Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 1 | #include <linux/kernel.h> |
| 2 | #include <linux/module.h> |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 3 | #include <linux/random.h> |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 4 | |
| 5 | #include <linux/blk-mq.h> |
| 6 | #include "blk.h" |
| 7 | #include "blk-mq.h" |
| 8 | #include "blk-mq-tag.h" |
| 9 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 10 | void blk_mq_wait_for_tags(struct blk_mq_tags *tags, struct blk_mq_hw_ctx *hctx, |
| 11 | bool reserved) |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 12 | { |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 13 | int tag, zero = 0; |
| 14 | |
| 15 | tag = blk_mq_get_tag(tags, hctx, &zero, __GFP_WAIT, reserved); |
| 16 | blk_mq_put_tag(tags, tag, &zero); |
| 17 | } |
| 18 | |
| 19 | static bool bt_has_free_tags(struct blk_mq_bitmap_tags *bt) |
| 20 | { |
| 21 | int i; |
| 22 | |
| 23 | for (i = 0; i < bt->map_nr; i++) { |
| 24 | struct blk_mq_bitmap *bm = &bt->map[i]; |
| 25 | int ret; |
| 26 | |
| 27 | ret = find_first_zero_bit(&bm->word, bm->depth); |
| 28 | if (ret < bm->depth) |
| 29 | return true; |
| 30 | } |
| 31 | |
| 32 | return false; |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 33 | } |
| 34 | |
| 35 | bool blk_mq_has_free_tags(struct blk_mq_tags *tags) |
| 36 | { |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 37 | if (!tags) |
| 38 | return true; |
| 39 | |
| 40 | return bt_has_free_tags(&tags->bitmap_tags); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 41 | } |
| 42 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 43 | static int __bt_get_word(struct blk_mq_bitmap *bm, unsigned int last_tag) |
| 44 | { |
| 45 | int tag, org_last_tag, end; |
| 46 | |
Jens Axboe | 59d13bf | 2014-05-09 13:41:15 -0600 | [diff] [blame] | 47 | org_last_tag = last_tag; |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 48 | end = bm->depth; |
| 49 | do { |
| 50 | restart: |
| 51 | tag = find_next_zero_bit(&bm->word, end, last_tag); |
| 52 | if (unlikely(tag >= end)) { |
| 53 | /* |
| 54 | * We started with an offset, start from 0 to |
| 55 | * exhaust the map. |
| 56 | */ |
| 57 | if (org_last_tag && last_tag) { |
| 58 | end = last_tag; |
| 59 | last_tag = 0; |
| 60 | goto restart; |
| 61 | } |
| 62 | return -1; |
| 63 | } |
| 64 | last_tag = tag + 1; |
| 65 | } while (test_and_set_bit_lock(tag, &bm->word)); |
| 66 | |
| 67 | return tag; |
| 68 | } |
| 69 | |
| 70 | /* |
| 71 | * Straight forward bitmap tag implementation, where each bit is a tag |
| 72 | * (cleared == free, and set == busy). The small twist is using per-cpu |
| 73 | * last_tag caches, which blk-mq stores in the blk_mq_ctx software queue |
| 74 | * contexts. This enables us to drastically limit the space searched, |
| 75 | * without dirtying an extra shared cacheline like we would if we stored |
| 76 | * the cache value inside the shared blk_mq_bitmap_tags structure. On top |
| 77 | * of that, each word of tags is in a separate cacheline. This means that |
| 78 | * multiple users will tend to stick to different cachelines, at least |
| 79 | * until the map is exhausted. |
| 80 | */ |
| 81 | static int __bt_get(struct blk_mq_bitmap_tags *bt, unsigned int *tag_cache) |
| 82 | { |
| 83 | unsigned int last_tag, org_last_tag; |
| 84 | int index, i, tag; |
| 85 | |
| 86 | last_tag = org_last_tag = *tag_cache; |
Jens Axboe | 59d13bf | 2014-05-09 13:41:15 -0600 | [diff] [blame] | 87 | index = TAG_TO_INDEX(bt, last_tag); |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 88 | |
| 89 | for (i = 0; i < bt->map_nr; i++) { |
Jens Axboe | 59d13bf | 2014-05-09 13:41:15 -0600 | [diff] [blame] | 90 | tag = __bt_get_word(&bt->map[index], TAG_TO_BIT(bt, last_tag)); |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 91 | if (tag != -1) { |
Jens Axboe | 59d13bf | 2014-05-09 13:41:15 -0600 | [diff] [blame] | 92 | tag += (index << bt->bits_per_word); |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 93 | goto done; |
| 94 | } |
| 95 | |
| 96 | last_tag = 0; |
| 97 | if (++index >= bt->map_nr) |
| 98 | index = 0; |
| 99 | } |
| 100 | |
| 101 | *tag_cache = 0; |
| 102 | return -1; |
| 103 | |
| 104 | /* |
| 105 | * Only update the cache from the allocation path, if we ended |
| 106 | * up using the specific cached tag. |
| 107 | */ |
| 108 | done: |
| 109 | if (tag == org_last_tag) { |
| 110 | last_tag = tag + 1; |
| 111 | if (last_tag >= bt->depth - 1) |
| 112 | last_tag = 0; |
| 113 | |
| 114 | *tag_cache = last_tag; |
| 115 | } |
| 116 | |
| 117 | return tag; |
| 118 | } |
| 119 | |
| 120 | static inline void bt_index_inc(unsigned int *index) |
| 121 | { |
| 122 | *index = (*index + 1) & (BT_WAIT_QUEUES - 1); |
| 123 | } |
| 124 | |
| 125 | static struct bt_wait_state *bt_wait_ptr(struct blk_mq_bitmap_tags *bt, |
| 126 | struct blk_mq_hw_ctx *hctx) |
| 127 | { |
| 128 | struct bt_wait_state *bs; |
| 129 | |
| 130 | if (!hctx) |
| 131 | return &bt->bs[0]; |
| 132 | |
| 133 | bs = &bt->bs[hctx->wait_index]; |
| 134 | bt_index_inc(&hctx->wait_index); |
| 135 | return bs; |
| 136 | } |
| 137 | |
| 138 | static int bt_get(struct blk_mq_bitmap_tags *bt, struct blk_mq_hw_ctx *hctx, |
| 139 | unsigned int *last_tag, gfp_t gfp) |
| 140 | { |
| 141 | struct bt_wait_state *bs; |
| 142 | DEFINE_WAIT(wait); |
| 143 | int tag; |
| 144 | |
| 145 | tag = __bt_get(bt, last_tag); |
| 146 | if (tag != -1) |
| 147 | return tag; |
| 148 | |
| 149 | if (!(gfp & __GFP_WAIT)) |
| 150 | return -1; |
| 151 | |
| 152 | bs = bt_wait_ptr(bt, hctx); |
| 153 | do { |
| 154 | bool was_empty; |
| 155 | |
| 156 | was_empty = list_empty(&wait.task_list); |
| 157 | prepare_to_wait(&bs->wait, &wait, TASK_UNINTERRUPTIBLE); |
| 158 | |
| 159 | tag = __bt_get(bt, last_tag); |
| 160 | if (tag != -1) |
| 161 | break; |
| 162 | |
| 163 | if (was_empty) |
| 164 | atomic_set(&bs->wait_cnt, bt->wake_cnt); |
| 165 | |
| 166 | io_schedule(); |
| 167 | } while (1); |
| 168 | |
| 169 | finish_wait(&bs->wait, &wait); |
| 170 | return tag; |
| 171 | } |
| 172 | |
| 173 | static unsigned int __blk_mq_get_tag(struct blk_mq_tags *tags, |
| 174 | struct blk_mq_hw_ctx *hctx, |
| 175 | unsigned int *last_tag, gfp_t gfp) |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 176 | { |
| 177 | int tag; |
| 178 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 179 | tag = bt_get(&tags->bitmap_tags, hctx, last_tag, gfp); |
| 180 | if (tag >= 0) |
| 181 | return tag + tags->nr_reserved_tags; |
| 182 | |
| 183 | return BLK_MQ_TAG_FAIL; |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 184 | } |
| 185 | |
| 186 | static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_tags *tags, |
| 187 | gfp_t gfp) |
| 188 | { |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 189 | int tag, zero = 0; |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 190 | |
| 191 | if (unlikely(!tags->nr_reserved_tags)) { |
| 192 | WARN_ON_ONCE(1); |
| 193 | return BLK_MQ_TAG_FAIL; |
| 194 | } |
| 195 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 196 | tag = bt_get(&tags->breserved_tags, NULL, &zero, gfp); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 197 | if (tag < 0) |
| 198 | return BLK_MQ_TAG_FAIL; |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 199 | |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 200 | return tag; |
| 201 | } |
| 202 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 203 | unsigned int blk_mq_get_tag(struct blk_mq_tags *tags, |
| 204 | struct blk_mq_hw_ctx *hctx, unsigned int *last_tag, |
| 205 | gfp_t gfp, bool reserved) |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 206 | { |
| 207 | if (!reserved) |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 208 | return __blk_mq_get_tag(tags, hctx, last_tag, gfp); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 209 | |
| 210 | return __blk_mq_get_reserved_tag(tags, gfp); |
| 211 | } |
| 212 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 213 | static struct bt_wait_state *bt_wake_ptr(struct blk_mq_bitmap_tags *bt) |
| 214 | { |
| 215 | int i, wake_index; |
| 216 | |
| 217 | wake_index = bt->wake_index; |
| 218 | for (i = 0; i < BT_WAIT_QUEUES; i++) { |
| 219 | struct bt_wait_state *bs = &bt->bs[wake_index]; |
| 220 | |
| 221 | if (waitqueue_active(&bs->wait)) { |
| 222 | if (wake_index != bt->wake_index) |
| 223 | bt->wake_index = wake_index; |
| 224 | |
| 225 | return bs; |
| 226 | } |
| 227 | |
| 228 | bt_index_inc(&wake_index); |
| 229 | } |
| 230 | |
| 231 | return NULL; |
| 232 | } |
| 233 | |
| 234 | static void bt_clear_tag(struct blk_mq_bitmap_tags *bt, unsigned int tag) |
| 235 | { |
Jens Axboe | 59d13bf | 2014-05-09 13:41:15 -0600 | [diff] [blame] | 236 | const int index = TAG_TO_INDEX(bt, tag); |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 237 | struct bt_wait_state *bs; |
| 238 | |
Ming Lei | 0289b2e | 2014-05-11 01:01:48 +0800 | [diff] [blame] | 239 | /* |
| 240 | * The unlock memory barrier need to order access to req in free |
| 241 | * path and clearing tag bit |
| 242 | */ |
| 243 | clear_bit_unlock(TAG_TO_BIT(bt, tag), &bt->map[index].word); |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 244 | |
| 245 | bs = bt_wake_ptr(bt); |
| 246 | if (bs && atomic_dec_and_test(&bs->wait_cnt)) { |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 247 | atomic_set(&bs->wait_cnt, bt->wake_cnt); |
| 248 | bt_index_inc(&bt->wake_index); |
| 249 | wake_up(&bs->wait); |
| 250 | } |
| 251 | } |
| 252 | |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 253 | static void __blk_mq_put_tag(struct blk_mq_tags *tags, unsigned int tag) |
| 254 | { |
| 255 | BUG_ON(tag >= tags->nr_tags); |
| 256 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 257 | bt_clear_tag(&tags->bitmap_tags, tag); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 258 | } |
| 259 | |
| 260 | static void __blk_mq_put_reserved_tag(struct blk_mq_tags *tags, |
| 261 | unsigned int tag) |
| 262 | { |
| 263 | BUG_ON(tag >= tags->nr_reserved_tags); |
| 264 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 265 | bt_clear_tag(&tags->breserved_tags, tag); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 266 | } |
| 267 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 268 | void blk_mq_put_tag(struct blk_mq_tags *tags, unsigned int tag, |
| 269 | unsigned int *last_tag) |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 270 | { |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 271 | if (tag >= tags->nr_reserved_tags) { |
| 272 | const int real_tag = tag - tags->nr_reserved_tags; |
| 273 | |
| 274 | __blk_mq_put_tag(tags, real_tag); |
| 275 | *last_tag = real_tag; |
| 276 | } else |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 277 | __blk_mq_put_reserved_tag(tags, tag); |
| 278 | } |
| 279 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 280 | static void bt_for_each_free(struct blk_mq_bitmap_tags *bt, |
| 281 | unsigned long *free_map, unsigned int off) |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 282 | { |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 283 | int i; |
| 284 | |
| 285 | for (i = 0; i < bt->map_nr; i++) { |
| 286 | struct blk_mq_bitmap *bm = &bt->map[i]; |
| 287 | int bit = 0; |
| 288 | |
| 289 | do { |
| 290 | bit = find_next_zero_bit(&bm->word, bm->depth, bit); |
| 291 | if (bit >= bm->depth) |
| 292 | break; |
| 293 | |
| 294 | __set_bit(bit + off, free_map); |
| 295 | bit++; |
| 296 | } while (1); |
| 297 | |
Jens Axboe | 59d13bf | 2014-05-09 13:41:15 -0600 | [diff] [blame] | 298 | off += (1 << bt->bits_per_word); |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 299 | } |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 300 | } |
| 301 | |
| 302 | void blk_mq_tag_busy_iter(struct blk_mq_tags *tags, |
| 303 | void (*fn)(void *, unsigned long *), void *data) |
| 304 | { |
| 305 | unsigned long *tag_map; |
| 306 | size_t map_size; |
| 307 | |
| 308 | map_size = ALIGN(tags->nr_tags, BITS_PER_LONG) / BITS_PER_LONG; |
| 309 | tag_map = kzalloc(map_size * sizeof(unsigned long), GFP_ATOMIC); |
| 310 | if (!tag_map) |
| 311 | return; |
| 312 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 313 | bt_for_each_free(&tags->bitmap_tags, tag_map, tags->nr_reserved_tags); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 314 | if (tags->nr_reserved_tags) |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 315 | bt_for_each_free(&tags->breserved_tags, tag_map, 0); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 316 | |
| 317 | fn(data, tag_map); |
| 318 | kfree(tag_map); |
| 319 | } |
| 320 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 321 | static unsigned int bt_unused_tags(struct blk_mq_bitmap_tags *bt) |
| 322 | { |
| 323 | unsigned int i, used; |
| 324 | |
| 325 | for (i = 0, used = 0; i < bt->map_nr; i++) { |
| 326 | struct blk_mq_bitmap *bm = &bt->map[i]; |
| 327 | |
| 328 | used += bitmap_weight(&bm->word, bm->depth); |
| 329 | } |
| 330 | |
| 331 | return bt->depth - used; |
| 332 | } |
| 333 | |
| 334 | static int bt_alloc(struct blk_mq_bitmap_tags *bt, unsigned int depth, |
| 335 | int node, bool reserved) |
| 336 | { |
| 337 | int i; |
| 338 | |
Jens Axboe | 59d13bf | 2014-05-09 13:41:15 -0600 | [diff] [blame] | 339 | bt->bits_per_word = ilog2(BITS_PER_LONG); |
| 340 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 341 | /* |
| 342 | * Depth can be zero for reserved tags, that's not a failure |
| 343 | * condition. |
| 344 | */ |
| 345 | if (depth) { |
Jens Axboe | 59d13bf | 2014-05-09 13:41:15 -0600 | [diff] [blame] | 346 | unsigned int nr, i, map_depth, tags_per_word; |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 347 | |
Jens Axboe | 59d13bf | 2014-05-09 13:41:15 -0600 | [diff] [blame] | 348 | tags_per_word = (1 << bt->bits_per_word); |
| 349 | |
| 350 | /* |
| 351 | * If the tag space is small, shrink the number of tags |
| 352 | * per word so we spread over a few cachelines, at least. |
| 353 | * If less than 4 tags, just forget about it, it's not |
| 354 | * going to work optimally anyway. |
| 355 | */ |
| 356 | if (depth >= 4) { |
| 357 | while (tags_per_word * 4 > depth) { |
| 358 | bt->bits_per_word--; |
| 359 | tags_per_word = (1 << bt->bits_per_word); |
| 360 | } |
| 361 | } |
| 362 | |
| 363 | nr = ALIGN(depth, tags_per_word) / tags_per_word; |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 364 | bt->map = kzalloc_node(nr * sizeof(struct blk_mq_bitmap), |
| 365 | GFP_KERNEL, node); |
| 366 | if (!bt->map) |
| 367 | return -ENOMEM; |
| 368 | |
| 369 | bt->map_nr = nr; |
| 370 | map_depth = depth; |
| 371 | for (i = 0; i < nr; i++) { |
Jens Axboe | 59d13bf | 2014-05-09 13:41:15 -0600 | [diff] [blame] | 372 | bt->map[i].depth = min(map_depth, tags_per_word); |
| 373 | map_depth -= tags_per_word; |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 374 | } |
| 375 | } |
| 376 | |
| 377 | bt->bs = kzalloc(BT_WAIT_QUEUES * sizeof(*bt->bs), GFP_KERNEL); |
| 378 | if (!bt->bs) { |
| 379 | kfree(bt->map); |
| 380 | return -ENOMEM; |
| 381 | } |
| 382 | |
| 383 | for (i = 0; i < BT_WAIT_QUEUES; i++) |
| 384 | init_waitqueue_head(&bt->bs[i].wait); |
| 385 | |
| 386 | bt->wake_cnt = BT_WAIT_BATCH; |
| 387 | if (bt->wake_cnt > depth / 4) |
| 388 | bt->wake_cnt = max(1U, depth / 4); |
| 389 | |
| 390 | bt->depth = depth; |
| 391 | return 0; |
| 392 | } |
| 393 | |
| 394 | static void bt_free(struct blk_mq_bitmap_tags *bt) |
| 395 | { |
| 396 | kfree(bt->map); |
| 397 | kfree(bt->bs); |
| 398 | } |
| 399 | |
| 400 | static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags, |
| 401 | int node) |
| 402 | { |
| 403 | unsigned int depth = tags->nr_tags - tags->nr_reserved_tags; |
| 404 | |
| 405 | if (bt_alloc(&tags->bitmap_tags, depth, node, false)) |
| 406 | goto enomem; |
| 407 | if (bt_alloc(&tags->breserved_tags, tags->nr_reserved_tags, node, true)) |
| 408 | goto enomem; |
| 409 | |
| 410 | return tags; |
| 411 | enomem: |
| 412 | bt_free(&tags->bitmap_tags); |
| 413 | kfree(tags); |
| 414 | return NULL; |
| 415 | } |
| 416 | |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 417 | struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags, |
| 418 | unsigned int reserved_tags, int node) |
| 419 | { |
| 420 | unsigned int nr_tags, nr_cache; |
| 421 | struct blk_mq_tags *tags; |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 422 | |
| 423 | if (total_tags > BLK_MQ_TAG_MAX) { |
| 424 | pr_err("blk-mq: tag depth too large\n"); |
| 425 | return NULL; |
| 426 | } |
| 427 | |
| 428 | tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node); |
| 429 | if (!tags) |
| 430 | return NULL; |
| 431 | |
| 432 | nr_tags = total_tags - reserved_tags; |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 433 | nr_cache = nr_tags / num_online_cpus(); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 434 | |
| 435 | tags->nr_tags = total_tags; |
| 436 | tags->nr_reserved_tags = reserved_tags; |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 437 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 438 | return blk_mq_init_bitmap_tags(tags, node); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 439 | } |
| 440 | |
| 441 | void blk_mq_free_tags(struct blk_mq_tags *tags) |
| 442 | { |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 443 | bt_free(&tags->bitmap_tags); |
| 444 | bt_free(&tags->breserved_tags); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 445 | kfree(tags); |
| 446 | } |
| 447 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 448 | void blk_mq_tag_init_last_tag(struct blk_mq_tags *tags, unsigned int *tag) |
| 449 | { |
| 450 | unsigned int depth = tags->nr_tags - tags->nr_reserved_tags; |
| 451 | |
| 452 | if (depth > 1) |
| 453 | *tag = prandom_u32() % (depth - 1); |
| 454 | else |
| 455 | *tag = 0; |
| 456 | } |
| 457 | |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 458 | ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page) |
| 459 | { |
| 460 | char *orig_page = page; |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 461 | unsigned int free, res; |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 462 | |
| 463 | if (!tags) |
| 464 | return 0; |
| 465 | |
Jens Axboe | 59d13bf | 2014-05-09 13:41:15 -0600 | [diff] [blame] | 466 | page += sprintf(page, "nr_tags=%u, reserved_tags=%u, " |
| 467 | "bits_per_word=%u\n", |
| 468 | tags->nr_tags, tags->nr_reserved_tags, |
| 469 | tags->bitmap_tags.bits_per_word); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 470 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 471 | free = bt_unused_tags(&tags->bitmap_tags); |
| 472 | res = bt_unused_tags(&tags->breserved_tags); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 473 | |
Jens Axboe | 4bb659b | 2014-05-09 09:36:49 -0600 | [diff] [blame] | 474 | page += sprintf(page, "nr_free=%u, nr_reserved=%u\n", free, res); |
Jens Axboe | 320ae51 | 2013-10-24 09:20:05 +0100 | [diff] [blame] | 475 | |
| 476 | return page - orig_page; |
| 477 | } |