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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> | |
f495339c | 14 | #include <linux/jiffies.h> |
95d402f0 | 15 | #include <linux/vmalloc.h> |
95d402f0 | 16 | #include <linux/shrinker.h> |
6f66263f | 17 | #include <linux/module.h> |
4e420c45 | 18 | #include <linux/rbtree.h> |
86bad0c7 | 19 | #include <linux/stacktrace.h> |
95d402f0 MP |
20 | |
21 | #define DM_MSG_PREFIX "bufio" | |
22 | ||
23 | /* | |
24 | * Memory management policy: | |
25 | * Limit the number of buffers to DM_BUFIO_MEMORY_PERCENT of main memory | |
26 | * or DM_BUFIO_VMALLOC_PERCENT of vmalloc memory (whichever is lower). | |
27 | * Always allocate at least DM_BUFIO_MIN_BUFFERS buffers. | |
28 | * Start background writeback when there are DM_BUFIO_WRITEBACK_PERCENT | |
29 | * dirty buffers. | |
30 | */ | |
31 | #define DM_BUFIO_MIN_BUFFERS 8 | |
32 | ||
33 | #define DM_BUFIO_MEMORY_PERCENT 2 | |
34 | #define DM_BUFIO_VMALLOC_PERCENT 25 | |
35 | #define DM_BUFIO_WRITEBACK_PERCENT 75 | |
36 | ||
37 | /* | |
38 | * Check buffer ages in this interval (seconds) | |
39 | */ | |
33096a78 | 40 | #define DM_BUFIO_WORK_TIMER_SECS 30 |
95d402f0 MP |
41 | |
42 | /* | |
43 | * Free buffers when they are older than this (seconds) | |
44 | */ | |
33096a78 | 45 | #define DM_BUFIO_DEFAULT_AGE_SECS 300 |
95d402f0 MP |
46 | |
47 | /* | |
33096a78 | 48 | * The nr of bytes of cached data to keep around. |
95d402f0 | 49 | */ |
33096a78 | 50 | #define DM_BUFIO_DEFAULT_RETAIN_BYTES (256 * 1024) |
95d402f0 MP |
51 | |
52 | /* | |
95d402f0 MP |
53 | * The number of bvec entries that are embedded directly in the buffer. |
54 | * If the chunk size is larger, dm-io is used to do the io. | |
95d402f0 | 55 | */ |
95d402f0 | 56 | #define DM_BUFIO_INLINE_VECS 16 |
95d402f0 MP |
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 | ||
4e420c45 | 109 | struct rb_root buffer_tree; |
95d402f0 MP |
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 { | |
4e420c45 | 138 | struct rb_node node; |
95d402f0 MP |
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]; | |
86bad0c7 MP |
153 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
154 | #define MAX_STACK 10 | |
155 | struct stack_trace stack_trace; | |
156 | unsigned long stack_entries[MAX_STACK]; | |
157 | #endif | |
95d402f0 MP |
158 | }; |
159 | ||
160 | /*----------------------------------------------------------------*/ | |
161 | ||
162 | static struct kmem_cache *dm_bufio_caches[PAGE_SHIFT - SECTOR_SHIFT]; | |
163 | static char *dm_bufio_cache_names[PAGE_SHIFT - SECTOR_SHIFT]; | |
164 | ||
165 | static inline int dm_bufio_cache_index(struct dm_bufio_client *c) | |
166 | { | |
167 | unsigned ret = c->blocks_per_page_bits - 1; | |
168 | ||
169 | BUG_ON(ret >= ARRAY_SIZE(dm_bufio_caches)); | |
170 | ||
171 | return ret; | |
172 | } | |
173 | ||
174 | #define DM_BUFIO_CACHE(c) (dm_bufio_caches[dm_bufio_cache_index(c)]) | |
175 | #define DM_BUFIO_CACHE_NAME(c) (dm_bufio_cache_names[dm_bufio_cache_index(c)]) | |
176 | ||
177 | #define dm_bufio_in_request() (!!current->bio_list) | |
178 | ||
179 | static void dm_bufio_lock(struct dm_bufio_client *c) | |
180 | { | |
181 | mutex_lock_nested(&c->lock, dm_bufio_in_request()); | |
182 | } | |
183 | ||
184 | static int dm_bufio_trylock(struct dm_bufio_client *c) | |
185 | { | |
186 | return mutex_trylock(&c->lock); | |
187 | } | |
188 | ||
189 | static void dm_bufio_unlock(struct dm_bufio_client *c) | |
190 | { | |
191 | mutex_unlock(&c->lock); | |
192 | } | |
193 | ||
95d402f0 MP |
194 | /*----------------------------------------------------------------*/ |
195 | ||
196 | /* | |
197 | * Default cache size: available memory divided by the ratio. | |
198 | */ | |
199 | static unsigned long dm_bufio_default_cache_size; | |
200 | ||
201 | /* | |
202 | * Total cache size set by the user. | |
203 | */ | |
204 | static unsigned long dm_bufio_cache_size; | |
205 | ||
206 | /* | |
207 | * A copy of dm_bufio_cache_size because dm_bufio_cache_size can change | |
208 | * at any time. If it disagrees, the user has changed cache size. | |
209 | */ | |
210 | static unsigned long dm_bufio_cache_size_latch; | |
211 | ||
212 | static DEFINE_SPINLOCK(param_spinlock); | |
213 | ||
214 | /* | |
215 | * Buffers are freed after this timeout | |
216 | */ | |
217 | static unsigned dm_bufio_max_age = DM_BUFIO_DEFAULT_AGE_SECS; | |
33096a78 | 218 | static unsigned dm_bufio_retain_bytes = DM_BUFIO_DEFAULT_RETAIN_BYTES; |
95d402f0 MP |
219 | |
220 | static unsigned long dm_bufio_peak_allocated; | |
221 | static unsigned long dm_bufio_allocated_kmem_cache; | |
222 | static unsigned long dm_bufio_allocated_get_free_pages; | |
223 | static unsigned long dm_bufio_allocated_vmalloc; | |
224 | static unsigned long dm_bufio_current_allocated; | |
225 | ||
226 | /*----------------------------------------------------------------*/ | |
227 | ||
228 | /* | |
229 | * Per-client cache: dm_bufio_cache_size / dm_bufio_client_count | |
230 | */ | |
231 | static unsigned long dm_bufio_cache_size_per_client; | |
232 | ||
233 | /* | |
234 | * The current number of clients. | |
235 | */ | |
236 | static int dm_bufio_client_count; | |
237 | ||
238 | /* | |
239 | * The list of all clients. | |
240 | */ | |
241 | static LIST_HEAD(dm_bufio_all_clients); | |
242 | ||
243 | /* | |
244 | * This mutex protects dm_bufio_cache_size_latch, | |
245 | * dm_bufio_cache_size_per_client and dm_bufio_client_count | |
246 | */ | |
247 | static DEFINE_MUTEX(dm_bufio_clients_lock); | |
248 | ||
86bad0c7 MP |
249 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
250 | static void buffer_record_stack(struct dm_buffer *b) | |
251 | { | |
252 | b->stack_trace.nr_entries = 0; | |
253 | b->stack_trace.max_entries = MAX_STACK; | |
254 | b->stack_trace.entries = b->stack_entries; | |
255 | b->stack_trace.skip = 2; | |
256 | save_stack_trace(&b->stack_trace); | |
257 | } | |
258 | #endif | |
259 | ||
4e420c45 JT |
260 | /*---------------------------------------------------------------- |
261 | * A red/black tree acts as an index for all the buffers. | |
262 | *--------------------------------------------------------------*/ | |
263 | static struct dm_buffer *__find(struct dm_bufio_client *c, sector_t block) | |
264 | { | |
265 | struct rb_node *n = c->buffer_tree.rb_node; | |
266 | struct dm_buffer *b; | |
267 | ||
268 | while (n) { | |
269 | b = container_of(n, struct dm_buffer, node); | |
270 | ||
271 | if (b->block == block) | |
272 | return b; | |
273 | ||
274 | n = (b->block < block) ? n->rb_left : n->rb_right; | |
275 | } | |
276 | ||
277 | return NULL; | |
278 | } | |
279 | ||
280 | static void __insert(struct dm_bufio_client *c, struct dm_buffer *b) | |
281 | { | |
282 | struct rb_node **new = &c->buffer_tree.rb_node, *parent = NULL; | |
283 | struct dm_buffer *found; | |
284 | ||
285 | while (*new) { | |
286 | found = container_of(*new, struct dm_buffer, node); | |
287 | ||
288 | if (found->block == b->block) { | |
289 | BUG_ON(found != b); | |
290 | return; | |
291 | } | |
292 | ||
293 | parent = *new; | |
294 | new = (found->block < b->block) ? | |
295 | &((*new)->rb_left) : &((*new)->rb_right); | |
296 | } | |
297 | ||
298 | rb_link_node(&b->node, parent, new); | |
299 | rb_insert_color(&b->node, &c->buffer_tree); | |
300 | } | |
301 | ||
302 | static void __remove(struct dm_bufio_client *c, struct dm_buffer *b) | |
303 | { | |
304 | rb_erase(&b->node, &c->buffer_tree); | |
305 | } | |
306 | ||
95d402f0 MP |
307 | /*----------------------------------------------------------------*/ |
308 | ||
309 | static void adjust_total_allocated(enum data_mode data_mode, long diff) | |
310 | { | |
311 | static unsigned long * const class_ptr[DATA_MODE_LIMIT] = { | |
312 | &dm_bufio_allocated_kmem_cache, | |
313 | &dm_bufio_allocated_get_free_pages, | |
314 | &dm_bufio_allocated_vmalloc, | |
315 | }; | |
316 | ||
317 | spin_lock(¶m_spinlock); | |
318 | ||
319 | *class_ptr[data_mode] += diff; | |
320 | ||
321 | dm_bufio_current_allocated += diff; | |
322 | ||
323 | if (dm_bufio_current_allocated > dm_bufio_peak_allocated) | |
324 | dm_bufio_peak_allocated = dm_bufio_current_allocated; | |
325 | ||
326 | spin_unlock(¶m_spinlock); | |
327 | } | |
328 | ||
329 | /* | |
330 | * Change the number of clients and recalculate per-client limit. | |
331 | */ | |
332 | static void __cache_size_refresh(void) | |
333 | { | |
334 | BUG_ON(!mutex_is_locked(&dm_bufio_clients_lock)); | |
335 | BUG_ON(dm_bufio_client_count < 0); | |
336 | ||
fe5fe906 | 337 | dm_bufio_cache_size_latch = ACCESS_ONCE(dm_bufio_cache_size); |
95d402f0 MP |
338 | |
339 | /* | |
340 | * Use default if set to 0 and report the actual cache size used. | |
341 | */ | |
342 | if (!dm_bufio_cache_size_latch) { | |
343 | (void)cmpxchg(&dm_bufio_cache_size, 0, | |
344 | dm_bufio_default_cache_size); | |
345 | dm_bufio_cache_size_latch = dm_bufio_default_cache_size; | |
346 | } | |
347 | ||
348 | dm_bufio_cache_size_per_client = dm_bufio_cache_size_latch / | |
349 | (dm_bufio_client_count ? : 1); | |
350 | } | |
351 | ||
352 | /* | |
353 | * Allocating buffer data. | |
354 | * | |
355 | * Small buffers are allocated with kmem_cache, to use space optimally. | |
356 | * | |
357 | * For large buffers, we choose between get_free_pages and vmalloc. | |
358 | * Each has advantages and disadvantages. | |
359 | * | |
360 | * __get_free_pages can randomly fail if the memory is fragmented. | |
361 | * __vmalloc won't randomly fail, but vmalloc space is limited (it may be | |
362 | * as low as 128M) so using it for caching is not appropriate. | |
363 | * | |
364 | * If the allocation may fail we use __get_free_pages. Memory fragmentation | |
365 | * won't have a fatal effect here, but it just causes flushes of some other | |
366 | * buffers and more I/O will be performed. Don't use __get_free_pages if it | |
367 | * always fails (i.e. order >= MAX_ORDER). | |
368 | * | |
369 | * If the allocation shouldn't fail we use __vmalloc. This is only for the | |
370 | * initial reserve allocation, so there's no risk of wasting all vmalloc | |
371 | * space. | |
372 | */ | |
373 | static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask, | |
374 | enum data_mode *data_mode) | |
375 | { | |
502624bd MP |
376 | unsigned noio_flag; |
377 | void *ptr; | |
378 | ||
95d402f0 MP |
379 | if (c->block_size <= DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT) { |
380 | *data_mode = DATA_MODE_SLAB; | |
381 | return kmem_cache_alloc(DM_BUFIO_CACHE(c), gfp_mask); | |
382 | } | |
383 | ||
384 | if (c->block_size <= DM_BUFIO_BLOCK_SIZE_GFP_LIMIT && | |
385 | gfp_mask & __GFP_NORETRY) { | |
386 | *data_mode = DATA_MODE_GET_FREE_PAGES; | |
387 | return (void *)__get_free_pages(gfp_mask, | |
388 | c->pages_per_block_bits); | |
389 | } | |
390 | ||
391 | *data_mode = DATA_MODE_VMALLOC; | |
502624bd MP |
392 | |
393 | /* | |
394 | * __vmalloc allocates the data pages and auxiliary structures with | |
395 | * gfp_flags that were specified, but pagetables are always allocated | |
396 | * with GFP_KERNEL, no matter what was specified as gfp_mask. | |
397 | * | |
398 | * Consequently, we must set per-process flag PF_MEMALLOC_NOIO so that | |
399 | * all allocations done by this process (including pagetables) are done | |
400 | * as if GFP_NOIO was specified. | |
401 | */ | |
402 | ||
403 | if (gfp_mask & __GFP_NORETRY) | |
404 | noio_flag = memalloc_noio_save(); | |
405 | ||
220cd058 | 406 | ptr = __vmalloc(c->block_size, gfp_mask | __GFP_HIGHMEM, PAGE_KERNEL); |
502624bd MP |
407 | |
408 | if (gfp_mask & __GFP_NORETRY) | |
409 | memalloc_noio_restore(noio_flag); | |
410 | ||
411 | return ptr; | |
95d402f0 MP |
412 | } |
413 | ||
414 | /* | |
415 | * Free buffer's data. | |
416 | */ | |
417 | static void free_buffer_data(struct dm_bufio_client *c, | |
418 | void *data, enum data_mode data_mode) | |
419 | { | |
420 | switch (data_mode) { | |
421 | case DATA_MODE_SLAB: | |
422 | kmem_cache_free(DM_BUFIO_CACHE(c), data); | |
423 | break; | |
424 | ||
425 | case DATA_MODE_GET_FREE_PAGES: | |
426 | free_pages((unsigned long)data, c->pages_per_block_bits); | |
427 | break; | |
428 | ||
429 | case DATA_MODE_VMALLOC: | |
430 | vfree(data); | |
431 | break; | |
432 | ||
433 | default: | |
434 | DMCRIT("dm_bufio_free_buffer_data: bad data mode: %d", | |
435 | data_mode); | |
436 | BUG(); | |
437 | } | |
438 | } | |
439 | ||
440 | /* | |
441 | * Allocate buffer and its data. | |
442 | */ | |
443 | static struct dm_buffer *alloc_buffer(struct dm_bufio_client *c, gfp_t gfp_mask) | |
444 | { | |
445 | struct dm_buffer *b = kmalloc(sizeof(struct dm_buffer) + c->aux_size, | |
446 | gfp_mask); | |
447 | ||
448 | if (!b) | |
449 | return NULL; | |
450 | ||
451 | b->c = c; | |
452 | ||
453 | b->data = alloc_buffer_data(c, gfp_mask, &b->data_mode); | |
454 | if (!b->data) { | |
455 | kfree(b); | |
456 | return NULL; | |
457 | } | |
458 | ||
459 | adjust_total_allocated(b->data_mode, (long)c->block_size); | |
460 | ||
86bad0c7 MP |
461 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
462 | memset(&b->stack_trace, 0, sizeof(b->stack_trace)); | |
463 | #endif | |
95d402f0 MP |
464 | return b; |
465 | } | |
466 | ||
467 | /* | |
468 | * Free buffer and its data. | |
469 | */ | |
470 | static void free_buffer(struct dm_buffer *b) | |
471 | { | |
472 | struct dm_bufio_client *c = b->c; | |
473 | ||
474 | adjust_total_allocated(b->data_mode, -(long)c->block_size); | |
475 | ||
476 | free_buffer_data(c, b->data, b->data_mode); | |
477 | kfree(b); | |
478 | } | |
479 | ||
480 | /* | |
481 | * Link buffer to the hash list and clean or dirty queue. | |
482 | */ | |
483 | static void __link_buffer(struct dm_buffer *b, sector_t block, int dirty) | |
484 | { | |
485 | struct dm_bufio_client *c = b->c; | |
486 | ||
487 | c->n_buffers[dirty]++; | |
488 | b->block = block; | |
489 | b->list_mode = dirty; | |
490 | list_add(&b->lru_list, &c->lru[dirty]); | |
4e420c45 | 491 | __insert(b->c, b); |
95d402f0 MP |
492 | b->last_accessed = jiffies; |
493 | } | |
494 | ||
495 | /* | |
496 | * Unlink buffer from the hash list and dirty or clean queue. | |
497 | */ | |
498 | static void __unlink_buffer(struct dm_buffer *b) | |
499 | { | |
500 | struct dm_bufio_client *c = b->c; | |
501 | ||
502 | BUG_ON(!c->n_buffers[b->list_mode]); | |
503 | ||
504 | c->n_buffers[b->list_mode]--; | |
4e420c45 | 505 | __remove(b->c, b); |
95d402f0 MP |
506 | list_del(&b->lru_list); |
507 | } | |
508 | ||
509 | /* | |
510 | * Place the buffer to the head of dirty or clean LRU queue. | |
511 | */ | |
512 | static void __relink_lru(struct dm_buffer *b, int dirty) | |
513 | { | |
514 | struct dm_bufio_client *c = b->c; | |
515 | ||
516 | BUG_ON(!c->n_buffers[b->list_mode]); | |
517 | ||
518 | c->n_buffers[b->list_mode]--; | |
519 | c->n_buffers[dirty]++; | |
520 | b->list_mode = dirty; | |
54499afb | 521 | list_move(&b->lru_list, &c->lru[dirty]); |
eb76faf5 | 522 | b->last_accessed = jiffies; |
95d402f0 MP |
523 | } |
524 | ||
525 | /*---------------------------------------------------------------- | |
526 | * Submit I/O on the buffer. | |
527 | * | |
528 | * Bio interface is faster but it has some problems: | |
529 | * the vector list is limited (increasing this limit increases | |
530 | * memory-consumption per buffer, so it is not viable); | |
531 | * | |
532 | * the memory must be direct-mapped, not vmalloced; | |
533 | * | |
534 | * the I/O driver can reject requests spuriously if it thinks that | |
535 | * the requests are too big for the device or if they cross a | |
536 | * controller-defined memory boundary. | |
537 | * | |
538 | * If the buffer is small enough (up to DM_BUFIO_INLINE_VECS pages) and | |
539 | * it is not vmalloced, try using the bio interface. | |
540 | * | |
541 | * If the buffer is big, if it is vmalloced or if the underlying device | |
542 | * rejects the bio because it is too large, use dm-io layer to do the I/O. | |
543 | * The dm-io layer splits the I/O into multiple requests, avoiding the above | |
544 | * shortcomings. | |
545 | *--------------------------------------------------------------*/ | |
546 | ||
547 | /* | |
548 | * dm-io completion routine. It just calls b->bio.bi_end_io, pretending | |
549 | * that the request was handled directly with bio interface. | |
550 | */ | |
551 | static void dmio_complete(unsigned long error, void *context) | |
552 | { | |
553 | struct dm_buffer *b = context; | |
554 | ||
4246a0b6 CH |
555 | b->bio.bi_error = error ? -EIO : 0; |
556 | b->bio.bi_end_io(&b->bio); | |
95d402f0 MP |
557 | } |
558 | ||
559 | static void use_dmio(struct dm_buffer *b, int rw, sector_t block, | |
560 | bio_end_io_t *end_io) | |
561 | { | |
562 | int r; | |
563 | struct dm_io_request io_req = { | |
e6047149 MC |
564 | .bi_op = rw, |
565 | .bi_op_flags = 0, | |
95d402f0 MP |
566 | .notify.fn = dmio_complete, |
567 | .notify.context = b, | |
568 | .client = b->c->dm_io, | |
569 | }; | |
570 | struct dm_io_region region = { | |
571 | .bdev = b->c->bdev, | |
572 | .sector = block << b->c->sectors_per_block_bits, | |
573 | .count = b->c->block_size >> SECTOR_SHIFT, | |
574 | }; | |
575 | ||
576 | if (b->data_mode != DATA_MODE_VMALLOC) { | |
577 | io_req.mem.type = DM_IO_KMEM; | |
578 | io_req.mem.ptr.addr = b->data; | |
579 | } else { | |
580 | io_req.mem.type = DM_IO_VMA; | |
581 | io_req.mem.ptr.vma = b->data; | |
582 | } | |
583 | ||
584 | b->bio.bi_end_io = end_io; | |
585 | ||
586 | r = dm_io(&io_req, 1, ®ion, NULL); | |
4246a0b6 CH |
587 | if (r) { |
588 | b->bio.bi_error = r; | |
589 | end_io(&b->bio); | |
590 | } | |
95d402f0 MP |
591 | } |
592 | ||
4246a0b6 | 593 | static void inline_endio(struct bio *bio) |
445559cd DW |
594 | { |
595 | bio_end_io_t *end_fn = bio->bi_private; | |
4246a0b6 | 596 | int error = bio->bi_error; |
445559cd DW |
597 | |
598 | /* | |
599 | * Reset the bio to free any attached resources | |
600 | * (e.g. bio integrity profiles). | |
601 | */ | |
602 | bio_reset(bio); | |
603 | ||
4246a0b6 CH |
604 | bio->bi_error = error; |
605 | end_fn(bio); | |
445559cd DW |
606 | } |
607 | ||
95d402f0 MP |
608 | static void use_inline_bio(struct dm_buffer *b, int rw, sector_t block, |
609 | bio_end_io_t *end_io) | |
610 | { | |
611 | char *ptr; | |
612 | int len; | |
613 | ||
3a83f467 | 614 | bio_init(&b->bio, b->bio_vec, DM_BUFIO_INLINE_VECS); |
4f024f37 | 615 | b->bio.bi_iter.bi_sector = block << b->c->sectors_per_block_bits; |
95d402f0 | 616 | b->bio.bi_bdev = b->c->bdev; |
445559cd DW |
617 | b->bio.bi_end_io = inline_endio; |
618 | /* | |
619 | * Use of .bi_private isn't a problem here because | |
620 | * the dm_buffer's inline bio is local to bufio. | |
621 | */ | |
622 | b->bio.bi_private = end_io; | |
e6047149 | 623 | bio_set_op_attrs(&b->bio, rw, 0); |
95d402f0 MP |
624 | |
625 | /* | |
626 | * We assume that if len >= PAGE_SIZE ptr is page-aligned. | |
627 | * If len < PAGE_SIZE the buffer doesn't cross page boundary. | |
628 | */ | |
629 | ptr = b->data; | |
630 | len = b->c->block_size; | |
631 | ||
632 | if (len >= PAGE_SIZE) | |
633 | BUG_ON((unsigned long)ptr & (PAGE_SIZE - 1)); | |
634 | else | |
635 | BUG_ON((unsigned long)ptr & (len - 1)); | |
636 | ||
637 | do { | |
638 | if (!bio_add_page(&b->bio, virt_to_page(ptr), | |
639 | len < PAGE_SIZE ? len : PAGE_SIZE, | |
756d097b | 640 | offset_in_page(ptr))) { |
95d402f0 MP |
641 | BUG_ON(b->c->block_size <= PAGE_SIZE); |
642 | use_dmio(b, rw, block, end_io); | |
643 | return; | |
644 | } | |
645 | ||
646 | len -= PAGE_SIZE; | |
647 | ptr += PAGE_SIZE; | |
648 | } while (len > 0); | |
649 | ||
4e49ea4a | 650 | submit_bio(&b->bio); |
95d402f0 MP |
651 | } |
652 | ||
653 | static void submit_io(struct dm_buffer *b, int rw, sector_t block, | |
654 | bio_end_io_t *end_io) | |
655 | { | |
656 | if (rw == WRITE && b->c->write_callback) | |
657 | b->c->write_callback(b); | |
658 | ||
659 | if (b->c->block_size <= DM_BUFIO_INLINE_VECS * PAGE_SIZE && | |
660 | b->data_mode != DATA_MODE_VMALLOC) | |
661 | use_inline_bio(b, rw, block, end_io); | |
662 | else | |
663 | use_dmio(b, rw, block, end_io); | |
664 | } | |
665 | ||
666 | /*---------------------------------------------------------------- | |
667 | * Writing dirty buffers | |
668 | *--------------------------------------------------------------*/ | |
669 | ||
670 | /* | |
671 | * The endio routine for write. | |
672 | * | |
673 | * Set the error, clear B_WRITING bit and wake anyone who was waiting on | |
674 | * it. | |
675 | */ | |
4246a0b6 | 676 | static void write_endio(struct bio *bio) |
95d402f0 MP |
677 | { |
678 | struct dm_buffer *b = container_of(bio, struct dm_buffer, bio); | |
679 | ||
4246a0b6 CH |
680 | b->write_error = bio->bi_error; |
681 | if (unlikely(bio->bi_error)) { | |
95d402f0 | 682 | struct dm_bufio_client *c = b->c; |
4246a0b6 | 683 | int error = bio->bi_error; |
95d402f0 MP |
684 | (void)cmpxchg(&c->async_write_error, 0, error); |
685 | } | |
686 | ||
687 | BUG_ON(!test_bit(B_WRITING, &b->state)); | |
688 | ||
4e857c58 | 689 | smp_mb__before_atomic(); |
95d402f0 | 690 | clear_bit(B_WRITING, &b->state); |
4e857c58 | 691 | smp_mb__after_atomic(); |
95d402f0 MP |
692 | |
693 | wake_up_bit(&b->state, B_WRITING); | |
694 | } | |
695 | ||
95d402f0 MP |
696 | /* |
697 | * Initiate a write on a dirty buffer, but don't wait for it. | |
698 | * | |
699 | * - If the buffer is not dirty, exit. | |
700 | * - If there some previous write going on, wait for it to finish (we can't | |
701 | * have two writes on the same buffer simultaneously). | |
702 | * - Submit our write and don't wait on it. We set B_WRITING indicating | |
703 | * that there is a write in progress. | |
704 | */ | |
2480945c MP |
705 | static void __write_dirty_buffer(struct dm_buffer *b, |
706 | struct list_head *write_list) | |
95d402f0 MP |
707 | { |
708 | if (!test_bit(B_DIRTY, &b->state)) | |
709 | return; | |
710 | ||
711 | clear_bit(B_DIRTY, &b->state); | |
74316201 | 712 | wait_on_bit_lock_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE); |
95d402f0 | 713 | |
2480945c MP |
714 | if (!write_list) |
715 | submit_io(b, WRITE, b->block, write_endio); | |
716 | else | |
717 | list_add_tail(&b->write_list, write_list); | |
718 | } | |
719 | ||
720 | static void __flush_write_list(struct list_head *write_list) | |
721 | { | |
722 | struct blk_plug plug; | |
723 | blk_start_plug(&plug); | |
724 | while (!list_empty(write_list)) { | |
725 | struct dm_buffer *b = | |
726 | list_entry(write_list->next, struct dm_buffer, write_list); | |
727 | list_del(&b->write_list); | |
728 | submit_io(b, WRITE, b->block, write_endio); | |
7cd32674 | 729 | cond_resched(); |
2480945c MP |
730 | } |
731 | blk_finish_plug(&plug); | |
95d402f0 MP |
732 | } |
733 | ||
734 | /* | |
735 | * Wait until any activity on the buffer finishes. Possibly write the | |
736 | * buffer if it is dirty. When this function finishes, there is no I/O | |
737 | * running on the buffer and the buffer is not dirty. | |
738 | */ | |
739 | static void __make_buffer_clean(struct dm_buffer *b) | |
740 | { | |
741 | BUG_ON(b->hold_count); | |
742 | ||
743 | if (!b->state) /* fast case */ | |
744 | return; | |
745 | ||
74316201 | 746 | wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE); |
2480945c | 747 | __write_dirty_buffer(b, NULL); |
74316201 | 748 | wait_on_bit_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE); |
95d402f0 MP |
749 | } |
750 | ||
751 | /* | |
752 | * Find some buffer that is not held by anybody, clean it, unlink it and | |
753 | * return it. | |
754 | */ | |
755 | static struct dm_buffer *__get_unclaimed_buffer(struct dm_bufio_client *c) | |
756 | { | |
757 | struct dm_buffer *b; | |
758 | ||
759 | list_for_each_entry_reverse(b, &c->lru[LIST_CLEAN], lru_list) { | |
760 | BUG_ON(test_bit(B_WRITING, &b->state)); | |
761 | BUG_ON(test_bit(B_DIRTY, &b->state)); | |
762 | ||
763 | if (!b->hold_count) { | |
764 | __make_buffer_clean(b); | |
765 | __unlink_buffer(b); | |
766 | return b; | |
767 | } | |
7cd32674 | 768 | cond_resched(); |
95d402f0 MP |
769 | } |
770 | ||
771 | list_for_each_entry_reverse(b, &c->lru[LIST_DIRTY], lru_list) { | |
772 | BUG_ON(test_bit(B_READING, &b->state)); | |
773 | ||
774 | if (!b->hold_count) { | |
775 | __make_buffer_clean(b); | |
776 | __unlink_buffer(b); | |
777 | return b; | |
778 | } | |
7cd32674 | 779 | cond_resched(); |
95d402f0 MP |
780 | } |
781 | ||
782 | return NULL; | |
783 | } | |
784 | ||
785 | /* | |
786 | * Wait until some other threads free some buffer or release hold count on | |
787 | * some buffer. | |
788 | * | |
789 | * This function is entered with c->lock held, drops it and regains it | |
790 | * before exiting. | |
791 | */ | |
792 | static void __wait_for_free_buffer(struct dm_bufio_client *c) | |
793 | { | |
794 | DECLARE_WAITQUEUE(wait, current); | |
795 | ||
796 | add_wait_queue(&c->free_buffer_wait, &wait); | |
797 | set_task_state(current, TASK_UNINTERRUPTIBLE); | |
798 | dm_bufio_unlock(c); | |
799 | ||
800 | io_schedule(); | |
801 | ||
95d402f0 MP |
802 | remove_wait_queue(&c->free_buffer_wait, &wait); |
803 | ||
804 | dm_bufio_lock(c); | |
805 | } | |
806 | ||
a66cc28f MP |
807 | enum new_flag { |
808 | NF_FRESH = 0, | |
809 | NF_READ = 1, | |
810 | NF_GET = 2, | |
811 | NF_PREFETCH = 3 | |
812 | }; | |
813 | ||
95d402f0 MP |
814 | /* |
815 | * Allocate a new buffer. If the allocation is not possible, wait until | |
816 | * some other thread frees a buffer. | |
817 | * | |
818 | * May drop the lock and regain it. | |
819 | */ | |
a66cc28f | 820 | static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client *c, enum new_flag nf) |
95d402f0 MP |
821 | { |
822 | struct dm_buffer *b; | |
823 | ||
824 | /* | |
825 | * dm-bufio is resistant to allocation failures (it just keeps | |
826 | * one buffer reserved in cases all the allocations fail). | |
827 | * So set flags to not try too hard: | |
828 | * GFP_NOIO: don't recurse into the I/O layer | |
829 | * __GFP_NORETRY: don't retry and rather return failure | |
830 | * __GFP_NOMEMALLOC: don't use emergency reserves | |
831 | * __GFP_NOWARN: don't print a warning in case of failure | |
832 | * | |
833 | * For debugging, if we set the cache size to 1, no new buffers will | |
834 | * be allocated. | |
835 | */ | |
836 | while (1) { | |
837 | if (dm_bufio_cache_size_latch != 1) { | |
838 | b = alloc_buffer(c, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); | |
839 | if (b) | |
840 | return b; | |
841 | } | |
842 | ||
a66cc28f MP |
843 | if (nf == NF_PREFETCH) |
844 | return NULL; | |
845 | ||
95d402f0 MP |
846 | if (!list_empty(&c->reserved_buffers)) { |
847 | b = list_entry(c->reserved_buffers.next, | |
848 | struct dm_buffer, lru_list); | |
849 | list_del(&b->lru_list); | |
850 | c->need_reserved_buffers++; | |
851 | ||
852 | return b; | |
853 | } | |
854 | ||
855 | b = __get_unclaimed_buffer(c); | |
856 | if (b) | |
857 | return b; | |
858 | ||
859 | __wait_for_free_buffer(c); | |
860 | } | |
861 | } | |
862 | ||
a66cc28f | 863 | static struct dm_buffer *__alloc_buffer_wait(struct dm_bufio_client *c, enum new_flag nf) |
95d402f0 | 864 | { |
a66cc28f MP |
865 | struct dm_buffer *b = __alloc_buffer_wait_no_callback(c, nf); |
866 | ||
867 | if (!b) | |
868 | return NULL; | |
95d402f0 MP |
869 | |
870 | if (c->alloc_callback) | |
871 | c->alloc_callback(b); | |
872 | ||
873 | return b; | |
874 | } | |
875 | ||
876 | /* | |
877 | * Free a buffer and wake other threads waiting for free buffers. | |
878 | */ | |
879 | static void __free_buffer_wake(struct dm_buffer *b) | |
880 | { | |
881 | struct dm_bufio_client *c = b->c; | |
882 | ||
883 | if (!c->need_reserved_buffers) | |
884 | free_buffer(b); | |
885 | else { | |
886 | list_add(&b->lru_list, &c->reserved_buffers); | |
887 | c->need_reserved_buffers--; | |
888 | } | |
889 | ||
890 | wake_up(&c->free_buffer_wait); | |
891 | } | |
892 | ||
2480945c MP |
893 | static void __write_dirty_buffers_async(struct dm_bufio_client *c, int no_wait, |
894 | struct list_head *write_list) | |
95d402f0 MP |
895 | { |
896 | struct dm_buffer *b, *tmp; | |
897 | ||
898 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { | |
899 | BUG_ON(test_bit(B_READING, &b->state)); | |
900 | ||
901 | if (!test_bit(B_DIRTY, &b->state) && | |
902 | !test_bit(B_WRITING, &b->state)) { | |
903 | __relink_lru(b, LIST_CLEAN); | |
904 | continue; | |
905 | } | |
906 | ||
907 | if (no_wait && test_bit(B_WRITING, &b->state)) | |
908 | return; | |
909 | ||
2480945c | 910 | __write_dirty_buffer(b, write_list); |
7cd32674 | 911 | cond_resched(); |
95d402f0 MP |
912 | } |
913 | } | |
914 | ||
915 | /* | |
916 | * Get writeback threshold and buffer limit for a given client. | |
917 | */ | |
918 | static void __get_memory_limit(struct dm_bufio_client *c, | |
919 | unsigned long *threshold_buffers, | |
920 | unsigned long *limit_buffers) | |
921 | { | |
922 | unsigned long buffers; | |
923 | ||
fe5fe906 | 924 | if (ACCESS_ONCE(dm_bufio_cache_size) != dm_bufio_cache_size_latch) { |
95d402f0 MP |
925 | mutex_lock(&dm_bufio_clients_lock); |
926 | __cache_size_refresh(); | |
927 | mutex_unlock(&dm_bufio_clients_lock); | |
928 | } | |
929 | ||
930 | buffers = dm_bufio_cache_size_per_client >> | |
931 | (c->sectors_per_block_bits + SECTOR_SHIFT); | |
932 | ||
55b082e6 MP |
933 | if (buffers < c->minimum_buffers) |
934 | buffers = c->minimum_buffers; | |
95d402f0 MP |
935 | |
936 | *limit_buffers = buffers; | |
937 | *threshold_buffers = buffers * DM_BUFIO_WRITEBACK_PERCENT / 100; | |
938 | } | |
939 | ||
940 | /* | |
941 | * Check if we're over watermark. | |
942 | * If we are over threshold_buffers, start freeing buffers. | |
943 | * If we're over "limit_buffers", block until we get under the limit. | |
944 | */ | |
2480945c MP |
945 | static void __check_watermark(struct dm_bufio_client *c, |
946 | struct list_head *write_list) | |
95d402f0 MP |
947 | { |
948 | unsigned long threshold_buffers, limit_buffers; | |
949 | ||
950 | __get_memory_limit(c, &threshold_buffers, &limit_buffers); | |
951 | ||
952 | while (c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY] > | |
953 | limit_buffers) { | |
954 | ||
955 | struct dm_buffer *b = __get_unclaimed_buffer(c); | |
956 | ||
957 | if (!b) | |
958 | return; | |
959 | ||
960 | __free_buffer_wake(b); | |
7cd32674 | 961 | cond_resched(); |
95d402f0 MP |
962 | } |
963 | ||
964 | if (c->n_buffers[LIST_DIRTY] > threshold_buffers) | |
2480945c | 965 | __write_dirty_buffers_async(c, 1, write_list); |
95d402f0 MP |
966 | } |
967 | ||
95d402f0 MP |
968 | /*---------------------------------------------------------------- |
969 | * Getting a buffer | |
970 | *--------------------------------------------------------------*/ | |
971 | ||
95d402f0 | 972 | static struct dm_buffer *__bufio_new(struct dm_bufio_client *c, sector_t block, |
2480945c MP |
973 | enum new_flag nf, int *need_submit, |
974 | struct list_head *write_list) | |
95d402f0 MP |
975 | { |
976 | struct dm_buffer *b, *new_b = NULL; | |
977 | ||
978 | *need_submit = 0; | |
979 | ||
980 | b = __find(c, block); | |
a66cc28f MP |
981 | if (b) |
982 | goto found_buffer; | |
95d402f0 MP |
983 | |
984 | if (nf == NF_GET) | |
985 | return NULL; | |
986 | ||
a66cc28f MP |
987 | new_b = __alloc_buffer_wait(c, nf); |
988 | if (!new_b) | |
989 | return NULL; | |
95d402f0 MP |
990 | |
991 | /* | |
992 | * We've had a period where the mutex was unlocked, so need to | |
993 | * recheck the hash table. | |
994 | */ | |
995 | b = __find(c, block); | |
996 | if (b) { | |
997 | __free_buffer_wake(new_b); | |
a66cc28f | 998 | goto found_buffer; |
95d402f0 MP |
999 | } |
1000 | ||
2480945c | 1001 | __check_watermark(c, write_list); |
95d402f0 MP |
1002 | |
1003 | b = new_b; | |
1004 | b->hold_count = 1; | |
1005 | b->read_error = 0; | |
1006 | b->write_error = 0; | |
1007 | __link_buffer(b, block, LIST_CLEAN); | |
1008 | ||
1009 | if (nf == NF_FRESH) { | |
1010 | b->state = 0; | |
1011 | return b; | |
1012 | } | |
1013 | ||
1014 | b->state = 1 << B_READING; | |
1015 | *need_submit = 1; | |
1016 | ||
1017 | return b; | |
a66cc28f MP |
1018 | |
1019 | found_buffer: | |
1020 | if (nf == NF_PREFETCH) | |
1021 | return NULL; | |
1022 | /* | |
1023 | * Note: it is essential that we don't wait for the buffer to be | |
1024 | * read if dm_bufio_get function is used. Both dm_bufio_get and | |
1025 | * dm_bufio_prefetch can be used in the driver request routine. | |
1026 | * If the user called both dm_bufio_prefetch and dm_bufio_get on | |
1027 | * the same buffer, it would deadlock if we waited. | |
1028 | */ | |
1029 | if (nf == NF_GET && unlikely(test_bit(B_READING, &b->state))) | |
1030 | return NULL; | |
1031 | ||
1032 | b->hold_count++; | |
1033 | __relink_lru(b, test_bit(B_DIRTY, &b->state) || | |
1034 | test_bit(B_WRITING, &b->state)); | |
1035 | return b; | |
95d402f0 MP |
1036 | } |
1037 | ||
1038 | /* | |
1039 | * The endio routine for reading: set the error, clear the bit and wake up | |
1040 | * anyone waiting on the buffer. | |
1041 | */ | |
4246a0b6 | 1042 | static void read_endio(struct bio *bio) |
95d402f0 MP |
1043 | { |
1044 | struct dm_buffer *b = container_of(bio, struct dm_buffer, bio); | |
1045 | ||
4246a0b6 | 1046 | b->read_error = bio->bi_error; |
95d402f0 MP |
1047 | |
1048 | BUG_ON(!test_bit(B_READING, &b->state)); | |
1049 | ||
4e857c58 | 1050 | smp_mb__before_atomic(); |
95d402f0 | 1051 | clear_bit(B_READING, &b->state); |
4e857c58 | 1052 | smp_mb__after_atomic(); |
95d402f0 MP |
1053 | |
1054 | wake_up_bit(&b->state, B_READING); | |
1055 | } | |
1056 | ||
1057 | /* | |
1058 | * A common routine for dm_bufio_new and dm_bufio_read. Operation of these | |
1059 | * functions is similar except that dm_bufio_new doesn't read the | |
1060 | * buffer from the disk (assuming that the caller overwrites all the data | |
1061 | * and uses dm_bufio_mark_buffer_dirty to write new data back). | |
1062 | */ | |
1063 | static void *new_read(struct dm_bufio_client *c, sector_t block, | |
1064 | enum new_flag nf, struct dm_buffer **bp) | |
1065 | { | |
1066 | int need_submit; | |
1067 | struct dm_buffer *b; | |
1068 | ||
2480945c MP |
1069 | LIST_HEAD(write_list); |
1070 | ||
95d402f0 | 1071 | dm_bufio_lock(c); |
2480945c | 1072 | b = __bufio_new(c, block, nf, &need_submit, &write_list); |
86bad0c7 MP |
1073 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
1074 | if (b && b->hold_count == 1) | |
1075 | buffer_record_stack(b); | |
1076 | #endif | |
95d402f0 MP |
1077 | dm_bufio_unlock(c); |
1078 | ||
2480945c MP |
1079 | __flush_write_list(&write_list); |
1080 | ||
a66cc28f | 1081 | if (!b) |
f98c8f79 | 1082 | return NULL; |
95d402f0 MP |
1083 | |
1084 | if (need_submit) | |
1085 | submit_io(b, READ, b->block, read_endio); | |
1086 | ||
74316201 | 1087 | wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE); |
95d402f0 MP |
1088 | |
1089 | if (b->read_error) { | |
1090 | int error = b->read_error; | |
1091 | ||
1092 | dm_bufio_release(b); | |
1093 | ||
1094 | return ERR_PTR(error); | |
1095 | } | |
1096 | ||
1097 | *bp = b; | |
1098 | ||
1099 | return b->data; | |
1100 | } | |
1101 | ||
1102 | void *dm_bufio_get(struct dm_bufio_client *c, sector_t block, | |
1103 | struct dm_buffer **bp) | |
1104 | { | |
1105 | return new_read(c, block, NF_GET, bp); | |
1106 | } | |
1107 | EXPORT_SYMBOL_GPL(dm_bufio_get); | |
1108 | ||
1109 | void *dm_bufio_read(struct dm_bufio_client *c, sector_t block, | |
1110 | struct dm_buffer **bp) | |
1111 | { | |
1112 | BUG_ON(dm_bufio_in_request()); | |
1113 | ||
1114 | return new_read(c, block, NF_READ, bp); | |
1115 | } | |
1116 | EXPORT_SYMBOL_GPL(dm_bufio_read); | |
1117 | ||
1118 | void *dm_bufio_new(struct dm_bufio_client *c, sector_t block, | |
1119 | struct dm_buffer **bp) | |
1120 | { | |
1121 | BUG_ON(dm_bufio_in_request()); | |
1122 | ||
1123 | return new_read(c, block, NF_FRESH, bp); | |
1124 | } | |
1125 | EXPORT_SYMBOL_GPL(dm_bufio_new); | |
1126 | ||
a66cc28f MP |
1127 | void dm_bufio_prefetch(struct dm_bufio_client *c, |
1128 | sector_t block, unsigned n_blocks) | |
1129 | { | |
1130 | struct blk_plug plug; | |
1131 | ||
2480945c MP |
1132 | LIST_HEAD(write_list); |
1133 | ||
3b6b7813 MP |
1134 | BUG_ON(dm_bufio_in_request()); |
1135 | ||
a66cc28f MP |
1136 | blk_start_plug(&plug); |
1137 | dm_bufio_lock(c); | |
1138 | ||
1139 | for (; n_blocks--; block++) { | |
1140 | int need_submit; | |
1141 | struct dm_buffer *b; | |
2480945c MP |
1142 | b = __bufio_new(c, block, NF_PREFETCH, &need_submit, |
1143 | &write_list); | |
1144 | if (unlikely(!list_empty(&write_list))) { | |
1145 | dm_bufio_unlock(c); | |
1146 | blk_finish_plug(&plug); | |
1147 | __flush_write_list(&write_list); | |
1148 | blk_start_plug(&plug); | |
1149 | dm_bufio_lock(c); | |
1150 | } | |
a66cc28f MP |
1151 | if (unlikely(b != NULL)) { |
1152 | dm_bufio_unlock(c); | |
1153 | ||
1154 | if (need_submit) | |
1155 | submit_io(b, READ, b->block, read_endio); | |
1156 | dm_bufio_release(b); | |
1157 | ||
7cd32674 | 1158 | cond_resched(); |
a66cc28f MP |
1159 | |
1160 | if (!n_blocks) | |
1161 | goto flush_plug; | |
1162 | dm_bufio_lock(c); | |
1163 | } | |
a66cc28f MP |
1164 | } |
1165 | ||
1166 | dm_bufio_unlock(c); | |
1167 | ||
1168 | flush_plug: | |
1169 | blk_finish_plug(&plug); | |
1170 | } | |
1171 | EXPORT_SYMBOL_GPL(dm_bufio_prefetch); | |
1172 | ||
95d402f0 MP |
1173 | void dm_bufio_release(struct dm_buffer *b) |
1174 | { | |
1175 | struct dm_bufio_client *c = b->c; | |
1176 | ||
1177 | dm_bufio_lock(c); | |
1178 | ||
95d402f0 MP |
1179 | BUG_ON(!b->hold_count); |
1180 | ||
1181 | b->hold_count--; | |
1182 | if (!b->hold_count) { | |
1183 | wake_up(&c->free_buffer_wait); | |
1184 | ||
1185 | /* | |
1186 | * If there were errors on the buffer, and the buffer is not | |
1187 | * to be written, free the buffer. There is no point in caching | |
1188 | * invalid buffer. | |
1189 | */ | |
1190 | if ((b->read_error || b->write_error) && | |
a66cc28f | 1191 | !test_bit(B_READING, &b->state) && |
95d402f0 MP |
1192 | !test_bit(B_WRITING, &b->state) && |
1193 | !test_bit(B_DIRTY, &b->state)) { | |
1194 | __unlink_buffer(b); | |
1195 | __free_buffer_wake(b); | |
1196 | } | |
1197 | } | |
1198 | ||
1199 | dm_bufio_unlock(c); | |
1200 | } | |
1201 | EXPORT_SYMBOL_GPL(dm_bufio_release); | |
1202 | ||
1203 | void dm_bufio_mark_buffer_dirty(struct dm_buffer *b) | |
1204 | { | |
1205 | struct dm_bufio_client *c = b->c; | |
1206 | ||
1207 | dm_bufio_lock(c); | |
1208 | ||
a66cc28f MP |
1209 | BUG_ON(test_bit(B_READING, &b->state)); |
1210 | ||
95d402f0 MP |
1211 | if (!test_and_set_bit(B_DIRTY, &b->state)) |
1212 | __relink_lru(b, LIST_DIRTY); | |
1213 | ||
1214 | dm_bufio_unlock(c); | |
1215 | } | |
1216 | EXPORT_SYMBOL_GPL(dm_bufio_mark_buffer_dirty); | |
1217 | ||
1218 | void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c) | |
1219 | { | |
2480945c MP |
1220 | LIST_HEAD(write_list); |
1221 | ||
95d402f0 MP |
1222 | BUG_ON(dm_bufio_in_request()); |
1223 | ||
1224 | dm_bufio_lock(c); | |
2480945c | 1225 | __write_dirty_buffers_async(c, 0, &write_list); |
95d402f0 | 1226 | dm_bufio_unlock(c); |
2480945c | 1227 | __flush_write_list(&write_list); |
95d402f0 MP |
1228 | } |
1229 | EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers_async); | |
1230 | ||
1231 | /* | |
1232 | * For performance, it is essential that the buffers are written asynchronously | |
1233 | * and simultaneously (so that the block layer can merge the writes) and then | |
1234 | * waited upon. | |
1235 | * | |
1236 | * Finally, we flush hardware disk cache. | |
1237 | */ | |
1238 | int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c) | |
1239 | { | |
1240 | int a, f; | |
1241 | unsigned long buffers_processed = 0; | |
1242 | struct dm_buffer *b, *tmp; | |
1243 | ||
2480945c MP |
1244 | LIST_HEAD(write_list); |
1245 | ||
1246 | dm_bufio_lock(c); | |
1247 | __write_dirty_buffers_async(c, 0, &write_list); | |
1248 | dm_bufio_unlock(c); | |
1249 | __flush_write_list(&write_list); | |
95d402f0 | 1250 | dm_bufio_lock(c); |
95d402f0 MP |
1251 | |
1252 | again: | |
1253 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { | |
1254 | int dropped_lock = 0; | |
1255 | ||
1256 | if (buffers_processed < c->n_buffers[LIST_DIRTY]) | |
1257 | buffers_processed++; | |
1258 | ||
1259 | BUG_ON(test_bit(B_READING, &b->state)); | |
1260 | ||
1261 | if (test_bit(B_WRITING, &b->state)) { | |
1262 | if (buffers_processed < c->n_buffers[LIST_DIRTY]) { | |
1263 | dropped_lock = 1; | |
1264 | b->hold_count++; | |
1265 | dm_bufio_unlock(c); | |
74316201 N |
1266 | wait_on_bit_io(&b->state, B_WRITING, |
1267 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1268 | dm_bufio_lock(c); |
1269 | b->hold_count--; | |
1270 | } else | |
74316201 N |
1271 | wait_on_bit_io(&b->state, B_WRITING, |
1272 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1273 | } |
1274 | ||
1275 | if (!test_bit(B_DIRTY, &b->state) && | |
1276 | !test_bit(B_WRITING, &b->state)) | |
1277 | __relink_lru(b, LIST_CLEAN); | |
1278 | ||
7cd32674 | 1279 | cond_resched(); |
95d402f0 MP |
1280 | |
1281 | /* | |
1282 | * If we dropped the lock, the list is no longer consistent, | |
1283 | * so we must restart the search. | |
1284 | * | |
1285 | * In the most common case, the buffer just processed is | |
1286 | * relinked to the clean list, so we won't loop scanning the | |
1287 | * same buffer again and again. | |
1288 | * | |
1289 | * This may livelock if there is another thread simultaneously | |
1290 | * dirtying buffers, so we count the number of buffers walked | |
1291 | * and if it exceeds the total number of buffers, it means that | |
1292 | * someone is doing some writes simultaneously with us. In | |
1293 | * this case, stop, dropping the lock. | |
1294 | */ | |
1295 | if (dropped_lock) | |
1296 | goto again; | |
1297 | } | |
1298 | wake_up(&c->free_buffer_wait); | |
1299 | dm_bufio_unlock(c); | |
1300 | ||
1301 | a = xchg(&c->async_write_error, 0); | |
1302 | f = dm_bufio_issue_flush(c); | |
1303 | if (a) | |
1304 | return a; | |
1305 | ||
1306 | return f; | |
1307 | } | |
1308 | EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers); | |
1309 | ||
1310 | /* | |
1311 | * Use dm-io to send and empty barrier flush the device. | |
1312 | */ | |
1313 | int dm_bufio_issue_flush(struct dm_bufio_client *c) | |
1314 | { | |
1315 | struct dm_io_request io_req = { | |
e6047149 | 1316 | .bi_op = REQ_OP_WRITE, |
70fd7614 | 1317 | .bi_op_flags = REQ_PREFLUSH, |
95d402f0 MP |
1318 | .mem.type = DM_IO_KMEM, |
1319 | .mem.ptr.addr = NULL, | |
1320 | .client = c->dm_io, | |
1321 | }; | |
1322 | struct dm_io_region io_reg = { | |
1323 | .bdev = c->bdev, | |
1324 | .sector = 0, | |
1325 | .count = 0, | |
1326 | }; | |
1327 | ||
1328 | BUG_ON(dm_bufio_in_request()); | |
1329 | ||
1330 | return dm_io(&io_req, 1, &io_reg, NULL); | |
1331 | } | |
1332 | EXPORT_SYMBOL_GPL(dm_bufio_issue_flush); | |
1333 | ||
1334 | /* | |
1335 | * We first delete any other buffer that may be at that new location. | |
1336 | * | |
1337 | * Then, we write the buffer to the original location if it was dirty. | |
1338 | * | |
1339 | * Then, if we are the only one who is holding the buffer, relink the buffer | |
1340 | * in the hash queue for the new location. | |
1341 | * | |
1342 | * If there was someone else holding the buffer, we write it to the new | |
1343 | * location but not relink it, because that other user needs to have the buffer | |
1344 | * at the same place. | |
1345 | */ | |
1346 | void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block) | |
1347 | { | |
1348 | struct dm_bufio_client *c = b->c; | |
1349 | struct dm_buffer *new; | |
1350 | ||
1351 | BUG_ON(dm_bufio_in_request()); | |
1352 | ||
1353 | dm_bufio_lock(c); | |
1354 | ||
1355 | retry: | |
1356 | new = __find(c, new_block); | |
1357 | if (new) { | |
1358 | if (new->hold_count) { | |
1359 | __wait_for_free_buffer(c); | |
1360 | goto retry; | |
1361 | } | |
1362 | ||
1363 | /* | |
1364 | * FIXME: Is there any point waiting for a write that's going | |
1365 | * to be overwritten in a bit? | |
1366 | */ | |
1367 | __make_buffer_clean(new); | |
1368 | __unlink_buffer(new); | |
1369 | __free_buffer_wake(new); | |
1370 | } | |
1371 | ||
1372 | BUG_ON(!b->hold_count); | |
1373 | BUG_ON(test_bit(B_READING, &b->state)); | |
1374 | ||
2480945c | 1375 | __write_dirty_buffer(b, NULL); |
95d402f0 | 1376 | if (b->hold_count == 1) { |
74316201 N |
1377 | wait_on_bit_io(&b->state, B_WRITING, |
1378 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1379 | set_bit(B_DIRTY, &b->state); |
1380 | __unlink_buffer(b); | |
1381 | __link_buffer(b, new_block, LIST_DIRTY); | |
1382 | } else { | |
1383 | sector_t old_block; | |
74316201 N |
1384 | wait_on_bit_lock_io(&b->state, B_WRITING, |
1385 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1386 | /* |
1387 | * Relink buffer to "new_block" so that write_callback | |
1388 | * sees "new_block" as a block number. | |
1389 | * After the write, link the buffer back to old_block. | |
1390 | * All this must be done in bufio lock, so that block number | |
1391 | * change isn't visible to other threads. | |
1392 | */ | |
1393 | old_block = b->block; | |
1394 | __unlink_buffer(b); | |
1395 | __link_buffer(b, new_block, b->list_mode); | |
1396 | submit_io(b, WRITE, new_block, write_endio); | |
74316201 N |
1397 | wait_on_bit_io(&b->state, B_WRITING, |
1398 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1399 | __unlink_buffer(b); |
1400 | __link_buffer(b, old_block, b->list_mode); | |
1401 | } | |
1402 | ||
1403 | dm_bufio_unlock(c); | |
1404 | dm_bufio_release(b); | |
1405 | } | |
1406 | EXPORT_SYMBOL_GPL(dm_bufio_release_move); | |
1407 | ||
55494bf2 MP |
1408 | /* |
1409 | * Free the given buffer. | |
1410 | * | |
1411 | * This is just a hint, if the buffer is in use or dirty, this function | |
1412 | * does nothing. | |
1413 | */ | |
1414 | void dm_bufio_forget(struct dm_bufio_client *c, sector_t block) | |
1415 | { | |
1416 | struct dm_buffer *b; | |
1417 | ||
1418 | dm_bufio_lock(c); | |
1419 | ||
1420 | b = __find(c, block); | |
1421 | if (b && likely(!b->hold_count) && likely(!b->state)) { | |
1422 | __unlink_buffer(b); | |
1423 | __free_buffer_wake(b); | |
1424 | } | |
1425 | ||
1426 | dm_bufio_unlock(c); | |
1427 | } | |
1428 | EXPORT_SYMBOL(dm_bufio_forget); | |
1429 | ||
55b082e6 MP |
1430 | void dm_bufio_set_minimum_buffers(struct dm_bufio_client *c, unsigned n) |
1431 | { | |
1432 | c->minimum_buffers = n; | |
1433 | } | |
1434 | EXPORT_SYMBOL(dm_bufio_set_minimum_buffers); | |
1435 | ||
95d402f0 MP |
1436 | unsigned dm_bufio_get_block_size(struct dm_bufio_client *c) |
1437 | { | |
1438 | return c->block_size; | |
1439 | } | |
1440 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_size); | |
1441 | ||
1442 | sector_t dm_bufio_get_device_size(struct dm_bufio_client *c) | |
1443 | { | |
1444 | return i_size_read(c->bdev->bd_inode) >> | |
1445 | (SECTOR_SHIFT + c->sectors_per_block_bits); | |
1446 | } | |
1447 | EXPORT_SYMBOL_GPL(dm_bufio_get_device_size); | |
1448 | ||
1449 | sector_t dm_bufio_get_block_number(struct dm_buffer *b) | |
1450 | { | |
1451 | return b->block; | |
1452 | } | |
1453 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_number); | |
1454 | ||
1455 | void *dm_bufio_get_block_data(struct dm_buffer *b) | |
1456 | { | |
1457 | return b->data; | |
1458 | } | |
1459 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_data); | |
1460 | ||
1461 | void *dm_bufio_get_aux_data(struct dm_buffer *b) | |
1462 | { | |
1463 | return b + 1; | |
1464 | } | |
1465 | EXPORT_SYMBOL_GPL(dm_bufio_get_aux_data); | |
1466 | ||
1467 | struct dm_bufio_client *dm_bufio_get_client(struct dm_buffer *b) | |
1468 | { | |
1469 | return b->c; | |
1470 | } | |
1471 | EXPORT_SYMBOL_GPL(dm_bufio_get_client); | |
1472 | ||
1473 | static void drop_buffers(struct dm_bufio_client *c) | |
1474 | { | |
1475 | struct dm_buffer *b; | |
1476 | int i; | |
86bad0c7 | 1477 | bool warned = false; |
95d402f0 MP |
1478 | |
1479 | BUG_ON(dm_bufio_in_request()); | |
1480 | ||
1481 | /* | |
1482 | * An optimization so that the buffers are not written one-by-one. | |
1483 | */ | |
1484 | dm_bufio_write_dirty_buffers_async(c); | |
1485 | ||
1486 | dm_bufio_lock(c); | |
1487 | ||
1488 | while ((b = __get_unclaimed_buffer(c))) | |
1489 | __free_buffer_wake(b); | |
1490 | ||
1491 | for (i = 0; i < LIST_SIZE; i++) | |
86bad0c7 MP |
1492 | list_for_each_entry(b, &c->lru[i], lru_list) { |
1493 | WARN_ON(!warned); | |
1494 | warned = true; | |
95d402f0 MP |
1495 | DMERR("leaked buffer %llx, hold count %u, list %d", |
1496 | (unsigned long long)b->block, b->hold_count, i); | |
86bad0c7 MP |
1497 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
1498 | print_stack_trace(&b->stack_trace, 1); | |
1499 | b->hold_count = 0; /* mark unclaimed to avoid BUG_ON below */ | |
1500 | #endif | |
1501 | } | |
1502 | ||
1503 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING | |
1504 | while ((b = __get_unclaimed_buffer(c))) | |
1505 | __free_buffer_wake(b); | |
1506 | #endif | |
95d402f0 MP |
1507 | |
1508 | for (i = 0; i < LIST_SIZE; i++) | |
1509 | BUG_ON(!list_empty(&c->lru[i])); | |
1510 | ||
1511 | dm_bufio_unlock(c); | |
1512 | } | |
1513 | ||
1514 | /* | |
33096a78 JT |
1515 | * We may not be able to evict this buffer if IO pending or the client |
1516 | * is still using it. Caller is expected to know buffer is too old. | |
1517 | * | |
9d28eb12 MP |
1518 | * And if GFP_NOFS is used, we must not do any I/O because we hold |
1519 | * dm_bufio_clients_lock and we would risk deadlock if the I/O gets | |
1520 | * rerouted to different bufio client. | |
95d402f0 | 1521 | */ |
33096a78 | 1522 | static bool __try_evict_buffer(struct dm_buffer *b, gfp_t gfp) |
95d402f0 | 1523 | { |
9d28eb12 | 1524 | if (!(gfp & __GFP_FS)) { |
95d402f0 MP |
1525 | if (test_bit(B_READING, &b->state) || |
1526 | test_bit(B_WRITING, &b->state) || | |
1527 | test_bit(B_DIRTY, &b->state)) | |
33096a78 | 1528 | return false; |
95d402f0 MP |
1529 | } |
1530 | ||
1531 | if (b->hold_count) | |
33096a78 | 1532 | return false; |
95d402f0 MP |
1533 | |
1534 | __make_buffer_clean(b); | |
1535 | __unlink_buffer(b); | |
1536 | __free_buffer_wake(b); | |
1537 | ||
33096a78 | 1538 | return true; |
95d402f0 MP |
1539 | } |
1540 | ||
33096a78 JT |
1541 | static unsigned get_retain_buffers(struct dm_bufio_client *c) |
1542 | { | |
1543 | unsigned retain_bytes = ACCESS_ONCE(dm_bufio_retain_bytes); | |
1544 | return retain_bytes / c->block_size; | |
1545 | } | |
1546 | ||
1547 | static unsigned long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan, | |
1548 | gfp_t gfp_mask) | |
95d402f0 MP |
1549 | { |
1550 | int l; | |
1551 | struct dm_buffer *b, *tmp; | |
33096a78 JT |
1552 | unsigned long freed = 0; |
1553 | unsigned long count = nr_to_scan; | |
1554 | unsigned retain_target = get_retain_buffers(c); | |
95d402f0 MP |
1555 | |
1556 | for (l = 0; l < LIST_SIZE; l++) { | |
7dc19d5a | 1557 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list) { |
33096a78 JT |
1558 | if (__try_evict_buffer(b, gfp_mask)) |
1559 | freed++; | |
1560 | if (!--nr_to_scan || ((count - freed) <= retain_target)) | |
0e825862 | 1561 | return freed; |
7cd32674 | 1562 | cond_resched(); |
7dc19d5a | 1563 | } |
95d402f0 | 1564 | } |
7dc19d5a | 1565 | return freed; |
95d402f0 MP |
1566 | } |
1567 | ||
7dc19d5a DC |
1568 | static unsigned long |
1569 | dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) | |
95d402f0 | 1570 | { |
7dc19d5a DC |
1571 | struct dm_bufio_client *c; |
1572 | unsigned long freed; | |
95d402f0 | 1573 | |
7dc19d5a | 1574 | c = container_of(shrink, struct dm_bufio_client, shrinker); |
9d28eb12 | 1575 | if (sc->gfp_mask & __GFP_FS) |
95d402f0 MP |
1576 | dm_bufio_lock(c); |
1577 | else if (!dm_bufio_trylock(c)) | |
7dc19d5a | 1578 | return SHRINK_STOP; |
95d402f0 | 1579 | |
7dc19d5a DC |
1580 | freed = __scan(c, sc->nr_to_scan, sc->gfp_mask); |
1581 | dm_bufio_unlock(c); | |
1582 | return freed; | |
1583 | } | |
95d402f0 | 1584 | |
7dc19d5a DC |
1585 | static unsigned long |
1586 | dm_bufio_shrink_count(struct shrinker *shrink, struct shrink_control *sc) | |
1587 | { | |
1588 | struct dm_bufio_client *c; | |
1589 | unsigned long count; | |
95d402f0 | 1590 | |
7dc19d5a | 1591 | c = container_of(shrink, struct dm_bufio_client, shrinker); |
9d28eb12 | 1592 | if (sc->gfp_mask & __GFP_FS) |
7dc19d5a DC |
1593 | dm_bufio_lock(c); |
1594 | else if (!dm_bufio_trylock(c)) | |
1595 | return 0; | |
95d402f0 | 1596 | |
7dc19d5a DC |
1597 | count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY]; |
1598 | dm_bufio_unlock(c); | |
1599 | return count; | |
95d402f0 MP |
1600 | } |
1601 | ||
1602 | /* | |
1603 | * Create the buffering interface | |
1604 | */ | |
1605 | struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsigned block_size, | |
1606 | unsigned reserved_buffers, unsigned aux_size, | |
1607 | void (*alloc_callback)(struct dm_buffer *), | |
1608 | void (*write_callback)(struct dm_buffer *)) | |
1609 | { | |
1610 | int r; | |
1611 | struct dm_bufio_client *c; | |
1612 | unsigned i; | |
1613 | ||
1614 | BUG_ON(block_size < 1 << SECTOR_SHIFT || | |
1615 | (block_size & (block_size - 1))); | |
1616 | ||
d8c712ea | 1617 | c = kzalloc(sizeof(*c), GFP_KERNEL); |
95d402f0 MP |
1618 | if (!c) { |
1619 | r = -ENOMEM; | |
1620 | goto bad_client; | |
1621 | } | |
4e420c45 | 1622 | c->buffer_tree = RB_ROOT; |
95d402f0 MP |
1623 | |
1624 | c->bdev = bdev; | |
1625 | c->block_size = block_size; | |
a3d939ae MP |
1626 | c->sectors_per_block_bits = __ffs(block_size) - SECTOR_SHIFT; |
1627 | c->pages_per_block_bits = (__ffs(block_size) >= PAGE_SHIFT) ? | |
1628 | __ffs(block_size) - PAGE_SHIFT : 0; | |
1629 | c->blocks_per_page_bits = (__ffs(block_size) < PAGE_SHIFT ? | |
1630 | PAGE_SHIFT - __ffs(block_size) : 0); | |
95d402f0 MP |
1631 | |
1632 | c->aux_size = aux_size; | |
1633 | c->alloc_callback = alloc_callback; | |
1634 | c->write_callback = write_callback; | |
1635 | ||
1636 | for (i = 0; i < LIST_SIZE; i++) { | |
1637 | INIT_LIST_HEAD(&c->lru[i]); | |
1638 | c->n_buffers[i] = 0; | |
1639 | } | |
1640 | ||
95d402f0 MP |
1641 | mutex_init(&c->lock); |
1642 | INIT_LIST_HEAD(&c->reserved_buffers); | |
1643 | c->need_reserved_buffers = reserved_buffers; | |
1644 | ||
55b082e6 MP |
1645 | c->minimum_buffers = DM_BUFIO_MIN_BUFFERS; |
1646 | ||
95d402f0 MP |
1647 | init_waitqueue_head(&c->free_buffer_wait); |
1648 | c->async_write_error = 0; | |
1649 | ||
1650 | c->dm_io = dm_io_client_create(); | |
1651 | if (IS_ERR(c->dm_io)) { | |
1652 | r = PTR_ERR(c->dm_io); | |
1653 | goto bad_dm_io; | |
1654 | } | |
1655 | ||
1656 | mutex_lock(&dm_bufio_clients_lock); | |
1657 | if (c->blocks_per_page_bits) { | |
1658 | if (!DM_BUFIO_CACHE_NAME(c)) { | |
1659 | DM_BUFIO_CACHE_NAME(c) = kasprintf(GFP_KERNEL, "dm_bufio_cache-%u", c->block_size); | |
1660 | if (!DM_BUFIO_CACHE_NAME(c)) { | |
1661 | r = -ENOMEM; | |
1662 | mutex_unlock(&dm_bufio_clients_lock); | |
1663 | goto bad_cache; | |
1664 | } | |
1665 | } | |
1666 | ||
1667 | if (!DM_BUFIO_CACHE(c)) { | |
1668 | DM_BUFIO_CACHE(c) = kmem_cache_create(DM_BUFIO_CACHE_NAME(c), | |
1669 | c->block_size, | |
1670 | c->block_size, 0, NULL); | |
1671 | if (!DM_BUFIO_CACHE(c)) { | |
1672 | r = -ENOMEM; | |
1673 | mutex_unlock(&dm_bufio_clients_lock); | |
1674 | goto bad_cache; | |
1675 | } | |
1676 | } | |
1677 | } | |
1678 | mutex_unlock(&dm_bufio_clients_lock); | |
1679 | ||
1680 | while (c->need_reserved_buffers) { | |
1681 | struct dm_buffer *b = alloc_buffer(c, GFP_KERNEL); | |
1682 | ||
1683 | if (!b) { | |
1684 | r = -ENOMEM; | |
1685 | goto bad_buffer; | |
1686 | } | |
1687 | __free_buffer_wake(b); | |
1688 | } | |
1689 | ||
1690 | mutex_lock(&dm_bufio_clients_lock); | |
1691 | dm_bufio_client_count++; | |
1692 | list_add(&c->client_list, &dm_bufio_all_clients); | |
1693 | __cache_size_refresh(); | |
1694 | mutex_unlock(&dm_bufio_clients_lock); | |
1695 | ||
7dc19d5a DC |
1696 | c->shrinker.count_objects = dm_bufio_shrink_count; |
1697 | c->shrinker.scan_objects = dm_bufio_shrink_scan; | |
95d402f0 MP |
1698 | c->shrinker.seeks = 1; |
1699 | c->shrinker.batch = 0; | |
1700 | register_shrinker(&c->shrinker); | |
1701 | ||
1702 | return c; | |
1703 | ||
1704 | bad_buffer: | |
1705 | bad_cache: | |
1706 | while (!list_empty(&c->reserved_buffers)) { | |
1707 | struct dm_buffer *b = list_entry(c->reserved_buffers.next, | |
1708 | struct dm_buffer, lru_list); | |
1709 | list_del(&b->lru_list); | |
1710 | free_buffer(b); | |
1711 | } | |
1712 | dm_io_client_destroy(c->dm_io); | |
1713 | bad_dm_io: | |
95d402f0 MP |
1714 | kfree(c); |
1715 | bad_client: | |
1716 | return ERR_PTR(r); | |
1717 | } | |
1718 | EXPORT_SYMBOL_GPL(dm_bufio_client_create); | |
1719 | ||
1720 | /* | |
1721 | * Free the buffering interface. | |
1722 | * It is required that there are no references on any buffers. | |
1723 | */ | |
1724 | void dm_bufio_client_destroy(struct dm_bufio_client *c) | |
1725 | { | |
1726 | unsigned i; | |
1727 | ||
1728 | drop_buffers(c); | |
1729 | ||
1730 | unregister_shrinker(&c->shrinker); | |
1731 | ||
1732 | mutex_lock(&dm_bufio_clients_lock); | |
1733 | ||
1734 | list_del(&c->client_list); | |
1735 | dm_bufio_client_count--; | |
1736 | __cache_size_refresh(); | |
1737 | ||
1738 | mutex_unlock(&dm_bufio_clients_lock); | |
1739 | ||
4e420c45 | 1740 | BUG_ON(!RB_EMPTY_ROOT(&c->buffer_tree)); |
95d402f0 MP |
1741 | BUG_ON(c->need_reserved_buffers); |
1742 | ||
1743 | while (!list_empty(&c->reserved_buffers)) { | |
1744 | struct dm_buffer *b = list_entry(c->reserved_buffers.next, | |
1745 | struct dm_buffer, lru_list); | |
1746 | list_del(&b->lru_list); | |
1747 | free_buffer(b); | |
1748 | } | |
1749 | ||
1750 | for (i = 0; i < LIST_SIZE; i++) | |
1751 | if (c->n_buffers[i]) | |
1752 | DMERR("leaked buffer count %d: %ld", i, c->n_buffers[i]); | |
1753 | ||
1754 | for (i = 0; i < LIST_SIZE; i++) | |
1755 | BUG_ON(c->n_buffers[i]); | |
1756 | ||
1757 | dm_io_client_destroy(c->dm_io); | |
95d402f0 MP |
1758 | kfree(c); |
1759 | } | |
1760 | EXPORT_SYMBOL_GPL(dm_bufio_client_destroy); | |
1761 | ||
33096a78 | 1762 | static unsigned get_max_age_hz(void) |
95d402f0 | 1763 | { |
33096a78 | 1764 | unsigned max_age = ACCESS_ONCE(dm_bufio_max_age); |
95d402f0 | 1765 | |
33096a78 JT |
1766 | if (max_age > UINT_MAX / HZ) |
1767 | max_age = UINT_MAX / HZ; | |
95d402f0 | 1768 | |
33096a78 JT |
1769 | return max_age * HZ; |
1770 | } | |
95d402f0 | 1771 | |
33096a78 JT |
1772 | static bool older_than(struct dm_buffer *b, unsigned long age_hz) |
1773 | { | |
f495339c | 1774 | return time_after_eq(jiffies, b->last_accessed + age_hz); |
33096a78 JT |
1775 | } |
1776 | ||
1777 | static void __evict_old_buffers(struct dm_bufio_client *c, unsigned long age_hz) | |
1778 | { | |
1779 | struct dm_buffer *b, *tmp; | |
1780 | unsigned retain_target = get_retain_buffers(c); | |
1781 | unsigned count; | |
1782 | ||
1783 | dm_bufio_lock(c); | |
1784 | ||
1785 | count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY]; | |
1786 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_CLEAN], lru_list) { | |
1787 | if (count <= retain_target) | |
1788 | break; | |
1789 | ||
1790 | if (!older_than(b, age_hz)) | |
1791 | break; | |
1792 | ||
1793 | if (__try_evict_buffer(b, 0)) | |
1794 | count--; | |
95d402f0 | 1795 | |
7cd32674 | 1796 | cond_resched(); |
95d402f0 | 1797 | } |
33096a78 JT |
1798 | |
1799 | dm_bufio_unlock(c); | |
1800 | } | |
1801 | ||
1802 | static void cleanup_old_buffers(void) | |
1803 | { | |
1804 | unsigned long max_age_hz = get_max_age_hz(); | |
1805 | struct dm_bufio_client *c; | |
1806 | ||
1807 | mutex_lock(&dm_bufio_clients_lock); | |
1808 | ||
1809 | list_for_each_entry(c, &dm_bufio_all_clients, client_list) | |
1810 | __evict_old_buffers(c, max_age_hz); | |
1811 | ||
95d402f0 MP |
1812 | mutex_unlock(&dm_bufio_clients_lock); |
1813 | } | |
1814 | ||
1815 | static struct workqueue_struct *dm_bufio_wq; | |
1816 | static struct delayed_work dm_bufio_work; | |
1817 | ||
1818 | static void work_fn(struct work_struct *w) | |
1819 | { | |
1820 | cleanup_old_buffers(); | |
1821 | ||
1822 | queue_delayed_work(dm_bufio_wq, &dm_bufio_work, | |
1823 | DM_BUFIO_WORK_TIMER_SECS * HZ); | |
1824 | } | |
1825 | ||
1826 | /*---------------------------------------------------------------- | |
1827 | * Module setup | |
1828 | *--------------------------------------------------------------*/ | |
1829 | ||
1830 | /* | |
1831 | * This is called only once for the whole dm_bufio module. | |
1832 | * It initializes memory limit. | |
1833 | */ | |
1834 | static int __init dm_bufio_init(void) | |
1835 | { | |
1836 | __u64 mem; | |
1837 | ||
4cb57ab4 MP |
1838 | dm_bufio_allocated_kmem_cache = 0; |
1839 | dm_bufio_allocated_get_free_pages = 0; | |
1840 | dm_bufio_allocated_vmalloc = 0; | |
1841 | dm_bufio_current_allocated = 0; | |
1842 | ||
95d402f0 MP |
1843 | memset(&dm_bufio_caches, 0, sizeof dm_bufio_caches); |
1844 | memset(&dm_bufio_cache_names, 0, sizeof dm_bufio_cache_names); | |
1845 | ||
1846 | mem = (__u64)((totalram_pages - totalhigh_pages) * | |
1847 | DM_BUFIO_MEMORY_PERCENT / 100) << PAGE_SHIFT; | |
1848 | ||
1849 | if (mem > ULONG_MAX) | |
1850 | mem = ULONG_MAX; | |
1851 | ||
1852 | #ifdef CONFIG_MMU | |
1853 | /* | |
1854 | * Get the size of vmalloc space the same way as VMALLOC_TOTAL | |
1855 | * in fs/proc/internal.h | |
1856 | */ | |
1857 | if (mem > (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100) | |
1858 | mem = (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100; | |
1859 | #endif | |
1860 | ||
1861 | dm_bufio_default_cache_size = mem; | |
1862 | ||
1863 | mutex_lock(&dm_bufio_clients_lock); | |
1864 | __cache_size_refresh(); | |
1865 | mutex_unlock(&dm_bufio_clients_lock); | |
1866 | ||
edd1ea2a | 1867 | dm_bufio_wq = alloc_workqueue("dm_bufio_cache", WQ_MEM_RECLAIM, 0); |
95d402f0 MP |
1868 | if (!dm_bufio_wq) |
1869 | return -ENOMEM; | |
1870 | ||
1871 | INIT_DELAYED_WORK(&dm_bufio_work, work_fn); | |
1872 | queue_delayed_work(dm_bufio_wq, &dm_bufio_work, | |
1873 | DM_BUFIO_WORK_TIMER_SECS * HZ); | |
1874 | ||
1875 | return 0; | |
1876 | } | |
1877 | ||
1878 | /* | |
1879 | * This is called once when unloading the dm_bufio module. | |
1880 | */ | |
1881 | static void __exit dm_bufio_exit(void) | |
1882 | { | |
1883 | int bug = 0; | |
1884 | int i; | |
1885 | ||
1886 | cancel_delayed_work_sync(&dm_bufio_work); | |
1887 | destroy_workqueue(dm_bufio_wq); | |
1888 | ||
6f65985e JL |
1889 | for (i = 0; i < ARRAY_SIZE(dm_bufio_caches); i++) |
1890 | kmem_cache_destroy(dm_bufio_caches[i]); | |
95d402f0 MP |
1891 | |
1892 | for (i = 0; i < ARRAY_SIZE(dm_bufio_cache_names); i++) | |
1893 | kfree(dm_bufio_cache_names[i]); | |
1894 | ||
1895 | if (dm_bufio_client_count) { | |
1896 | DMCRIT("%s: dm_bufio_client_count leaked: %d", | |
1897 | __func__, dm_bufio_client_count); | |
1898 | bug = 1; | |
1899 | } | |
1900 | ||
1901 | if (dm_bufio_current_allocated) { | |
1902 | DMCRIT("%s: dm_bufio_current_allocated leaked: %lu", | |
1903 | __func__, dm_bufio_current_allocated); | |
1904 | bug = 1; | |
1905 | } | |
1906 | ||
1907 | if (dm_bufio_allocated_get_free_pages) { | |
1908 | DMCRIT("%s: dm_bufio_allocated_get_free_pages leaked: %lu", | |
1909 | __func__, dm_bufio_allocated_get_free_pages); | |
1910 | bug = 1; | |
1911 | } | |
1912 | ||
1913 | if (dm_bufio_allocated_vmalloc) { | |
1914 | DMCRIT("%s: dm_bufio_vmalloc leaked: %lu", | |
1915 | __func__, dm_bufio_allocated_vmalloc); | |
1916 | bug = 1; | |
1917 | } | |
1918 | ||
86a49e2d | 1919 | BUG_ON(bug); |
95d402f0 MP |
1920 | } |
1921 | ||
1922 | module_init(dm_bufio_init) | |
1923 | module_exit(dm_bufio_exit) | |
1924 | ||
1925 | module_param_named(max_cache_size_bytes, dm_bufio_cache_size, ulong, S_IRUGO | S_IWUSR); | |
1926 | MODULE_PARM_DESC(max_cache_size_bytes, "Size of metadata cache"); | |
1927 | ||
1928 | module_param_named(max_age_seconds, dm_bufio_max_age, uint, S_IRUGO | S_IWUSR); | |
1929 | MODULE_PARM_DESC(max_age_seconds, "Max age of a buffer in seconds"); | |
33096a78 JT |
1930 | |
1931 | module_param_named(retain_bytes, dm_bufio_retain_bytes, uint, S_IRUGO | S_IWUSR); | |
1932 | MODULE_PARM_DESC(retain_bytes, "Try to keep at least this many bytes cached in memory"); | |
95d402f0 MP |
1933 | |
1934 | module_param_named(peak_allocated_bytes, dm_bufio_peak_allocated, ulong, S_IRUGO | S_IWUSR); | |
1935 | MODULE_PARM_DESC(peak_allocated_bytes, "Tracks the maximum allocated memory"); | |
1936 | ||
1937 | module_param_named(allocated_kmem_cache_bytes, dm_bufio_allocated_kmem_cache, ulong, S_IRUGO); | |
1938 | MODULE_PARM_DESC(allocated_kmem_cache_bytes, "Memory allocated with kmem_cache_alloc"); | |
1939 | ||
1940 | module_param_named(allocated_get_free_pages_bytes, dm_bufio_allocated_get_free_pages, ulong, S_IRUGO); | |
1941 | MODULE_PARM_DESC(allocated_get_free_pages_bytes, "Memory allocated with get_free_pages"); | |
1942 | ||
1943 | module_param_named(allocated_vmalloc_bytes, dm_bufio_allocated_vmalloc, ulong, S_IRUGO); | |
1944 | MODULE_PARM_DESC(allocated_vmalloc_bytes, "Memory allocated with vmalloc"); | |
1945 | ||
1946 | module_param_named(current_allocated_bytes, dm_bufio_current_allocated, ulong, S_IRUGO); | |
1947 | MODULE_PARM_DESC(current_allocated_bytes, "Memory currently used by the cache"); | |
1948 | ||
1949 | MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>"); | |
1950 | MODULE_DESCRIPTION(DM_NAME " buffered I/O library"); | |
1951 | MODULE_LICENSE("GPL"); |