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