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95d402f0 MP |
1 | /* |
2 | * Copyright (C) 2009-2011 Red Hat, Inc. | |
3 | * | |
4 | * Author: Mikulas Patocka <mpatocka@redhat.com> | |
5 | * | |
6 | * This file is released under the GPL. | |
7 | */ | |
8 | ||
9 | #include "dm-bufio.h" | |
10 | ||
11 | #include <linux/device-mapper.h> | |
12 | #include <linux/dm-io.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/vmalloc.h> | |
95d402f0 | 15 | #include <linux/shrinker.h> |
6f66263f | 16 | #include <linux/module.h> |
95d402f0 MP |
17 | |
18 | #define DM_MSG_PREFIX "bufio" | |
19 | ||
20 | /* | |
21 | * Memory management policy: | |
22 | * Limit the number of buffers to DM_BUFIO_MEMORY_PERCENT of main memory | |
23 | * or DM_BUFIO_VMALLOC_PERCENT of vmalloc memory (whichever is lower). | |
24 | * Always allocate at least DM_BUFIO_MIN_BUFFERS buffers. | |
25 | * Start background writeback when there are DM_BUFIO_WRITEBACK_PERCENT | |
26 | * dirty buffers. | |
27 | */ | |
28 | #define DM_BUFIO_MIN_BUFFERS 8 | |
29 | ||
30 | #define DM_BUFIO_MEMORY_PERCENT 2 | |
31 | #define DM_BUFIO_VMALLOC_PERCENT 25 | |
32 | #define DM_BUFIO_WRITEBACK_PERCENT 75 | |
33 | ||
34 | /* | |
35 | * Check buffer ages in this interval (seconds) | |
36 | */ | |
37 | #define DM_BUFIO_WORK_TIMER_SECS 10 | |
38 | ||
39 | /* | |
40 | * Free buffers when they are older than this (seconds) | |
41 | */ | |
42 | #define DM_BUFIO_DEFAULT_AGE_SECS 60 | |
43 | ||
44 | /* | |
45 | * The number of bvec entries that are embedded directly in the buffer. | |
46 | * If the chunk size is larger, dm-io is used to do the io. | |
47 | */ | |
48 | #define DM_BUFIO_INLINE_VECS 16 | |
49 | ||
50 | /* | |
51 | * Buffer hash | |
52 | */ | |
53 | #define DM_BUFIO_HASH_BITS 20 | |
54 | #define DM_BUFIO_HASH(block) \ | |
55 | ((((block) >> DM_BUFIO_HASH_BITS) ^ (block)) & \ | |
56 | ((1 << DM_BUFIO_HASH_BITS) - 1)) | |
57 | ||
58 | /* | |
59 | * Don't try to use kmem_cache_alloc for blocks larger than this. | |
60 | * For explanation, see alloc_buffer_data below. | |
61 | */ | |
62 | #define DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT (PAGE_SIZE >> 1) | |
63 | #define DM_BUFIO_BLOCK_SIZE_GFP_LIMIT (PAGE_SIZE << (MAX_ORDER - 1)) | |
64 | ||
65 | /* | |
66 | * dm_buffer->list_mode | |
67 | */ | |
68 | #define LIST_CLEAN 0 | |
69 | #define LIST_DIRTY 1 | |
70 | #define LIST_SIZE 2 | |
71 | ||
72 | /* | |
73 | * Linking of buffers: | |
74 | * All buffers are linked to cache_hash with their hash_list field. | |
75 | * | |
76 | * Clean buffers that are not being written (B_WRITING not set) | |
77 | * are linked to lru[LIST_CLEAN] with their lru_list field. | |
78 | * | |
79 | * Dirty and clean buffers that are being written are linked to | |
80 | * lru[LIST_DIRTY] with their lru_list field. When the write | |
81 | * finishes, the buffer cannot be relinked immediately (because we | |
82 | * are in an interrupt context and relinking requires process | |
83 | * context), so some clean-not-writing buffers can be held on | |
84 | * dirty_lru too. They are later added to lru in the process | |
85 | * context. | |
86 | */ | |
87 | struct dm_bufio_client { | |
88 | struct mutex lock; | |
89 | ||
90 | struct list_head lru[LIST_SIZE]; | |
91 | unsigned long n_buffers[LIST_SIZE]; | |
92 | ||
93 | struct block_device *bdev; | |
94 | unsigned block_size; | |
95 | unsigned char sectors_per_block_bits; | |
96 | unsigned char pages_per_block_bits; | |
97 | unsigned char blocks_per_page_bits; | |
98 | unsigned aux_size; | |
99 | void (*alloc_callback)(struct dm_buffer *); | |
100 | void (*write_callback)(struct dm_buffer *); | |
101 | ||
102 | struct dm_io_client *dm_io; | |
103 | ||
104 | struct list_head reserved_buffers; | |
105 | unsigned need_reserved_buffers; | |
106 | ||
107 | struct hlist_head *cache_hash; | |
108 | wait_queue_head_t free_buffer_wait; | |
109 | ||
110 | int async_write_error; | |
111 | ||
112 | struct list_head client_list; | |
113 | struct shrinker shrinker; | |
114 | }; | |
115 | ||
116 | /* | |
117 | * Buffer state bits. | |
118 | */ | |
119 | #define B_READING 0 | |
120 | #define B_WRITING 1 | |
121 | #define B_DIRTY 2 | |
122 | ||
123 | /* | |
124 | * Describes how the block was allocated: | |
125 | * kmem_cache_alloc(), __get_free_pages() or vmalloc(). | |
126 | * See the comment at alloc_buffer_data. | |
127 | */ | |
128 | enum data_mode { | |
129 | DATA_MODE_SLAB = 0, | |
130 | DATA_MODE_GET_FREE_PAGES = 1, | |
131 | DATA_MODE_VMALLOC = 2, | |
132 | DATA_MODE_LIMIT = 3 | |
133 | }; | |
134 | ||
135 | struct dm_buffer { | |
136 | struct hlist_node hash_list; | |
137 | struct list_head lru_list; | |
138 | sector_t block; | |
139 | void *data; | |
140 | enum data_mode data_mode; | |
141 | unsigned char list_mode; /* LIST_* */ | |
142 | unsigned hold_count; | |
143 | int read_error; | |
144 | int write_error; | |
145 | unsigned long state; | |
146 | unsigned long last_accessed; | |
147 | struct dm_bufio_client *c; | |
2480945c | 148 | struct list_head write_list; |
95d402f0 MP |
149 | struct bio bio; |
150 | struct bio_vec bio_vec[DM_BUFIO_INLINE_VECS]; | |
151 | }; | |
152 | ||
153 | /*----------------------------------------------------------------*/ | |
154 | ||
155 | static struct kmem_cache *dm_bufio_caches[PAGE_SHIFT - SECTOR_SHIFT]; | |
156 | static char *dm_bufio_cache_names[PAGE_SHIFT - SECTOR_SHIFT]; | |
157 | ||
158 | static inline int dm_bufio_cache_index(struct dm_bufio_client *c) | |
159 | { | |
160 | unsigned ret = c->blocks_per_page_bits - 1; | |
161 | ||
162 | BUG_ON(ret >= ARRAY_SIZE(dm_bufio_caches)); | |
163 | ||
164 | return ret; | |
165 | } | |
166 | ||
167 | #define DM_BUFIO_CACHE(c) (dm_bufio_caches[dm_bufio_cache_index(c)]) | |
168 | #define DM_BUFIO_CACHE_NAME(c) (dm_bufio_cache_names[dm_bufio_cache_index(c)]) | |
169 | ||
170 | #define dm_bufio_in_request() (!!current->bio_list) | |
171 | ||
172 | static void dm_bufio_lock(struct dm_bufio_client *c) | |
173 | { | |
174 | mutex_lock_nested(&c->lock, dm_bufio_in_request()); | |
175 | } | |
176 | ||
177 | static int dm_bufio_trylock(struct dm_bufio_client *c) | |
178 | { | |
179 | return mutex_trylock(&c->lock); | |
180 | } | |
181 | ||
182 | static void dm_bufio_unlock(struct dm_bufio_client *c) | |
183 | { | |
184 | mutex_unlock(&c->lock); | |
185 | } | |
186 | ||
187 | /* | |
188 | * FIXME Move to sched.h? | |
189 | */ | |
190 | #ifdef CONFIG_PREEMPT_VOLUNTARY | |
191 | # define dm_bufio_cond_resched() \ | |
192 | do { \ | |
193 | if (unlikely(need_resched())) \ | |
194 | _cond_resched(); \ | |
195 | } while (0) | |
196 | #else | |
197 | # define dm_bufio_cond_resched() do { } while (0) | |
198 | #endif | |
199 | ||
200 | /*----------------------------------------------------------------*/ | |
201 | ||
202 | /* | |
203 | * Default cache size: available memory divided by the ratio. | |
204 | */ | |
205 | static unsigned long dm_bufio_default_cache_size; | |
206 | ||
207 | /* | |
208 | * Total cache size set by the user. | |
209 | */ | |
210 | static unsigned long dm_bufio_cache_size; | |
211 | ||
212 | /* | |
213 | * A copy of dm_bufio_cache_size because dm_bufio_cache_size can change | |
214 | * at any time. If it disagrees, the user has changed cache size. | |
215 | */ | |
216 | static unsigned long dm_bufio_cache_size_latch; | |
217 | ||
218 | static DEFINE_SPINLOCK(param_spinlock); | |
219 | ||
220 | /* | |
221 | * Buffers are freed after this timeout | |
222 | */ | |
223 | static unsigned dm_bufio_max_age = DM_BUFIO_DEFAULT_AGE_SECS; | |
224 | ||
225 | static unsigned long dm_bufio_peak_allocated; | |
226 | static unsigned long dm_bufio_allocated_kmem_cache; | |
227 | static unsigned long dm_bufio_allocated_get_free_pages; | |
228 | static unsigned long dm_bufio_allocated_vmalloc; | |
229 | static unsigned long dm_bufio_current_allocated; | |
230 | ||
231 | /*----------------------------------------------------------------*/ | |
232 | ||
233 | /* | |
234 | * Per-client cache: dm_bufio_cache_size / dm_bufio_client_count | |
235 | */ | |
236 | static unsigned long dm_bufio_cache_size_per_client; | |
237 | ||
238 | /* | |
239 | * The current number of clients. | |
240 | */ | |
241 | static int dm_bufio_client_count; | |
242 | ||
243 | /* | |
244 | * The list of all clients. | |
245 | */ | |
246 | static LIST_HEAD(dm_bufio_all_clients); | |
247 | ||
248 | /* | |
249 | * This mutex protects dm_bufio_cache_size_latch, | |
250 | * dm_bufio_cache_size_per_client and dm_bufio_client_count | |
251 | */ | |
252 | static DEFINE_MUTEX(dm_bufio_clients_lock); | |
253 | ||
254 | /*----------------------------------------------------------------*/ | |
255 | ||
256 | static void adjust_total_allocated(enum data_mode data_mode, long diff) | |
257 | { | |
258 | static unsigned long * const class_ptr[DATA_MODE_LIMIT] = { | |
259 | &dm_bufio_allocated_kmem_cache, | |
260 | &dm_bufio_allocated_get_free_pages, | |
261 | &dm_bufio_allocated_vmalloc, | |
262 | }; | |
263 | ||
264 | spin_lock(¶m_spinlock); | |
265 | ||
266 | *class_ptr[data_mode] += diff; | |
267 | ||
268 | dm_bufio_current_allocated += diff; | |
269 | ||
270 | if (dm_bufio_current_allocated > dm_bufio_peak_allocated) | |
271 | dm_bufio_peak_allocated = dm_bufio_current_allocated; | |
272 | ||
273 | spin_unlock(¶m_spinlock); | |
274 | } | |
275 | ||
276 | /* | |
277 | * Change the number of clients and recalculate per-client limit. | |
278 | */ | |
279 | static void __cache_size_refresh(void) | |
280 | { | |
281 | BUG_ON(!mutex_is_locked(&dm_bufio_clients_lock)); | |
282 | BUG_ON(dm_bufio_client_count < 0); | |
283 | ||
fe5fe906 | 284 | dm_bufio_cache_size_latch = ACCESS_ONCE(dm_bufio_cache_size); |
95d402f0 MP |
285 | |
286 | /* | |
287 | * Use default if set to 0 and report the actual cache size used. | |
288 | */ | |
289 | if (!dm_bufio_cache_size_latch) { | |
290 | (void)cmpxchg(&dm_bufio_cache_size, 0, | |
291 | dm_bufio_default_cache_size); | |
292 | dm_bufio_cache_size_latch = dm_bufio_default_cache_size; | |
293 | } | |
294 | ||
295 | dm_bufio_cache_size_per_client = dm_bufio_cache_size_latch / | |
296 | (dm_bufio_client_count ? : 1); | |
297 | } | |
298 | ||
299 | /* | |
300 | * Allocating buffer data. | |
301 | * | |
302 | * Small buffers are allocated with kmem_cache, to use space optimally. | |
303 | * | |
304 | * For large buffers, we choose between get_free_pages and vmalloc. | |
305 | * Each has advantages and disadvantages. | |
306 | * | |
307 | * __get_free_pages can randomly fail if the memory is fragmented. | |
308 | * __vmalloc won't randomly fail, but vmalloc space is limited (it may be | |
309 | * as low as 128M) so using it for caching is not appropriate. | |
310 | * | |
311 | * If the allocation may fail we use __get_free_pages. Memory fragmentation | |
312 | * won't have a fatal effect here, but it just causes flushes of some other | |
313 | * buffers and more I/O will be performed. Don't use __get_free_pages if it | |
314 | * always fails (i.e. order >= MAX_ORDER). | |
315 | * | |
316 | * If the allocation shouldn't fail we use __vmalloc. This is only for the | |
317 | * initial reserve allocation, so there's no risk of wasting all vmalloc | |
318 | * space. | |
319 | */ | |
320 | static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask, | |
321 | enum data_mode *data_mode) | |
322 | { | |
502624bd MP |
323 | unsigned noio_flag; |
324 | void *ptr; | |
325 | ||
95d402f0 MP |
326 | if (c->block_size <= DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT) { |
327 | *data_mode = DATA_MODE_SLAB; | |
328 | return kmem_cache_alloc(DM_BUFIO_CACHE(c), gfp_mask); | |
329 | } | |
330 | ||
331 | if (c->block_size <= DM_BUFIO_BLOCK_SIZE_GFP_LIMIT && | |
332 | gfp_mask & __GFP_NORETRY) { | |
333 | *data_mode = DATA_MODE_GET_FREE_PAGES; | |
334 | return (void *)__get_free_pages(gfp_mask, | |
335 | c->pages_per_block_bits); | |
336 | } | |
337 | ||
338 | *data_mode = DATA_MODE_VMALLOC; | |
502624bd MP |
339 | |
340 | /* | |
341 | * __vmalloc allocates the data pages and auxiliary structures with | |
342 | * gfp_flags that were specified, but pagetables are always allocated | |
343 | * with GFP_KERNEL, no matter what was specified as gfp_mask. | |
344 | * | |
345 | * Consequently, we must set per-process flag PF_MEMALLOC_NOIO so that | |
346 | * all allocations done by this process (including pagetables) are done | |
347 | * as if GFP_NOIO was specified. | |
348 | */ | |
349 | ||
350 | if (gfp_mask & __GFP_NORETRY) | |
351 | noio_flag = memalloc_noio_save(); | |
352 | ||
220cd058 | 353 | ptr = __vmalloc(c->block_size, gfp_mask | __GFP_HIGHMEM, PAGE_KERNEL); |
502624bd MP |
354 | |
355 | if (gfp_mask & __GFP_NORETRY) | |
356 | memalloc_noio_restore(noio_flag); | |
357 | ||
358 | return ptr; | |
95d402f0 MP |
359 | } |
360 | ||
361 | /* | |
362 | * Free buffer's data. | |
363 | */ | |
364 | static void free_buffer_data(struct dm_bufio_client *c, | |
365 | void *data, enum data_mode data_mode) | |
366 | { | |
367 | switch (data_mode) { | |
368 | case DATA_MODE_SLAB: | |
369 | kmem_cache_free(DM_BUFIO_CACHE(c), data); | |
370 | break; | |
371 | ||
372 | case DATA_MODE_GET_FREE_PAGES: | |
373 | free_pages((unsigned long)data, c->pages_per_block_bits); | |
374 | break; | |
375 | ||
376 | case DATA_MODE_VMALLOC: | |
377 | vfree(data); | |
378 | break; | |
379 | ||
380 | default: | |
381 | DMCRIT("dm_bufio_free_buffer_data: bad data mode: %d", | |
382 | data_mode); | |
383 | BUG(); | |
384 | } | |
385 | } | |
386 | ||
387 | /* | |
388 | * Allocate buffer and its data. | |
389 | */ | |
390 | static struct dm_buffer *alloc_buffer(struct dm_bufio_client *c, gfp_t gfp_mask) | |
391 | { | |
392 | struct dm_buffer *b = kmalloc(sizeof(struct dm_buffer) + c->aux_size, | |
393 | gfp_mask); | |
394 | ||
395 | if (!b) | |
396 | return NULL; | |
397 | ||
398 | b->c = c; | |
399 | ||
400 | b->data = alloc_buffer_data(c, gfp_mask, &b->data_mode); | |
401 | if (!b->data) { | |
402 | kfree(b); | |
403 | return NULL; | |
404 | } | |
405 | ||
406 | adjust_total_allocated(b->data_mode, (long)c->block_size); | |
407 | ||
408 | return b; | |
409 | } | |
410 | ||
411 | /* | |
412 | * Free buffer and its data. | |
413 | */ | |
414 | static void free_buffer(struct dm_buffer *b) | |
415 | { | |
416 | struct dm_bufio_client *c = b->c; | |
417 | ||
418 | adjust_total_allocated(b->data_mode, -(long)c->block_size); | |
419 | ||
420 | free_buffer_data(c, b->data, b->data_mode); | |
421 | kfree(b); | |
422 | } | |
423 | ||
424 | /* | |
425 | * Link buffer to the hash list and clean or dirty queue. | |
426 | */ | |
427 | static void __link_buffer(struct dm_buffer *b, sector_t block, int dirty) | |
428 | { | |
429 | struct dm_bufio_client *c = b->c; | |
430 | ||
431 | c->n_buffers[dirty]++; | |
432 | b->block = block; | |
433 | b->list_mode = dirty; | |
434 | list_add(&b->lru_list, &c->lru[dirty]); | |
435 | hlist_add_head(&b->hash_list, &c->cache_hash[DM_BUFIO_HASH(block)]); | |
436 | b->last_accessed = jiffies; | |
437 | } | |
438 | ||
439 | /* | |
440 | * Unlink buffer from the hash list and dirty or clean queue. | |
441 | */ | |
442 | static void __unlink_buffer(struct dm_buffer *b) | |
443 | { | |
444 | struct dm_bufio_client *c = b->c; | |
445 | ||
446 | BUG_ON(!c->n_buffers[b->list_mode]); | |
447 | ||
448 | c->n_buffers[b->list_mode]--; | |
449 | hlist_del(&b->hash_list); | |
450 | list_del(&b->lru_list); | |
451 | } | |
452 | ||
453 | /* | |
454 | * Place the buffer to the head of dirty or clean LRU queue. | |
455 | */ | |
456 | static void __relink_lru(struct dm_buffer *b, int dirty) | |
457 | { | |
458 | struct dm_bufio_client *c = b->c; | |
459 | ||
460 | BUG_ON(!c->n_buffers[b->list_mode]); | |
461 | ||
462 | c->n_buffers[b->list_mode]--; | |
463 | c->n_buffers[dirty]++; | |
464 | b->list_mode = dirty; | |
54499afb | 465 | list_move(&b->lru_list, &c->lru[dirty]); |
95d402f0 MP |
466 | } |
467 | ||
468 | /*---------------------------------------------------------------- | |
469 | * Submit I/O on the buffer. | |
470 | * | |
471 | * Bio interface is faster but it has some problems: | |
472 | * the vector list is limited (increasing this limit increases | |
473 | * memory-consumption per buffer, so it is not viable); | |
474 | * | |
475 | * the memory must be direct-mapped, not vmalloced; | |
476 | * | |
477 | * the I/O driver can reject requests spuriously if it thinks that | |
478 | * the requests are too big for the device or if they cross a | |
479 | * controller-defined memory boundary. | |
480 | * | |
481 | * If the buffer is small enough (up to DM_BUFIO_INLINE_VECS pages) and | |
482 | * it is not vmalloced, try using the bio interface. | |
483 | * | |
484 | * If the buffer is big, if it is vmalloced or if the underlying device | |
485 | * rejects the bio because it is too large, use dm-io layer to do the I/O. | |
486 | * The dm-io layer splits the I/O into multiple requests, avoiding the above | |
487 | * shortcomings. | |
488 | *--------------------------------------------------------------*/ | |
489 | ||
490 | /* | |
491 | * dm-io completion routine. It just calls b->bio.bi_end_io, pretending | |
492 | * that the request was handled directly with bio interface. | |
493 | */ | |
494 | static void dmio_complete(unsigned long error, void *context) | |
495 | { | |
496 | struct dm_buffer *b = context; | |
497 | ||
498 | b->bio.bi_end_io(&b->bio, error ? -EIO : 0); | |
499 | } | |
500 | ||
501 | static void use_dmio(struct dm_buffer *b, int rw, sector_t block, | |
502 | bio_end_io_t *end_io) | |
503 | { | |
504 | int r; | |
505 | struct dm_io_request io_req = { | |
506 | .bi_rw = rw, | |
507 | .notify.fn = dmio_complete, | |
508 | .notify.context = b, | |
509 | .client = b->c->dm_io, | |
510 | }; | |
511 | struct dm_io_region region = { | |
512 | .bdev = b->c->bdev, | |
513 | .sector = block << b->c->sectors_per_block_bits, | |
514 | .count = b->c->block_size >> SECTOR_SHIFT, | |
515 | }; | |
516 | ||
517 | if (b->data_mode != DATA_MODE_VMALLOC) { | |
518 | io_req.mem.type = DM_IO_KMEM; | |
519 | io_req.mem.ptr.addr = b->data; | |
520 | } else { | |
521 | io_req.mem.type = DM_IO_VMA; | |
522 | io_req.mem.ptr.vma = b->data; | |
523 | } | |
524 | ||
525 | b->bio.bi_end_io = end_io; | |
526 | ||
527 | r = dm_io(&io_req, 1, ®ion, NULL); | |
528 | if (r) | |
529 | end_io(&b->bio, r); | |
530 | } | |
531 | ||
532 | static void use_inline_bio(struct dm_buffer *b, int rw, sector_t block, | |
533 | bio_end_io_t *end_io) | |
534 | { | |
535 | char *ptr; | |
536 | int len; | |
537 | ||
538 | bio_init(&b->bio); | |
539 | b->bio.bi_io_vec = b->bio_vec; | |
540 | b->bio.bi_max_vecs = DM_BUFIO_INLINE_VECS; | |
541 | b->bio.bi_sector = block << b->c->sectors_per_block_bits; | |
542 | b->bio.bi_bdev = b->c->bdev; | |
543 | b->bio.bi_end_io = end_io; | |
544 | ||
545 | /* | |
546 | * We assume that if len >= PAGE_SIZE ptr is page-aligned. | |
547 | * If len < PAGE_SIZE the buffer doesn't cross page boundary. | |
548 | */ | |
549 | ptr = b->data; | |
550 | len = b->c->block_size; | |
551 | ||
552 | if (len >= PAGE_SIZE) | |
553 | BUG_ON((unsigned long)ptr & (PAGE_SIZE - 1)); | |
554 | else | |
555 | BUG_ON((unsigned long)ptr & (len - 1)); | |
556 | ||
557 | do { | |
558 | if (!bio_add_page(&b->bio, virt_to_page(ptr), | |
559 | len < PAGE_SIZE ? len : PAGE_SIZE, | |
560 | virt_to_phys(ptr) & (PAGE_SIZE - 1))) { | |
561 | BUG_ON(b->c->block_size <= PAGE_SIZE); | |
562 | use_dmio(b, rw, block, end_io); | |
563 | return; | |
564 | } | |
565 | ||
566 | len -= PAGE_SIZE; | |
567 | ptr += PAGE_SIZE; | |
568 | } while (len > 0); | |
569 | ||
570 | submit_bio(rw, &b->bio); | |
571 | } | |
572 | ||
573 | static void submit_io(struct dm_buffer *b, int rw, sector_t block, | |
574 | bio_end_io_t *end_io) | |
575 | { | |
576 | if (rw == WRITE && b->c->write_callback) | |
577 | b->c->write_callback(b); | |
578 | ||
579 | if (b->c->block_size <= DM_BUFIO_INLINE_VECS * PAGE_SIZE && | |
580 | b->data_mode != DATA_MODE_VMALLOC) | |
581 | use_inline_bio(b, rw, block, end_io); | |
582 | else | |
583 | use_dmio(b, rw, block, end_io); | |
584 | } | |
585 | ||
586 | /*---------------------------------------------------------------- | |
587 | * Writing dirty buffers | |
588 | *--------------------------------------------------------------*/ | |
589 | ||
590 | /* | |
591 | * The endio routine for write. | |
592 | * | |
593 | * Set the error, clear B_WRITING bit and wake anyone who was waiting on | |
594 | * it. | |
595 | */ | |
596 | static void write_endio(struct bio *bio, int error) | |
597 | { | |
598 | struct dm_buffer *b = container_of(bio, struct dm_buffer, bio); | |
599 | ||
600 | b->write_error = error; | |
a66cc28f | 601 | if (unlikely(error)) { |
95d402f0 MP |
602 | struct dm_bufio_client *c = b->c; |
603 | (void)cmpxchg(&c->async_write_error, 0, error); | |
604 | } | |
605 | ||
606 | BUG_ON(!test_bit(B_WRITING, &b->state)); | |
607 | ||
608 | smp_mb__before_clear_bit(); | |
609 | clear_bit(B_WRITING, &b->state); | |
610 | smp_mb__after_clear_bit(); | |
611 | ||
612 | wake_up_bit(&b->state, B_WRITING); | |
613 | } | |
614 | ||
615 | /* | |
616 | * This function is called when wait_on_bit is actually waiting. | |
617 | */ | |
618 | static int do_io_schedule(void *word) | |
619 | { | |
620 | io_schedule(); | |
621 | ||
622 | return 0; | |
623 | } | |
624 | ||
625 | /* | |
626 | * Initiate a write on a dirty buffer, but don't wait for it. | |
627 | * | |
628 | * - If the buffer is not dirty, exit. | |
629 | * - If there some previous write going on, wait for it to finish (we can't | |
630 | * have two writes on the same buffer simultaneously). | |
631 | * - Submit our write and don't wait on it. We set B_WRITING indicating | |
632 | * that there is a write in progress. | |
633 | */ | |
2480945c MP |
634 | static void __write_dirty_buffer(struct dm_buffer *b, |
635 | struct list_head *write_list) | |
95d402f0 MP |
636 | { |
637 | if (!test_bit(B_DIRTY, &b->state)) | |
638 | return; | |
639 | ||
640 | clear_bit(B_DIRTY, &b->state); | |
641 | wait_on_bit_lock(&b->state, B_WRITING, | |
642 | do_io_schedule, TASK_UNINTERRUPTIBLE); | |
643 | ||
2480945c MP |
644 | if (!write_list) |
645 | submit_io(b, WRITE, b->block, write_endio); | |
646 | else | |
647 | list_add_tail(&b->write_list, write_list); | |
648 | } | |
649 | ||
650 | static void __flush_write_list(struct list_head *write_list) | |
651 | { | |
652 | struct blk_plug plug; | |
653 | blk_start_plug(&plug); | |
654 | while (!list_empty(write_list)) { | |
655 | struct dm_buffer *b = | |
656 | list_entry(write_list->next, struct dm_buffer, write_list); | |
657 | list_del(&b->write_list); | |
658 | submit_io(b, WRITE, b->block, write_endio); | |
659 | dm_bufio_cond_resched(); | |
660 | } | |
661 | blk_finish_plug(&plug); | |
95d402f0 MP |
662 | } |
663 | ||
664 | /* | |
665 | * Wait until any activity on the buffer finishes. Possibly write the | |
666 | * buffer if it is dirty. When this function finishes, there is no I/O | |
667 | * running on the buffer and the buffer is not dirty. | |
668 | */ | |
669 | static void __make_buffer_clean(struct dm_buffer *b) | |
670 | { | |
671 | BUG_ON(b->hold_count); | |
672 | ||
673 | if (!b->state) /* fast case */ | |
674 | return; | |
675 | ||
676 | wait_on_bit(&b->state, B_READING, do_io_schedule, TASK_UNINTERRUPTIBLE); | |
2480945c | 677 | __write_dirty_buffer(b, NULL); |
95d402f0 MP |
678 | wait_on_bit(&b->state, B_WRITING, do_io_schedule, TASK_UNINTERRUPTIBLE); |
679 | } | |
680 | ||
681 | /* | |
682 | * Find some buffer that is not held by anybody, clean it, unlink it and | |
683 | * return it. | |
684 | */ | |
685 | static struct dm_buffer *__get_unclaimed_buffer(struct dm_bufio_client *c) | |
686 | { | |
687 | struct dm_buffer *b; | |
688 | ||
689 | list_for_each_entry_reverse(b, &c->lru[LIST_CLEAN], lru_list) { | |
690 | BUG_ON(test_bit(B_WRITING, &b->state)); | |
691 | BUG_ON(test_bit(B_DIRTY, &b->state)); | |
692 | ||
693 | if (!b->hold_count) { | |
694 | __make_buffer_clean(b); | |
695 | __unlink_buffer(b); | |
696 | return b; | |
697 | } | |
698 | dm_bufio_cond_resched(); | |
699 | } | |
700 | ||
701 | list_for_each_entry_reverse(b, &c->lru[LIST_DIRTY], lru_list) { | |
702 | BUG_ON(test_bit(B_READING, &b->state)); | |
703 | ||
704 | if (!b->hold_count) { | |
705 | __make_buffer_clean(b); | |
706 | __unlink_buffer(b); | |
707 | return b; | |
708 | } | |
709 | dm_bufio_cond_resched(); | |
710 | } | |
711 | ||
712 | return NULL; | |
713 | } | |
714 | ||
715 | /* | |
716 | * Wait until some other threads free some buffer or release hold count on | |
717 | * some buffer. | |
718 | * | |
719 | * This function is entered with c->lock held, drops it and regains it | |
720 | * before exiting. | |
721 | */ | |
722 | static void __wait_for_free_buffer(struct dm_bufio_client *c) | |
723 | { | |
724 | DECLARE_WAITQUEUE(wait, current); | |
725 | ||
726 | add_wait_queue(&c->free_buffer_wait, &wait); | |
727 | set_task_state(current, TASK_UNINTERRUPTIBLE); | |
728 | dm_bufio_unlock(c); | |
729 | ||
730 | io_schedule(); | |
731 | ||
732 | set_task_state(current, TASK_RUNNING); | |
733 | remove_wait_queue(&c->free_buffer_wait, &wait); | |
734 | ||
735 | dm_bufio_lock(c); | |
736 | } | |
737 | ||
a66cc28f MP |
738 | enum new_flag { |
739 | NF_FRESH = 0, | |
740 | NF_READ = 1, | |
741 | NF_GET = 2, | |
742 | NF_PREFETCH = 3 | |
743 | }; | |
744 | ||
95d402f0 MP |
745 | /* |
746 | * Allocate a new buffer. If the allocation is not possible, wait until | |
747 | * some other thread frees a buffer. | |
748 | * | |
749 | * May drop the lock and regain it. | |
750 | */ | |
a66cc28f | 751 | static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client *c, enum new_flag nf) |
95d402f0 MP |
752 | { |
753 | struct dm_buffer *b; | |
754 | ||
755 | /* | |
756 | * dm-bufio is resistant to allocation failures (it just keeps | |
757 | * one buffer reserved in cases all the allocations fail). | |
758 | * So set flags to not try too hard: | |
759 | * GFP_NOIO: don't recurse into the I/O layer | |
760 | * __GFP_NORETRY: don't retry and rather return failure | |
761 | * __GFP_NOMEMALLOC: don't use emergency reserves | |
762 | * __GFP_NOWARN: don't print a warning in case of failure | |
763 | * | |
764 | * For debugging, if we set the cache size to 1, no new buffers will | |
765 | * be allocated. | |
766 | */ | |
767 | while (1) { | |
768 | if (dm_bufio_cache_size_latch != 1) { | |
769 | b = alloc_buffer(c, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); | |
770 | if (b) | |
771 | return b; | |
772 | } | |
773 | ||
a66cc28f MP |
774 | if (nf == NF_PREFETCH) |
775 | return NULL; | |
776 | ||
95d402f0 MP |
777 | if (!list_empty(&c->reserved_buffers)) { |
778 | b = list_entry(c->reserved_buffers.next, | |
779 | struct dm_buffer, lru_list); | |
780 | list_del(&b->lru_list); | |
781 | c->need_reserved_buffers++; | |
782 | ||
783 | return b; | |
784 | } | |
785 | ||
786 | b = __get_unclaimed_buffer(c); | |
787 | if (b) | |
788 | return b; | |
789 | ||
790 | __wait_for_free_buffer(c); | |
791 | } | |
792 | } | |
793 | ||
a66cc28f | 794 | static struct dm_buffer *__alloc_buffer_wait(struct dm_bufio_client *c, enum new_flag nf) |
95d402f0 | 795 | { |
a66cc28f MP |
796 | struct dm_buffer *b = __alloc_buffer_wait_no_callback(c, nf); |
797 | ||
798 | if (!b) | |
799 | return NULL; | |
95d402f0 MP |
800 | |
801 | if (c->alloc_callback) | |
802 | c->alloc_callback(b); | |
803 | ||
804 | return b; | |
805 | } | |
806 | ||
807 | /* | |
808 | * Free a buffer and wake other threads waiting for free buffers. | |
809 | */ | |
810 | static void __free_buffer_wake(struct dm_buffer *b) | |
811 | { | |
812 | struct dm_bufio_client *c = b->c; | |
813 | ||
814 | if (!c->need_reserved_buffers) | |
815 | free_buffer(b); | |
816 | else { | |
817 | list_add(&b->lru_list, &c->reserved_buffers); | |
818 | c->need_reserved_buffers--; | |
819 | } | |
820 | ||
821 | wake_up(&c->free_buffer_wait); | |
822 | } | |
823 | ||
2480945c MP |
824 | static void __write_dirty_buffers_async(struct dm_bufio_client *c, int no_wait, |
825 | struct list_head *write_list) | |
95d402f0 MP |
826 | { |
827 | struct dm_buffer *b, *tmp; | |
828 | ||
829 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { | |
830 | BUG_ON(test_bit(B_READING, &b->state)); | |
831 | ||
832 | if (!test_bit(B_DIRTY, &b->state) && | |
833 | !test_bit(B_WRITING, &b->state)) { | |
834 | __relink_lru(b, LIST_CLEAN); | |
835 | continue; | |
836 | } | |
837 | ||
838 | if (no_wait && test_bit(B_WRITING, &b->state)) | |
839 | return; | |
840 | ||
2480945c | 841 | __write_dirty_buffer(b, write_list); |
95d402f0 MP |
842 | dm_bufio_cond_resched(); |
843 | } | |
844 | } | |
845 | ||
846 | /* | |
847 | * Get writeback threshold and buffer limit for a given client. | |
848 | */ | |
849 | static void __get_memory_limit(struct dm_bufio_client *c, | |
850 | unsigned long *threshold_buffers, | |
851 | unsigned long *limit_buffers) | |
852 | { | |
853 | unsigned long buffers; | |
854 | ||
fe5fe906 | 855 | if (ACCESS_ONCE(dm_bufio_cache_size) != dm_bufio_cache_size_latch) { |
95d402f0 MP |
856 | mutex_lock(&dm_bufio_clients_lock); |
857 | __cache_size_refresh(); | |
858 | mutex_unlock(&dm_bufio_clients_lock); | |
859 | } | |
860 | ||
861 | buffers = dm_bufio_cache_size_per_client >> | |
862 | (c->sectors_per_block_bits + SECTOR_SHIFT); | |
863 | ||
864 | if (buffers < DM_BUFIO_MIN_BUFFERS) | |
865 | buffers = DM_BUFIO_MIN_BUFFERS; | |
866 | ||
867 | *limit_buffers = buffers; | |
868 | *threshold_buffers = buffers * DM_BUFIO_WRITEBACK_PERCENT / 100; | |
869 | } | |
870 | ||
871 | /* | |
872 | * Check if we're over watermark. | |
873 | * If we are over threshold_buffers, start freeing buffers. | |
874 | * If we're over "limit_buffers", block until we get under the limit. | |
875 | */ | |
2480945c MP |
876 | static void __check_watermark(struct dm_bufio_client *c, |
877 | struct list_head *write_list) | |
95d402f0 MP |
878 | { |
879 | unsigned long threshold_buffers, limit_buffers; | |
880 | ||
881 | __get_memory_limit(c, &threshold_buffers, &limit_buffers); | |
882 | ||
883 | while (c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY] > | |
884 | limit_buffers) { | |
885 | ||
886 | struct dm_buffer *b = __get_unclaimed_buffer(c); | |
887 | ||
888 | if (!b) | |
889 | return; | |
890 | ||
891 | __free_buffer_wake(b); | |
892 | dm_bufio_cond_resched(); | |
893 | } | |
894 | ||
895 | if (c->n_buffers[LIST_DIRTY] > threshold_buffers) | |
2480945c | 896 | __write_dirty_buffers_async(c, 1, write_list); |
95d402f0 MP |
897 | } |
898 | ||
899 | /* | |
900 | * Find a buffer in the hash. | |
901 | */ | |
902 | static struct dm_buffer *__find(struct dm_bufio_client *c, sector_t block) | |
903 | { | |
904 | struct dm_buffer *b; | |
95d402f0 | 905 | |
b67bfe0d | 906 | hlist_for_each_entry(b, &c->cache_hash[DM_BUFIO_HASH(block)], |
95d402f0 MP |
907 | hash_list) { |
908 | dm_bufio_cond_resched(); | |
909 | if (b->block == block) | |
910 | return b; | |
911 | } | |
912 | ||
913 | return NULL; | |
914 | } | |
915 | ||
916 | /*---------------------------------------------------------------- | |
917 | * Getting a buffer | |
918 | *--------------------------------------------------------------*/ | |
919 | ||
95d402f0 | 920 | static struct dm_buffer *__bufio_new(struct dm_bufio_client *c, sector_t block, |
2480945c MP |
921 | enum new_flag nf, int *need_submit, |
922 | struct list_head *write_list) | |
95d402f0 MP |
923 | { |
924 | struct dm_buffer *b, *new_b = NULL; | |
925 | ||
926 | *need_submit = 0; | |
927 | ||
928 | b = __find(c, block); | |
a66cc28f MP |
929 | if (b) |
930 | goto found_buffer; | |
95d402f0 MP |
931 | |
932 | if (nf == NF_GET) | |
933 | return NULL; | |
934 | ||
a66cc28f MP |
935 | new_b = __alloc_buffer_wait(c, nf); |
936 | if (!new_b) | |
937 | return NULL; | |
95d402f0 MP |
938 | |
939 | /* | |
940 | * We've had a period where the mutex was unlocked, so need to | |
941 | * recheck the hash table. | |
942 | */ | |
943 | b = __find(c, block); | |
944 | if (b) { | |
945 | __free_buffer_wake(new_b); | |
a66cc28f | 946 | goto found_buffer; |
95d402f0 MP |
947 | } |
948 | ||
2480945c | 949 | __check_watermark(c, write_list); |
95d402f0 MP |
950 | |
951 | b = new_b; | |
952 | b->hold_count = 1; | |
953 | b->read_error = 0; | |
954 | b->write_error = 0; | |
955 | __link_buffer(b, block, LIST_CLEAN); | |
956 | ||
957 | if (nf == NF_FRESH) { | |
958 | b->state = 0; | |
959 | return b; | |
960 | } | |
961 | ||
962 | b->state = 1 << B_READING; | |
963 | *need_submit = 1; | |
964 | ||
965 | return b; | |
a66cc28f MP |
966 | |
967 | found_buffer: | |
968 | if (nf == NF_PREFETCH) | |
969 | return NULL; | |
970 | /* | |
971 | * Note: it is essential that we don't wait for the buffer to be | |
972 | * read if dm_bufio_get function is used. Both dm_bufio_get and | |
973 | * dm_bufio_prefetch can be used in the driver request routine. | |
974 | * If the user called both dm_bufio_prefetch and dm_bufio_get on | |
975 | * the same buffer, it would deadlock if we waited. | |
976 | */ | |
977 | if (nf == NF_GET && unlikely(test_bit(B_READING, &b->state))) | |
978 | return NULL; | |
979 | ||
980 | b->hold_count++; | |
981 | __relink_lru(b, test_bit(B_DIRTY, &b->state) || | |
982 | test_bit(B_WRITING, &b->state)); | |
983 | return b; | |
95d402f0 MP |
984 | } |
985 | ||
986 | /* | |
987 | * The endio routine for reading: set the error, clear the bit and wake up | |
988 | * anyone waiting on the buffer. | |
989 | */ | |
990 | static void read_endio(struct bio *bio, int error) | |
991 | { | |
992 | struct dm_buffer *b = container_of(bio, struct dm_buffer, bio); | |
993 | ||
994 | b->read_error = error; | |
995 | ||
996 | BUG_ON(!test_bit(B_READING, &b->state)); | |
997 | ||
998 | smp_mb__before_clear_bit(); | |
999 | clear_bit(B_READING, &b->state); | |
1000 | smp_mb__after_clear_bit(); | |
1001 | ||
1002 | wake_up_bit(&b->state, B_READING); | |
1003 | } | |
1004 | ||
1005 | /* | |
1006 | * A common routine for dm_bufio_new and dm_bufio_read. Operation of these | |
1007 | * functions is similar except that dm_bufio_new doesn't read the | |
1008 | * buffer from the disk (assuming that the caller overwrites all the data | |
1009 | * and uses dm_bufio_mark_buffer_dirty to write new data back). | |
1010 | */ | |
1011 | static void *new_read(struct dm_bufio_client *c, sector_t block, | |
1012 | enum new_flag nf, struct dm_buffer **bp) | |
1013 | { | |
1014 | int need_submit; | |
1015 | struct dm_buffer *b; | |
1016 | ||
2480945c MP |
1017 | LIST_HEAD(write_list); |
1018 | ||
95d402f0 | 1019 | dm_bufio_lock(c); |
2480945c | 1020 | b = __bufio_new(c, block, nf, &need_submit, &write_list); |
95d402f0 MP |
1021 | dm_bufio_unlock(c); |
1022 | ||
2480945c MP |
1023 | __flush_write_list(&write_list); |
1024 | ||
a66cc28f | 1025 | if (!b) |
95d402f0 MP |
1026 | return b; |
1027 | ||
1028 | if (need_submit) | |
1029 | submit_io(b, READ, b->block, read_endio); | |
1030 | ||
1031 | wait_on_bit(&b->state, B_READING, do_io_schedule, TASK_UNINTERRUPTIBLE); | |
1032 | ||
1033 | if (b->read_error) { | |
1034 | int error = b->read_error; | |
1035 | ||
1036 | dm_bufio_release(b); | |
1037 | ||
1038 | return ERR_PTR(error); | |
1039 | } | |
1040 | ||
1041 | *bp = b; | |
1042 | ||
1043 | return b->data; | |
1044 | } | |
1045 | ||
1046 | void *dm_bufio_get(struct dm_bufio_client *c, sector_t block, | |
1047 | struct dm_buffer **bp) | |
1048 | { | |
1049 | return new_read(c, block, NF_GET, bp); | |
1050 | } | |
1051 | EXPORT_SYMBOL_GPL(dm_bufio_get); | |
1052 | ||
1053 | void *dm_bufio_read(struct dm_bufio_client *c, sector_t block, | |
1054 | struct dm_buffer **bp) | |
1055 | { | |
1056 | BUG_ON(dm_bufio_in_request()); | |
1057 | ||
1058 | return new_read(c, block, NF_READ, bp); | |
1059 | } | |
1060 | EXPORT_SYMBOL_GPL(dm_bufio_read); | |
1061 | ||
1062 | void *dm_bufio_new(struct dm_bufio_client *c, sector_t block, | |
1063 | struct dm_buffer **bp) | |
1064 | { | |
1065 | BUG_ON(dm_bufio_in_request()); | |
1066 | ||
1067 | return new_read(c, block, NF_FRESH, bp); | |
1068 | } | |
1069 | EXPORT_SYMBOL_GPL(dm_bufio_new); | |
1070 | ||
a66cc28f MP |
1071 | void dm_bufio_prefetch(struct dm_bufio_client *c, |
1072 | sector_t block, unsigned n_blocks) | |
1073 | { | |
1074 | struct blk_plug plug; | |
1075 | ||
2480945c MP |
1076 | LIST_HEAD(write_list); |
1077 | ||
3b6b7813 MP |
1078 | BUG_ON(dm_bufio_in_request()); |
1079 | ||
a66cc28f MP |
1080 | blk_start_plug(&plug); |
1081 | dm_bufio_lock(c); | |
1082 | ||
1083 | for (; n_blocks--; block++) { | |
1084 | int need_submit; | |
1085 | struct dm_buffer *b; | |
2480945c MP |
1086 | b = __bufio_new(c, block, NF_PREFETCH, &need_submit, |
1087 | &write_list); | |
1088 | if (unlikely(!list_empty(&write_list))) { | |
1089 | dm_bufio_unlock(c); | |
1090 | blk_finish_plug(&plug); | |
1091 | __flush_write_list(&write_list); | |
1092 | blk_start_plug(&plug); | |
1093 | dm_bufio_lock(c); | |
1094 | } | |
a66cc28f MP |
1095 | if (unlikely(b != NULL)) { |
1096 | dm_bufio_unlock(c); | |
1097 | ||
1098 | if (need_submit) | |
1099 | submit_io(b, READ, b->block, read_endio); | |
1100 | dm_bufio_release(b); | |
1101 | ||
1102 | dm_bufio_cond_resched(); | |
1103 | ||
1104 | if (!n_blocks) | |
1105 | goto flush_plug; | |
1106 | dm_bufio_lock(c); | |
1107 | } | |
a66cc28f MP |
1108 | } |
1109 | ||
1110 | dm_bufio_unlock(c); | |
1111 | ||
1112 | flush_plug: | |
1113 | blk_finish_plug(&plug); | |
1114 | } | |
1115 | EXPORT_SYMBOL_GPL(dm_bufio_prefetch); | |
1116 | ||
95d402f0 MP |
1117 | void dm_bufio_release(struct dm_buffer *b) |
1118 | { | |
1119 | struct dm_bufio_client *c = b->c; | |
1120 | ||
1121 | dm_bufio_lock(c); | |
1122 | ||
95d402f0 MP |
1123 | BUG_ON(!b->hold_count); |
1124 | ||
1125 | b->hold_count--; | |
1126 | if (!b->hold_count) { | |
1127 | wake_up(&c->free_buffer_wait); | |
1128 | ||
1129 | /* | |
1130 | * If there were errors on the buffer, and the buffer is not | |
1131 | * to be written, free the buffer. There is no point in caching | |
1132 | * invalid buffer. | |
1133 | */ | |
1134 | if ((b->read_error || b->write_error) && | |
a66cc28f | 1135 | !test_bit(B_READING, &b->state) && |
95d402f0 MP |
1136 | !test_bit(B_WRITING, &b->state) && |
1137 | !test_bit(B_DIRTY, &b->state)) { | |
1138 | __unlink_buffer(b); | |
1139 | __free_buffer_wake(b); | |
1140 | } | |
1141 | } | |
1142 | ||
1143 | dm_bufio_unlock(c); | |
1144 | } | |
1145 | EXPORT_SYMBOL_GPL(dm_bufio_release); | |
1146 | ||
1147 | void dm_bufio_mark_buffer_dirty(struct dm_buffer *b) | |
1148 | { | |
1149 | struct dm_bufio_client *c = b->c; | |
1150 | ||
1151 | dm_bufio_lock(c); | |
1152 | ||
a66cc28f MP |
1153 | BUG_ON(test_bit(B_READING, &b->state)); |
1154 | ||
95d402f0 MP |
1155 | if (!test_and_set_bit(B_DIRTY, &b->state)) |
1156 | __relink_lru(b, LIST_DIRTY); | |
1157 | ||
1158 | dm_bufio_unlock(c); | |
1159 | } | |
1160 | EXPORT_SYMBOL_GPL(dm_bufio_mark_buffer_dirty); | |
1161 | ||
1162 | void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c) | |
1163 | { | |
2480945c MP |
1164 | LIST_HEAD(write_list); |
1165 | ||
95d402f0 MP |
1166 | BUG_ON(dm_bufio_in_request()); |
1167 | ||
1168 | dm_bufio_lock(c); | |
2480945c | 1169 | __write_dirty_buffers_async(c, 0, &write_list); |
95d402f0 | 1170 | dm_bufio_unlock(c); |
2480945c | 1171 | __flush_write_list(&write_list); |
95d402f0 MP |
1172 | } |
1173 | EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers_async); | |
1174 | ||
1175 | /* | |
1176 | * For performance, it is essential that the buffers are written asynchronously | |
1177 | * and simultaneously (so that the block layer can merge the writes) and then | |
1178 | * waited upon. | |
1179 | * | |
1180 | * Finally, we flush hardware disk cache. | |
1181 | */ | |
1182 | int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c) | |
1183 | { | |
1184 | int a, f; | |
1185 | unsigned long buffers_processed = 0; | |
1186 | struct dm_buffer *b, *tmp; | |
1187 | ||
2480945c MP |
1188 | LIST_HEAD(write_list); |
1189 | ||
1190 | dm_bufio_lock(c); | |
1191 | __write_dirty_buffers_async(c, 0, &write_list); | |
1192 | dm_bufio_unlock(c); | |
1193 | __flush_write_list(&write_list); | |
95d402f0 | 1194 | dm_bufio_lock(c); |
95d402f0 MP |
1195 | |
1196 | again: | |
1197 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { | |
1198 | int dropped_lock = 0; | |
1199 | ||
1200 | if (buffers_processed < c->n_buffers[LIST_DIRTY]) | |
1201 | buffers_processed++; | |
1202 | ||
1203 | BUG_ON(test_bit(B_READING, &b->state)); | |
1204 | ||
1205 | if (test_bit(B_WRITING, &b->state)) { | |
1206 | if (buffers_processed < c->n_buffers[LIST_DIRTY]) { | |
1207 | dropped_lock = 1; | |
1208 | b->hold_count++; | |
1209 | dm_bufio_unlock(c); | |
1210 | wait_on_bit(&b->state, B_WRITING, | |
1211 | do_io_schedule, | |
1212 | TASK_UNINTERRUPTIBLE); | |
1213 | dm_bufio_lock(c); | |
1214 | b->hold_count--; | |
1215 | } else | |
1216 | wait_on_bit(&b->state, B_WRITING, | |
1217 | do_io_schedule, | |
1218 | TASK_UNINTERRUPTIBLE); | |
1219 | } | |
1220 | ||
1221 | if (!test_bit(B_DIRTY, &b->state) && | |
1222 | !test_bit(B_WRITING, &b->state)) | |
1223 | __relink_lru(b, LIST_CLEAN); | |
1224 | ||
1225 | dm_bufio_cond_resched(); | |
1226 | ||
1227 | /* | |
1228 | * If we dropped the lock, the list is no longer consistent, | |
1229 | * so we must restart the search. | |
1230 | * | |
1231 | * In the most common case, the buffer just processed is | |
1232 | * relinked to the clean list, so we won't loop scanning the | |
1233 | * same buffer again and again. | |
1234 | * | |
1235 | * This may livelock if there is another thread simultaneously | |
1236 | * dirtying buffers, so we count the number of buffers walked | |
1237 | * and if it exceeds the total number of buffers, it means that | |
1238 | * someone is doing some writes simultaneously with us. In | |
1239 | * this case, stop, dropping the lock. | |
1240 | */ | |
1241 | if (dropped_lock) | |
1242 | goto again; | |
1243 | } | |
1244 | wake_up(&c->free_buffer_wait); | |
1245 | dm_bufio_unlock(c); | |
1246 | ||
1247 | a = xchg(&c->async_write_error, 0); | |
1248 | f = dm_bufio_issue_flush(c); | |
1249 | if (a) | |
1250 | return a; | |
1251 | ||
1252 | return f; | |
1253 | } | |
1254 | EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers); | |
1255 | ||
1256 | /* | |
1257 | * Use dm-io to send and empty barrier flush the device. | |
1258 | */ | |
1259 | int dm_bufio_issue_flush(struct dm_bufio_client *c) | |
1260 | { | |
1261 | struct dm_io_request io_req = { | |
3daec3b4 | 1262 | .bi_rw = WRITE_FLUSH, |
95d402f0 MP |
1263 | .mem.type = DM_IO_KMEM, |
1264 | .mem.ptr.addr = NULL, | |
1265 | .client = c->dm_io, | |
1266 | }; | |
1267 | struct dm_io_region io_reg = { | |
1268 | .bdev = c->bdev, | |
1269 | .sector = 0, | |
1270 | .count = 0, | |
1271 | }; | |
1272 | ||
1273 | BUG_ON(dm_bufio_in_request()); | |
1274 | ||
1275 | return dm_io(&io_req, 1, &io_reg, NULL); | |
1276 | } | |
1277 | EXPORT_SYMBOL_GPL(dm_bufio_issue_flush); | |
1278 | ||
1279 | /* | |
1280 | * We first delete any other buffer that may be at that new location. | |
1281 | * | |
1282 | * Then, we write the buffer to the original location if it was dirty. | |
1283 | * | |
1284 | * Then, if we are the only one who is holding the buffer, relink the buffer | |
1285 | * in the hash queue for the new location. | |
1286 | * | |
1287 | * If there was someone else holding the buffer, we write it to the new | |
1288 | * location but not relink it, because that other user needs to have the buffer | |
1289 | * at the same place. | |
1290 | */ | |
1291 | void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block) | |
1292 | { | |
1293 | struct dm_bufio_client *c = b->c; | |
1294 | struct dm_buffer *new; | |
1295 | ||
1296 | BUG_ON(dm_bufio_in_request()); | |
1297 | ||
1298 | dm_bufio_lock(c); | |
1299 | ||
1300 | retry: | |
1301 | new = __find(c, new_block); | |
1302 | if (new) { | |
1303 | if (new->hold_count) { | |
1304 | __wait_for_free_buffer(c); | |
1305 | goto retry; | |
1306 | } | |
1307 | ||
1308 | /* | |
1309 | * FIXME: Is there any point waiting for a write that's going | |
1310 | * to be overwritten in a bit? | |
1311 | */ | |
1312 | __make_buffer_clean(new); | |
1313 | __unlink_buffer(new); | |
1314 | __free_buffer_wake(new); | |
1315 | } | |
1316 | ||
1317 | BUG_ON(!b->hold_count); | |
1318 | BUG_ON(test_bit(B_READING, &b->state)); | |
1319 | ||
2480945c | 1320 | __write_dirty_buffer(b, NULL); |
95d402f0 MP |
1321 | if (b->hold_count == 1) { |
1322 | wait_on_bit(&b->state, B_WRITING, | |
1323 | do_io_schedule, TASK_UNINTERRUPTIBLE); | |
1324 | set_bit(B_DIRTY, &b->state); | |
1325 | __unlink_buffer(b); | |
1326 | __link_buffer(b, new_block, LIST_DIRTY); | |
1327 | } else { | |
1328 | sector_t old_block; | |
1329 | wait_on_bit_lock(&b->state, B_WRITING, | |
1330 | do_io_schedule, TASK_UNINTERRUPTIBLE); | |
1331 | /* | |
1332 | * Relink buffer to "new_block" so that write_callback | |
1333 | * sees "new_block" as a block number. | |
1334 | * After the write, link the buffer back to old_block. | |
1335 | * All this must be done in bufio lock, so that block number | |
1336 | * change isn't visible to other threads. | |
1337 | */ | |
1338 | old_block = b->block; | |
1339 | __unlink_buffer(b); | |
1340 | __link_buffer(b, new_block, b->list_mode); | |
1341 | submit_io(b, WRITE, new_block, write_endio); | |
1342 | wait_on_bit(&b->state, B_WRITING, | |
1343 | do_io_schedule, TASK_UNINTERRUPTIBLE); | |
1344 | __unlink_buffer(b); | |
1345 | __link_buffer(b, old_block, b->list_mode); | |
1346 | } | |
1347 | ||
1348 | dm_bufio_unlock(c); | |
1349 | dm_bufio_release(b); | |
1350 | } | |
1351 | EXPORT_SYMBOL_GPL(dm_bufio_release_move); | |
1352 | ||
1353 | unsigned dm_bufio_get_block_size(struct dm_bufio_client *c) | |
1354 | { | |
1355 | return c->block_size; | |
1356 | } | |
1357 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_size); | |
1358 | ||
1359 | sector_t dm_bufio_get_device_size(struct dm_bufio_client *c) | |
1360 | { | |
1361 | return i_size_read(c->bdev->bd_inode) >> | |
1362 | (SECTOR_SHIFT + c->sectors_per_block_bits); | |
1363 | } | |
1364 | EXPORT_SYMBOL_GPL(dm_bufio_get_device_size); | |
1365 | ||
1366 | sector_t dm_bufio_get_block_number(struct dm_buffer *b) | |
1367 | { | |
1368 | return b->block; | |
1369 | } | |
1370 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_number); | |
1371 | ||
1372 | void *dm_bufio_get_block_data(struct dm_buffer *b) | |
1373 | { | |
1374 | return b->data; | |
1375 | } | |
1376 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_data); | |
1377 | ||
1378 | void *dm_bufio_get_aux_data(struct dm_buffer *b) | |
1379 | { | |
1380 | return b + 1; | |
1381 | } | |
1382 | EXPORT_SYMBOL_GPL(dm_bufio_get_aux_data); | |
1383 | ||
1384 | struct dm_bufio_client *dm_bufio_get_client(struct dm_buffer *b) | |
1385 | { | |
1386 | return b->c; | |
1387 | } | |
1388 | EXPORT_SYMBOL_GPL(dm_bufio_get_client); | |
1389 | ||
1390 | static void drop_buffers(struct dm_bufio_client *c) | |
1391 | { | |
1392 | struct dm_buffer *b; | |
1393 | int i; | |
1394 | ||
1395 | BUG_ON(dm_bufio_in_request()); | |
1396 | ||
1397 | /* | |
1398 | * An optimization so that the buffers are not written one-by-one. | |
1399 | */ | |
1400 | dm_bufio_write_dirty_buffers_async(c); | |
1401 | ||
1402 | dm_bufio_lock(c); | |
1403 | ||
1404 | while ((b = __get_unclaimed_buffer(c))) | |
1405 | __free_buffer_wake(b); | |
1406 | ||
1407 | for (i = 0; i < LIST_SIZE; i++) | |
1408 | list_for_each_entry(b, &c->lru[i], lru_list) | |
1409 | DMERR("leaked buffer %llx, hold count %u, list %d", | |
1410 | (unsigned long long)b->block, b->hold_count, i); | |
1411 | ||
1412 | for (i = 0; i < LIST_SIZE; i++) | |
1413 | BUG_ON(!list_empty(&c->lru[i])); | |
1414 | ||
1415 | dm_bufio_unlock(c); | |
1416 | } | |
1417 | ||
1418 | /* | |
1419 | * Test if the buffer is unused and too old, and commit it. | |
1420 | * At if noio is set, we must not do any I/O because we hold | |
1421 | * dm_bufio_clients_lock and we would risk deadlock if the I/O gets rerouted to | |
1422 | * different bufio client. | |
1423 | */ | |
1424 | static int __cleanup_old_buffer(struct dm_buffer *b, gfp_t gfp, | |
1425 | unsigned long max_jiffies) | |
1426 | { | |
1427 | if (jiffies - b->last_accessed < max_jiffies) | |
7dc19d5a | 1428 | return 0; |
95d402f0 MP |
1429 | |
1430 | if (!(gfp & __GFP_IO)) { | |
1431 | if (test_bit(B_READING, &b->state) || | |
1432 | test_bit(B_WRITING, &b->state) || | |
1433 | test_bit(B_DIRTY, &b->state)) | |
7dc19d5a | 1434 | return 0; |
95d402f0 MP |
1435 | } |
1436 | ||
1437 | if (b->hold_count) | |
7dc19d5a | 1438 | return 0; |
95d402f0 MP |
1439 | |
1440 | __make_buffer_clean(b); | |
1441 | __unlink_buffer(b); | |
1442 | __free_buffer_wake(b); | |
1443 | ||
7dc19d5a | 1444 | return 1; |
95d402f0 MP |
1445 | } |
1446 | ||
7dc19d5a DC |
1447 | static long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan, |
1448 | gfp_t gfp_mask) | |
95d402f0 MP |
1449 | { |
1450 | int l; | |
1451 | struct dm_buffer *b, *tmp; | |
7dc19d5a | 1452 | long freed = 0; |
95d402f0 MP |
1453 | |
1454 | for (l = 0; l < LIST_SIZE; l++) { | |
7dc19d5a DC |
1455 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list) { |
1456 | freed += __cleanup_old_buffer(b, gfp_mask, 0); | |
1457 | if (!--nr_to_scan) | |
1458 | break; | |
1459 | } | |
95d402f0 MP |
1460 | dm_bufio_cond_resched(); |
1461 | } | |
7dc19d5a | 1462 | return freed; |
95d402f0 MP |
1463 | } |
1464 | ||
7dc19d5a DC |
1465 | static unsigned long |
1466 | dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) | |
95d402f0 | 1467 | { |
7dc19d5a DC |
1468 | struct dm_bufio_client *c; |
1469 | unsigned long freed; | |
95d402f0 | 1470 | |
7dc19d5a | 1471 | c = container_of(shrink, struct dm_bufio_client, shrinker); |
95d402f0 MP |
1472 | if (sc->gfp_mask & __GFP_IO) |
1473 | dm_bufio_lock(c); | |
1474 | else if (!dm_bufio_trylock(c)) | |
7dc19d5a | 1475 | return SHRINK_STOP; |
95d402f0 | 1476 | |
7dc19d5a DC |
1477 | freed = __scan(c, sc->nr_to_scan, sc->gfp_mask); |
1478 | dm_bufio_unlock(c); | |
1479 | return freed; | |
1480 | } | |
95d402f0 | 1481 | |
7dc19d5a DC |
1482 | static unsigned long |
1483 | dm_bufio_shrink_count(struct shrinker *shrink, struct shrink_control *sc) | |
1484 | { | |
1485 | struct dm_bufio_client *c; | |
1486 | unsigned long count; | |
95d402f0 | 1487 | |
7dc19d5a DC |
1488 | c = container_of(shrink, struct dm_bufio_client, shrinker); |
1489 | if (sc->gfp_mask & __GFP_IO) | |
1490 | dm_bufio_lock(c); | |
1491 | else if (!dm_bufio_trylock(c)) | |
1492 | return 0; | |
95d402f0 | 1493 | |
7dc19d5a DC |
1494 | count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY]; |
1495 | dm_bufio_unlock(c); | |
1496 | return count; | |
95d402f0 MP |
1497 | } |
1498 | ||
1499 | /* | |
1500 | * Create the buffering interface | |
1501 | */ | |
1502 | struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsigned block_size, | |
1503 | unsigned reserved_buffers, unsigned aux_size, | |
1504 | void (*alloc_callback)(struct dm_buffer *), | |
1505 | void (*write_callback)(struct dm_buffer *)) | |
1506 | { | |
1507 | int r; | |
1508 | struct dm_bufio_client *c; | |
1509 | unsigned i; | |
1510 | ||
1511 | BUG_ON(block_size < 1 << SECTOR_SHIFT || | |
1512 | (block_size & (block_size - 1))); | |
1513 | ||
1514 | c = kmalloc(sizeof(*c), GFP_KERNEL); | |
1515 | if (!c) { | |
1516 | r = -ENOMEM; | |
1517 | goto bad_client; | |
1518 | } | |
1519 | c->cache_hash = vmalloc(sizeof(struct hlist_head) << DM_BUFIO_HASH_BITS); | |
1520 | if (!c->cache_hash) { | |
1521 | r = -ENOMEM; | |
1522 | goto bad_hash; | |
1523 | } | |
1524 | ||
1525 | c->bdev = bdev; | |
1526 | c->block_size = block_size; | |
1527 | c->sectors_per_block_bits = ffs(block_size) - 1 - SECTOR_SHIFT; | |
1528 | c->pages_per_block_bits = (ffs(block_size) - 1 >= PAGE_SHIFT) ? | |
1529 | ffs(block_size) - 1 - PAGE_SHIFT : 0; | |
1530 | c->blocks_per_page_bits = (ffs(block_size) - 1 < PAGE_SHIFT ? | |
1531 | PAGE_SHIFT - (ffs(block_size) - 1) : 0); | |
1532 | ||
1533 | c->aux_size = aux_size; | |
1534 | c->alloc_callback = alloc_callback; | |
1535 | c->write_callback = write_callback; | |
1536 | ||
1537 | for (i = 0; i < LIST_SIZE; i++) { | |
1538 | INIT_LIST_HEAD(&c->lru[i]); | |
1539 | c->n_buffers[i] = 0; | |
1540 | } | |
1541 | ||
1542 | for (i = 0; i < 1 << DM_BUFIO_HASH_BITS; i++) | |
1543 | INIT_HLIST_HEAD(&c->cache_hash[i]); | |
1544 | ||
1545 | mutex_init(&c->lock); | |
1546 | INIT_LIST_HEAD(&c->reserved_buffers); | |
1547 | c->need_reserved_buffers = reserved_buffers; | |
1548 | ||
1549 | init_waitqueue_head(&c->free_buffer_wait); | |
1550 | c->async_write_error = 0; | |
1551 | ||
1552 | c->dm_io = dm_io_client_create(); | |
1553 | if (IS_ERR(c->dm_io)) { | |
1554 | r = PTR_ERR(c->dm_io); | |
1555 | goto bad_dm_io; | |
1556 | } | |
1557 | ||
1558 | mutex_lock(&dm_bufio_clients_lock); | |
1559 | if (c->blocks_per_page_bits) { | |
1560 | if (!DM_BUFIO_CACHE_NAME(c)) { | |
1561 | DM_BUFIO_CACHE_NAME(c) = kasprintf(GFP_KERNEL, "dm_bufio_cache-%u", c->block_size); | |
1562 | if (!DM_BUFIO_CACHE_NAME(c)) { | |
1563 | r = -ENOMEM; | |
1564 | mutex_unlock(&dm_bufio_clients_lock); | |
1565 | goto bad_cache; | |
1566 | } | |
1567 | } | |
1568 | ||
1569 | if (!DM_BUFIO_CACHE(c)) { | |
1570 | DM_BUFIO_CACHE(c) = kmem_cache_create(DM_BUFIO_CACHE_NAME(c), | |
1571 | c->block_size, | |
1572 | c->block_size, 0, NULL); | |
1573 | if (!DM_BUFIO_CACHE(c)) { | |
1574 | r = -ENOMEM; | |
1575 | mutex_unlock(&dm_bufio_clients_lock); | |
1576 | goto bad_cache; | |
1577 | } | |
1578 | } | |
1579 | } | |
1580 | mutex_unlock(&dm_bufio_clients_lock); | |
1581 | ||
1582 | while (c->need_reserved_buffers) { | |
1583 | struct dm_buffer *b = alloc_buffer(c, GFP_KERNEL); | |
1584 | ||
1585 | if (!b) { | |
1586 | r = -ENOMEM; | |
1587 | goto bad_buffer; | |
1588 | } | |
1589 | __free_buffer_wake(b); | |
1590 | } | |
1591 | ||
1592 | mutex_lock(&dm_bufio_clients_lock); | |
1593 | dm_bufio_client_count++; | |
1594 | list_add(&c->client_list, &dm_bufio_all_clients); | |
1595 | __cache_size_refresh(); | |
1596 | mutex_unlock(&dm_bufio_clients_lock); | |
1597 | ||
7dc19d5a DC |
1598 | c->shrinker.count_objects = dm_bufio_shrink_count; |
1599 | c->shrinker.scan_objects = dm_bufio_shrink_scan; | |
95d402f0 MP |
1600 | c->shrinker.seeks = 1; |
1601 | c->shrinker.batch = 0; | |
1602 | register_shrinker(&c->shrinker); | |
1603 | ||
1604 | return c; | |
1605 | ||
1606 | bad_buffer: | |
1607 | bad_cache: | |
1608 | while (!list_empty(&c->reserved_buffers)) { | |
1609 | struct dm_buffer *b = list_entry(c->reserved_buffers.next, | |
1610 | struct dm_buffer, lru_list); | |
1611 | list_del(&b->lru_list); | |
1612 | free_buffer(b); | |
1613 | } | |
1614 | dm_io_client_destroy(c->dm_io); | |
1615 | bad_dm_io: | |
1616 | vfree(c->cache_hash); | |
1617 | bad_hash: | |
1618 | kfree(c); | |
1619 | bad_client: | |
1620 | return ERR_PTR(r); | |
1621 | } | |
1622 | EXPORT_SYMBOL_GPL(dm_bufio_client_create); | |
1623 | ||
1624 | /* | |
1625 | * Free the buffering interface. | |
1626 | * It is required that there are no references on any buffers. | |
1627 | */ | |
1628 | void dm_bufio_client_destroy(struct dm_bufio_client *c) | |
1629 | { | |
1630 | unsigned i; | |
1631 | ||
1632 | drop_buffers(c); | |
1633 | ||
1634 | unregister_shrinker(&c->shrinker); | |
1635 | ||
1636 | mutex_lock(&dm_bufio_clients_lock); | |
1637 | ||
1638 | list_del(&c->client_list); | |
1639 | dm_bufio_client_count--; | |
1640 | __cache_size_refresh(); | |
1641 | ||
1642 | mutex_unlock(&dm_bufio_clients_lock); | |
1643 | ||
1644 | for (i = 0; i < 1 << DM_BUFIO_HASH_BITS; i++) | |
1645 | BUG_ON(!hlist_empty(&c->cache_hash[i])); | |
1646 | ||
1647 | BUG_ON(c->need_reserved_buffers); | |
1648 | ||
1649 | while (!list_empty(&c->reserved_buffers)) { | |
1650 | struct dm_buffer *b = list_entry(c->reserved_buffers.next, | |
1651 | struct dm_buffer, lru_list); | |
1652 | list_del(&b->lru_list); | |
1653 | free_buffer(b); | |
1654 | } | |
1655 | ||
1656 | for (i = 0; i < LIST_SIZE; i++) | |
1657 | if (c->n_buffers[i]) | |
1658 | DMERR("leaked buffer count %d: %ld", i, c->n_buffers[i]); | |
1659 | ||
1660 | for (i = 0; i < LIST_SIZE; i++) | |
1661 | BUG_ON(c->n_buffers[i]); | |
1662 | ||
1663 | dm_io_client_destroy(c->dm_io); | |
1664 | vfree(c->cache_hash); | |
1665 | kfree(c); | |
1666 | } | |
1667 | EXPORT_SYMBOL_GPL(dm_bufio_client_destroy); | |
1668 | ||
1669 | static void cleanup_old_buffers(void) | |
1670 | { | |
fe5fe906 | 1671 | unsigned long max_age = ACCESS_ONCE(dm_bufio_max_age); |
95d402f0 MP |
1672 | struct dm_bufio_client *c; |
1673 | ||
95d402f0 MP |
1674 | if (max_age > ULONG_MAX / HZ) |
1675 | max_age = ULONG_MAX / HZ; | |
1676 | ||
1677 | mutex_lock(&dm_bufio_clients_lock); | |
1678 | list_for_each_entry(c, &dm_bufio_all_clients, client_list) { | |
1679 | if (!dm_bufio_trylock(c)) | |
1680 | continue; | |
1681 | ||
1682 | while (!list_empty(&c->lru[LIST_CLEAN])) { | |
1683 | struct dm_buffer *b; | |
1684 | b = list_entry(c->lru[LIST_CLEAN].prev, | |
1685 | struct dm_buffer, lru_list); | |
7dc19d5a | 1686 | if (!__cleanup_old_buffer(b, 0, max_age * HZ)) |
95d402f0 MP |
1687 | break; |
1688 | dm_bufio_cond_resched(); | |
1689 | } | |
1690 | ||
1691 | dm_bufio_unlock(c); | |
1692 | dm_bufio_cond_resched(); | |
1693 | } | |
1694 | mutex_unlock(&dm_bufio_clients_lock); | |
1695 | } | |
1696 | ||
1697 | static struct workqueue_struct *dm_bufio_wq; | |
1698 | static struct delayed_work dm_bufio_work; | |
1699 | ||
1700 | static void work_fn(struct work_struct *w) | |
1701 | { | |
1702 | cleanup_old_buffers(); | |
1703 | ||
1704 | queue_delayed_work(dm_bufio_wq, &dm_bufio_work, | |
1705 | DM_BUFIO_WORK_TIMER_SECS * HZ); | |
1706 | } | |
1707 | ||
1708 | /*---------------------------------------------------------------- | |
1709 | * Module setup | |
1710 | *--------------------------------------------------------------*/ | |
1711 | ||
1712 | /* | |
1713 | * This is called only once for the whole dm_bufio module. | |
1714 | * It initializes memory limit. | |
1715 | */ | |
1716 | static int __init dm_bufio_init(void) | |
1717 | { | |
1718 | __u64 mem; | |
1719 | ||
4cb57ab4 MP |
1720 | dm_bufio_allocated_kmem_cache = 0; |
1721 | dm_bufio_allocated_get_free_pages = 0; | |
1722 | dm_bufio_allocated_vmalloc = 0; | |
1723 | dm_bufio_current_allocated = 0; | |
1724 | ||
95d402f0 MP |
1725 | memset(&dm_bufio_caches, 0, sizeof dm_bufio_caches); |
1726 | memset(&dm_bufio_cache_names, 0, sizeof dm_bufio_cache_names); | |
1727 | ||
1728 | mem = (__u64)((totalram_pages - totalhigh_pages) * | |
1729 | DM_BUFIO_MEMORY_PERCENT / 100) << PAGE_SHIFT; | |
1730 | ||
1731 | if (mem > ULONG_MAX) | |
1732 | mem = ULONG_MAX; | |
1733 | ||
1734 | #ifdef CONFIG_MMU | |
1735 | /* | |
1736 | * Get the size of vmalloc space the same way as VMALLOC_TOTAL | |
1737 | * in fs/proc/internal.h | |
1738 | */ | |
1739 | if (mem > (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100) | |
1740 | mem = (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100; | |
1741 | #endif | |
1742 | ||
1743 | dm_bufio_default_cache_size = mem; | |
1744 | ||
1745 | mutex_lock(&dm_bufio_clients_lock); | |
1746 | __cache_size_refresh(); | |
1747 | mutex_unlock(&dm_bufio_clients_lock); | |
1748 | ||
1749 | dm_bufio_wq = create_singlethread_workqueue("dm_bufio_cache"); | |
1750 | if (!dm_bufio_wq) | |
1751 | return -ENOMEM; | |
1752 | ||
1753 | INIT_DELAYED_WORK(&dm_bufio_work, work_fn); | |
1754 | queue_delayed_work(dm_bufio_wq, &dm_bufio_work, | |
1755 | DM_BUFIO_WORK_TIMER_SECS * HZ); | |
1756 | ||
1757 | return 0; | |
1758 | } | |
1759 | ||
1760 | /* | |
1761 | * This is called once when unloading the dm_bufio module. | |
1762 | */ | |
1763 | static void __exit dm_bufio_exit(void) | |
1764 | { | |
1765 | int bug = 0; | |
1766 | int i; | |
1767 | ||
1768 | cancel_delayed_work_sync(&dm_bufio_work); | |
1769 | destroy_workqueue(dm_bufio_wq); | |
1770 | ||
1771 | for (i = 0; i < ARRAY_SIZE(dm_bufio_caches); i++) { | |
1772 | struct kmem_cache *kc = dm_bufio_caches[i]; | |
1773 | ||
1774 | if (kc) | |
1775 | kmem_cache_destroy(kc); | |
1776 | } | |
1777 | ||
1778 | for (i = 0; i < ARRAY_SIZE(dm_bufio_cache_names); i++) | |
1779 | kfree(dm_bufio_cache_names[i]); | |
1780 | ||
1781 | if (dm_bufio_client_count) { | |
1782 | DMCRIT("%s: dm_bufio_client_count leaked: %d", | |
1783 | __func__, dm_bufio_client_count); | |
1784 | bug = 1; | |
1785 | } | |
1786 | ||
1787 | if (dm_bufio_current_allocated) { | |
1788 | DMCRIT("%s: dm_bufio_current_allocated leaked: %lu", | |
1789 | __func__, dm_bufio_current_allocated); | |
1790 | bug = 1; | |
1791 | } | |
1792 | ||
1793 | if (dm_bufio_allocated_get_free_pages) { | |
1794 | DMCRIT("%s: dm_bufio_allocated_get_free_pages leaked: %lu", | |
1795 | __func__, dm_bufio_allocated_get_free_pages); | |
1796 | bug = 1; | |
1797 | } | |
1798 | ||
1799 | if (dm_bufio_allocated_vmalloc) { | |
1800 | DMCRIT("%s: dm_bufio_vmalloc leaked: %lu", | |
1801 | __func__, dm_bufio_allocated_vmalloc); | |
1802 | bug = 1; | |
1803 | } | |
1804 | ||
1805 | if (bug) | |
1806 | BUG(); | |
1807 | } | |
1808 | ||
1809 | module_init(dm_bufio_init) | |
1810 | module_exit(dm_bufio_exit) | |
1811 | ||
1812 | module_param_named(max_cache_size_bytes, dm_bufio_cache_size, ulong, S_IRUGO | S_IWUSR); | |
1813 | MODULE_PARM_DESC(max_cache_size_bytes, "Size of metadata cache"); | |
1814 | ||
1815 | module_param_named(max_age_seconds, dm_bufio_max_age, uint, S_IRUGO | S_IWUSR); | |
1816 | MODULE_PARM_DESC(max_age_seconds, "Max age of a buffer in seconds"); | |
1817 | ||
1818 | module_param_named(peak_allocated_bytes, dm_bufio_peak_allocated, ulong, S_IRUGO | S_IWUSR); | |
1819 | MODULE_PARM_DESC(peak_allocated_bytes, "Tracks the maximum allocated memory"); | |
1820 | ||
1821 | module_param_named(allocated_kmem_cache_bytes, dm_bufio_allocated_kmem_cache, ulong, S_IRUGO); | |
1822 | MODULE_PARM_DESC(allocated_kmem_cache_bytes, "Memory allocated with kmem_cache_alloc"); | |
1823 | ||
1824 | module_param_named(allocated_get_free_pages_bytes, dm_bufio_allocated_get_free_pages, ulong, S_IRUGO); | |
1825 | MODULE_PARM_DESC(allocated_get_free_pages_bytes, "Memory allocated with get_free_pages"); | |
1826 | ||
1827 | module_param_named(allocated_vmalloc_bytes, dm_bufio_allocated_vmalloc, ulong, S_IRUGO); | |
1828 | MODULE_PARM_DESC(allocated_vmalloc_bytes, "Memory allocated with vmalloc"); | |
1829 | ||
1830 | module_param_named(current_allocated_bytes, dm_bufio_current_allocated, ulong, S_IRUGO); | |
1831 | MODULE_PARM_DESC(current_allocated_bytes, "Memory currently used by the cache"); | |
1832 | ||
1833 | MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>"); | |
1834 | MODULE_DESCRIPTION(DM_NAME " buffered I/O library"); | |
1835 | MODULE_LICENSE("GPL"); |