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1/*
2 * Copyright (C) 2003 Sistina Software
3 * Copyright (C) 2006 Red Hat GmbH
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm.h"
9
10#include <linux/device-mapper.h>
11
12#include <linux/bio.h>
13#include <linux/mempool.h>
14#include <linux/module.h>
15#include <linux/sched.h>
16#include <linux/slab.h>
17#include <linux/dm-io.h>
18
19#define DM_MSG_PREFIX "io"
20
21#define DM_IO_MAX_REGIONS BITS_PER_LONG
22#define MIN_IOS 16
23#define MIN_BIOS 16
24
25struct dm_io_client {
26 mempool_t *pool;
27 struct bio_set *bios;
28};
29
30/*
31 * Aligning 'struct io' reduces the number of bits required to store
32 * its address. Refer to store_io_and_region_in_bio() below.
33 */
34struct io {
35 unsigned long error_bits;
36 atomic_t count;
37 struct task_struct *sleeper;
38 struct dm_io_client *client;
39 io_notify_fn callback;
40 void *context;
41 void *vma_invalidate_address;
42 unsigned long vma_invalidate_size;
43} __attribute__((aligned(DM_IO_MAX_REGIONS)));
44
45static struct kmem_cache *_dm_io_cache;
46
47/*
48 * Create a client with mempool and bioset.
49 */
50struct dm_io_client *dm_io_client_create(void)
51{
52 struct dm_io_client *client;
53
54 client = kmalloc(sizeof(*client), GFP_KERNEL);
55 if (!client)
56 return ERR_PTR(-ENOMEM);
57
58 client->pool = mempool_create_slab_pool(MIN_IOS, _dm_io_cache);
59 if (!client->pool)
60 goto bad;
61
62 client->bios = bioset_create(MIN_BIOS, 0);
63 if (!client->bios)
64 goto bad;
65
66 return client;
67
68 bad:
69 if (client->pool)
70 mempool_destroy(client->pool);
71 kfree(client);
72 return ERR_PTR(-ENOMEM);
73}
74EXPORT_SYMBOL(dm_io_client_create);
75
76void dm_io_client_destroy(struct dm_io_client *client)
77{
78 mempool_destroy(client->pool);
79 bioset_free(client->bios);
80 kfree(client);
81}
82EXPORT_SYMBOL(dm_io_client_destroy);
83
84/*-----------------------------------------------------------------
85 * We need to keep track of which region a bio is doing io for.
86 * To avoid a memory allocation to store just 5 or 6 bits, we
87 * ensure the 'struct io' pointer is aligned so enough low bits are
88 * always zero and then combine it with the region number directly in
89 * bi_private.
90 *---------------------------------------------------------------*/
91static void store_io_and_region_in_bio(struct bio *bio, struct io *io,
92 unsigned region)
93{
94 if (unlikely(!IS_ALIGNED((unsigned long)io, DM_IO_MAX_REGIONS))) {
95 DMCRIT("Unaligned struct io pointer %p", io);
96 BUG();
97 }
98
99 bio->bi_private = (void *)((unsigned long)io | region);
100}
101
102static void retrieve_io_and_region_from_bio(struct bio *bio, struct io **io,
103 unsigned *region)
104{
105 unsigned long val = (unsigned long)bio->bi_private;
106
107 *io = (void *)(val & -(unsigned long)DM_IO_MAX_REGIONS);
108 *region = val & (DM_IO_MAX_REGIONS - 1);
109}
110
111/*-----------------------------------------------------------------
112 * We need an io object to keep track of the number of bios that
113 * have been dispatched for a particular io.
114 *---------------------------------------------------------------*/
115static void dec_count(struct io *io, unsigned int region, int error)
116{
117 if (error)
118 set_bit(region, &io->error_bits);
119
120 if (atomic_dec_and_test(&io->count)) {
121 if (io->vma_invalidate_size)
122 invalidate_kernel_vmap_range(io->vma_invalidate_address,
123 io->vma_invalidate_size);
124
125 if (io->sleeper)
126 wake_up_process(io->sleeper);
127
128 else {
129 unsigned long r = io->error_bits;
130 io_notify_fn fn = io->callback;
131 void *context = io->context;
132
133 mempool_free(io, io->client->pool);
134 fn(r, context);
135 }
136 }
137}
138
139static void endio(struct bio *bio, int error)
140{
141 struct io *io;
142 unsigned region;
143
144 if (error && bio_data_dir(bio) == READ)
145 zero_fill_bio(bio);
146
147 /*
148 * The bio destructor in bio_put() may use the io object.
149 */
150 retrieve_io_and_region_from_bio(bio, &io, ®ion);
151
152 bio_put(bio);
153
154 dec_count(io, region, error);
155}
156
157/*-----------------------------------------------------------------
158 * These little objects provide an abstraction for getting a new
159 * destination page for io.
160 *---------------------------------------------------------------*/
161struct dpages {
162 void (*get_page)(struct dpages *dp,
163 struct page **p, unsigned long *len, unsigned *offset);
164 void (*next_page)(struct dpages *dp);
165
166 unsigned context_u;
167 void *context_ptr;
168
169 void *vma_invalidate_address;
170 unsigned long vma_invalidate_size;
171};
172
173/*
174 * Functions for getting the pages from a list.
175 */
176static void list_get_page(struct dpages *dp,
177 struct page **p, unsigned long *len, unsigned *offset)
178{
179 unsigned o = dp->context_u;
180 struct page_list *pl = (struct page_list *) dp->context_ptr;
181
182 *p = pl->page;
183 *len = PAGE_SIZE - o;
184 *offset = o;
185}
186
187static void list_next_page(struct dpages *dp)
188{
189 struct page_list *pl = (struct page_list *) dp->context_ptr;
190 dp->context_ptr = pl->next;
191 dp->context_u = 0;
192}
193
194static void list_dp_init(struct dpages *dp, struct page_list *pl, unsigned offset)
195{
196 dp->get_page = list_get_page;
197 dp->next_page = list_next_page;
198 dp->context_u = offset;
199 dp->context_ptr = pl;
200}
201
202/*
203 * Functions for getting the pages from a bvec.
204 */
205static void bvec_get_page(struct dpages *dp,
206 struct page **p, unsigned long *len, unsigned *offset)
207{
208 struct bio_vec *bvec = (struct bio_vec *) dp->context_ptr;
209 *p = bvec->bv_page;
210 *len = bvec->bv_len;
211 *offset = bvec->bv_offset;
212}
213
214static void bvec_next_page(struct dpages *dp)
215{
216 struct bio_vec *bvec = (struct bio_vec *) dp->context_ptr;
217 dp->context_ptr = bvec + 1;
218}
219
220static void bvec_dp_init(struct dpages *dp, struct bio_vec *bvec)
221{
222 dp->get_page = bvec_get_page;
223 dp->next_page = bvec_next_page;
224 dp->context_ptr = bvec;
225}
226
227/*
228 * Functions for getting the pages from a VMA.
229 */
230static void vm_get_page(struct dpages *dp,
231 struct page **p, unsigned long *len, unsigned *offset)
232{
233 *p = vmalloc_to_page(dp->context_ptr);
234 *offset = dp->context_u;
235 *len = PAGE_SIZE - dp->context_u;
236}
237
238static void vm_next_page(struct dpages *dp)
239{
240 dp->context_ptr += PAGE_SIZE - dp->context_u;
241 dp->context_u = 0;
242}
243
244static void vm_dp_init(struct dpages *dp, void *data)
245{
246 dp->get_page = vm_get_page;
247 dp->next_page = vm_next_page;
248 dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
249 dp->context_ptr = data;
250}
251
252static void dm_bio_destructor(struct bio *bio)
253{
254 unsigned region;
255 struct io *io;
256
257 retrieve_io_and_region_from_bio(bio, &io, ®ion);
258
259 bio_free(bio, io->client->bios);
260}
261
262/*
263 * Functions for getting the pages from kernel memory.
264 */
265static void km_get_page(struct dpages *dp, struct page **p, unsigned long *len,
266 unsigned *offset)
267{
268 *p = virt_to_page(dp->context_ptr);
269 *offset = dp->context_u;
270 *len = PAGE_SIZE - dp->context_u;
271}
272
273static void km_next_page(struct dpages *dp)
274{
275 dp->context_ptr += PAGE_SIZE - dp->context_u;
276 dp->context_u = 0;
277}
278
279static void km_dp_init(struct dpages *dp, void *data)
280{
281 dp->get_page = km_get_page;
282 dp->next_page = km_next_page;
283 dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
284 dp->context_ptr = data;
285}
286
287/*-----------------------------------------------------------------
288 * IO routines that accept a list of pages.
289 *---------------------------------------------------------------*/
290static void do_region(int rw, unsigned region, struct dm_io_region *where,
291 struct dpages *dp, struct io *io)
292{
293 struct bio *bio;
294 struct page *page;
295 unsigned long len;
296 unsigned offset;
297 unsigned num_bvecs;
298 sector_t remaining = where->count;
299
300 /*
301 * where->count may be zero if rw holds a flush and we need to
302 * send a zero-sized flush.
303 */
304 do {
305 /*
306 * Allocate a suitably sized-bio.
307 */
308 num_bvecs = dm_sector_div_up(remaining,
309 (PAGE_SIZE >> SECTOR_SHIFT));
310 num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev), num_bvecs);
311 bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios);
312 bio->bi_sector = where->sector + (where->count - remaining);
313 bio->bi_bdev = where->bdev;
314 bio->bi_end_io = endio;
315 bio->bi_destructor = dm_bio_destructor;
316 store_io_and_region_in_bio(bio, io, region);
317
318 /*
319 * Try and add as many pages as possible.
320 */
321 while (remaining) {
322 dp->get_page(dp, &page, &len, &offset);
323 len = min(len, to_bytes(remaining));
324 if (!bio_add_page(bio, page, len, offset))
325 break;
326
327 offset = 0;
328 remaining -= to_sector(len);
329 dp->next_page(dp);
330 }
331
332 atomic_inc(&io->count);
333 submit_bio(rw, bio);
334 } while (remaining);
335}
336
337static void dispatch_io(int rw, unsigned int num_regions,
338 struct dm_io_region *where, struct dpages *dp,
339 struct io *io, int sync)
340{
341 int i;
342 struct dpages old_pages = *dp;
343
344 BUG_ON(num_regions > DM_IO_MAX_REGIONS);
345
346 if (sync)
347 rw |= REQ_SYNC;
348
349 /*
350 * For multiple regions we need to be careful to rewind
351 * the dp object for each call to do_region.
352 */
353 for (i = 0; i < num_regions; i++) {
354 *dp = old_pages;
355 if (where[i].count || (rw & REQ_FLUSH))
356 do_region(rw, i, where + i, dp, io);
357 }
358
359 /*
360 * Drop the extra reference that we were holding to avoid
361 * the io being completed too early.
362 */
363 dec_count(io, 0, 0);
364}
365
366static int sync_io(struct dm_io_client *client, unsigned int num_regions,
367 struct dm_io_region *where, int rw, struct dpages *dp,
368 unsigned long *error_bits)
369{
370 /*
371 * gcc <= 4.3 can't do the alignment for stack variables, so we must
372 * align it on our own.
373 * volatile prevents the optimizer from removing or reusing
374 * "io_" field from the stack frame (allowed in ANSI C).
375 */
376 volatile char io_[sizeof(struct io) + __alignof__(struct io) - 1];
377 struct io *io = (struct io *)PTR_ALIGN(&io_, __alignof__(struct io));
378
379 if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
380 WARN_ON(1);
381 return -EIO;
382 }
383
384 io->error_bits = 0;
385 atomic_set(&io->count, 1); /* see dispatch_io() */
386 io->sleeper = current;
387 io->client = client;
388
389 io->vma_invalidate_address = dp->vma_invalidate_address;
390 io->vma_invalidate_size = dp->vma_invalidate_size;
391
392 dispatch_io(rw, num_regions, where, dp, io, 1);
393
394 while (1) {
395 set_current_state(TASK_UNINTERRUPTIBLE);
396
397 if (!atomic_read(&io->count))
398 break;
399
400 io_schedule();
401 }
402 set_current_state(TASK_RUNNING);
403
404 if (error_bits)
405 *error_bits = io->error_bits;
406
407 return io->error_bits ? -EIO : 0;
408}
409
410static int async_io(struct dm_io_client *client, unsigned int num_regions,
411 struct dm_io_region *where, int rw, struct dpages *dp,
412 io_notify_fn fn, void *context)
413{
414 struct io *io;
415
416 if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
417 WARN_ON(1);
418 fn(1, context);
419 return -EIO;
420 }
421
422 io = mempool_alloc(client->pool, GFP_NOIO);
423 io->error_bits = 0;
424 atomic_set(&io->count, 1); /* see dispatch_io() */
425 io->sleeper = NULL;
426 io->client = client;
427 io->callback = fn;
428 io->context = context;
429
430 io->vma_invalidate_address = dp->vma_invalidate_address;
431 io->vma_invalidate_size = dp->vma_invalidate_size;
432
433 dispatch_io(rw, num_regions, where, dp, io, 0);
434 return 0;
435}
436
437static int dp_init(struct dm_io_request *io_req, struct dpages *dp,
438 unsigned long size)
439{
440 /* Set up dpages based on memory type */
441
442 dp->vma_invalidate_address = NULL;
443 dp->vma_invalidate_size = 0;
444
445 switch (io_req->mem.type) {
446 case DM_IO_PAGE_LIST:
447 list_dp_init(dp, io_req->mem.ptr.pl, io_req->mem.offset);
448 break;
449
450 case DM_IO_BVEC:
451 bvec_dp_init(dp, io_req->mem.ptr.bvec);
452 break;
453
454 case DM_IO_VMA:
455 flush_kernel_vmap_range(io_req->mem.ptr.vma, size);
456 if ((io_req->bi_rw & RW_MASK) == READ) {
457 dp->vma_invalidate_address = io_req->mem.ptr.vma;
458 dp->vma_invalidate_size = size;
459 }
460 vm_dp_init(dp, io_req->mem.ptr.vma);
461 break;
462
463 case DM_IO_KMEM:
464 km_dp_init(dp, io_req->mem.ptr.addr);
465 break;
466
467 default:
468 return -EINVAL;
469 }
470
471 return 0;
472}
473
474/*
475 * New collapsed (a)synchronous interface.
476 *
477 * If the IO is asynchronous (i.e. it has notify.fn), you must either unplug
478 * the queue with blk_unplug() some time later or set REQ_SYNC in
479io_req->bi_rw. If you fail to do one of these, the IO will be submitted to
480 * the disk after q->unplug_delay, which defaults to 3ms in blk-settings.c.
481 */
482int dm_io(struct dm_io_request *io_req, unsigned num_regions,
483 struct dm_io_region *where, unsigned long *sync_error_bits)
484{
485 int r;
486 struct dpages dp;
487
488 r = dp_init(io_req, &dp, (unsigned long)where->count << SECTOR_SHIFT);
489 if (r)
490 return r;
491
492 if (!io_req->notify.fn)
493 return sync_io(io_req->client, num_regions, where,
494 io_req->bi_rw, &dp, sync_error_bits);
495
496 return async_io(io_req->client, num_regions, where, io_req->bi_rw,
497 &dp, io_req->notify.fn, io_req->notify.context);
498}
499EXPORT_SYMBOL(dm_io);
500
501int __init dm_io_init(void)
502{
503 _dm_io_cache = KMEM_CACHE(io, 0);
504 if (!_dm_io_cache)
505 return -ENOMEM;
506
507 return 0;
508}
509
510void dm_io_exit(void)
511{
512 kmem_cache_destroy(_dm_io_cache);
513 _dm_io_cache = NULL;
514}
1/*
2 * Copyright (C) 2003 Sistina Software
3 * Copyright (C) 2006 Red Hat GmbH
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm.h"
9
10#include <linux/device-mapper.h>
11
12#include <linux/bio.h>
13#include <linux/completion.h>
14#include <linux/mempool.h>
15#include <linux/module.h>
16#include <linux/sched.h>
17#include <linux/slab.h>
18#include <linux/dm-io.h>
19
20#define DM_MSG_PREFIX "io"
21
22#define DM_IO_MAX_REGIONS BITS_PER_LONG
23
24struct dm_io_client {
25 mempool_t *pool;
26 struct bio_set *bios;
27};
28
29/*
30 * Aligning 'struct io' reduces the number of bits required to store
31 * its address. Refer to store_io_and_region_in_bio() below.
32 */
33struct io {
34 unsigned long error_bits;
35 atomic_t count;
36 struct dm_io_client *client;
37 io_notify_fn callback;
38 void *context;
39 void *vma_invalidate_address;
40 unsigned long vma_invalidate_size;
41} __attribute__((aligned(DM_IO_MAX_REGIONS)));
42
43static struct kmem_cache *_dm_io_cache;
44
45/*
46 * Create a client with mempool and bioset.
47 */
48struct dm_io_client *dm_io_client_create(void)
49{
50 struct dm_io_client *client;
51 unsigned min_ios = dm_get_reserved_bio_based_ios();
52
53 client = kmalloc(sizeof(*client), GFP_KERNEL);
54 if (!client)
55 return ERR_PTR(-ENOMEM);
56
57 client->pool = mempool_create_slab_pool(min_ios, _dm_io_cache);
58 if (!client->pool)
59 goto bad;
60
61 client->bios = bioset_create(min_ios, 0);
62 if (!client->bios)
63 goto bad;
64
65 return client;
66
67 bad:
68 mempool_destroy(client->pool);
69 kfree(client);
70 return ERR_PTR(-ENOMEM);
71}
72EXPORT_SYMBOL(dm_io_client_create);
73
74void dm_io_client_destroy(struct dm_io_client *client)
75{
76 mempool_destroy(client->pool);
77 bioset_free(client->bios);
78 kfree(client);
79}
80EXPORT_SYMBOL(dm_io_client_destroy);
81
82/*-----------------------------------------------------------------
83 * We need to keep track of which region a bio is doing io for.
84 * To avoid a memory allocation to store just 5 or 6 bits, we
85 * ensure the 'struct io' pointer is aligned so enough low bits are
86 * always zero and then combine it with the region number directly in
87 * bi_private.
88 *---------------------------------------------------------------*/
89static void store_io_and_region_in_bio(struct bio *bio, struct io *io,
90 unsigned region)
91{
92 if (unlikely(!IS_ALIGNED((unsigned long)io, DM_IO_MAX_REGIONS))) {
93 DMCRIT("Unaligned struct io pointer %p", io);
94 BUG();
95 }
96
97 bio->bi_private = (void *)((unsigned long)io | region);
98}
99
100static void retrieve_io_and_region_from_bio(struct bio *bio, struct io **io,
101 unsigned *region)
102{
103 unsigned long val = (unsigned long)bio->bi_private;
104
105 *io = (void *)(val & -(unsigned long)DM_IO_MAX_REGIONS);
106 *region = val & (DM_IO_MAX_REGIONS - 1);
107}
108
109/*-----------------------------------------------------------------
110 * We need an io object to keep track of the number of bios that
111 * have been dispatched for a particular io.
112 *---------------------------------------------------------------*/
113static void complete_io(struct io *io)
114{
115 unsigned long error_bits = io->error_bits;
116 io_notify_fn fn = io->callback;
117 void *context = io->context;
118
119 if (io->vma_invalidate_size)
120 invalidate_kernel_vmap_range(io->vma_invalidate_address,
121 io->vma_invalidate_size);
122
123 mempool_free(io, io->client->pool);
124 fn(error_bits, context);
125}
126
127static void dec_count(struct io *io, unsigned int region, int error)
128{
129 if (error)
130 set_bit(region, &io->error_bits);
131
132 if (atomic_dec_and_test(&io->count))
133 complete_io(io);
134}
135
136static void endio(struct bio *bio)
137{
138 struct io *io;
139 unsigned region;
140 int error;
141
142 if (bio->bi_error && bio_data_dir(bio) == READ)
143 zero_fill_bio(bio);
144
145 /*
146 * The bio destructor in bio_put() may use the io object.
147 */
148 retrieve_io_and_region_from_bio(bio, &io, ®ion);
149
150 error = bio->bi_error;
151 bio_put(bio);
152
153 dec_count(io, region, error);
154}
155
156/*-----------------------------------------------------------------
157 * These little objects provide an abstraction for getting a new
158 * destination page for io.
159 *---------------------------------------------------------------*/
160struct dpages {
161 void (*get_page)(struct dpages *dp,
162 struct page **p, unsigned long *len, unsigned *offset);
163 void (*next_page)(struct dpages *dp);
164
165 unsigned context_u;
166 void *context_ptr;
167
168 void *vma_invalidate_address;
169 unsigned long vma_invalidate_size;
170};
171
172/*
173 * Functions for getting the pages from a list.
174 */
175static void list_get_page(struct dpages *dp,
176 struct page **p, unsigned long *len, unsigned *offset)
177{
178 unsigned o = dp->context_u;
179 struct page_list *pl = (struct page_list *) dp->context_ptr;
180
181 *p = pl->page;
182 *len = PAGE_SIZE - o;
183 *offset = o;
184}
185
186static void list_next_page(struct dpages *dp)
187{
188 struct page_list *pl = (struct page_list *) dp->context_ptr;
189 dp->context_ptr = pl->next;
190 dp->context_u = 0;
191}
192
193static void list_dp_init(struct dpages *dp, struct page_list *pl, unsigned offset)
194{
195 dp->get_page = list_get_page;
196 dp->next_page = list_next_page;
197 dp->context_u = offset;
198 dp->context_ptr = pl;
199}
200
201/*
202 * Functions for getting the pages from a bvec.
203 */
204static void bio_get_page(struct dpages *dp, struct page **p,
205 unsigned long *len, unsigned *offset)
206{
207 struct bio_vec *bvec = dp->context_ptr;
208 *p = bvec->bv_page;
209 *len = bvec->bv_len - dp->context_u;
210 *offset = bvec->bv_offset + dp->context_u;
211}
212
213static void bio_next_page(struct dpages *dp)
214{
215 struct bio_vec *bvec = dp->context_ptr;
216 dp->context_ptr = bvec + 1;
217 dp->context_u = 0;
218}
219
220static void bio_dp_init(struct dpages *dp, struct bio *bio)
221{
222 dp->get_page = bio_get_page;
223 dp->next_page = bio_next_page;
224 dp->context_ptr = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
225 dp->context_u = bio->bi_iter.bi_bvec_done;
226}
227
228/*
229 * Functions for getting the pages from a VMA.
230 */
231static void vm_get_page(struct dpages *dp,
232 struct page **p, unsigned long *len, unsigned *offset)
233{
234 *p = vmalloc_to_page(dp->context_ptr);
235 *offset = dp->context_u;
236 *len = PAGE_SIZE - dp->context_u;
237}
238
239static void vm_next_page(struct dpages *dp)
240{
241 dp->context_ptr += PAGE_SIZE - dp->context_u;
242 dp->context_u = 0;
243}
244
245static void vm_dp_init(struct dpages *dp, void *data)
246{
247 dp->get_page = vm_get_page;
248 dp->next_page = vm_next_page;
249 dp->context_u = offset_in_page(data);
250 dp->context_ptr = data;
251}
252
253/*
254 * Functions for getting the pages from kernel memory.
255 */
256static void km_get_page(struct dpages *dp, struct page **p, unsigned long *len,
257 unsigned *offset)
258{
259 *p = virt_to_page(dp->context_ptr);
260 *offset = dp->context_u;
261 *len = PAGE_SIZE - dp->context_u;
262}
263
264static void km_next_page(struct dpages *dp)
265{
266 dp->context_ptr += PAGE_SIZE - dp->context_u;
267 dp->context_u = 0;
268}
269
270static void km_dp_init(struct dpages *dp, void *data)
271{
272 dp->get_page = km_get_page;
273 dp->next_page = km_next_page;
274 dp->context_u = offset_in_page(data);
275 dp->context_ptr = data;
276}
277
278/*-----------------------------------------------------------------
279 * IO routines that accept a list of pages.
280 *---------------------------------------------------------------*/
281static void do_region(int rw, unsigned region, struct dm_io_region *where,
282 struct dpages *dp, struct io *io)
283{
284 struct bio *bio;
285 struct page *page;
286 unsigned long len;
287 unsigned offset;
288 unsigned num_bvecs;
289 sector_t remaining = where->count;
290 struct request_queue *q = bdev_get_queue(where->bdev);
291 unsigned short logical_block_size = queue_logical_block_size(q);
292 sector_t num_sectors;
293 unsigned int uninitialized_var(special_cmd_max_sectors);
294
295 /*
296 * Reject unsupported discard and write same requests.
297 */
298 if (rw & REQ_DISCARD)
299 special_cmd_max_sectors = q->limits.max_discard_sectors;
300 else if (rw & REQ_WRITE_SAME)
301 special_cmd_max_sectors = q->limits.max_write_same_sectors;
302 if ((rw & (REQ_DISCARD | REQ_WRITE_SAME)) && special_cmd_max_sectors == 0) {
303 dec_count(io, region, -EOPNOTSUPP);
304 return;
305 }
306
307 /*
308 * where->count may be zero if rw holds a flush and we need to
309 * send a zero-sized flush.
310 */
311 do {
312 /*
313 * Allocate a suitably sized-bio.
314 */
315 if ((rw & REQ_DISCARD) || (rw & REQ_WRITE_SAME))
316 num_bvecs = 1;
317 else
318 num_bvecs = min_t(int, BIO_MAX_PAGES,
319 dm_sector_div_up(remaining, (PAGE_SIZE >> SECTOR_SHIFT)));
320
321 bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios);
322 bio->bi_iter.bi_sector = where->sector + (where->count - remaining);
323 bio->bi_bdev = where->bdev;
324 bio->bi_end_io = endio;
325 store_io_and_region_in_bio(bio, io, region);
326
327 if (rw & REQ_DISCARD) {
328 num_sectors = min_t(sector_t, special_cmd_max_sectors, remaining);
329 bio->bi_iter.bi_size = num_sectors << SECTOR_SHIFT;
330 remaining -= num_sectors;
331 } else if (rw & REQ_WRITE_SAME) {
332 /*
333 * WRITE SAME only uses a single page.
334 */
335 dp->get_page(dp, &page, &len, &offset);
336 bio_add_page(bio, page, logical_block_size, offset);
337 num_sectors = min_t(sector_t, special_cmd_max_sectors, remaining);
338 bio->bi_iter.bi_size = num_sectors << SECTOR_SHIFT;
339
340 offset = 0;
341 remaining -= num_sectors;
342 dp->next_page(dp);
343 } else while (remaining) {
344 /*
345 * Try and add as many pages as possible.
346 */
347 dp->get_page(dp, &page, &len, &offset);
348 len = min(len, to_bytes(remaining));
349 if (!bio_add_page(bio, page, len, offset))
350 break;
351
352 offset = 0;
353 remaining -= to_sector(len);
354 dp->next_page(dp);
355 }
356
357 atomic_inc(&io->count);
358 submit_bio(rw, bio);
359 } while (remaining);
360}
361
362static void dispatch_io(int rw, unsigned int num_regions,
363 struct dm_io_region *where, struct dpages *dp,
364 struct io *io, int sync)
365{
366 int i;
367 struct dpages old_pages = *dp;
368
369 BUG_ON(num_regions > DM_IO_MAX_REGIONS);
370
371 if (sync)
372 rw |= REQ_SYNC;
373
374 /*
375 * For multiple regions we need to be careful to rewind
376 * the dp object for each call to do_region.
377 */
378 for (i = 0; i < num_regions; i++) {
379 *dp = old_pages;
380 if (where[i].count || (rw & REQ_FLUSH))
381 do_region(rw, i, where + i, dp, io);
382 }
383
384 /*
385 * Drop the extra reference that we were holding to avoid
386 * the io being completed too early.
387 */
388 dec_count(io, 0, 0);
389}
390
391struct sync_io {
392 unsigned long error_bits;
393 struct completion wait;
394};
395
396static void sync_io_complete(unsigned long error, void *context)
397{
398 struct sync_io *sio = context;
399
400 sio->error_bits = error;
401 complete(&sio->wait);
402}
403
404static int sync_io(struct dm_io_client *client, unsigned int num_regions,
405 struct dm_io_region *where, int rw, struct dpages *dp,
406 unsigned long *error_bits)
407{
408 struct io *io;
409 struct sync_io sio;
410
411 if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
412 WARN_ON(1);
413 return -EIO;
414 }
415
416 init_completion(&sio.wait);
417
418 io = mempool_alloc(client->pool, GFP_NOIO);
419 io->error_bits = 0;
420 atomic_set(&io->count, 1); /* see dispatch_io() */
421 io->client = client;
422 io->callback = sync_io_complete;
423 io->context = &sio;
424
425 io->vma_invalidate_address = dp->vma_invalidate_address;
426 io->vma_invalidate_size = dp->vma_invalidate_size;
427
428 dispatch_io(rw, num_regions, where, dp, io, 1);
429
430 wait_for_completion_io(&sio.wait);
431
432 if (error_bits)
433 *error_bits = sio.error_bits;
434
435 return sio.error_bits ? -EIO : 0;
436}
437
438static int async_io(struct dm_io_client *client, unsigned int num_regions,
439 struct dm_io_region *where, int rw, struct dpages *dp,
440 io_notify_fn fn, void *context)
441{
442 struct io *io;
443
444 if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
445 WARN_ON(1);
446 fn(1, context);
447 return -EIO;
448 }
449
450 io = mempool_alloc(client->pool, GFP_NOIO);
451 io->error_bits = 0;
452 atomic_set(&io->count, 1); /* see dispatch_io() */
453 io->client = client;
454 io->callback = fn;
455 io->context = context;
456
457 io->vma_invalidate_address = dp->vma_invalidate_address;
458 io->vma_invalidate_size = dp->vma_invalidate_size;
459
460 dispatch_io(rw, num_regions, where, dp, io, 0);
461 return 0;
462}
463
464static int dp_init(struct dm_io_request *io_req, struct dpages *dp,
465 unsigned long size)
466{
467 /* Set up dpages based on memory type */
468
469 dp->vma_invalidate_address = NULL;
470 dp->vma_invalidate_size = 0;
471
472 switch (io_req->mem.type) {
473 case DM_IO_PAGE_LIST:
474 list_dp_init(dp, io_req->mem.ptr.pl, io_req->mem.offset);
475 break;
476
477 case DM_IO_BIO:
478 bio_dp_init(dp, io_req->mem.ptr.bio);
479 break;
480
481 case DM_IO_VMA:
482 flush_kernel_vmap_range(io_req->mem.ptr.vma, size);
483 if ((io_req->bi_rw & RW_MASK) == READ) {
484 dp->vma_invalidate_address = io_req->mem.ptr.vma;
485 dp->vma_invalidate_size = size;
486 }
487 vm_dp_init(dp, io_req->mem.ptr.vma);
488 break;
489
490 case DM_IO_KMEM:
491 km_dp_init(dp, io_req->mem.ptr.addr);
492 break;
493
494 default:
495 return -EINVAL;
496 }
497
498 return 0;
499}
500
501/*
502 * New collapsed (a)synchronous interface.
503 *
504 * If the IO is asynchronous (i.e. it has notify.fn), you must either unplug
505 * the queue with blk_unplug() some time later or set REQ_SYNC in io_req->bi_rw.
506 * If you fail to do one of these, the IO will be submitted to the disk after
507 * q->unplug_delay, which defaults to 3ms in blk-settings.c.
508 */
509int dm_io(struct dm_io_request *io_req, unsigned num_regions,
510 struct dm_io_region *where, unsigned long *sync_error_bits)
511{
512 int r;
513 struct dpages dp;
514
515 r = dp_init(io_req, &dp, (unsigned long)where->count << SECTOR_SHIFT);
516 if (r)
517 return r;
518
519 if (!io_req->notify.fn)
520 return sync_io(io_req->client, num_regions, where,
521 io_req->bi_rw, &dp, sync_error_bits);
522
523 return async_io(io_req->client, num_regions, where, io_req->bi_rw,
524 &dp, io_req->notify.fn, io_req->notify.context);
525}
526EXPORT_SYMBOL(dm_io);
527
528int __init dm_io_init(void)
529{
530 _dm_io_cache = KMEM_CACHE(io, 0);
531 if (!_dm_io_cache)
532 return -ENOMEM;
533
534 return 0;
535}
536
537void dm_io_exit(void)
538{
539 kmem_cache_destroy(_dm_io_cache);
540 _dm_io_cache = NULL;
541}