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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 | ||
194 | /* | |
195 | * FIXME Move to sched.h? | |
196 | */ | |
197 | #ifdef CONFIG_PREEMPT_VOLUNTARY | |
198 | # define dm_bufio_cond_resched() \ | |
199 | do { \ | |
200 | if (unlikely(need_resched())) \ | |
201 | _cond_resched(); \ | |
202 | } while (0) | |
203 | #else | |
204 | # define dm_bufio_cond_resched() do { } while (0) | |
205 | #endif | |
206 | ||
207 | /*----------------------------------------------------------------*/ | |
208 | ||
209 | /* | |
210 | * Default cache size: available memory divided by the ratio. | |
211 | */ | |
212 | static unsigned long dm_bufio_default_cache_size; | |
213 | ||
214 | /* | |
215 | * Total cache size set by the user. | |
216 | */ | |
217 | static unsigned long dm_bufio_cache_size; | |
218 | ||
219 | /* | |
220 | * A copy of dm_bufio_cache_size because dm_bufio_cache_size can change | |
221 | * at any time. If it disagrees, the user has changed cache size. | |
222 | */ | |
223 | static unsigned long dm_bufio_cache_size_latch; | |
224 | ||
225 | static DEFINE_SPINLOCK(param_spinlock); | |
226 | ||
227 | /* | |
228 | * Buffers are freed after this timeout | |
229 | */ | |
230 | static unsigned dm_bufio_max_age = DM_BUFIO_DEFAULT_AGE_SECS; | |
33096a78 | 231 | static unsigned dm_bufio_retain_bytes = DM_BUFIO_DEFAULT_RETAIN_BYTES; |
95d402f0 MP |
232 | |
233 | static unsigned long dm_bufio_peak_allocated; | |
234 | static unsigned long dm_bufio_allocated_kmem_cache; | |
235 | static unsigned long dm_bufio_allocated_get_free_pages; | |
236 | static unsigned long dm_bufio_allocated_vmalloc; | |
237 | static unsigned long dm_bufio_current_allocated; | |
238 | ||
239 | /*----------------------------------------------------------------*/ | |
240 | ||
241 | /* | |
242 | * Per-client cache: dm_bufio_cache_size / dm_bufio_client_count | |
243 | */ | |
244 | static unsigned long dm_bufio_cache_size_per_client; | |
245 | ||
246 | /* | |
247 | * The current number of clients. | |
248 | */ | |
249 | static int dm_bufio_client_count; | |
250 | ||
251 | /* | |
252 | * The list of all clients. | |
253 | */ | |
254 | static LIST_HEAD(dm_bufio_all_clients); | |
255 | ||
256 | /* | |
257 | * This mutex protects dm_bufio_cache_size_latch, | |
258 | * dm_bufio_cache_size_per_client and dm_bufio_client_count | |
259 | */ | |
260 | static DEFINE_MUTEX(dm_bufio_clients_lock); | |
261 | ||
86bad0c7 MP |
262 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
263 | static void buffer_record_stack(struct dm_buffer *b) | |
264 | { | |
265 | b->stack_trace.nr_entries = 0; | |
266 | b->stack_trace.max_entries = MAX_STACK; | |
267 | b->stack_trace.entries = b->stack_entries; | |
268 | b->stack_trace.skip = 2; | |
269 | save_stack_trace(&b->stack_trace); | |
270 | } | |
271 | #endif | |
272 | ||
4e420c45 JT |
273 | /*---------------------------------------------------------------- |
274 | * A red/black tree acts as an index for all the buffers. | |
275 | *--------------------------------------------------------------*/ | |
276 | static struct dm_buffer *__find(struct dm_bufio_client *c, sector_t block) | |
277 | { | |
278 | struct rb_node *n = c->buffer_tree.rb_node; | |
279 | struct dm_buffer *b; | |
280 | ||
281 | while (n) { | |
282 | b = container_of(n, struct dm_buffer, node); | |
283 | ||
284 | if (b->block == block) | |
285 | return b; | |
286 | ||
287 | n = (b->block < block) ? n->rb_left : n->rb_right; | |
288 | } | |
289 | ||
290 | return NULL; | |
291 | } | |
292 | ||
293 | static void __insert(struct dm_bufio_client *c, struct dm_buffer *b) | |
294 | { | |
295 | struct rb_node **new = &c->buffer_tree.rb_node, *parent = NULL; | |
296 | struct dm_buffer *found; | |
297 | ||
298 | while (*new) { | |
299 | found = container_of(*new, struct dm_buffer, node); | |
300 | ||
301 | if (found->block == b->block) { | |
302 | BUG_ON(found != b); | |
303 | return; | |
304 | } | |
305 | ||
306 | parent = *new; | |
307 | new = (found->block < b->block) ? | |
308 | &((*new)->rb_left) : &((*new)->rb_right); | |
309 | } | |
310 | ||
311 | rb_link_node(&b->node, parent, new); | |
312 | rb_insert_color(&b->node, &c->buffer_tree); | |
313 | } | |
314 | ||
315 | static void __remove(struct dm_bufio_client *c, struct dm_buffer *b) | |
316 | { | |
317 | rb_erase(&b->node, &c->buffer_tree); | |
318 | } | |
319 | ||
95d402f0 MP |
320 | /*----------------------------------------------------------------*/ |
321 | ||
322 | static void adjust_total_allocated(enum data_mode data_mode, long diff) | |
323 | { | |
324 | static unsigned long * const class_ptr[DATA_MODE_LIMIT] = { | |
325 | &dm_bufio_allocated_kmem_cache, | |
326 | &dm_bufio_allocated_get_free_pages, | |
327 | &dm_bufio_allocated_vmalloc, | |
328 | }; | |
329 | ||
330 | spin_lock(¶m_spinlock); | |
331 | ||
332 | *class_ptr[data_mode] += diff; | |
333 | ||
334 | dm_bufio_current_allocated += diff; | |
335 | ||
336 | if (dm_bufio_current_allocated > dm_bufio_peak_allocated) | |
337 | dm_bufio_peak_allocated = dm_bufio_current_allocated; | |
338 | ||
339 | spin_unlock(¶m_spinlock); | |
340 | } | |
341 | ||
342 | /* | |
343 | * Change the number of clients and recalculate per-client limit. | |
344 | */ | |
345 | static void __cache_size_refresh(void) | |
346 | { | |
347 | BUG_ON(!mutex_is_locked(&dm_bufio_clients_lock)); | |
348 | BUG_ON(dm_bufio_client_count < 0); | |
349 | ||
fe5fe906 | 350 | dm_bufio_cache_size_latch = ACCESS_ONCE(dm_bufio_cache_size); |
95d402f0 MP |
351 | |
352 | /* | |
353 | * Use default if set to 0 and report the actual cache size used. | |
354 | */ | |
355 | if (!dm_bufio_cache_size_latch) { | |
356 | (void)cmpxchg(&dm_bufio_cache_size, 0, | |
357 | dm_bufio_default_cache_size); | |
358 | dm_bufio_cache_size_latch = dm_bufio_default_cache_size; | |
359 | } | |
360 | ||
361 | dm_bufio_cache_size_per_client = dm_bufio_cache_size_latch / | |
362 | (dm_bufio_client_count ? : 1); | |
363 | } | |
364 | ||
365 | /* | |
366 | * Allocating buffer data. | |
367 | * | |
368 | * Small buffers are allocated with kmem_cache, to use space optimally. | |
369 | * | |
370 | * For large buffers, we choose between get_free_pages and vmalloc. | |
371 | * Each has advantages and disadvantages. | |
372 | * | |
373 | * __get_free_pages can randomly fail if the memory is fragmented. | |
374 | * __vmalloc won't randomly fail, but vmalloc space is limited (it may be | |
375 | * as low as 128M) so using it for caching is not appropriate. | |
376 | * | |
377 | * If the allocation may fail we use __get_free_pages. Memory fragmentation | |
378 | * won't have a fatal effect here, but it just causes flushes of some other | |
379 | * buffers and more I/O will be performed. Don't use __get_free_pages if it | |
380 | * always fails (i.e. order >= MAX_ORDER). | |
381 | * | |
382 | * If the allocation shouldn't fail we use __vmalloc. This is only for the | |
383 | * initial reserve allocation, so there's no risk of wasting all vmalloc | |
384 | * space. | |
385 | */ | |
386 | static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask, | |
387 | enum data_mode *data_mode) | |
388 | { | |
502624bd MP |
389 | unsigned noio_flag; |
390 | void *ptr; | |
391 | ||
95d402f0 MP |
392 | if (c->block_size <= DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT) { |
393 | *data_mode = DATA_MODE_SLAB; | |
394 | return kmem_cache_alloc(DM_BUFIO_CACHE(c), gfp_mask); | |
395 | } | |
396 | ||
397 | if (c->block_size <= DM_BUFIO_BLOCK_SIZE_GFP_LIMIT && | |
398 | gfp_mask & __GFP_NORETRY) { | |
399 | *data_mode = DATA_MODE_GET_FREE_PAGES; | |
400 | return (void *)__get_free_pages(gfp_mask, | |
401 | c->pages_per_block_bits); | |
402 | } | |
403 | ||
404 | *data_mode = DATA_MODE_VMALLOC; | |
502624bd MP |
405 | |
406 | /* | |
407 | * __vmalloc allocates the data pages and auxiliary structures with | |
408 | * gfp_flags that were specified, but pagetables are always allocated | |
409 | * with GFP_KERNEL, no matter what was specified as gfp_mask. | |
410 | * | |
411 | * Consequently, we must set per-process flag PF_MEMALLOC_NOIO so that | |
412 | * all allocations done by this process (including pagetables) are done | |
413 | * as if GFP_NOIO was specified. | |
414 | */ | |
415 | ||
416 | if (gfp_mask & __GFP_NORETRY) | |
417 | noio_flag = memalloc_noio_save(); | |
418 | ||
220cd058 | 419 | ptr = __vmalloc(c->block_size, gfp_mask | __GFP_HIGHMEM, PAGE_KERNEL); |
502624bd MP |
420 | |
421 | if (gfp_mask & __GFP_NORETRY) | |
422 | memalloc_noio_restore(noio_flag); | |
423 | ||
424 | return ptr; | |
95d402f0 MP |
425 | } |
426 | ||
427 | /* | |
428 | * Free buffer's data. | |
429 | */ | |
430 | static void free_buffer_data(struct dm_bufio_client *c, | |
431 | void *data, enum data_mode data_mode) | |
432 | { | |
433 | switch (data_mode) { | |
434 | case DATA_MODE_SLAB: | |
435 | kmem_cache_free(DM_BUFIO_CACHE(c), data); | |
436 | break; | |
437 | ||
438 | case DATA_MODE_GET_FREE_PAGES: | |
439 | free_pages((unsigned long)data, c->pages_per_block_bits); | |
440 | break; | |
441 | ||
442 | case DATA_MODE_VMALLOC: | |
443 | vfree(data); | |
444 | break; | |
445 | ||
446 | default: | |
447 | DMCRIT("dm_bufio_free_buffer_data: bad data mode: %d", | |
448 | data_mode); | |
449 | BUG(); | |
450 | } | |
451 | } | |
452 | ||
453 | /* | |
454 | * Allocate buffer and its data. | |
455 | */ | |
456 | static struct dm_buffer *alloc_buffer(struct dm_bufio_client *c, gfp_t gfp_mask) | |
457 | { | |
458 | struct dm_buffer *b = kmalloc(sizeof(struct dm_buffer) + c->aux_size, | |
459 | gfp_mask); | |
460 | ||
461 | if (!b) | |
462 | return NULL; | |
463 | ||
464 | b->c = c; | |
465 | ||
466 | b->data = alloc_buffer_data(c, gfp_mask, &b->data_mode); | |
467 | if (!b->data) { | |
468 | kfree(b); | |
469 | return NULL; | |
470 | } | |
471 | ||
472 | adjust_total_allocated(b->data_mode, (long)c->block_size); | |
473 | ||
86bad0c7 MP |
474 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
475 | memset(&b->stack_trace, 0, sizeof(b->stack_trace)); | |
476 | #endif | |
95d402f0 MP |
477 | return b; |
478 | } | |
479 | ||
480 | /* | |
481 | * Free buffer and its data. | |
482 | */ | |
483 | static void free_buffer(struct dm_buffer *b) | |
484 | { | |
485 | struct dm_bufio_client *c = b->c; | |
486 | ||
487 | adjust_total_allocated(b->data_mode, -(long)c->block_size); | |
488 | ||
489 | free_buffer_data(c, b->data, b->data_mode); | |
490 | kfree(b); | |
491 | } | |
492 | ||
493 | /* | |
494 | * Link buffer to the hash list and clean or dirty queue. | |
495 | */ | |
496 | static void __link_buffer(struct dm_buffer *b, sector_t block, int dirty) | |
497 | { | |
498 | struct dm_bufio_client *c = b->c; | |
499 | ||
500 | c->n_buffers[dirty]++; | |
501 | b->block = block; | |
502 | b->list_mode = dirty; | |
503 | list_add(&b->lru_list, &c->lru[dirty]); | |
4e420c45 | 504 | __insert(b->c, b); |
95d402f0 MP |
505 | b->last_accessed = jiffies; |
506 | } | |
507 | ||
508 | /* | |
509 | * Unlink buffer from the hash list and dirty or clean queue. | |
510 | */ | |
511 | static void __unlink_buffer(struct dm_buffer *b) | |
512 | { | |
513 | struct dm_bufio_client *c = b->c; | |
514 | ||
515 | BUG_ON(!c->n_buffers[b->list_mode]); | |
516 | ||
517 | c->n_buffers[b->list_mode]--; | |
4e420c45 | 518 | __remove(b->c, b); |
95d402f0 MP |
519 | list_del(&b->lru_list); |
520 | } | |
521 | ||
522 | /* | |
523 | * Place the buffer to the head of dirty or clean LRU queue. | |
524 | */ | |
525 | static void __relink_lru(struct dm_buffer *b, int dirty) | |
526 | { | |
527 | struct dm_bufio_client *c = b->c; | |
528 | ||
529 | BUG_ON(!c->n_buffers[b->list_mode]); | |
530 | ||
531 | c->n_buffers[b->list_mode]--; | |
532 | c->n_buffers[dirty]++; | |
533 | b->list_mode = dirty; | |
54499afb | 534 | list_move(&b->lru_list, &c->lru[dirty]); |
eb76faf5 | 535 | b->last_accessed = jiffies; |
95d402f0 MP |
536 | } |
537 | ||
538 | /*---------------------------------------------------------------- | |
539 | * Submit I/O on the buffer. | |
540 | * | |
541 | * Bio interface is faster but it has some problems: | |
542 | * the vector list is limited (increasing this limit increases | |
543 | * memory-consumption per buffer, so it is not viable); | |
544 | * | |
545 | * the memory must be direct-mapped, not vmalloced; | |
546 | * | |
547 | * the I/O driver can reject requests spuriously if it thinks that | |
548 | * the requests are too big for the device or if they cross a | |
549 | * controller-defined memory boundary. | |
550 | * | |
551 | * If the buffer is small enough (up to DM_BUFIO_INLINE_VECS pages) and | |
552 | * it is not vmalloced, try using the bio interface. | |
553 | * | |
554 | * If the buffer is big, if it is vmalloced or if the underlying device | |
555 | * rejects the bio because it is too large, use dm-io layer to do the I/O. | |
556 | * The dm-io layer splits the I/O into multiple requests, avoiding the above | |
557 | * shortcomings. | |
558 | *--------------------------------------------------------------*/ | |
559 | ||
560 | /* | |
561 | * dm-io completion routine. It just calls b->bio.bi_end_io, pretending | |
562 | * that the request was handled directly with bio interface. | |
563 | */ | |
564 | static void dmio_complete(unsigned long error, void *context) | |
565 | { | |
566 | struct dm_buffer *b = context; | |
567 | ||
4246a0b6 CH |
568 | b->bio.bi_error = error ? -EIO : 0; |
569 | b->bio.bi_end_io(&b->bio); | |
95d402f0 MP |
570 | } |
571 | ||
572 | static void use_dmio(struct dm_buffer *b, int rw, sector_t block, | |
573 | bio_end_io_t *end_io) | |
574 | { | |
575 | int r; | |
576 | struct dm_io_request io_req = { | |
577 | .bi_rw = rw, | |
578 | .notify.fn = dmio_complete, | |
579 | .notify.context = b, | |
580 | .client = b->c->dm_io, | |
581 | }; | |
582 | struct dm_io_region region = { | |
583 | .bdev = b->c->bdev, | |
584 | .sector = block << b->c->sectors_per_block_bits, | |
585 | .count = b->c->block_size >> SECTOR_SHIFT, | |
586 | }; | |
587 | ||
588 | if (b->data_mode != DATA_MODE_VMALLOC) { | |
589 | io_req.mem.type = DM_IO_KMEM; | |
590 | io_req.mem.ptr.addr = b->data; | |
591 | } else { | |
592 | io_req.mem.type = DM_IO_VMA; | |
593 | io_req.mem.ptr.vma = b->data; | |
594 | } | |
595 | ||
596 | b->bio.bi_end_io = end_io; | |
597 | ||
598 | r = dm_io(&io_req, 1, ®ion, NULL); | |
4246a0b6 CH |
599 | if (r) { |
600 | b->bio.bi_error = r; | |
601 | end_io(&b->bio); | |
602 | } | |
95d402f0 MP |
603 | } |
604 | ||
4246a0b6 | 605 | static void inline_endio(struct bio *bio) |
445559cd DW |
606 | { |
607 | bio_end_io_t *end_fn = bio->bi_private; | |
4246a0b6 | 608 | int error = bio->bi_error; |
445559cd DW |
609 | |
610 | /* | |
611 | * Reset the bio to free any attached resources | |
612 | * (e.g. bio integrity profiles). | |
613 | */ | |
614 | bio_reset(bio); | |
615 | ||
4246a0b6 CH |
616 | bio->bi_error = error; |
617 | end_fn(bio); | |
445559cd DW |
618 | } |
619 | ||
95d402f0 MP |
620 | static void use_inline_bio(struct dm_buffer *b, int rw, sector_t block, |
621 | bio_end_io_t *end_io) | |
622 | { | |
623 | char *ptr; | |
624 | int len; | |
625 | ||
626 | bio_init(&b->bio); | |
627 | b->bio.bi_io_vec = b->bio_vec; | |
628 | b->bio.bi_max_vecs = DM_BUFIO_INLINE_VECS; | |
4f024f37 | 629 | b->bio.bi_iter.bi_sector = block << b->c->sectors_per_block_bits; |
95d402f0 | 630 | b->bio.bi_bdev = b->c->bdev; |
445559cd DW |
631 | b->bio.bi_end_io = inline_endio; |
632 | /* | |
633 | * Use of .bi_private isn't a problem here because | |
634 | * the dm_buffer's inline bio is local to bufio. | |
635 | */ | |
636 | b->bio.bi_private = end_io; | |
95d402f0 MP |
637 | |
638 | /* | |
639 | * We assume that if len >= PAGE_SIZE ptr is page-aligned. | |
640 | * If len < PAGE_SIZE the buffer doesn't cross page boundary. | |
641 | */ | |
642 | ptr = b->data; | |
643 | len = b->c->block_size; | |
644 | ||
645 | if (len >= PAGE_SIZE) | |
646 | BUG_ON((unsigned long)ptr & (PAGE_SIZE - 1)); | |
647 | else | |
648 | BUG_ON((unsigned long)ptr & (len - 1)); | |
649 | ||
650 | do { | |
651 | if (!bio_add_page(&b->bio, virt_to_page(ptr), | |
652 | len < PAGE_SIZE ? len : PAGE_SIZE, | |
756d097b | 653 | offset_in_page(ptr))) { |
95d402f0 MP |
654 | BUG_ON(b->c->block_size <= PAGE_SIZE); |
655 | use_dmio(b, rw, block, end_io); | |
656 | return; | |
657 | } | |
658 | ||
659 | len -= PAGE_SIZE; | |
660 | ptr += PAGE_SIZE; | |
661 | } while (len > 0); | |
662 | ||
663 | submit_bio(rw, &b->bio); | |
664 | } | |
665 | ||
666 | static void submit_io(struct dm_buffer *b, int rw, sector_t block, | |
667 | bio_end_io_t *end_io) | |
668 | { | |
669 | if (rw == WRITE && b->c->write_callback) | |
670 | b->c->write_callback(b); | |
671 | ||
672 | if (b->c->block_size <= DM_BUFIO_INLINE_VECS * PAGE_SIZE && | |
673 | b->data_mode != DATA_MODE_VMALLOC) | |
674 | use_inline_bio(b, rw, block, end_io); | |
675 | else | |
676 | use_dmio(b, rw, block, end_io); | |
677 | } | |
678 | ||
679 | /*---------------------------------------------------------------- | |
680 | * Writing dirty buffers | |
681 | *--------------------------------------------------------------*/ | |
682 | ||
683 | /* | |
684 | * The endio routine for write. | |
685 | * | |
686 | * Set the error, clear B_WRITING bit and wake anyone who was waiting on | |
687 | * it. | |
688 | */ | |
4246a0b6 | 689 | static void write_endio(struct bio *bio) |
95d402f0 MP |
690 | { |
691 | struct dm_buffer *b = container_of(bio, struct dm_buffer, bio); | |
692 | ||
4246a0b6 CH |
693 | b->write_error = bio->bi_error; |
694 | if (unlikely(bio->bi_error)) { | |
95d402f0 | 695 | struct dm_bufio_client *c = b->c; |
4246a0b6 | 696 | int error = bio->bi_error; |
95d402f0 MP |
697 | (void)cmpxchg(&c->async_write_error, 0, error); |
698 | } | |
699 | ||
700 | BUG_ON(!test_bit(B_WRITING, &b->state)); | |
701 | ||
4e857c58 | 702 | smp_mb__before_atomic(); |
95d402f0 | 703 | clear_bit(B_WRITING, &b->state); |
4e857c58 | 704 | smp_mb__after_atomic(); |
95d402f0 MP |
705 | |
706 | wake_up_bit(&b->state, B_WRITING); | |
707 | } | |
708 | ||
95d402f0 MP |
709 | /* |
710 | * Initiate a write on a dirty buffer, but don't wait for it. | |
711 | * | |
712 | * - If the buffer is not dirty, exit. | |
713 | * - If there some previous write going on, wait for it to finish (we can't | |
714 | * have two writes on the same buffer simultaneously). | |
715 | * - Submit our write and don't wait on it. We set B_WRITING indicating | |
716 | * that there is a write in progress. | |
717 | */ | |
2480945c MP |
718 | static void __write_dirty_buffer(struct dm_buffer *b, |
719 | struct list_head *write_list) | |
95d402f0 MP |
720 | { |
721 | if (!test_bit(B_DIRTY, &b->state)) | |
722 | return; | |
723 | ||
724 | clear_bit(B_DIRTY, &b->state); | |
74316201 | 725 | wait_on_bit_lock_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE); |
95d402f0 | 726 | |
2480945c MP |
727 | if (!write_list) |
728 | submit_io(b, WRITE, b->block, write_endio); | |
729 | else | |
730 | list_add_tail(&b->write_list, write_list); | |
731 | } | |
732 | ||
733 | static void __flush_write_list(struct list_head *write_list) | |
734 | { | |
735 | struct blk_plug plug; | |
736 | blk_start_plug(&plug); | |
737 | while (!list_empty(write_list)) { | |
738 | struct dm_buffer *b = | |
739 | list_entry(write_list->next, struct dm_buffer, write_list); | |
740 | list_del(&b->write_list); | |
741 | submit_io(b, WRITE, b->block, write_endio); | |
742 | dm_bufio_cond_resched(); | |
743 | } | |
744 | blk_finish_plug(&plug); | |
95d402f0 MP |
745 | } |
746 | ||
747 | /* | |
748 | * Wait until any activity on the buffer finishes. Possibly write the | |
749 | * buffer if it is dirty. When this function finishes, there is no I/O | |
750 | * running on the buffer and the buffer is not dirty. | |
751 | */ | |
752 | static void __make_buffer_clean(struct dm_buffer *b) | |
753 | { | |
754 | BUG_ON(b->hold_count); | |
755 | ||
756 | if (!b->state) /* fast case */ | |
757 | return; | |
758 | ||
74316201 | 759 | wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE); |
2480945c | 760 | __write_dirty_buffer(b, NULL); |
74316201 | 761 | wait_on_bit_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE); |
95d402f0 MP |
762 | } |
763 | ||
764 | /* | |
765 | * Find some buffer that is not held by anybody, clean it, unlink it and | |
766 | * return it. | |
767 | */ | |
768 | static struct dm_buffer *__get_unclaimed_buffer(struct dm_bufio_client *c) | |
769 | { | |
770 | struct dm_buffer *b; | |
771 | ||
772 | list_for_each_entry_reverse(b, &c->lru[LIST_CLEAN], lru_list) { | |
773 | BUG_ON(test_bit(B_WRITING, &b->state)); | |
774 | BUG_ON(test_bit(B_DIRTY, &b->state)); | |
775 | ||
776 | if (!b->hold_count) { | |
777 | __make_buffer_clean(b); | |
778 | __unlink_buffer(b); | |
779 | return b; | |
780 | } | |
781 | dm_bufio_cond_resched(); | |
782 | } | |
783 | ||
784 | list_for_each_entry_reverse(b, &c->lru[LIST_DIRTY], lru_list) { | |
785 | BUG_ON(test_bit(B_READING, &b->state)); | |
786 | ||
787 | if (!b->hold_count) { | |
788 | __make_buffer_clean(b); | |
789 | __unlink_buffer(b); | |
790 | return b; | |
791 | } | |
792 | dm_bufio_cond_resched(); | |
793 | } | |
794 | ||
795 | return NULL; | |
796 | } | |
797 | ||
798 | /* | |
799 | * Wait until some other threads free some buffer or release hold count on | |
800 | * some buffer. | |
801 | * | |
802 | * This function is entered with c->lock held, drops it and regains it | |
803 | * before exiting. | |
804 | */ | |
805 | static void __wait_for_free_buffer(struct dm_bufio_client *c) | |
806 | { | |
807 | DECLARE_WAITQUEUE(wait, current); | |
808 | ||
809 | add_wait_queue(&c->free_buffer_wait, &wait); | |
810 | set_task_state(current, TASK_UNINTERRUPTIBLE); | |
811 | dm_bufio_unlock(c); | |
812 | ||
813 | io_schedule(); | |
814 | ||
95d402f0 MP |
815 | remove_wait_queue(&c->free_buffer_wait, &wait); |
816 | ||
817 | dm_bufio_lock(c); | |
818 | } | |
819 | ||
a66cc28f MP |
820 | enum new_flag { |
821 | NF_FRESH = 0, | |
822 | NF_READ = 1, | |
823 | NF_GET = 2, | |
824 | NF_PREFETCH = 3 | |
825 | }; | |
826 | ||
95d402f0 MP |
827 | /* |
828 | * Allocate a new buffer. If the allocation is not possible, wait until | |
829 | * some other thread frees a buffer. | |
830 | * | |
831 | * May drop the lock and regain it. | |
832 | */ | |
a66cc28f | 833 | static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client *c, enum new_flag nf) |
95d402f0 MP |
834 | { |
835 | struct dm_buffer *b; | |
836 | ||
837 | /* | |
838 | * dm-bufio is resistant to allocation failures (it just keeps | |
839 | * one buffer reserved in cases all the allocations fail). | |
840 | * So set flags to not try too hard: | |
841 | * GFP_NOIO: don't recurse into the I/O layer | |
842 | * __GFP_NORETRY: don't retry and rather return failure | |
843 | * __GFP_NOMEMALLOC: don't use emergency reserves | |
844 | * __GFP_NOWARN: don't print a warning in case of failure | |
845 | * | |
846 | * For debugging, if we set the cache size to 1, no new buffers will | |
847 | * be allocated. | |
848 | */ | |
849 | while (1) { | |
850 | if (dm_bufio_cache_size_latch != 1) { | |
851 | b = alloc_buffer(c, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); | |
852 | if (b) | |
853 | return b; | |
854 | } | |
855 | ||
a66cc28f MP |
856 | if (nf == NF_PREFETCH) |
857 | return NULL; | |
858 | ||
95d402f0 MP |
859 | if (!list_empty(&c->reserved_buffers)) { |
860 | b = list_entry(c->reserved_buffers.next, | |
861 | struct dm_buffer, lru_list); | |
862 | list_del(&b->lru_list); | |
863 | c->need_reserved_buffers++; | |
864 | ||
865 | return b; | |
866 | } | |
867 | ||
868 | b = __get_unclaimed_buffer(c); | |
869 | if (b) | |
870 | return b; | |
871 | ||
872 | __wait_for_free_buffer(c); | |
873 | } | |
874 | } | |
875 | ||
a66cc28f | 876 | static struct dm_buffer *__alloc_buffer_wait(struct dm_bufio_client *c, enum new_flag nf) |
95d402f0 | 877 | { |
a66cc28f MP |
878 | struct dm_buffer *b = __alloc_buffer_wait_no_callback(c, nf); |
879 | ||
880 | if (!b) | |
881 | return NULL; | |
95d402f0 MP |
882 | |
883 | if (c->alloc_callback) | |
884 | c->alloc_callback(b); | |
885 | ||
886 | return b; | |
887 | } | |
888 | ||
889 | /* | |
890 | * Free a buffer and wake other threads waiting for free buffers. | |
891 | */ | |
892 | static void __free_buffer_wake(struct dm_buffer *b) | |
893 | { | |
894 | struct dm_bufio_client *c = b->c; | |
895 | ||
896 | if (!c->need_reserved_buffers) | |
897 | free_buffer(b); | |
898 | else { | |
899 | list_add(&b->lru_list, &c->reserved_buffers); | |
900 | c->need_reserved_buffers--; | |
901 | } | |
902 | ||
903 | wake_up(&c->free_buffer_wait); | |
904 | } | |
905 | ||
2480945c MP |
906 | static void __write_dirty_buffers_async(struct dm_bufio_client *c, int no_wait, |
907 | struct list_head *write_list) | |
95d402f0 MP |
908 | { |
909 | struct dm_buffer *b, *tmp; | |
910 | ||
911 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { | |
912 | BUG_ON(test_bit(B_READING, &b->state)); | |
913 | ||
914 | if (!test_bit(B_DIRTY, &b->state) && | |
915 | !test_bit(B_WRITING, &b->state)) { | |
916 | __relink_lru(b, LIST_CLEAN); | |
917 | continue; | |
918 | } | |
919 | ||
920 | if (no_wait && test_bit(B_WRITING, &b->state)) | |
921 | return; | |
922 | ||
2480945c | 923 | __write_dirty_buffer(b, write_list); |
95d402f0 MP |
924 | dm_bufio_cond_resched(); |
925 | } | |
926 | } | |
927 | ||
928 | /* | |
929 | * Get writeback threshold and buffer limit for a given client. | |
930 | */ | |
931 | static void __get_memory_limit(struct dm_bufio_client *c, | |
932 | unsigned long *threshold_buffers, | |
933 | unsigned long *limit_buffers) | |
934 | { | |
935 | unsigned long buffers; | |
936 | ||
fe5fe906 | 937 | if (ACCESS_ONCE(dm_bufio_cache_size) != dm_bufio_cache_size_latch) { |
95d402f0 MP |
938 | mutex_lock(&dm_bufio_clients_lock); |
939 | __cache_size_refresh(); | |
940 | mutex_unlock(&dm_bufio_clients_lock); | |
941 | } | |
942 | ||
943 | buffers = dm_bufio_cache_size_per_client >> | |
944 | (c->sectors_per_block_bits + SECTOR_SHIFT); | |
945 | ||
55b082e6 MP |
946 | if (buffers < c->minimum_buffers) |
947 | buffers = c->minimum_buffers; | |
95d402f0 MP |
948 | |
949 | *limit_buffers = buffers; | |
950 | *threshold_buffers = buffers * DM_BUFIO_WRITEBACK_PERCENT / 100; | |
951 | } | |
952 | ||
953 | /* | |
954 | * Check if we're over watermark. | |
955 | * If we are over threshold_buffers, start freeing buffers. | |
956 | * If we're over "limit_buffers", block until we get under the limit. | |
957 | */ | |
2480945c MP |
958 | static void __check_watermark(struct dm_bufio_client *c, |
959 | struct list_head *write_list) | |
95d402f0 MP |
960 | { |
961 | unsigned long threshold_buffers, limit_buffers; | |
962 | ||
963 | __get_memory_limit(c, &threshold_buffers, &limit_buffers); | |
964 | ||
965 | while (c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY] > | |
966 | limit_buffers) { | |
967 | ||
968 | struct dm_buffer *b = __get_unclaimed_buffer(c); | |
969 | ||
970 | if (!b) | |
971 | return; | |
972 | ||
973 | __free_buffer_wake(b); | |
974 | dm_bufio_cond_resched(); | |
975 | } | |
976 | ||
977 | if (c->n_buffers[LIST_DIRTY] > threshold_buffers) | |
2480945c | 978 | __write_dirty_buffers_async(c, 1, write_list); |
95d402f0 MP |
979 | } |
980 | ||
95d402f0 MP |
981 | /*---------------------------------------------------------------- |
982 | * Getting a buffer | |
983 | *--------------------------------------------------------------*/ | |
984 | ||
95d402f0 | 985 | static struct dm_buffer *__bufio_new(struct dm_bufio_client *c, sector_t block, |
2480945c MP |
986 | enum new_flag nf, int *need_submit, |
987 | struct list_head *write_list) | |
95d402f0 MP |
988 | { |
989 | struct dm_buffer *b, *new_b = NULL; | |
990 | ||
991 | *need_submit = 0; | |
992 | ||
993 | b = __find(c, block); | |
a66cc28f MP |
994 | if (b) |
995 | goto found_buffer; | |
95d402f0 MP |
996 | |
997 | if (nf == NF_GET) | |
998 | return NULL; | |
999 | ||
a66cc28f MP |
1000 | new_b = __alloc_buffer_wait(c, nf); |
1001 | if (!new_b) | |
1002 | return NULL; | |
95d402f0 MP |
1003 | |
1004 | /* | |
1005 | * We've had a period where the mutex was unlocked, so need to | |
1006 | * recheck the hash table. | |
1007 | */ | |
1008 | b = __find(c, block); | |
1009 | if (b) { | |
1010 | __free_buffer_wake(new_b); | |
a66cc28f | 1011 | goto found_buffer; |
95d402f0 MP |
1012 | } |
1013 | ||
2480945c | 1014 | __check_watermark(c, write_list); |
95d402f0 MP |
1015 | |
1016 | b = new_b; | |
1017 | b->hold_count = 1; | |
1018 | b->read_error = 0; | |
1019 | b->write_error = 0; | |
1020 | __link_buffer(b, block, LIST_CLEAN); | |
1021 | ||
1022 | if (nf == NF_FRESH) { | |
1023 | b->state = 0; | |
1024 | return b; | |
1025 | } | |
1026 | ||
1027 | b->state = 1 << B_READING; | |
1028 | *need_submit = 1; | |
1029 | ||
1030 | return b; | |
a66cc28f MP |
1031 | |
1032 | found_buffer: | |
1033 | if (nf == NF_PREFETCH) | |
1034 | return NULL; | |
1035 | /* | |
1036 | * Note: it is essential that we don't wait for the buffer to be | |
1037 | * read if dm_bufio_get function is used. Both dm_bufio_get and | |
1038 | * dm_bufio_prefetch can be used in the driver request routine. | |
1039 | * If the user called both dm_bufio_prefetch and dm_bufio_get on | |
1040 | * the same buffer, it would deadlock if we waited. | |
1041 | */ | |
1042 | if (nf == NF_GET && unlikely(test_bit(B_READING, &b->state))) | |
1043 | return NULL; | |
1044 | ||
1045 | b->hold_count++; | |
1046 | __relink_lru(b, test_bit(B_DIRTY, &b->state) || | |
1047 | test_bit(B_WRITING, &b->state)); | |
1048 | return b; | |
95d402f0 MP |
1049 | } |
1050 | ||
1051 | /* | |
1052 | * The endio routine for reading: set the error, clear the bit and wake up | |
1053 | * anyone waiting on the buffer. | |
1054 | */ | |
4246a0b6 | 1055 | static void read_endio(struct bio *bio) |
95d402f0 MP |
1056 | { |
1057 | struct dm_buffer *b = container_of(bio, struct dm_buffer, bio); | |
1058 | ||
4246a0b6 | 1059 | b->read_error = bio->bi_error; |
95d402f0 MP |
1060 | |
1061 | BUG_ON(!test_bit(B_READING, &b->state)); | |
1062 | ||
4e857c58 | 1063 | smp_mb__before_atomic(); |
95d402f0 | 1064 | clear_bit(B_READING, &b->state); |
4e857c58 | 1065 | smp_mb__after_atomic(); |
95d402f0 MP |
1066 | |
1067 | wake_up_bit(&b->state, B_READING); | |
1068 | } | |
1069 | ||
1070 | /* | |
1071 | * A common routine for dm_bufio_new and dm_bufio_read. Operation of these | |
1072 | * functions is similar except that dm_bufio_new doesn't read the | |
1073 | * buffer from the disk (assuming that the caller overwrites all the data | |
1074 | * and uses dm_bufio_mark_buffer_dirty to write new data back). | |
1075 | */ | |
1076 | static void *new_read(struct dm_bufio_client *c, sector_t block, | |
1077 | enum new_flag nf, struct dm_buffer **bp) | |
1078 | { | |
1079 | int need_submit; | |
1080 | struct dm_buffer *b; | |
1081 | ||
2480945c MP |
1082 | LIST_HEAD(write_list); |
1083 | ||
95d402f0 | 1084 | dm_bufio_lock(c); |
2480945c | 1085 | b = __bufio_new(c, block, nf, &need_submit, &write_list); |
86bad0c7 MP |
1086 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
1087 | if (b && b->hold_count == 1) | |
1088 | buffer_record_stack(b); | |
1089 | #endif | |
95d402f0 MP |
1090 | dm_bufio_unlock(c); |
1091 | ||
2480945c MP |
1092 | __flush_write_list(&write_list); |
1093 | ||
a66cc28f | 1094 | if (!b) |
f98c8f79 | 1095 | return NULL; |
95d402f0 MP |
1096 | |
1097 | if (need_submit) | |
1098 | submit_io(b, READ, b->block, read_endio); | |
1099 | ||
74316201 | 1100 | wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE); |
95d402f0 MP |
1101 | |
1102 | if (b->read_error) { | |
1103 | int error = b->read_error; | |
1104 | ||
1105 | dm_bufio_release(b); | |
1106 | ||
1107 | return ERR_PTR(error); | |
1108 | } | |
1109 | ||
1110 | *bp = b; | |
1111 | ||
1112 | return b->data; | |
1113 | } | |
1114 | ||
1115 | void *dm_bufio_get(struct dm_bufio_client *c, sector_t block, | |
1116 | struct dm_buffer **bp) | |
1117 | { | |
1118 | return new_read(c, block, NF_GET, bp); | |
1119 | } | |
1120 | EXPORT_SYMBOL_GPL(dm_bufio_get); | |
1121 | ||
1122 | void *dm_bufio_read(struct dm_bufio_client *c, sector_t block, | |
1123 | struct dm_buffer **bp) | |
1124 | { | |
1125 | BUG_ON(dm_bufio_in_request()); | |
1126 | ||
1127 | return new_read(c, block, NF_READ, bp); | |
1128 | } | |
1129 | EXPORT_SYMBOL_GPL(dm_bufio_read); | |
1130 | ||
1131 | void *dm_bufio_new(struct dm_bufio_client *c, sector_t block, | |
1132 | struct dm_buffer **bp) | |
1133 | { | |
1134 | BUG_ON(dm_bufio_in_request()); | |
1135 | ||
1136 | return new_read(c, block, NF_FRESH, bp); | |
1137 | } | |
1138 | EXPORT_SYMBOL_GPL(dm_bufio_new); | |
1139 | ||
a66cc28f MP |
1140 | void dm_bufio_prefetch(struct dm_bufio_client *c, |
1141 | sector_t block, unsigned n_blocks) | |
1142 | { | |
1143 | struct blk_plug plug; | |
1144 | ||
2480945c MP |
1145 | LIST_HEAD(write_list); |
1146 | ||
3b6b7813 MP |
1147 | BUG_ON(dm_bufio_in_request()); |
1148 | ||
a66cc28f MP |
1149 | blk_start_plug(&plug); |
1150 | dm_bufio_lock(c); | |
1151 | ||
1152 | for (; n_blocks--; block++) { | |
1153 | int need_submit; | |
1154 | struct dm_buffer *b; | |
2480945c MP |
1155 | b = __bufio_new(c, block, NF_PREFETCH, &need_submit, |
1156 | &write_list); | |
1157 | if (unlikely(!list_empty(&write_list))) { | |
1158 | dm_bufio_unlock(c); | |
1159 | blk_finish_plug(&plug); | |
1160 | __flush_write_list(&write_list); | |
1161 | blk_start_plug(&plug); | |
1162 | dm_bufio_lock(c); | |
1163 | } | |
a66cc28f MP |
1164 | if (unlikely(b != NULL)) { |
1165 | dm_bufio_unlock(c); | |
1166 | ||
1167 | if (need_submit) | |
1168 | submit_io(b, READ, b->block, read_endio); | |
1169 | dm_bufio_release(b); | |
1170 | ||
1171 | dm_bufio_cond_resched(); | |
1172 | ||
1173 | if (!n_blocks) | |
1174 | goto flush_plug; | |
1175 | dm_bufio_lock(c); | |
1176 | } | |
a66cc28f MP |
1177 | } |
1178 | ||
1179 | dm_bufio_unlock(c); | |
1180 | ||
1181 | flush_plug: | |
1182 | blk_finish_plug(&plug); | |
1183 | } | |
1184 | EXPORT_SYMBOL_GPL(dm_bufio_prefetch); | |
1185 | ||
95d402f0 MP |
1186 | void dm_bufio_release(struct dm_buffer *b) |
1187 | { | |
1188 | struct dm_bufio_client *c = b->c; | |
1189 | ||
1190 | dm_bufio_lock(c); | |
1191 | ||
95d402f0 MP |
1192 | BUG_ON(!b->hold_count); |
1193 | ||
1194 | b->hold_count--; | |
1195 | if (!b->hold_count) { | |
1196 | wake_up(&c->free_buffer_wait); | |
1197 | ||
1198 | /* | |
1199 | * If there were errors on the buffer, and the buffer is not | |
1200 | * to be written, free the buffer. There is no point in caching | |
1201 | * invalid buffer. | |
1202 | */ | |
1203 | if ((b->read_error || b->write_error) && | |
a66cc28f | 1204 | !test_bit(B_READING, &b->state) && |
95d402f0 MP |
1205 | !test_bit(B_WRITING, &b->state) && |
1206 | !test_bit(B_DIRTY, &b->state)) { | |
1207 | __unlink_buffer(b); | |
1208 | __free_buffer_wake(b); | |
1209 | } | |
1210 | } | |
1211 | ||
1212 | dm_bufio_unlock(c); | |
1213 | } | |
1214 | EXPORT_SYMBOL_GPL(dm_bufio_release); | |
1215 | ||
1216 | void dm_bufio_mark_buffer_dirty(struct dm_buffer *b) | |
1217 | { | |
1218 | struct dm_bufio_client *c = b->c; | |
1219 | ||
1220 | dm_bufio_lock(c); | |
1221 | ||
a66cc28f MP |
1222 | BUG_ON(test_bit(B_READING, &b->state)); |
1223 | ||
95d402f0 MP |
1224 | if (!test_and_set_bit(B_DIRTY, &b->state)) |
1225 | __relink_lru(b, LIST_DIRTY); | |
1226 | ||
1227 | dm_bufio_unlock(c); | |
1228 | } | |
1229 | EXPORT_SYMBOL_GPL(dm_bufio_mark_buffer_dirty); | |
1230 | ||
1231 | void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c) | |
1232 | { | |
2480945c MP |
1233 | LIST_HEAD(write_list); |
1234 | ||
95d402f0 MP |
1235 | BUG_ON(dm_bufio_in_request()); |
1236 | ||
1237 | dm_bufio_lock(c); | |
2480945c | 1238 | __write_dirty_buffers_async(c, 0, &write_list); |
95d402f0 | 1239 | dm_bufio_unlock(c); |
2480945c | 1240 | __flush_write_list(&write_list); |
95d402f0 MP |
1241 | } |
1242 | EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers_async); | |
1243 | ||
1244 | /* | |
1245 | * For performance, it is essential that the buffers are written asynchronously | |
1246 | * and simultaneously (so that the block layer can merge the writes) and then | |
1247 | * waited upon. | |
1248 | * | |
1249 | * Finally, we flush hardware disk cache. | |
1250 | */ | |
1251 | int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c) | |
1252 | { | |
1253 | int a, f; | |
1254 | unsigned long buffers_processed = 0; | |
1255 | struct dm_buffer *b, *tmp; | |
1256 | ||
2480945c MP |
1257 | LIST_HEAD(write_list); |
1258 | ||
1259 | dm_bufio_lock(c); | |
1260 | __write_dirty_buffers_async(c, 0, &write_list); | |
1261 | dm_bufio_unlock(c); | |
1262 | __flush_write_list(&write_list); | |
95d402f0 | 1263 | dm_bufio_lock(c); |
95d402f0 MP |
1264 | |
1265 | again: | |
1266 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { | |
1267 | int dropped_lock = 0; | |
1268 | ||
1269 | if (buffers_processed < c->n_buffers[LIST_DIRTY]) | |
1270 | buffers_processed++; | |
1271 | ||
1272 | BUG_ON(test_bit(B_READING, &b->state)); | |
1273 | ||
1274 | if (test_bit(B_WRITING, &b->state)) { | |
1275 | if (buffers_processed < c->n_buffers[LIST_DIRTY]) { | |
1276 | dropped_lock = 1; | |
1277 | b->hold_count++; | |
1278 | dm_bufio_unlock(c); | |
74316201 N |
1279 | wait_on_bit_io(&b->state, B_WRITING, |
1280 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1281 | dm_bufio_lock(c); |
1282 | b->hold_count--; | |
1283 | } else | |
74316201 N |
1284 | wait_on_bit_io(&b->state, B_WRITING, |
1285 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1286 | } |
1287 | ||
1288 | if (!test_bit(B_DIRTY, &b->state) && | |
1289 | !test_bit(B_WRITING, &b->state)) | |
1290 | __relink_lru(b, LIST_CLEAN); | |
1291 | ||
1292 | dm_bufio_cond_resched(); | |
1293 | ||
1294 | /* | |
1295 | * If we dropped the lock, the list is no longer consistent, | |
1296 | * so we must restart the search. | |
1297 | * | |
1298 | * In the most common case, the buffer just processed is | |
1299 | * relinked to the clean list, so we won't loop scanning the | |
1300 | * same buffer again and again. | |
1301 | * | |
1302 | * This may livelock if there is another thread simultaneously | |
1303 | * dirtying buffers, so we count the number of buffers walked | |
1304 | * and if it exceeds the total number of buffers, it means that | |
1305 | * someone is doing some writes simultaneously with us. In | |
1306 | * this case, stop, dropping the lock. | |
1307 | */ | |
1308 | if (dropped_lock) | |
1309 | goto again; | |
1310 | } | |
1311 | wake_up(&c->free_buffer_wait); | |
1312 | dm_bufio_unlock(c); | |
1313 | ||
1314 | a = xchg(&c->async_write_error, 0); | |
1315 | f = dm_bufio_issue_flush(c); | |
1316 | if (a) | |
1317 | return a; | |
1318 | ||
1319 | return f; | |
1320 | } | |
1321 | EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers); | |
1322 | ||
1323 | /* | |
1324 | * Use dm-io to send and empty barrier flush the device. | |
1325 | */ | |
1326 | int dm_bufio_issue_flush(struct dm_bufio_client *c) | |
1327 | { | |
1328 | struct dm_io_request io_req = { | |
3daec3b4 | 1329 | .bi_rw = WRITE_FLUSH, |
95d402f0 MP |
1330 | .mem.type = DM_IO_KMEM, |
1331 | .mem.ptr.addr = NULL, | |
1332 | .client = c->dm_io, | |
1333 | }; | |
1334 | struct dm_io_region io_reg = { | |
1335 | .bdev = c->bdev, | |
1336 | .sector = 0, | |
1337 | .count = 0, | |
1338 | }; | |
1339 | ||
1340 | BUG_ON(dm_bufio_in_request()); | |
1341 | ||
1342 | return dm_io(&io_req, 1, &io_reg, NULL); | |
1343 | } | |
1344 | EXPORT_SYMBOL_GPL(dm_bufio_issue_flush); | |
1345 | ||
1346 | /* | |
1347 | * We first delete any other buffer that may be at that new location. | |
1348 | * | |
1349 | * Then, we write the buffer to the original location if it was dirty. | |
1350 | * | |
1351 | * Then, if we are the only one who is holding the buffer, relink the buffer | |
1352 | * in the hash queue for the new location. | |
1353 | * | |
1354 | * If there was someone else holding the buffer, we write it to the new | |
1355 | * location but not relink it, because that other user needs to have the buffer | |
1356 | * at the same place. | |
1357 | */ | |
1358 | void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block) | |
1359 | { | |
1360 | struct dm_bufio_client *c = b->c; | |
1361 | struct dm_buffer *new; | |
1362 | ||
1363 | BUG_ON(dm_bufio_in_request()); | |
1364 | ||
1365 | dm_bufio_lock(c); | |
1366 | ||
1367 | retry: | |
1368 | new = __find(c, new_block); | |
1369 | if (new) { | |
1370 | if (new->hold_count) { | |
1371 | __wait_for_free_buffer(c); | |
1372 | goto retry; | |
1373 | } | |
1374 | ||
1375 | /* | |
1376 | * FIXME: Is there any point waiting for a write that's going | |
1377 | * to be overwritten in a bit? | |
1378 | */ | |
1379 | __make_buffer_clean(new); | |
1380 | __unlink_buffer(new); | |
1381 | __free_buffer_wake(new); | |
1382 | } | |
1383 | ||
1384 | BUG_ON(!b->hold_count); | |
1385 | BUG_ON(test_bit(B_READING, &b->state)); | |
1386 | ||
2480945c | 1387 | __write_dirty_buffer(b, NULL); |
95d402f0 | 1388 | if (b->hold_count == 1) { |
74316201 N |
1389 | wait_on_bit_io(&b->state, B_WRITING, |
1390 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1391 | set_bit(B_DIRTY, &b->state); |
1392 | __unlink_buffer(b); | |
1393 | __link_buffer(b, new_block, LIST_DIRTY); | |
1394 | } else { | |
1395 | sector_t old_block; | |
74316201 N |
1396 | wait_on_bit_lock_io(&b->state, B_WRITING, |
1397 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1398 | /* |
1399 | * Relink buffer to "new_block" so that write_callback | |
1400 | * sees "new_block" as a block number. | |
1401 | * After the write, link the buffer back to old_block. | |
1402 | * All this must be done in bufio lock, so that block number | |
1403 | * change isn't visible to other threads. | |
1404 | */ | |
1405 | old_block = b->block; | |
1406 | __unlink_buffer(b); | |
1407 | __link_buffer(b, new_block, b->list_mode); | |
1408 | submit_io(b, WRITE, new_block, write_endio); | |
74316201 N |
1409 | wait_on_bit_io(&b->state, B_WRITING, |
1410 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1411 | __unlink_buffer(b); |
1412 | __link_buffer(b, old_block, b->list_mode); | |
1413 | } | |
1414 | ||
1415 | dm_bufio_unlock(c); | |
1416 | dm_bufio_release(b); | |
1417 | } | |
1418 | EXPORT_SYMBOL_GPL(dm_bufio_release_move); | |
1419 | ||
55494bf2 MP |
1420 | /* |
1421 | * Free the given buffer. | |
1422 | * | |
1423 | * This is just a hint, if the buffer is in use or dirty, this function | |
1424 | * does nothing. | |
1425 | */ | |
1426 | void dm_bufio_forget(struct dm_bufio_client *c, sector_t block) | |
1427 | { | |
1428 | struct dm_buffer *b; | |
1429 | ||
1430 | dm_bufio_lock(c); | |
1431 | ||
1432 | b = __find(c, block); | |
1433 | if (b && likely(!b->hold_count) && likely(!b->state)) { | |
1434 | __unlink_buffer(b); | |
1435 | __free_buffer_wake(b); | |
1436 | } | |
1437 | ||
1438 | dm_bufio_unlock(c); | |
1439 | } | |
1440 | EXPORT_SYMBOL(dm_bufio_forget); | |
1441 | ||
55b082e6 MP |
1442 | void dm_bufio_set_minimum_buffers(struct dm_bufio_client *c, unsigned n) |
1443 | { | |
1444 | c->minimum_buffers = n; | |
1445 | } | |
1446 | EXPORT_SYMBOL(dm_bufio_set_minimum_buffers); | |
1447 | ||
95d402f0 MP |
1448 | unsigned dm_bufio_get_block_size(struct dm_bufio_client *c) |
1449 | { | |
1450 | return c->block_size; | |
1451 | } | |
1452 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_size); | |
1453 | ||
1454 | sector_t dm_bufio_get_device_size(struct dm_bufio_client *c) | |
1455 | { | |
1456 | return i_size_read(c->bdev->bd_inode) >> | |
1457 | (SECTOR_SHIFT + c->sectors_per_block_bits); | |
1458 | } | |
1459 | EXPORT_SYMBOL_GPL(dm_bufio_get_device_size); | |
1460 | ||
1461 | sector_t dm_bufio_get_block_number(struct dm_buffer *b) | |
1462 | { | |
1463 | return b->block; | |
1464 | } | |
1465 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_number); | |
1466 | ||
1467 | void *dm_bufio_get_block_data(struct dm_buffer *b) | |
1468 | { | |
1469 | return b->data; | |
1470 | } | |
1471 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_data); | |
1472 | ||
1473 | void *dm_bufio_get_aux_data(struct dm_buffer *b) | |
1474 | { | |
1475 | return b + 1; | |
1476 | } | |
1477 | EXPORT_SYMBOL_GPL(dm_bufio_get_aux_data); | |
1478 | ||
1479 | struct dm_bufio_client *dm_bufio_get_client(struct dm_buffer *b) | |
1480 | { | |
1481 | return b->c; | |
1482 | } | |
1483 | EXPORT_SYMBOL_GPL(dm_bufio_get_client); | |
1484 | ||
1485 | static void drop_buffers(struct dm_bufio_client *c) | |
1486 | { | |
1487 | struct dm_buffer *b; | |
1488 | int i; | |
86bad0c7 | 1489 | bool warned = false; |
95d402f0 MP |
1490 | |
1491 | BUG_ON(dm_bufio_in_request()); | |
1492 | ||
1493 | /* | |
1494 | * An optimization so that the buffers are not written one-by-one. | |
1495 | */ | |
1496 | dm_bufio_write_dirty_buffers_async(c); | |
1497 | ||
1498 | dm_bufio_lock(c); | |
1499 | ||
1500 | while ((b = __get_unclaimed_buffer(c))) | |
1501 | __free_buffer_wake(b); | |
1502 | ||
1503 | for (i = 0; i < LIST_SIZE; i++) | |
86bad0c7 MP |
1504 | list_for_each_entry(b, &c->lru[i], lru_list) { |
1505 | WARN_ON(!warned); | |
1506 | warned = true; | |
95d402f0 MP |
1507 | DMERR("leaked buffer %llx, hold count %u, list %d", |
1508 | (unsigned long long)b->block, b->hold_count, i); | |
86bad0c7 MP |
1509 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
1510 | print_stack_trace(&b->stack_trace, 1); | |
1511 | b->hold_count = 0; /* mark unclaimed to avoid BUG_ON below */ | |
1512 | #endif | |
1513 | } | |
1514 | ||
1515 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING | |
1516 | while ((b = __get_unclaimed_buffer(c))) | |
1517 | __free_buffer_wake(b); | |
1518 | #endif | |
95d402f0 MP |
1519 | |
1520 | for (i = 0; i < LIST_SIZE; i++) | |
1521 | BUG_ON(!list_empty(&c->lru[i])); | |
1522 | ||
1523 | dm_bufio_unlock(c); | |
1524 | } | |
1525 | ||
1526 | /* | |
33096a78 JT |
1527 | * We may not be able to evict this buffer if IO pending or the client |
1528 | * is still using it. Caller is expected to know buffer is too old. | |
1529 | * | |
9d28eb12 MP |
1530 | * And if GFP_NOFS is used, we must not do any I/O because we hold |
1531 | * dm_bufio_clients_lock and we would risk deadlock if the I/O gets | |
1532 | * rerouted to different bufio client. | |
95d402f0 | 1533 | */ |
33096a78 | 1534 | static bool __try_evict_buffer(struct dm_buffer *b, gfp_t gfp) |
95d402f0 | 1535 | { |
9d28eb12 | 1536 | if (!(gfp & __GFP_FS)) { |
95d402f0 MP |
1537 | if (test_bit(B_READING, &b->state) || |
1538 | test_bit(B_WRITING, &b->state) || | |
1539 | test_bit(B_DIRTY, &b->state)) | |
33096a78 | 1540 | return false; |
95d402f0 MP |
1541 | } |
1542 | ||
1543 | if (b->hold_count) | |
33096a78 | 1544 | return false; |
95d402f0 MP |
1545 | |
1546 | __make_buffer_clean(b); | |
1547 | __unlink_buffer(b); | |
1548 | __free_buffer_wake(b); | |
1549 | ||
33096a78 | 1550 | return true; |
95d402f0 MP |
1551 | } |
1552 | ||
33096a78 JT |
1553 | static unsigned get_retain_buffers(struct dm_bufio_client *c) |
1554 | { | |
1555 | unsigned retain_bytes = ACCESS_ONCE(dm_bufio_retain_bytes); | |
1556 | return retain_bytes / c->block_size; | |
1557 | } | |
1558 | ||
1559 | static unsigned long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan, | |
1560 | gfp_t gfp_mask) | |
95d402f0 MP |
1561 | { |
1562 | int l; | |
1563 | struct dm_buffer *b, *tmp; | |
33096a78 JT |
1564 | unsigned long freed = 0; |
1565 | unsigned long count = nr_to_scan; | |
1566 | unsigned retain_target = get_retain_buffers(c); | |
95d402f0 MP |
1567 | |
1568 | for (l = 0; l < LIST_SIZE; l++) { | |
7dc19d5a | 1569 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list) { |
33096a78 JT |
1570 | if (__try_evict_buffer(b, gfp_mask)) |
1571 | freed++; | |
1572 | if (!--nr_to_scan || ((count - freed) <= retain_target)) | |
0e825862 MP |
1573 | return freed; |
1574 | dm_bufio_cond_resched(); | |
7dc19d5a | 1575 | } |
95d402f0 | 1576 | } |
7dc19d5a | 1577 | return freed; |
95d402f0 MP |
1578 | } |
1579 | ||
7dc19d5a DC |
1580 | static unsigned long |
1581 | dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) | |
95d402f0 | 1582 | { |
7dc19d5a DC |
1583 | struct dm_bufio_client *c; |
1584 | unsigned long freed; | |
95d402f0 | 1585 | |
7dc19d5a | 1586 | c = container_of(shrink, struct dm_bufio_client, shrinker); |
9d28eb12 | 1587 | if (sc->gfp_mask & __GFP_FS) |
95d402f0 MP |
1588 | dm_bufio_lock(c); |
1589 | else if (!dm_bufio_trylock(c)) | |
7dc19d5a | 1590 | return SHRINK_STOP; |
95d402f0 | 1591 | |
7dc19d5a DC |
1592 | freed = __scan(c, sc->nr_to_scan, sc->gfp_mask); |
1593 | dm_bufio_unlock(c); | |
1594 | return freed; | |
1595 | } | |
95d402f0 | 1596 | |
7dc19d5a DC |
1597 | static unsigned long |
1598 | dm_bufio_shrink_count(struct shrinker *shrink, struct shrink_control *sc) | |
1599 | { | |
1600 | struct dm_bufio_client *c; | |
1601 | unsigned long count; | |
95d402f0 | 1602 | |
7dc19d5a | 1603 | c = container_of(shrink, struct dm_bufio_client, shrinker); |
9d28eb12 | 1604 | if (sc->gfp_mask & __GFP_FS) |
7dc19d5a DC |
1605 | dm_bufio_lock(c); |
1606 | else if (!dm_bufio_trylock(c)) | |
1607 | return 0; | |
95d402f0 | 1608 | |
7dc19d5a DC |
1609 | count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY]; |
1610 | dm_bufio_unlock(c); | |
1611 | return count; | |
95d402f0 MP |
1612 | } |
1613 | ||
1614 | /* | |
1615 | * Create the buffering interface | |
1616 | */ | |
1617 | struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsigned block_size, | |
1618 | unsigned reserved_buffers, unsigned aux_size, | |
1619 | void (*alloc_callback)(struct dm_buffer *), | |
1620 | void (*write_callback)(struct dm_buffer *)) | |
1621 | { | |
1622 | int r; | |
1623 | struct dm_bufio_client *c; | |
1624 | unsigned i; | |
1625 | ||
1626 | BUG_ON(block_size < 1 << SECTOR_SHIFT || | |
1627 | (block_size & (block_size - 1))); | |
1628 | ||
d8c712ea | 1629 | c = kzalloc(sizeof(*c), GFP_KERNEL); |
95d402f0 MP |
1630 | if (!c) { |
1631 | r = -ENOMEM; | |
1632 | goto bad_client; | |
1633 | } | |
4e420c45 | 1634 | c->buffer_tree = RB_ROOT; |
95d402f0 MP |
1635 | |
1636 | c->bdev = bdev; | |
1637 | c->block_size = block_size; | |
a3d939ae MP |
1638 | c->sectors_per_block_bits = __ffs(block_size) - SECTOR_SHIFT; |
1639 | c->pages_per_block_bits = (__ffs(block_size) >= PAGE_SHIFT) ? | |
1640 | __ffs(block_size) - PAGE_SHIFT : 0; | |
1641 | c->blocks_per_page_bits = (__ffs(block_size) < PAGE_SHIFT ? | |
1642 | PAGE_SHIFT - __ffs(block_size) : 0); | |
95d402f0 MP |
1643 | |
1644 | c->aux_size = aux_size; | |
1645 | c->alloc_callback = alloc_callback; | |
1646 | c->write_callback = write_callback; | |
1647 | ||
1648 | for (i = 0; i < LIST_SIZE; i++) { | |
1649 | INIT_LIST_HEAD(&c->lru[i]); | |
1650 | c->n_buffers[i] = 0; | |
1651 | } | |
1652 | ||
95d402f0 MP |
1653 | mutex_init(&c->lock); |
1654 | INIT_LIST_HEAD(&c->reserved_buffers); | |
1655 | c->need_reserved_buffers = reserved_buffers; | |
1656 | ||
55b082e6 MP |
1657 | c->minimum_buffers = DM_BUFIO_MIN_BUFFERS; |
1658 | ||
95d402f0 MP |
1659 | init_waitqueue_head(&c->free_buffer_wait); |
1660 | c->async_write_error = 0; | |
1661 | ||
1662 | c->dm_io = dm_io_client_create(); | |
1663 | if (IS_ERR(c->dm_io)) { | |
1664 | r = PTR_ERR(c->dm_io); | |
1665 | goto bad_dm_io; | |
1666 | } | |
1667 | ||
1668 | mutex_lock(&dm_bufio_clients_lock); | |
1669 | if (c->blocks_per_page_bits) { | |
1670 | if (!DM_BUFIO_CACHE_NAME(c)) { | |
1671 | DM_BUFIO_CACHE_NAME(c) = kasprintf(GFP_KERNEL, "dm_bufio_cache-%u", c->block_size); | |
1672 | if (!DM_BUFIO_CACHE_NAME(c)) { | |
1673 | r = -ENOMEM; | |
1674 | mutex_unlock(&dm_bufio_clients_lock); | |
1675 | goto bad_cache; | |
1676 | } | |
1677 | } | |
1678 | ||
1679 | if (!DM_BUFIO_CACHE(c)) { | |
1680 | DM_BUFIO_CACHE(c) = kmem_cache_create(DM_BUFIO_CACHE_NAME(c), | |
1681 | c->block_size, | |
1682 | c->block_size, 0, NULL); | |
1683 | if (!DM_BUFIO_CACHE(c)) { | |
1684 | r = -ENOMEM; | |
1685 | mutex_unlock(&dm_bufio_clients_lock); | |
1686 | goto bad_cache; | |
1687 | } | |
1688 | } | |
1689 | } | |
1690 | mutex_unlock(&dm_bufio_clients_lock); | |
1691 | ||
1692 | while (c->need_reserved_buffers) { | |
1693 | struct dm_buffer *b = alloc_buffer(c, GFP_KERNEL); | |
1694 | ||
1695 | if (!b) { | |
1696 | r = -ENOMEM; | |
1697 | goto bad_buffer; | |
1698 | } | |
1699 | __free_buffer_wake(b); | |
1700 | } | |
1701 | ||
1702 | mutex_lock(&dm_bufio_clients_lock); | |
1703 | dm_bufio_client_count++; | |
1704 | list_add(&c->client_list, &dm_bufio_all_clients); | |
1705 | __cache_size_refresh(); | |
1706 | mutex_unlock(&dm_bufio_clients_lock); | |
1707 | ||
7dc19d5a DC |
1708 | c->shrinker.count_objects = dm_bufio_shrink_count; |
1709 | c->shrinker.scan_objects = dm_bufio_shrink_scan; | |
95d402f0 MP |
1710 | c->shrinker.seeks = 1; |
1711 | c->shrinker.batch = 0; | |
1712 | register_shrinker(&c->shrinker); | |
1713 | ||
1714 | return c; | |
1715 | ||
1716 | bad_buffer: | |
1717 | bad_cache: | |
1718 | while (!list_empty(&c->reserved_buffers)) { | |
1719 | struct dm_buffer *b = list_entry(c->reserved_buffers.next, | |
1720 | struct dm_buffer, lru_list); | |
1721 | list_del(&b->lru_list); | |
1722 | free_buffer(b); | |
1723 | } | |
1724 | dm_io_client_destroy(c->dm_io); | |
1725 | bad_dm_io: | |
95d402f0 MP |
1726 | kfree(c); |
1727 | bad_client: | |
1728 | return ERR_PTR(r); | |
1729 | } | |
1730 | EXPORT_SYMBOL_GPL(dm_bufio_client_create); | |
1731 | ||
1732 | /* | |
1733 | * Free the buffering interface. | |
1734 | * It is required that there are no references on any buffers. | |
1735 | */ | |
1736 | void dm_bufio_client_destroy(struct dm_bufio_client *c) | |
1737 | { | |
1738 | unsigned i; | |
1739 | ||
1740 | drop_buffers(c); | |
1741 | ||
1742 | unregister_shrinker(&c->shrinker); | |
1743 | ||
1744 | mutex_lock(&dm_bufio_clients_lock); | |
1745 | ||
1746 | list_del(&c->client_list); | |
1747 | dm_bufio_client_count--; | |
1748 | __cache_size_refresh(); | |
1749 | ||
1750 | mutex_unlock(&dm_bufio_clients_lock); | |
1751 | ||
4e420c45 | 1752 | BUG_ON(!RB_EMPTY_ROOT(&c->buffer_tree)); |
95d402f0 MP |
1753 | BUG_ON(c->need_reserved_buffers); |
1754 | ||
1755 | while (!list_empty(&c->reserved_buffers)) { | |
1756 | struct dm_buffer *b = list_entry(c->reserved_buffers.next, | |
1757 | struct dm_buffer, lru_list); | |
1758 | list_del(&b->lru_list); | |
1759 | free_buffer(b); | |
1760 | } | |
1761 | ||
1762 | for (i = 0; i < LIST_SIZE; i++) | |
1763 | if (c->n_buffers[i]) | |
1764 | DMERR("leaked buffer count %d: %ld", i, c->n_buffers[i]); | |
1765 | ||
1766 | for (i = 0; i < LIST_SIZE; i++) | |
1767 | BUG_ON(c->n_buffers[i]); | |
1768 | ||
1769 | dm_io_client_destroy(c->dm_io); | |
95d402f0 MP |
1770 | kfree(c); |
1771 | } | |
1772 | EXPORT_SYMBOL_GPL(dm_bufio_client_destroy); | |
1773 | ||
33096a78 | 1774 | static unsigned get_max_age_hz(void) |
95d402f0 | 1775 | { |
33096a78 | 1776 | unsigned max_age = ACCESS_ONCE(dm_bufio_max_age); |
95d402f0 | 1777 | |
33096a78 JT |
1778 | if (max_age > UINT_MAX / HZ) |
1779 | max_age = UINT_MAX / HZ; | |
95d402f0 | 1780 | |
33096a78 JT |
1781 | return max_age * HZ; |
1782 | } | |
95d402f0 | 1783 | |
33096a78 JT |
1784 | static bool older_than(struct dm_buffer *b, unsigned long age_hz) |
1785 | { | |
f495339c | 1786 | return time_after_eq(jiffies, b->last_accessed + age_hz); |
33096a78 JT |
1787 | } |
1788 | ||
1789 | static void __evict_old_buffers(struct dm_bufio_client *c, unsigned long age_hz) | |
1790 | { | |
1791 | struct dm_buffer *b, *tmp; | |
1792 | unsigned retain_target = get_retain_buffers(c); | |
1793 | unsigned count; | |
1794 | ||
1795 | dm_bufio_lock(c); | |
1796 | ||
1797 | count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY]; | |
1798 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_CLEAN], lru_list) { | |
1799 | if (count <= retain_target) | |
1800 | break; | |
1801 | ||
1802 | if (!older_than(b, age_hz)) | |
1803 | break; | |
1804 | ||
1805 | if (__try_evict_buffer(b, 0)) | |
1806 | count--; | |
95d402f0 | 1807 | |
95d402f0 MP |
1808 | dm_bufio_cond_resched(); |
1809 | } | |
33096a78 JT |
1810 | |
1811 | dm_bufio_unlock(c); | |
1812 | } | |
1813 | ||
1814 | static void cleanup_old_buffers(void) | |
1815 | { | |
1816 | unsigned long max_age_hz = get_max_age_hz(); | |
1817 | struct dm_bufio_client *c; | |
1818 | ||
1819 | mutex_lock(&dm_bufio_clients_lock); | |
1820 | ||
1821 | list_for_each_entry(c, &dm_bufio_all_clients, client_list) | |
1822 | __evict_old_buffers(c, max_age_hz); | |
1823 | ||
95d402f0 MP |
1824 | mutex_unlock(&dm_bufio_clients_lock); |
1825 | } | |
1826 | ||
1827 | static struct workqueue_struct *dm_bufio_wq; | |
1828 | static struct delayed_work dm_bufio_work; | |
1829 | ||
1830 | static void work_fn(struct work_struct *w) | |
1831 | { | |
1832 | cleanup_old_buffers(); | |
1833 | ||
1834 | queue_delayed_work(dm_bufio_wq, &dm_bufio_work, | |
1835 | DM_BUFIO_WORK_TIMER_SECS * HZ); | |
1836 | } | |
1837 | ||
1838 | /*---------------------------------------------------------------- | |
1839 | * Module setup | |
1840 | *--------------------------------------------------------------*/ | |
1841 | ||
1842 | /* | |
1843 | * This is called only once for the whole dm_bufio module. | |
1844 | * It initializes memory limit. | |
1845 | */ | |
1846 | static int __init dm_bufio_init(void) | |
1847 | { | |
1848 | __u64 mem; | |
1849 | ||
4cb57ab4 MP |
1850 | dm_bufio_allocated_kmem_cache = 0; |
1851 | dm_bufio_allocated_get_free_pages = 0; | |
1852 | dm_bufio_allocated_vmalloc = 0; | |
1853 | dm_bufio_current_allocated = 0; | |
1854 | ||
95d402f0 MP |
1855 | memset(&dm_bufio_caches, 0, sizeof dm_bufio_caches); |
1856 | memset(&dm_bufio_cache_names, 0, sizeof dm_bufio_cache_names); | |
1857 | ||
1858 | mem = (__u64)((totalram_pages - totalhigh_pages) * | |
1859 | DM_BUFIO_MEMORY_PERCENT / 100) << PAGE_SHIFT; | |
1860 | ||
1861 | if (mem > ULONG_MAX) | |
1862 | mem = ULONG_MAX; | |
1863 | ||
1864 | #ifdef CONFIG_MMU | |
1865 | /* | |
1866 | * Get the size of vmalloc space the same way as VMALLOC_TOTAL | |
1867 | * in fs/proc/internal.h | |
1868 | */ | |
1869 | if (mem > (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100) | |
1870 | mem = (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100; | |
1871 | #endif | |
1872 | ||
1873 | dm_bufio_default_cache_size = mem; | |
1874 | ||
1875 | mutex_lock(&dm_bufio_clients_lock); | |
1876 | __cache_size_refresh(); | |
1877 | mutex_unlock(&dm_bufio_clients_lock); | |
1878 | ||
1879 | dm_bufio_wq = create_singlethread_workqueue("dm_bufio_cache"); | |
1880 | if (!dm_bufio_wq) | |
1881 | return -ENOMEM; | |
1882 | ||
1883 | INIT_DELAYED_WORK(&dm_bufio_work, work_fn); | |
1884 | queue_delayed_work(dm_bufio_wq, &dm_bufio_work, | |
1885 | DM_BUFIO_WORK_TIMER_SECS * HZ); | |
1886 | ||
1887 | return 0; | |
1888 | } | |
1889 | ||
1890 | /* | |
1891 | * This is called once when unloading the dm_bufio module. | |
1892 | */ | |
1893 | static void __exit dm_bufio_exit(void) | |
1894 | { | |
1895 | int bug = 0; | |
1896 | int i; | |
1897 | ||
1898 | cancel_delayed_work_sync(&dm_bufio_work); | |
1899 | destroy_workqueue(dm_bufio_wq); | |
1900 | ||
6f65985e JL |
1901 | for (i = 0; i < ARRAY_SIZE(dm_bufio_caches); i++) |
1902 | kmem_cache_destroy(dm_bufio_caches[i]); | |
95d402f0 MP |
1903 | |
1904 | for (i = 0; i < ARRAY_SIZE(dm_bufio_cache_names); i++) | |
1905 | kfree(dm_bufio_cache_names[i]); | |
1906 | ||
1907 | if (dm_bufio_client_count) { | |
1908 | DMCRIT("%s: dm_bufio_client_count leaked: %d", | |
1909 | __func__, dm_bufio_client_count); | |
1910 | bug = 1; | |
1911 | } | |
1912 | ||
1913 | if (dm_bufio_current_allocated) { | |
1914 | DMCRIT("%s: dm_bufio_current_allocated leaked: %lu", | |
1915 | __func__, dm_bufio_current_allocated); | |
1916 | bug = 1; | |
1917 | } | |
1918 | ||
1919 | if (dm_bufio_allocated_get_free_pages) { | |
1920 | DMCRIT("%s: dm_bufio_allocated_get_free_pages leaked: %lu", | |
1921 | __func__, dm_bufio_allocated_get_free_pages); | |
1922 | bug = 1; | |
1923 | } | |
1924 | ||
1925 | if (dm_bufio_allocated_vmalloc) { | |
1926 | DMCRIT("%s: dm_bufio_vmalloc leaked: %lu", | |
1927 | __func__, dm_bufio_allocated_vmalloc); | |
1928 | bug = 1; | |
1929 | } | |
1930 | ||
86a49e2d | 1931 | BUG_ON(bug); |
95d402f0 MP |
1932 | } |
1933 | ||
1934 | module_init(dm_bufio_init) | |
1935 | module_exit(dm_bufio_exit) | |
1936 | ||
1937 | module_param_named(max_cache_size_bytes, dm_bufio_cache_size, ulong, S_IRUGO | S_IWUSR); | |
1938 | MODULE_PARM_DESC(max_cache_size_bytes, "Size of metadata cache"); | |
1939 | ||
1940 | module_param_named(max_age_seconds, dm_bufio_max_age, uint, S_IRUGO | S_IWUSR); | |
1941 | MODULE_PARM_DESC(max_age_seconds, "Max age of a buffer in seconds"); | |
33096a78 JT |
1942 | |
1943 | module_param_named(retain_bytes, dm_bufio_retain_bytes, uint, S_IRUGO | S_IWUSR); | |
1944 | MODULE_PARM_DESC(retain_bytes, "Try to keep at least this many bytes cached in memory"); | |
95d402f0 MP |
1945 | |
1946 | module_param_named(peak_allocated_bytes, dm_bufio_peak_allocated, ulong, S_IRUGO | S_IWUSR); | |
1947 | MODULE_PARM_DESC(peak_allocated_bytes, "Tracks the maximum allocated memory"); | |
1948 | ||
1949 | module_param_named(allocated_kmem_cache_bytes, dm_bufio_allocated_kmem_cache, ulong, S_IRUGO); | |
1950 | MODULE_PARM_DESC(allocated_kmem_cache_bytes, "Memory allocated with kmem_cache_alloc"); | |
1951 | ||
1952 | module_param_named(allocated_get_free_pages_bytes, dm_bufio_allocated_get_free_pages, ulong, S_IRUGO); | |
1953 | MODULE_PARM_DESC(allocated_get_free_pages_bytes, "Memory allocated with get_free_pages"); | |
1954 | ||
1955 | module_param_named(allocated_vmalloc_bytes, dm_bufio_allocated_vmalloc, ulong, S_IRUGO); | |
1956 | MODULE_PARM_DESC(allocated_vmalloc_bytes, "Memory allocated with vmalloc"); | |
1957 | ||
1958 | module_param_named(current_allocated_bytes, dm_bufio_current_allocated, ulong, S_IRUGO); | |
1959 | MODULE_PARM_DESC(current_allocated_bytes, "Memory currently used by the cache"); | |
1960 | ||
1961 | MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>"); | |
1962 | MODULE_DESCRIPTION(DM_NAME " buffered I/O library"); | |
1963 | MODULE_LICENSE("GPL"); |