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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
23struct dm_io_client {
24 mempool_t *pool;
25 struct bio_set *bios;
26};
27
28
29
30
31
32struct io {
33 unsigned long error_bits;
34 atomic_t count;
35 struct task_struct *sleeper;
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
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 if (client->pool)
69 mempool_destroy(client->pool);
70 kfree(client);
71 return ERR_PTR(-ENOMEM);
72}
73EXPORT_SYMBOL(dm_io_client_create);
74
75void dm_io_client_destroy(struct dm_io_client *client)
76{
77 mempool_destroy(client->pool);
78 bioset_free(client->bios);
79 kfree(client);
80}
81EXPORT_SYMBOL(dm_io_client_destroy);
82
83
84
85
86
87
88
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
112
113
114static void dec_count(struct io *io, unsigned int region, int error)
115{
116 if (error)
117 set_bit(region, &io->error_bits);
118
119 if (atomic_dec_and_test(&io->count)) {
120 if (io->vma_invalidate_size)
121 invalidate_kernel_vmap_range(io->vma_invalidate_address,
122 io->vma_invalidate_size);
123
124 if (io->sleeper)
125 wake_up_process(io->sleeper);
126
127 else {
128 unsigned long r = io->error_bits;
129 io_notify_fn fn = io->callback;
130 void *context = io->context;
131
132 mempool_free(io, io->client->pool);
133 fn(r, context);
134 }
135 }
136}
137
138static void endio(struct bio *bio, int error)
139{
140 struct io *io;
141 unsigned region;
142
143 if (error && bio_data_dir(bio) == READ)
144 zero_fill_bio(bio);
145
146
147
148
149 retrieve_io_and_region_from_bio(bio, &io, ®ion);
150
151 bio_put(bio);
152
153 dec_count(io, region, error);
154}
155
156
157
158
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
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
203
204static void bvec_get_page(struct dpages *dp,
205 struct page **p, unsigned long *len, unsigned *offset)
206{
207 struct bio_vec *bvec = (struct bio_vec *) dp->context_ptr;
208 *p = bvec->bv_page;
209 *len = bvec->bv_len;
210 *offset = bvec->bv_offset;
211}
212
213static void bvec_next_page(struct dpages *dp)
214{
215 struct bio_vec *bvec = (struct bio_vec *) dp->context_ptr;
216 dp->context_ptr = bvec + 1;
217}
218
219static void bvec_dp_init(struct dpages *dp, struct bio_vec *bvec)
220{
221 dp->get_page = bvec_get_page;
222 dp->next_page = bvec_next_page;
223 dp->context_ptr = bvec;
224}
225
226
227
228
229static void vm_get_page(struct dpages *dp,
230 struct page **p, unsigned long *len, unsigned *offset)
231{
232 *p = vmalloc_to_page(dp->context_ptr);
233 *offset = dp->context_u;
234 *len = PAGE_SIZE - dp->context_u;
235}
236
237static void vm_next_page(struct dpages *dp)
238{
239 dp->context_ptr += PAGE_SIZE - dp->context_u;
240 dp->context_u = 0;
241}
242
243static void vm_dp_init(struct dpages *dp, void *data)
244{
245 dp->get_page = vm_get_page;
246 dp->next_page = vm_next_page;
247 dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
248 dp->context_ptr = data;
249}
250
251
252
253
254static void km_get_page(struct dpages *dp, struct page **p, unsigned long *len,
255 unsigned *offset)
256{
257 *p = virt_to_page(dp->context_ptr);
258 *offset = dp->context_u;
259 *len = PAGE_SIZE - dp->context_u;
260}
261
262static void km_next_page(struct dpages *dp)
263{
264 dp->context_ptr += PAGE_SIZE - dp->context_u;
265 dp->context_u = 0;
266}
267
268static void km_dp_init(struct dpages *dp, void *data)
269{
270 dp->get_page = km_get_page;
271 dp->next_page = km_next_page;
272 dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
273 dp->context_ptr = data;
274}
275
276
277
278
279static void do_region(int rw, unsigned region, struct dm_io_region *where,
280 struct dpages *dp, struct io *io)
281{
282 struct bio *bio;
283 struct page *page;
284 unsigned long len;
285 unsigned offset;
286 unsigned num_bvecs;
287 sector_t remaining = where->count;
288 struct request_queue *q = bdev_get_queue(where->bdev);
289 unsigned short logical_block_size = queue_logical_block_size(q);
290 sector_t num_sectors;
291
292
293
294
295
296 do {
297
298
299
300 if ((rw & REQ_DISCARD) || (rw & REQ_WRITE_SAME))
301 num_bvecs = 1;
302 else
303 num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev),
304 dm_sector_div_up(remaining, (PAGE_SIZE >> SECTOR_SHIFT)));
305
306 bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios);
307 bio->bi_sector = where->sector + (where->count - remaining);
308 bio->bi_bdev = where->bdev;
309 bio->bi_end_io = endio;
310 store_io_and_region_in_bio(bio, io, region);
311
312 if (rw & REQ_DISCARD) {
313 num_sectors = min_t(sector_t, q->limits.max_discard_sectors, remaining);
314 bio->bi_size = num_sectors << SECTOR_SHIFT;
315 remaining -= num_sectors;
316 } else if (rw & REQ_WRITE_SAME) {
317
318
319
320 dp->get_page(dp, &page, &len, &offset);
321 bio_add_page(bio, page, logical_block_size, offset);
322 num_sectors = min_t(sector_t, q->limits.max_write_same_sectors, remaining);
323 bio->bi_size = num_sectors << SECTOR_SHIFT;
324
325 offset = 0;
326 remaining -= num_sectors;
327 dp->next_page(dp);
328 } else while (remaining) {
329
330
331
332 dp->get_page(dp, &page, &len, &offset);
333 len = min(len, to_bytes(remaining));
334 if (!bio_add_page(bio, page, len, offset))
335 break;
336
337 offset = 0;
338 remaining -= to_sector(len);
339 dp->next_page(dp);
340 }
341
342 atomic_inc(&io->count);
343 submit_bio(rw, bio);
344 } while (remaining);
345}
346
347static void dispatch_io(int rw, unsigned int num_regions,
348 struct dm_io_region *where, struct dpages *dp,
349 struct io *io, int sync)
350{
351 int i;
352 struct dpages old_pages = *dp;
353
354 BUG_ON(num_regions > DM_IO_MAX_REGIONS);
355
356 if (sync)
357 rw |= REQ_SYNC;
358
359
360
361
362
363 for (i = 0; i < num_regions; i++) {
364 *dp = old_pages;
365 if (where[i].count || (rw & REQ_FLUSH))
366 do_region(rw, i, where + i, dp, io);
367 }
368
369
370
371
372
373 dec_count(io, 0, 0);
374}
375
376static int sync_io(struct dm_io_client *client, unsigned int num_regions,
377 struct dm_io_region *where, int rw, struct dpages *dp,
378 unsigned long *error_bits)
379{
380
381
382
383
384
385
386 volatile char io_[sizeof(struct io) + __alignof__(struct io) - 1];
387 struct io *io = (struct io *)PTR_ALIGN(&io_, __alignof__(struct io));
388
389 if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
390 WARN_ON(1);
391 return -EIO;
392 }
393
394 io->error_bits = 0;
395 atomic_set(&io->count, 1);
396 io->sleeper = current;
397 io->client = client;
398
399 io->vma_invalidate_address = dp->vma_invalidate_address;
400 io->vma_invalidate_size = dp->vma_invalidate_size;
401
402 dispatch_io(rw, num_regions, where, dp, io, 1);
403
404 while (1) {
405 set_current_state(TASK_UNINTERRUPTIBLE);
406
407 if (!atomic_read(&io->count))
408 break;
409
410 io_schedule();
411 }
412 set_current_state(TASK_RUNNING);
413
414 if (error_bits)
415 *error_bits = io->error_bits;
416
417 return io->error_bits ? -EIO : 0;
418}
419
420static int async_io(struct dm_io_client *client, unsigned int num_regions,
421 struct dm_io_region *where, int rw, struct dpages *dp,
422 io_notify_fn fn, void *context)
423{
424 struct io *io;
425
426 if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
427 WARN_ON(1);
428 fn(1, context);
429 return -EIO;
430 }
431
432 io = mempool_alloc(client->pool, GFP_NOIO);
433 io->error_bits = 0;
434 atomic_set(&io->count, 1);
435 io->sleeper = NULL;
436 io->client = client;
437 io->callback = fn;
438 io->context = context;
439
440 io->vma_invalidate_address = dp->vma_invalidate_address;
441 io->vma_invalidate_size = dp->vma_invalidate_size;
442
443 dispatch_io(rw, num_regions, where, dp, io, 0);
444 return 0;
445}
446
447static int dp_init(struct dm_io_request *io_req, struct dpages *dp,
448 unsigned long size)
449{
450
451
452 dp->vma_invalidate_address = NULL;
453 dp->vma_invalidate_size = 0;
454
455 switch (io_req->mem.type) {
456 case DM_IO_PAGE_LIST:
457 list_dp_init(dp, io_req->mem.ptr.pl, io_req->mem.offset);
458 break;
459
460 case DM_IO_BVEC:
461 bvec_dp_init(dp, io_req->mem.ptr.bvec);
462 break;
463
464 case DM_IO_VMA:
465 flush_kernel_vmap_range(io_req->mem.ptr.vma, size);
466 if ((io_req->bi_rw & RW_MASK) == READ) {
467 dp->vma_invalidate_address = io_req->mem.ptr.vma;
468 dp->vma_invalidate_size = size;
469 }
470 vm_dp_init(dp, io_req->mem.ptr.vma);
471 break;
472
473 case DM_IO_KMEM:
474 km_dp_init(dp, io_req->mem.ptr.addr);
475 break;
476
477 default:
478 return -EINVAL;
479 }
480
481 return 0;
482}
483
484
485
486
487
488
489
490
491
492int dm_io(struct dm_io_request *io_req, unsigned num_regions,
493 struct dm_io_region *where, unsigned long *sync_error_bits)
494{
495 int r;
496 struct dpages dp;
497
498 r = dp_init(io_req, &dp, (unsigned long)where->count << SECTOR_SHIFT);
499 if (r)
500 return r;
501
502 if (!io_req->notify.fn)
503 return sync_io(io_req->client, num_regions, where,
504 io_req->bi_rw, &dp, sync_error_bits);
505
506 return async_io(io_req->client, num_regions, where, io_req->bi_rw,
507 &dp, io_req->notify.fn, io_req->notify.context);
508}
509EXPORT_SYMBOL(dm_io);
510
511int __init dm_io_init(void)
512{
513 _dm_io_cache = KMEM_CACHE(io, 0);
514 if (!_dm_io_cache)
515 return -ENOMEM;
516
517 return 0;
518}
519
520void dm_io_exit(void)
521{
522 kmem_cache_destroy(_dm_io_cache);
523 _dm_io_cache = NULL;
524}
525