Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2009-2011 Red Hat, Inc. |
| 3 | * |
| 4 | * Author: Mikulas Patocka <mpatocka@redhat.com> |
| 5 | * |
| 6 | * This file is released under the GPL. |
| 7 | */ |
| 8 | |
| 9 | #include "dm-bufio.h" |
| 10 | |
| 11 | #include <linux/device-mapper.h> |
| 12 | #include <linux/dm-io.h> |
| 13 | #include <linux/slab.h> |
| 14 | #include <linux/vmalloc.h> |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 15 | #include <linux/shrinker.h> |
Stephen Rothwell | 6f66263 | 2011-11-01 18:30:49 +1100 | [diff] [blame] | 16 | #include <linux/module.h> |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 17 | |
| 18 | #define DM_MSG_PREFIX "bufio" |
| 19 | |
| 20 | /* |
| 21 | * Memory management policy: |
| 22 | * Limit the number of buffers to DM_BUFIO_MEMORY_PERCENT of main memory |
| 23 | * or DM_BUFIO_VMALLOC_PERCENT of vmalloc memory (whichever is lower). |
| 24 | * Always allocate at least DM_BUFIO_MIN_BUFFERS buffers. |
| 25 | * Start background writeback when there are DM_BUFIO_WRITEBACK_PERCENT |
| 26 | * dirty buffers. |
| 27 | */ |
| 28 | #define DM_BUFIO_MIN_BUFFERS 8 |
| 29 | |
| 30 | #define DM_BUFIO_MEMORY_PERCENT 2 |
| 31 | #define DM_BUFIO_VMALLOC_PERCENT 25 |
| 32 | #define DM_BUFIO_WRITEBACK_PERCENT 75 |
| 33 | |
| 34 | /* |
| 35 | * Check buffer ages in this interval (seconds) |
| 36 | */ |
| 37 | #define DM_BUFIO_WORK_TIMER_SECS 10 |
| 38 | |
| 39 | /* |
| 40 | * Free buffers when they are older than this (seconds) |
| 41 | */ |
| 42 | #define DM_BUFIO_DEFAULT_AGE_SECS 60 |
| 43 | |
| 44 | /* |
| 45 | * The number of bvec entries that are embedded directly in the buffer. |
| 46 | * If the chunk size is larger, dm-io is used to do the io. |
| 47 | */ |
| 48 | #define DM_BUFIO_INLINE_VECS 16 |
| 49 | |
| 50 | /* |
| 51 | * Buffer hash |
| 52 | */ |
| 53 | #define DM_BUFIO_HASH_BITS 20 |
| 54 | #define DM_BUFIO_HASH(block) \ |
| 55 | ((((block) >> DM_BUFIO_HASH_BITS) ^ (block)) & \ |
| 56 | ((1 << DM_BUFIO_HASH_BITS) - 1)) |
| 57 | |
| 58 | /* |
| 59 | * Don't try to use kmem_cache_alloc for blocks larger than this. |
| 60 | * For explanation, see alloc_buffer_data below. |
| 61 | */ |
| 62 | #define DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT (PAGE_SIZE >> 1) |
| 63 | #define DM_BUFIO_BLOCK_SIZE_GFP_LIMIT (PAGE_SIZE << (MAX_ORDER - 1)) |
| 64 | |
| 65 | /* |
| 66 | * dm_buffer->list_mode |
| 67 | */ |
| 68 | #define LIST_CLEAN 0 |
| 69 | #define LIST_DIRTY 1 |
| 70 | #define LIST_SIZE 2 |
| 71 | |
| 72 | /* |
| 73 | * Linking of buffers: |
| 74 | * All buffers are linked to cache_hash with their hash_list field. |
| 75 | * |
| 76 | * Clean buffers that are not being written (B_WRITING not set) |
| 77 | * are linked to lru[LIST_CLEAN] with their lru_list field. |
| 78 | * |
| 79 | * Dirty and clean buffers that are being written are linked to |
| 80 | * lru[LIST_DIRTY] with their lru_list field. When the write |
| 81 | * finishes, the buffer cannot be relinked immediately (because we |
| 82 | * are in an interrupt context and relinking requires process |
| 83 | * context), so some clean-not-writing buffers can be held on |
| 84 | * dirty_lru too. They are later added to lru in the process |
| 85 | * context. |
| 86 | */ |
| 87 | struct dm_bufio_client { |
| 88 | struct mutex lock; |
| 89 | |
| 90 | struct list_head lru[LIST_SIZE]; |
| 91 | unsigned long n_buffers[LIST_SIZE]; |
| 92 | |
| 93 | struct block_device *bdev; |
| 94 | unsigned block_size; |
| 95 | unsigned char sectors_per_block_bits; |
| 96 | unsigned char pages_per_block_bits; |
| 97 | unsigned char blocks_per_page_bits; |
| 98 | unsigned aux_size; |
| 99 | void (*alloc_callback)(struct dm_buffer *); |
| 100 | void (*write_callback)(struct dm_buffer *); |
| 101 | |
| 102 | struct dm_io_client *dm_io; |
| 103 | |
| 104 | struct list_head reserved_buffers; |
| 105 | unsigned need_reserved_buffers; |
| 106 | |
| 107 | struct hlist_head *cache_hash; |
| 108 | wait_queue_head_t free_buffer_wait; |
| 109 | |
| 110 | int async_write_error; |
| 111 | |
| 112 | struct list_head client_list; |
| 113 | struct shrinker shrinker; |
| 114 | }; |
| 115 | |
| 116 | /* |
| 117 | * Buffer state bits. |
| 118 | */ |
| 119 | #define B_READING 0 |
| 120 | #define B_WRITING 1 |
| 121 | #define B_DIRTY 2 |
| 122 | |
| 123 | /* |
| 124 | * Describes how the block was allocated: |
| 125 | * kmem_cache_alloc(), __get_free_pages() or vmalloc(). |
| 126 | * See the comment at alloc_buffer_data. |
| 127 | */ |
| 128 | enum data_mode { |
| 129 | DATA_MODE_SLAB = 0, |
| 130 | DATA_MODE_GET_FREE_PAGES = 1, |
| 131 | DATA_MODE_VMALLOC = 2, |
| 132 | DATA_MODE_LIMIT = 3 |
| 133 | }; |
| 134 | |
| 135 | struct dm_buffer { |
| 136 | struct hlist_node hash_list; |
| 137 | struct list_head lru_list; |
| 138 | sector_t block; |
| 139 | void *data; |
| 140 | enum data_mode data_mode; |
| 141 | unsigned char list_mode; /* LIST_* */ |
| 142 | unsigned hold_count; |
| 143 | int read_error; |
| 144 | int write_error; |
| 145 | unsigned long state; |
| 146 | unsigned long last_accessed; |
| 147 | struct dm_bufio_client *c; |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 148 | struct list_head write_list; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 149 | struct bio bio; |
| 150 | struct bio_vec bio_vec[DM_BUFIO_INLINE_VECS]; |
| 151 | }; |
| 152 | |
| 153 | /*----------------------------------------------------------------*/ |
| 154 | |
| 155 | static struct kmem_cache *dm_bufio_caches[PAGE_SHIFT - SECTOR_SHIFT]; |
| 156 | static char *dm_bufio_cache_names[PAGE_SHIFT - SECTOR_SHIFT]; |
| 157 | |
| 158 | static inline int dm_bufio_cache_index(struct dm_bufio_client *c) |
| 159 | { |
| 160 | unsigned ret = c->blocks_per_page_bits - 1; |
| 161 | |
| 162 | BUG_ON(ret >= ARRAY_SIZE(dm_bufio_caches)); |
| 163 | |
| 164 | return ret; |
| 165 | } |
| 166 | |
| 167 | #define DM_BUFIO_CACHE(c) (dm_bufio_caches[dm_bufio_cache_index(c)]) |
| 168 | #define DM_BUFIO_CACHE_NAME(c) (dm_bufio_cache_names[dm_bufio_cache_index(c)]) |
| 169 | |
| 170 | #define dm_bufio_in_request() (!!current->bio_list) |
| 171 | |
| 172 | static void dm_bufio_lock(struct dm_bufio_client *c) |
| 173 | { |
| 174 | mutex_lock_nested(&c->lock, dm_bufio_in_request()); |
| 175 | } |
| 176 | |
| 177 | static int dm_bufio_trylock(struct dm_bufio_client *c) |
| 178 | { |
| 179 | return mutex_trylock(&c->lock); |
| 180 | } |
| 181 | |
| 182 | static void dm_bufio_unlock(struct dm_bufio_client *c) |
| 183 | { |
| 184 | mutex_unlock(&c->lock); |
| 185 | } |
| 186 | |
| 187 | /* |
| 188 | * FIXME Move to sched.h? |
| 189 | */ |
| 190 | #ifdef CONFIG_PREEMPT_VOLUNTARY |
| 191 | # define dm_bufio_cond_resched() \ |
| 192 | do { \ |
| 193 | if (unlikely(need_resched())) \ |
| 194 | _cond_resched(); \ |
| 195 | } while (0) |
| 196 | #else |
| 197 | # define dm_bufio_cond_resched() do { } while (0) |
| 198 | #endif |
| 199 | |
| 200 | /*----------------------------------------------------------------*/ |
| 201 | |
| 202 | /* |
| 203 | * Default cache size: available memory divided by the ratio. |
| 204 | */ |
| 205 | static unsigned long dm_bufio_default_cache_size; |
| 206 | |
| 207 | /* |
| 208 | * Total cache size set by the user. |
| 209 | */ |
| 210 | static unsigned long dm_bufio_cache_size; |
| 211 | |
| 212 | /* |
| 213 | * A copy of dm_bufio_cache_size because dm_bufio_cache_size can change |
| 214 | * at any time. If it disagrees, the user has changed cache size. |
| 215 | */ |
| 216 | static unsigned long dm_bufio_cache_size_latch; |
| 217 | |
| 218 | static DEFINE_SPINLOCK(param_spinlock); |
| 219 | |
| 220 | /* |
| 221 | * Buffers are freed after this timeout |
| 222 | */ |
| 223 | static unsigned dm_bufio_max_age = DM_BUFIO_DEFAULT_AGE_SECS; |
| 224 | |
| 225 | static unsigned long dm_bufio_peak_allocated; |
| 226 | static unsigned long dm_bufio_allocated_kmem_cache; |
| 227 | static unsigned long dm_bufio_allocated_get_free_pages; |
| 228 | static unsigned long dm_bufio_allocated_vmalloc; |
| 229 | static unsigned long dm_bufio_current_allocated; |
| 230 | |
| 231 | /*----------------------------------------------------------------*/ |
| 232 | |
| 233 | /* |
| 234 | * Per-client cache: dm_bufio_cache_size / dm_bufio_client_count |
| 235 | */ |
| 236 | static unsigned long dm_bufio_cache_size_per_client; |
| 237 | |
| 238 | /* |
| 239 | * The current number of clients. |
| 240 | */ |
| 241 | static int dm_bufio_client_count; |
| 242 | |
| 243 | /* |
| 244 | * The list of all clients. |
| 245 | */ |
| 246 | static LIST_HEAD(dm_bufio_all_clients); |
| 247 | |
| 248 | /* |
| 249 | * This mutex protects dm_bufio_cache_size_latch, |
| 250 | * dm_bufio_cache_size_per_client and dm_bufio_client_count |
| 251 | */ |
| 252 | static DEFINE_MUTEX(dm_bufio_clients_lock); |
| 253 | |
| 254 | /*----------------------------------------------------------------*/ |
| 255 | |
| 256 | static void adjust_total_allocated(enum data_mode data_mode, long diff) |
| 257 | { |
| 258 | static unsigned long * const class_ptr[DATA_MODE_LIMIT] = { |
| 259 | &dm_bufio_allocated_kmem_cache, |
| 260 | &dm_bufio_allocated_get_free_pages, |
| 261 | &dm_bufio_allocated_vmalloc, |
| 262 | }; |
| 263 | |
| 264 | spin_lock(¶m_spinlock); |
| 265 | |
| 266 | *class_ptr[data_mode] += diff; |
| 267 | |
| 268 | dm_bufio_current_allocated += diff; |
| 269 | |
| 270 | if (dm_bufio_current_allocated > dm_bufio_peak_allocated) |
| 271 | dm_bufio_peak_allocated = dm_bufio_current_allocated; |
| 272 | |
| 273 | spin_unlock(¶m_spinlock); |
| 274 | } |
| 275 | |
| 276 | /* |
| 277 | * Change the number of clients and recalculate per-client limit. |
| 278 | */ |
| 279 | static void __cache_size_refresh(void) |
| 280 | { |
| 281 | BUG_ON(!mutex_is_locked(&dm_bufio_clients_lock)); |
| 282 | BUG_ON(dm_bufio_client_count < 0); |
| 283 | |
Mikulas Patocka | fe5fe90 | 2012-10-12 16:59:46 +0100 | [diff] [blame] | 284 | dm_bufio_cache_size_latch = ACCESS_ONCE(dm_bufio_cache_size); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 285 | |
| 286 | /* |
| 287 | * Use default if set to 0 and report the actual cache size used. |
| 288 | */ |
| 289 | if (!dm_bufio_cache_size_latch) { |
| 290 | (void)cmpxchg(&dm_bufio_cache_size, 0, |
| 291 | dm_bufio_default_cache_size); |
| 292 | dm_bufio_cache_size_latch = dm_bufio_default_cache_size; |
| 293 | } |
| 294 | |
| 295 | dm_bufio_cache_size_per_client = dm_bufio_cache_size_latch / |
| 296 | (dm_bufio_client_count ? : 1); |
| 297 | } |
| 298 | |
| 299 | /* |
| 300 | * Allocating buffer data. |
| 301 | * |
| 302 | * Small buffers are allocated with kmem_cache, to use space optimally. |
| 303 | * |
| 304 | * For large buffers, we choose between get_free_pages and vmalloc. |
| 305 | * Each has advantages and disadvantages. |
| 306 | * |
| 307 | * __get_free_pages can randomly fail if the memory is fragmented. |
| 308 | * __vmalloc won't randomly fail, but vmalloc space is limited (it may be |
| 309 | * as low as 128M) so using it for caching is not appropriate. |
| 310 | * |
| 311 | * If the allocation may fail we use __get_free_pages. Memory fragmentation |
| 312 | * won't have a fatal effect here, but it just causes flushes of some other |
| 313 | * buffers and more I/O will be performed. Don't use __get_free_pages if it |
| 314 | * always fails (i.e. order >= MAX_ORDER). |
| 315 | * |
| 316 | * If the allocation shouldn't fail we use __vmalloc. This is only for the |
| 317 | * initial reserve allocation, so there's no risk of wasting all vmalloc |
| 318 | * space. |
| 319 | */ |
| 320 | static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask, |
| 321 | enum data_mode *data_mode) |
| 322 | { |
Mikulas Patocka | 502624b | 2013-05-10 14:37:15 +0100 | [diff] [blame] | 323 | unsigned noio_flag; |
| 324 | void *ptr; |
| 325 | |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 326 | if (c->block_size <= DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT) { |
| 327 | *data_mode = DATA_MODE_SLAB; |
| 328 | return kmem_cache_alloc(DM_BUFIO_CACHE(c), gfp_mask); |
| 329 | } |
| 330 | |
| 331 | if (c->block_size <= DM_BUFIO_BLOCK_SIZE_GFP_LIMIT && |
| 332 | gfp_mask & __GFP_NORETRY) { |
| 333 | *data_mode = DATA_MODE_GET_FREE_PAGES; |
| 334 | return (void *)__get_free_pages(gfp_mask, |
| 335 | c->pages_per_block_bits); |
| 336 | } |
| 337 | |
| 338 | *data_mode = DATA_MODE_VMALLOC; |
Mikulas Patocka | 502624b | 2013-05-10 14:37:15 +0100 | [diff] [blame] | 339 | |
| 340 | /* |
| 341 | * __vmalloc allocates the data pages and auxiliary structures with |
| 342 | * gfp_flags that were specified, but pagetables are always allocated |
| 343 | * with GFP_KERNEL, no matter what was specified as gfp_mask. |
| 344 | * |
| 345 | * Consequently, we must set per-process flag PF_MEMALLOC_NOIO so that |
| 346 | * all allocations done by this process (including pagetables) are done |
| 347 | * as if GFP_NOIO was specified. |
| 348 | */ |
| 349 | |
| 350 | if (gfp_mask & __GFP_NORETRY) |
| 351 | noio_flag = memalloc_noio_save(); |
| 352 | |
Mikulas Patocka | 220cd05 | 2013-07-10 23:41:16 +0100 | [diff] [blame] | 353 | ptr = __vmalloc(c->block_size, gfp_mask | __GFP_HIGHMEM, PAGE_KERNEL); |
Mikulas Patocka | 502624b | 2013-05-10 14:37:15 +0100 | [diff] [blame] | 354 | |
| 355 | if (gfp_mask & __GFP_NORETRY) |
| 356 | memalloc_noio_restore(noio_flag); |
| 357 | |
| 358 | return ptr; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 359 | } |
| 360 | |
| 361 | /* |
| 362 | * Free buffer's data. |
| 363 | */ |
| 364 | static void free_buffer_data(struct dm_bufio_client *c, |
| 365 | void *data, enum data_mode data_mode) |
| 366 | { |
| 367 | switch (data_mode) { |
| 368 | case DATA_MODE_SLAB: |
| 369 | kmem_cache_free(DM_BUFIO_CACHE(c), data); |
| 370 | break; |
| 371 | |
| 372 | case DATA_MODE_GET_FREE_PAGES: |
| 373 | free_pages((unsigned long)data, c->pages_per_block_bits); |
| 374 | break; |
| 375 | |
| 376 | case DATA_MODE_VMALLOC: |
| 377 | vfree(data); |
| 378 | break; |
| 379 | |
| 380 | default: |
| 381 | DMCRIT("dm_bufio_free_buffer_data: bad data mode: %d", |
| 382 | data_mode); |
| 383 | BUG(); |
| 384 | } |
| 385 | } |
| 386 | |
| 387 | /* |
| 388 | * Allocate buffer and its data. |
| 389 | */ |
| 390 | static struct dm_buffer *alloc_buffer(struct dm_bufio_client *c, gfp_t gfp_mask) |
| 391 | { |
| 392 | struct dm_buffer *b = kmalloc(sizeof(struct dm_buffer) + c->aux_size, |
| 393 | gfp_mask); |
| 394 | |
| 395 | if (!b) |
| 396 | return NULL; |
| 397 | |
| 398 | b->c = c; |
| 399 | |
| 400 | b->data = alloc_buffer_data(c, gfp_mask, &b->data_mode); |
| 401 | if (!b->data) { |
| 402 | kfree(b); |
| 403 | return NULL; |
| 404 | } |
| 405 | |
| 406 | adjust_total_allocated(b->data_mode, (long)c->block_size); |
| 407 | |
| 408 | return b; |
| 409 | } |
| 410 | |
| 411 | /* |
| 412 | * Free buffer and its data. |
| 413 | */ |
| 414 | static void free_buffer(struct dm_buffer *b) |
| 415 | { |
| 416 | struct dm_bufio_client *c = b->c; |
| 417 | |
| 418 | adjust_total_allocated(b->data_mode, -(long)c->block_size); |
| 419 | |
| 420 | free_buffer_data(c, b->data, b->data_mode); |
| 421 | kfree(b); |
| 422 | } |
| 423 | |
| 424 | /* |
| 425 | * Link buffer to the hash list and clean or dirty queue. |
| 426 | */ |
| 427 | static void __link_buffer(struct dm_buffer *b, sector_t block, int dirty) |
| 428 | { |
| 429 | struct dm_bufio_client *c = b->c; |
| 430 | |
| 431 | c->n_buffers[dirty]++; |
| 432 | b->block = block; |
| 433 | b->list_mode = dirty; |
| 434 | list_add(&b->lru_list, &c->lru[dirty]); |
| 435 | hlist_add_head(&b->hash_list, &c->cache_hash[DM_BUFIO_HASH(block)]); |
| 436 | b->last_accessed = jiffies; |
| 437 | } |
| 438 | |
| 439 | /* |
| 440 | * Unlink buffer from the hash list and dirty or clean queue. |
| 441 | */ |
| 442 | static void __unlink_buffer(struct dm_buffer *b) |
| 443 | { |
| 444 | struct dm_bufio_client *c = b->c; |
| 445 | |
| 446 | BUG_ON(!c->n_buffers[b->list_mode]); |
| 447 | |
| 448 | c->n_buffers[b->list_mode]--; |
| 449 | hlist_del(&b->hash_list); |
| 450 | list_del(&b->lru_list); |
| 451 | } |
| 452 | |
| 453 | /* |
| 454 | * Place the buffer to the head of dirty or clean LRU queue. |
| 455 | */ |
| 456 | static void __relink_lru(struct dm_buffer *b, int dirty) |
| 457 | { |
| 458 | struct dm_bufio_client *c = b->c; |
| 459 | |
| 460 | BUG_ON(!c->n_buffers[b->list_mode]); |
| 461 | |
| 462 | c->n_buffers[b->list_mode]--; |
| 463 | c->n_buffers[dirty]++; |
| 464 | b->list_mode = dirty; |
Wei Yongjun | 54499af | 2012-10-12 16:59:44 +0100 | [diff] [blame] | 465 | list_move(&b->lru_list, &c->lru[dirty]); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 466 | } |
| 467 | |
| 468 | /*---------------------------------------------------------------- |
| 469 | * Submit I/O on the buffer. |
| 470 | * |
| 471 | * Bio interface is faster but it has some problems: |
| 472 | * the vector list is limited (increasing this limit increases |
| 473 | * memory-consumption per buffer, so it is not viable); |
| 474 | * |
| 475 | * the memory must be direct-mapped, not vmalloced; |
| 476 | * |
| 477 | * the I/O driver can reject requests spuriously if it thinks that |
| 478 | * the requests are too big for the device or if they cross a |
| 479 | * controller-defined memory boundary. |
| 480 | * |
| 481 | * If the buffer is small enough (up to DM_BUFIO_INLINE_VECS pages) and |
| 482 | * it is not vmalloced, try using the bio interface. |
| 483 | * |
| 484 | * If the buffer is big, if it is vmalloced or if the underlying device |
| 485 | * rejects the bio because it is too large, use dm-io layer to do the I/O. |
| 486 | * The dm-io layer splits the I/O into multiple requests, avoiding the above |
| 487 | * shortcomings. |
| 488 | *--------------------------------------------------------------*/ |
| 489 | |
| 490 | /* |
| 491 | * dm-io completion routine. It just calls b->bio.bi_end_io, pretending |
| 492 | * that the request was handled directly with bio interface. |
| 493 | */ |
| 494 | static void dmio_complete(unsigned long error, void *context) |
| 495 | { |
| 496 | struct dm_buffer *b = context; |
| 497 | |
| 498 | b->bio.bi_end_io(&b->bio, error ? -EIO : 0); |
| 499 | } |
| 500 | |
| 501 | static void use_dmio(struct dm_buffer *b, int rw, sector_t block, |
| 502 | bio_end_io_t *end_io) |
| 503 | { |
| 504 | int r; |
| 505 | struct dm_io_request io_req = { |
| 506 | .bi_rw = rw, |
| 507 | .notify.fn = dmio_complete, |
| 508 | .notify.context = b, |
| 509 | .client = b->c->dm_io, |
| 510 | }; |
| 511 | struct dm_io_region region = { |
| 512 | .bdev = b->c->bdev, |
| 513 | .sector = block << b->c->sectors_per_block_bits, |
| 514 | .count = b->c->block_size >> SECTOR_SHIFT, |
| 515 | }; |
| 516 | |
| 517 | if (b->data_mode != DATA_MODE_VMALLOC) { |
| 518 | io_req.mem.type = DM_IO_KMEM; |
| 519 | io_req.mem.ptr.addr = b->data; |
| 520 | } else { |
| 521 | io_req.mem.type = DM_IO_VMA; |
| 522 | io_req.mem.ptr.vma = b->data; |
| 523 | } |
| 524 | |
| 525 | b->bio.bi_end_io = end_io; |
| 526 | |
| 527 | r = dm_io(&io_req, 1, ®ion, NULL); |
| 528 | if (r) |
| 529 | end_io(&b->bio, r); |
| 530 | } |
| 531 | |
| 532 | static void use_inline_bio(struct dm_buffer *b, int rw, sector_t block, |
| 533 | bio_end_io_t *end_io) |
| 534 | { |
| 535 | char *ptr; |
| 536 | int len; |
| 537 | |
| 538 | bio_init(&b->bio); |
| 539 | b->bio.bi_io_vec = b->bio_vec; |
| 540 | b->bio.bi_max_vecs = DM_BUFIO_INLINE_VECS; |
| 541 | b->bio.bi_sector = block << b->c->sectors_per_block_bits; |
| 542 | b->bio.bi_bdev = b->c->bdev; |
| 543 | b->bio.bi_end_io = end_io; |
| 544 | |
| 545 | /* |
| 546 | * We assume that if len >= PAGE_SIZE ptr is page-aligned. |
| 547 | * If len < PAGE_SIZE the buffer doesn't cross page boundary. |
| 548 | */ |
| 549 | ptr = b->data; |
| 550 | len = b->c->block_size; |
| 551 | |
| 552 | if (len >= PAGE_SIZE) |
| 553 | BUG_ON((unsigned long)ptr & (PAGE_SIZE - 1)); |
| 554 | else |
| 555 | BUG_ON((unsigned long)ptr & (len - 1)); |
| 556 | |
| 557 | do { |
| 558 | if (!bio_add_page(&b->bio, virt_to_page(ptr), |
| 559 | len < PAGE_SIZE ? len : PAGE_SIZE, |
| 560 | virt_to_phys(ptr) & (PAGE_SIZE - 1))) { |
| 561 | BUG_ON(b->c->block_size <= PAGE_SIZE); |
| 562 | use_dmio(b, rw, block, end_io); |
| 563 | return; |
| 564 | } |
| 565 | |
| 566 | len -= PAGE_SIZE; |
| 567 | ptr += PAGE_SIZE; |
| 568 | } while (len > 0); |
| 569 | |
| 570 | submit_bio(rw, &b->bio); |
| 571 | } |
| 572 | |
| 573 | static void submit_io(struct dm_buffer *b, int rw, sector_t block, |
| 574 | bio_end_io_t *end_io) |
| 575 | { |
| 576 | if (rw == WRITE && b->c->write_callback) |
| 577 | b->c->write_callback(b); |
| 578 | |
| 579 | if (b->c->block_size <= DM_BUFIO_INLINE_VECS * PAGE_SIZE && |
| 580 | b->data_mode != DATA_MODE_VMALLOC) |
| 581 | use_inline_bio(b, rw, block, end_io); |
| 582 | else |
| 583 | use_dmio(b, rw, block, end_io); |
| 584 | } |
| 585 | |
| 586 | /*---------------------------------------------------------------- |
| 587 | * Writing dirty buffers |
| 588 | *--------------------------------------------------------------*/ |
| 589 | |
| 590 | /* |
| 591 | * The endio routine for write. |
| 592 | * |
| 593 | * Set the error, clear B_WRITING bit and wake anyone who was waiting on |
| 594 | * it. |
| 595 | */ |
| 596 | static void write_endio(struct bio *bio, int error) |
| 597 | { |
| 598 | struct dm_buffer *b = container_of(bio, struct dm_buffer, bio); |
| 599 | |
| 600 | b->write_error = error; |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 601 | if (unlikely(error)) { |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 602 | struct dm_bufio_client *c = b->c; |
| 603 | (void)cmpxchg(&c->async_write_error, 0, error); |
| 604 | } |
| 605 | |
| 606 | BUG_ON(!test_bit(B_WRITING, &b->state)); |
| 607 | |
| 608 | smp_mb__before_clear_bit(); |
| 609 | clear_bit(B_WRITING, &b->state); |
| 610 | smp_mb__after_clear_bit(); |
| 611 | |
| 612 | wake_up_bit(&b->state, B_WRITING); |
| 613 | } |
| 614 | |
| 615 | /* |
| 616 | * This function is called when wait_on_bit is actually waiting. |
| 617 | */ |
| 618 | static int do_io_schedule(void *word) |
| 619 | { |
| 620 | io_schedule(); |
| 621 | |
| 622 | return 0; |
| 623 | } |
| 624 | |
| 625 | /* |
| 626 | * Initiate a write on a dirty buffer, but don't wait for it. |
| 627 | * |
| 628 | * - If the buffer is not dirty, exit. |
| 629 | * - If there some previous write going on, wait for it to finish (we can't |
| 630 | * have two writes on the same buffer simultaneously). |
| 631 | * - Submit our write and don't wait on it. We set B_WRITING indicating |
| 632 | * that there is a write in progress. |
| 633 | */ |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 634 | static void __write_dirty_buffer(struct dm_buffer *b, |
| 635 | struct list_head *write_list) |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 636 | { |
| 637 | if (!test_bit(B_DIRTY, &b->state)) |
| 638 | return; |
| 639 | |
| 640 | clear_bit(B_DIRTY, &b->state); |
| 641 | wait_on_bit_lock(&b->state, B_WRITING, |
| 642 | do_io_schedule, TASK_UNINTERRUPTIBLE); |
| 643 | |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 644 | if (!write_list) |
| 645 | submit_io(b, WRITE, b->block, write_endio); |
| 646 | else |
| 647 | list_add_tail(&b->write_list, write_list); |
| 648 | } |
| 649 | |
| 650 | static void __flush_write_list(struct list_head *write_list) |
| 651 | { |
| 652 | struct blk_plug plug; |
| 653 | blk_start_plug(&plug); |
| 654 | while (!list_empty(write_list)) { |
| 655 | struct dm_buffer *b = |
| 656 | list_entry(write_list->next, struct dm_buffer, write_list); |
| 657 | list_del(&b->write_list); |
| 658 | submit_io(b, WRITE, b->block, write_endio); |
| 659 | dm_bufio_cond_resched(); |
| 660 | } |
| 661 | blk_finish_plug(&plug); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 662 | } |
| 663 | |
| 664 | /* |
| 665 | * Wait until any activity on the buffer finishes. Possibly write the |
| 666 | * buffer if it is dirty. When this function finishes, there is no I/O |
| 667 | * running on the buffer and the buffer is not dirty. |
| 668 | */ |
| 669 | static void __make_buffer_clean(struct dm_buffer *b) |
| 670 | { |
| 671 | BUG_ON(b->hold_count); |
| 672 | |
| 673 | if (!b->state) /* fast case */ |
| 674 | return; |
| 675 | |
| 676 | wait_on_bit(&b->state, B_READING, do_io_schedule, TASK_UNINTERRUPTIBLE); |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 677 | __write_dirty_buffer(b, NULL); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 678 | wait_on_bit(&b->state, B_WRITING, do_io_schedule, TASK_UNINTERRUPTIBLE); |
| 679 | } |
| 680 | |
| 681 | /* |
| 682 | * Find some buffer that is not held by anybody, clean it, unlink it and |
| 683 | * return it. |
| 684 | */ |
| 685 | static struct dm_buffer *__get_unclaimed_buffer(struct dm_bufio_client *c) |
| 686 | { |
| 687 | struct dm_buffer *b; |
| 688 | |
| 689 | list_for_each_entry_reverse(b, &c->lru[LIST_CLEAN], lru_list) { |
| 690 | BUG_ON(test_bit(B_WRITING, &b->state)); |
| 691 | BUG_ON(test_bit(B_DIRTY, &b->state)); |
| 692 | |
| 693 | if (!b->hold_count) { |
| 694 | __make_buffer_clean(b); |
| 695 | __unlink_buffer(b); |
| 696 | return b; |
| 697 | } |
| 698 | dm_bufio_cond_resched(); |
| 699 | } |
| 700 | |
| 701 | list_for_each_entry_reverse(b, &c->lru[LIST_DIRTY], lru_list) { |
| 702 | BUG_ON(test_bit(B_READING, &b->state)); |
| 703 | |
| 704 | if (!b->hold_count) { |
| 705 | __make_buffer_clean(b); |
| 706 | __unlink_buffer(b); |
| 707 | return b; |
| 708 | } |
| 709 | dm_bufio_cond_resched(); |
| 710 | } |
| 711 | |
| 712 | return NULL; |
| 713 | } |
| 714 | |
| 715 | /* |
| 716 | * Wait until some other threads free some buffer or release hold count on |
| 717 | * some buffer. |
| 718 | * |
| 719 | * This function is entered with c->lock held, drops it and regains it |
| 720 | * before exiting. |
| 721 | */ |
| 722 | static void __wait_for_free_buffer(struct dm_bufio_client *c) |
| 723 | { |
| 724 | DECLARE_WAITQUEUE(wait, current); |
| 725 | |
| 726 | add_wait_queue(&c->free_buffer_wait, &wait); |
| 727 | set_task_state(current, TASK_UNINTERRUPTIBLE); |
| 728 | dm_bufio_unlock(c); |
| 729 | |
| 730 | io_schedule(); |
| 731 | |
| 732 | set_task_state(current, TASK_RUNNING); |
| 733 | remove_wait_queue(&c->free_buffer_wait, &wait); |
| 734 | |
| 735 | dm_bufio_lock(c); |
| 736 | } |
| 737 | |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 738 | enum new_flag { |
| 739 | NF_FRESH = 0, |
| 740 | NF_READ = 1, |
| 741 | NF_GET = 2, |
| 742 | NF_PREFETCH = 3 |
| 743 | }; |
| 744 | |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 745 | /* |
| 746 | * Allocate a new buffer. If the allocation is not possible, wait until |
| 747 | * some other thread frees a buffer. |
| 748 | * |
| 749 | * May drop the lock and regain it. |
| 750 | */ |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 751 | static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client *c, enum new_flag nf) |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 752 | { |
| 753 | struct dm_buffer *b; |
| 754 | |
| 755 | /* |
| 756 | * dm-bufio is resistant to allocation failures (it just keeps |
| 757 | * one buffer reserved in cases all the allocations fail). |
| 758 | * So set flags to not try too hard: |
| 759 | * GFP_NOIO: don't recurse into the I/O layer |
| 760 | * __GFP_NORETRY: don't retry and rather return failure |
| 761 | * __GFP_NOMEMALLOC: don't use emergency reserves |
| 762 | * __GFP_NOWARN: don't print a warning in case of failure |
| 763 | * |
| 764 | * For debugging, if we set the cache size to 1, no new buffers will |
| 765 | * be allocated. |
| 766 | */ |
| 767 | while (1) { |
| 768 | if (dm_bufio_cache_size_latch != 1) { |
| 769 | b = alloc_buffer(c, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); |
| 770 | if (b) |
| 771 | return b; |
| 772 | } |
| 773 | |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 774 | if (nf == NF_PREFETCH) |
| 775 | return NULL; |
| 776 | |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 777 | if (!list_empty(&c->reserved_buffers)) { |
| 778 | b = list_entry(c->reserved_buffers.next, |
| 779 | struct dm_buffer, lru_list); |
| 780 | list_del(&b->lru_list); |
| 781 | c->need_reserved_buffers++; |
| 782 | |
| 783 | return b; |
| 784 | } |
| 785 | |
| 786 | b = __get_unclaimed_buffer(c); |
| 787 | if (b) |
| 788 | return b; |
| 789 | |
| 790 | __wait_for_free_buffer(c); |
| 791 | } |
| 792 | } |
| 793 | |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 794 | static struct dm_buffer *__alloc_buffer_wait(struct dm_bufio_client *c, enum new_flag nf) |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 795 | { |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 796 | struct dm_buffer *b = __alloc_buffer_wait_no_callback(c, nf); |
| 797 | |
| 798 | if (!b) |
| 799 | return NULL; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 800 | |
| 801 | if (c->alloc_callback) |
| 802 | c->alloc_callback(b); |
| 803 | |
| 804 | return b; |
| 805 | } |
| 806 | |
| 807 | /* |
| 808 | * Free a buffer and wake other threads waiting for free buffers. |
| 809 | */ |
| 810 | static void __free_buffer_wake(struct dm_buffer *b) |
| 811 | { |
| 812 | struct dm_bufio_client *c = b->c; |
| 813 | |
| 814 | if (!c->need_reserved_buffers) |
| 815 | free_buffer(b); |
| 816 | else { |
| 817 | list_add(&b->lru_list, &c->reserved_buffers); |
| 818 | c->need_reserved_buffers--; |
| 819 | } |
| 820 | |
| 821 | wake_up(&c->free_buffer_wait); |
| 822 | } |
| 823 | |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 824 | static void __write_dirty_buffers_async(struct dm_bufio_client *c, int no_wait, |
| 825 | struct list_head *write_list) |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 826 | { |
| 827 | struct dm_buffer *b, *tmp; |
| 828 | |
| 829 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { |
| 830 | BUG_ON(test_bit(B_READING, &b->state)); |
| 831 | |
| 832 | if (!test_bit(B_DIRTY, &b->state) && |
| 833 | !test_bit(B_WRITING, &b->state)) { |
| 834 | __relink_lru(b, LIST_CLEAN); |
| 835 | continue; |
| 836 | } |
| 837 | |
| 838 | if (no_wait && test_bit(B_WRITING, &b->state)) |
| 839 | return; |
| 840 | |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 841 | __write_dirty_buffer(b, write_list); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 842 | dm_bufio_cond_resched(); |
| 843 | } |
| 844 | } |
| 845 | |
| 846 | /* |
| 847 | * Get writeback threshold and buffer limit for a given client. |
| 848 | */ |
| 849 | static void __get_memory_limit(struct dm_bufio_client *c, |
| 850 | unsigned long *threshold_buffers, |
| 851 | unsigned long *limit_buffers) |
| 852 | { |
| 853 | unsigned long buffers; |
| 854 | |
Mikulas Patocka | fe5fe90 | 2012-10-12 16:59:46 +0100 | [diff] [blame] | 855 | if (ACCESS_ONCE(dm_bufio_cache_size) != dm_bufio_cache_size_latch) { |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 856 | mutex_lock(&dm_bufio_clients_lock); |
| 857 | __cache_size_refresh(); |
| 858 | mutex_unlock(&dm_bufio_clients_lock); |
| 859 | } |
| 860 | |
| 861 | buffers = dm_bufio_cache_size_per_client >> |
| 862 | (c->sectors_per_block_bits + SECTOR_SHIFT); |
| 863 | |
| 864 | if (buffers < DM_BUFIO_MIN_BUFFERS) |
| 865 | buffers = DM_BUFIO_MIN_BUFFERS; |
| 866 | |
| 867 | *limit_buffers = buffers; |
| 868 | *threshold_buffers = buffers * DM_BUFIO_WRITEBACK_PERCENT / 100; |
| 869 | } |
| 870 | |
| 871 | /* |
| 872 | * Check if we're over watermark. |
| 873 | * If we are over threshold_buffers, start freeing buffers. |
| 874 | * If we're over "limit_buffers", block until we get under the limit. |
| 875 | */ |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 876 | static void __check_watermark(struct dm_bufio_client *c, |
| 877 | struct list_head *write_list) |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 878 | { |
| 879 | unsigned long threshold_buffers, limit_buffers; |
| 880 | |
| 881 | __get_memory_limit(c, &threshold_buffers, &limit_buffers); |
| 882 | |
| 883 | while (c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY] > |
| 884 | limit_buffers) { |
| 885 | |
| 886 | struct dm_buffer *b = __get_unclaimed_buffer(c); |
| 887 | |
| 888 | if (!b) |
| 889 | return; |
| 890 | |
| 891 | __free_buffer_wake(b); |
| 892 | dm_bufio_cond_resched(); |
| 893 | } |
| 894 | |
| 895 | if (c->n_buffers[LIST_DIRTY] > threshold_buffers) |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 896 | __write_dirty_buffers_async(c, 1, write_list); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 897 | } |
| 898 | |
| 899 | /* |
| 900 | * Find a buffer in the hash. |
| 901 | */ |
| 902 | static struct dm_buffer *__find(struct dm_bufio_client *c, sector_t block) |
| 903 | { |
| 904 | struct dm_buffer *b; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 905 | |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 906 | hlist_for_each_entry(b, &c->cache_hash[DM_BUFIO_HASH(block)], |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 907 | hash_list) { |
| 908 | dm_bufio_cond_resched(); |
| 909 | if (b->block == block) |
| 910 | return b; |
| 911 | } |
| 912 | |
| 913 | return NULL; |
| 914 | } |
| 915 | |
| 916 | /*---------------------------------------------------------------- |
| 917 | * Getting a buffer |
| 918 | *--------------------------------------------------------------*/ |
| 919 | |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 920 | static struct dm_buffer *__bufio_new(struct dm_bufio_client *c, sector_t block, |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 921 | enum new_flag nf, int *need_submit, |
| 922 | struct list_head *write_list) |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 923 | { |
| 924 | struct dm_buffer *b, *new_b = NULL; |
| 925 | |
| 926 | *need_submit = 0; |
| 927 | |
| 928 | b = __find(c, block); |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 929 | if (b) |
| 930 | goto found_buffer; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 931 | |
| 932 | if (nf == NF_GET) |
| 933 | return NULL; |
| 934 | |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 935 | new_b = __alloc_buffer_wait(c, nf); |
| 936 | if (!new_b) |
| 937 | return NULL; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 938 | |
| 939 | /* |
| 940 | * We've had a period where the mutex was unlocked, so need to |
| 941 | * recheck the hash table. |
| 942 | */ |
| 943 | b = __find(c, block); |
| 944 | if (b) { |
| 945 | __free_buffer_wake(new_b); |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 946 | goto found_buffer; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 947 | } |
| 948 | |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 949 | __check_watermark(c, write_list); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 950 | |
| 951 | b = new_b; |
| 952 | b->hold_count = 1; |
| 953 | b->read_error = 0; |
| 954 | b->write_error = 0; |
| 955 | __link_buffer(b, block, LIST_CLEAN); |
| 956 | |
| 957 | if (nf == NF_FRESH) { |
| 958 | b->state = 0; |
| 959 | return b; |
| 960 | } |
| 961 | |
| 962 | b->state = 1 << B_READING; |
| 963 | *need_submit = 1; |
| 964 | |
| 965 | return b; |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 966 | |
| 967 | found_buffer: |
| 968 | if (nf == NF_PREFETCH) |
| 969 | return NULL; |
| 970 | /* |
| 971 | * Note: it is essential that we don't wait for the buffer to be |
| 972 | * read if dm_bufio_get function is used. Both dm_bufio_get and |
| 973 | * dm_bufio_prefetch can be used in the driver request routine. |
| 974 | * If the user called both dm_bufio_prefetch and dm_bufio_get on |
| 975 | * the same buffer, it would deadlock if we waited. |
| 976 | */ |
| 977 | if (nf == NF_GET && unlikely(test_bit(B_READING, &b->state))) |
| 978 | return NULL; |
| 979 | |
| 980 | b->hold_count++; |
| 981 | __relink_lru(b, test_bit(B_DIRTY, &b->state) || |
| 982 | test_bit(B_WRITING, &b->state)); |
| 983 | return b; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 984 | } |
| 985 | |
| 986 | /* |
| 987 | * The endio routine for reading: set the error, clear the bit and wake up |
| 988 | * anyone waiting on the buffer. |
| 989 | */ |
| 990 | static void read_endio(struct bio *bio, int error) |
| 991 | { |
| 992 | struct dm_buffer *b = container_of(bio, struct dm_buffer, bio); |
| 993 | |
| 994 | b->read_error = error; |
| 995 | |
| 996 | BUG_ON(!test_bit(B_READING, &b->state)); |
| 997 | |
| 998 | smp_mb__before_clear_bit(); |
| 999 | clear_bit(B_READING, &b->state); |
| 1000 | smp_mb__after_clear_bit(); |
| 1001 | |
| 1002 | wake_up_bit(&b->state, B_READING); |
| 1003 | } |
| 1004 | |
| 1005 | /* |
| 1006 | * A common routine for dm_bufio_new and dm_bufio_read. Operation of these |
| 1007 | * functions is similar except that dm_bufio_new doesn't read the |
| 1008 | * buffer from the disk (assuming that the caller overwrites all the data |
| 1009 | * and uses dm_bufio_mark_buffer_dirty to write new data back). |
| 1010 | */ |
| 1011 | static void *new_read(struct dm_bufio_client *c, sector_t block, |
| 1012 | enum new_flag nf, struct dm_buffer **bp) |
| 1013 | { |
| 1014 | int need_submit; |
| 1015 | struct dm_buffer *b; |
| 1016 | |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 1017 | LIST_HEAD(write_list); |
| 1018 | |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1019 | dm_bufio_lock(c); |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 1020 | b = __bufio_new(c, block, nf, &need_submit, &write_list); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1021 | dm_bufio_unlock(c); |
| 1022 | |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 1023 | __flush_write_list(&write_list); |
| 1024 | |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 1025 | if (!b) |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1026 | return b; |
| 1027 | |
| 1028 | if (need_submit) |
| 1029 | submit_io(b, READ, b->block, read_endio); |
| 1030 | |
| 1031 | wait_on_bit(&b->state, B_READING, do_io_schedule, TASK_UNINTERRUPTIBLE); |
| 1032 | |
| 1033 | if (b->read_error) { |
| 1034 | int error = b->read_error; |
| 1035 | |
| 1036 | dm_bufio_release(b); |
| 1037 | |
| 1038 | return ERR_PTR(error); |
| 1039 | } |
| 1040 | |
| 1041 | *bp = b; |
| 1042 | |
| 1043 | return b->data; |
| 1044 | } |
| 1045 | |
| 1046 | void *dm_bufio_get(struct dm_bufio_client *c, sector_t block, |
| 1047 | struct dm_buffer **bp) |
| 1048 | { |
| 1049 | return new_read(c, block, NF_GET, bp); |
| 1050 | } |
| 1051 | EXPORT_SYMBOL_GPL(dm_bufio_get); |
| 1052 | |
| 1053 | void *dm_bufio_read(struct dm_bufio_client *c, sector_t block, |
| 1054 | struct dm_buffer **bp) |
| 1055 | { |
| 1056 | BUG_ON(dm_bufio_in_request()); |
| 1057 | |
| 1058 | return new_read(c, block, NF_READ, bp); |
| 1059 | } |
| 1060 | EXPORT_SYMBOL_GPL(dm_bufio_read); |
| 1061 | |
| 1062 | void *dm_bufio_new(struct dm_bufio_client *c, sector_t block, |
| 1063 | struct dm_buffer **bp) |
| 1064 | { |
| 1065 | BUG_ON(dm_bufio_in_request()); |
| 1066 | |
| 1067 | return new_read(c, block, NF_FRESH, bp); |
| 1068 | } |
| 1069 | EXPORT_SYMBOL_GPL(dm_bufio_new); |
| 1070 | |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 1071 | void dm_bufio_prefetch(struct dm_bufio_client *c, |
| 1072 | sector_t block, unsigned n_blocks) |
| 1073 | { |
| 1074 | struct blk_plug plug; |
| 1075 | |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 1076 | LIST_HEAD(write_list); |
| 1077 | |
Mikulas Patocka | 3b6b781 | 2013-03-20 17:21:25 +0000 | [diff] [blame] | 1078 | BUG_ON(dm_bufio_in_request()); |
| 1079 | |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 1080 | blk_start_plug(&plug); |
| 1081 | dm_bufio_lock(c); |
| 1082 | |
| 1083 | for (; n_blocks--; block++) { |
| 1084 | int need_submit; |
| 1085 | struct dm_buffer *b; |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 1086 | b = __bufio_new(c, block, NF_PREFETCH, &need_submit, |
| 1087 | &write_list); |
| 1088 | if (unlikely(!list_empty(&write_list))) { |
| 1089 | dm_bufio_unlock(c); |
| 1090 | blk_finish_plug(&plug); |
| 1091 | __flush_write_list(&write_list); |
| 1092 | blk_start_plug(&plug); |
| 1093 | dm_bufio_lock(c); |
| 1094 | } |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 1095 | if (unlikely(b != NULL)) { |
| 1096 | dm_bufio_unlock(c); |
| 1097 | |
| 1098 | if (need_submit) |
| 1099 | submit_io(b, READ, b->block, read_endio); |
| 1100 | dm_bufio_release(b); |
| 1101 | |
| 1102 | dm_bufio_cond_resched(); |
| 1103 | |
| 1104 | if (!n_blocks) |
| 1105 | goto flush_plug; |
| 1106 | dm_bufio_lock(c); |
| 1107 | } |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 1108 | } |
| 1109 | |
| 1110 | dm_bufio_unlock(c); |
| 1111 | |
| 1112 | flush_plug: |
| 1113 | blk_finish_plug(&plug); |
| 1114 | } |
| 1115 | EXPORT_SYMBOL_GPL(dm_bufio_prefetch); |
| 1116 | |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1117 | void dm_bufio_release(struct dm_buffer *b) |
| 1118 | { |
| 1119 | struct dm_bufio_client *c = b->c; |
| 1120 | |
| 1121 | dm_bufio_lock(c); |
| 1122 | |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1123 | BUG_ON(!b->hold_count); |
| 1124 | |
| 1125 | b->hold_count--; |
| 1126 | if (!b->hold_count) { |
| 1127 | wake_up(&c->free_buffer_wait); |
| 1128 | |
| 1129 | /* |
| 1130 | * If there were errors on the buffer, and the buffer is not |
| 1131 | * to be written, free the buffer. There is no point in caching |
| 1132 | * invalid buffer. |
| 1133 | */ |
| 1134 | if ((b->read_error || b->write_error) && |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 1135 | !test_bit(B_READING, &b->state) && |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1136 | !test_bit(B_WRITING, &b->state) && |
| 1137 | !test_bit(B_DIRTY, &b->state)) { |
| 1138 | __unlink_buffer(b); |
| 1139 | __free_buffer_wake(b); |
| 1140 | } |
| 1141 | } |
| 1142 | |
| 1143 | dm_bufio_unlock(c); |
| 1144 | } |
| 1145 | EXPORT_SYMBOL_GPL(dm_bufio_release); |
| 1146 | |
| 1147 | void dm_bufio_mark_buffer_dirty(struct dm_buffer *b) |
| 1148 | { |
| 1149 | struct dm_bufio_client *c = b->c; |
| 1150 | |
| 1151 | dm_bufio_lock(c); |
| 1152 | |
Mikulas Patocka | a66cc28 | 2012-03-28 18:41:29 +0100 | [diff] [blame] | 1153 | BUG_ON(test_bit(B_READING, &b->state)); |
| 1154 | |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1155 | if (!test_and_set_bit(B_DIRTY, &b->state)) |
| 1156 | __relink_lru(b, LIST_DIRTY); |
| 1157 | |
| 1158 | dm_bufio_unlock(c); |
| 1159 | } |
| 1160 | EXPORT_SYMBOL_GPL(dm_bufio_mark_buffer_dirty); |
| 1161 | |
| 1162 | void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c) |
| 1163 | { |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 1164 | LIST_HEAD(write_list); |
| 1165 | |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1166 | BUG_ON(dm_bufio_in_request()); |
| 1167 | |
| 1168 | dm_bufio_lock(c); |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 1169 | __write_dirty_buffers_async(c, 0, &write_list); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1170 | dm_bufio_unlock(c); |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 1171 | __flush_write_list(&write_list); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1172 | } |
| 1173 | EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers_async); |
| 1174 | |
| 1175 | /* |
| 1176 | * For performance, it is essential that the buffers are written asynchronously |
| 1177 | * and simultaneously (so that the block layer can merge the writes) and then |
| 1178 | * waited upon. |
| 1179 | * |
| 1180 | * Finally, we flush hardware disk cache. |
| 1181 | */ |
| 1182 | int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c) |
| 1183 | { |
| 1184 | int a, f; |
| 1185 | unsigned long buffers_processed = 0; |
| 1186 | struct dm_buffer *b, *tmp; |
| 1187 | |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 1188 | LIST_HEAD(write_list); |
| 1189 | |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1190 | dm_bufio_lock(c); |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 1191 | __write_dirty_buffers_async(c, 0, &write_list); |
| 1192 | dm_bufio_unlock(c); |
| 1193 | __flush_write_list(&write_list); |
| 1194 | dm_bufio_lock(c); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1195 | |
| 1196 | again: |
| 1197 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_DIRTY], lru_list) { |
| 1198 | int dropped_lock = 0; |
| 1199 | |
| 1200 | if (buffers_processed < c->n_buffers[LIST_DIRTY]) |
| 1201 | buffers_processed++; |
| 1202 | |
| 1203 | BUG_ON(test_bit(B_READING, &b->state)); |
| 1204 | |
| 1205 | if (test_bit(B_WRITING, &b->state)) { |
| 1206 | if (buffers_processed < c->n_buffers[LIST_DIRTY]) { |
| 1207 | dropped_lock = 1; |
| 1208 | b->hold_count++; |
| 1209 | dm_bufio_unlock(c); |
| 1210 | wait_on_bit(&b->state, B_WRITING, |
| 1211 | do_io_schedule, |
| 1212 | TASK_UNINTERRUPTIBLE); |
| 1213 | dm_bufio_lock(c); |
| 1214 | b->hold_count--; |
| 1215 | } else |
| 1216 | wait_on_bit(&b->state, B_WRITING, |
| 1217 | do_io_schedule, |
| 1218 | TASK_UNINTERRUPTIBLE); |
| 1219 | } |
| 1220 | |
| 1221 | if (!test_bit(B_DIRTY, &b->state) && |
| 1222 | !test_bit(B_WRITING, &b->state)) |
| 1223 | __relink_lru(b, LIST_CLEAN); |
| 1224 | |
| 1225 | dm_bufio_cond_resched(); |
| 1226 | |
| 1227 | /* |
| 1228 | * If we dropped the lock, the list is no longer consistent, |
| 1229 | * so we must restart the search. |
| 1230 | * |
| 1231 | * In the most common case, the buffer just processed is |
| 1232 | * relinked to the clean list, so we won't loop scanning the |
| 1233 | * same buffer again and again. |
| 1234 | * |
| 1235 | * This may livelock if there is another thread simultaneously |
| 1236 | * dirtying buffers, so we count the number of buffers walked |
| 1237 | * and if it exceeds the total number of buffers, it means that |
| 1238 | * someone is doing some writes simultaneously with us. In |
| 1239 | * this case, stop, dropping the lock. |
| 1240 | */ |
| 1241 | if (dropped_lock) |
| 1242 | goto again; |
| 1243 | } |
| 1244 | wake_up(&c->free_buffer_wait); |
| 1245 | dm_bufio_unlock(c); |
| 1246 | |
| 1247 | a = xchg(&c->async_write_error, 0); |
| 1248 | f = dm_bufio_issue_flush(c); |
| 1249 | if (a) |
| 1250 | return a; |
| 1251 | |
| 1252 | return f; |
| 1253 | } |
| 1254 | EXPORT_SYMBOL_GPL(dm_bufio_write_dirty_buffers); |
| 1255 | |
| 1256 | /* |
| 1257 | * Use dm-io to send and empty barrier flush the device. |
| 1258 | */ |
| 1259 | int dm_bufio_issue_flush(struct dm_bufio_client *c) |
| 1260 | { |
| 1261 | struct dm_io_request io_req = { |
Mikulas Patocka | 3daec3b | 2013-03-01 22:45:45 +0000 | [diff] [blame] | 1262 | .bi_rw = WRITE_FLUSH, |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1263 | .mem.type = DM_IO_KMEM, |
| 1264 | .mem.ptr.addr = NULL, |
| 1265 | .client = c->dm_io, |
| 1266 | }; |
| 1267 | struct dm_io_region io_reg = { |
| 1268 | .bdev = c->bdev, |
| 1269 | .sector = 0, |
| 1270 | .count = 0, |
| 1271 | }; |
| 1272 | |
| 1273 | BUG_ON(dm_bufio_in_request()); |
| 1274 | |
| 1275 | return dm_io(&io_req, 1, &io_reg, NULL); |
| 1276 | } |
| 1277 | EXPORT_SYMBOL_GPL(dm_bufio_issue_flush); |
| 1278 | |
| 1279 | /* |
| 1280 | * We first delete any other buffer that may be at that new location. |
| 1281 | * |
| 1282 | * Then, we write the buffer to the original location if it was dirty. |
| 1283 | * |
| 1284 | * Then, if we are the only one who is holding the buffer, relink the buffer |
| 1285 | * in the hash queue for the new location. |
| 1286 | * |
| 1287 | * If there was someone else holding the buffer, we write it to the new |
| 1288 | * location but not relink it, because that other user needs to have the buffer |
| 1289 | * at the same place. |
| 1290 | */ |
| 1291 | void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block) |
| 1292 | { |
| 1293 | struct dm_bufio_client *c = b->c; |
| 1294 | struct dm_buffer *new; |
| 1295 | |
| 1296 | BUG_ON(dm_bufio_in_request()); |
| 1297 | |
| 1298 | dm_bufio_lock(c); |
| 1299 | |
| 1300 | retry: |
| 1301 | new = __find(c, new_block); |
| 1302 | if (new) { |
| 1303 | if (new->hold_count) { |
| 1304 | __wait_for_free_buffer(c); |
| 1305 | goto retry; |
| 1306 | } |
| 1307 | |
| 1308 | /* |
| 1309 | * FIXME: Is there any point waiting for a write that's going |
| 1310 | * to be overwritten in a bit? |
| 1311 | */ |
| 1312 | __make_buffer_clean(new); |
| 1313 | __unlink_buffer(new); |
| 1314 | __free_buffer_wake(new); |
| 1315 | } |
| 1316 | |
| 1317 | BUG_ON(!b->hold_count); |
| 1318 | BUG_ON(test_bit(B_READING, &b->state)); |
| 1319 | |
Mikulas Patocka | 2480945 | 2013-07-10 23:41:18 +0100 | [diff] [blame] | 1320 | __write_dirty_buffer(b, NULL); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1321 | if (b->hold_count == 1) { |
| 1322 | wait_on_bit(&b->state, B_WRITING, |
| 1323 | do_io_schedule, TASK_UNINTERRUPTIBLE); |
| 1324 | set_bit(B_DIRTY, &b->state); |
| 1325 | __unlink_buffer(b); |
| 1326 | __link_buffer(b, new_block, LIST_DIRTY); |
| 1327 | } else { |
| 1328 | sector_t old_block; |
| 1329 | wait_on_bit_lock(&b->state, B_WRITING, |
| 1330 | do_io_schedule, TASK_UNINTERRUPTIBLE); |
| 1331 | /* |
| 1332 | * Relink buffer to "new_block" so that write_callback |
| 1333 | * sees "new_block" as a block number. |
| 1334 | * After the write, link the buffer back to old_block. |
| 1335 | * All this must be done in bufio lock, so that block number |
| 1336 | * change isn't visible to other threads. |
| 1337 | */ |
| 1338 | old_block = b->block; |
| 1339 | __unlink_buffer(b); |
| 1340 | __link_buffer(b, new_block, b->list_mode); |
| 1341 | submit_io(b, WRITE, new_block, write_endio); |
| 1342 | wait_on_bit(&b->state, B_WRITING, |
| 1343 | do_io_schedule, TASK_UNINTERRUPTIBLE); |
| 1344 | __unlink_buffer(b); |
| 1345 | __link_buffer(b, old_block, b->list_mode); |
| 1346 | } |
| 1347 | |
| 1348 | dm_bufio_unlock(c); |
| 1349 | dm_bufio_release(b); |
| 1350 | } |
| 1351 | EXPORT_SYMBOL_GPL(dm_bufio_release_move); |
| 1352 | |
| 1353 | unsigned dm_bufio_get_block_size(struct dm_bufio_client *c) |
| 1354 | { |
| 1355 | return c->block_size; |
| 1356 | } |
| 1357 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_size); |
| 1358 | |
| 1359 | sector_t dm_bufio_get_device_size(struct dm_bufio_client *c) |
| 1360 | { |
| 1361 | return i_size_read(c->bdev->bd_inode) >> |
| 1362 | (SECTOR_SHIFT + c->sectors_per_block_bits); |
| 1363 | } |
| 1364 | EXPORT_SYMBOL_GPL(dm_bufio_get_device_size); |
| 1365 | |
| 1366 | sector_t dm_bufio_get_block_number(struct dm_buffer *b) |
| 1367 | { |
| 1368 | return b->block; |
| 1369 | } |
| 1370 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_number); |
| 1371 | |
| 1372 | void *dm_bufio_get_block_data(struct dm_buffer *b) |
| 1373 | { |
| 1374 | return b->data; |
| 1375 | } |
| 1376 | EXPORT_SYMBOL_GPL(dm_bufio_get_block_data); |
| 1377 | |
| 1378 | void *dm_bufio_get_aux_data(struct dm_buffer *b) |
| 1379 | { |
| 1380 | return b + 1; |
| 1381 | } |
| 1382 | EXPORT_SYMBOL_GPL(dm_bufio_get_aux_data); |
| 1383 | |
| 1384 | struct dm_bufio_client *dm_bufio_get_client(struct dm_buffer *b) |
| 1385 | { |
| 1386 | return b->c; |
| 1387 | } |
| 1388 | EXPORT_SYMBOL_GPL(dm_bufio_get_client); |
| 1389 | |
| 1390 | static void drop_buffers(struct dm_bufio_client *c) |
| 1391 | { |
| 1392 | struct dm_buffer *b; |
| 1393 | int i; |
| 1394 | |
| 1395 | BUG_ON(dm_bufio_in_request()); |
| 1396 | |
| 1397 | /* |
| 1398 | * An optimization so that the buffers are not written one-by-one. |
| 1399 | */ |
| 1400 | dm_bufio_write_dirty_buffers_async(c); |
| 1401 | |
| 1402 | dm_bufio_lock(c); |
| 1403 | |
| 1404 | while ((b = __get_unclaimed_buffer(c))) |
| 1405 | __free_buffer_wake(b); |
| 1406 | |
| 1407 | for (i = 0; i < LIST_SIZE; i++) |
| 1408 | list_for_each_entry(b, &c->lru[i], lru_list) |
| 1409 | DMERR("leaked buffer %llx, hold count %u, list %d", |
| 1410 | (unsigned long long)b->block, b->hold_count, i); |
| 1411 | |
| 1412 | for (i = 0; i < LIST_SIZE; i++) |
| 1413 | BUG_ON(!list_empty(&c->lru[i])); |
| 1414 | |
| 1415 | dm_bufio_unlock(c); |
| 1416 | } |
| 1417 | |
| 1418 | /* |
| 1419 | * Test if the buffer is unused and too old, and commit it. |
| 1420 | * At if noio is set, we must not do any I/O because we hold |
| 1421 | * dm_bufio_clients_lock and we would risk deadlock if the I/O gets rerouted to |
| 1422 | * different bufio client. |
| 1423 | */ |
| 1424 | static int __cleanup_old_buffer(struct dm_buffer *b, gfp_t gfp, |
| 1425 | unsigned long max_jiffies) |
| 1426 | { |
| 1427 | if (jiffies - b->last_accessed < max_jiffies) |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1428 | return 0; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1429 | |
| 1430 | if (!(gfp & __GFP_IO)) { |
| 1431 | if (test_bit(B_READING, &b->state) || |
| 1432 | test_bit(B_WRITING, &b->state) || |
| 1433 | test_bit(B_DIRTY, &b->state)) |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1434 | return 0; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1435 | } |
| 1436 | |
| 1437 | if (b->hold_count) |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1438 | return 0; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1439 | |
| 1440 | __make_buffer_clean(b); |
| 1441 | __unlink_buffer(b); |
| 1442 | __free_buffer_wake(b); |
| 1443 | |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1444 | return 1; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1445 | } |
| 1446 | |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1447 | static long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan, |
| 1448 | gfp_t gfp_mask) |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1449 | { |
| 1450 | int l; |
| 1451 | struct dm_buffer *b, *tmp; |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1452 | long freed = 0; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1453 | |
| 1454 | for (l = 0; l < LIST_SIZE; l++) { |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1455 | list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list) { |
| 1456 | freed += __cleanup_old_buffer(b, gfp_mask, 0); |
| 1457 | if (!--nr_to_scan) |
| 1458 | break; |
| 1459 | } |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1460 | dm_bufio_cond_resched(); |
| 1461 | } |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1462 | return freed; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1463 | } |
| 1464 | |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1465 | static unsigned long |
| 1466 | dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1467 | { |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1468 | struct dm_bufio_client *c; |
| 1469 | unsigned long freed; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1470 | |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1471 | c = container_of(shrink, struct dm_bufio_client, shrinker); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1472 | if (sc->gfp_mask & __GFP_IO) |
| 1473 | dm_bufio_lock(c); |
| 1474 | else if (!dm_bufio_trylock(c)) |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1475 | return SHRINK_STOP; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1476 | |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1477 | freed = __scan(c, sc->nr_to_scan, sc->gfp_mask); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1478 | dm_bufio_unlock(c); |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1479 | return freed; |
| 1480 | } |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1481 | |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1482 | static unsigned long |
| 1483 | dm_bufio_shrink_count(struct shrinker *shrink, struct shrink_control *sc) |
| 1484 | { |
| 1485 | struct dm_bufio_client *c; |
| 1486 | unsigned long count; |
| 1487 | |
| 1488 | c = container_of(shrink, struct dm_bufio_client, shrinker); |
| 1489 | if (sc->gfp_mask & __GFP_IO) |
| 1490 | dm_bufio_lock(c); |
| 1491 | else if (!dm_bufio_trylock(c)) |
| 1492 | return 0; |
| 1493 | |
| 1494 | count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY]; |
| 1495 | dm_bufio_unlock(c); |
| 1496 | return count; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1497 | } |
| 1498 | |
| 1499 | /* |
| 1500 | * Create the buffering interface |
| 1501 | */ |
| 1502 | struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsigned block_size, |
| 1503 | unsigned reserved_buffers, unsigned aux_size, |
| 1504 | void (*alloc_callback)(struct dm_buffer *), |
| 1505 | void (*write_callback)(struct dm_buffer *)) |
| 1506 | { |
| 1507 | int r; |
| 1508 | struct dm_bufio_client *c; |
| 1509 | unsigned i; |
| 1510 | |
| 1511 | BUG_ON(block_size < 1 << SECTOR_SHIFT || |
| 1512 | (block_size & (block_size - 1))); |
| 1513 | |
| 1514 | c = kmalloc(sizeof(*c), GFP_KERNEL); |
| 1515 | if (!c) { |
| 1516 | r = -ENOMEM; |
| 1517 | goto bad_client; |
| 1518 | } |
| 1519 | c->cache_hash = vmalloc(sizeof(struct hlist_head) << DM_BUFIO_HASH_BITS); |
| 1520 | if (!c->cache_hash) { |
| 1521 | r = -ENOMEM; |
| 1522 | goto bad_hash; |
| 1523 | } |
| 1524 | |
| 1525 | c->bdev = bdev; |
| 1526 | c->block_size = block_size; |
| 1527 | c->sectors_per_block_bits = ffs(block_size) - 1 - SECTOR_SHIFT; |
| 1528 | c->pages_per_block_bits = (ffs(block_size) - 1 >= PAGE_SHIFT) ? |
| 1529 | ffs(block_size) - 1 - PAGE_SHIFT : 0; |
| 1530 | c->blocks_per_page_bits = (ffs(block_size) - 1 < PAGE_SHIFT ? |
| 1531 | PAGE_SHIFT - (ffs(block_size) - 1) : 0); |
| 1532 | |
| 1533 | c->aux_size = aux_size; |
| 1534 | c->alloc_callback = alloc_callback; |
| 1535 | c->write_callback = write_callback; |
| 1536 | |
| 1537 | for (i = 0; i < LIST_SIZE; i++) { |
| 1538 | INIT_LIST_HEAD(&c->lru[i]); |
| 1539 | c->n_buffers[i] = 0; |
| 1540 | } |
| 1541 | |
| 1542 | for (i = 0; i < 1 << DM_BUFIO_HASH_BITS; i++) |
| 1543 | INIT_HLIST_HEAD(&c->cache_hash[i]); |
| 1544 | |
| 1545 | mutex_init(&c->lock); |
| 1546 | INIT_LIST_HEAD(&c->reserved_buffers); |
| 1547 | c->need_reserved_buffers = reserved_buffers; |
| 1548 | |
| 1549 | init_waitqueue_head(&c->free_buffer_wait); |
| 1550 | c->async_write_error = 0; |
| 1551 | |
| 1552 | c->dm_io = dm_io_client_create(); |
| 1553 | if (IS_ERR(c->dm_io)) { |
| 1554 | r = PTR_ERR(c->dm_io); |
| 1555 | goto bad_dm_io; |
| 1556 | } |
| 1557 | |
| 1558 | mutex_lock(&dm_bufio_clients_lock); |
| 1559 | if (c->blocks_per_page_bits) { |
| 1560 | if (!DM_BUFIO_CACHE_NAME(c)) { |
| 1561 | DM_BUFIO_CACHE_NAME(c) = kasprintf(GFP_KERNEL, "dm_bufio_cache-%u", c->block_size); |
| 1562 | if (!DM_BUFIO_CACHE_NAME(c)) { |
| 1563 | r = -ENOMEM; |
| 1564 | mutex_unlock(&dm_bufio_clients_lock); |
| 1565 | goto bad_cache; |
| 1566 | } |
| 1567 | } |
| 1568 | |
| 1569 | if (!DM_BUFIO_CACHE(c)) { |
| 1570 | DM_BUFIO_CACHE(c) = kmem_cache_create(DM_BUFIO_CACHE_NAME(c), |
| 1571 | c->block_size, |
| 1572 | c->block_size, 0, NULL); |
| 1573 | if (!DM_BUFIO_CACHE(c)) { |
| 1574 | r = -ENOMEM; |
| 1575 | mutex_unlock(&dm_bufio_clients_lock); |
| 1576 | goto bad_cache; |
| 1577 | } |
| 1578 | } |
| 1579 | } |
| 1580 | mutex_unlock(&dm_bufio_clients_lock); |
| 1581 | |
| 1582 | while (c->need_reserved_buffers) { |
| 1583 | struct dm_buffer *b = alloc_buffer(c, GFP_KERNEL); |
| 1584 | |
| 1585 | if (!b) { |
| 1586 | r = -ENOMEM; |
| 1587 | goto bad_buffer; |
| 1588 | } |
| 1589 | __free_buffer_wake(b); |
| 1590 | } |
| 1591 | |
| 1592 | mutex_lock(&dm_bufio_clients_lock); |
| 1593 | dm_bufio_client_count++; |
| 1594 | list_add(&c->client_list, &dm_bufio_all_clients); |
| 1595 | __cache_size_refresh(); |
| 1596 | mutex_unlock(&dm_bufio_clients_lock); |
| 1597 | |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1598 | c->shrinker.count_objects = dm_bufio_shrink_count; |
| 1599 | c->shrinker.scan_objects = dm_bufio_shrink_scan; |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1600 | c->shrinker.seeks = 1; |
| 1601 | c->shrinker.batch = 0; |
| 1602 | register_shrinker(&c->shrinker); |
| 1603 | |
| 1604 | return c; |
| 1605 | |
| 1606 | bad_buffer: |
| 1607 | bad_cache: |
| 1608 | while (!list_empty(&c->reserved_buffers)) { |
| 1609 | struct dm_buffer *b = list_entry(c->reserved_buffers.next, |
| 1610 | struct dm_buffer, lru_list); |
| 1611 | list_del(&b->lru_list); |
| 1612 | free_buffer(b); |
| 1613 | } |
| 1614 | dm_io_client_destroy(c->dm_io); |
| 1615 | bad_dm_io: |
| 1616 | vfree(c->cache_hash); |
| 1617 | bad_hash: |
| 1618 | kfree(c); |
| 1619 | bad_client: |
| 1620 | return ERR_PTR(r); |
| 1621 | } |
| 1622 | EXPORT_SYMBOL_GPL(dm_bufio_client_create); |
| 1623 | |
| 1624 | /* |
| 1625 | * Free the buffering interface. |
| 1626 | * It is required that there are no references on any buffers. |
| 1627 | */ |
| 1628 | void dm_bufio_client_destroy(struct dm_bufio_client *c) |
| 1629 | { |
| 1630 | unsigned i; |
| 1631 | |
| 1632 | drop_buffers(c); |
| 1633 | |
| 1634 | unregister_shrinker(&c->shrinker); |
| 1635 | |
| 1636 | mutex_lock(&dm_bufio_clients_lock); |
| 1637 | |
| 1638 | list_del(&c->client_list); |
| 1639 | dm_bufio_client_count--; |
| 1640 | __cache_size_refresh(); |
| 1641 | |
| 1642 | mutex_unlock(&dm_bufio_clients_lock); |
| 1643 | |
| 1644 | for (i = 0; i < 1 << DM_BUFIO_HASH_BITS; i++) |
| 1645 | BUG_ON(!hlist_empty(&c->cache_hash[i])); |
| 1646 | |
| 1647 | BUG_ON(c->need_reserved_buffers); |
| 1648 | |
| 1649 | while (!list_empty(&c->reserved_buffers)) { |
| 1650 | struct dm_buffer *b = list_entry(c->reserved_buffers.next, |
| 1651 | struct dm_buffer, lru_list); |
| 1652 | list_del(&b->lru_list); |
| 1653 | free_buffer(b); |
| 1654 | } |
| 1655 | |
| 1656 | for (i = 0; i < LIST_SIZE; i++) |
| 1657 | if (c->n_buffers[i]) |
| 1658 | DMERR("leaked buffer count %d: %ld", i, c->n_buffers[i]); |
| 1659 | |
| 1660 | for (i = 0; i < LIST_SIZE; i++) |
| 1661 | BUG_ON(c->n_buffers[i]); |
| 1662 | |
| 1663 | dm_io_client_destroy(c->dm_io); |
| 1664 | vfree(c->cache_hash); |
| 1665 | kfree(c); |
| 1666 | } |
| 1667 | EXPORT_SYMBOL_GPL(dm_bufio_client_destroy); |
| 1668 | |
| 1669 | static void cleanup_old_buffers(void) |
| 1670 | { |
Mikulas Patocka | fe5fe90 | 2012-10-12 16:59:46 +0100 | [diff] [blame] | 1671 | unsigned long max_age = ACCESS_ONCE(dm_bufio_max_age); |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1672 | struct dm_bufio_client *c; |
| 1673 | |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1674 | if (max_age > ULONG_MAX / HZ) |
| 1675 | max_age = ULONG_MAX / HZ; |
| 1676 | |
| 1677 | mutex_lock(&dm_bufio_clients_lock); |
| 1678 | list_for_each_entry(c, &dm_bufio_all_clients, client_list) { |
| 1679 | if (!dm_bufio_trylock(c)) |
| 1680 | continue; |
| 1681 | |
| 1682 | while (!list_empty(&c->lru[LIST_CLEAN])) { |
| 1683 | struct dm_buffer *b; |
| 1684 | b = list_entry(c->lru[LIST_CLEAN].prev, |
| 1685 | struct dm_buffer, lru_list); |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 1686 | if (!__cleanup_old_buffer(b, 0, max_age * HZ)) |
Mikulas Patocka | 95d402f | 2011-10-31 20:19:09 +0000 | [diff] [blame] | 1687 | break; |
| 1688 | dm_bufio_cond_resched(); |
| 1689 | } |
| 1690 | |
| 1691 | dm_bufio_unlock(c); |
| 1692 | dm_bufio_cond_resched(); |
| 1693 | } |
| 1694 | mutex_unlock(&dm_bufio_clients_lock); |
| 1695 | } |
| 1696 | |
| 1697 | static struct workqueue_struct *dm_bufio_wq; |
| 1698 | static struct delayed_work dm_bufio_work; |
| 1699 | |
| 1700 | static void work_fn(struct work_struct *w) |
| 1701 | { |
| 1702 | cleanup_old_buffers(); |
| 1703 | |
| 1704 | queue_delayed_work(dm_bufio_wq, &dm_bufio_work, |
| 1705 | DM_BUFIO_WORK_TIMER_SECS * HZ); |
| 1706 | } |
| 1707 | |
| 1708 | /*---------------------------------------------------------------- |
| 1709 | * Module setup |
| 1710 | *--------------------------------------------------------------*/ |
| 1711 | |
| 1712 | /* |
| 1713 | * This is called only once for the whole dm_bufio module. |
| 1714 | * It initializes memory limit. |
| 1715 | */ |
| 1716 | static int __init dm_bufio_init(void) |
| 1717 | { |
| 1718 | __u64 mem; |
| 1719 | |
| 1720 | memset(&dm_bufio_caches, 0, sizeof dm_bufio_caches); |
| 1721 | memset(&dm_bufio_cache_names, 0, sizeof dm_bufio_cache_names); |
| 1722 | |
| 1723 | mem = (__u64)((totalram_pages - totalhigh_pages) * |
| 1724 | DM_BUFIO_MEMORY_PERCENT / 100) << PAGE_SHIFT; |
| 1725 | |
| 1726 | if (mem > ULONG_MAX) |
| 1727 | mem = ULONG_MAX; |
| 1728 | |
| 1729 | #ifdef CONFIG_MMU |
| 1730 | /* |
| 1731 | * Get the size of vmalloc space the same way as VMALLOC_TOTAL |
| 1732 | * in fs/proc/internal.h |
| 1733 | */ |
| 1734 | if (mem > (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100) |
| 1735 | mem = (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100; |
| 1736 | #endif |
| 1737 | |
| 1738 | dm_bufio_default_cache_size = mem; |
| 1739 | |
| 1740 | mutex_lock(&dm_bufio_clients_lock); |
| 1741 | __cache_size_refresh(); |
| 1742 | mutex_unlock(&dm_bufio_clients_lock); |
| 1743 | |
| 1744 | dm_bufio_wq = create_singlethread_workqueue("dm_bufio_cache"); |
| 1745 | if (!dm_bufio_wq) |
| 1746 | return -ENOMEM; |
| 1747 | |
| 1748 | INIT_DELAYED_WORK(&dm_bufio_work, work_fn); |
| 1749 | queue_delayed_work(dm_bufio_wq, &dm_bufio_work, |
| 1750 | DM_BUFIO_WORK_TIMER_SECS * HZ); |
| 1751 | |
| 1752 | return 0; |
| 1753 | } |
| 1754 | |
| 1755 | /* |
| 1756 | * This is called once when unloading the dm_bufio module. |
| 1757 | */ |
| 1758 | static void __exit dm_bufio_exit(void) |
| 1759 | { |
| 1760 | int bug = 0; |
| 1761 | int i; |
| 1762 | |
| 1763 | cancel_delayed_work_sync(&dm_bufio_work); |
| 1764 | destroy_workqueue(dm_bufio_wq); |
| 1765 | |
| 1766 | for (i = 0; i < ARRAY_SIZE(dm_bufio_caches); i++) { |
| 1767 | struct kmem_cache *kc = dm_bufio_caches[i]; |
| 1768 | |
| 1769 | if (kc) |
| 1770 | kmem_cache_destroy(kc); |
| 1771 | } |
| 1772 | |
| 1773 | for (i = 0; i < ARRAY_SIZE(dm_bufio_cache_names); i++) |
| 1774 | kfree(dm_bufio_cache_names[i]); |
| 1775 | |
| 1776 | if (dm_bufio_client_count) { |
| 1777 | DMCRIT("%s: dm_bufio_client_count leaked: %d", |
| 1778 | __func__, dm_bufio_client_count); |
| 1779 | bug = 1; |
| 1780 | } |
| 1781 | |
| 1782 | if (dm_bufio_current_allocated) { |
| 1783 | DMCRIT("%s: dm_bufio_current_allocated leaked: %lu", |
| 1784 | __func__, dm_bufio_current_allocated); |
| 1785 | bug = 1; |
| 1786 | } |
| 1787 | |
| 1788 | if (dm_bufio_allocated_get_free_pages) { |
| 1789 | DMCRIT("%s: dm_bufio_allocated_get_free_pages leaked: %lu", |
| 1790 | __func__, dm_bufio_allocated_get_free_pages); |
| 1791 | bug = 1; |
| 1792 | } |
| 1793 | |
| 1794 | if (dm_bufio_allocated_vmalloc) { |
| 1795 | DMCRIT("%s: dm_bufio_vmalloc leaked: %lu", |
| 1796 | __func__, dm_bufio_allocated_vmalloc); |
| 1797 | bug = 1; |
| 1798 | } |
| 1799 | |
| 1800 | if (bug) |
| 1801 | BUG(); |
| 1802 | } |
| 1803 | |
| 1804 | module_init(dm_bufio_init) |
| 1805 | module_exit(dm_bufio_exit) |
| 1806 | |
| 1807 | module_param_named(max_cache_size_bytes, dm_bufio_cache_size, ulong, S_IRUGO | S_IWUSR); |
| 1808 | MODULE_PARM_DESC(max_cache_size_bytes, "Size of metadata cache"); |
| 1809 | |
| 1810 | module_param_named(max_age_seconds, dm_bufio_max_age, uint, S_IRUGO | S_IWUSR); |
| 1811 | MODULE_PARM_DESC(max_age_seconds, "Max age of a buffer in seconds"); |
| 1812 | |
| 1813 | module_param_named(peak_allocated_bytes, dm_bufio_peak_allocated, ulong, S_IRUGO | S_IWUSR); |
| 1814 | MODULE_PARM_DESC(peak_allocated_bytes, "Tracks the maximum allocated memory"); |
| 1815 | |
| 1816 | module_param_named(allocated_kmem_cache_bytes, dm_bufio_allocated_kmem_cache, ulong, S_IRUGO); |
| 1817 | MODULE_PARM_DESC(allocated_kmem_cache_bytes, "Memory allocated with kmem_cache_alloc"); |
| 1818 | |
| 1819 | module_param_named(allocated_get_free_pages_bytes, dm_bufio_allocated_get_free_pages, ulong, S_IRUGO); |
| 1820 | MODULE_PARM_DESC(allocated_get_free_pages_bytes, "Memory allocated with get_free_pages"); |
| 1821 | |
| 1822 | module_param_named(allocated_vmalloc_bytes, dm_bufio_allocated_vmalloc, ulong, S_IRUGO); |
| 1823 | MODULE_PARM_DESC(allocated_vmalloc_bytes, "Memory allocated with vmalloc"); |
| 1824 | |
| 1825 | module_param_named(current_allocated_bytes, dm_bufio_current_allocated, ulong, S_IRUGO); |
| 1826 | MODULE_PARM_DESC(current_allocated_bytes, "Memory currently used by the cache"); |
| 1827 | |
| 1828 | MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>"); |
| 1829 | MODULE_DESCRIPTION(DM_NAME " buffered I/O library"); |
| 1830 | MODULE_LICENSE("GPL"); |