01002270 INDIRECT_GREFS(grants),
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002271 GFP_NOIO);
Bob Liu81f35162015-11-14 11:12:11 +08002272 if ((rinfo->shadow[i].grants_used == NULL) ||
2273 (rinfo->shadow[i].sg == NULL) ||
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002274 (info->max_indirect_segments &&
Bob Liu81f35162015-11-14 11:12:11 +08002275 (rinfo->shadow[i].indirect_grants == NULL)))
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002276 goto out_of_memory;
Bob Liu81f35162015-11-14 11:12:11 +08002277 sg_init_table(rinfo->shadow[i].sg, psegs);
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002278 }
2279
2280
2281 return 0;
2282
2283out_of_memory:
Bob Liu86839c52015-06-03 13:40:03 +08002284 for (i = 0; i < BLK_RING_SIZE(info); i++) {
Bob Liu81f35162015-11-14 11:12:11 +08002285 kfree(rinfo->shadow[i].grants_used);
2286 rinfo->shadow[i].grants_used = NULL;
2287 kfree(rinfo->shadow[i].sg);
2288 rinfo->shadow[i].sg = NULL;
2289 kfree(rinfo->shadow[i].indirect_grants);
2290 rinfo->shadow[i].indirect_grants = NULL;
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002291 }
Bob Liu81f35162015-11-14 11:12:11 +08002292 if (!list_empty(&rinfo->indirect_pages)) {
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01002293 struct page *indirect_page, *n;
Bob Liu81f35162015-11-14 11:12:11 +08002294 list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
Roger Pau Monnebfe11d62013-10-29 18:31:14 +01002295 list_del(&indirect_page->lru);
2296 __free_page(indirect_page);
2297 }
2298 }
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002299 return -ENOMEM;
2300}
2301
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002302/*
Bob Liud50babb2015-07-22 14:40:08 +08002303 * Gather all backend feature-*
2304 */
Bob Liu3df0e502015-11-14 11:12:12 +08002305static void blkfront_gather_backend_features(struct blkfront_info *info)
Bob Liud50babb2015-07-22 14:40:08 +08002306{
2307 int err;
2308 int barrier, flush, discard, persistent;
2309 unsigned int indirect_segments;
2310
2311 info->feature_flush = 0;
2312
2313 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2314 "feature-barrier", "%d", &barrier,
2315 NULL);
2316
2317 /*
2318 * If there's no "feature-barrier" defined, then it means
2319 * we're dealing with a very old backend which writes
2320 * synchronously; nothing to do.
2321 *
2322 * If there are barriers, then we use flush.
2323 */
2324 if (!err && barrier)
2325 info->feature_flush = REQ_FLUSH | REQ_FUA;
2326 /*
2327 * And if there is "feature-flush-cache" use that above
2328 * barriers.
2329 */
2330 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2331 "feature-flush-cache", "%d", &flush,
2332 NULL);
2333
2334 if (!err && flush)
2335 info->feature_flush = REQ_FLUSH;
2336
2337 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2338 "feature-discard", "%d", &discard,
2339 NULL);
2340
2341 if (!err && discard)
2342 blkfront_setup_discard(info);
2343
2344 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2345 "feature-persistent", "%u", &persistent,
2346 NULL);
2347 if (err)
2348 info->feature_persistent = 0;
2349 else
2350 info->feature_persistent = persistent;
2351
2352 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2353 "feature-max-indirect-segments", "%u", &indirect_segments,
2354 NULL);
2355 if (err)
2356 info->max_indirect_segments = 0;
2357 else
2358 info->max_indirect_segments = min(indirect_segments,
2359 xen_blkif_max_segments);
Bob Liud50babb2015-07-22 14:40:08 +08002360}
2361
2362/*
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002363 * Invoked when the backend is finally 'ready' (and has told produced
2364 * the details about the physical device - #sectors, size, etc).
2365 */
2366static void blkfront_connect(struct blkfront_info *info)
2367{
2368 unsigned long long sectors;
2369 unsigned long sector_size;
Stefan Bader7c4d7d72013-05-13 16:28:15 +02002370 unsigned int physical_sector_size;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002371 unsigned int binfo;
Bob Liu3df0e502015-11-14 11:12:12 +08002372 int err, i;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002373
K. Y. Srinivasan1fa73be2010-03-11 13:42:26 -08002374 switch (info->connected) {
2375 case BLKIF_STATE_CONNECTED:
2376 /*
2377 * Potentially, the back-end may be signalling
2378 * a capacity change; update the capacity.
2379 */
2380 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
2381 "sectors", "%Lu", &sectors);
2382 if (XENBUS_EXIST_ERR(err))
2383 return;
2384 printk(KERN_INFO "Setting capacity to %Lu\n",
2385 sectors);
2386 set_capacity(info->gd, sectors);
K. Y. Srinivasan2def1412010-03-18 15:00:54 -07002387 revalidate_disk(info->gd);
K. Y. Srinivasan1fa73be2010-03-11 13:42:26 -08002388
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002389 return;
K. Y. Srinivasan1fa73be2010-03-11 13:42:26 -08002390 case BLKIF_STATE_SUSPENDED:
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002391 /*
2392 * If we are recovering from suspension, we need to wait
2393 * for the backend to announce it's features before
2394 * reconnecting, at least we need to know if the backend
2395 * supports indirect descriptors, and how many.
2396 */
2397 blkif_recover(info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002398 return;
2399
Jeremy Fitzhardingeb4dddb42010-03-11 15:10:40 -08002400 default:
2401 break;
K. Y. Srinivasan1fa73be2010-03-11 13:42:26 -08002402 }
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002403
2404 dev_dbg(&info->xbdev->dev, "%s:%s.\n",
2405 __func__, info->xbdev->otherend);
2406
2407 err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
2408 "sectors", "%llu", &sectors,
2409 "info", "%u", &binfo,
2410 "sector-size", "%lu", &sector_size,
2411 NULL);
2412 if (err) {
2413 xenbus_dev_fatal(info->xbdev, err,
2414 "reading backend fields at %s",
2415 info->xbdev->otherend);
2416 return;
2417 }
2418
Stefan Bader7c4d7d72013-05-13 16:28:15 +02002419 /*
2420 * physcial-sector-size is a newer field, so old backends may not
2421 * provide this. Assume physical sector size to be the same as
2422 * sector_size in that case.
2423 */
2424 err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
2425 "physical-sector-size", "%u", &physical_sector_size);
2426 if (err != 1)
2427 physical_sector_size = sector_size;
2428
Bob Liu3df0e502015-11-14 11:12:12 +08002429 blkfront_gather_backend_features(info);
2430 for (i = 0; i < info->nr_rings; i++) {
2431 err = blkfront_setup_indirect(&info->rinfo[i]);
2432 if (err) {
2433 xenbus_dev_fatal(info->xbdev, err, "setup_indirect at %s",
2434 info->xbdev->otherend);
2435 blkif_free(info, 0);
2436 break;
2437 }
Roger Pau Monne402b27f2013-04-18 16:06:54 +02002438 }
2439
Stefan Bader7c4d7d72013-05-13 16:28:15 +02002440 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size,
2441 physical_sector_size);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002442 if (err) {
2443 xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
2444 info->xbdev->otherend);
2445 return;
2446 }
2447
2448 xenbus_switch_state(info->xbdev, XenbusStateConnected);
2449
2450 /* Kick pending requests. */
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002451 info->connected = BLKIF_STATE_CONNECTED;
Bob Liu3df0e502015-11-14 11:12:12 +08002452 for (i = 0; i < info->nr_rings; i++)
2453 kick_pending_request_queues(&info->rinfo[i]);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002454
2455 add_disk(info->gd);
Christian Limpach1d78d702008-04-02 10:54:04 -07002456
2457 info->is_ready = 1;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002458}
2459
2460/**
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002461 * Callback received when the backend's state changes.
2462 */
Ian Campbell203fd612009-12-04 15:33:54 +00002463static void blkback_changed(struct xenbus_device *dev,
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002464 enum xenbus_state backend_state)
2465{
Greg Kroah-Hartmana1b4b122009-04-30 14:43:31 -07002466 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002467
Ian Campbell203fd612009-12-04 15:33:54 +00002468 dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002469
2470 switch (backend_state) {
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002471 case XenbusStateInitWait:
Bob Liua9b54bb2015-06-19 00:23:00 -04002472 if (dev->state != XenbusStateInitialising)
2473 break;
Konrad Rzeszutek Wilkc31ecf62015-12-18 16:28:53 -05002474 if (talk_to_blkback(dev, info))
Bob Liu8ab01442015-06-03 13:40:02 +08002475 break;
Bob Liu8ab01442015-06-03 13:40:02 +08002476 case XenbusStateInitialising:
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002477 case XenbusStateInitialised:
Noboru Iwamatsub78c9512009-10-13 17:22:29 -04002478 case XenbusStateReconfiguring:
2479 case XenbusStateReconfigured:
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002480 case XenbusStateUnknown:
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002481 break;
2482
2483 case XenbusStateConnected:
Bob Liuefd15352016-06-07 10:43:15 -04002484 /*
2485 * talk_to_blkback sets state to XenbusStateInitialised
2486 * and blkfront_connect sets it to XenbusStateConnected
2487 * (if connection went OK).
2488 *
2489 * If the backend (or toolstack) decides to poke at backend
2490 * state (and re-trigger the watch by setting the state repeatedly
2491 * to XenbusStateConnected (4)) we need to deal with this.
2492 * This is allowed as this is used to communicate to the guest
2493 * that the size of disk has changed!
2494 */
2495 if ((dev->state != XenbusStateInitialised) &&
2496 (dev->state != XenbusStateConnected)) {
Konrad Rzeszutek Wilkc31ecf62015-12-18 16:28:53 -05002497 if (talk_to_blkback(dev, info))
2498 break;
2499 }
Bob Liuefd15352016-06-07 10:43:15 -04002500
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002501 blkfront_connect(info);
2502 break;
2503
David Vrabel36613712014-02-04 18:53:56 +00002504 case XenbusStateClosed:
2505 if (dev->state == XenbusStateClosed)
2506 break;
2507 /* Missed the backend's Closing state -- fallthrough */
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002508 case XenbusStateClosing:
Cathy Averya54c8f02015-10-02 09:35:01 -04002509 if (info)
2510 blkfront_closing(info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002511 break;
2512 }
2513}
2514
Daniel Stoddenfa1bd352010-04-30 22:01:22 +00002515static int blkfront_remove(struct xenbus_device *xbdev)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002516{
Daniel Stoddenfa1bd352010-04-30 22:01:22 +00002517 struct blkfront_info *info = dev_get_drvdata(&xbdev->dev);
2518 struct block_device *bdev = NULL;
2519 struct gendisk *disk;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002520
Daniel Stoddenfa1bd352010-04-30 22:01:22 +00002521 dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002522
2523 blkif_free(info, 0);
2524
Daniel Stoddenfa1bd352010-04-30 22:01:22 +00002525 mutex_lock(&info->mutex);
2526
2527 disk = info->gd;
2528 if (disk)
2529 bdev = bdget_disk(disk, 0);
2530
2531 info->xbdev = NULL;
2532 mutex_unlock(&info->mutex);
2533
2534 if (!bdev) {
Jan Beulich0e345822010-08-07 18:28:55 +02002535 kfree(info);
Daniel Stoddenfa1bd352010-04-30 22:01:22 +00002536 return 0;
2537 }
2538
2539 /*
2540 * The xbdev was removed before we reached the Closed
2541 * state. See if it's safe to remove the disk. If the bdev
2542 * isn't closed yet, we let release take care of it.
2543 */
2544
2545 mutex_lock(&bdev->bd_mutex);
2546 info = disk->private_data;
2547
Daniel Stoddend54142c2010-08-07 18:51:21 +02002548 dev_warn(disk_to_dev(disk),
2549 "%s was hot-unplugged, %d stale handles\n",
2550 xbdev->nodename, bdev->bd_openers);
2551
Daniel Stodden7b32d102010-04-30 22:01:23 +00002552 if (info && !bdev->bd_openers) {
Daniel Stoddenfa1bd352010-04-30 22:01:22 +00002553 xlvbd_release_gendisk(info);
2554 disk->private_data = NULL;
2555 kfree(info);
2556 }
2557
2558 mutex_unlock(&bdev->bd_mutex);
2559 bdput(bdev);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002560
2561 return 0;
2562}
2563
Christian Limpach1d78d702008-04-02 10:54:04 -07002564static int blkfront_is_ready(struct xenbus_device *dev)
2565{
Greg Kroah-Hartmana1b4b122009-04-30 14:43:31 -07002566 struct blkfront_info *info = dev_get_drvdata(&dev->dev);
Christian Limpach1d78d702008-04-02 10:54:04 -07002567
Jan Beulich5d7ed202010-08-07 18:31:12 +02002568 return info->is_ready && info->xbdev;
Christian Limpach1d78d702008-04-02 10:54:04 -07002569}
2570
Al Viroa63c8482008-03-02 10:23:47 -05002571static int blkif_open(struct block_device *bdev, fmode_t mode)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002572{
Daniel Stodden13961742010-08-07 18:36:53 +02002573 struct gendisk *disk = bdev->bd_disk;
2574 struct blkfront_info *info;
2575 int err = 0;
Arnd Bergmann6e9624b2010-08-07 18:25:34 +02002576
Arnd Bergmann2a48fc02010-06-02 14:28:52 +02002577 mutex_lock(&blkfront_mutex);
Arnd Bergmann6e9624b2010-08-07 18:25:34 +02002578
Daniel Stodden13961742010-08-07 18:36:53 +02002579 info = disk->private_data;
2580 if (!info) {
2581 /* xbdev gone */
2582 err = -ERESTARTSYS;
2583 goto out;
2584 }
2585
2586 mutex_lock(&info->mutex);
2587
2588 if (!info->gd)
2589 /* xbdev is closed */
2590 err = -ERESTARTSYS;
2591
2592 mutex_unlock(&info->mutex);
2593
Daniel Stodden13961742010-08-07 18:36:53 +02002594out:
Arnd Bergmann2a48fc02010-06-02 14:28:52 +02002595 mutex_unlock(&blkfront_mutex);
Daniel Stodden13961742010-08-07 18:36:53 +02002596 return err;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002597}
2598
Al Virodb2a1442013-05-05 21:52:57 -04002599static void blkif_release(struct gendisk *disk, fmode_t mode)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002600{
Al Viroa63c8482008-03-02 10:23:47 -05002601 struct blkfront_info *info = disk->private_data;
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002602 struct block_device *bdev;
2603 struct xenbus_device *xbdev;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002604
Arnd Bergmann2a48fc02010-06-02 14:28:52 +02002605 mutex_lock(&blkfront_mutex);
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002606
2607 bdev = bdget_disk(disk, 0);
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002608
Felipe Pena2f089cb2013-11-09 13:36:09 -02002609 if (!bdev) {
2610 WARN(1, "Block device %s yanked out from us!\n", disk->disk_name);
2611 goto out_mutex;
2612 }
Daniel Stoddenacfca3c2010-08-07 18:47:26 +02002613 if (bdev->bd_openers)
2614 goto out;
2615
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002616 /*
2617 * Check if we have been instructed to close. We will have
2618 * deferred this request, because the bdev was still open.
2619 */
2620
2621 mutex_lock(&info->mutex);
2622 xbdev = info->xbdev;
2623
2624 if (xbdev && xbdev->state == XenbusStateClosing) {
2625 /* pending switch to state closed */
Daniel Stoddend54142c2010-08-07 18:51:21 +02002626 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002627 xlvbd_release_gendisk(info);
2628 xenbus_frontend_closed(info->xbdev);
2629 }
2630
2631 mutex_unlock(&info->mutex);
2632
2633 if (!xbdev) {
2634 /* sudden device removal */
Daniel Stoddend54142c2010-08-07 18:51:21 +02002635 dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002636 xlvbd_release_gendisk(info);
2637 disk->private_data = NULL;
2638 kfree(info);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002639 }
Daniel Stodden7fd152f2010-08-07 18:45:12 +02002640
Jens Axboea4cc14e2010-08-08 21:50:05 -04002641out:
Andrew Jonesdad5cf62012-02-16 13:16:25 +01002642 bdput(bdev);
Felipe Pena2f089cb2013-11-09 13:36:09 -02002643out_mutex:
Arnd Bergmann2a48fc02010-06-02 14:28:52 +02002644 mutex_unlock(&blkfront_mutex);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002645}
2646
Alexey Dobriyan83d5cde2009-09-21 17:01:13 -07002647static const struct block_device_operations xlvbd_block_fops =
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002648{
2649 .owner = THIS_MODULE,
Al Viroa63c8482008-03-02 10:23:47 -05002650 .open = blkif_open,
2651 .release = blkif_release,
Ian Campbell597592d2008-02-21 13:03:45 -08002652 .getgeo = blkif_getgeo,
Arnd Bergmann8a6cfeb2010-07-08 10:18:46 +02002653 .ioctl = blkif_ioctl,
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002654};
2655
2656
Márton Némethec9c42e2010-01-10 13:39:52 +01002657static const struct xenbus_device_id blkfront_ids[] = {
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002658 { "vbd" },
2659 { "" }
2660};
2661
David Vrabel95afae42014-09-08 17:30:41 +01002662static struct xenbus_driver blkfront_driver = {
2663 .ids = blkfront_ids,
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002664 .probe = blkfront_probe,
2665 .remove = blkfront_remove,
2666 .resume = blkfront_resume,
Ian Campbell203fd612009-12-04 15:33:54 +00002667 .otherend_changed = blkback_changed,
Christian Limpach1d78d702008-04-02 10:54:04 -07002668 .is_ready = blkfront_is_ready,
David Vrabel95afae42014-09-08 17:30:41 +01002669};
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002670
2671static int __init xlblk_init(void)
2672{
Laszlo Ersek469738e2011-10-07 21:34:38 +02002673 int ret;
Bob Liu28d949b2015-11-14 11:12:14 +08002674 int nr_cpus = num_online_cpus();
Laszlo Ersek469738e2011-10-07 21:34:38 +02002675
Jeremy Fitzhardinge6e833582008-08-19 13:16:17 -07002676 if (!xen_domain())
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002677 return -ENODEV;
2678
Julien Grall9cce2912015-10-13 17:50:11 +01002679 if (xen_blkif_max_ring_order > XENBUS_MAX_RING_GRANT_ORDER) {
Bob Liu86839c52015-06-03 13:40:03 +08002680 pr_info("Invalid max_ring_order (%d), will use default max: %d.\n",
Julien Grall9cce2912015-10-13 17:50:11 +01002681 xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER);
Peng Fan45fc8262015-11-25 18:26:01 +08002682 xen_blkif_max_ring_order = XENBUS_MAX_RING_GRANT_ORDER;
Bob Liu86839c52015-06-03 13:40:03 +08002683 }
2684
Bob Liu28d949b2015-11-14 11:12:14 +08002685 if (xen_blkif_max_queues > nr_cpus) {
2686 pr_info("Invalid max_queues (%d), will use default max: %d.\n",
2687 xen_blkif_max_queues, nr_cpus);
2688 xen_blkif_max_queues = nr_cpus;
2689 }
2690
Konrad Rzeszutek Wilk51c71a32013-11-26 15:05:40 -05002691 if (!xen_has_pv_disk_devices())
Igor Mammedovb9136d22012-03-21 15:08:38 +01002692 return -ENODEV;
2693
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002694 if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
2695 printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
2696 XENVBD_MAJOR, DEV_NAME);
2697 return -ENODEV;
2698 }
2699
Jan Beulich73db1442011-12-22 09:08:13 +00002700 ret = xenbus_register_frontend(&blkfront_driver);
Laszlo Ersek469738e2011-10-07 21:34:38 +02002701 if (ret) {
2702 unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
2703 return ret;
2704 }
2705
2706 return 0;
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002707}
2708module_init(xlblk_init);
2709
2710
Jan Beulich5a60d0c2008-06-17 10:47:08 +02002711static void __exit xlblk_exit(void)
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002712{
Jan Beulich86050672012-04-05 16:04:52 +01002713 xenbus_unregister_driver(&blkfront_driver);
2714 unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
2715 kfree(minors);
Jeremy Fitzhardinge9f27ee52007-07-17 18:37:06 -07002716}
2717module_exit(xlblk_exit);
2718
2719MODULE_DESCRIPTION("Xen virtual block device frontend");
2720MODULE_LICENSE("GPL");
2721MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
Mark McLoughlind2f0c522008-04-02 10:54:05 -07002722MODULE_ALIAS("xen:vbd");
Mark McLoughlin4f93f09b2008-04-02 10:54:06 -07002723MODULE_ALIAS("xenblk");