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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/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}
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-core.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 int ret;
53
54 client = kzalloc(sizeof(*client), GFP_KERNEL);
55 if (!client)
56 return ERR_PTR(-ENOMEM);
57
58 ret = mempool_init_slab_pool(&client->pool, min_ios, _dm_io_cache);
59 if (ret)
60 goto bad;
61
62 ret = bioset_init(&client->bios, min_ios, 0, BIOSET_NEED_BVECS);
63 if (ret)
64 goto bad;
65
66 return client;
67
68 bad:
69 mempool_exit(&client->pool);
70 kfree(client);
71 return ERR_PTR(ret);
72}
73EXPORT_SYMBOL(dm_io_client_create);
74
75void dm_io_client_destroy(struct dm_io_client *client)
76{
77 mempool_exit(&client->pool);
78 bioset_exit(&client->bios);
79 kfree(client);
80}
81EXPORT_SYMBOL(dm_io_client_destroy);
82
83/*-----------------------------------------------------------------
84 * We need to keep track of which region a bio is doing io for.
85 * To avoid a memory allocation to store just 5 or 6 bits, we
86 * ensure the 'struct io' pointer is aligned so enough low bits are
87 * always zero and then combine it with the region number directly in
88 * bi_private.
89 *---------------------------------------------------------------*/
90static void store_io_and_region_in_bio(struct bio *bio, struct io *io,
91 unsigned region)
92{
93 if (unlikely(!IS_ALIGNED((unsigned long)io, DM_IO_MAX_REGIONS))) {
94 DMCRIT("Unaligned struct io pointer %p", io);
95 BUG();
96 }
97
98 bio->bi_private = (void *)((unsigned long)io | region);
99}
100
101static void retrieve_io_and_region_from_bio(struct bio *bio, struct io **io,
102 unsigned *region)
103{
104 unsigned long val = (unsigned long)bio->bi_private;
105
106 *io = (void *)(val & -(unsigned long)DM_IO_MAX_REGIONS);
107 *region = val & (DM_IO_MAX_REGIONS - 1);
108}
109
110/*-----------------------------------------------------------------
111 * We need an io object to keep track of the number of bios that
112 * have been dispatched for a particular io.
113 *---------------------------------------------------------------*/
114static void complete_io(struct io *io)
115{
116 unsigned long error_bits = io->error_bits;
117 io_notify_fn fn = io->callback;
118 void *context = io->context;
119
120 if (io->vma_invalidate_size)
121 invalidate_kernel_vmap_range(io->vma_invalidate_address,
122 io->vma_invalidate_size);
123
124 mempool_free(io, &io->client->pool);
125 fn(error_bits, context);
126}
127
128static void dec_count(struct io *io, unsigned int region, blk_status_t error)
129{
130 if (error)
131 set_bit(region, &io->error_bits);
132
133 if (atomic_dec_and_test(&io->count))
134 complete_io(io);
135}
136
137static void endio(struct bio *bio)
138{
139 struct io *io;
140 unsigned region;
141 blk_status_t error;
142
143 if (bio->bi_status && bio_data_dir(bio) == READ)
144 zero_fill_bio(bio);
145
146 /*
147 * The bio destructor in bio_put() may use the io object.
148 */
149 retrieve_io_and_region_from_bio(bio, &io, ®ion);
150
151 error = bio->bi_status;
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 union {
167 unsigned context_u;
168 struct bvec_iter context_bi;
169 };
170 void *context_ptr;
171
172 void *vma_invalidate_address;
173 unsigned long vma_invalidate_size;
174};
175
176/*
177 * Functions for getting the pages from a list.
178 */
179static void list_get_page(struct dpages *dp,
180 struct page **p, unsigned long *len, unsigned *offset)
181{
182 unsigned o = dp->context_u;
183 struct page_list *pl = (struct page_list *) dp->context_ptr;
184
185 *p = pl->page;
186 *len = PAGE_SIZE - o;
187 *offset = o;
188}
189
190static void list_next_page(struct dpages *dp)
191{
192 struct page_list *pl = (struct page_list *) dp->context_ptr;
193 dp->context_ptr = pl->next;
194 dp->context_u = 0;
195}
196
197static void list_dp_init(struct dpages *dp, struct page_list *pl, unsigned offset)
198{
199 dp->get_page = list_get_page;
200 dp->next_page = list_next_page;
201 dp->context_u = offset;
202 dp->context_ptr = pl;
203}
204
205/*
206 * Functions for getting the pages from a bvec.
207 */
208static void bio_get_page(struct dpages *dp, struct page **p,
209 unsigned long *len, unsigned *offset)
210{
211 struct bio_vec bvec = bvec_iter_bvec((struct bio_vec *)dp->context_ptr,
212 dp->context_bi);
213
214 *p = bvec.bv_page;
215 *len = bvec.bv_len;
216 *offset = bvec.bv_offset;
217
218 /* avoid figuring it out again in bio_next_page() */
219 dp->context_bi.bi_sector = (sector_t)bvec.bv_len;
220}
221
222static void bio_next_page(struct dpages *dp)
223{
224 unsigned int len = (unsigned int)dp->context_bi.bi_sector;
225
226 bvec_iter_advance((struct bio_vec *)dp->context_ptr,
227 &dp->context_bi, len);
228}
229
230static void bio_dp_init(struct dpages *dp, struct bio *bio)
231{
232 dp->get_page = bio_get_page;
233 dp->next_page = bio_next_page;
234
235 /*
236 * We just use bvec iterator to retrieve pages, so it is ok to
237 * access the bvec table directly here
238 */
239 dp->context_ptr = bio->bi_io_vec;
240 dp->context_bi = bio->bi_iter;
241}
242
243/*
244 * Functions for getting the pages from a VMA.
245 */
246static void vm_get_page(struct dpages *dp,
247 struct page **p, unsigned long *len, unsigned *offset)
248{
249 *p = vmalloc_to_page(dp->context_ptr);
250 *offset = dp->context_u;
251 *len = PAGE_SIZE - dp->context_u;
252}
253
254static void vm_next_page(struct dpages *dp)
255{
256 dp->context_ptr += PAGE_SIZE - dp->context_u;
257 dp->context_u = 0;
258}
259
260static void vm_dp_init(struct dpages *dp, void *data)
261{
262 dp->get_page = vm_get_page;
263 dp->next_page = vm_next_page;
264 dp->context_u = offset_in_page(data);
265 dp->context_ptr = data;
266}
267
268/*
269 * Functions for getting the pages from kernel memory.
270 */
271static void km_get_page(struct dpages *dp, struct page **p, unsigned long *len,
272 unsigned *offset)
273{
274 *p = virt_to_page(dp->context_ptr);
275 *offset = dp->context_u;
276 *len = PAGE_SIZE - dp->context_u;
277}
278
279static void km_next_page(struct dpages *dp)
280{
281 dp->context_ptr += PAGE_SIZE - dp->context_u;
282 dp->context_u = 0;
283}
284
285static void km_dp_init(struct dpages *dp, void *data)
286{
287 dp->get_page = km_get_page;
288 dp->next_page = km_next_page;
289 dp->context_u = offset_in_page(data);
290 dp->context_ptr = data;
291}
292
293/*-----------------------------------------------------------------
294 * IO routines that accept a list of pages.
295 *---------------------------------------------------------------*/
296static void do_region(const blk_opf_t opf, unsigned region,
297 struct dm_io_region *where, struct dpages *dp,
298 struct io *io)
299{
300 struct bio *bio;
301 struct page *page;
302 unsigned long len;
303 unsigned offset;
304 unsigned num_bvecs;
305 sector_t remaining = where->count;
306 struct request_queue *q = bdev_get_queue(where->bdev);
307 sector_t num_sectors;
308 unsigned int special_cmd_max_sectors;
309 const enum req_op op = opf & REQ_OP_MASK;
310
311 /*
312 * Reject unsupported discard and write same requests.
313 */
314 if (op == REQ_OP_DISCARD)
315 special_cmd_max_sectors = bdev_max_discard_sectors(where->bdev);
316 else if (op == REQ_OP_WRITE_ZEROES)
317 special_cmd_max_sectors = q->limits.max_write_zeroes_sectors;
318 if ((op == REQ_OP_DISCARD || op == REQ_OP_WRITE_ZEROES) &&
319 special_cmd_max_sectors == 0) {
320 atomic_inc(&io->count);
321 dec_count(io, region, BLK_STS_NOTSUPP);
322 return;
323 }
324
325 /*
326 * where->count may be zero if op holds a flush and we need to
327 * send a zero-sized flush.
328 */
329 do {
330 /*
331 * Allocate a suitably sized-bio.
332 */
333 switch (op) {
334 case REQ_OP_DISCARD:
335 case REQ_OP_WRITE_ZEROES:
336 num_bvecs = 0;
337 break;
338 default:
339 num_bvecs = bio_max_segs(dm_sector_div_up(remaining,
340 (PAGE_SIZE >> SECTOR_SHIFT)));
341 }
342
343 bio = bio_alloc_bioset(where->bdev, num_bvecs, opf, GFP_NOIO,
344 &io->client->bios);
345 bio->bi_iter.bi_sector = where->sector + (where->count - remaining);
346 bio->bi_end_io = endio;
347 store_io_and_region_in_bio(bio, io, region);
348
349 if (op == REQ_OP_DISCARD || op == REQ_OP_WRITE_ZEROES) {
350 num_sectors = min_t(sector_t, special_cmd_max_sectors, remaining);
351 bio->bi_iter.bi_size = num_sectors << SECTOR_SHIFT;
352 remaining -= num_sectors;
353 } else while (remaining) {
354 /*
355 * Try and add as many pages as possible.
356 */
357 dp->get_page(dp, &page, &len, &offset);
358 len = min(len, to_bytes(remaining));
359 if (!bio_add_page(bio, page, len, offset))
360 break;
361
362 offset = 0;
363 remaining -= to_sector(len);
364 dp->next_page(dp);
365 }
366
367 atomic_inc(&io->count);
368 submit_bio(bio);
369 } while (remaining);
370}
371
372static void dispatch_io(blk_opf_t opf, unsigned int num_regions,
373 struct dm_io_region *where, struct dpages *dp,
374 struct io *io, int sync)
375{
376 int i;
377 struct dpages old_pages = *dp;
378
379 BUG_ON(num_regions > DM_IO_MAX_REGIONS);
380
381 if (sync)
382 opf |= REQ_SYNC;
383
384 /*
385 * For multiple regions we need to be careful to rewind
386 * the dp object for each call to do_region.
387 */
388 for (i = 0; i < num_regions; i++) {
389 *dp = old_pages;
390 if (where[i].count || (opf & REQ_PREFLUSH))
391 do_region(opf, i, where + i, dp, io);
392 }
393
394 /*
395 * Drop the extra reference that we were holding to avoid
396 * the io being completed too early.
397 */
398 dec_count(io, 0, 0);
399}
400
401struct sync_io {
402 unsigned long error_bits;
403 struct completion wait;
404};
405
406static void sync_io_complete(unsigned long error, void *context)
407{
408 struct sync_io *sio = context;
409
410 sio->error_bits = error;
411 complete(&sio->wait);
412}
413
414static int sync_io(struct dm_io_client *client, unsigned int num_regions,
415 struct dm_io_region *where, blk_opf_t opf, struct dpages *dp,
416 unsigned long *error_bits)
417{
418 struct io *io;
419 struct sync_io sio;
420
421 if (num_regions > 1 && !op_is_write(opf)) {
422 WARN_ON(1);
423 return -EIO;
424 }
425
426 init_completion(&sio.wait);
427
428 io = mempool_alloc(&client->pool, GFP_NOIO);
429 io->error_bits = 0;
430 atomic_set(&io->count, 1); /* see dispatch_io() */
431 io->client = client;
432 io->callback = sync_io_complete;
433 io->context = &sio;
434
435 io->vma_invalidate_address = dp->vma_invalidate_address;
436 io->vma_invalidate_size = dp->vma_invalidate_size;
437
438 dispatch_io(opf, num_regions, where, dp, io, 1);
439
440 wait_for_completion_io(&sio.wait);
441
442 if (error_bits)
443 *error_bits = sio.error_bits;
444
445 return sio.error_bits ? -EIO : 0;
446}
447
448static int async_io(struct dm_io_client *client, unsigned int num_regions,
449 struct dm_io_region *where, blk_opf_t opf,
450 struct dpages *dp, io_notify_fn fn, void *context)
451{
452 struct io *io;
453
454 if (num_regions > 1 && !op_is_write(opf)) {
455 WARN_ON(1);
456 fn(1, context);
457 return -EIO;
458 }
459
460 io = mempool_alloc(&client->pool, GFP_NOIO);
461 io->error_bits = 0;
462 atomic_set(&io->count, 1); /* see dispatch_io() */
463 io->client = client;
464 io->callback = fn;
465 io->context = context;
466
467 io->vma_invalidate_address = dp->vma_invalidate_address;
468 io->vma_invalidate_size = dp->vma_invalidate_size;
469
470 dispatch_io(opf, num_regions, where, dp, io, 0);
471 return 0;
472}
473
474static int dp_init(struct dm_io_request *io_req, struct dpages *dp,
475 unsigned long size)
476{
477 /* Set up dpages based on memory type */
478
479 dp->vma_invalidate_address = NULL;
480 dp->vma_invalidate_size = 0;
481
482 switch (io_req->mem.type) {
483 case DM_IO_PAGE_LIST:
484 list_dp_init(dp, io_req->mem.ptr.pl, io_req->mem.offset);
485 break;
486
487 case DM_IO_BIO:
488 bio_dp_init(dp, io_req->mem.ptr.bio);
489 break;
490
491 case DM_IO_VMA:
492 flush_kernel_vmap_range(io_req->mem.ptr.vma, size);
493 if ((io_req->bi_opf & REQ_OP_MASK) == REQ_OP_READ) {
494 dp->vma_invalidate_address = io_req->mem.ptr.vma;
495 dp->vma_invalidate_size = size;
496 }
497 vm_dp_init(dp, io_req->mem.ptr.vma);
498 break;
499
500 case DM_IO_KMEM:
501 km_dp_init(dp, io_req->mem.ptr.addr);
502 break;
503
504 default:
505 return -EINVAL;
506 }
507
508 return 0;
509}
510
511int dm_io(struct dm_io_request *io_req, unsigned num_regions,
512 struct dm_io_region *where, unsigned long *sync_error_bits)
513{
514 int r;
515 struct dpages dp;
516
517 r = dp_init(io_req, &dp, (unsigned long)where->count << SECTOR_SHIFT);
518 if (r)
519 return r;
520
521 if (!io_req->notify.fn)
522 return sync_io(io_req->client, num_regions, where,
523 io_req->bi_opf, &dp, sync_error_bits);
524
525 return async_io(io_req->client, num_regions, where,
526 io_req->bi_opf, &dp, io_req->notify.fn,
527 io_req->notify.context);
528}
529EXPORT_SYMBOL(dm_io);
530
531int __init dm_io_init(void)
532{
533 _dm_io_cache = KMEM_CACHE(io, 0);
534 if (!_dm_io_cache)
535 return -ENOMEM;
536
537 return 0;
538}
539
540void dm_io_exit(void)
541{
542 kmem_cache_destroy(_dm_io_cache);
543 _dm_io_cache = NULL;
544}