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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 | ||
55b082e6 MP |
107 | unsigned minimum_buffers; |
108 | ||
95d402f0 MP |
109 | struct hlist_head *cache_hash; |
110 | wait_queue_head_t free_buffer_wait; | |
111 | ||
112 | int async_write_error; | |
113 | ||
114 | struct list_head client_list; | |
115 | struct shrinker shrinker; | |
116 | }; | |
117 | ||
118 | /* | |
119 | * Buffer state bits. | |
120 | */ | |
121 | #define B_READING 0 | |
122 | #define B_WRITING 1 | |
123 | #define B_DIRTY 2 | |
124 | ||
125 | /* | |
126 | * Describes how the block was allocated: | |
127 | * kmem_cache_alloc(), __get_free_pages() or vmalloc(). | |
128 | * See the comment at alloc_buffer_data. | |
129 | */ | |
130 | enum data_mode { | |
131 | DATA_MODE_SLAB = 0, | |
132 | DATA_MODE_GET_FREE_PAGES = 1, | |
133 | DATA_MODE_VMALLOC = 2, | |
134 | DATA_MODE_LIMIT = 3 | |
135 | }; | |
136 | ||
137 | struct dm_buffer { | |
138 | struct hlist_node hash_list; | |
139 | struct list_head lru_list; | |
140 | sector_t block; | |
141 | void *data; | |
142 | enum data_mode data_mode; | |
143 | unsigned char list_mode; /* LIST_* */ | |
144 | unsigned hold_count; | |
145 | int read_error; | |
146 | int write_error; | |
147 | unsigned long state; | |
148 | unsigned long last_accessed; | |
149 | struct dm_bufio_client *c; | |
2480945c | 150 | struct list_head write_list; |
95d402f0 MP |
151 | struct bio bio; |
152 | struct bio_vec bio_vec[DM_BUFIO_INLINE_VECS]; | |
153 | }; | |
154 | ||
155 | /*----------------------------------------------------------------*/ | |
156 | ||
157 | static struct kmem_cache *dm_bufio_caches[PAGE_SHIFT - SECTOR_SHIFT]; | |
158 | static char *dm_bufio_cache_names[PAGE_SHIFT - SECTOR_SHIFT]; | |
159 | ||
160 | static inline int dm_bufio_cache_index(struct dm_bufio_client *c) | |
161 | { | |
162 | unsigned ret = c->blocks_per_page_bits - 1; | |
163 | ||
164 | BUG_ON(ret >= ARRAY_SIZE(dm_bufio_caches)); | |
165 | ||
166 | return ret; | |
167 | } | |
168 | ||
169 | #define DM_BUFIO_CACHE(c) (dm_bufio_caches[dm_bufio_cache_index(c)]) | |
170 | #define DM_BUFIO_CACHE_NAME(c) (dm_bufio_cache_names[dm_bufio_cache_index(c)]) | |
171 | ||
172 | #define dm_bufio_in_request() (!!current->bio_list) | |
173 | ||
174 | static void dm_bufio_lock(struct dm_bufio_client *c) | |
175 | { | |
176 | mutex_lock_nested(&c->lock, dm_bufio_in_request()); | |
177 | } | |
178 | ||
179 | static int dm_bufio_trylock(struct dm_bufio_client *c) | |
180 | { | |
181 | return mutex_trylock(&c->lock); | |
182 | } | |
183 | ||
184 | static void dm_bufio_unlock(struct dm_bufio_client *c) | |
185 | { | |
186 | mutex_unlock(&c->lock); | |
187 | } | |
188 | ||
189 | /* | |
190 | * FIXME Move to sched.h? | |
191 | */ | |
192 | #ifdef CONFIG_PREEMPT_VOLUNTARY | |
193 | # define dm_bufio_cond_resched() \ | |
194 | do { \ | |
195 | if (unlikely(need_resched())) \ | |
196 | _cond_resched(); \ | |
197 | } while (0) | |
198 | #else | |
199 | # define dm_bufio_cond_resched() do { } while (0) | |
200 | #endif | |
201 | ||
202 | /*----------------------------------------------------------------*/ | |
203 | ||
204 | /* | |
205 | * Default cache size: available memory divided by the ratio. | |
206 | */ | |
207 | static unsigned long dm_bufio_default_cache_size; | |
208 | ||
209 | /* | |
210 | * Total cache size set by the user. | |
211 | */ | |
212 | static unsigned long dm_bufio_cache_size; | |
213 | ||
214 | /* | |
215 | * A copy of dm_bufio_cache_size because dm_bufio_cache_size can change | |
216 | * at any time. If it disagrees, the user has changed cache size. | |
217 | */ | |
218 | static unsigned long dm_bufio_cache_size_latch; | |
219 | ||
220 | static DEFINE_SPINLOCK(param_spinlock); | |
221 | ||
222 | /* | |
223 | * Buffers are freed after this timeout | |
224 | */ | |
225 | static unsigned dm_bufio_max_age = DM_BUFIO_DEFAULT_AGE_SECS; | |
226 | ||
227 | static unsigned long dm_bufio_peak_allocated; | |
228 | static unsigned long dm_bufio_allocated_kmem_cache; | |
229 | static unsigned long dm_bufio_allocated_get_free_pages; | |
230 | static unsigned long dm_bufio_allocated_vmalloc; | |
231 | static unsigned long dm_bufio_current_allocated; | |
232 | ||
233 | /*----------------------------------------------------------------*/ | |
234 | ||
235 | /* | |
236 | * Per-client cache: dm_bufio_cache_size / dm_bufio_client_count | |
237 | */ | |
238 | static unsigned long dm_bufio_cache_size_per_client; | |
239 | ||
240 | /* | |
241 | * The current number of clients. | |
242 | */ | |
243 | static int dm_bufio_client_count; | |
244 | ||
245 | /* | |
246 | * The list of all clients. | |
247 | */ | |
248 | static LIST_HEAD(dm_bufio_all_clients); | |
249 | ||
250 | /* | |
251 | * This mutex protects dm_bufio_cache_size_latch, | |
252 | * dm_bufio_cache_size_per_client and dm_bufio_client_count | |
253 | */ | |
254 | static DEFINE_MUTEX(dm_bufio_clients_lock); | |
255 | ||
256 | /*----------------------------------------------------------------*/ | |
257 | ||
258 | static void adjust_total_allocated(enum data_mode data_mode, long diff) | |
259 | { | |
260 | static unsigned long * const class_ptr[DATA_MODE_LIMIT] = { | |
261 | &dm_bufio_allocated_kmem_cache, | |
262 | &dm_bufio_allocated_get_free_pages, | |
263 | &dm_bufio_allocated_vmalloc, | |
264 | }; | |
265 | ||
266 | spin_lock(¶m_spinlock); | |
267 | ||
268 | *class_ptr[data_mode] += diff; | |
269 | ||
270 | dm_bufio_current_allocated += diff; | |
271 | ||
272 | if (dm_bufio_current_allocated > dm_bufio_peak_allocated) | |
273 | dm_bufio_peak_allocated = dm_bufio_current_allocated; | |
274 | ||
275 | spin_unlock(¶m_spinlock); | |
276 | } | |
277 | ||
278 | /* | |
279 | * Change the number of clients and recalculate per-client limit. | |
280 | */ | |
281 | static void __cache_size_refresh(void) | |
282 | { | |
283 | BUG_ON(!mutex_is_locked(&dm_bufio_clients_lock)); | |
284 | BUG_ON(dm_bufio_client_count < 0); | |
285 | ||
fe5fe906 | 286 | dm_bufio_cache_size_latch = ACCESS_ONCE(dm_bufio_cache_size); |
95d402f0 MP |
287 | |
288 | /* | |
289 | * Use default if set to 0 and report the actual cache size used. | |
290 | */ | |
291 | if (!dm_bufio_cache_size_latch) { | |
292 | (void)cmpxchg(&dm_bufio_cache_size, 0, | |
293 | dm_bufio_default_cache_size); | |
294 | dm_bufio_cache_size_latch = dm_bufio_default_cache_size; | |
295 | } | |
296 | ||
297 | dm_bufio_cache_size_per_client = dm_bufio_cache_size_latch / | |
298 | (dm_bufio_client_count ? : 1); | |
299 | } | |
300 | ||
301 | /* | |
302 | * Allocating buffer data. | |
303 | * | |
304 | * Small buffers are allocated with kmem_cache, to use space optimally. | |
305 | * | |
306 | * For large buffers, we choose between get_free_pages and vmalloc. | |
307 | * Each has advantages and disadvantages. | |
308 | * | |
309 | * __get_free_pages can randomly fail if the memory is fragmented. | |
310 | * __vmalloc won't randomly fail, but vmalloc space is limited (it may be | |
311 | * as low as 128M) so using it for caching is not appropriate. | |
312 | * | |
313 | * If the allocation may fail we use __get_free_pages. Memory fragmentation | |
314 | * won't have a fatal effect here, but it just causes flushes of some other | |
315 | * buffers and more I/O will be performed. Don't use __get_free_pages if it | |
316 | * always fails (i.e. order >= MAX_ORDER). | |
317 | * | |
318 | * If the allocation shouldn't fail we use __vmalloc. This is only for the | |
319 | * initial reserve allocation, so there's no risk of wasting all vmalloc | |
320 | * space. | |
321 | */ | |
322 | static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask, | |
323 | enum data_mode *data_mode) | |
324 | { | |
502624bd MP |
325 | unsigned noio_flag; |
326 | void *ptr; | |
327 | ||
95d402f0 MP |
328 | if (c->block_size <= DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT) { |
329 | *data_mode = DATA_MODE_SLAB; | |
330 | return kmem_cache_alloc(DM_BUFIO_CACHE(c), gfp_mask); | |
331 | } | |
332 | ||
333 | if (c->block_size <= DM_BUFIO_BLOCK_SIZE_GFP_LIMIT && | |
334 | gfp_mask & __GFP_NORETRY) { | |
335 | *data_mode = DATA_MODE_GET_FREE_PAGES; | |
336 | return (void *)__get_free_pages(gfp_mask, | |
337 | c->pages_per_block_bits); | |
338 | } | |
339 | ||
340 | *data_mode = DATA_MODE_VMALLOC; | |
502624bd MP |
341 | |
342 | /* | |
343 | * __vmalloc allocates the data pages and auxiliary structures with | |
344 | * gfp_flags that were specified, but pagetables are always allocated | |
345 | * with GFP_KERNEL, no matter what was specified as gfp_mask. | |
346 | * | |
347 | * Consequently, we must set per-process flag PF_MEMALLOC_NOIO so that | |
348 | * all allocations done by this process (including pagetables) are done | |
349 | * as if GFP_NOIO was specified. | |
350 | */ | |
351 | ||
352 | if (gfp_mask & __GFP_NORETRY) | |
353 | noio_flag = memalloc_noio_save(); | |
354 | ||
220cd058 | 355 | ptr = __vmalloc(c->block_size, gfp_mask | __GFP_HIGHMEM, PAGE_KERNEL); |
502624bd MP |
356 | |
357 | if (gfp_mask & __GFP_NORETRY) | |
358 | memalloc_noio_restore(noio_flag); | |
359 | ||
360 | return ptr; | |
95d402f0 MP |
361 | } |
362 | ||
363 | /* | |
364 | * Free buffer's data. | |
365 | */ | |
366 | static void free_buffer_data(struct dm_bufio_client *c, | |
367 | void *data, enum data_mode data_mode) | |
368 | { | |
369 | switch (data_mode) { | |
370 | case DATA_MODE_SLAB: | |
371 | kmem_cache_free(DM_BUFIO_CACHE(c), data); | |
372 | break; | |
373 | ||
374 | case DATA_MODE_GET_FREE_PAGES: | |
375 | free_pages((unsigned long)data, c->pages_per_block_bits); | |
376 | break; | |
377 | ||
378 | case DATA_MODE_VMALLOC: | |
379 | vfree(data); | |
380 | break; | |
381 | ||
382 | default: | |
383 | DMCRIT("dm_bufio_free_buffer_data: bad data mode: %d", | |
384 | data_mode); | |
385 | BUG(); | |
386 | } | |
387 | } | |
388 | ||
389 | /* | |
390 | * Allocate buffer and its data. | |
391 | */ | |
392 | static struct dm_buffer *alloc_buffer(struct dm_bufio_client *c, gfp_t gfp_mask) | |
393 | { | |
394 | struct dm_buffer *b = kmalloc(sizeof(struct dm_buffer) + c->aux_size, | |
395 | gfp_mask); | |
396 | ||
397 | if (!b) | |
398 | return NULL; | |
399 | ||
400 | b->c = c; | |
401 | ||
402 | b->data = alloc_buffer_data(c, gfp_mask, &b->data_mode); | |
403 | if (!b->data) { | |
404 | kfree(b); | |
405 | return NULL; | |
406 | } | |
407 | ||
408 | adjust_total_allocated(b->data_mode, (long)c->block_size); | |
409 | ||
410 | return b; | |
411 | } | |
412 | ||
413 | /* | |
414 | * Free buffer and its data. | |
415 | */ | |
416 | static void free_buffer(struct dm_buffer *b) | |
417 | { | |
418 | struct dm_bufio_client *c = b->c; | |
419 | ||
420 | adjust_total_allocated(b->data_mode, -(long)c->block_size); | |
421 | ||
422 | free_buffer_data(c, b->data, b->data_mode); | |
423 | kfree(b); | |
424 | } | |
425 | ||
426 | /* | |
427 | * Link buffer to the hash list and clean or dirty queue. | |
428 | */ | |
429 | static void __link_buffer(struct dm_buffer *b, sector_t block, int dirty) | |
430 | { | |
431 | struct dm_bufio_client *c = b->c; | |
432 | ||
433 | c->n_buffers[dirty]++; | |
434 | b->block = block; | |
435 | b->list_mode = dirty; | |
436 | list_add(&b->lru_list, &c->lru[dirty]); | |
437 | hlist_add_head(&b->hash_list, &c->cache_hash[DM_BUFIO_HASH(block)]); | |
438 | b->last_accessed = jiffies; | |
439 | } | |
440 | ||
441 | /* | |
442 | * Unlink buffer from the hash list and dirty or clean queue. | |
443 | */ | |
444 | static void __unlink_buffer(struct dm_buffer *b) | |
445 | { | |
446 | struct dm_bufio_client *c = b->c; | |
447 | ||
448 | BUG_ON(!c->n_buffers[b->list_mode]); | |
449 | ||
450 | c->n_buffers[b->list_mode]--; | |
451 | hlist_del(&b->hash_list); | |
452 | list_del(&b->lru_list); | |
453 | } | |
454 | ||
455 | /* | |
456 | * Place the buffer to the head of dirty or clean LRU queue. | |
457 | */ | |
458 | static void __relink_lru(struct dm_buffer *b, int dirty) | |
459 | { | |
460 | struct dm_bufio_client *c = b->c; | |
461 | ||
462 | BUG_ON(!c->n_buffers[b->list_mode]); | |
463 | ||
464 | c->n_buffers[b->list_mode]--; | |
465 | c->n_buffers[dirty]++; | |
466 | b->list_mode = dirty; | |
54499afb | 467 | list_move(&b->lru_list, &c->lru[dirty]); |
eb76faf5 | 468 | b->last_accessed = jiffies; |
95d402f0 MP |
469 | } |
470 | ||
471 | /*---------------------------------------------------------------- | |
472 | * Submit I/O on the buffer. | |
473 | * | |
474 | * Bio interface is faster but it has some problems: | |
475 | * the vector list is limited (increasing this limit increases | |
476 | * memory-consumption per buffer, so it is not viable); | |
477 | * | |
478 | * the memory must be direct-mapped, not vmalloced; | |
479 | * | |
480 | * the I/O driver can reject requests spuriously if it thinks that | |
481 | * the requests are too big for the device or if they cross a | |
482 | * controller-defined memory boundary. | |
483 | * | |
484 | * If the buffer is small enough (up to DM_BUFIO_INLINE_VECS pages) and | |
485 | * it is not vmalloced, try using the bio interface. | |
486 | * | |
487 | * If the buffer is big, if it is vmalloced or if the underlying device | |
488 | * rejects the bio because it is too large, use dm-io layer to do the I/O. | |
489 | * The dm-io layer splits the I/O into multiple requests, avoiding the above | |
490 | * shortcomings. | |
491 | *--------------------------------------------------------------*/ | |
492 | ||
493 | /* | |
494 | * dm-io completion routine. It just calls b->bio.bi_end_io, pretending | |
495 | * that the request was handled directly with bio interface. | |
496 | */ | |
497 | static void dmio_complete(unsigned long error, void *context) | |
498 | { | |
499 | struct dm_buffer *b = context; | |
500 | ||
501 | b->bio.bi_end_io(&b->bio, error ? -EIO : 0); | |
502 | } | |
503 | ||
504 | static void use_dmio(struct dm_buffer *b, int rw, sector_t block, | |
505 | bio_end_io_t *end_io) | |
506 | { | |
507 | int r; | |
508 | struct dm_io_request io_req = { | |
509 | .bi_rw = rw, | |
510 | .notify.fn = dmio_complete, | |
511 | .notify.context = b, | |
512 | .client = b->c->dm_io, | |
513 | }; | |
514 | struct dm_io_region region = { | |
515 | .bdev = b->c->bdev, | |
516 | .sector = block << b->c->sectors_per_block_bits, | |
517 | .count = b->c->block_size >> SECTOR_SHIFT, | |
518 | }; | |
519 | ||
520 | if (b->data_mode != DATA_MODE_VMALLOC) { | |
521 | io_req.mem.type = DM_IO_KMEM; | |
522 | io_req.mem.ptr.addr = b->data; | |
523 | } else { | |
524 | io_req.mem.type = DM_IO_VMA; | |
525 | io_req.mem.ptr.vma = b->data; | |
526 | } | |
527 | ||
528 | b->bio.bi_end_io = end_io; | |
529 | ||
530 | r = dm_io(&io_req, 1, ®ion, NULL); | |
531 | if (r) | |
532 | end_io(&b->bio, r); | |
533 | } | |
534 | ||
535 | static void use_inline_bio(struct dm_buffer *b, int rw, sector_t block, | |
536 | bio_end_io_t *end_io) | |
537 | { | |
538 | char *ptr; | |
539 | int len; | |
540 | ||
541 | bio_init(&b->bio); | |
542 | b->bio.bi_io_vec = b->bio_vec; | |
543 | b->bio.bi_max_vecs = DM_BUFIO_INLINE_VECS; | |
4f024f37 | 544 | b->bio.bi_iter.bi_sector = block << b->c->sectors_per_block_bits; |
95d402f0 MP |
545 | b->bio.bi_bdev = b->c->bdev; |
546 | b->bio.bi_end_io = end_io; | |
547 | ||
548 | /* | |
549 | * We assume that if len >= PAGE_SIZE ptr is page-aligned. | |
550 | * If len < PAGE_SIZE the buffer doesn't cross page boundary. | |
551 | */ | |
552 | ptr = b->data; | |
553 | len = b->c->block_size; | |
554 | ||
555 | if (len >= PAGE_SIZE) | |
556 | BUG_ON((unsigned long)ptr & (PAGE_SIZE - 1)); | |
557 | else | |
558 | BUG_ON((unsigned long)ptr & (len - 1)); | |
559 | ||
560 | do { | |
561 | if (!bio_add_page(&b->bio, virt_to_page(ptr), | |
562 | len < PAGE_SIZE ? len : PAGE_SIZE, | |
563 | virt_to_phys(ptr) & (PAGE_SIZE - 1))) { | |
564 | BUG_ON(b->c->block_size <= PAGE_SIZE); | |
565 | use_dmio(b, rw, block, end_io); | |
566 | return; | |
567 | } | |
568 | ||
569 | len -= PAGE_SIZE; | |
570 | ptr += PAGE_SIZE; | |
571 | } while (len > 0); | |
572 | ||
573 | submit_bio(rw, &b->bio); | |
574 | } | |
575 | ||
576 | static void submit_io(struct dm_buffer *b, int rw, sector_t block, | |
577 | bio_end_io_t *end_io) | |
578 | { | |
579 | if (rw == WRITE && b->c->write_callback) | |
580 | b->c->write_callback(b); | |
581 | ||
582 | if (b->c->block_size <= DM_BUFIO_INLINE_VECS * PAGE_SIZE && | |
583 | b->data_mode != DATA_MODE_VMALLOC) | |
584 | use_inline_bio(b, rw, block, end_io); | |
585 | else | |
586 | use_dmio(b, rw, block, end_io); | |
587 | } | |
588 | ||
589 | /*---------------------------------------------------------------- | |
590 | * Writing dirty buffers | |
591 | *--------------------------------------------------------------*/ | |
592 | ||
593 | /* | |
594 | * The endio routine for write. | |
595 | * | |
596 | * Set the error, clear B_WRITING bit and wake anyone who was waiting on | |
597 | * it. | |
598 | */ | |
599 | static void write_endio(struct bio *bio, int error) | |
600 | { | |
601 | struct dm_buffer *b = container_of(bio, struct dm_buffer, bio); | |
602 | ||
603 | b->write_error = error; | |
a66cc28f | 604 | if (unlikely(error)) { |
95d402f0 MP |
605 | struct dm_bufio_client *c = b->c; |
606 | (void)cmpxchg(&c->async_write_error, 0, error); | |
607 | } | |
608 | ||
609 | BUG_ON(!test_bit(B_WRITING, &b->state)); | |
610 | ||
4e857c58 | 611 | smp_mb__before_atomic(); |
95d402f0 | 612 | clear_bit(B_WRITING, &b->state); |
4e857c58 | 613 | smp_mb__after_atomic(); |
95d402f0 MP |
614 | |
615 | wake_up_bit(&b->state, B_WRITING); | |
616 | } | |
617 | ||
95d402f0 MP |
618 | /* |
619 | * Initiate a write on a dirty buffer, but don't wait for it. | |
620 | * | |
621 | * - If the buffer is not dirty, exit. | |
622 | * - If there some previous write going on, wait for it to finish (we can't | |
623 | * have two writes on the same buffer simultaneously). | |
624 | * - Submit our write and don't wait on it. We set B_WRITING indicating | |
625 | * that there is a write in progress. | |
626 | */ | |
2480945c MP |
627 | static void __write_dirty_buffer(struct dm_buffer *b, |
628 | struct list_head *write_list) | |
95d402f0 MP |
629 | { |
630 | if (!test_bit(B_DIRTY, &b->state)) | |
631 | return; | |
632 | ||
633 | clear_bit(B_DIRTY, &b->state); | |
74316201 | 634 | wait_on_bit_lock_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE); |
95d402f0 | 635 | |
2480945c MP |
636 | if (!write_list) |
637 | submit_io(b, WRITE, b->block, write_endio); | |
638 | else | |
639 | list_add_tail(&b->write_list, write_list); | |
640 | } | |
641 | ||
642 | static void __flush_write_list(struct list_head *write_list) | |
643 | { | |
644 | struct blk_plug plug; | |
645 | blk_start_plug(&plug); | |
646 | while (!list_empty(write_list)) { | |
647 | struct dm_buffer *b = | |
648 | list_entry(write_list->next, struct dm_buffer, write_list); | |
649 | list_del(&b->write_list); | |
650 | submit_io(b, WRITE, b->block, write_endio); | |
651 | dm_bufio_cond_resched(); | |
652 | } | |
653 | blk_finish_plug(&plug); | |
95d402f0 MP |
654 | } |
655 | ||
656 | /* | |
657 | * Wait until any activity on the buffer finishes. Possibly write the | |
658 | * buffer if it is dirty. When this function finishes, there is no I/O | |
659 | * running on the buffer and the buffer is not dirty. | |
660 | */ | |
661 | static void __make_buffer_clean(struct dm_buffer *b) | |
662 | { | |
663 | BUG_ON(b->hold_count); | |
664 | ||
665 | if (!b->state) /* fast case */ | |
666 | return; | |
667 | ||
74316201 | 668 | wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE); |
2480945c | 669 | __write_dirty_buffer(b, NULL); |
74316201 | 670 | wait_on_bit_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE); |
95d402f0 MP |
671 | } |
672 | ||
673 | /* | |
674 | * Find some buffer that is not held by anybody, clean it, unlink it and | |
675 | * return it. | |
676 | */ | |
677 | static struct dm_buffer *__get_unclaimed_buffer(struct dm_bufio_client *c) | |
678 | { | |
679 | struct dm_buffer *b; | |
680 | ||
681 | list_for_each_entry_reverse(b, &c->lru[LIST_CLEAN], lru_list) { | |
682 | BUG_ON(test_bit(B_WRITING, &b->state)); | |
683 | BUG_ON(test_bit(B_DIRTY, &b->state)); | |
684 | ||
685 | if (!b->hold_count) { | |
686 | __make_buffer_clean(b); | |
687 | __unlink_buffer(b); | |
688 | return b; | |
689 | } | |
690 | dm_bufio_cond_resched(); | |
691 | } | |
692 | ||
693 | list_for_each_entry_reverse(b, &c->lru[LIST_DIRTY], lru_list) { | |
694 | BUG_ON(test_bit(B_READING, &b->state)); | |
695 | ||
696 | if (!b->hold_count) { | |
697 | __make_buffer_clean(b); | |
698 | __unlink_buffer(b); | |
699 | return b; | |
700 | } | |
701 | dm_bufio_cond_resched(); | |
702 | } | |
703 | ||
704 | return NULL; | |
705 | } | |
706 | ||
707 | /* | |
708 | * Wait until some other threads free some buffer or release hold count on | |
709 | * some buffer. | |
710 | * | |
711 | * This function is entered with c->lock held, drops it and regains it | |
712 | * before exiting. | |
713 | */ | |
714 | static void __wait_for_free_buffer(struct dm_bufio_client *c) | |
715 | { | |
716 | DECLARE_WAITQUEUE(wait, current); | |
717 | ||
718 | add_wait_queue(&c->free_buffer_wait, &wait); | |
719 | set_task_state(current, TASK_UNINTERRUPTIBLE); | |
720 | dm_bufio_unlock(c); | |
721 | ||
722 | io_schedule(); | |
723 | ||
724 | set_task_state(current, TASK_RUNNING); | |
725 | remove_wait_queue(&c->free_buffer_wait, &wait); | |
726 | ||
727 | dm_bufio_lock(c); | |
728 | } | |
729 | ||
a66cc28f MP |
730 | enum new_flag { |
731 | NF_FRESH = 0, | |
732 | NF_READ = 1, | |
733 | NF_GET = 2, | |
734 | NF_PREFETCH = 3 | |
735 | }; | |
736 | ||
95d402f0 MP |
737 | /* |
738 | * Allocate a new buffer. If the allocation is not possible, wait until | |
739 | * some other thread frees a buffer. | |
740 | * | |
741 | * May drop the lock and regain it. | |
742 | */ | |
a66cc28f | 743 | static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client *c, enum new_flag nf) |
95d402f0 MP |
744 | { |
745 | struct dm_buffer *b; | |
746 | ||
747 | /* | |
748 | * dm-bufio is resistant to allocation failures (it just keeps | |
749 | * one buffer reserved in cases all the allocations fail). | |
750 | * So set flags to not try too hard: | |
751 | * GFP_NOIO: don't recurse into the I/O layer | |
752 | * __GFP_NORETRY: don't retry and rather return failure | |
753 | * __GFP_NOMEMALLOC: don't use emergency reserves | |
754 | * __GFP_NOWARN: don't print a warning in case of failure | |
755 | * | |
756 | * For debugging, if we set the cache size to 1, no new buffers will | |
757 | * be allocated. | |
758 | */ | |
759 | while (1) { | |
760 | if (dm_bufio_cache_size_latch != 1) { | |
761 | b = alloc_buffer(c, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); | |
762 | if (b) | |
763 | return b; | |
764 | } | |
765 | ||
a66cc28f MP |
766 | if (nf == NF_PREFETCH) |
767 | return NULL; | |
768 | ||
95d402f0 MP |
769 | if (!list_empty(&c->reserved_buffers)) { |
770 | b = list_entry(c->reserved_buffers.next, | |
771 | struct dm_buffer, lru_list); | |
772 | list_del(&b->lru_list); | |
773 | c->need_reserved_buffers++; | |
774 | ||
775 | return b; | |
776 | } | |
777 | ||
778 | b = __get_unclaimed_buffer(c); | |
779 | if (b) | |
780 | return b; | |
781 | ||
782 | __wait_for_free_buffer(c); | |
783 | } | |
784 | } | |
785 | ||
a66cc28f | 786 | static struct dm_buffer *__alloc_buffer_wait(struct dm_bufio_client *c, enum new_flag nf) |
95d402f0 | 787 | { |
a66cc28f MP |
788 | struct dm_buffer *b = __alloc_buffer_wait_no_callback(c, nf); |
789 | ||
790 | if (!b) | |
791 | return NULL; | |
95d402f0 MP |
792 | |
793 | if (c->alloc_callback) | |
794 | c->alloc_callback(b); | |
795 | ||
796 | return b; | |
797 | } | |
798 | ||
799 | /* | |
800 | * Free a buffer and wake other threads waiting for free buffers. | |
801 | */ | |
802 | static void __free_buffer_wake(struct dm_buffer *b) | |
803 | { | |
804 | struct dm_bufio_client *c = b->c; | |
805 | ||
806 | if (!c->need_reserved_buffers) | |
807 | free_buffer(b); | |
808 | else { | |
809 | list_add(&b->lru_list, &c->reserved_buffers); | |
810 | c->need_reserved_buffers--; | |
811 | } | |
812 | ||
813 | wake_up(&c->free_buffer_wait); | |
814 | } | |
815 | ||
2480945c MP |
816 | static void __write_dirty_buffers_async(struct dm_bufio_client *c, int no_wait, |
817 | struct list_head *write_list) | |
95d402f0 MP |
818 | { |
819 | struct dm_buffer *b, *tmp; | |
820 | ||
821 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { | |
822 | BUG_ON(test_bit(B_READING, &b->state)); | |
823 | ||
824 | if (!test_bit(B_DIRTY, &b->state) && | |
825 | !test_bit(B_WRITING, &b->state)) { | |
826 | __relink_lru(b, LIST_CLEAN); | |
827 | continue; | |
828 | } | |
829 | ||
830 | if (no_wait && test_bit(B_WRITING, &b->state)) | |
831 | return; | |
832 | ||
2480945c | 833 | __write_dirty_buffer(b, write_list); |
95d402f0 MP |
834 | dm_bufio_cond_resched(); |
835 | } | |
836 | } | |
837 | ||
838 | /* | |
839 | * Get writeback threshold and buffer limit for a given client. | |
840 | */ | |
841 | static void __get_memory_limit(struct dm_bufio_client *c, | |
842 | unsigned long *threshold_buffers, | |
843 | unsigned long *limit_buffers) | |
844 | { | |
845 | unsigned long buffers; | |
846 | ||
fe5fe906 | 847 | if (ACCESS_ONCE(dm_bufio_cache_size) != dm_bufio_cache_size_latch) { |
95d402f0 MP |
848 | mutex_lock(&dm_bufio_clients_lock); |
849 | __cache_size_refresh(); | |
850 | mutex_unlock(&dm_bufio_clients_lock); | |
851 | } | |
852 | ||
853 | buffers = dm_bufio_cache_size_per_client >> | |
854 | (c->sectors_per_block_bits + SECTOR_SHIFT); | |
855 | ||
55b082e6 MP |
856 | if (buffers < c->minimum_buffers) |
857 | buffers = c->minimum_buffers; | |
95d402f0 MP |
858 | |
859 | *limit_buffers = buffers; | |
860 | *threshold_buffers = buffers * DM_BUFIO_WRITEBACK_PERCENT / 100; | |
861 | } | |
862 | ||
863 | /* | |
864 | * Check if we're over watermark. | |
865 | * If we are over threshold_buffers, start freeing buffers. | |
866 | * If we're over "limit_buffers", block until we get under the limit. | |
867 | */ | |
2480945c MP |
868 | static void __check_watermark(struct dm_bufio_client *c, |
869 | struct list_head *write_list) | |
95d402f0 MP |
870 | { |
871 | unsigned long threshold_buffers, limit_buffers; | |
872 | ||
873 | __get_memory_limit(c, &threshold_buffers, &limit_buffers); | |
874 | ||
875 | while (c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY] > | |
876 | limit_buffers) { | |
877 | ||
878 | struct dm_buffer *b = __get_unclaimed_buffer(c); | |
879 | ||
880 | if (!b) | |
881 | return; | |
882 | ||
883 | __free_buffer_wake(b); | |
884 | dm_bufio_cond_resched(); | |
885 | } | |
886 | ||
887 | if (c->n_buffers[LIST_DIRTY] > threshold_buffers) | |
2480945c | 888 | __write_dirty_buffers_async(c, 1, write_list); |
95d402f0 MP |
889 | } |
890 | ||
891 | /* | |
892 | * Find a buffer in the hash. | |
893 | */ | |
894 | static struct dm_buffer *__find(struct dm_bufio_client *c, sector_t block) | |
895 | { | |
896 | struct dm_buffer *b; | |
95d402f0 | 897 | |
b67bfe0d | 898 | hlist_for_each_entry(b, &c->cache_hash[DM_BUFIO_HASH(block)], |
95d402f0 MP |
899 | hash_list) { |
900 | dm_bufio_cond_resched(); | |
901 | if (b->block == block) | |
902 | return b; | |
903 | } | |
904 | ||
905 | return NULL; | |
906 | } | |
907 | ||
908 | /*---------------------------------------------------------------- | |
909 | * Getting a buffer | |
910 | *--------------------------------------------------------------*/ | |
911 | ||
95d402f0 | 912 | static struct dm_buffer *__bufio_new(struct dm_bufio_client *c, sector_t block, |
2480945c MP |
913 | enum new_flag nf, int *need_submit, |
914 | struct list_head *write_list) | |
95d402f0 MP |
915 | { |
916 | struct dm_buffer *b, *new_b = NULL; | |
917 | ||
918 | *need_submit = 0; | |
919 | ||
920 | b = __find(c, block); | |
a66cc28f MP |
921 | if (b) |
922 | goto found_buffer; | |
95d402f0 MP |
923 | |
924 | if (nf == NF_GET) | |
925 | return NULL; | |
926 | ||
a66cc28f MP |
927 | new_b = __alloc_buffer_wait(c, nf); |
928 | if (!new_b) | |
929 | return NULL; | |
95d402f0 MP |
930 | |
931 | /* | |
932 | * We've had a period where the mutex was unlocked, so need to | |
933 | * recheck the hash table. | |
934 | */ | |
935 | b = __find(c, block); | |
936 | if (b) { | |
937 | __free_buffer_wake(new_b); | |
a66cc28f | 938 | goto found_buffer; |
95d402f0 MP |
939 | } |
940 | ||
2480945c | 941 | __check_watermark(c, write_list); |
95d402f0 MP |
942 | |
943 | b = new_b; | |
944 | b->hold_count = 1; | |
945 | b->read_error = 0; | |
946 | b->write_error = 0; | |
947 | __link_buffer(b, block, LIST_CLEAN); | |
948 | ||
949 | if (nf == NF_FRESH) { | |
950 | b->state = 0; | |
951 | return b; | |
952 | } | |
953 | ||
954 | b->state = 1 << B_READING; | |
955 | *need_submit = 1; | |
956 | ||
957 | return b; | |
a66cc28f MP |
958 | |
959 | found_buffer: | |
960 | if (nf == NF_PREFETCH) | |
961 | return NULL; | |
962 | /* | |
963 | * Note: it is essential that we don't wait for the buffer to be | |
964 | * read if dm_bufio_get function is used. Both dm_bufio_get and | |
965 | * dm_bufio_prefetch can be used in the driver request routine. | |
966 | * If the user called both dm_bufio_prefetch and dm_bufio_get on | |
967 | * the same buffer, it would deadlock if we waited. | |
968 | */ | |
969 | if (nf == NF_GET && unlikely(test_bit(B_READING, &b->state))) | |
970 | return NULL; | |
971 | ||
972 | b->hold_count++; | |
973 | __relink_lru(b, test_bit(B_DIRTY, &b->state) || | |
974 | test_bit(B_WRITING, &b->state)); | |
975 | return b; | |
95d402f0 MP |
976 | } |
977 | ||
978 | /* | |
979 | * The endio routine for reading: set the error, clear the bit and wake up | |
980 | * anyone waiting on the buffer. | |
981 | */ | |
982 | static void read_endio(struct bio *bio, int error) | |
983 | { | |
984 | struct dm_buffer *b = container_of(bio, struct dm_buffer, bio); | |
985 | ||
986 | b->read_error = error; | |
987 | ||
988 | BUG_ON(!test_bit(B_READING, &b->state)); | |
989 | ||
4e857c58 | 990 | smp_mb__before_atomic(); |
95d402f0 | 991 | clear_bit(B_READING, &b->state); |
4e857c58 | 992 | smp_mb__after_atomic(); |
95d402f0 MP |
993 | |
994 | wake_up_bit(&b->state, B_READING); | |
995 | } | |
996 | ||
997 | /* | |
998 | * A common routine for dm_bufio_new and dm_bufio_read. Operation of these | |
999 | * functions is similar except that dm_bufio_new doesn't read the | |
1000 | * buffer from the disk (assuming that the caller overwrites all the data | |
1001 | * and uses dm_bufio_mark_buffer_dirty to write new data back). | |
1002 | */ | |
1003 | static void *new_read(struct dm_bufio_client *c, sector_t block, | |
1004 | enum new_flag nf, struct dm_buffer **bp) | |
1005 | { | |
1006 | int need_submit; | |
1007 | struct dm_buffer *b; | |
1008 | ||
2480945c MP |
1009 | LIST_HEAD(write_list); |
1010 | ||
95d402f0 | 1011 | dm_bufio_lock(c); |
2480945c | 1012 | b = __bufio_new(c, block, nf, &need_submit, &write_list); |
95d402f0 MP |
1013 | dm_bufio_unlock(c); |
1014 | ||
2480945c MP |
1015 | __flush_write_list(&write_list); |
1016 | ||
a66cc28f | 1017 | if (!b) |
95d402f0 MP |
1018 | return b; |
1019 | ||
1020 | if (need_submit) | |
1021 | submit_io(b, READ, b->block, read_endio); | |
1022 | ||
74316201 | 1023 | wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE); |
95d402f0 MP |
1024 | |
1025 | if (b->read_error) { | |
1026 | int error = b->read_error; | |
1027 | ||
1028 | dm_bufio_release(b); | |
1029 | ||
1030 | return ERR_PTR(error); | |
1031 | } | |
1032 | ||
1033 | *bp = b; | |
1034 | ||
1035 | return b->data; | |
1036 | } | |
1037 | ||
1038 | void *dm_bufio_get(struct dm_bufio_client *c, sector_t block, | |
1039 | struct dm_buffer **bp) | |
1040 | { | |
1041 | return new_read(c, block, NF_GET, bp); | |
1042 | } | |
1043 | EXPORT_SYMBOL_GPL(dm_bufio_get); | |
1044 | ||
1045 | void *dm_bufio_read(struct dm_bufio_client *c, sector_t block, | |
1046 | struct dm_buffer **bp) | |
1047 | { | |
1048 | BUG_ON(dm_bufio_in_request()); | |
1049 | ||
1050 | return new_read(c, block, NF_READ, bp); | |
1051 | } | |
1052 | EXPORT_SYMBOL_GPL(dm_bufio_read); | |
1053 | ||
1054 | void *dm_bufio_new(struct dm_bufio_client *c, sector_t block, | |
1055 | struct dm_buffer **bp) | |
1056 | { | |
1057 | BUG_ON(dm_bufio_in_request()); | |
1058 | ||
1059 | return new_read(c, block, NF_FRESH, bp); | |
1060 | } | |
1061 | EXPORT_SYMBOL_GPL(dm_bufio_new); | |
1062 | ||
a66cc28f MP |
1063 | void dm_bufio_prefetch(struct dm_bufio_client *c, |
1064 | sector_t block, unsigned n_blocks) | |
1065 | { | |
1066 | struct blk_plug plug; | |
1067 | ||
2480945c MP |
1068 | LIST_HEAD(write_list); |
1069 | ||
3b6b7813 MP |
1070 | BUG_ON(dm_bufio_in_request()); |
1071 | ||
a66cc28f MP |
1072 | blk_start_plug(&plug); |
1073 | dm_bufio_lock(c); | |
1074 | ||
1075 | for (; n_blocks--; block++) { | |
1076 | int need_submit; | |
1077 | struct dm_buffer *b; | |
2480945c MP |
1078 | b = __bufio_new(c, block, NF_PREFETCH, &need_submit, |
1079 | &write_list); | |
1080 | if (unlikely(!list_empty(&write_list))) { | |
1081 | dm_bufio_unlock(c); | |
1082 | blk_finish_plug(&plug); | |
1083 | __flush_write_list(&write_list); | |
1084 | blk_start_plug(&plug); | |
1085 | dm_bufio_lock(c); | |
1086 | } | |
a66cc28f MP |
1087 | if (unlikely(b != NULL)) { |
1088 | dm_bufio_unlock(c); | |
1089 | ||
1090 | if (need_submit) | |
1091 | submit_io(b, READ, b->block, read_endio); | |
1092 | dm_bufio_release(b); | |
1093 | ||
1094 | dm_bufio_cond_resched(); | |
1095 | ||
1096 | if (!n_blocks) | |
1097 | goto flush_plug; | |
1098 | dm_bufio_lock(c); | |
1099 | } | |
a66cc28f MP |
1100 | } |
1101 | ||
1102 | dm_bufio_unlock(c); | |
1103 | ||
1104 | flush_plug: | |
1105 | blk_finish_plug(&plug); | |
1106 | } | |
1107 | EXPORT_SYMBOL_GPL(dm_bufio_prefetch); | |
1108 | ||
95d402f0 MP |
1109 | void dm_bufio_release(struct dm_buffer *b) |
1110 | { | |
1111 | struct dm_bufio_client *c = b->c; | |
1112 | ||
1113 | dm_bufio_lock(c); | |
1114 | ||
95d402f0 MP |
1115 | BUG_ON(!b->hold_count); |
1116 | ||
1117 | b->hold_count--; | |
1118 | if (!b->hold_count) { | |
1119 | wake_up(&c->free_buffer_wait); | |
1120 | ||
1121 | /* | |
1122 | * If there were errors on the buffer, and the buffer is not | |
1123 | * to be written, free the buffer. There is no point in caching | |
1124 | * invalid buffer. | |
1125 | */ | |
1126 | if ((b->read_error || b->write_error) && | |
a66cc28f | 1127 | !test_bit(B_READING, &b->state) && |
95d402f0 MP |
1128 | !test_bit(B_WRITING, &b->state) && |
1129 | !test_bit(B_DIRTY, &b->state)) { | |
1130 | __unlink_buffer(b); | |
1131 | __free_buffer_wake(b); | |
1132 | } | |
1133 | } | |
1134 | ||
1135 | dm_bufio_unlock(c); | |
1136 | } | |
1137 | EXPORT_SYMBOL_GPL(dm_bufio_release); | |
1138 | ||
1139 | void dm_bufio_mark_buffer_dirty(struct dm_buffer *b) | |
1140 | { | |
1141 | struct dm_bufio_client *c = b->c; | |
1142 | ||
1143 | dm_bufio_lock(c); | |
1144 | ||
a66cc28f MP |
1145 | BUG_ON(test_bit(B_READING, &b->state)); |
1146 | ||
95d402f0 MP |
1147 | if (!test_and_set_bit(B_DIRTY, &b->state)) |
1148 | __relink_lru(b, LIST_DIRTY); | |
1149 | ||
1150 | dm_bufio_unlock(c); | |
1151 | } | |
1152 | EXPORT_SYMBOL_GPL(dm_bufio_mark_buffer_dirty); | |
1153 | ||
1154 | void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c) | |
1155 | { | |
2480945c MP |
1156 | LIST_HEAD(write_list); |
1157 | ||
95d402f0 MP |
1158 | BUG_ON(dm_bufio_in_request()); |
1159 | ||
1160 | dm_bufio_lock(c); | |
2480945c | 1161 | __write_dirty_buffers_async(c, 0, &write_list); |
95d402f0 | 1162 | dm_bufio_unlock(c); |
2480945c | 1163 | __flush_write_list(&write_list); |
95d402f0 MP |
1164 | } |
1165 | EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers_async); | |
1166 | ||
1167 | /* | |
1168 | * For performance, it is essential that the buffers are written asynchronously | |
1169 | * and simultaneously (so that the block layer can merge the writes) and then | |
1170 | * waited upon. | |
1171 | * | |
1172 | * Finally, we flush hardware disk cache. | |
1173 | */ | |
1174 | int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c) | |
1175 | { | |
1176 | int a, f; | |
1177 | unsigned long buffers_processed = 0; | |
1178 | struct dm_buffer *b, *tmp; | |
1179 | ||
2480945c MP |
1180 | LIST_HEAD(write_list); |
1181 | ||
1182 | dm_bufio_lock(c); | |
1183 | __write_dirty_buffers_async(c, 0, &write_list); | |
1184 | dm_bufio_unlock(c); | |
1185 | __flush_write_list(&write_list); | |
95d402f0 | 1186 | dm_bufio_lock(c); |
95d402f0 MP |
1187 | |
1188 | again: | |
1189 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { | |
1190 | int dropped_lock = 0; | |
1191 | ||
1192 | if (buffers_processed < c->n_buffers[LIST_DIRTY]) | |
1193 | buffers_processed++; | |
1194 | ||
1195 | BUG_ON(test_bit(B_READING, &b->state)); | |
1196 | ||
1197 | if (test_bit(B_WRITING, &b->state)) { | |
1198 | if (buffers_processed < c->n_buffers[LIST_DIRTY]) { | |
1199 | dropped_lock = 1; | |
1200 | b->hold_count++; | |
1201 | dm_bufio_unlock(c); | |
74316201 N |
1202 | wait_on_bit_io(&b->state, B_WRITING, |
1203 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1204 | dm_bufio_lock(c); |
1205 | b->hold_count--; | |
1206 | } else | |
74316201 N |
1207 | wait_on_bit_io(&b->state, B_WRITING, |
1208 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1209 | } |
1210 | ||
1211 | if (!test_bit(B_DIRTY, &b->state) && | |
1212 | !test_bit(B_WRITING, &b->state)) | |
1213 | __relink_lru(b, LIST_CLEAN); | |
1214 | ||
1215 | dm_bufio_cond_resched(); | |
1216 | ||
1217 | /* | |
1218 | * If we dropped the lock, the list is no longer consistent, | |
1219 | * so we must restart the search. | |
1220 | * | |
1221 | * In the most common case, the buffer just processed is | |
1222 | * relinked to the clean list, so we won't loop scanning the | |
1223 | * same buffer again and again. | |
1224 | * | |
1225 | * This may livelock if there is another thread simultaneously | |
1226 | * dirtying buffers, so we count the number of buffers walked | |
1227 | * and if it exceeds the total number of buffers, it means that | |
1228 | * someone is doing some writes simultaneously with us. In | |
1229 | * this case, stop, dropping the lock. | |
1230 | */ | |
1231 | if (dropped_lock) | |
1232 | goto again; | |
1233 | } | |
1234 | wake_up(&c->free_buffer_wait); | |
1235 | dm_bufio_unlock(c); | |
1236 | ||
1237 | a = xchg(&c->async_write_error, 0); | |
1238 | f = dm_bufio_issue_flush(c); | |
1239 | if (a) | |
1240 | return a; | |
1241 | ||
1242 | return f; | |
1243 | } | |
1244 | EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers); | |
1245 | ||
1246 | /* | |
1247 | * Use dm-io to send and empty barrier flush the device. | |
1248 | */ | |
1249 | int dm_bufio_issue_flush(struct dm_bufio_client *c) | |
1250 | { | |
1251 | struct dm_io_request io_req = { | |
3daec3b4 | 1252 | .bi_rw = WRITE_FLUSH, |
95d402f0 MP |
1253 | .mem.type = DM_IO_KMEM, |
1254 | .mem.ptr.addr = NULL, | |
1255 | .client = c->dm_io, | |
1256 | }; | |
1257 | struct dm_io_region io_reg = { | |
1258 | .bdev = c->bdev, | |
1259 | .sector = 0, | |
1260 | .count = 0, | |
1261 | }; | |
1262 | ||
1263 | BUG_ON(dm_bufio_in_request()); | |
1264 | ||
1265 | return dm_io(&io_req, 1, &io_reg, NULL); | |
1266 | } | |
1267 | EXPORT_SYMBOL_GPL(dm_bufio_issue_flush); | |
1268 | ||
1269 | /* | |
1270 | * We first delete any other buffer that may be at that new location. | |
1271 | * | |
1272 | * Then, we write the buffer to the original location if it was dirty. | |
1273 | * | |
1274 | * Then, if we are the only one who is holding the buffer, relink the buffer | |
1275 | * in the hash queue for the new location. | |
1276 | * | |
1277 | * If there was someone else holding the buffer, we write it to the new | |
1278 | * location but not relink it, because that other user needs to have the buffer | |
1279 | * at the same place. | |
1280 | */ | |
1281 | void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block) | |
1282 | { | |
1283 | struct dm_bufio_client *c = b->c; | |
1284 | struct dm_buffer *new; | |
1285 | ||
1286 | BUG_ON(dm_bufio_in_request()); | |
1287 | ||
1288 | dm_bufio_lock(c); | |
1289 | ||
1290 | retry: | |
1291 | new = __find(c, new_block); | |
1292 | if (new) { | |
1293 | if (new->hold_count) { | |
1294 | __wait_for_free_buffer(c); | |
1295 | goto retry; | |
1296 | } | |
1297 | ||
1298 | /* | |
1299 | * FIXME: Is there any point waiting for a write that's going | |
1300 | * to be overwritten in a bit? | |
1301 | */ | |
1302 | __make_buffer_clean(new); | |
1303 | __unlink_buffer(new); | |
1304 | __free_buffer_wake(new); | |
1305 | } | |
1306 | ||
1307 | BUG_ON(!b->hold_count); | |
1308 | BUG_ON(test_bit(B_READING, &b->state)); | |
1309 | ||
2480945c | 1310 | __write_dirty_buffer(b, NULL); |
95d402f0 | 1311 | if (b->hold_count == 1) { |
74316201 N |
1312 | wait_on_bit_io(&b->state, B_WRITING, |
1313 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1314 | set_bit(B_DIRTY, &b->state); |
1315 | __unlink_buffer(b); | |
1316 | __link_buffer(b, new_block, LIST_DIRTY); | |
1317 | } else { | |
1318 | sector_t old_block; | |
74316201 N |
1319 | wait_on_bit_lock_io(&b->state, B_WRITING, |
1320 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1321 | /* |
1322 | * Relink buffer to "new_block" so that write_callback | |
1323 | * sees "new_block" as a block number. | |
1324 | * After the write, link the buffer back to old_block. | |
1325 | * All this must be done in bufio lock, so that block number | |
1326 | * change isn't visible to other threads. | |
1327 | */ | |
1328 | old_block = b->block; | |
1329 | __unlink_buffer(b); | |
1330 | __link_buffer(b, new_block, b->list_mode); | |
1331 | submit_io(b, WRITE, new_block, write_endio); | |
74316201 N |
1332 | wait_on_bit_io(&b->state, B_WRITING, |
1333 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1334 | __unlink_buffer(b); |
1335 | __link_buffer(b, old_block, b->list_mode); | |
1336 | } | |
1337 | ||
1338 | dm_bufio_unlock(c); | |
1339 | dm_bufio_release(b); | |
1340 | } | |
1341 | EXPORT_SYMBOL_GPL(dm_bufio_release_move); | |
1342 | ||
55494bf2 MP |
1343 | /* |
1344 | * Free the given buffer. | |
1345 | * | |
1346 | * This is just a hint, if the buffer is in use or dirty, this function | |
1347 | * does nothing. | |
1348 | */ | |
1349 | void dm_bufio_forget(struct dm_bufio_client *c, sector_t block) | |
1350 | { | |
1351 | struct dm_buffer *b; | |
1352 | ||
1353 | dm_bufio_lock(c); | |
1354 | ||
1355 | b = __find(c, block); | |
1356 | if (b && likely(!b->hold_count) && likely(!b->state)) { | |
1357 | __unlink_buffer(b); | |
1358 | __free_buffer_wake(b); | |
1359 | } | |
1360 | ||
1361 | dm_bufio_unlock(c); | |
1362 | } | |
1363 | EXPORT_SYMBOL(dm_bufio_forget); | |
1364 | ||
55b082e6 MP |
1365 | void dm_bufio_set_minimum_buffers(struct dm_bufio_client *c, unsigned n) |
1366 | { | |
1367 | c->minimum_buffers = n; | |
1368 | } | |
1369 | EXPORT_SYMBOL(dm_bufio_set_minimum_buffers); | |
1370 | ||
95d402f0 MP |
1371 | unsigned dm_bufio_get_block_size(struct dm_bufio_client *c) |
1372 | { | |
1373 | return c->block_size; | |
1374 | } | |
1375 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_size); | |
1376 | ||
1377 | sector_t dm_bufio_get_device_size(struct dm_bufio_client *c) | |
1378 | { | |
1379 | return i_size_read(c->bdev->bd_inode) >> | |
1380 | (SECTOR_SHIFT + c->sectors_per_block_bits); | |
1381 | } | |
1382 | EXPORT_SYMBOL_GPL(dm_bufio_get_device_size); | |
1383 | ||
1384 | sector_t dm_bufio_get_block_number(struct dm_buffer *b) | |
1385 | { | |
1386 | return b->block; | |
1387 | } | |
1388 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_number); | |
1389 | ||
1390 | void *dm_bufio_get_block_data(struct dm_buffer *b) | |
1391 | { | |
1392 | return b->data; | |
1393 | } | |
1394 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_data); | |
1395 | ||
1396 | void *dm_bufio_get_aux_data(struct dm_buffer *b) | |
1397 | { | |
1398 | return b + 1; | |
1399 | } | |
1400 | EXPORT_SYMBOL_GPL(dm_bufio_get_aux_data); | |
1401 | ||
1402 | struct dm_bufio_client *dm_bufio_get_client(struct dm_buffer *b) | |
1403 | { | |
1404 | return b->c; | |
1405 | } | |
1406 | EXPORT_SYMBOL_GPL(dm_bufio_get_client); | |
1407 | ||
1408 | static void drop_buffers(struct dm_bufio_client *c) | |
1409 | { | |
1410 | struct dm_buffer *b; | |
1411 | int i; | |
1412 | ||
1413 | BUG_ON(dm_bufio_in_request()); | |
1414 | ||
1415 | /* | |
1416 | * An optimization so that the buffers are not written one-by-one. | |
1417 | */ | |
1418 | dm_bufio_write_dirty_buffers_async(c); | |
1419 | ||
1420 | dm_bufio_lock(c); | |
1421 | ||
1422 | while ((b = __get_unclaimed_buffer(c))) | |
1423 | __free_buffer_wake(b); | |
1424 | ||
1425 | for (i = 0; i < LIST_SIZE; i++) | |
1426 | list_for_each_entry(b, &c->lru[i], lru_list) | |
1427 | DMERR("leaked buffer %llx, hold count %u, list %d", | |
1428 | (unsigned long long)b->block, b->hold_count, i); | |
1429 | ||
1430 | for (i = 0; i < LIST_SIZE; i++) | |
1431 | BUG_ON(!list_empty(&c->lru[i])); | |
1432 | ||
1433 | dm_bufio_unlock(c); | |
1434 | } | |
1435 | ||
1436 | /* | |
1437 | * Test if the buffer is unused and too old, and commit it. | |
1438 | * At if noio is set, we must not do any I/O because we hold | |
1439 | * dm_bufio_clients_lock and we would risk deadlock if the I/O gets rerouted to | |
1440 | * different bufio client. | |
1441 | */ | |
1442 | static int __cleanup_old_buffer(struct dm_buffer *b, gfp_t gfp, | |
1443 | unsigned long max_jiffies) | |
1444 | { | |
1445 | if (jiffies - b->last_accessed < max_jiffies) | |
7dc19d5a | 1446 | return 0; |
95d402f0 MP |
1447 | |
1448 | if (!(gfp & __GFP_IO)) { | |
1449 | if (test_bit(B_READING, &b->state) || | |
1450 | test_bit(B_WRITING, &b->state) || | |
1451 | test_bit(B_DIRTY, &b->state)) | |
7dc19d5a | 1452 | return 0; |
95d402f0 MP |
1453 | } |
1454 | ||
1455 | if (b->hold_count) | |
7dc19d5a | 1456 | return 0; |
95d402f0 MP |
1457 | |
1458 | __make_buffer_clean(b); | |
1459 | __unlink_buffer(b); | |
1460 | __free_buffer_wake(b); | |
1461 | ||
7dc19d5a | 1462 | return 1; |
95d402f0 MP |
1463 | } |
1464 | ||
7dc19d5a DC |
1465 | static long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan, |
1466 | gfp_t gfp_mask) | |
95d402f0 MP |
1467 | { |
1468 | int l; | |
1469 | struct dm_buffer *b, *tmp; | |
7dc19d5a | 1470 | long freed = 0; |
95d402f0 MP |
1471 | |
1472 | for (l = 0; l < LIST_SIZE; l++) { | |
7dc19d5a DC |
1473 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list) { |
1474 | freed += __cleanup_old_buffer(b, gfp_mask, 0); | |
1475 | if (!--nr_to_scan) | |
0e825862 MP |
1476 | return freed; |
1477 | dm_bufio_cond_resched(); | |
7dc19d5a | 1478 | } |
95d402f0 | 1479 | } |
7dc19d5a | 1480 | return freed; |
95d402f0 MP |
1481 | } |
1482 | ||
7dc19d5a DC |
1483 | static unsigned long |
1484 | dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) | |
95d402f0 | 1485 | { |
7dc19d5a DC |
1486 | struct dm_bufio_client *c; |
1487 | unsigned long freed; | |
95d402f0 | 1488 | |
7dc19d5a | 1489 | c = container_of(shrink, struct dm_bufio_client, shrinker); |
95d402f0 MP |
1490 | if (sc->gfp_mask & __GFP_IO) |
1491 | dm_bufio_lock(c); | |
1492 | else if (!dm_bufio_trylock(c)) | |
7dc19d5a | 1493 | return SHRINK_STOP; |
95d402f0 | 1494 | |
7dc19d5a DC |
1495 | freed = __scan(c, sc->nr_to_scan, sc->gfp_mask); |
1496 | dm_bufio_unlock(c); | |
1497 | return freed; | |
1498 | } | |
95d402f0 | 1499 | |
7dc19d5a DC |
1500 | static unsigned long |
1501 | dm_bufio_shrink_count(struct shrinker *shrink, struct shrink_control *sc) | |
1502 | { | |
1503 | struct dm_bufio_client *c; | |
1504 | unsigned long count; | |
95d402f0 | 1505 | |
7dc19d5a DC |
1506 | c = container_of(shrink, struct dm_bufio_client, shrinker); |
1507 | if (sc->gfp_mask & __GFP_IO) | |
1508 | dm_bufio_lock(c); | |
1509 | else if (!dm_bufio_trylock(c)) | |
1510 | return 0; | |
95d402f0 | 1511 | |
7dc19d5a DC |
1512 | count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY]; |
1513 | dm_bufio_unlock(c); | |
1514 | return count; | |
95d402f0 MP |
1515 | } |
1516 | ||
1517 | /* | |
1518 | * Create the buffering interface | |
1519 | */ | |
1520 | struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsigned block_size, | |
1521 | unsigned reserved_buffers, unsigned aux_size, | |
1522 | void (*alloc_callback)(struct dm_buffer *), | |
1523 | void (*write_callback)(struct dm_buffer *)) | |
1524 | { | |
1525 | int r; | |
1526 | struct dm_bufio_client *c; | |
1527 | unsigned i; | |
1528 | ||
1529 | BUG_ON(block_size < 1 << SECTOR_SHIFT || | |
1530 | (block_size & (block_size - 1))); | |
1531 | ||
d8c712ea | 1532 | c = kzalloc(sizeof(*c), GFP_KERNEL); |
95d402f0 MP |
1533 | if (!c) { |
1534 | r = -ENOMEM; | |
1535 | goto bad_client; | |
1536 | } | |
1537 | c->cache_hash = vmalloc(sizeof(struct hlist_head) << DM_BUFIO_HASH_BITS); | |
1538 | if (!c->cache_hash) { | |
1539 | r = -ENOMEM; | |
1540 | goto bad_hash; | |
1541 | } | |
1542 | ||
1543 | c->bdev = bdev; | |
1544 | c->block_size = block_size; | |
1545 | c->sectors_per_block_bits = ffs(block_size) - 1 - SECTOR_SHIFT; | |
1546 | c->pages_per_block_bits = (ffs(block_size) - 1 >= PAGE_SHIFT) ? | |
1547 | ffs(block_size) - 1 - PAGE_SHIFT : 0; | |
1548 | c->blocks_per_page_bits = (ffs(block_size) - 1 < PAGE_SHIFT ? | |
1549 | PAGE_SHIFT - (ffs(block_size) - 1) : 0); | |
1550 | ||
1551 | c->aux_size = aux_size; | |
1552 | c->alloc_callback = alloc_callback; | |
1553 | c->write_callback = write_callback; | |
1554 | ||
1555 | for (i = 0; i < LIST_SIZE; i++) { | |
1556 | INIT_LIST_HEAD(&c->lru[i]); | |
1557 | c->n_buffers[i] = 0; | |
1558 | } | |
1559 | ||
1560 | for (i = 0; i < 1 << DM_BUFIO_HASH_BITS; i++) | |
1561 | INIT_HLIST_HEAD(&c->cache_hash[i]); | |
1562 | ||
1563 | mutex_init(&c->lock); | |
1564 | INIT_LIST_HEAD(&c->reserved_buffers); | |
1565 | c->need_reserved_buffers = reserved_buffers; | |
1566 | ||
55b082e6 MP |
1567 | c->minimum_buffers = DM_BUFIO_MIN_BUFFERS; |
1568 | ||
95d402f0 MP |
1569 | init_waitqueue_head(&c->free_buffer_wait); |
1570 | c->async_write_error = 0; | |
1571 | ||
1572 | c->dm_io = dm_io_client_create(); | |
1573 | if (IS_ERR(c->dm_io)) { | |
1574 | r = PTR_ERR(c->dm_io); | |
1575 | goto bad_dm_io; | |
1576 | } | |
1577 | ||
1578 | mutex_lock(&dm_bufio_clients_lock); | |
1579 | if (c->blocks_per_page_bits) { | |
1580 | if (!DM_BUFIO_CACHE_NAME(c)) { | |
1581 | DM_BUFIO_CACHE_NAME(c) = kasprintf(GFP_KERNEL, "dm_bufio_cache-%u", c->block_size); | |
1582 | if (!DM_BUFIO_CACHE_NAME(c)) { | |
1583 | r = -ENOMEM; | |
1584 | mutex_unlock(&dm_bufio_clients_lock); | |
1585 | goto bad_cache; | |
1586 | } | |
1587 | } | |
1588 | ||
1589 | if (!DM_BUFIO_CACHE(c)) { | |
1590 | DM_BUFIO_CACHE(c) = kmem_cache_create(DM_BUFIO_CACHE_NAME(c), | |
1591 | c->block_size, | |
1592 | c->block_size, 0, NULL); | |
1593 | if (!DM_BUFIO_CACHE(c)) { | |
1594 | r = -ENOMEM; | |
1595 | mutex_unlock(&dm_bufio_clients_lock); | |
1596 | goto bad_cache; | |
1597 | } | |
1598 | } | |
1599 | } | |
1600 | mutex_unlock(&dm_bufio_clients_lock); | |
1601 | ||
1602 | while (c->need_reserved_buffers) { | |
1603 | struct dm_buffer *b = alloc_buffer(c, GFP_KERNEL); | |
1604 | ||
1605 | if (!b) { | |
1606 | r = -ENOMEM; | |
1607 | goto bad_buffer; | |
1608 | } | |
1609 | __free_buffer_wake(b); | |
1610 | } | |
1611 | ||
1612 | mutex_lock(&dm_bufio_clients_lock); | |
1613 | dm_bufio_client_count++; | |
1614 | list_add(&c->client_list, &dm_bufio_all_clients); | |
1615 | __cache_size_refresh(); | |
1616 | mutex_unlock(&dm_bufio_clients_lock); | |
1617 | ||
7dc19d5a DC |
1618 | c->shrinker.count_objects = dm_bufio_shrink_count; |
1619 | c->shrinker.scan_objects = dm_bufio_shrink_scan; | |
95d402f0 MP |
1620 | c->shrinker.seeks = 1; |
1621 | c->shrinker.batch = 0; | |
1622 | register_shrinker(&c->shrinker); | |
1623 | ||
1624 | return c; | |
1625 | ||
1626 | bad_buffer: | |
1627 | bad_cache: | |
1628 | while (!list_empty(&c->reserved_buffers)) { | |
1629 | struct dm_buffer *b = list_entry(c->reserved_buffers.next, | |
1630 | struct dm_buffer, lru_list); | |
1631 | list_del(&b->lru_list); | |
1632 | free_buffer(b); | |
1633 | } | |
1634 | dm_io_client_destroy(c->dm_io); | |
1635 | bad_dm_io: | |
1636 | vfree(c->cache_hash); | |
1637 | bad_hash: | |
1638 | kfree(c); | |
1639 | bad_client: | |
1640 | return ERR_PTR(r); | |
1641 | } | |
1642 | EXPORT_SYMBOL_GPL(dm_bufio_client_create); | |
1643 | ||
1644 | /* | |
1645 | * Free the buffering interface. | |
1646 | * It is required that there are no references on any buffers. | |
1647 | */ | |
1648 | void dm_bufio_client_destroy(struct dm_bufio_client *c) | |
1649 | { | |
1650 | unsigned i; | |
1651 | ||
1652 | drop_buffers(c); | |
1653 | ||
1654 | unregister_shrinker(&c->shrinker); | |
1655 | ||
1656 | mutex_lock(&dm_bufio_clients_lock); | |
1657 | ||
1658 | list_del(&c->client_list); | |
1659 | dm_bufio_client_count--; | |
1660 | __cache_size_refresh(); | |
1661 | ||
1662 | mutex_unlock(&dm_bufio_clients_lock); | |
1663 | ||
1664 | for (i = 0; i < 1 << DM_BUFIO_HASH_BITS; i++) | |
1665 | BUG_ON(!hlist_empty(&c->cache_hash[i])); | |
1666 | ||
1667 | BUG_ON(c->need_reserved_buffers); | |
1668 | ||
1669 | while (!list_empty(&c->reserved_buffers)) { | |
1670 | struct dm_buffer *b = list_entry(c->reserved_buffers.next, | |
1671 | struct dm_buffer, lru_list); | |
1672 | list_del(&b->lru_list); | |
1673 | free_buffer(b); | |
1674 | } | |
1675 | ||
1676 | for (i = 0; i < LIST_SIZE; i++) | |
1677 | if (c->n_buffers[i]) | |
1678 | DMERR("leaked buffer count %d: %ld", i, c->n_buffers[i]); | |
1679 | ||
1680 | for (i = 0; i < LIST_SIZE; i++) | |
1681 | BUG_ON(c->n_buffers[i]); | |
1682 | ||
1683 | dm_io_client_destroy(c->dm_io); | |
1684 | vfree(c->cache_hash); | |
1685 | kfree(c); | |
1686 | } | |
1687 | EXPORT_SYMBOL_GPL(dm_bufio_client_destroy); | |
1688 | ||
1689 | static void cleanup_old_buffers(void) | |
1690 | { | |
fe5fe906 | 1691 | unsigned long max_age = ACCESS_ONCE(dm_bufio_max_age); |
95d402f0 MP |
1692 | struct dm_bufio_client *c; |
1693 | ||
95d402f0 MP |
1694 | if (max_age > ULONG_MAX / HZ) |
1695 | max_age = ULONG_MAX / HZ; | |
1696 | ||
1697 | mutex_lock(&dm_bufio_clients_lock); | |
1698 | list_for_each_entry(c, &dm_bufio_all_clients, client_list) { | |
1699 | if (!dm_bufio_trylock(c)) | |
1700 | continue; | |
1701 | ||
1702 | while (!list_empty(&c->lru[LIST_CLEAN])) { | |
1703 | struct dm_buffer *b; | |
1704 | b = list_entry(c->lru[LIST_CLEAN].prev, | |
1705 | struct dm_buffer, lru_list); | |
7dc19d5a | 1706 | if (!__cleanup_old_buffer(b, 0, max_age * HZ)) |
95d402f0 MP |
1707 | break; |
1708 | dm_bufio_cond_resched(); | |
1709 | } | |
1710 | ||
1711 | dm_bufio_unlock(c); | |
1712 | dm_bufio_cond_resched(); | |
1713 | } | |
1714 | mutex_unlock(&dm_bufio_clients_lock); | |
1715 | } | |
1716 | ||
1717 | static struct workqueue_struct *dm_bufio_wq; | |
1718 | static struct delayed_work dm_bufio_work; | |
1719 | ||
1720 | static void work_fn(struct work_struct *w) | |
1721 | { | |
1722 | cleanup_old_buffers(); | |
1723 | ||
1724 | queue_delayed_work(dm_bufio_wq, &dm_bufio_work, | |
1725 | DM_BUFIO_WORK_TIMER_SECS * HZ); | |
1726 | } | |
1727 | ||
1728 | /*---------------------------------------------------------------- | |
1729 | * Module setup | |
1730 | *--------------------------------------------------------------*/ | |
1731 | ||
1732 | /* | |
1733 | * This is called only once for the whole dm_bufio module. | |
1734 | * It initializes memory limit. | |
1735 | */ | |
1736 | static int __init dm_bufio_init(void) | |
1737 | { | |
1738 | __u64 mem; | |
1739 | ||
4cb57ab4 MP |
1740 | dm_bufio_allocated_kmem_cache = 0; |
1741 | dm_bufio_allocated_get_free_pages = 0; | |
1742 | dm_bufio_allocated_vmalloc = 0; | |
1743 | dm_bufio_current_allocated = 0; | |
1744 | ||
95d402f0 MP |
1745 | memset(&dm_bufio_caches, 0, sizeof dm_bufio_caches); |
1746 | memset(&dm_bufio_cache_names, 0, sizeof dm_bufio_cache_names); | |
1747 | ||
1748 | mem = (__u64)((totalram_pages - totalhigh_pages) * | |
1749 | DM_BUFIO_MEMORY_PERCENT / 100) << PAGE_SHIFT; | |
1750 | ||
1751 | if (mem > ULONG_MAX) | |
1752 | mem = ULONG_MAX; | |
1753 | ||
1754 | #ifdef CONFIG_MMU | |
1755 | /* | |
1756 | * Get the size of vmalloc space the same way as VMALLOC_TOTAL | |
1757 | * in fs/proc/internal.h | |
1758 | */ | |
1759 | if (mem > (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100) | |
1760 | mem = (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100; | |
1761 | #endif | |
1762 | ||
1763 | dm_bufio_default_cache_size = mem; | |
1764 | ||
1765 | mutex_lock(&dm_bufio_clients_lock); | |
1766 | __cache_size_refresh(); | |
1767 | mutex_unlock(&dm_bufio_clients_lock); | |
1768 | ||
1769 | dm_bufio_wq = create_singlethread_workqueue("dm_bufio_cache"); | |
1770 | if (!dm_bufio_wq) | |
1771 | return -ENOMEM; | |
1772 | ||
1773 | INIT_DELAYED_WORK(&dm_bufio_work, work_fn); | |
1774 | queue_delayed_work(dm_bufio_wq, &dm_bufio_work, | |
1775 | DM_BUFIO_WORK_TIMER_SECS * HZ); | |
1776 | ||
1777 | return 0; | |
1778 | } | |
1779 | ||
1780 | /* | |
1781 | * This is called once when unloading the dm_bufio module. | |
1782 | */ | |
1783 | static void __exit dm_bufio_exit(void) | |
1784 | { | |
1785 | int bug = 0; | |
1786 | int i; | |
1787 | ||
1788 | cancel_delayed_work_sync(&dm_bufio_work); | |
1789 | destroy_workqueue(dm_bufio_wq); | |
1790 | ||
1791 | for (i = 0; i < ARRAY_SIZE(dm_bufio_caches); i++) { | |
1792 | struct kmem_cache *kc = dm_bufio_caches[i]; | |
1793 | ||
1794 | if (kc) | |
1795 | kmem_cache_destroy(kc); | |
1796 | } | |
1797 | ||
1798 | for (i = 0; i < ARRAY_SIZE(dm_bufio_cache_names); i++) | |
1799 | kfree(dm_bufio_cache_names[i]); | |
1800 | ||
1801 | if (dm_bufio_client_count) { | |
1802 | DMCRIT("%s: dm_bufio_client_count leaked: %d", | |
1803 | __func__, dm_bufio_client_count); | |
1804 | bug = 1; | |
1805 | } | |
1806 | ||
1807 | if (dm_bufio_current_allocated) { | |
1808 | DMCRIT("%s: dm_bufio_current_allocated leaked: %lu", | |
1809 | __func__, dm_bufio_current_allocated); | |
1810 | bug = 1; | |
1811 | } | |
1812 | ||
1813 | if (dm_bufio_allocated_get_free_pages) { | |
1814 | DMCRIT("%s: dm_bufio_allocated_get_free_pages leaked: %lu", | |
1815 | __func__, dm_bufio_allocated_get_free_pages); | |
1816 | bug = 1; | |
1817 | } | |
1818 | ||
1819 | if (dm_bufio_allocated_vmalloc) { | |
1820 | DMCRIT("%s: dm_bufio_vmalloc leaked: %lu", | |
1821 | __func__, dm_bufio_allocated_vmalloc); | |
1822 | bug = 1; | |
1823 | } | |
1824 | ||
1825 | if (bug) | |
1826 | BUG(); | |
1827 | } | |
1828 | ||
1829 | module_init(dm_bufio_init) | |
1830 | module_exit(dm_bufio_exit) | |
1831 | ||
1832 | module_param_named(max_cache_size_bytes, dm_bufio_cache_size, ulong, S_IRUGO | S_IWUSR); | |
1833 | MODULE_PARM_DESC(max_cache_size_bytes, "Size of metadata cache"); | |
1834 | ||
1835 | module_param_named(max_age_seconds, dm_bufio_max_age, uint, S_IRUGO | S_IWUSR); | |
1836 | MODULE_PARM_DESC(max_age_seconds, "Max age of a buffer in seconds"); | |
1837 | ||
1838 | module_param_named(peak_allocated_bytes, dm_bufio_peak_allocated, ulong, S_IRUGO | S_IWUSR); | |
1839 | MODULE_PARM_DESC(peak_allocated_bytes, "Tracks the maximum allocated memory"); | |
1840 | ||
1841 | module_param_named(allocated_kmem_cache_bytes, dm_bufio_allocated_kmem_cache, ulong, S_IRUGO); | |
1842 | MODULE_PARM_DESC(allocated_kmem_cache_bytes, "Memory allocated with kmem_cache_alloc"); | |
1843 | ||
1844 | module_param_named(allocated_get_free_pages_bytes, dm_bufio_allocated_get_free_pages, ulong, S_IRUGO); | |
1845 | MODULE_PARM_DESC(allocated_get_free_pages_bytes, "Memory allocated with get_free_pages"); | |
1846 | ||
1847 | module_param_named(allocated_vmalloc_bytes, dm_bufio_allocated_vmalloc, ulong, S_IRUGO); | |
1848 | MODULE_PARM_DESC(allocated_vmalloc_bytes, "Memory allocated with vmalloc"); | |
1849 | ||
1850 | module_param_named(current_allocated_bytes, dm_bufio_current_allocated, ulong, S_IRUGO); | |
1851 | MODULE_PARM_DESC(current_allocated_bytes, "Memory currently used by the cache"); | |
1852 | ||
1853 | MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>"); | |
1854 | MODULE_DESCRIPTION(DM_NAME " buffered I/O library"); | |
1855 | MODULE_LICENSE("GPL"); |