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3bd94003 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
95d402f0 MP |
2 | /* |
3 | * Copyright (C) 2009-2011 Red Hat, Inc. | |
4 | * | |
5 | * Author: Mikulas Patocka <mpatocka@redhat.com> | |
6 | * | |
7 | * This file is released under the GPL. | |
8 | */ | |
9 | ||
afa53df8 | 10 | #include <linux/dm-bufio.h> |
95d402f0 MP |
11 | |
12 | #include <linux/device-mapper.h> | |
13 | #include <linux/dm-io.h> | |
14 | #include <linux/slab.h> | |
5b3cc15a | 15 | #include <linux/sched/mm.h> |
f495339c | 16 | #include <linux/jiffies.h> |
95d402f0 | 17 | #include <linux/vmalloc.h> |
95d402f0 | 18 | #include <linux/shrinker.h> |
6f66263f | 19 | #include <linux/module.h> |
4e420c45 | 20 | #include <linux/rbtree.h> |
86bad0c7 | 21 | #include <linux/stacktrace.h> |
3c1c875d | 22 | #include <linux/jump_label.h> |
95d402f0 MP |
23 | |
24 | #define DM_MSG_PREFIX "bufio" | |
25 | ||
26 | /* | |
27 | * Memory management policy: | |
28 | * Limit the number of buffers to DM_BUFIO_MEMORY_PERCENT of main memory | |
29 | * or DM_BUFIO_VMALLOC_PERCENT of vmalloc memory (whichever is lower). | |
30 | * Always allocate at least DM_BUFIO_MIN_BUFFERS buffers. | |
31 | * Start background writeback when there are DM_BUFIO_WRITEBACK_PERCENT | |
32 | * dirty buffers. | |
33 | */ | |
34 | #define DM_BUFIO_MIN_BUFFERS 8 | |
35 | ||
36 | #define DM_BUFIO_MEMORY_PERCENT 2 | |
37 | #define DM_BUFIO_VMALLOC_PERCENT 25 | |
b132ff33 | 38 | #define DM_BUFIO_WRITEBACK_RATIO 3 |
6e913b28 | 39 | #define DM_BUFIO_LOW_WATERMARK_RATIO 16 |
95d402f0 MP |
40 | |
41 | /* | |
42 | * Check buffer ages in this interval (seconds) | |
43 | */ | |
33096a78 | 44 | #define DM_BUFIO_WORK_TIMER_SECS 30 |
95d402f0 MP |
45 | |
46 | /* | |
47 | * Free buffers when they are older than this (seconds) | |
48 | */ | |
33096a78 | 49 | #define DM_BUFIO_DEFAULT_AGE_SECS 300 |
95d402f0 MP |
50 | |
51 | /* | |
33096a78 | 52 | * The nr of bytes of cached data to keep around. |
95d402f0 | 53 | */ |
33096a78 | 54 | #define DM_BUFIO_DEFAULT_RETAIN_BYTES (256 * 1024) |
95d402f0 | 55 | |
1e3b21c6 MP |
56 | /* |
57 | * Align buffer writes to this boundary. | |
58 | * Tests show that SSDs have the highest IOPS when using 4k writes. | |
59 | */ | |
60 | #define DM_BUFIO_WRITE_ALIGN 4096 | |
61 | ||
95d402f0 MP |
62 | /* |
63 | * dm_buffer->list_mode | |
64 | */ | |
65 | #define LIST_CLEAN 0 | |
66 | #define LIST_DIRTY 1 | |
67 | #define LIST_SIZE 2 | |
68 | ||
69 | /* | |
70 | * Linking of buffers: | |
ef992373 | 71 | * All buffers are linked to buffer_tree with their node field. |
95d402f0 MP |
72 | * |
73 | * Clean buffers that are not being written (B_WRITING not set) | |
74 | * are linked to lru[LIST_CLEAN] with their lru_list field. | |
75 | * | |
76 | * Dirty and clean buffers that are being written are linked to | |
77 | * lru[LIST_DIRTY] with their lru_list field. When the write | |
78 | * finishes, the buffer cannot be relinked immediately (because we | |
79 | * are in an interrupt context and relinking requires process | |
80 | * context), so some clean-not-writing buffers can be held on | |
81 | * dirty_lru too. They are later added to lru in the process | |
82 | * context. | |
83 | */ | |
84 | struct dm_bufio_client { | |
85 | struct mutex lock; | |
b32d4582 | 86 | spinlock_t spinlock; |
b33b6fdc | 87 | bool no_sleep; |
95d402f0 MP |
88 | |
89 | struct list_head lru[LIST_SIZE]; | |
90 | unsigned long n_buffers[LIST_SIZE]; | |
91 | ||
92 | struct block_device *bdev; | |
86a3238c | 93 | unsigned int block_size; |
f51f2e0a | 94 | s8 sectors_per_block_bits; |
02f10ba1 HM |
95 | void (*alloc_callback)(struct dm_buffer *buf); |
96 | void (*write_callback)(struct dm_buffer *buf); | |
359dbf19 | 97 | struct kmem_cache *slab_buffer; |
21bb1327 | 98 | struct kmem_cache *slab_cache; |
95d402f0 MP |
99 | struct dm_io_client *dm_io; |
100 | ||
101 | struct list_head reserved_buffers; | |
86a3238c | 102 | unsigned int need_reserved_buffers; |
95d402f0 | 103 | |
86a3238c | 104 | unsigned int minimum_buffers; |
55b082e6 | 105 | |
4e420c45 | 106 | struct rb_root buffer_tree; |
95d402f0 MP |
107 | wait_queue_head_t free_buffer_wait; |
108 | ||
400a0bef MP |
109 | sector_t start; |
110 | ||
95d402f0 MP |
111 | int async_write_error; |
112 | ||
113 | struct list_head client_list; | |
70704c33 | 114 | |
95d402f0 | 115 | struct shrinker shrinker; |
70704c33 MP |
116 | struct work_struct shrink_work; |
117 | atomic_long_t need_shrink; | |
95d402f0 MP |
118 | }; |
119 | ||
120 | /* | |
121 | * Buffer state bits. | |
122 | */ | |
123 | #define B_READING 0 | |
124 | #define B_WRITING 1 | |
125 | #define B_DIRTY 2 | |
126 | ||
127 | /* | |
128 | * Describes how the block was allocated: | |
129 | * kmem_cache_alloc(), __get_free_pages() or vmalloc(). | |
130 | * See the comment at alloc_buffer_data. | |
131 | */ | |
132 | enum data_mode { | |
133 | DATA_MODE_SLAB = 0, | |
134 | DATA_MODE_GET_FREE_PAGES = 1, | |
135 | DATA_MODE_VMALLOC = 2, | |
136 | DATA_MODE_LIMIT = 3 | |
137 | }; | |
138 | ||
139 | struct dm_buffer { | |
4e420c45 | 140 | struct rb_node node; |
95d402f0 | 141 | struct list_head lru_list; |
af53badc | 142 | struct list_head global_list; |
95d402f0 MP |
143 | sector_t block; |
144 | void *data; | |
03b02939 | 145 | unsigned char data_mode; /* DATA_MODE_* */ |
95d402f0 | 146 | unsigned char list_mode; /* LIST_* */ |
4e4cbee9 CH |
147 | blk_status_t read_error; |
148 | blk_status_t write_error; | |
86a3238c HM |
149 | unsigned int accessed; |
150 | unsigned int hold_count; | |
95d402f0 MP |
151 | unsigned long state; |
152 | unsigned long last_accessed; | |
86a3238c HM |
153 | unsigned int dirty_start; |
154 | unsigned int dirty_end; | |
155 | unsigned int write_start; | |
156 | unsigned int write_end; | |
95d402f0 | 157 | struct dm_bufio_client *c; |
2480945c | 158 | struct list_head write_list; |
02f10ba1 | 159 | void (*end_io)(struct dm_buffer *buf, blk_status_t stat); |
86bad0c7 MP |
160 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
161 | #define MAX_STACK 10 | |
741b58f3 | 162 | unsigned int stack_len; |
86bad0c7 MP |
163 | unsigned long stack_entries[MAX_STACK]; |
164 | #endif | |
95d402f0 MP |
165 | }; |
166 | ||
3c1c875d MS |
167 | static DEFINE_STATIC_KEY_FALSE(no_sleep_enabled); |
168 | ||
95d402f0 MP |
169 | /*----------------------------------------------------------------*/ |
170 | ||
95d402f0 MP |
171 | #define dm_bufio_in_request() (!!current->bio_list) |
172 | ||
173 | static void dm_bufio_lock(struct dm_bufio_client *c) | |
174 | { | |
3c1c875d | 175 | if (static_branch_unlikely(&no_sleep_enabled) && c->no_sleep) |
b33b6fdc | 176 | spin_lock_bh(&c->spinlock); |
b32d4582 NH |
177 | else |
178 | mutex_lock_nested(&c->lock, dm_bufio_in_request()); | |
95d402f0 MP |
179 | } |
180 | ||
181 | static int dm_bufio_trylock(struct dm_bufio_client *c) | |
182 | { | |
3c1c875d | 183 | if (static_branch_unlikely(&no_sleep_enabled) && c->no_sleep) |
b33b6fdc | 184 | return spin_trylock_bh(&c->spinlock); |
b32d4582 NH |
185 | else |
186 | return mutex_trylock(&c->lock); | |
95d402f0 MP |
187 | } |
188 | ||
189 | static void dm_bufio_unlock(struct dm_bufio_client *c) | |
190 | { | |
3c1c875d | 191 | if (static_branch_unlikely(&no_sleep_enabled) && c->no_sleep) |
b33b6fdc | 192 | spin_unlock_bh(&c->spinlock); |
b32d4582 NH |
193 | else |
194 | mutex_unlock(&c->lock); | |
95d402f0 MP |
195 | } |
196 | ||
95d402f0 MP |
197 | /*----------------------------------------------------------------*/ |
198 | ||
199 | /* | |
200 | * Default cache size: available memory divided by the ratio. | |
201 | */ | |
202 | static unsigned long dm_bufio_default_cache_size; | |
203 | ||
204 | /* | |
205 | * Total cache size set by the user. | |
206 | */ | |
207 | static unsigned long dm_bufio_cache_size; | |
208 | ||
209 | /* | |
210 | * A copy of dm_bufio_cache_size because dm_bufio_cache_size can change | |
211 | * at any time. If it disagrees, the user has changed cache size. | |
212 | */ | |
213 | static unsigned long dm_bufio_cache_size_latch; | |
214 | ||
af53badc MP |
215 | static DEFINE_SPINLOCK(global_spinlock); |
216 | ||
217 | static LIST_HEAD(global_queue); | |
95d402f0 | 218 | |
2f06cd12 | 219 | static unsigned long global_num; |
6e913b28 | 220 | |
95d402f0 MP |
221 | /* |
222 | * Buffers are freed after this timeout | |
223 | */ | |
86a3238c | 224 | static unsigned int dm_bufio_max_age = DM_BUFIO_DEFAULT_AGE_SECS; |
13840d38 | 225 | static unsigned long dm_bufio_retain_bytes = DM_BUFIO_DEFAULT_RETAIN_BYTES; |
95d402f0 MP |
226 | |
227 | static unsigned long dm_bufio_peak_allocated; | |
228 | static unsigned long dm_bufio_allocated_kmem_cache; | |
229 | static unsigned long dm_bufio_allocated_get_free_pages; | |
230 | static unsigned long dm_bufio_allocated_vmalloc; | |
231 | static unsigned long dm_bufio_current_allocated; | |
232 | ||
233 | /*----------------------------------------------------------------*/ | |
234 | ||
95d402f0 MP |
235 | /* |
236 | * The current number of clients. | |
237 | */ | |
238 | static int dm_bufio_client_count; | |
239 | ||
240 | /* | |
241 | * The list of all clients. | |
242 | */ | |
243 | static LIST_HEAD(dm_bufio_all_clients); | |
244 | ||
245 | /* | |
b132ff33 | 246 | * This mutex protects dm_bufio_cache_size_latch and dm_bufio_client_count |
95d402f0 MP |
247 | */ |
248 | static DEFINE_MUTEX(dm_bufio_clients_lock); | |
249 | ||
6e913b28 MP |
250 | static struct workqueue_struct *dm_bufio_wq; |
251 | static struct delayed_work dm_bufio_cleanup_old_work; | |
252 | static struct work_struct dm_bufio_replacement_work; | |
253 | ||
254 | ||
86bad0c7 MP |
255 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
256 | static void buffer_record_stack(struct dm_buffer *b) | |
257 | { | |
741b58f3 | 258 | b->stack_len = stack_trace_save(b->stack_entries, MAX_STACK, 2); |
86bad0c7 MP |
259 | } |
260 | #endif | |
261 | ||
a4a82ce3 HM |
262 | /* |
263 | *---------------------------------------------------------------- | |
4e420c45 | 264 | * A red/black tree acts as an index for all the buffers. |
a4a82ce3 HM |
265 | *---------------------------------------------------------------- |
266 | */ | |
4e420c45 JT |
267 | static struct dm_buffer *__find(struct dm_bufio_client *c, sector_t block) |
268 | { | |
269 | struct rb_node *n = c->buffer_tree.rb_node; | |
270 | struct dm_buffer *b; | |
271 | ||
272 | while (n) { | |
273 | b = container_of(n, struct dm_buffer, node); | |
274 | ||
275 | if (b->block == block) | |
276 | return b; | |
277 | ||
88f878e5 | 278 | n = block < b->block ? n->rb_left : n->rb_right; |
4e420c45 JT |
279 | } |
280 | ||
281 | return NULL; | |
282 | } | |
283 | ||
33a18062 MP |
284 | static struct dm_buffer *__find_next(struct dm_bufio_client *c, sector_t block) |
285 | { | |
286 | struct rb_node *n = c->buffer_tree.rb_node; | |
287 | struct dm_buffer *b; | |
288 | struct dm_buffer *best = NULL; | |
289 | ||
290 | while (n) { | |
291 | b = container_of(n, struct dm_buffer, node); | |
292 | ||
293 | if (b->block == block) | |
294 | return b; | |
295 | ||
296 | if (block <= b->block) { | |
297 | n = n->rb_left; | |
298 | best = b; | |
299 | } else { | |
300 | n = n->rb_right; | |
301 | } | |
302 | } | |
303 | ||
304 | return best; | |
305 | } | |
306 | ||
4e420c45 JT |
307 | static void __insert(struct dm_bufio_client *c, struct dm_buffer *b) |
308 | { | |
309 | struct rb_node **new = &c->buffer_tree.rb_node, *parent = NULL; | |
310 | struct dm_buffer *found; | |
311 | ||
312 | while (*new) { | |
313 | found = container_of(*new, struct dm_buffer, node); | |
314 | ||
315 | if (found->block == b->block) { | |
316 | BUG_ON(found != b); | |
317 | return; | |
318 | } | |
319 | ||
320 | parent = *new; | |
88f878e5 MP |
321 | new = b->block < found->block ? |
322 | &found->node.rb_left : &found->node.rb_right; | |
4e420c45 JT |
323 | } |
324 | ||
325 | rb_link_node(&b->node, parent, new); | |
326 | rb_insert_color(&b->node, &c->buffer_tree); | |
327 | } | |
328 | ||
329 | static void __remove(struct dm_bufio_client *c, struct dm_buffer *b) | |
330 | { | |
331 | rb_erase(&b->node, &c->buffer_tree); | |
332 | } | |
333 | ||
95d402f0 MP |
334 | /*----------------------------------------------------------------*/ |
335 | ||
d0a328a3 | 336 | static void adjust_total_allocated(struct dm_buffer *b, bool unlink) |
95d402f0 | 337 | { |
d0a328a3 MP |
338 | unsigned char data_mode; |
339 | long diff; | |
340 | ||
95d402f0 MP |
341 | static unsigned long * const class_ptr[DATA_MODE_LIMIT] = { |
342 | &dm_bufio_allocated_kmem_cache, | |
343 | &dm_bufio_allocated_get_free_pages, | |
344 | &dm_bufio_allocated_vmalloc, | |
345 | }; | |
346 | ||
d0a328a3 MP |
347 | data_mode = b->data_mode; |
348 | diff = (long)b->c->block_size; | |
349 | if (unlink) | |
350 | diff = -diff; | |
351 | ||
af53badc | 352 | spin_lock(&global_spinlock); |
95d402f0 MP |
353 | |
354 | *class_ptr[data_mode] += diff; | |
355 | ||
356 | dm_bufio_current_allocated += diff; | |
357 | ||
358 | if (dm_bufio_current_allocated > dm_bufio_peak_allocated) | |
359 | dm_bufio_peak_allocated = dm_bufio_current_allocated; | |
360 | ||
6e913b28 MP |
361 | b->accessed = 1; |
362 | ||
af53badc MP |
363 | if (!unlink) { |
364 | list_add(&b->global_list, &global_queue); | |
6e913b28 MP |
365 | global_num++; |
366 | if (dm_bufio_current_allocated > dm_bufio_cache_size) | |
367 | queue_work(dm_bufio_wq, &dm_bufio_replacement_work); | |
af53badc MP |
368 | } else { |
369 | list_del(&b->global_list); | |
6e913b28 | 370 | global_num--; |
af53badc MP |
371 | } |
372 | ||
373 | spin_unlock(&global_spinlock); | |
95d402f0 MP |
374 | } |
375 | ||
376 | /* | |
377 | * Change the number of clients and recalculate per-client limit. | |
378 | */ | |
379 | static void __cache_size_refresh(void) | |
380 | { | |
381 | BUG_ON(!mutex_is_locked(&dm_bufio_clients_lock)); | |
382 | BUG_ON(dm_bufio_client_count < 0); | |
383 | ||
6aa7de05 | 384 | dm_bufio_cache_size_latch = READ_ONCE(dm_bufio_cache_size); |
95d402f0 MP |
385 | |
386 | /* | |
387 | * Use default if set to 0 and report the actual cache size used. | |
388 | */ | |
389 | if (!dm_bufio_cache_size_latch) { | |
390 | (void)cmpxchg(&dm_bufio_cache_size, 0, | |
391 | dm_bufio_default_cache_size); | |
392 | dm_bufio_cache_size_latch = dm_bufio_default_cache_size; | |
393 | } | |
95d402f0 MP |
394 | } |
395 | ||
396 | /* | |
397 | * Allocating buffer data. | |
398 | * | |
399 | * Small buffers are allocated with kmem_cache, to use space optimally. | |
400 | * | |
401 | * For large buffers, we choose between get_free_pages and vmalloc. | |
402 | * Each has advantages and disadvantages. | |
403 | * | |
404 | * __get_free_pages can randomly fail if the memory is fragmented. | |
405 | * __vmalloc won't randomly fail, but vmalloc space is limited (it may be | |
406 | * as low as 128M) so using it for caching is not appropriate. | |
407 | * | |
408 | * If the allocation may fail we use __get_free_pages. Memory fragmentation | |
409 | * won't have a fatal effect here, but it just causes flushes of some other | |
410 | * buffers and more I/O will be performed. Don't use __get_free_pages if it | |
411 | * always fails (i.e. order >= MAX_ORDER). | |
412 | * | |
413 | * If the allocation shouldn't fail we use __vmalloc. This is only for the | |
414 | * initial reserve allocation, so there's no risk of wasting all vmalloc | |
415 | * space. | |
416 | */ | |
417 | static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask, | |
03b02939 | 418 | unsigned char *data_mode) |
95d402f0 | 419 | { |
21bb1327 | 420 | if (unlikely(c->slab_cache != NULL)) { |
95d402f0 | 421 | *data_mode = DATA_MODE_SLAB; |
21bb1327 | 422 | return kmem_cache_alloc(c->slab_cache, gfp_mask); |
95d402f0 MP |
423 | } |
424 | ||
f51f2e0a | 425 | if (c->block_size <= KMALLOC_MAX_SIZE && |
95d402f0 MP |
426 | gfp_mask & __GFP_NORETRY) { |
427 | *data_mode = DATA_MODE_GET_FREE_PAGES; | |
428 | return (void *)__get_free_pages(gfp_mask, | |
f51f2e0a | 429 | c->sectors_per_block_bits - (PAGE_SHIFT - SECTOR_SHIFT)); |
95d402f0 MP |
430 | } |
431 | ||
432 | *data_mode = DATA_MODE_VMALLOC; | |
502624bd MP |
433 | |
434 | /* | |
435 | * __vmalloc allocates the data pages and auxiliary structures with | |
436 | * gfp_flags that were specified, but pagetables are always allocated | |
437 | * with GFP_KERNEL, no matter what was specified as gfp_mask. | |
438 | * | |
439 | * Consequently, we must set per-process flag PF_MEMALLOC_NOIO so that | |
440 | * all allocations done by this process (including pagetables) are done | |
441 | * as if GFP_NOIO was specified. | |
442 | */ | |
590347e4 | 443 | if (gfp_mask & __GFP_NORETRY) { |
86a3238c | 444 | unsigned int noio_flag = memalloc_noio_save(); |
88dca4ca | 445 | void *ptr = __vmalloc(c->block_size, gfp_mask); |
502624bd | 446 | |
502624bd | 447 | memalloc_noio_restore(noio_flag); |
590347e4 AB |
448 | return ptr; |
449 | } | |
502624bd | 450 | |
88dca4ca | 451 | return __vmalloc(c->block_size, gfp_mask); |
95d402f0 MP |
452 | } |
453 | ||
454 | /* | |
455 | * Free buffer's data. | |
456 | */ | |
457 | static void free_buffer_data(struct dm_bufio_client *c, | |
03b02939 | 458 | void *data, unsigned char data_mode) |
95d402f0 MP |
459 | { |
460 | switch (data_mode) { | |
461 | case DATA_MODE_SLAB: | |
21bb1327 | 462 | kmem_cache_free(c->slab_cache, data); |
95d402f0 MP |
463 | break; |
464 | ||
465 | case DATA_MODE_GET_FREE_PAGES: | |
f51f2e0a MP |
466 | free_pages((unsigned long)data, |
467 | c->sectors_per_block_bits - (PAGE_SHIFT - SECTOR_SHIFT)); | |
95d402f0 MP |
468 | break; |
469 | ||
470 | case DATA_MODE_VMALLOC: | |
471 | vfree(data); | |
472 | break; | |
473 | ||
474 | default: | |
475 | DMCRIT("dm_bufio_free_buffer_data: bad data mode: %d", | |
476 | data_mode); | |
477 | BUG(); | |
478 | } | |
479 | } | |
480 | ||
481 | /* | |
482 | * Allocate buffer and its data. | |
483 | */ | |
484 | static struct dm_buffer *alloc_buffer(struct dm_bufio_client *c, gfp_t gfp_mask) | |
485 | { | |
359dbf19 | 486 | struct dm_buffer *b = kmem_cache_alloc(c->slab_buffer, gfp_mask); |
95d402f0 MP |
487 | |
488 | if (!b) | |
489 | return NULL; | |
490 | ||
491 | b->c = c; | |
492 | ||
493 | b->data = alloc_buffer_data(c, gfp_mask, &b->data_mode); | |
494 | if (!b->data) { | |
359dbf19 | 495 | kmem_cache_free(c->slab_buffer, b); |
95d402f0 MP |
496 | return NULL; |
497 | } | |
498 | ||
86bad0c7 | 499 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
741b58f3 | 500 | b->stack_len = 0; |
86bad0c7 | 501 | #endif |
95d402f0 MP |
502 | return b; |
503 | } | |
504 | ||
505 | /* | |
506 | * Free buffer and its data. | |
507 | */ | |
508 | static void free_buffer(struct dm_buffer *b) | |
509 | { | |
510 | struct dm_bufio_client *c = b->c; | |
511 | ||
95d402f0 | 512 | free_buffer_data(c, b->data, b->data_mode); |
359dbf19 | 513 | kmem_cache_free(c->slab_buffer, b); |
95d402f0 MP |
514 | } |
515 | ||
516 | /* | |
ef992373 | 517 | * Link buffer to the buffer tree and clean or dirty queue. |
95d402f0 MP |
518 | */ |
519 | static void __link_buffer(struct dm_buffer *b, sector_t block, int dirty) | |
520 | { | |
521 | struct dm_bufio_client *c = b->c; | |
522 | ||
523 | c->n_buffers[dirty]++; | |
524 | b->block = block; | |
525 | b->list_mode = dirty; | |
526 | list_add(&b->lru_list, &c->lru[dirty]); | |
4e420c45 | 527 | __insert(b->c, b); |
95d402f0 | 528 | b->last_accessed = jiffies; |
26d2ef0c | 529 | |
d0a328a3 | 530 | adjust_total_allocated(b, false); |
95d402f0 MP |
531 | } |
532 | ||
533 | /* | |
ef992373 | 534 | * Unlink buffer from the buffer tree and dirty or clean queue. |
95d402f0 MP |
535 | */ |
536 | static void __unlink_buffer(struct dm_buffer *b) | |
537 | { | |
538 | struct dm_bufio_client *c = b->c; | |
539 | ||
540 | BUG_ON(!c->n_buffers[b->list_mode]); | |
541 | ||
542 | c->n_buffers[b->list_mode]--; | |
4e420c45 | 543 | __remove(b->c, b); |
95d402f0 | 544 | list_del(&b->lru_list); |
26d2ef0c | 545 | |
d0a328a3 | 546 | adjust_total_allocated(b, true); |
95d402f0 MP |
547 | } |
548 | ||
549 | /* | |
550 | * Place the buffer to the head of dirty or clean LRU queue. | |
551 | */ | |
552 | static void __relink_lru(struct dm_buffer *b, int dirty) | |
553 | { | |
554 | struct dm_bufio_client *c = b->c; | |
555 | ||
6e913b28 MP |
556 | b->accessed = 1; |
557 | ||
95d402f0 MP |
558 | BUG_ON(!c->n_buffers[b->list_mode]); |
559 | ||
560 | c->n_buffers[b->list_mode]--; | |
561 | c->n_buffers[dirty]++; | |
562 | b->list_mode = dirty; | |
54499afb | 563 | list_move(&b->lru_list, &c->lru[dirty]); |
eb76faf5 | 564 | b->last_accessed = jiffies; |
95d402f0 MP |
565 | } |
566 | ||
a4a82ce3 HM |
567 | /* |
568 | *-------------------------------------------------------------------------- | |
95d402f0 MP |
569 | * Submit I/O on the buffer. |
570 | * | |
571 | * Bio interface is faster but it has some problems: | |
572 | * the vector list is limited (increasing this limit increases | |
573 | * memory-consumption per buffer, so it is not viable); | |
574 | * | |
575 | * the memory must be direct-mapped, not vmalloced; | |
576 | * | |
95d402f0 MP |
577 | * If the buffer is small enough (up to DM_BUFIO_INLINE_VECS pages) and |
578 | * it is not vmalloced, try using the bio interface. | |
579 | * | |
580 | * If the buffer is big, if it is vmalloced or if the underlying device | |
581 | * rejects the bio because it is too large, use dm-io layer to do the I/O. | |
582 | * The dm-io layer splits the I/O into multiple requests, avoiding the above | |
583 | * shortcomings. | |
a4a82ce3 HM |
584 | *-------------------------------------------------------------------------- |
585 | */ | |
95d402f0 MP |
586 | |
587 | /* | |
588 | * dm-io completion routine. It just calls b->bio.bi_end_io, pretending | |
589 | * that the request was handled directly with bio interface. | |
590 | */ | |
591 | static void dmio_complete(unsigned long error, void *context) | |
592 | { | |
593 | struct dm_buffer *b = context; | |
594 | ||
45354f1e | 595 | b->end_io(b, unlikely(error != 0) ? BLK_STS_IOERR : 0); |
95d402f0 MP |
596 | } |
597 | ||
a3282b43 | 598 | static void use_dmio(struct dm_buffer *b, enum req_op op, sector_t sector, |
86a3238c | 599 | unsigned int n_sectors, unsigned int offset) |
95d402f0 MP |
600 | { |
601 | int r; | |
602 | struct dm_io_request io_req = { | |
a3282b43 | 603 | .bi_opf = op, |
95d402f0 MP |
604 | .notify.fn = dmio_complete, |
605 | .notify.context = b, | |
606 | .client = b->c->dm_io, | |
607 | }; | |
608 | struct dm_io_region region = { | |
609 | .bdev = b->c->bdev, | |
400a0bef MP |
610 | .sector = sector, |
611 | .count = n_sectors, | |
95d402f0 MP |
612 | }; |
613 | ||
614 | if (b->data_mode != DATA_MODE_VMALLOC) { | |
615 | io_req.mem.type = DM_IO_KMEM; | |
1e3b21c6 | 616 | io_req.mem.ptr.addr = (char *)b->data + offset; |
95d402f0 MP |
617 | } else { |
618 | io_req.mem.type = DM_IO_VMA; | |
1e3b21c6 | 619 | io_req.mem.ptr.vma = (char *)b->data + offset; |
95d402f0 MP |
620 | } |
621 | ||
95d402f0 | 622 | r = dm_io(&io_req, 1, ®ion, NULL); |
45354f1e MP |
623 | if (unlikely(r)) |
624 | b->end_io(b, errno_to_blk_status(r)); | |
95d402f0 MP |
625 | } |
626 | ||
45354f1e | 627 | static void bio_complete(struct bio *bio) |
445559cd | 628 | { |
45354f1e | 629 | struct dm_buffer *b = bio->bi_private; |
4e4cbee9 | 630 | blk_status_t status = bio->bi_status; |
0ef0b471 | 631 | |
066ff571 CH |
632 | bio_uninit(bio); |
633 | kfree(bio); | |
45354f1e | 634 | b->end_io(b, status); |
445559cd DW |
635 | } |
636 | ||
a3282b43 | 637 | static void use_bio(struct dm_buffer *b, enum req_op op, sector_t sector, |
86a3238c | 638 | unsigned int n_sectors, unsigned int offset) |
95d402f0 | 639 | { |
45354f1e | 640 | struct bio *bio; |
95d402f0 | 641 | char *ptr; |
86a3238c | 642 | unsigned int vec_size, len; |
95d402f0 | 643 | |
45354f1e MP |
644 | vec_size = b->c->block_size >> PAGE_SHIFT; |
645 | if (unlikely(b->c->sectors_per_block_bits < PAGE_SHIFT - SECTOR_SHIFT)) | |
646 | vec_size += 2; | |
647 | ||
066ff571 | 648 | bio = bio_kmalloc(vec_size, GFP_NOWAIT | __GFP_NORETRY | __GFP_NOWARN); |
45354f1e MP |
649 | if (!bio) { |
650 | dmio: | |
a3282b43 | 651 | use_dmio(b, op, sector, n_sectors, offset); |
45354f1e MP |
652 | return; |
653 | } | |
a3282b43 | 654 | bio_init(bio, b->c->bdev, bio->bi_inline_vecs, vec_size, op); |
45354f1e | 655 | bio->bi_iter.bi_sector = sector; |
45354f1e MP |
656 | bio->bi_end_io = bio_complete; |
657 | bio->bi_private = b; | |
95d402f0 | 658 | |
1e3b21c6 | 659 | ptr = (char *)b->data + offset; |
400a0bef | 660 | len = n_sectors << SECTOR_SHIFT; |
95d402f0 | 661 | |
95d402f0 | 662 | do { |
86a3238c | 663 | unsigned int this_step = min((unsigned int)(PAGE_SIZE - offset_in_page(ptr)), len); |
0ef0b471 | 664 | |
45354f1e | 665 | if (!bio_add_page(bio, virt_to_page(ptr), this_step, |
756d097b | 666 | offset_in_page(ptr))) { |
45354f1e MP |
667 | bio_put(bio); |
668 | goto dmio; | |
95d402f0 MP |
669 | } |
670 | ||
1e3b21c6 MP |
671 | len -= this_step; |
672 | ptr += this_step; | |
95d402f0 MP |
673 | } while (len > 0); |
674 | ||
45354f1e | 675 | submit_bio(bio); |
95d402f0 MP |
676 | } |
677 | ||
6fbeb004 MP |
678 | static inline sector_t block_to_sector(struct dm_bufio_client *c, sector_t block) |
679 | { | |
680 | sector_t sector; | |
681 | ||
682 | if (likely(c->sectors_per_block_bits >= 0)) | |
683 | sector = block << c->sectors_per_block_bits; | |
684 | else | |
685 | sector = block * (c->block_size >> SECTOR_SHIFT); | |
686 | sector += c->start; | |
687 | ||
688 | return sector; | |
689 | } | |
690 | ||
a3282b43 BVA |
691 | static void submit_io(struct dm_buffer *b, enum req_op op, |
692 | void (*end_io)(struct dm_buffer *, blk_status_t)) | |
95d402f0 | 693 | { |
86a3238c | 694 | unsigned int n_sectors; |
400a0bef | 695 | sector_t sector; |
86a3238c | 696 | unsigned int offset, end; |
95d402f0 | 697 | |
45354f1e MP |
698 | b->end_io = end_io; |
699 | ||
6fbeb004 | 700 | sector = block_to_sector(b->c, b->block); |
1e3b21c6 | 701 | |
a3282b43 | 702 | if (op != REQ_OP_WRITE) { |
f51f2e0a | 703 | n_sectors = b->c->block_size >> SECTOR_SHIFT; |
1e3b21c6 MP |
704 | offset = 0; |
705 | } else { | |
706 | if (b->c->write_callback) | |
707 | b->c->write_callback(b); | |
708 | offset = b->write_start; | |
709 | end = b->write_end; | |
710 | offset &= -DM_BUFIO_WRITE_ALIGN; | |
711 | end += DM_BUFIO_WRITE_ALIGN - 1; | |
712 | end &= -DM_BUFIO_WRITE_ALIGN; | |
713 | if (unlikely(end > b->c->block_size)) | |
714 | end = b->c->block_size; | |
715 | ||
716 | sector += offset >> SECTOR_SHIFT; | |
717 | n_sectors = (end - offset) >> SECTOR_SHIFT; | |
718 | } | |
400a0bef | 719 | |
45354f1e | 720 | if (b->data_mode != DATA_MODE_VMALLOC) |
a3282b43 | 721 | use_bio(b, op, sector, n_sectors, offset); |
95d402f0 | 722 | else |
a3282b43 | 723 | use_dmio(b, op, sector, n_sectors, offset); |
95d402f0 MP |
724 | } |
725 | ||
a4a82ce3 HM |
726 | /* |
727 | *-------------------------------------------------------------- | |
95d402f0 | 728 | * Writing dirty buffers |
a4a82ce3 HM |
729 | *-------------------------------------------------------------- |
730 | */ | |
95d402f0 MP |
731 | |
732 | /* | |
733 | * The endio routine for write. | |
734 | * | |
735 | * Set the error, clear B_WRITING bit and wake anyone who was waiting on | |
736 | * it. | |
737 | */ | |
45354f1e | 738 | static void write_endio(struct dm_buffer *b, blk_status_t status) |
95d402f0 | 739 | { |
45354f1e MP |
740 | b->write_error = status; |
741 | if (unlikely(status)) { | |
95d402f0 | 742 | struct dm_bufio_client *c = b->c; |
4e4cbee9 CH |
743 | |
744 | (void)cmpxchg(&c->async_write_error, 0, | |
45354f1e | 745 | blk_status_to_errno(status)); |
95d402f0 MP |
746 | } |
747 | ||
748 | BUG_ON(!test_bit(B_WRITING, &b->state)); | |
749 | ||
4e857c58 | 750 | smp_mb__before_atomic(); |
95d402f0 | 751 | clear_bit(B_WRITING, &b->state); |
4e857c58 | 752 | smp_mb__after_atomic(); |
95d402f0 MP |
753 | |
754 | wake_up_bit(&b->state, B_WRITING); | |
755 | } | |
756 | ||
95d402f0 MP |
757 | /* |
758 | * Initiate a write on a dirty buffer, but don't wait for it. | |
759 | * | |
760 | * - If the buffer is not dirty, exit. | |
761 | * - If there some previous write going on, wait for it to finish (we can't | |
762 | * have two writes on the same buffer simultaneously). | |
763 | * - Submit our write and don't wait on it. We set B_WRITING indicating | |
764 | * that there is a write in progress. | |
765 | */ | |
2480945c MP |
766 | static void __write_dirty_buffer(struct dm_buffer *b, |
767 | struct list_head *write_list) | |
95d402f0 MP |
768 | { |
769 | if (!test_bit(B_DIRTY, &b->state)) | |
770 | return; | |
771 | ||
772 | clear_bit(B_DIRTY, &b->state); | |
74316201 | 773 | wait_on_bit_lock_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE); |
95d402f0 | 774 | |
1e3b21c6 MP |
775 | b->write_start = b->dirty_start; |
776 | b->write_end = b->dirty_end; | |
777 | ||
2480945c | 778 | if (!write_list) |
905be0a1 | 779 | submit_io(b, REQ_OP_WRITE, write_endio); |
2480945c MP |
780 | else |
781 | list_add_tail(&b->write_list, write_list); | |
782 | } | |
783 | ||
784 | static void __flush_write_list(struct list_head *write_list) | |
785 | { | |
786 | struct blk_plug plug; | |
0ef0b471 | 787 | |
2480945c MP |
788 | blk_start_plug(&plug); |
789 | while (!list_empty(write_list)) { | |
790 | struct dm_buffer *b = | |
791 | list_entry(write_list->next, struct dm_buffer, write_list); | |
792 | list_del(&b->write_list); | |
905be0a1 | 793 | submit_io(b, REQ_OP_WRITE, write_endio); |
7cd32674 | 794 | cond_resched(); |
2480945c MP |
795 | } |
796 | blk_finish_plug(&plug); | |
95d402f0 MP |
797 | } |
798 | ||
799 | /* | |
800 | * Wait until any activity on the buffer finishes. Possibly write the | |
801 | * buffer if it is dirty. When this function finishes, there is no I/O | |
802 | * running on the buffer and the buffer is not dirty. | |
803 | */ | |
804 | static void __make_buffer_clean(struct dm_buffer *b) | |
805 | { | |
806 | BUG_ON(b->hold_count); | |
807 | ||
141b3523 MP |
808 | /* smp_load_acquire() pairs with read_endio()'s smp_mb__before_atomic() */ |
809 | if (!smp_load_acquire(&b->state)) /* fast case */ | |
95d402f0 MP |
810 | return; |
811 | ||
74316201 | 812 | wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE); |
2480945c | 813 | __write_dirty_buffer(b, NULL); |
74316201 | 814 | wait_on_bit_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE); |
95d402f0 MP |
815 | } |
816 | ||
817 | /* | |
818 | * Find some buffer that is not held by anybody, clean it, unlink it and | |
819 | * return it. | |
820 | */ | |
821 | static struct dm_buffer *__get_unclaimed_buffer(struct dm_bufio_client *c) | |
822 | { | |
823 | struct dm_buffer *b; | |
824 | ||
825 | list_for_each_entry_reverse(b, &c->lru[LIST_CLEAN], lru_list) { | |
826 | BUG_ON(test_bit(B_WRITING, &b->state)); | |
827 | BUG_ON(test_bit(B_DIRTY, &b->state)); | |
828 | ||
e3a7c294 | 829 | if (static_branch_unlikely(&no_sleep_enabled) && c->no_sleep && |
141b3523 | 830 | unlikely(test_bit_acquire(B_READING, &b->state))) |
e3a7c294 MP |
831 | continue; |
832 | ||
95d402f0 MP |
833 | if (!b->hold_count) { |
834 | __make_buffer_clean(b); | |
835 | __unlink_buffer(b); | |
836 | return b; | |
837 | } | |
7cd32674 | 838 | cond_resched(); |
95d402f0 MP |
839 | } |
840 | ||
e3a7c294 MP |
841 | if (static_branch_unlikely(&no_sleep_enabled) && c->no_sleep) |
842 | return NULL; | |
843 | ||
95d402f0 MP |
844 | list_for_each_entry_reverse(b, &c->lru[LIST_DIRTY], lru_list) { |
845 | BUG_ON(test_bit(B_READING, &b->state)); | |
846 | ||
847 | if (!b->hold_count) { | |
848 | __make_buffer_clean(b); | |
849 | __unlink_buffer(b); | |
850 | return b; | |
851 | } | |
7cd32674 | 852 | cond_resched(); |
95d402f0 MP |
853 | } |
854 | ||
855 | return NULL; | |
856 | } | |
857 | ||
858 | /* | |
859 | * Wait until some other threads free some buffer or release hold count on | |
860 | * some buffer. | |
861 | * | |
862 | * This function is entered with c->lock held, drops it and regains it | |
863 | * before exiting. | |
864 | */ | |
865 | static void __wait_for_free_buffer(struct dm_bufio_client *c) | |
866 | { | |
867 | DECLARE_WAITQUEUE(wait, current); | |
868 | ||
869 | add_wait_queue(&c->free_buffer_wait, &wait); | |
642fa448 | 870 | set_current_state(TASK_UNINTERRUPTIBLE); |
95d402f0 MP |
871 | dm_bufio_unlock(c); |
872 | ||
873 | io_schedule(); | |
874 | ||
95d402f0 MP |
875 | remove_wait_queue(&c->free_buffer_wait, &wait); |
876 | ||
877 | dm_bufio_lock(c); | |
878 | } | |
879 | ||
a66cc28f MP |
880 | enum new_flag { |
881 | NF_FRESH = 0, | |
882 | NF_READ = 1, | |
883 | NF_GET = 2, | |
884 | NF_PREFETCH = 3 | |
885 | }; | |
886 | ||
95d402f0 MP |
887 | /* |
888 | * Allocate a new buffer. If the allocation is not possible, wait until | |
889 | * some other thread frees a buffer. | |
890 | * | |
891 | * May drop the lock and regain it. | |
892 | */ | |
a66cc28f | 893 | static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client *c, enum new_flag nf) |
95d402f0 MP |
894 | { |
895 | struct dm_buffer *b; | |
41c73a49 | 896 | bool tried_noio_alloc = false; |
95d402f0 MP |
897 | |
898 | /* | |
899 | * dm-bufio is resistant to allocation failures (it just keeps | |
900 | * one buffer reserved in cases all the allocations fail). | |
901 | * So set flags to not try too hard: | |
9ea61cac DA |
902 | * GFP_NOWAIT: don't wait; if we need to sleep we'll release our |
903 | * mutex and wait ourselves. | |
95d402f0 MP |
904 | * __GFP_NORETRY: don't retry and rather return failure |
905 | * __GFP_NOMEMALLOC: don't use emergency reserves | |
906 | * __GFP_NOWARN: don't print a warning in case of failure | |
907 | * | |
908 | * For debugging, if we set the cache size to 1, no new buffers will | |
909 | * be allocated. | |
910 | */ | |
911 | while (1) { | |
912 | if (dm_bufio_cache_size_latch != 1) { | |
9ea61cac | 913 | b = alloc_buffer(c, GFP_NOWAIT | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); |
95d402f0 MP |
914 | if (b) |
915 | return b; | |
916 | } | |
917 | ||
a66cc28f MP |
918 | if (nf == NF_PREFETCH) |
919 | return NULL; | |
920 | ||
41c73a49 MP |
921 | if (dm_bufio_cache_size_latch != 1 && !tried_noio_alloc) { |
922 | dm_bufio_unlock(c); | |
923 | b = alloc_buffer(c, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); | |
924 | dm_bufio_lock(c); | |
925 | if (b) | |
926 | return b; | |
927 | tried_noio_alloc = true; | |
928 | } | |
929 | ||
95d402f0 MP |
930 | if (!list_empty(&c->reserved_buffers)) { |
931 | b = list_entry(c->reserved_buffers.next, | |
932 | struct dm_buffer, lru_list); | |
933 | list_del(&b->lru_list); | |
934 | c->need_reserved_buffers++; | |
935 | ||
936 | return b; | |
937 | } | |
938 | ||
939 | b = __get_unclaimed_buffer(c); | |
940 | if (b) | |
941 | return b; | |
942 | ||
943 | __wait_for_free_buffer(c); | |
944 | } | |
945 | } | |
946 | ||
a66cc28f | 947 | static struct dm_buffer *__alloc_buffer_wait(struct dm_bufio_client *c, enum new_flag nf) |
95d402f0 | 948 | { |
a66cc28f MP |
949 | struct dm_buffer *b = __alloc_buffer_wait_no_callback(c, nf); |
950 | ||
951 | if (!b) | |
952 | return NULL; | |
95d402f0 MP |
953 | |
954 | if (c->alloc_callback) | |
955 | c->alloc_callback(b); | |
956 | ||
957 | return b; | |
958 | } | |
959 | ||
960 | /* | |
961 | * Free a buffer and wake other threads waiting for free buffers. | |
962 | */ | |
963 | static void __free_buffer_wake(struct dm_buffer *b) | |
964 | { | |
965 | struct dm_bufio_client *c = b->c; | |
966 | ||
967 | if (!c->need_reserved_buffers) | |
968 | free_buffer(b); | |
969 | else { | |
970 | list_add(&b->lru_list, &c->reserved_buffers); | |
971 | c->need_reserved_buffers--; | |
972 | } | |
973 | ||
974 | wake_up(&c->free_buffer_wait); | |
975 | } | |
976 | ||
2480945c MP |
977 | static void __write_dirty_buffers_async(struct dm_bufio_client *c, int no_wait, |
978 | struct list_head *write_list) | |
95d402f0 MP |
979 | { |
980 | struct dm_buffer *b, *tmp; | |
981 | ||
982 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { | |
983 | BUG_ON(test_bit(B_READING, &b->state)); | |
984 | ||
985 | if (!test_bit(B_DIRTY, &b->state) && | |
986 | !test_bit(B_WRITING, &b->state)) { | |
987 | __relink_lru(b, LIST_CLEAN); | |
988 | continue; | |
989 | } | |
990 | ||
991 | if (no_wait && test_bit(B_WRITING, &b->state)) | |
992 | return; | |
993 | ||
2480945c | 994 | __write_dirty_buffer(b, write_list); |
7cd32674 | 995 | cond_resched(); |
95d402f0 MP |
996 | } |
997 | } | |
998 | ||
95d402f0 MP |
999 | /* |
1000 | * Check if we're over watermark. | |
1001 | * If we are over threshold_buffers, start freeing buffers. | |
1002 | * If we're over "limit_buffers", block until we get under the limit. | |
1003 | */ | |
2480945c MP |
1004 | static void __check_watermark(struct dm_bufio_client *c, |
1005 | struct list_head *write_list) | |
95d402f0 | 1006 | { |
b132ff33 | 1007 | if (c->n_buffers[LIST_DIRTY] > c->n_buffers[LIST_CLEAN] * DM_BUFIO_WRITEBACK_RATIO) |
2480945c | 1008 | __write_dirty_buffers_async(c, 1, write_list); |
95d402f0 MP |
1009 | } |
1010 | ||
a4a82ce3 HM |
1011 | /* |
1012 | *-------------------------------------------------------------- | |
95d402f0 | 1013 | * Getting a buffer |
a4a82ce3 HM |
1014 | *-------------------------------------------------------------- |
1015 | */ | |
95d402f0 | 1016 | |
95d402f0 | 1017 | static struct dm_buffer *__bufio_new(struct dm_bufio_client *c, sector_t block, |
2480945c MP |
1018 | enum new_flag nf, int *need_submit, |
1019 | struct list_head *write_list) | |
95d402f0 MP |
1020 | { |
1021 | struct dm_buffer *b, *new_b = NULL; | |
1022 | ||
1023 | *need_submit = 0; | |
1024 | ||
1025 | b = __find(c, block); | |
a66cc28f MP |
1026 | if (b) |
1027 | goto found_buffer; | |
95d402f0 MP |
1028 | |
1029 | if (nf == NF_GET) | |
1030 | return NULL; | |
1031 | ||
a66cc28f MP |
1032 | new_b = __alloc_buffer_wait(c, nf); |
1033 | if (!new_b) | |
1034 | return NULL; | |
95d402f0 MP |
1035 | |
1036 | /* | |
1037 | * We've had a period where the mutex was unlocked, so need to | |
ef992373 | 1038 | * recheck the buffer tree. |
95d402f0 MP |
1039 | */ |
1040 | b = __find(c, block); | |
1041 | if (b) { | |
1042 | __free_buffer_wake(new_b); | |
a66cc28f | 1043 | goto found_buffer; |
95d402f0 MP |
1044 | } |
1045 | ||
2480945c | 1046 | __check_watermark(c, write_list); |
95d402f0 MP |
1047 | |
1048 | b = new_b; | |
1049 | b->hold_count = 1; | |
1050 | b->read_error = 0; | |
1051 | b->write_error = 0; | |
1052 | __link_buffer(b, block, LIST_CLEAN); | |
1053 | ||
1054 | if (nf == NF_FRESH) { | |
1055 | b->state = 0; | |
1056 | return b; | |
1057 | } | |
1058 | ||
1059 | b->state = 1 << B_READING; | |
1060 | *need_submit = 1; | |
1061 | ||
1062 | return b; | |
a66cc28f MP |
1063 | |
1064 | found_buffer: | |
1065 | if (nf == NF_PREFETCH) | |
1066 | return NULL; | |
1067 | /* | |
1068 | * Note: it is essential that we don't wait for the buffer to be | |
1069 | * read if dm_bufio_get function is used. Both dm_bufio_get and | |
1070 | * dm_bufio_prefetch can be used in the driver request routine. | |
1071 | * If the user called both dm_bufio_prefetch and dm_bufio_get on | |
1072 | * the same buffer, it would deadlock if we waited. | |
1073 | */ | |
141b3523 | 1074 | if (nf == NF_GET && unlikely(test_bit_acquire(B_READING, &b->state))) |
a66cc28f MP |
1075 | return NULL; |
1076 | ||
1077 | b->hold_count++; | |
1078 | __relink_lru(b, test_bit(B_DIRTY, &b->state) || | |
1079 | test_bit(B_WRITING, &b->state)); | |
1080 | return b; | |
95d402f0 MP |
1081 | } |
1082 | ||
1083 | /* | |
1084 | * The endio routine for reading: set the error, clear the bit and wake up | |
1085 | * anyone waiting on the buffer. | |
1086 | */ | |
45354f1e | 1087 | static void read_endio(struct dm_buffer *b, blk_status_t status) |
95d402f0 | 1088 | { |
45354f1e | 1089 | b->read_error = status; |
95d402f0 MP |
1090 | |
1091 | BUG_ON(!test_bit(B_READING, &b->state)); | |
1092 | ||
4e857c58 | 1093 | smp_mb__before_atomic(); |
95d402f0 | 1094 | clear_bit(B_READING, &b->state); |
4e857c58 | 1095 | smp_mb__after_atomic(); |
95d402f0 MP |
1096 | |
1097 | wake_up_bit(&b->state, B_READING); | |
1098 | } | |
1099 | ||
1100 | /* | |
1101 | * A common routine for dm_bufio_new and dm_bufio_read. Operation of these | |
1102 | * functions is similar except that dm_bufio_new doesn't read the | |
1103 | * buffer from the disk (assuming that the caller overwrites all the data | |
1104 | * and uses dm_bufio_mark_buffer_dirty to write new data back). | |
1105 | */ | |
1106 | static void *new_read(struct dm_bufio_client *c, sector_t block, | |
1107 | enum new_flag nf, struct dm_buffer **bp) | |
1108 | { | |
1109 | int need_submit; | |
1110 | struct dm_buffer *b; | |
1111 | ||
2480945c MP |
1112 | LIST_HEAD(write_list); |
1113 | ||
95d402f0 | 1114 | dm_bufio_lock(c); |
2480945c | 1115 | b = __bufio_new(c, block, nf, &need_submit, &write_list); |
86bad0c7 MP |
1116 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
1117 | if (b && b->hold_count == 1) | |
1118 | buffer_record_stack(b); | |
1119 | #endif | |
95d402f0 MP |
1120 | dm_bufio_unlock(c); |
1121 | ||
2480945c MP |
1122 | __flush_write_list(&write_list); |
1123 | ||
a66cc28f | 1124 | if (!b) |
f98c8f79 | 1125 | return NULL; |
95d402f0 MP |
1126 | |
1127 | if (need_submit) | |
905be0a1 | 1128 | submit_io(b, REQ_OP_READ, read_endio); |
95d402f0 | 1129 | |
74316201 | 1130 | wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE); |
95d402f0 MP |
1131 | |
1132 | if (b->read_error) { | |
4e4cbee9 | 1133 | int error = blk_status_to_errno(b->read_error); |
95d402f0 MP |
1134 | |
1135 | dm_bufio_release(b); | |
1136 | ||
1137 | return ERR_PTR(error); | |
1138 | } | |
1139 | ||
1140 | *bp = b; | |
1141 | ||
1142 | return b->data; | |
1143 | } | |
1144 | ||
1145 | void *dm_bufio_get(struct dm_bufio_client *c, sector_t block, | |
1146 | struct dm_buffer **bp) | |
1147 | { | |
1148 | return new_read(c, block, NF_GET, bp); | |
1149 | } | |
1150 | EXPORT_SYMBOL_GPL(dm_bufio_get); | |
1151 | ||
1152 | void *dm_bufio_read(struct dm_bufio_client *c, sector_t block, | |
1153 | struct dm_buffer **bp) | |
1154 | { | |
1155 | BUG_ON(dm_bufio_in_request()); | |
1156 | ||
1157 | return new_read(c, block, NF_READ, bp); | |
1158 | } | |
1159 | EXPORT_SYMBOL_GPL(dm_bufio_read); | |
1160 | ||
1161 | void *dm_bufio_new(struct dm_bufio_client *c, sector_t block, | |
1162 | struct dm_buffer **bp) | |
1163 | { | |
1164 | BUG_ON(dm_bufio_in_request()); | |
1165 | ||
1166 | return new_read(c, block, NF_FRESH, bp); | |
1167 | } | |
1168 | EXPORT_SYMBOL_GPL(dm_bufio_new); | |
1169 | ||
a66cc28f | 1170 | void dm_bufio_prefetch(struct dm_bufio_client *c, |
86a3238c | 1171 | sector_t block, unsigned int n_blocks) |
a66cc28f MP |
1172 | { |
1173 | struct blk_plug plug; | |
1174 | ||
2480945c MP |
1175 | LIST_HEAD(write_list); |
1176 | ||
3b6b7813 MP |
1177 | BUG_ON(dm_bufio_in_request()); |
1178 | ||
a66cc28f MP |
1179 | blk_start_plug(&plug); |
1180 | dm_bufio_lock(c); | |
1181 | ||
1182 | for (; n_blocks--; block++) { | |
1183 | int need_submit; | |
1184 | struct dm_buffer *b; | |
0ef0b471 | 1185 | |
2480945c MP |
1186 | b = __bufio_new(c, block, NF_PREFETCH, &need_submit, |
1187 | &write_list); | |
1188 | if (unlikely(!list_empty(&write_list))) { | |
1189 | dm_bufio_unlock(c); | |
1190 | blk_finish_plug(&plug); | |
1191 | __flush_write_list(&write_list); | |
1192 | blk_start_plug(&plug); | |
1193 | dm_bufio_lock(c); | |
1194 | } | |
a66cc28f MP |
1195 | if (unlikely(b != NULL)) { |
1196 | dm_bufio_unlock(c); | |
1197 | ||
1198 | if (need_submit) | |
905be0a1 | 1199 | submit_io(b, REQ_OP_READ, read_endio); |
a66cc28f MP |
1200 | dm_bufio_release(b); |
1201 | ||
7cd32674 | 1202 | cond_resched(); |
a66cc28f MP |
1203 | |
1204 | if (!n_blocks) | |
1205 | goto flush_plug; | |
1206 | dm_bufio_lock(c); | |
1207 | } | |
a66cc28f MP |
1208 | } |
1209 | ||
1210 | dm_bufio_unlock(c); | |
1211 | ||
1212 | flush_plug: | |
1213 | blk_finish_plug(&plug); | |
1214 | } | |
1215 | EXPORT_SYMBOL_GPL(dm_bufio_prefetch); | |
1216 | ||
95d402f0 MP |
1217 | void dm_bufio_release(struct dm_buffer *b) |
1218 | { | |
1219 | struct dm_bufio_client *c = b->c; | |
1220 | ||
1221 | dm_bufio_lock(c); | |
1222 | ||
95d402f0 MP |
1223 | BUG_ON(!b->hold_count); |
1224 | ||
1225 | b->hold_count--; | |
1226 | if (!b->hold_count) { | |
1227 | wake_up(&c->free_buffer_wait); | |
1228 | ||
1229 | /* | |
1230 | * If there were errors on the buffer, and the buffer is not | |
1231 | * to be written, free the buffer. There is no point in caching | |
1232 | * invalid buffer. | |
1233 | */ | |
1234 | if ((b->read_error || b->write_error) && | |
141b3523 | 1235 | !test_bit_acquire(B_READING, &b->state) && |
95d402f0 MP |
1236 | !test_bit(B_WRITING, &b->state) && |
1237 | !test_bit(B_DIRTY, &b->state)) { | |
1238 | __unlink_buffer(b); | |
1239 | __free_buffer_wake(b); | |
1240 | } | |
1241 | } | |
1242 | ||
1243 | dm_bufio_unlock(c); | |
1244 | } | |
1245 | EXPORT_SYMBOL_GPL(dm_bufio_release); | |
1246 | ||
1e3b21c6 | 1247 | void dm_bufio_mark_partial_buffer_dirty(struct dm_buffer *b, |
86a3238c | 1248 | unsigned int start, unsigned int end) |
95d402f0 MP |
1249 | { |
1250 | struct dm_bufio_client *c = b->c; | |
1251 | ||
1e3b21c6 MP |
1252 | BUG_ON(start >= end); |
1253 | BUG_ON(end > b->c->block_size); | |
1254 | ||
95d402f0 MP |
1255 | dm_bufio_lock(c); |
1256 | ||
a66cc28f MP |
1257 | BUG_ON(test_bit(B_READING, &b->state)); |
1258 | ||
1e3b21c6 MP |
1259 | if (!test_and_set_bit(B_DIRTY, &b->state)) { |
1260 | b->dirty_start = start; | |
1261 | b->dirty_end = end; | |
95d402f0 | 1262 | __relink_lru(b, LIST_DIRTY); |
1e3b21c6 MP |
1263 | } else { |
1264 | if (start < b->dirty_start) | |
1265 | b->dirty_start = start; | |
1266 | if (end > b->dirty_end) | |
1267 | b->dirty_end = end; | |
1268 | } | |
95d402f0 MP |
1269 | |
1270 | dm_bufio_unlock(c); | |
1271 | } | |
1e3b21c6 MP |
1272 | EXPORT_SYMBOL_GPL(dm_bufio_mark_partial_buffer_dirty); |
1273 | ||
1274 | void dm_bufio_mark_buffer_dirty(struct dm_buffer *b) | |
1275 | { | |
1276 | dm_bufio_mark_partial_buffer_dirty(b, 0, b->c->block_size); | |
1277 | } | |
95d402f0 MP |
1278 | EXPORT_SYMBOL_GPL(dm_bufio_mark_buffer_dirty); |
1279 | ||
1280 | void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c) | |
1281 | { | |
2480945c MP |
1282 | LIST_HEAD(write_list); |
1283 | ||
95d402f0 MP |
1284 | BUG_ON(dm_bufio_in_request()); |
1285 | ||
1286 | dm_bufio_lock(c); | |
2480945c | 1287 | __write_dirty_buffers_async(c, 0, &write_list); |
95d402f0 | 1288 | dm_bufio_unlock(c); |
2480945c | 1289 | __flush_write_list(&write_list); |
95d402f0 MP |
1290 | } |
1291 | EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers_async); | |
1292 | ||
1293 | /* | |
1294 | * For performance, it is essential that the buffers are written asynchronously | |
1295 | * and simultaneously (so that the block layer can merge the writes) and then | |
1296 | * waited upon. | |
1297 | * | |
1298 | * Finally, we flush hardware disk cache. | |
1299 | */ | |
1300 | int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c) | |
1301 | { | |
edc11d49 | 1302 | int a, f; |
95d402f0 MP |
1303 | unsigned long buffers_processed = 0; |
1304 | struct dm_buffer *b, *tmp; | |
1305 | ||
2480945c MP |
1306 | LIST_HEAD(write_list); |
1307 | ||
1308 | dm_bufio_lock(c); | |
1309 | __write_dirty_buffers_async(c, 0, &write_list); | |
1310 | dm_bufio_unlock(c); | |
1311 | __flush_write_list(&write_list); | |
95d402f0 | 1312 | dm_bufio_lock(c); |
95d402f0 MP |
1313 | |
1314 | again: | |
1315 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { | |
1316 | int dropped_lock = 0; | |
1317 | ||
1318 | if (buffers_processed < c->n_buffers[LIST_DIRTY]) | |
1319 | buffers_processed++; | |
1320 | ||
1321 | BUG_ON(test_bit(B_READING, &b->state)); | |
1322 | ||
1323 | if (test_bit(B_WRITING, &b->state)) { | |
1324 | if (buffers_processed < c->n_buffers[LIST_DIRTY]) { | |
1325 | dropped_lock = 1; | |
1326 | b->hold_count++; | |
1327 | dm_bufio_unlock(c); | |
74316201 N |
1328 | wait_on_bit_io(&b->state, B_WRITING, |
1329 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1330 | dm_bufio_lock(c); |
1331 | b->hold_count--; | |
1332 | } else | |
74316201 N |
1333 | wait_on_bit_io(&b->state, B_WRITING, |
1334 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1335 | } |
1336 | ||
1337 | if (!test_bit(B_DIRTY, &b->state) && | |
1338 | !test_bit(B_WRITING, &b->state)) | |
1339 | __relink_lru(b, LIST_CLEAN); | |
1340 | ||
7cd32674 | 1341 | cond_resched(); |
95d402f0 MP |
1342 | |
1343 | /* | |
1344 | * If we dropped the lock, the list is no longer consistent, | |
1345 | * so we must restart the search. | |
1346 | * | |
1347 | * In the most common case, the buffer just processed is | |
1348 | * relinked to the clean list, so we won't loop scanning the | |
1349 | * same buffer again and again. | |
1350 | * | |
1351 | * This may livelock if there is another thread simultaneously | |
1352 | * dirtying buffers, so we count the number of buffers walked | |
1353 | * and if it exceeds the total number of buffers, it means that | |
1354 | * someone is doing some writes simultaneously with us. In | |
1355 | * this case, stop, dropping the lock. | |
1356 | */ | |
1357 | if (dropped_lock) | |
1358 | goto again; | |
1359 | } | |
1360 | wake_up(&c->free_buffer_wait); | |
1361 | dm_bufio_unlock(c); | |
1362 | ||
1363 | a = xchg(&c->async_write_error, 0); | |
1364 | f = dm_bufio_issue_flush(c); | |
1365 | if (a) | |
1366 | return a; | |
1367 | ||
1368 | return f; | |
1369 | } | |
1370 | EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers); | |
1371 | ||
1372 | /* | |
ef992373 | 1373 | * Use dm-io to send an empty barrier to flush the device. |
95d402f0 MP |
1374 | */ |
1375 | int dm_bufio_issue_flush(struct dm_bufio_client *c) | |
1376 | { | |
1377 | struct dm_io_request io_req = { | |
581075e4 | 1378 | .bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC, |
95d402f0 MP |
1379 | .mem.type = DM_IO_KMEM, |
1380 | .mem.ptr.addr = NULL, | |
1381 | .client = c->dm_io, | |
1382 | }; | |
1383 | struct dm_io_region io_reg = { | |
1384 | .bdev = c->bdev, | |
1385 | .sector = 0, | |
1386 | .count = 0, | |
1387 | }; | |
1388 | ||
1389 | BUG_ON(dm_bufio_in_request()); | |
1390 | ||
1391 | return dm_io(&io_req, 1, &io_reg, NULL); | |
1392 | } | |
1393 | EXPORT_SYMBOL_GPL(dm_bufio_issue_flush); | |
1394 | ||
6fbeb004 MP |
1395 | /* |
1396 | * Use dm-io to send a discard request to flush the device. | |
1397 | */ | |
1398 | int dm_bufio_issue_discard(struct dm_bufio_client *c, sector_t block, sector_t count) | |
1399 | { | |
1400 | struct dm_io_request io_req = { | |
581075e4 | 1401 | .bi_opf = REQ_OP_DISCARD | REQ_SYNC, |
6fbeb004 MP |
1402 | .mem.type = DM_IO_KMEM, |
1403 | .mem.ptr.addr = NULL, | |
1404 | .client = c->dm_io, | |
1405 | }; | |
1406 | struct dm_io_region io_reg = { | |
1407 | .bdev = c->bdev, | |
1408 | .sector = block_to_sector(c, block), | |
1409 | .count = block_to_sector(c, count), | |
1410 | }; | |
1411 | ||
1412 | BUG_ON(dm_bufio_in_request()); | |
1413 | ||
1414 | return dm_io(&io_req, 1, &io_reg, NULL); | |
1415 | } | |
1416 | EXPORT_SYMBOL_GPL(dm_bufio_issue_discard); | |
1417 | ||
95d402f0 MP |
1418 | /* |
1419 | * We first delete any other buffer that may be at that new location. | |
1420 | * | |
1421 | * Then, we write the buffer to the original location if it was dirty. | |
1422 | * | |
1423 | * Then, if we are the only one who is holding the buffer, relink the buffer | |
ef992373 | 1424 | * in the buffer tree for the new location. |
95d402f0 MP |
1425 | * |
1426 | * If there was someone else holding the buffer, we write it to the new | |
1427 | * location but not relink it, because that other user needs to have the buffer | |
1428 | * at the same place. | |
1429 | */ | |
1430 | void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block) | |
1431 | { | |
1432 | struct dm_bufio_client *c = b->c; | |
1433 | struct dm_buffer *new; | |
1434 | ||
1435 | BUG_ON(dm_bufio_in_request()); | |
1436 | ||
1437 | dm_bufio_lock(c); | |
1438 | ||
1439 | retry: | |
1440 | new = __find(c, new_block); | |
1441 | if (new) { | |
1442 | if (new->hold_count) { | |
1443 | __wait_for_free_buffer(c); | |
1444 | goto retry; | |
1445 | } | |
1446 | ||
1447 | /* | |
1448 | * FIXME: Is there any point waiting for a write that's going | |
1449 | * to be overwritten in a bit? | |
1450 | */ | |
1451 | __make_buffer_clean(new); | |
1452 | __unlink_buffer(new); | |
1453 | __free_buffer_wake(new); | |
1454 | } | |
1455 | ||
1456 | BUG_ON(!b->hold_count); | |
1457 | BUG_ON(test_bit(B_READING, &b->state)); | |
1458 | ||
2480945c | 1459 | __write_dirty_buffer(b, NULL); |
95d402f0 | 1460 | if (b->hold_count == 1) { |
74316201 N |
1461 | wait_on_bit_io(&b->state, B_WRITING, |
1462 | TASK_UNINTERRUPTIBLE); | |
95d402f0 | 1463 | set_bit(B_DIRTY, &b->state); |
1e3b21c6 MP |
1464 | b->dirty_start = 0; |
1465 | b->dirty_end = c->block_size; | |
95d402f0 MP |
1466 | __unlink_buffer(b); |
1467 | __link_buffer(b, new_block, LIST_DIRTY); | |
1468 | } else { | |
1469 | sector_t old_block; | |
0ef0b471 | 1470 | |
74316201 N |
1471 | wait_on_bit_lock_io(&b->state, B_WRITING, |
1472 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1473 | /* |
1474 | * Relink buffer to "new_block" so that write_callback | |
1475 | * sees "new_block" as a block number. | |
1476 | * After the write, link the buffer back to old_block. | |
1477 | * All this must be done in bufio lock, so that block number | |
1478 | * change isn't visible to other threads. | |
1479 | */ | |
1480 | old_block = b->block; | |
1481 | __unlink_buffer(b); | |
1482 | __link_buffer(b, new_block, b->list_mode); | |
905be0a1 | 1483 | submit_io(b, REQ_OP_WRITE, write_endio); |
74316201 N |
1484 | wait_on_bit_io(&b->state, B_WRITING, |
1485 | TASK_UNINTERRUPTIBLE); | |
95d402f0 MP |
1486 | __unlink_buffer(b); |
1487 | __link_buffer(b, old_block, b->list_mode); | |
1488 | } | |
1489 | ||
1490 | dm_bufio_unlock(c); | |
1491 | dm_bufio_release(b); | |
1492 | } | |
1493 | EXPORT_SYMBOL_GPL(dm_bufio_release_move); | |
1494 | ||
33a18062 MP |
1495 | static void forget_buffer_locked(struct dm_buffer *b) |
1496 | { | |
141b3523 | 1497 | if (likely(!b->hold_count) && likely(!smp_load_acquire(&b->state))) { |
33a18062 MP |
1498 | __unlink_buffer(b); |
1499 | __free_buffer_wake(b); | |
1500 | } | |
1501 | } | |
1502 | ||
55494bf2 MP |
1503 | /* |
1504 | * Free the given buffer. | |
1505 | * | |
1506 | * This is just a hint, if the buffer is in use or dirty, this function | |
1507 | * does nothing. | |
1508 | */ | |
1509 | void dm_bufio_forget(struct dm_bufio_client *c, sector_t block) | |
1510 | { | |
1511 | struct dm_buffer *b; | |
1512 | ||
1513 | dm_bufio_lock(c); | |
1514 | ||
1515 | b = __find(c, block); | |
33a18062 MP |
1516 | if (b) |
1517 | forget_buffer_locked(b); | |
55494bf2 MP |
1518 | |
1519 | dm_bufio_unlock(c); | |
1520 | } | |
afa53df8 | 1521 | EXPORT_SYMBOL_GPL(dm_bufio_forget); |
55494bf2 | 1522 | |
33a18062 MP |
1523 | void dm_bufio_forget_buffers(struct dm_bufio_client *c, sector_t block, sector_t n_blocks) |
1524 | { | |
1525 | struct dm_buffer *b; | |
1526 | sector_t end_block = block + n_blocks; | |
1527 | ||
1528 | while (block < end_block) { | |
1529 | dm_bufio_lock(c); | |
1530 | ||
1531 | b = __find_next(c, block); | |
1532 | if (b) { | |
1533 | block = b->block + 1; | |
1534 | forget_buffer_locked(b); | |
1535 | } | |
1536 | ||
1537 | dm_bufio_unlock(c); | |
1538 | ||
1539 | if (!b) | |
1540 | break; | |
1541 | } | |
1542 | ||
1543 | } | |
1544 | EXPORT_SYMBOL_GPL(dm_bufio_forget_buffers); | |
1545 | ||
86a3238c | 1546 | void dm_bufio_set_minimum_buffers(struct dm_bufio_client *c, unsigned int n) |
55b082e6 MP |
1547 | { |
1548 | c->minimum_buffers = n; | |
1549 | } | |
afa53df8 | 1550 | EXPORT_SYMBOL_GPL(dm_bufio_set_minimum_buffers); |
55b082e6 | 1551 | |
86a3238c | 1552 | unsigned int dm_bufio_get_block_size(struct dm_bufio_client *c) |
95d402f0 MP |
1553 | { |
1554 | return c->block_size; | |
1555 | } | |
1556 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_size); | |
1557 | ||
1558 | sector_t dm_bufio_get_device_size(struct dm_bufio_client *c) | |
1559 | { | |
6dcbb52c | 1560 | sector_t s = bdev_nr_sectors(c->bdev); |
0ef0b471 | 1561 | |
a14e5ec6 MP |
1562 | if (s >= c->start) |
1563 | s -= c->start; | |
1564 | else | |
1565 | s = 0; | |
f51f2e0a MP |
1566 | if (likely(c->sectors_per_block_bits >= 0)) |
1567 | s >>= c->sectors_per_block_bits; | |
1568 | else | |
1569 | sector_div(s, c->block_size >> SECTOR_SHIFT); | |
1570 | return s; | |
95d402f0 MP |
1571 | } |
1572 | EXPORT_SYMBOL_GPL(dm_bufio_get_device_size); | |
1573 | ||
9b594826 MP |
1574 | struct dm_io_client *dm_bufio_get_dm_io_client(struct dm_bufio_client *c) |
1575 | { | |
1576 | return c->dm_io; | |
1577 | } | |
1578 | EXPORT_SYMBOL_GPL(dm_bufio_get_dm_io_client); | |
1579 | ||
95d402f0 MP |
1580 | sector_t dm_bufio_get_block_number(struct dm_buffer *b) |
1581 | { | |
1582 | return b->block; | |
1583 | } | |
1584 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_number); | |
1585 | ||
1586 | void *dm_bufio_get_block_data(struct dm_buffer *b) | |
1587 | { | |
1588 | return b->data; | |
1589 | } | |
1590 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_data); | |
1591 | ||
1592 | void *dm_bufio_get_aux_data(struct dm_buffer *b) | |
1593 | { | |
1594 | return b + 1; | |
1595 | } | |
1596 | EXPORT_SYMBOL_GPL(dm_bufio_get_aux_data); | |
1597 | ||
1598 | struct dm_bufio_client *dm_bufio_get_client(struct dm_buffer *b) | |
1599 | { | |
1600 | return b->c; | |
1601 | } | |
1602 | EXPORT_SYMBOL_GPL(dm_bufio_get_client); | |
1603 | ||
1604 | static void drop_buffers(struct dm_bufio_client *c) | |
1605 | { | |
1606 | struct dm_buffer *b; | |
1607 | int i; | |
86bad0c7 | 1608 | bool warned = false; |
95d402f0 MP |
1609 | |
1610 | BUG_ON(dm_bufio_in_request()); | |
1611 | ||
1612 | /* | |
1613 | * An optimization so that the buffers are not written one-by-one. | |
1614 | */ | |
1615 | dm_bufio_write_dirty_buffers_async(c); | |
1616 | ||
1617 | dm_bufio_lock(c); | |
1618 | ||
1619 | while ((b = __get_unclaimed_buffer(c))) | |
1620 | __free_buffer_wake(b); | |
1621 | ||
1622 | for (i = 0; i < LIST_SIZE; i++) | |
86bad0c7 MP |
1623 | list_for_each_entry(b, &c->lru[i], lru_list) { |
1624 | WARN_ON(!warned); | |
1625 | warned = true; | |
95d402f0 MP |
1626 | DMERR("leaked buffer %llx, hold count %u, list %d", |
1627 | (unsigned long long)b->block, b->hold_count, i); | |
86bad0c7 | 1628 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING |
741b58f3 TG |
1629 | stack_trace_print(b->stack_entries, b->stack_len, 1); |
1630 | /* mark unclaimed to avoid BUG_ON below */ | |
1631 | b->hold_count = 0; | |
86bad0c7 MP |
1632 | #endif |
1633 | } | |
1634 | ||
1635 | #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING | |
1636 | while ((b = __get_unclaimed_buffer(c))) | |
1637 | __free_buffer_wake(b); | |
1638 | #endif | |
95d402f0 MP |
1639 | |
1640 | for (i = 0; i < LIST_SIZE; i++) | |
1641 | BUG_ON(!list_empty(&c->lru[i])); | |
1642 | ||
1643 | dm_bufio_unlock(c); | |
1644 | } | |
1645 | ||
1646 | /* | |
33096a78 JT |
1647 | * We may not be able to evict this buffer if IO pending or the client |
1648 | * is still using it. Caller is expected to know buffer is too old. | |
1649 | * | |
9d28eb12 MP |
1650 | * And if GFP_NOFS is used, we must not do any I/O because we hold |
1651 | * dm_bufio_clients_lock and we would risk deadlock if the I/O gets | |
1652 | * rerouted to different bufio client. | |
95d402f0 | 1653 | */ |
33096a78 | 1654 | static bool __try_evict_buffer(struct dm_buffer *b, gfp_t gfp) |
95d402f0 | 1655 | { |
e3a7c294 MP |
1656 | if (!(gfp & __GFP_FS) || |
1657 | (static_branch_unlikely(&no_sleep_enabled) && b->c->no_sleep)) { | |
141b3523 | 1658 | if (test_bit_acquire(B_READING, &b->state) || |
95d402f0 MP |
1659 | test_bit(B_WRITING, &b->state) || |
1660 | test_bit(B_DIRTY, &b->state)) | |
33096a78 | 1661 | return false; |
95d402f0 MP |
1662 | } |
1663 | ||
1664 | if (b->hold_count) | |
33096a78 | 1665 | return false; |
95d402f0 MP |
1666 | |
1667 | __make_buffer_clean(b); | |
1668 | __unlink_buffer(b); | |
1669 | __free_buffer_wake(b); | |
1670 | ||
33096a78 | 1671 | return true; |
95d402f0 MP |
1672 | } |
1673 | ||
13840d38 | 1674 | static unsigned long get_retain_buffers(struct dm_bufio_client *c) |
33096a78 | 1675 | { |
f51f2e0a | 1676 | unsigned long retain_bytes = READ_ONCE(dm_bufio_retain_bytes); |
0ef0b471 | 1677 | |
f51f2e0a MP |
1678 | if (likely(c->sectors_per_block_bits >= 0)) |
1679 | retain_bytes >>= c->sectors_per_block_bits + SECTOR_SHIFT; | |
1680 | else | |
1681 | retain_bytes /= c->block_size; | |
0ef0b471 | 1682 | |
f51f2e0a | 1683 | return retain_bytes; |
33096a78 JT |
1684 | } |
1685 | ||
70704c33 | 1686 | static void __scan(struct dm_bufio_client *c) |
95d402f0 MP |
1687 | { |
1688 | int l; | |
1689 | struct dm_buffer *b, *tmp; | |
33096a78 | 1690 | unsigned long freed = 0; |
fbc7c07e SB |
1691 | unsigned long count = c->n_buffers[LIST_CLEAN] + |
1692 | c->n_buffers[LIST_DIRTY]; | |
13840d38 | 1693 | unsigned long retain_target = get_retain_buffers(c); |
95d402f0 MP |
1694 | |
1695 | for (l = 0; l < LIST_SIZE; l++) { | |
7dc19d5a | 1696 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list) { |
70704c33 MP |
1697 | if (count - freed <= retain_target) |
1698 | atomic_long_set(&c->need_shrink, 0); | |
1699 | if (!atomic_long_read(&c->need_shrink)) | |
1700 | return; | |
1701 | if (__try_evict_buffer(b, GFP_KERNEL)) { | |
1702 | atomic_long_dec(&c->need_shrink); | |
33096a78 | 1703 | freed++; |
70704c33 | 1704 | } |
7cd32674 | 1705 | cond_resched(); |
7dc19d5a | 1706 | } |
95d402f0 MP |
1707 | } |
1708 | } | |
1709 | ||
70704c33 MP |
1710 | static void shrink_work(struct work_struct *w) |
1711 | { | |
1712 | struct dm_bufio_client *c = container_of(w, struct dm_bufio_client, shrink_work); | |
1713 | ||
1714 | dm_bufio_lock(c); | |
1715 | __scan(c); | |
1716 | dm_bufio_unlock(c); | |
1717 | } | |
1718 | ||
1719 | static unsigned long dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) | |
95d402f0 | 1720 | { |
7dc19d5a | 1721 | struct dm_bufio_client *c; |
95d402f0 | 1722 | |
7dc19d5a | 1723 | c = container_of(shrink, struct dm_bufio_client, shrinker); |
70704c33 MP |
1724 | atomic_long_add(sc->nr_to_scan, &c->need_shrink); |
1725 | queue_work(dm_bufio_wq, &c->shrink_work); | |
95d402f0 | 1726 | |
70704c33 | 1727 | return sc->nr_to_scan; |
7dc19d5a | 1728 | } |
95d402f0 | 1729 | |
70704c33 | 1730 | static unsigned long dm_bufio_shrink_count(struct shrinker *shrink, struct shrink_control *sc) |
7dc19d5a | 1731 | { |
d12067f4 | 1732 | struct dm_bufio_client *c = container_of(shrink, struct dm_bufio_client, shrinker); |
fbc7c07e SB |
1733 | unsigned long count = READ_ONCE(c->n_buffers[LIST_CLEAN]) + |
1734 | READ_ONCE(c->n_buffers[LIST_DIRTY]); | |
1735 | unsigned long retain_target = get_retain_buffers(c); | |
70704c33 MP |
1736 | unsigned long queued_for_cleanup = atomic_long_read(&c->need_shrink); |
1737 | ||
1738 | if (unlikely(count < retain_target)) | |
1739 | count = 0; | |
1740 | else | |
1741 | count -= retain_target; | |
95d402f0 | 1742 | |
70704c33 MP |
1743 | if (unlikely(count < queued_for_cleanup)) |
1744 | count = 0; | |
1745 | else | |
1746 | count -= queued_for_cleanup; | |
1747 | ||
1748 | return count; | |
95d402f0 MP |
1749 | } |
1750 | ||
1751 | /* | |
1752 | * Create the buffering interface | |
1753 | */ | |
86a3238c HM |
1754 | struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsigned int block_size, |
1755 | unsigned int reserved_buffers, unsigned int aux_size, | |
95d402f0 | 1756 | void (*alloc_callback)(struct dm_buffer *), |
0fcb100d NH |
1757 | void (*write_callback)(struct dm_buffer *), |
1758 | unsigned int flags) | |
95d402f0 MP |
1759 | { |
1760 | int r; | |
1761 | struct dm_bufio_client *c; | |
86a3238c | 1762 | unsigned int i; |
359dbf19 | 1763 | char slab_name[27]; |
95d402f0 | 1764 | |
f51f2e0a MP |
1765 | if (!block_size || block_size & ((1 << SECTOR_SHIFT) - 1)) { |
1766 | DMERR("%s: block size not specified or is not multiple of 512b", __func__); | |
1767 | r = -EINVAL; | |
1768 | goto bad_client; | |
1769 | } | |
95d402f0 | 1770 | |
d8c712ea | 1771 | c = kzalloc(sizeof(*c), GFP_KERNEL); |
95d402f0 MP |
1772 | if (!c) { |
1773 | r = -ENOMEM; | |
1774 | goto bad_client; | |
1775 | } | |
4e420c45 | 1776 | c->buffer_tree = RB_ROOT; |
95d402f0 MP |
1777 | |
1778 | c->bdev = bdev; | |
1779 | c->block_size = block_size; | |
f51f2e0a MP |
1780 | if (is_power_of_2(block_size)) |
1781 | c->sectors_per_block_bits = __ffs(block_size) - SECTOR_SHIFT; | |
1782 | else | |
1783 | c->sectors_per_block_bits = -1; | |
95d402f0 | 1784 | |
95d402f0 MP |
1785 | c->alloc_callback = alloc_callback; |
1786 | c->write_callback = write_callback; | |
1787 | ||
3c1c875d | 1788 | if (flags & DM_BUFIO_CLIENT_NO_SLEEP) { |
b32d4582 | 1789 | c->no_sleep = true; |
3c1c875d MS |
1790 | static_branch_inc(&no_sleep_enabled); |
1791 | } | |
b32d4582 | 1792 | |
95d402f0 MP |
1793 | for (i = 0; i < LIST_SIZE; i++) { |
1794 | INIT_LIST_HEAD(&c->lru[i]); | |
1795 | c->n_buffers[i] = 0; | |
1796 | } | |
1797 | ||
95d402f0 | 1798 | mutex_init(&c->lock); |
b32d4582 | 1799 | spin_lock_init(&c->spinlock); |
95d402f0 MP |
1800 | INIT_LIST_HEAD(&c->reserved_buffers); |
1801 | c->need_reserved_buffers = reserved_buffers; | |
1802 | ||
afa53df8 | 1803 | dm_bufio_set_minimum_buffers(c, DM_BUFIO_MIN_BUFFERS); |
55b082e6 | 1804 | |
95d402f0 MP |
1805 | init_waitqueue_head(&c->free_buffer_wait); |
1806 | c->async_write_error = 0; | |
1807 | ||
1808 | c->dm_io = dm_io_client_create(); | |
1809 | if (IS_ERR(c->dm_io)) { | |
1810 | r = PTR_ERR(c->dm_io); | |
1811 | goto bad_dm_io; | |
1812 | } | |
1813 | ||
f51f2e0a MP |
1814 | if (block_size <= KMALLOC_MAX_SIZE && |
1815 | (block_size < PAGE_SIZE || !is_power_of_2(block_size))) { | |
86a3238c | 1816 | unsigned int align = min(1U << __ffs(block_size), (unsigned int)PAGE_SIZE); |
0ef0b471 | 1817 | |
f7879b4c MP |
1818 | snprintf(slab_name, sizeof slab_name, "dm_bufio_cache-%u", block_size); |
1819 | c->slab_cache = kmem_cache_create(slab_name, block_size, align, | |
6b5e718c | 1820 | SLAB_RECLAIM_ACCOUNT, NULL); |
21bb1327 MP |
1821 | if (!c->slab_cache) { |
1822 | r = -ENOMEM; | |
1823 | goto bad; | |
95d402f0 MP |
1824 | } |
1825 | } | |
359dbf19 MP |
1826 | if (aux_size) |
1827 | snprintf(slab_name, sizeof slab_name, "dm_bufio_buffer-%u", aux_size); | |
1828 | else | |
1829 | snprintf(slab_name, sizeof slab_name, "dm_bufio_buffer"); | |
1830 | c->slab_buffer = kmem_cache_create(slab_name, sizeof(struct dm_buffer) + aux_size, | |
1831 | 0, SLAB_RECLAIM_ACCOUNT, NULL); | |
1832 | if (!c->slab_buffer) { | |
1833 | r = -ENOMEM; | |
1834 | goto bad; | |
1835 | } | |
95d402f0 MP |
1836 | |
1837 | while (c->need_reserved_buffers) { | |
1838 | struct dm_buffer *b = alloc_buffer(c, GFP_KERNEL); | |
1839 | ||
1840 | if (!b) { | |
1841 | r = -ENOMEM; | |
0e696d38 | 1842 | goto bad; |
95d402f0 MP |
1843 | } |
1844 | __free_buffer_wake(b); | |
1845 | } | |
1846 | ||
70704c33 MP |
1847 | INIT_WORK(&c->shrink_work, shrink_work); |
1848 | atomic_long_set(&c->need_shrink, 0); | |
1849 | ||
46898e9a AK |
1850 | c->shrinker.count_objects = dm_bufio_shrink_count; |
1851 | c->shrinker.scan_objects = dm_bufio_shrink_scan; | |
1852 | c->shrinker.seeks = 1; | |
1853 | c->shrinker.batch = 0; | |
c87791bc | 1854 | r = register_shrinker(&c->shrinker, "dm-bufio:(%u:%u)", |
e33c267a | 1855 | MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev)); |
46898e9a | 1856 | if (r) |
0e696d38 | 1857 | goto bad; |
46898e9a | 1858 | |
95d402f0 MP |
1859 | mutex_lock(&dm_bufio_clients_lock); |
1860 | dm_bufio_client_count++; | |
1861 | list_add(&c->client_list, &dm_bufio_all_clients); | |
1862 | __cache_size_refresh(); | |
1863 | mutex_unlock(&dm_bufio_clients_lock); | |
1864 | ||
95d402f0 MP |
1865 | return c; |
1866 | ||
0e696d38 | 1867 | bad: |
95d402f0 MP |
1868 | while (!list_empty(&c->reserved_buffers)) { |
1869 | struct dm_buffer *b = list_entry(c->reserved_buffers.next, | |
1870 | struct dm_buffer, lru_list); | |
1871 | list_del(&b->lru_list); | |
1872 | free_buffer(b); | |
1873 | } | |
21bb1327 | 1874 | kmem_cache_destroy(c->slab_cache); |
359dbf19 | 1875 | kmem_cache_destroy(c->slab_buffer); |
95d402f0 MP |
1876 | dm_io_client_destroy(c->dm_io); |
1877 | bad_dm_io: | |
bde14184 | 1878 | mutex_destroy(&c->lock); |
0dfc1f4c ZC |
1879 | if (c->no_sleep) |
1880 | static_branch_dec(&no_sleep_enabled); | |
95d402f0 MP |
1881 | kfree(c); |
1882 | bad_client: | |
1883 | return ERR_PTR(r); | |
1884 | } | |
1885 | EXPORT_SYMBOL_GPL(dm_bufio_client_create); | |
1886 | ||
1887 | /* | |
1888 | * Free the buffering interface. | |
1889 | * It is required that there are no references on any buffers. | |
1890 | */ | |
1891 | void dm_bufio_client_destroy(struct dm_bufio_client *c) | |
1892 | { | |
86a3238c | 1893 | unsigned int i; |
95d402f0 MP |
1894 | |
1895 | drop_buffers(c); | |
1896 | ||
1897 | unregister_shrinker(&c->shrinker); | |
70704c33 | 1898 | flush_work(&c->shrink_work); |
95d402f0 MP |
1899 | |
1900 | mutex_lock(&dm_bufio_clients_lock); | |
1901 | ||
1902 | list_del(&c->client_list); | |
1903 | dm_bufio_client_count--; | |
1904 | __cache_size_refresh(); | |
1905 | ||
1906 | mutex_unlock(&dm_bufio_clients_lock); | |
1907 | ||
4e420c45 | 1908 | BUG_ON(!RB_EMPTY_ROOT(&c->buffer_tree)); |
95d402f0 MP |
1909 | BUG_ON(c->need_reserved_buffers); |
1910 | ||
1911 | while (!list_empty(&c->reserved_buffers)) { | |
1912 | struct dm_buffer *b = list_entry(c->reserved_buffers.next, | |
1913 | struct dm_buffer, lru_list); | |
1914 | list_del(&b->lru_list); | |
1915 | free_buffer(b); | |
1916 | } | |
1917 | ||
1918 | for (i = 0; i < LIST_SIZE; i++) | |
1919 | if (c->n_buffers[i]) | |
1920 | DMERR("leaked buffer count %d: %ld", i, c->n_buffers[i]); | |
1921 | ||
1922 | for (i = 0; i < LIST_SIZE; i++) | |
1923 | BUG_ON(c->n_buffers[i]); | |
1924 | ||
21bb1327 | 1925 | kmem_cache_destroy(c->slab_cache); |
359dbf19 | 1926 | kmem_cache_destroy(c->slab_buffer); |
95d402f0 | 1927 | dm_io_client_destroy(c->dm_io); |
bde14184 | 1928 | mutex_destroy(&c->lock); |
3c1c875d MS |
1929 | if (c->no_sleep) |
1930 | static_branch_dec(&no_sleep_enabled); | |
95d402f0 MP |
1931 | kfree(c); |
1932 | } | |
1933 | EXPORT_SYMBOL_GPL(dm_bufio_client_destroy); | |
1934 | ||
400a0bef MP |
1935 | void dm_bufio_set_sector_offset(struct dm_bufio_client *c, sector_t start) |
1936 | { | |
1937 | c->start = start; | |
1938 | } | |
1939 | EXPORT_SYMBOL_GPL(dm_bufio_set_sector_offset); | |
1940 | ||
86a3238c | 1941 | static unsigned int get_max_age_hz(void) |
95d402f0 | 1942 | { |
86a3238c | 1943 | unsigned int max_age = READ_ONCE(dm_bufio_max_age); |
95d402f0 | 1944 | |
33096a78 JT |
1945 | if (max_age > UINT_MAX / HZ) |
1946 | max_age = UINT_MAX / HZ; | |
95d402f0 | 1947 | |
33096a78 JT |
1948 | return max_age * HZ; |
1949 | } | |
95d402f0 | 1950 | |
33096a78 JT |
1951 | static bool older_than(struct dm_buffer *b, unsigned long age_hz) |
1952 | { | |
f495339c | 1953 | return time_after_eq(jiffies, b->last_accessed + age_hz); |
33096a78 JT |
1954 | } |
1955 | ||
1956 | static void __evict_old_buffers(struct dm_bufio_client *c, unsigned long age_hz) | |
1957 | { | |
1958 | struct dm_buffer *b, *tmp; | |
13840d38 MP |
1959 | unsigned long retain_target = get_retain_buffers(c); |
1960 | unsigned long count; | |
390020ad | 1961 | LIST_HEAD(write_list); |
33096a78 JT |
1962 | |
1963 | dm_bufio_lock(c); | |
1964 | ||
390020ad MP |
1965 | __check_watermark(c, &write_list); |
1966 | if (unlikely(!list_empty(&write_list))) { | |
1967 | dm_bufio_unlock(c); | |
1968 | __flush_write_list(&write_list); | |
1969 | dm_bufio_lock(c); | |
1970 | } | |
1971 | ||
33096a78 JT |
1972 | count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY]; |
1973 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_CLEAN], lru_list) { | |
1974 | if (count <= retain_target) | |
1975 | break; | |
1976 | ||
1977 | if (!older_than(b, age_hz)) | |
1978 | break; | |
1979 | ||
1980 | if (__try_evict_buffer(b, 0)) | |
1981 | count--; | |
95d402f0 | 1982 | |
7cd32674 | 1983 | cond_resched(); |
95d402f0 | 1984 | } |
33096a78 JT |
1985 | |
1986 | dm_bufio_unlock(c); | |
1987 | } | |
1988 | ||
6e913b28 MP |
1989 | static void do_global_cleanup(struct work_struct *w) |
1990 | { | |
1991 | struct dm_bufio_client *locked_client = NULL; | |
1992 | struct dm_bufio_client *current_client; | |
1993 | struct dm_buffer *b; | |
86a3238c | 1994 | unsigned int spinlock_hold_count; |
6e913b28 MP |
1995 | unsigned long threshold = dm_bufio_cache_size - |
1996 | dm_bufio_cache_size / DM_BUFIO_LOW_WATERMARK_RATIO; | |
1997 | unsigned long loops = global_num * 2; | |
1998 | ||
1999 | mutex_lock(&dm_bufio_clients_lock); | |
2000 | ||
2001 | while (1) { | |
2002 | cond_resched(); | |
2003 | ||
2004 | spin_lock(&global_spinlock); | |
2005 | if (unlikely(dm_bufio_current_allocated <= threshold)) | |
2006 | break; | |
2007 | ||
2008 | spinlock_hold_count = 0; | |
2009 | get_next: | |
2010 | if (!loops--) | |
2011 | break; | |
2012 | if (unlikely(list_empty(&global_queue))) | |
2013 | break; | |
2014 | b = list_entry(global_queue.prev, struct dm_buffer, global_list); | |
2015 | ||
2016 | if (b->accessed) { | |
2017 | b->accessed = 0; | |
2018 | list_move(&b->global_list, &global_queue); | |
2019 | if (likely(++spinlock_hold_count < 16)) | |
2020 | goto get_next; | |
2021 | spin_unlock(&global_spinlock); | |
2022 | continue; | |
2023 | } | |
2024 | ||
2025 | current_client = b->c; | |
2026 | if (unlikely(current_client != locked_client)) { | |
2027 | if (locked_client) | |
2028 | dm_bufio_unlock(locked_client); | |
2029 | ||
2030 | if (!dm_bufio_trylock(current_client)) { | |
2031 | spin_unlock(&global_spinlock); | |
2032 | dm_bufio_lock(current_client); | |
2033 | locked_client = current_client; | |
2034 | continue; | |
2035 | } | |
2036 | ||
2037 | locked_client = current_client; | |
2038 | } | |
2039 | ||
2040 | spin_unlock(&global_spinlock); | |
2041 | ||
2042 | if (unlikely(!__try_evict_buffer(b, GFP_KERNEL))) { | |
2043 | spin_lock(&global_spinlock); | |
2044 | list_move(&b->global_list, &global_queue); | |
2045 | spin_unlock(&global_spinlock); | |
2046 | } | |
2047 | } | |
2048 | ||
2049 | spin_unlock(&global_spinlock); | |
2050 | ||
2051 | if (locked_client) | |
2052 | dm_bufio_unlock(locked_client); | |
2053 | ||
2054 | mutex_unlock(&dm_bufio_clients_lock); | |
2055 | } | |
2056 | ||
33096a78 JT |
2057 | static void cleanup_old_buffers(void) |
2058 | { | |
2059 | unsigned long max_age_hz = get_max_age_hz(); | |
2060 | struct dm_bufio_client *c; | |
2061 | ||
2062 | mutex_lock(&dm_bufio_clients_lock); | |
2063 | ||
390020ad MP |
2064 | __cache_size_refresh(); |
2065 | ||
33096a78 JT |
2066 | list_for_each_entry(c, &dm_bufio_all_clients, client_list) |
2067 | __evict_old_buffers(c, max_age_hz); | |
2068 | ||
95d402f0 MP |
2069 | mutex_unlock(&dm_bufio_clients_lock); |
2070 | } | |
2071 | ||
95d402f0 MP |
2072 | static void work_fn(struct work_struct *w) |
2073 | { | |
2074 | cleanup_old_buffers(); | |
2075 | ||
6e913b28 | 2076 | queue_delayed_work(dm_bufio_wq, &dm_bufio_cleanup_old_work, |
95d402f0 MP |
2077 | DM_BUFIO_WORK_TIMER_SECS * HZ); |
2078 | } | |
2079 | ||
a4a82ce3 HM |
2080 | /* |
2081 | *-------------------------------------------------------------- | |
95d402f0 | 2082 | * Module setup |
a4a82ce3 HM |
2083 | *-------------------------------------------------------------- |
2084 | */ | |
95d402f0 MP |
2085 | |
2086 | /* | |
2087 | * This is called only once for the whole dm_bufio module. | |
2088 | * It initializes memory limit. | |
2089 | */ | |
2090 | static int __init dm_bufio_init(void) | |
2091 | { | |
2092 | __u64 mem; | |
2093 | ||
4cb57ab4 MP |
2094 | dm_bufio_allocated_kmem_cache = 0; |
2095 | dm_bufio_allocated_get_free_pages = 0; | |
2096 | dm_bufio_allocated_vmalloc = 0; | |
2097 | dm_bufio_current_allocated = 0; | |
2098 | ||
ca79b0c2 | 2099 | mem = (__u64)mult_frac(totalram_pages() - totalhigh_pages(), |
74d4108d | 2100 | DM_BUFIO_MEMORY_PERCENT, 100) << PAGE_SHIFT; |
95d402f0 MP |
2101 | |
2102 | if (mem > ULONG_MAX) | |
2103 | mem = ULONG_MAX; | |
2104 | ||
2105 | #ifdef CONFIG_MMU | |
74d4108d EB |
2106 | if (mem > mult_frac(VMALLOC_TOTAL, DM_BUFIO_VMALLOC_PERCENT, 100)) |
2107 | mem = mult_frac(VMALLOC_TOTAL, DM_BUFIO_VMALLOC_PERCENT, 100); | |
95d402f0 MP |
2108 | #endif |
2109 | ||
2110 | dm_bufio_default_cache_size = mem; | |
2111 | ||
2112 | mutex_lock(&dm_bufio_clients_lock); | |
2113 | __cache_size_refresh(); | |
2114 | mutex_unlock(&dm_bufio_clients_lock); | |
2115 | ||
edd1ea2a | 2116 | dm_bufio_wq = alloc_workqueue("dm_bufio_cache", WQ_MEM_RECLAIM, 0); |
95d402f0 MP |
2117 | if (!dm_bufio_wq) |
2118 | return -ENOMEM; | |
2119 | ||
6e913b28 MP |
2120 | INIT_DELAYED_WORK(&dm_bufio_cleanup_old_work, work_fn); |
2121 | INIT_WORK(&dm_bufio_replacement_work, do_global_cleanup); | |
2122 | queue_delayed_work(dm_bufio_wq, &dm_bufio_cleanup_old_work, | |
95d402f0 MP |
2123 | DM_BUFIO_WORK_TIMER_SECS * HZ); |
2124 | ||
2125 | return 0; | |
2126 | } | |
2127 | ||
2128 | /* | |
2129 | * This is called once when unloading the dm_bufio module. | |
2130 | */ | |
2131 | static void __exit dm_bufio_exit(void) | |
2132 | { | |
2133 | int bug = 0; | |
95d402f0 | 2134 | |
6e913b28 | 2135 | cancel_delayed_work_sync(&dm_bufio_cleanup_old_work); |
95d402f0 MP |
2136 | destroy_workqueue(dm_bufio_wq); |
2137 | ||
95d402f0 MP |
2138 | if (dm_bufio_client_count) { |
2139 | DMCRIT("%s: dm_bufio_client_count leaked: %d", | |
2140 | __func__, dm_bufio_client_count); | |
2141 | bug = 1; | |
2142 | } | |
2143 | ||
2144 | if (dm_bufio_current_allocated) { | |
2145 | DMCRIT("%s: dm_bufio_current_allocated leaked: %lu", | |
2146 | __func__, dm_bufio_current_allocated); | |
2147 | bug = 1; | |
2148 | } | |
2149 | ||
2150 | if (dm_bufio_allocated_get_free_pages) { | |
2151 | DMCRIT("%s: dm_bufio_allocated_get_free_pages leaked: %lu", | |
2152 | __func__, dm_bufio_allocated_get_free_pages); | |
2153 | bug = 1; | |
2154 | } | |
2155 | ||
2156 | if (dm_bufio_allocated_vmalloc) { | |
2157 | DMCRIT("%s: dm_bufio_vmalloc leaked: %lu", | |
2158 | __func__, dm_bufio_allocated_vmalloc); | |
2159 | bug = 1; | |
2160 | } | |
2161 | ||
86a49e2d | 2162 | BUG_ON(bug); |
95d402f0 MP |
2163 | } |
2164 | ||
2165 | module_init(dm_bufio_init) | |
2166 | module_exit(dm_bufio_exit) | |
2167 | ||
2168 | module_param_named(max_cache_size_bytes, dm_bufio_cache_size, ulong, S_IRUGO | S_IWUSR); | |
2169 | MODULE_PARM_DESC(max_cache_size_bytes, "Size of metadata cache"); | |
2170 | ||
2171 | module_param_named(max_age_seconds, dm_bufio_max_age, uint, S_IRUGO | S_IWUSR); | |
2172 | MODULE_PARM_DESC(max_age_seconds, "Max age of a buffer in seconds"); | |
33096a78 | 2173 | |
13840d38 | 2174 | module_param_named(retain_bytes, dm_bufio_retain_bytes, ulong, S_IRUGO | S_IWUSR); |
33096a78 | 2175 | MODULE_PARM_DESC(retain_bytes, "Try to keep at least this many bytes cached in memory"); |
95d402f0 MP |
2176 | |
2177 | module_param_named(peak_allocated_bytes, dm_bufio_peak_allocated, ulong, S_IRUGO | S_IWUSR); | |
2178 | MODULE_PARM_DESC(peak_allocated_bytes, "Tracks the maximum allocated memory"); | |
2179 | ||
2180 | module_param_named(allocated_kmem_cache_bytes, dm_bufio_allocated_kmem_cache, ulong, S_IRUGO); | |
2181 | MODULE_PARM_DESC(allocated_kmem_cache_bytes, "Memory allocated with kmem_cache_alloc"); | |
2182 | ||
2183 | module_param_named(allocated_get_free_pages_bytes, dm_bufio_allocated_get_free_pages, ulong, S_IRUGO); | |
2184 | MODULE_PARM_DESC(allocated_get_free_pages_bytes, "Memory allocated with get_free_pages"); | |
2185 | ||
2186 | module_param_named(allocated_vmalloc_bytes, dm_bufio_allocated_vmalloc, ulong, S_IRUGO); | |
2187 | MODULE_PARM_DESC(allocated_vmalloc_bytes, "Memory allocated with vmalloc"); | |
2188 | ||
2189 | module_param_named(current_allocated_bytes, dm_bufio_current_allocated, ulong, S_IRUGO); | |
2190 | MODULE_PARM_DESC(current_allocated_bytes, "Memory currently used by the cache"); | |
2191 | ||
2192 | MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>"); | |
2193 | MODULE_DESCRIPTION(DM_NAME " buffered I/O library"); | |
2194 | MODULE_LICENSE("GPL"); |