blob: 2fd6d4450637943963d88c948080cf4f0ed73a92 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (C) 2003 Sistina Software
Heinz Mauelshagen891ce202007-05-09 02:33:00 -07003 * Copyright (C) 2006 Red Hat GmbH
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 *
5 * This file is released under the GPL.
6 */
7
Mikulas Patocka586e80e2008-10-21 17:44:59 +01008#include <linux/device-mapper.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07009
10#include <linux/bio.h>
11#include <linux/mempool.h>
12#include <linux/module.h>
13#include <linux/sched.h>
14#include <linux/slab.h>
Alasdair G Kergona765e202008-04-24 22:02:01 +010015#include <linux/dm-io.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016
Heinz Mauelshagen891ce202007-05-09 02:33:00 -070017struct dm_io_client {
18 mempool_t *pool;
19 struct bio_set *bios;
20};
21
Linus Torvalds1da177e2005-04-16 15:20:36 -070022/* FIXME: can we shrink this ? */
23struct io {
Alasdair G Kergone01fd7e2008-04-24 21:43:14 +010024 unsigned long error_bits;
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 atomic_t count;
26 struct task_struct *sleeper;
Heinz Mauelshagen891ce202007-05-09 02:33:00 -070027 struct dm_io_client *client;
Linus Torvalds1da177e2005-04-16 15:20:36 -070028 io_notify_fn callback;
29 void *context;
30};
31
32/*
33 * io contexts are only dynamically allocated for asynchronous
34 * io. Since async io is likely to be the majority of io we'll
Heinz Mauelshagen891ce202007-05-09 02:33:00 -070035 * have the same number of io contexts as bios! (FIXME: must reduce this).
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 */
Heinz Mauelshagen891ce202007-05-09 02:33:00 -070037
Linus Torvalds1da177e2005-04-16 15:20:36 -070038static unsigned int pages_to_ios(unsigned int pages)
39{
40 return 4 * pages; /* too many ? */
41}
42
Heinz Mauelshagenc8b03af2007-05-09 02:33:01 -070043/*
44 * Create a client with mempool and bioset.
45 */
46struct dm_io_client *dm_io_client_create(unsigned num_pages)
47{
48 unsigned ios = pages_to_ios(num_pages);
49 struct dm_io_client *client;
50
51 client = kmalloc(sizeof(*client), GFP_KERNEL);
52 if (!client)
53 return ERR_PTR(-ENOMEM);
54
55 client->pool = mempool_create_kmalloc_pool(ios, sizeof(struct io));
56 if (!client->pool)
57 goto bad;
58
59 client->bios = bioset_create(16, 16);
60 if (!client->bios)
61 goto bad;
62
63 return client;
64
65 bad:
66 if (client->pool)
67 mempool_destroy(client->pool);
68 kfree(client);
69 return ERR_PTR(-ENOMEM);
70}
71EXPORT_SYMBOL(dm_io_client_create);
72
73int dm_io_client_resize(unsigned num_pages, struct dm_io_client *client)
74{
75 return mempool_resize(client->pool, pages_to_ios(num_pages),
76 GFP_KERNEL);
77}
78EXPORT_SYMBOL(dm_io_client_resize);
79
80void dm_io_client_destroy(struct dm_io_client *client)
81{
82 mempool_destroy(client->pool);
83 bioset_free(client->bios);
84 kfree(client);
85}
86EXPORT_SYMBOL(dm_io_client_destroy);
87
Linus Torvalds1da177e2005-04-16 15:20:36 -070088/*-----------------------------------------------------------------
89 * We need to keep track of which region a bio is doing io for.
90 * In order to save a memory allocation we store this the last
91 * bvec which we know is unused (blech).
92 * XXX This is ugly and can OOPS with some configs... find another way.
93 *---------------------------------------------------------------*/
94static inline void bio_set_region(struct bio *bio, unsigned region)
95{
Heinz Mauelshagenf00b16a2006-12-08 02:41:01 -080096 bio->bi_io_vec[bio->bi_max_vecs].bv_len = region;
Linus Torvalds1da177e2005-04-16 15:20:36 -070097}
98
99static inline unsigned bio_get_region(struct bio *bio)
100{
Heinz Mauelshagenf00b16a2006-12-08 02:41:01 -0800101 return bio->bi_io_vec[bio->bi_max_vecs].bv_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102}
103
104/*-----------------------------------------------------------------
105 * We need an io object to keep track of the number of bios that
106 * have been dispatched for a particular io.
107 *---------------------------------------------------------------*/
108static void dec_count(struct io *io, unsigned int region, int error)
109{
110 if (error)
Alasdair G Kergone01fd7e2008-04-24 21:43:14 +0100111 set_bit(region, &io->error_bits);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112
113 if (atomic_dec_and_test(&io->count)) {
114 if (io->sleeper)
115 wake_up_process(io->sleeper);
116
117 else {
Alasdair G Kergone01fd7e2008-04-24 21:43:14 +0100118 unsigned long r = io->error_bits;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 io_notify_fn fn = io->callback;
120 void *context = io->context;
121
Milan Brozbf17ce32007-05-09 02:33:05 -0700122 mempool_free(io, io->client->pool);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 fn(r, context);
124 }
125 }
126}
127
NeilBrown6712ecf2007-09-27 12:47:43 +0200128static void endio(struct bio *bio, int error)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129{
Heinz Mauelshagenc897feb2007-05-09 02:33:00 -0700130 struct io *io;
131 unsigned region;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 if (error && bio_data_dir(bio) == READ)
134 zero_fill_bio(bio);
135
Heinz Mauelshagenc897feb2007-05-09 02:33:00 -0700136 /*
137 * The bio destructor in bio_put() may use the io object.
138 */
139 io = bio->bi_private;
140 region = bio_get_region(bio);
141
Heinz Mauelshagenf00b16a2006-12-08 02:41:01 -0800142 bio->bi_max_vecs++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 bio_put(bio);
144
Heinz Mauelshagenc897feb2007-05-09 02:33:00 -0700145 dec_count(io, region, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146}
147
148/*-----------------------------------------------------------------
149 * These little objects provide an abstraction for getting a new
150 * destination page for io.
151 *---------------------------------------------------------------*/
152struct dpages {
153 void (*get_page)(struct dpages *dp,
154 struct page **p, unsigned long *len, unsigned *offset);
155 void (*next_page)(struct dpages *dp);
156
157 unsigned context_u;
158 void *context_ptr;
159};
160
161/*
162 * Functions for getting the pages from a list.
163 */
164static void list_get_page(struct dpages *dp,
165 struct page **p, unsigned long *len, unsigned *offset)
166{
167 unsigned o = dp->context_u;
168 struct page_list *pl = (struct page_list *) dp->context_ptr;
169
170 *p = pl->page;
171 *len = PAGE_SIZE - o;
172 *offset = o;
173}
174
175static void list_next_page(struct dpages *dp)
176{
177 struct page_list *pl = (struct page_list *) dp->context_ptr;
178 dp->context_ptr = pl->next;
179 dp->context_u = 0;
180}
181
182static void list_dp_init(struct dpages *dp, struct page_list *pl, unsigned offset)
183{
184 dp->get_page = list_get_page;
185 dp->next_page = list_next_page;
186 dp->context_u = offset;
187 dp->context_ptr = pl;
188}
189
190/*
191 * Functions for getting the pages from a bvec.
192 */
193static void bvec_get_page(struct dpages *dp,
194 struct page **p, unsigned long *len, unsigned *offset)
195{
196 struct bio_vec *bvec = (struct bio_vec *) dp->context_ptr;
197 *p = bvec->bv_page;
198 *len = bvec->bv_len;
199 *offset = bvec->bv_offset;
200}
201
202static void bvec_next_page(struct dpages *dp)
203{
204 struct bio_vec *bvec = (struct bio_vec *) dp->context_ptr;
205 dp->context_ptr = bvec + 1;
206}
207
208static void bvec_dp_init(struct dpages *dp, struct bio_vec *bvec)
209{
210 dp->get_page = bvec_get_page;
211 dp->next_page = bvec_next_page;
212 dp->context_ptr = bvec;
213}
214
Heinz Mauelshagenc8b03af2007-05-09 02:33:01 -0700215/*
216 * Functions for getting the pages from a VMA.
217 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218static void vm_get_page(struct dpages *dp,
219 struct page **p, unsigned long *len, unsigned *offset)
220{
221 *p = vmalloc_to_page(dp->context_ptr);
222 *offset = dp->context_u;
223 *len = PAGE_SIZE - dp->context_u;
224}
225
226static void vm_next_page(struct dpages *dp)
227{
228 dp->context_ptr += PAGE_SIZE - dp->context_u;
229 dp->context_u = 0;
230}
231
232static void vm_dp_init(struct dpages *dp, void *data)
233{
234 dp->get_page = vm_get_page;
235 dp->next_page = vm_next_page;
236 dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
237 dp->context_ptr = data;
238}
239
Peter Osterlund36763472005-09-06 15:16:42 -0700240static void dm_bio_destructor(struct bio *bio)
241{
Heinz Mauelshagen891ce202007-05-09 02:33:00 -0700242 struct io *io = bio->bi_private;
243
Milan Brozbf17ce32007-05-09 02:33:05 -0700244 bio_free(bio, io->client->bios);
Peter Osterlund36763472005-09-06 15:16:42 -0700245}
246
Heinz Mauelshagenc8b03af2007-05-09 02:33:01 -0700247/*
248 * Functions for getting the pages from kernel memory.
249 */
250static void km_get_page(struct dpages *dp, struct page **p, unsigned long *len,
251 unsigned *offset)
252{
253 *p = virt_to_page(dp->context_ptr);
254 *offset = dp->context_u;
255 *len = PAGE_SIZE - dp->context_u;
256}
257
258static void km_next_page(struct dpages *dp)
259{
260 dp->context_ptr += PAGE_SIZE - dp->context_u;
261 dp->context_u = 0;
262}
263
264static void km_dp_init(struct dpages *dp, void *data)
265{
266 dp->get_page = km_get_page;
267 dp->next_page = km_next_page;
268 dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
269 dp->context_ptr = data;
270}
271
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272/*-----------------------------------------------------------------
273 * IO routines that accept a list of pages.
274 *---------------------------------------------------------------*/
Heinz Mauelshagen22a1ceb2008-04-24 21:43:17 +0100275static void do_region(int rw, unsigned region, struct dm_io_region *where,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 struct dpages *dp, struct io *io)
277{
278 struct bio *bio;
279 struct page *page;
280 unsigned long len;
281 unsigned offset;
282 unsigned num_bvecs;
283 sector_t remaining = where->count;
284
285 while (remaining) {
286 /*
Heinz Mauelshagenf00b16a2006-12-08 02:41:01 -0800287 * Allocate a suitably sized-bio: we add an extra
288 * bvec for bio_get/set_region() and decrement bi_max_vecs
289 * to hide it from bio_add_page().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 */
Jun'ichi Nomura596f1382007-07-12 17:27:45 +0100291 num_bvecs = dm_sector_div_up(remaining,
292 (PAGE_SIZE >> SECTOR_SHIFT));
293 num_bvecs = 1 + min_t(int, bio_get_nr_vecs(where->bdev),
294 num_bvecs);
Milan Brozbf17ce32007-05-09 02:33:05 -0700295 bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 bio->bi_sector = where->sector + (where->count - remaining);
297 bio->bi_bdev = where->bdev;
298 bio->bi_end_io = endio;
299 bio->bi_private = io;
Peter Osterlund36763472005-09-06 15:16:42 -0700300 bio->bi_destructor = dm_bio_destructor;
Heinz Mauelshagenf00b16a2006-12-08 02:41:01 -0800301 bio->bi_max_vecs--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 bio_set_region(bio, region);
303
304 /*
305 * Try and add as many pages as possible.
306 */
307 while (remaining) {
308 dp->get_page(dp, &page, &len, &offset);
309 len = min(len, to_bytes(remaining));
310 if (!bio_add_page(bio, page, len, offset))
311 break;
312
313 offset = 0;
314 remaining -= to_sector(len);
315 dp->next_page(dp);
316 }
317
318 atomic_inc(&io->count);
319 submit_bio(rw, bio);
320 }
321}
322
323static void dispatch_io(int rw, unsigned int num_regions,
Heinz Mauelshagen22a1ceb2008-04-24 21:43:17 +0100324 struct dm_io_region *where, struct dpages *dp,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 struct io *io, int sync)
326{
327 int i;
328 struct dpages old_pages = *dp;
329
330 if (sync)
331 rw |= (1 << BIO_RW_SYNC);
332
333 /*
334 * For multiple regions we need to be careful to rewind
335 * the dp object for each call to do_region.
336 */
337 for (i = 0; i < num_regions; i++) {
338 *dp = old_pages;
339 if (where[i].count)
340 do_region(rw, i, where + i, dp, io);
341 }
342
343 /*
Heinz Mauelshagenf00b16a2006-12-08 02:41:01 -0800344 * Drop the extra reference that we were holding to avoid
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 * the io being completed too early.
346 */
347 dec_count(io, 0, 0);
348}
349
Heinz Mauelshagen891ce202007-05-09 02:33:00 -0700350static int sync_io(struct dm_io_client *client, unsigned int num_regions,
Heinz Mauelshagen22a1ceb2008-04-24 21:43:17 +0100351 struct dm_io_region *where, int rw, struct dpages *dp,
Heinz Mauelshagen891ce202007-05-09 02:33:00 -0700352 unsigned long *error_bits)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353{
354 struct io io;
355
Mikulas Patocka7ff14a32008-04-24 22:10:47 +0100356 if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 WARN_ON(1);
358 return -EIO;
359 }
360
Alasdair G Kergone01fd7e2008-04-24 21:43:14 +0100361 io.error_bits = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 atomic_set(&io.count, 1); /* see dispatch_io() */
363 io.sleeper = current;
Heinz Mauelshagen891ce202007-05-09 02:33:00 -0700364 io.client = client;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365
366 dispatch_io(rw, num_regions, where, dp, &io, 1);
367
368 while (1) {
369 set_current_state(TASK_UNINTERRUPTIBLE);
370
371 if (!atomic_read(&io.count) || signal_pending(current))
372 break;
373
374 io_schedule();
375 }
376 set_current_state(TASK_RUNNING);
377
378 if (atomic_read(&io.count))
379 return -EINTR;
380
Heinz Mauelshagen891ce202007-05-09 02:33:00 -0700381 if (error_bits)
Alasdair G Kergone01fd7e2008-04-24 21:43:14 +0100382 *error_bits = io.error_bits;
Heinz Mauelshagen891ce202007-05-09 02:33:00 -0700383
Alasdair G Kergone01fd7e2008-04-24 21:43:14 +0100384 return io.error_bits ? -EIO : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385}
386
Heinz Mauelshagen891ce202007-05-09 02:33:00 -0700387static int async_io(struct dm_io_client *client, unsigned int num_regions,
Heinz Mauelshagen22a1ceb2008-04-24 21:43:17 +0100388 struct dm_io_region *where, int rw, struct dpages *dp,
Heinz Mauelshagen891ce202007-05-09 02:33:00 -0700389 io_notify_fn fn, void *context)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390{
391 struct io *io;
392
Mikulas Patocka7ff14a32008-04-24 22:10:47 +0100393 if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 WARN_ON(1);
395 fn(1, context);
396 return -EIO;
397 }
398
Milan Brozbf17ce32007-05-09 02:33:05 -0700399 io = mempool_alloc(client->pool, GFP_NOIO);
Alasdair G Kergone01fd7e2008-04-24 21:43:14 +0100400 io->error_bits = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 atomic_set(&io->count, 1); /* see dispatch_io() */
402 io->sleeper = NULL;
Heinz Mauelshagen891ce202007-05-09 02:33:00 -0700403 io->client = client;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 io->callback = fn;
405 io->context = context;
406
407 dispatch_io(rw, num_regions, where, dp, io, 0);
408 return 0;
409}
410
Heinz Mauelshagenc8b03af2007-05-09 02:33:01 -0700411static int dp_init(struct dm_io_request *io_req, struct dpages *dp)
412{
413 /* Set up dpages based on memory type */
414 switch (io_req->mem.type) {
415 case DM_IO_PAGE_LIST:
416 list_dp_init(dp, io_req->mem.ptr.pl, io_req->mem.offset);
417 break;
418
419 case DM_IO_BVEC:
420 bvec_dp_init(dp, io_req->mem.ptr.bvec);
421 break;
422
423 case DM_IO_VMA:
424 vm_dp_init(dp, io_req->mem.ptr.vma);
425 break;
426
427 case DM_IO_KMEM:
428 km_dp_init(dp, io_req->mem.ptr.addr);
429 break;
430
431 default:
432 return -EINVAL;
433 }
434
435 return 0;
436}
437
438/*
Mikulas Patocka7ff14a32008-04-24 22:10:47 +0100439 * New collapsed (a)synchronous interface.
440 *
441 * If the IO is asynchronous (i.e. it has notify.fn), you must either unplug
442 * the queue with blk_unplug() some time later or set the BIO_RW_SYNC bit in
443 * io_req->bi_rw. If you fail to do one of these, the IO will be submitted to
444 * the disk after q->unplug_delay, which defaults to 3ms in blk-settings.c.
Heinz Mauelshagenc8b03af2007-05-09 02:33:01 -0700445 */
446int dm_io(struct dm_io_request *io_req, unsigned num_regions,
Heinz Mauelshagen22a1ceb2008-04-24 21:43:17 +0100447 struct dm_io_region *where, unsigned long *sync_error_bits)
Heinz Mauelshagenc8b03af2007-05-09 02:33:01 -0700448{
449 int r;
450 struct dpages dp;
451
452 r = dp_init(io_req, &dp);
453 if (r)
454 return r;
455
456 if (!io_req->notify.fn)
457 return sync_io(io_req->client, num_regions, where,
458 io_req->bi_rw, &dp, sync_error_bits);
459
460 return async_io(io_req->client, num_regions, where, io_req->bi_rw,
461 &dp, io_req->notify.fn, io_req->notify.context);
462}
463EXPORT_SYMBOL(dm_io);