Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2003 Sistina Software | |
891ce207 | 3 | * Copyright (C) 2006 Red Hat GmbH |
1da177e4 LT |
4 | * |
5 | * This file is released under the GPL. | |
6 | */ | |
7 | ||
952b3557 MP |
8 | #include "dm.h" |
9 | ||
586e80e6 | 10 | #include <linux/device-mapper.h> |
1da177e4 LT |
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> | |
a765e20e | 17 | #include <linux/dm-io.h> |
1da177e4 | 18 | |
f1e53987 MP |
19 | #define DM_MSG_PREFIX "io" |
20 | ||
21 | #define DM_IO_MAX_REGIONS BITS_PER_LONG | |
bda8efec MP |
22 | #define MIN_IOS 16 |
23 | #define MIN_BIOS 16 | |
f1e53987 | 24 | |
891ce207 HM |
25 | struct dm_io_client { |
26 | mempool_t *pool; | |
27 | struct bio_set *bios; | |
28 | }; | |
29 | ||
f1e53987 MP |
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 | */ | |
1da177e4 | 34 | struct io { |
e01fd7ee | 35 | unsigned long error_bits; |
1da177e4 LT |
36 | atomic_t count; |
37 | struct task_struct *sleeper; | |
891ce207 | 38 | struct dm_io_client *client; |
1da177e4 LT |
39 | io_notify_fn callback; |
40 | void *context; | |
f1e53987 | 41 | } __attribute__((aligned(DM_IO_MAX_REGIONS))); |
1da177e4 | 42 | |
952b3557 MP |
43 | static struct kmem_cache *_dm_io_cache; |
44 | ||
c8b03afe HM |
45 | /* |
46 | * Create a client with mempool and bioset. | |
47 | */ | |
bda8efec | 48 | struct dm_io_client *dm_io_client_create(void) |
c8b03afe | 49 | { |
c8b03afe HM |
50 | struct dm_io_client *client; |
51 | ||
52 | client = kmalloc(sizeof(*client), GFP_KERNEL); | |
53 | if (!client) | |
54 | return ERR_PTR(-ENOMEM); | |
55 | ||
bda8efec | 56 | client->pool = mempool_create_slab_pool(MIN_IOS, _dm_io_cache); |
c8b03afe HM |
57 | if (!client->pool) |
58 | goto bad; | |
59 | ||
bda8efec | 60 | client->bios = bioset_create(MIN_BIOS, 0); |
c8b03afe HM |
61 | if (!client->bios) |
62 | goto bad; | |
63 | ||
64 | return client; | |
65 | ||
66 | bad: | |
67 | if (client->pool) | |
68 | mempool_destroy(client->pool); | |
69 | kfree(client); | |
70 | return ERR_PTR(-ENOMEM); | |
71 | } | |
72 | EXPORT_SYMBOL(dm_io_client_create); | |
73 | ||
c8b03afe HM |
74 | void dm_io_client_destroy(struct dm_io_client *client) |
75 | { | |
76 | mempool_destroy(client->pool); | |
77 | bioset_free(client->bios); | |
78 | kfree(client); | |
79 | } | |
80 | EXPORT_SYMBOL(dm_io_client_destroy); | |
81 | ||
1da177e4 LT |
82 | /*----------------------------------------------------------------- |
83 | * We need to keep track of which region a bio is doing io for. | |
f1e53987 MP |
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. | |
1da177e4 | 88 | *---------------------------------------------------------------*/ |
f1e53987 MP |
89 | static void store_io_and_region_in_bio(struct bio *bio, struct io *io, |
90 | unsigned region) | |
1da177e4 | 91 | { |
f1e53987 MP |
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); | |
1da177e4 LT |
98 | } |
99 | ||
f1e53987 MP |
100 | static void retrieve_io_and_region_from_bio(struct bio *bio, struct io **io, |
101 | unsigned *region) | |
1da177e4 | 102 | { |
f1e53987 MP |
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); | |
1da177e4 LT |
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 | *---------------------------------------------------------------*/ | |
113 | static void dec_count(struct io *io, unsigned int region, int error) | |
114 | { | |
d87f4c14 | 115 | if (error) |
e01fd7ee | 116 | set_bit(region, &io->error_bits); |
1da177e4 LT |
117 | |
118 | if (atomic_dec_and_test(&io->count)) { | |
119 | if (io->sleeper) | |
120 | wake_up_process(io->sleeper); | |
121 | ||
122 | else { | |
e01fd7ee | 123 | unsigned long r = io->error_bits; |
1da177e4 LT |
124 | io_notify_fn fn = io->callback; |
125 | void *context = io->context; | |
126 | ||
bf17ce3a | 127 | mempool_free(io, io->client->pool); |
1da177e4 LT |
128 | fn(r, context); |
129 | } | |
130 | } | |
131 | } | |
132 | ||
6712ecf8 | 133 | static void endio(struct bio *bio, int error) |
1da177e4 | 134 | { |
c897feb3 HM |
135 | struct io *io; |
136 | unsigned region; | |
1da177e4 | 137 | |
1da177e4 LT |
138 | if (error && bio_data_dir(bio) == READ) |
139 | zero_fill_bio(bio); | |
140 | ||
c897feb3 HM |
141 | /* |
142 | * The bio destructor in bio_put() may use the io object. | |
143 | */ | |
f1e53987 | 144 | retrieve_io_and_region_from_bio(bio, &io, ®ion); |
c897feb3 | 145 | |
1da177e4 LT |
146 | bio_put(bio); |
147 | ||
c897feb3 | 148 | dec_count(io, region, error); |
1da177e4 LT |
149 | } |
150 | ||
151 | /*----------------------------------------------------------------- | |
152 | * These little objects provide an abstraction for getting a new | |
153 | * destination page for io. | |
154 | *---------------------------------------------------------------*/ | |
155 | struct dpages { | |
156 | void (*get_page)(struct dpages *dp, | |
157 | struct page **p, unsigned long *len, unsigned *offset); | |
158 | void (*next_page)(struct dpages *dp); | |
159 | ||
160 | unsigned context_u; | |
161 | void *context_ptr; | |
162 | }; | |
163 | ||
164 | /* | |
165 | * Functions for getting the pages from a list. | |
166 | */ | |
167 | static void list_get_page(struct dpages *dp, | |
168 | struct page **p, unsigned long *len, unsigned *offset) | |
169 | { | |
170 | unsigned o = dp->context_u; | |
171 | struct page_list *pl = (struct page_list *) dp->context_ptr; | |
172 | ||
173 | *p = pl->page; | |
174 | *len = PAGE_SIZE - o; | |
175 | *offset = o; | |
176 | } | |
177 | ||
178 | static void list_next_page(struct dpages *dp) | |
179 | { | |
180 | struct page_list *pl = (struct page_list *) dp->context_ptr; | |
181 | dp->context_ptr = pl->next; | |
182 | dp->context_u = 0; | |
183 | } | |
184 | ||
185 | static void list_dp_init(struct dpages *dp, struct page_list *pl, unsigned offset) | |
186 | { | |
187 | dp->get_page = list_get_page; | |
188 | dp->next_page = list_next_page; | |
189 | dp->context_u = offset; | |
190 | dp->context_ptr = pl; | |
191 | } | |
192 | ||
193 | /* | |
194 | * Functions for getting the pages from a bvec. | |
195 | */ | |
196 | static void bvec_get_page(struct dpages *dp, | |
197 | struct page **p, unsigned long *len, unsigned *offset) | |
198 | { | |
199 | struct bio_vec *bvec = (struct bio_vec *) dp->context_ptr; | |
200 | *p = bvec->bv_page; | |
201 | *len = bvec->bv_len; | |
202 | *offset = bvec->bv_offset; | |
203 | } | |
204 | ||
205 | static void bvec_next_page(struct dpages *dp) | |
206 | { | |
207 | struct bio_vec *bvec = (struct bio_vec *) dp->context_ptr; | |
208 | dp->context_ptr = bvec + 1; | |
209 | } | |
210 | ||
211 | static void bvec_dp_init(struct dpages *dp, struct bio_vec *bvec) | |
212 | { | |
213 | dp->get_page = bvec_get_page; | |
214 | dp->next_page = bvec_next_page; | |
215 | dp->context_ptr = bvec; | |
216 | } | |
217 | ||
c8b03afe HM |
218 | /* |
219 | * Functions for getting the pages from a VMA. | |
220 | */ | |
1da177e4 LT |
221 | static void vm_get_page(struct dpages *dp, |
222 | struct page **p, unsigned long *len, unsigned *offset) | |
223 | { | |
224 | *p = vmalloc_to_page(dp->context_ptr); | |
225 | *offset = dp->context_u; | |
226 | *len = PAGE_SIZE - dp->context_u; | |
227 | } | |
228 | ||
229 | static void vm_next_page(struct dpages *dp) | |
230 | { | |
231 | dp->context_ptr += PAGE_SIZE - dp->context_u; | |
232 | dp->context_u = 0; | |
233 | } | |
234 | ||
235 | static void vm_dp_init(struct dpages *dp, void *data) | |
236 | { | |
237 | dp->get_page = vm_get_page; | |
238 | dp->next_page = vm_next_page; | |
239 | dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1); | |
240 | dp->context_ptr = data; | |
241 | } | |
242 | ||
3676347a PO |
243 | static void dm_bio_destructor(struct bio *bio) |
244 | { | |
f1e53987 MP |
245 | unsigned region; |
246 | struct io *io; | |
247 | ||
248 | retrieve_io_and_region_from_bio(bio, &io, ®ion); | |
891ce207 | 249 | |
bf17ce3a | 250 | bio_free(bio, io->client->bios); |
3676347a PO |
251 | } |
252 | ||
c8b03afe HM |
253 | /* |
254 | * Functions for getting the pages from kernel memory. | |
255 | */ | |
256 | static 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 | ||
264 | static void km_next_page(struct dpages *dp) | |
265 | { | |
266 | dp->context_ptr += PAGE_SIZE - dp->context_u; | |
267 | dp->context_u = 0; | |
268 | } | |
269 | ||
270 | static 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 = ((unsigned long) data) & (PAGE_SIZE - 1); | |
275 | dp->context_ptr = data; | |
276 | } | |
277 | ||
1da177e4 LT |
278 | /*----------------------------------------------------------------- |
279 | * IO routines that accept a list of pages. | |
280 | *---------------------------------------------------------------*/ | |
22a1ceb1 | 281 | static void do_region(int rw, unsigned region, struct dm_io_region *where, |
1da177e4 LT |
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 | ||
12fc0f49 | 291 | /* |
d87f4c14 TH |
292 | * where->count may be zero if rw holds a flush and we need to |
293 | * send a zero-sized flush. | |
12fc0f49 MP |
294 | */ |
295 | do { | |
1da177e4 | 296 | /* |
f1e53987 | 297 | * Allocate a suitably sized-bio. |
1da177e4 | 298 | */ |
596f138e JN |
299 | num_bvecs = dm_sector_div_up(remaining, |
300 | (PAGE_SIZE >> SECTOR_SHIFT)); | |
f1e53987 | 301 | num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev), num_bvecs); |
bf17ce3a | 302 | bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios); |
1da177e4 LT |
303 | bio->bi_sector = where->sector + (where->count - remaining); |
304 | bio->bi_bdev = where->bdev; | |
305 | bio->bi_end_io = endio; | |
3676347a | 306 | bio->bi_destructor = dm_bio_destructor; |
f1e53987 | 307 | store_io_and_region_in_bio(bio, io, region); |
1da177e4 LT |
308 | |
309 | /* | |
310 | * Try and add as many pages as possible. | |
311 | */ | |
312 | while (remaining) { | |
313 | dp->get_page(dp, &page, &len, &offset); | |
314 | len = min(len, to_bytes(remaining)); | |
315 | if (!bio_add_page(bio, page, len, offset)) | |
316 | break; | |
317 | ||
318 | offset = 0; | |
319 | remaining -= to_sector(len); | |
320 | dp->next_page(dp); | |
321 | } | |
322 | ||
323 | atomic_inc(&io->count); | |
324 | submit_bio(rw, bio); | |
12fc0f49 | 325 | } while (remaining); |
1da177e4 LT |
326 | } |
327 | ||
328 | static void dispatch_io(int rw, unsigned int num_regions, | |
22a1ceb1 | 329 | struct dm_io_region *where, struct dpages *dp, |
1da177e4 LT |
330 | struct io *io, int sync) |
331 | { | |
332 | int i; | |
333 | struct dpages old_pages = *dp; | |
334 | ||
f1e53987 MP |
335 | BUG_ON(num_regions > DM_IO_MAX_REGIONS); |
336 | ||
1da177e4 | 337 | if (sync) |
721a9602 | 338 | rw |= REQ_SYNC; |
1da177e4 LT |
339 | |
340 | /* | |
341 | * For multiple regions we need to be careful to rewind | |
342 | * the dp object for each call to do_region. | |
343 | */ | |
344 | for (i = 0; i < num_regions; i++) { | |
345 | *dp = old_pages; | |
d87f4c14 | 346 | if (where[i].count || (rw & REQ_FLUSH)) |
1da177e4 LT |
347 | do_region(rw, i, where + i, dp, io); |
348 | } | |
349 | ||
350 | /* | |
f00b16ad | 351 | * Drop the extra reference that we were holding to avoid |
1da177e4 LT |
352 | * the io being completed too early. |
353 | */ | |
354 | dec_count(io, 0, 0); | |
355 | } | |
356 | ||
891ce207 | 357 | static int sync_io(struct dm_io_client *client, unsigned int num_regions, |
22a1ceb1 | 358 | struct dm_io_region *where, int rw, struct dpages *dp, |
891ce207 | 359 | unsigned long *error_bits) |
1da177e4 | 360 | { |
f1e53987 MP |
361 | /* |
362 | * gcc <= 4.3 can't do the alignment for stack variables, so we must | |
363 | * align it on our own. | |
364 | * volatile prevents the optimizer from removing or reusing | |
365 | * "io_" field from the stack frame (allowed in ANSI C). | |
366 | */ | |
367 | volatile char io_[sizeof(struct io) + __alignof__(struct io) - 1]; | |
368 | struct io *io = (struct io *)PTR_ALIGN(&io_, __alignof__(struct io)); | |
1da177e4 | 369 | |
7ff14a36 | 370 | if (num_regions > 1 && (rw & RW_MASK) != WRITE) { |
1da177e4 LT |
371 | WARN_ON(1); |
372 | return -EIO; | |
373 | } | |
374 | ||
f1e53987 | 375 | io->error_bits = 0; |
f1e53987 MP |
376 | atomic_set(&io->count, 1); /* see dispatch_io() */ |
377 | io->sleeper = current; | |
378 | io->client = client; | |
1da177e4 | 379 | |
f1e53987 | 380 | dispatch_io(rw, num_regions, where, dp, io, 1); |
1da177e4 LT |
381 | |
382 | while (1) { | |
383 | set_current_state(TASK_UNINTERRUPTIBLE); | |
384 | ||
f1e53987 | 385 | if (!atomic_read(&io->count)) |
1da177e4 LT |
386 | break; |
387 | ||
388 | io_schedule(); | |
389 | } | |
390 | set_current_state(TASK_RUNNING); | |
391 | ||
891ce207 | 392 | if (error_bits) |
f1e53987 | 393 | *error_bits = io->error_bits; |
891ce207 | 394 | |
f1e53987 | 395 | return io->error_bits ? -EIO : 0; |
1da177e4 LT |
396 | } |
397 | ||
891ce207 | 398 | static int async_io(struct dm_io_client *client, unsigned int num_regions, |
22a1ceb1 | 399 | struct dm_io_region *where, int rw, struct dpages *dp, |
891ce207 | 400 | io_notify_fn fn, void *context) |
1da177e4 LT |
401 | { |
402 | struct io *io; | |
403 | ||
7ff14a36 | 404 | if (num_regions > 1 && (rw & RW_MASK) != WRITE) { |
1da177e4 LT |
405 | WARN_ON(1); |
406 | fn(1, context); | |
407 | return -EIO; | |
408 | } | |
409 | ||
bf17ce3a | 410 | io = mempool_alloc(client->pool, GFP_NOIO); |
e01fd7ee | 411 | io->error_bits = 0; |
1da177e4 LT |
412 | atomic_set(&io->count, 1); /* see dispatch_io() */ |
413 | io->sleeper = NULL; | |
891ce207 | 414 | io->client = client; |
1da177e4 LT |
415 | io->callback = fn; |
416 | io->context = context; | |
417 | ||
418 | dispatch_io(rw, num_regions, where, dp, io, 0); | |
419 | return 0; | |
420 | } | |
421 | ||
c8b03afe HM |
422 | static int dp_init(struct dm_io_request *io_req, struct dpages *dp) |
423 | { | |
424 | /* Set up dpages based on memory type */ | |
425 | switch (io_req->mem.type) { | |
426 | case DM_IO_PAGE_LIST: | |
427 | list_dp_init(dp, io_req->mem.ptr.pl, io_req->mem.offset); | |
428 | break; | |
429 | ||
430 | case DM_IO_BVEC: | |
431 | bvec_dp_init(dp, io_req->mem.ptr.bvec); | |
432 | break; | |
433 | ||
434 | case DM_IO_VMA: | |
435 | vm_dp_init(dp, io_req->mem.ptr.vma); | |
436 | break; | |
437 | ||
438 | case DM_IO_KMEM: | |
439 | km_dp_init(dp, io_req->mem.ptr.addr); | |
440 | break; | |
441 | ||
442 | default: | |
443 | return -EINVAL; | |
444 | } | |
445 | ||
446 | return 0; | |
447 | } | |
448 | ||
449 | /* | |
7ff14a36 MP |
450 | * New collapsed (a)synchronous interface. |
451 | * | |
452 | * If the IO is asynchronous (i.e. it has notify.fn), you must either unplug | |
7b6d91da CH |
453 | * the queue with blk_unplug() some time later or set REQ_SYNC in |
454 | io_req->bi_rw. If you fail to do one of these, the IO will be submitted to | |
7ff14a36 | 455 | * the disk after q->unplug_delay, which defaults to 3ms in blk-settings.c. |
c8b03afe HM |
456 | */ |
457 | int dm_io(struct dm_io_request *io_req, unsigned num_regions, | |
22a1ceb1 | 458 | struct dm_io_region *where, unsigned long *sync_error_bits) |
c8b03afe HM |
459 | { |
460 | int r; | |
461 | struct dpages dp; | |
462 | ||
463 | r = dp_init(io_req, &dp); | |
464 | if (r) | |
465 | return r; | |
466 | ||
467 | if (!io_req->notify.fn) | |
468 | return sync_io(io_req->client, num_regions, where, | |
469 | io_req->bi_rw, &dp, sync_error_bits); | |
470 | ||
471 | return async_io(io_req->client, num_regions, where, io_req->bi_rw, | |
472 | &dp, io_req->notify.fn, io_req->notify.context); | |
473 | } | |
474 | EXPORT_SYMBOL(dm_io); | |
952b3557 MP |
475 | |
476 | int __init dm_io_init(void) | |
477 | { | |
478 | _dm_io_cache = KMEM_CACHE(io, 0); | |
479 | if (!_dm_io_cache) | |
480 | return -ENOMEM; | |
481 | ||
482 | return 0; | |
483 | } | |
484 | ||
485 | void dm_io_exit(void) | |
486 | { | |
487 | kmem_cache_destroy(_dm_io_cache); | |
488 | _dm_io_cache = NULL; | |
489 | } |