| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk> |
| 4 | */ |
| 5 | #include <linux/mm.h> |
| 6 | #include <linux/swap.h> |
| 7 | #include <linux/bio.h> |
| 8 | #include <linux/blkdev.h> |
| 9 | #include <linux/uio.h> |
| 10 | #include <linux/iocontext.h> |
| 11 | #include <linux/slab.h> |
| 12 | #include <linux/init.h> |
| 13 | #include <linux/kernel.h> |
| 14 | #include <linux/export.h> |
| 15 | #include <linux/mempool.h> |
| 16 | #include <linux/workqueue.h> |
| 17 | #include <linux/cgroup.h> |
| 18 | #include <linux/highmem.h> |
| 19 | #include <linux/sched/sysctl.h> |
| 20 | #include <linux/blk-crypto.h> |
| 21 | #include <linux/xarray.h> |
| 22 | |
| 23 | #include <trace/events/block.h> |
| 24 | #include "blk.h" |
| 25 | #include "blk-rq-qos.h" |
| 26 | #include "blk-cgroup.h" |
| 27 | |
| 28 | #define ALLOC_CACHE_THRESHOLD 16 |
| 29 | #define ALLOC_CACHE_MAX 256 |
| 30 | |
| 31 | struct bio_alloc_cache { |
| 32 | struct bio *free_list; |
| 33 | struct bio *free_list_irq; |
| 34 | unsigned int nr; |
| 35 | unsigned int nr_irq; |
| 36 | }; |
| 37 | |
| 38 | static struct biovec_slab { |
| 39 | int nr_vecs; |
| 40 | char *name; |
| 41 | struct kmem_cache *slab; |
| 42 | } bvec_slabs[] __read_mostly = { |
| 43 | { .nr_vecs = 16, .name = "biovec-16" }, |
| 44 | { .nr_vecs = 64, .name = "biovec-64" }, |
| 45 | { .nr_vecs = 128, .name = "biovec-128" }, |
| 46 | { .nr_vecs = BIO_MAX_VECS, .name = "biovec-max" }, |
| 47 | }; |
| 48 | |
| 49 | static struct biovec_slab *biovec_slab(unsigned short nr_vecs) |
| 50 | { |
| 51 | switch (nr_vecs) { |
| 52 | /* smaller bios use inline vecs */ |
| 53 | case 5 ... 16: |
| 54 | return &bvec_slabs[0]; |
| 55 | case 17 ... 64: |
| 56 | return &bvec_slabs[1]; |
| 57 | case 65 ... 128: |
| 58 | return &bvec_slabs[2]; |
| 59 | case 129 ... BIO_MAX_VECS: |
| 60 | return &bvec_slabs[3]; |
| 61 | default: |
| 62 | BUG(); |
| 63 | return NULL; |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | /* |
| 68 | * fs_bio_set is the bio_set containing bio and iovec memory pools used by |
| 69 | * IO code that does not need private memory pools. |
| 70 | */ |
| 71 | struct bio_set fs_bio_set; |
| 72 | EXPORT_SYMBOL(fs_bio_set); |
| 73 | |
| 74 | /* |
| 75 | * Our slab pool management |
| 76 | */ |
| 77 | struct bio_slab { |
| 78 | struct kmem_cache *slab; |
| 79 | unsigned int slab_ref; |
| 80 | unsigned int slab_size; |
| 81 | char name[8]; |
| 82 | }; |
| 83 | static DEFINE_MUTEX(bio_slab_lock); |
| 84 | static DEFINE_XARRAY(bio_slabs); |
| 85 | |
| 86 | static struct bio_slab *create_bio_slab(unsigned int size) |
| 87 | { |
| 88 | struct bio_slab *bslab = kzalloc(sizeof(*bslab), GFP_KERNEL); |
| 89 | |
| 90 | if (!bslab) |
| 91 | return NULL; |
| 92 | |
| 93 | snprintf(bslab->name, sizeof(bslab->name), "bio-%d", size); |
| 94 | bslab->slab = kmem_cache_create(bslab->name, size, |
| 95 | ARCH_KMALLOC_MINALIGN, |
| 96 | SLAB_HWCACHE_ALIGN | SLAB_TYPESAFE_BY_RCU, NULL); |
| 97 | if (!bslab->slab) |
| 98 | goto fail_alloc_slab; |
| 99 | |
| 100 | bslab->slab_ref = 1; |
| 101 | bslab->slab_size = size; |
| 102 | |
| 103 | if (!xa_err(xa_store(&bio_slabs, size, bslab, GFP_KERNEL))) |
| 104 | return bslab; |
| 105 | |
| 106 | kmem_cache_destroy(bslab->slab); |
| 107 | |
| 108 | fail_alloc_slab: |
| 109 | kfree(bslab); |
| 110 | return NULL; |
| 111 | } |
| 112 | |
| 113 | static inline unsigned int bs_bio_slab_size(struct bio_set *bs) |
| 114 | { |
| 115 | return bs->front_pad + sizeof(struct bio) + bs->back_pad; |
| 116 | } |
| 117 | |
| 118 | static struct kmem_cache *bio_find_or_create_slab(struct bio_set *bs) |
| 119 | { |
| 120 | unsigned int size = bs_bio_slab_size(bs); |
| 121 | struct bio_slab *bslab; |
| 122 | |
| 123 | mutex_lock(&bio_slab_lock); |
| 124 | bslab = xa_load(&bio_slabs, size); |
| 125 | if (bslab) |
| 126 | bslab->slab_ref++; |
| 127 | else |
| 128 | bslab = create_bio_slab(size); |
| 129 | mutex_unlock(&bio_slab_lock); |
| 130 | |
| 131 | if (bslab) |
| 132 | return bslab->slab; |
| 133 | return NULL; |
| 134 | } |
| 135 | |
| 136 | static void bio_put_slab(struct bio_set *bs) |
| 137 | { |
| 138 | struct bio_slab *bslab = NULL; |
| 139 | unsigned int slab_size = bs_bio_slab_size(bs); |
| 140 | |
| 141 | mutex_lock(&bio_slab_lock); |
| 142 | |
| 143 | bslab = xa_load(&bio_slabs, slab_size); |
| 144 | if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n")) |
| 145 | goto out; |
| 146 | |
| 147 | WARN_ON_ONCE(bslab->slab != bs->bio_slab); |
| 148 | |
| 149 | WARN_ON(!bslab->slab_ref); |
| 150 | |
| 151 | if (--bslab->slab_ref) |
| 152 | goto out; |
| 153 | |
| 154 | xa_erase(&bio_slabs, slab_size); |
| 155 | |
| 156 | kmem_cache_destroy(bslab->slab); |
| 157 | kfree(bslab); |
| 158 | |
| 159 | out: |
| 160 | mutex_unlock(&bio_slab_lock); |
| 161 | } |
| 162 | |
| 163 | void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned short nr_vecs) |
| 164 | { |
| 165 | BUG_ON(nr_vecs > BIO_MAX_VECS); |
| 166 | |
| 167 | if (nr_vecs == BIO_MAX_VECS) |
| 168 | mempool_free(bv, pool); |
| 169 | else if (nr_vecs > BIO_INLINE_VECS) |
| 170 | kmem_cache_free(biovec_slab(nr_vecs)->slab, bv); |
| 171 | } |
| 172 | |
| 173 | /* |
| 174 | * Make the first allocation restricted and don't dump info on allocation |
| 175 | * failures, since we'll fall back to the mempool in case of failure. |
| 176 | */ |
| 177 | static inline gfp_t bvec_alloc_gfp(gfp_t gfp) |
| 178 | { |
| 179 | return (gfp & ~(__GFP_DIRECT_RECLAIM | __GFP_IO)) | |
| 180 | __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN; |
| 181 | } |
| 182 | |
| 183 | struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs, |
| 184 | gfp_t gfp_mask) |
| 185 | { |
| 186 | struct biovec_slab *bvs = biovec_slab(*nr_vecs); |
| 187 | |
| 188 | if (WARN_ON_ONCE(!bvs)) |
| 189 | return NULL; |
| 190 | |
| 191 | /* |
| 192 | * Upgrade the nr_vecs request to take full advantage of the allocation. |
| 193 | * We also rely on this in the bvec_free path. |
| 194 | */ |
| 195 | *nr_vecs = bvs->nr_vecs; |
| 196 | |
| 197 | /* |
| 198 | * Try a slab allocation first for all smaller allocations. If that |
| 199 | * fails and __GFP_DIRECT_RECLAIM is set retry with the mempool. |
| 200 | * The mempool is sized to handle up to BIO_MAX_VECS entries. |
| 201 | */ |
| 202 | if (*nr_vecs < BIO_MAX_VECS) { |
| 203 | struct bio_vec *bvl; |
| 204 | |
| 205 | bvl = kmem_cache_alloc(bvs->slab, bvec_alloc_gfp(gfp_mask)); |
| 206 | if (likely(bvl) || !(gfp_mask & __GFP_DIRECT_RECLAIM)) |
| 207 | return bvl; |
| 208 | *nr_vecs = BIO_MAX_VECS; |
| 209 | } |
| 210 | |
| 211 | return mempool_alloc(pool, gfp_mask); |
| 212 | } |
| 213 | |
| 214 | void bio_uninit(struct bio *bio) |
| 215 | { |
| 216 | #ifdef CONFIG_BLK_CGROUP |
| 217 | if (bio->bi_blkg) { |
| 218 | blkg_put(bio->bi_blkg); |
| 219 | bio->bi_blkg = NULL; |
| 220 | } |
| 221 | #endif |
| 222 | if (bio_integrity(bio)) |
| 223 | bio_integrity_free(bio); |
| 224 | |
| 225 | bio_crypt_free_ctx(bio); |
| 226 | } |
| 227 | EXPORT_SYMBOL(bio_uninit); |
| 228 | |
| 229 | static void bio_free(struct bio *bio) |
| 230 | { |
| 231 | struct bio_set *bs = bio->bi_pool; |
| 232 | void *p = bio; |
| 233 | |
| 234 | WARN_ON_ONCE(!bs); |
| 235 | |
| 236 | bio_uninit(bio); |
| 237 | bvec_free(&bs->bvec_pool, bio->bi_io_vec, bio->bi_max_vecs); |
| 238 | mempool_free(p - bs->front_pad, &bs->bio_pool); |
| 239 | } |
| 240 | |
| 241 | /* |
| 242 | * Users of this function have their own bio allocation. Subsequently, |
| 243 | * they must remember to pair any call to bio_init() with bio_uninit() |
| 244 | * when IO has completed, or when the bio is released. |
| 245 | */ |
| 246 | void bio_init(struct bio *bio, struct block_device *bdev, struct bio_vec *table, |
| 247 | unsigned short max_vecs, blk_opf_t opf) |
| 248 | { |
| 249 | bio->bi_next = NULL; |
| 250 | bio->bi_bdev = bdev; |
| 251 | bio->bi_opf = opf; |
| 252 | bio->bi_flags = 0; |
| 253 | bio->bi_ioprio = 0; |
| 254 | bio->bi_status = 0; |
| 255 | bio->bi_iter.bi_sector = 0; |
| 256 | bio->bi_iter.bi_size = 0; |
| 257 | bio->bi_iter.bi_idx = 0; |
| 258 | bio->bi_iter.bi_bvec_done = 0; |
| 259 | bio->bi_end_io = NULL; |
| 260 | bio->bi_private = NULL; |
| 261 | #ifdef CONFIG_BLK_CGROUP |
| 262 | bio->bi_blkg = NULL; |
| 263 | bio->bi_issue.value = 0; |
| 264 | if (bdev) |
| 265 | bio_associate_blkg(bio); |
| 266 | #ifdef CONFIG_BLK_CGROUP_IOCOST |
| 267 | bio->bi_iocost_cost = 0; |
| 268 | #endif |
| 269 | #endif |
| 270 | #ifdef CONFIG_BLK_INLINE_ENCRYPTION |
| 271 | bio->bi_crypt_context = NULL; |
| 272 | #endif |
| 273 | #ifdef CONFIG_BLK_DEV_INTEGRITY |
| 274 | bio->bi_integrity = NULL; |
| 275 | #endif |
| 276 | bio->bi_vcnt = 0; |
| 277 | |
| 278 | atomic_set(&bio->__bi_remaining, 1); |
| 279 | atomic_set(&bio->__bi_cnt, 1); |
| 280 | bio->bi_cookie = BLK_QC_T_NONE; |
| 281 | |
| 282 | bio->bi_max_vecs = max_vecs; |
| 283 | bio->bi_io_vec = table; |
| 284 | bio->bi_pool = NULL; |
| 285 | } |
| 286 | EXPORT_SYMBOL(bio_init); |
| 287 | |
| 288 | /** |
| 289 | * bio_reset - reinitialize a bio |
| 290 | * @bio: bio to reset |
| 291 | * @bdev: block device to use the bio for |
| 292 | * @opf: operation and flags for bio |
| 293 | * |
| 294 | * Description: |
| 295 | * After calling bio_reset(), @bio will be in the same state as a freshly |
| 296 | * allocated bio returned bio bio_alloc_bioset() - the only fields that are |
| 297 | * preserved are the ones that are initialized by bio_alloc_bioset(). See |
| 298 | * comment in struct bio. |
| 299 | */ |
| 300 | void bio_reset(struct bio *bio, struct block_device *bdev, blk_opf_t opf) |
| 301 | { |
| 302 | bio_uninit(bio); |
| 303 | memset(bio, 0, BIO_RESET_BYTES); |
| 304 | atomic_set(&bio->__bi_remaining, 1); |
| 305 | bio->bi_bdev = bdev; |
| 306 | if (bio->bi_bdev) |
| 307 | bio_associate_blkg(bio); |
| 308 | bio->bi_opf = opf; |
| 309 | } |
| 310 | EXPORT_SYMBOL(bio_reset); |
| 311 | |
| 312 | static struct bio *__bio_chain_endio(struct bio *bio) |
| 313 | { |
| 314 | struct bio *parent = bio->bi_private; |
| 315 | |
| 316 | if (bio->bi_status && !parent->bi_status) |
| 317 | parent->bi_status = bio->bi_status; |
| 318 | bio_put(bio); |
| 319 | return parent; |
| 320 | } |
| 321 | |
| 322 | static void bio_chain_endio(struct bio *bio) |
| 323 | { |
| 324 | bio_endio(__bio_chain_endio(bio)); |
| 325 | } |
| 326 | |
| 327 | /** |
| 328 | * bio_chain - chain bio completions |
| 329 | * @bio: the target bio |
| 330 | * @parent: the parent bio of @bio |
| 331 | * |
| 332 | * The caller won't have a bi_end_io called when @bio completes - instead, |
| 333 | * @parent's bi_end_io won't be called until both @parent and @bio have |
| 334 | * completed; the chained bio will also be freed when it completes. |
| 335 | * |
| 336 | * The caller must not set bi_private or bi_end_io in @bio. |
| 337 | */ |
| 338 | void bio_chain(struct bio *bio, struct bio *parent) |
| 339 | { |
| 340 | BUG_ON(bio->bi_private || bio->bi_end_io); |
| 341 | |
| 342 | bio->bi_private = parent; |
| 343 | bio->bi_end_io = bio_chain_endio; |
| 344 | bio_inc_remaining(parent); |
| 345 | } |
| 346 | EXPORT_SYMBOL(bio_chain); |
| 347 | |
| 348 | struct bio *blk_next_bio(struct bio *bio, struct block_device *bdev, |
| 349 | unsigned int nr_pages, blk_opf_t opf, gfp_t gfp) |
| 350 | { |
| 351 | struct bio *new = bio_alloc(bdev, nr_pages, opf, gfp); |
| 352 | |
| 353 | if (bio) { |
| 354 | bio_chain(bio, new); |
| 355 | submit_bio(bio); |
| 356 | } |
| 357 | |
| 358 | return new; |
| 359 | } |
| 360 | EXPORT_SYMBOL_GPL(blk_next_bio); |
| 361 | |
| 362 | static void bio_alloc_rescue(struct work_struct *work) |
| 363 | { |
| 364 | struct bio_set *bs = container_of(work, struct bio_set, rescue_work); |
| 365 | struct bio *bio; |
| 366 | |
| 367 | while (1) { |
| 368 | spin_lock(&bs->rescue_lock); |
| 369 | bio = bio_list_pop(&bs->rescue_list); |
| 370 | spin_unlock(&bs->rescue_lock); |
| 371 | |
| 372 | if (!bio) |
| 373 | break; |
| 374 | |
| 375 | submit_bio_noacct(bio); |
| 376 | } |
| 377 | } |
| 378 | |
| 379 | static void punt_bios_to_rescuer(struct bio_set *bs) |
| 380 | { |
| 381 | struct bio_list punt, nopunt; |
| 382 | struct bio *bio; |
| 383 | |
| 384 | if (WARN_ON_ONCE(!bs->rescue_workqueue)) |
| 385 | return; |
| 386 | /* |
| 387 | * In order to guarantee forward progress we must punt only bios that |
| 388 | * were allocated from this bio_set; otherwise, if there was a bio on |
| 389 | * there for a stacking driver higher up in the stack, processing it |
| 390 | * could require allocating bios from this bio_set, and doing that from |
| 391 | * our own rescuer would be bad. |
| 392 | * |
| 393 | * Since bio lists are singly linked, pop them all instead of trying to |
| 394 | * remove from the middle of the list: |
| 395 | */ |
| 396 | |
| 397 | bio_list_init(&punt); |
| 398 | bio_list_init(&nopunt); |
| 399 | |
| 400 | while ((bio = bio_list_pop(¤t->bio_list[0]))) |
| 401 | bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio); |
| 402 | current->bio_list[0] = nopunt; |
| 403 | |
| 404 | bio_list_init(&nopunt); |
| 405 | while ((bio = bio_list_pop(¤t->bio_list[1]))) |
| 406 | bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio); |
| 407 | current->bio_list[1] = nopunt; |
| 408 | |
| 409 | spin_lock(&bs->rescue_lock); |
| 410 | bio_list_merge(&bs->rescue_list, &punt); |
| 411 | spin_unlock(&bs->rescue_lock); |
| 412 | |
| 413 | queue_work(bs->rescue_workqueue, &bs->rescue_work); |
| 414 | } |
| 415 | |
| 416 | static void bio_alloc_irq_cache_splice(struct bio_alloc_cache *cache) |
| 417 | { |
| 418 | unsigned long flags; |
| 419 | |
| 420 | /* cache->free_list must be empty */ |
| 421 | if (WARN_ON_ONCE(cache->free_list)) |
| 422 | return; |
| 423 | |
| 424 | local_irq_save(flags); |
| 425 | cache->free_list = cache->free_list_irq; |
| 426 | cache->free_list_irq = NULL; |
| 427 | cache->nr += cache->nr_irq; |
| 428 | cache->nr_irq = 0; |
| 429 | local_irq_restore(flags); |
| 430 | } |
| 431 | |
| 432 | static struct bio *bio_alloc_percpu_cache(struct block_device *bdev, |
| 433 | unsigned short nr_vecs, blk_opf_t opf, gfp_t gfp, |
| 434 | struct bio_set *bs) |
| 435 | { |
| 436 | struct bio_alloc_cache *cache; |
| 437 | struct bio *bio; |
| 438 | |
| 439 | cache = per_cpu_ptr(bs->cache, get_cpu()); |
| 440 | if (!cache->free_list) { |
| 441 | if (READ_ONCE(cache->nr_irq) >= ALLOC_CACHE_THRESHOLD) |
| 442 | bio_alloc_irq_cache_splice(cache); |
| 443 | if (!cache->free_list) { |
| 444 | put_cpu(); |
| 445 | return NULL; |
| 446 | } |
| 447 | } |
| 448 | bio = cache->free_list; |
| 449 | cache->free_list = bio->bi_next; |
| 450 | cache->nr--; |
| 451 | put_cpu(); |
| 452 | |
| 453 | bio_init(bio, bdev, nr_vecs ? bio->bi_inline_vecs : NULL, nr_vecs, opf); |
| 454 | bio->bi_pool = bs; |
| 455 | return bio; |
| 456 | } |
| 457 | |
| 458 | /** |
| 459 | * bio_alloc_bioset - allocate a bio for I/O |
| 460 | * @bdev: block device to allocate the bio for (can be %NULL) |
| 461 | * @nr_vecs: number of bvecs to pre-allocate |
| 462 | * @opf: operation and flags for bio |
| 463 | * @gfp_mask: the GFP_* mask given to the slab allocator |
| 464 | * @bs: the bio_set to allocate from. |
| 465 | * |
| 466 | * Allocate a bio from the mempools in @bs. |
| 467 | * |
| 468 | * If %__GFP_DIRECT_RECLAIM is set then bio_alloc will always be able to |
| 469 | * allocate a bio. This is due to the mempool guarantees. To make this work, |
| 470 | * callers must never allocate more than 1 bio at a time from the general pool. |
| 471 | * Callers that need to allocate more than 1 bio must always submit the |
| 472 | * previously allocated bio for IO before attempting to allocate a new one. |
| 473 | * Failure to do so can cause deadlocks under memory pressure. |
| 474 | * |
| 475 | * Note that when running under submit_bio_noacct() (i.e. any block driver), |
| 476 | * bios are not submitted until after you return - see the code in |
| 477 | * submit_bio_noacct() that converts recursion into iteration, to prevent |
| 478 | * stack overflows. |
| 479 | * |
| 480 | * This would normally mean allocating multiple bios under submit_bio_noacct() |
| 481 | * would be susceptible to deadlocks, but we have |
| 482 | * deadlock avoidance code that resubmits any blocked bios from a rescuer |
| 483 | * thread. |
| 484 | * |
| 485 | * However, we do not guarantee forward progress for allocations from other |
| 486 | * mempools. Doing multiple allocations from the same mempool under |
| 487 | * submit_bio_noacct() should be avoided - instead, use bio_set's front_pad |
| 488 | * for per bio allocations. |
| 489 | * |
| 490 | * Returns: Pointer to new bio on success, NULL on failure. |
| 491 | */ |
| 492 | struct bio *bio_alloc_bioset(struct block_device *bdev, unsigned short nr_vecs, |
| 493 | blk_opf_t opf, gfp_t gfp_mask, |
| 494 | struct bio_set *bs) |
| 495 | { |
| 496 | gfp_t saved_gfp = gfp_mask; |
| 497 | struct bio *bio; |
| 498 | void *p; |
| 499 | |
| 500 | /* should not use nobvec bioset for nr_vecs > 0 */ |
| 501 | if (WARN_ON_ONCE(!mempool_initialized(&bs->bvec_pool) && nr_vecs > 0)) |
| 502 | return NULL; |
| 503 | |
| 504 | if (opf & REQ_ALLOC_CACHE) { |
| 505 | if (bs->cache && nr_vecs <= BIO_INLINE_VECS) { |
| 506 | bio = bio_alloc_percpu_cache(bdev, nr_vecs, opf, |
| 507 | gfp_mask, bs); |
| 508 | if (bio) |
| 509 | return bio; |
| 510 | /* |
| 511 | * No cached bio available, bio returned below marked with |
| 512 | * REQ_ALLOC_CACHE to particpate in per-cpu alloc cache. |
| 513 | */ |
| 514 | } else { |
| 515 | opf &= ~REQ_ALLOC_CACHE; |
| 516 | } |
| 517 | } |
| 518 | |
| 519 | /* |
| 520 | * submit_bio_noacct() converts recursion to iteration; this means if |
| 521 | * we're running beneath it, any bios we allocate and submit will not be |
| 522 | * submitted (and thus freed) until after we return. |
| 523 | * |
| 524 | * This exposes us to a potential deadlock if we allocate multiple bios |
| 525 | * from the same bio_set() while running underneath submit_bio_noacct(). |
| 526 | * If we were to allocate multiple bios (say a stacking block driver |
| 527 | * that was splitting bios), we would deadlock if we exhausted the |
| 528 | * mempool's reserve. |
| 529 | * |
| 530 | * We solve this, and guarantee forward progress, with a rescuer |
| 531 | * workqueue per bio_set. If we go to allocate and there are bios on |
| 532 | * current->bio_list, we first try the allocation without |
| 533 | * __GFP_DIRECT_RECLAIM; if that fails, we punt those bios we would be |
| 534 | * blocking to the rescuer workqueue before we retry with the original |
| 535 | * gfp_flags. |
| 536 | */ |
| 537 | if (current->bio_list && |
| 538 | (!bio_list_empty(¤t->bio_list[0]) || |
| 539 | !bio_list_empty(¤t->bio_list[1])) && |
| 540 | bs->rescue_workqueue) |
| 541 | gfp_mask &= ~__GFP_DIRECT_RECLAIM; |
| 542 | |
| 543 | p = mempool_alloc(&bs->bio_pool, gfp_mask); |
| 544 | if (!p && gfp_mask != saved_gfp) { |
| 545 | punt_bios_to_rescuer(bs); |
| 546 | gfp_mask = saved_gfp; |
| 547 | p = mempool_alloc(&bs->bio_pool, gfp_mask); |
| 548 | } |
| 549 | if (unlikely(!p)) |
| 550 | return NULL; |
| 551 | if (!mempool_is_saturated(&bs->bio_pool)) |
| 552 | opf &= ~REQ_ALLOC_CACHE; |
| 553 | |
| 554 | bio = p + bs->front_pad; |
| 555 | if (nr_vecs > BIO_INLINE_VECS) { |
| 556 | struct bio_vec *bvl = NULL; |
| 557 | |
| 558 | bvl = bvec_alloc(&bs->bvec_pool, &nr_vecs, gfp_mask); |
| 559 | if (!bvl && gfp_mask != saved_gfp) { |
| 560 | punt_bios_to_rescuer(bs); |
| 561 | gfp_mask = saved_gfp; |
| 562 | bvl = bvec_alloc(&bs->bvec_pool, &nr_vecs, gfp_mask); |
| 563 | } |
| 564 | if (unlikely(!bvl)) |
| 565 | goto err_free; |
| 566 | |
| 567 | bio_init(bio, bdev, bvl, nr_vecs, opf); |
| 568 | } else if (nr_vecs) { |
| 569 | bio_init(bio, bdev, bio->bi_inline_vecs, BIO_INLINE_VECS, opf); |
| 570 | } else { |
| 571 | bio_init(bio, bdev, NULL, 0, opf); |
| 572 | } |
| 573 | |
| 574 | bio->bi_pool = bs; |
| 575 | return bio; |
| 576 | |
| 577 | err_free: |
| 578 | mempool_free(p, &bs->bio_pool); |
| 579 | return NULL; |
| 580 | } |
| 581 | EXPORT_SYMBOL(bio_alloc_bioset); |
| 582 | |
| 583 | /** |
| 584 | * bio_kmalloc - kmalloc a bio |
| 585 | * @nr_vecs: number of bio_vecs to allocate |
| 586 | * @gfp_mask: the GFP_* mask given to the slab allocator |
| 587 | * |
| 588 | * Use kmalloc to allocate a bio (including bvecs). The bio must be initialized |
| 589 | * using bio_init() before use. To free a bio returned from this function use |
| 590 | * kfree() after calling bio_uninit(). A bio returned from this function can |
| 591 | * be reused by calling bio_uninit() before calling bio_init() again. |
| 592 | * |
| 593 | * Note that unlike bio_alloc() or bio_alloc_bioset() allocations from this |
| 594 | * function are not backed by a mempool can fail. Do not use this function |
| 595 | * for allocations in the file system I/O path. |
| 596 | * |
| 597 | * Returns: Pointer to new bio on success, NULL on failure. |
| 598 | */ |
| 599 | struct bio *bio_kmalloc(unsigned short nr_vecs, gfp_t gfp_mask) |
| 600 | { |
| 601 | struct bio *bio; |
| 602 | |
| 603 | if (nr_vecs > UIO_MAXIOV) |
| 604 | return NULL; |
| 605 | return kmalloc(struct_size(bio, bi_inline_vecs, nr_vecs), gfp_mask); |
| 606 | } |
| 607 | EXPORT_SYMBOL(bio_kmalloc); |
| 608 | |
| 609 | void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start) |
| 610 | { |
| 611 | struct bio_vec bv; |
| 612 | struct bvec_iter iter; |
| 613 | |
| 614 | __bio_for_each_segment(bv, bio, iter, start) |
| 615 | memzero_bvec(&bv); |
| 616 | } |
| 617 | EXPORT_SYMBOL(zero_fill_bio_iter); |
| 618 | |
| 619 | /** |
| 620 | * bio_truncate - truncate the bio to small size of @new_size |
| 621 | * @bio: the bio to be truncated |
| 622 | * @new_size: new size for truncating the bio |
| 623 | * |
| 624 | * Description: |
| 625 | * Truncate the bio to new size of @new_size. If bio_op(bio) is |
| 626 | * REQ_OP_READ, zero the truncated part. This function should only |
| 627 | * be used for handling corner cases, such as bio eod. |
| 628 | */ |
| 629 | static void bio_truncate(struct bio *bio, unsigned new_size) |
| 630 | { |
| 631 | struct bio_vec bv; |
| 632 | struct bvec_iter iter; |
| 633 | unsigned int done = 0; |
| 634 | bool truncated = false; |
| 635 | |
| 636 | if (new_size >= bio->bi_iter.bi_size) |
| 637 | return; |
| 638 | |
| 639 | if (bio_op(bio) != REQ_OP_READ) |
| 640 | goto exit; |
| 641 | |
| 642 | bio_for_each_segment(bv, bio, iter) { |
| 643 | if (done + bv.bv_len > new_size) { |
| 644 | unsigned offset; |
| 645 | |
| 646 | if (!truncated) |
| 647 | offset = new_size - done; |
| 648 | else |
| 649 | offset = 0; |
| 650 | zero_user(bv.bv_page, bv.bv_offset + offset, |
| 651 | bv.bv_len - offset); |
| 652 | truncated = true; |
| 653 | } |
| 654 | done += bv.bv_len; |
| 655 | } |
| 656 | |
| 657 | exit: |
| 658 | /* |
| 659 | * Don't touch bvec table here and make it really immutable, since |
| 660 | * fs bio user has to retrieve all pages via bio_for_each_segment_all |
| 661 | * in its .end_bio() callback. |
| 662 | * |
| 663 | * It is enough to truncate bio by updating .bi_size since we can make |
| 664 | * correct bvec with the updated .bi_size for drivers. |
| 665 | */ |
| 666 | bio->bi_iter.bi_size = new_size; |
| 667 | } |
| 668 | |
| 669 | /** |
| 670 | * guard_bio_eod - truncate a BIO to fit the block device |
| 671 | * @bio: bio to truncate |
| 672 | * |
| 673 | * This allows us to do IO even on the odd last sectors of a device, even if the |
| 674 | * block size is some multiple of the physical sector size. |
| 675 | * |
| 676 | * We'll just truncate the bio to the size of the device, and clear the end of |
| 677 | * the buffer head manually. Truly out-of-range accesses will turn into actual |
| 678 | * I/O errors, this only handles the "we need to be able to do I/O at the final |
| 679 | * sector" case. |
| 680 | */ |
| 681 | void guard_bio_eod(struct bio *bio) |
| 682 | { |
| 683 | sector_t maxsector = bdev_nr_sectors(bio->bi_bdev); |
| 684 | |
| 685 | if (!maxsector) |
| 686 | return; |
| 687 | |
| 688 | /* |
| 689 | * If the *whole* IO is past the end of the device, |
| 690 | * let it through, and the IO layer will turn it into |
| 691 | * an EIO. |
| 692 | */ |
| 693 | if (unlikely(bio->bi_iter.bi_sector >= maxsector)) |
| 694 | return; |
| 695 | |
| 696 | maxsector -= bio->bi_iter.bi_sector; |
| 697 | if (likely((bio->bi_iter.bi_size >> 9) <= maxsector)) |
| 698 | return; |
| 699 | |
| 700 | bio_truncate(bio, maxsector << 9); |
| 701 | } |
| 702 | |
| 703 | static int __bio_alloc_cache_prune(struct bio_alloc_cache *cache, |
| 704 | unsigned int nr) |
| 705 | { |
| 706 | unsigned int i = 0; |
| 707 | struct bio *bio; |
| 708 | |
| 709 | while ((bio = cache->free_list) != NULL) { |
| 710 | cache->free_list = bio->bi_next; |
| 711 | cache->nr--; |
| 712 | bio_free(bio); |
| 713 | if (++i == nr) |
| 714 | break; |
| 715 | } |
| 716 | return i; |
| 717 | } |
| 718 | |
| 719 | static void bio_alloc_cache_prune(struct bio_alloc_cache *cache, |
| 720 | unsigned int nr) |
| 721 | { |
| 722 | nr -= __bio_alloc_cache_prune(cache, nr); |
| 723 | if (!READ_ONCE(cache->free_list)) { |
| 724 | bio_alloc_irq_cache_splice(cache); |
| 725 | __bio_alloc_cache_prune(cache, nr); |
| 726 | } |
| 727 | } |
| 728 | |
| 729 | static int bio_cpu_dead(unsigned int cpu, struct hlist_node *node) |
| 730 | { |
| 731 | struct bio_set *bs; |
| 732 | |
| 733 | bs = hlist_entry_safe(node, struct bio_set, cpuhp_dead); |
| 734 | if (bs->cache) { |
| 735 | struct bio_alloc_cache *cache = per_cpu_ptr(bs->cache, cpu); |
| 736 | |
| 737 | bio_alloc_cache_prune(cache, -1U); |
| 738 | } |
| 739 | return 0; |
| 740 | } |
| 741 | |
| 742 | static void bio_alloc_cache_destroy(struct bio_set *bs) |
| 743 | { |
| 744 | int cpu; |
| 745 | |
| 746 | if (!bs->cache) |
| 747 | return; |
| 748 | |
| 749 | cpuhp_state_remove_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead); |
| 750 | for_each_possible_cpu(cpu) { |
| 751 | struct bio_alloc_cache *cache; |
| 752 | |
| 753 | cache = per_cpu_ptr(bs->cache, cpu); |
| 754 | bio_alloc_cache_prune(cache, -1U); |
| 755 | } |
| 756 | free_percpu(bs->cache); |
| 757 | bs->cache = NULL; |
| 758 | } |
| 759 | |
| 760 | static inline void bio_put_percpu_cache(struct bio *bio) |
| 761 | { |
| 762 | struct bio_alloc_cache *cache; |
| 763 | |
| 764 | cache = per_cpu_ptr(bio->bi_pool->cache, get_cpu()); |
| 765 | if (READ_ONCE(cache->nr_irq) + cache->nr > ALLOC_CACHE_MAX) { |
| 766 | put_cpu(); |
| 767 | bio_free(bio); |
| 768 | return; |
| 769 | } |
| 770 | |
| 771 | bio_uninit(bio); |
| 772 | |
| 773 | if ((bio->bi_opf & REQ_POLLED) && !WARN_ON_ONCE(in_interrupt())) { |
| 774 | bio->bi_next = cache->free_list; |
| 775 | bio->bi_bdev = NULL; |
| 776 | cache->free_list = bio; |
| 777 | cache->nr++; |
| 778 | } else { |
| 779 | unsigned long flags; |
| 780 | |
| 781 | local_irq_save(flags); |
| 782 | bio->bi_next = cache->free_list_irq; |
| 783 | cache->free_list_irq = bio; |
| 784 | cache->nr_irq++; |
| 785 | local_irq_restore(flags); |
| 786 | } |
| 787 | put_cpu(); |
| 788 | } |
| 789 | |
| 790 | /** |
| 791 | * bio_put - release a reference to a bio |
| 792 | * @bio: bio to release reference to |
| 793 | * |
| 794 | * Description: |
| 795 | * Put a reference to a &struct bio, either one you have gotten with |
| 796 | * bio_alloc, bio_get or bio_clone_*. The last put of a bio will free it. |
| 797 | **/ |
| 798 | void bio_put(struct bio *bio) |
| 799 | { |
| 800 | if (unlikely(bio_flagged(bio, BIO_REFFED))) { |
| 801 | BUG_ON(!atomic_read(&bio->__bi_cnt)); |
| 802 | if (!atomic_dec_and_test(&bio->__bi_cnt)) |
| 803 | return; |
| 804 | } |
| 805 | if (bio->bi_opf & REQ_ALLOC_CACHE) |
| 806 | bio_put_percpu_cache(bio); |
| 807 | else |
| 808 | bio_free(bio); |
| 809 | } |
| 810 | EXPORT_SYMBOL(bio_put); |
| 811 | |
| 812 | static int __bio_clone(struct bio *bio, struct bio *bio_src, gfp_t gfp) |
| 813 | { |
| 814 | bio_set_flag(bio, BIO_CLONED); |
| 815 | bio->bi_ioprio = bio_src->bi_ioprio; |
| 816 | bio->bi_iter = bio_src->bi_iter; |
| 817 | |
| 818 | if (bio->bi_bdev) { |
| 819 | if (bio->bi_bdev == bio_src->bi_bdev && |
| 820 | bio_flagged(bio_src, BIO_REMAPPED)) |
| 821 | bio_set_flag(bio, BIO_REMAPPED); |
| 822 | bio_clone_blkg_association(bio, bio_src); |
| 823 | } |
| 824 | |
| 825 | if (bio_crypt_clone(bio, bio_src, gfp) < 0) |
| 826 | return -ENOMEM; |
| 827 | if (bio_integrity(bio_src) && |
| 828 | bio_integrity_clone(bio, bio_src, gfp) < 0) |
| 829 | return -ENOMEM; |
| 830 | return 0; |
| 831 | } |
| 832 | |
| 833 | /** |
| 834 | * bio_alloc_clone - clone a bio that shares the original bio's biovec |
| 835 | * @bdev: block_device to clone onto |
| 836 | * @bio_src: bio to clone from |
| 837 | * @gfp: allocation priority |
| 838 | * @bs: bio_set to allocate from |
| 839 | * |
| 840 | * Allocate a new bio that is a clone of @bio_src. The caller owns the returned |
| 841 | * bio, but not the actual data it points to. |
| 842 | * |
| 843 | * The caller must ensure that the return bio is not freed before @bio_src. |
| 844 | */ |
| 845 | struct bio *bio_alloc_clone(struct block_device *bdev, struct bio *bio_src, |
| 846 | gfp_t gfp, struct bio_set *bs) |
| 847 | { |
| 848 | struct bio *bio; |
| 849 | |
| 850 | bio = bio_alloc_bioset(bdev, 0, bio_src->bi_opf, gfp, bs); |
| 851 | if (!bio) |
| 852 | return NULL; |
| 853 | |
| 854 | if (__bio_clone(bio, bio_src, gfp) < 0) { |
| 855 | bio_put(bio); |
| 856 | return NULL; |
| 857 | } |
| 858 | bio->bi_io_vec = bio_src->bi_io_vec; |
| 859 | |
| 860 | return bio; |
| 861 | } |
| 862 | EXPORT_SYMBOL(bio_alloc_clone); |
| 863 | |
| 864 | /** |
| 865 | * bio_init_clone - clone a bio that shares the original bio's biovec |
| 866 | * @bdev: block_device to clone onto |
| 867 | * @bio: bio to clone into |
| 868 | * @bio_src: bio to clone from |
| 869 | * @gfp: allocation priority |
| 870 | * |
| 871 | * Initialize a new bio in caller provided memory that is a clone of @bio_src. |
| 872 | * The caller owns the returned bio, but not the actual data it points to. |
| 873 | * |
| 874 | * The caller must ensure that @bio_src is not freed before @bio. |
| 875 | */ |
| 876 | int bio_init_clone(struct block_device *bdev, struct bio *bio, |
| 877 | struct bio *bio_src, gfp_t gfp) |
| 878 | { |
| 879 | int ret; |
| 880 | |
| 881 | bio_init(bio, bdev, bio_src->bi_io_vec, 0, bio_src->bi_opf); |
| 882 | ret = __bio_clone(bio, bio_src, gfp); |
| 883 | if (ret) |
| 884 | bio_uninit(bio); |
| 885 | return ret; |
| 886 | } |
| 887 | EXPORT_SYMBOL(bio_init_clone); |
| 888 | |
| 889 | /** |
| 890 | * bio_full - check if the bio is full |
| 891 | * @bio: bio to check |
| 892 | * @len: length of one segment to be added |
| 893 | * |
| 894 | * Return true if @bio is full and one segment with @len bytes can't be |
| 895 | * added to the bio, otherwise return false |
| 896 | */ |
| 897 | static inline bool bio_full(struct bio *bio, unsigned len) |
| 898 | { |
| 899 | if (bio->bi_vcnt >= bio->bi_max_vecs) |
| 900 | return true; |
| 901 | if (bio->bi_iter.bi_size > UINT_MAX - len) |
| 902 | return true; |
| 903 | return false; |
| 904 | } |
| 905 | |
| 906 | static bool bvec_try_merge_page(struct bio_vec *bv, struct page *page, |
| 907 | unsigned int len, unsigned int off, bool *same_page) |
| 908 | { |
| 909 | size_t bv_end = bv->bv_offset + bv->bv_len; |
| 910 | phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) + bv_end - 1; |
| 911 | phys_addr_t page_addr = page_to_phys(page); |
| 912 | |
| 913 | if (vec_end_addr + 1 != page_addr + off) |
| 914 | return false; |
| 915 | if (xen_domain() && !xen_biovec_phys_mergeable(bv, page)) |
| 916 | return false; |
| 917 | if (!zone_device_pages_have_same_pgmap(bv->bv_page, page)) |
| 918 | return false; |
| 919 | |
| 920 | *same_page = ((vec_end_addr & PAGE_MASK) == page_addr); |
| 921 | if (!*same_page) { |
| 922 | if (IS_ENABLED(CONFIG_KMSAN)) |
| 923 | return false; |
| 924 | if (bv->bv_page + bv_end / PAGE_SIZE != page + off / PAGE_SIZE) |
| 925 | return false; |
| 926 | } |
| 927 | |
| 928 | bv->bv_len += len; |
| 929 | return true; |
| 930 | } |
| 931 | |
| 932 | /* |
| 933 | * Try to merge a page into a segment, while obeying the hardware segment |
| 934 | * size limit. This is not for normal read/write bios, but for passthrough |
| 935 | * or Zone Append operations that we can't split. |
| 936 | */ |
| 937 | bool bvec_try_merge_hw_page(struct request_queue *q, struct bio_vec *bv, |
| 938 | struct page *page, unsigned len, unsigned offset, |
| 939 | bool *same_page) |
| 940 | { |
| 941 | unsigned long mask = queue_segment_boundary(q); |
| 942 | phys_addr_t addr1 = page_to_phys(bv->bv_page) + bv->bv_offset; |
| 943 | phys_addr_t addr2 = page_to_phys(page) + offset + len - 1; |
| 944 | |
| 945 | if ((addr1 | mask) != (addr2 | mask)) |
| 946 | return false; |
| 947 | if (len > queue_max_segment_size(q) - bv->bv_len) |
| 948 | return false; |
| 949 | return bvec_try_merge_page(bv, page, len, offset, same_page); |
| 950 | } |
| 951 | |
| 952 | /** |
| 953 | * bio_add_hw_page - attempt to add a page to a bio with hw constraints |
| 954 | * @q: the target queue |
| 955 | * @bio: destination bio |
| 956 | * @page: page to add |
| 957 | * @len: vec entry length |
| 958 | * @offset: vec entry offset |
| 959 | * @max_sectors: maximum number of sectors that can be added |
| 960 | * @same_page: return if the segment has been merged inside the same page |
| 961 | * |
| 962 | * Add a page to a bio while respecting the hardware max_sectors, max_segment |
| 963 | * and gap limitations. |
| 964 | */ |
| 965 | int bio_add_hw_page(struct request_queue *q, struct bio *bio, |
| 966 | struct page *page, unsigned int len, unsigned int offset, |
| 967 | unsigned int max_sectors, bool *same_page) |
| 968 | { |
| 969 | unsigned int max_size = max_sectors << SECTOR_SHIFT; |
| 970 | |
| 971 | if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) |
| 972 | return 0; |
| 973 | |
| 974 | len = min3(len, max_size, queue_max_segment_size(q)); |
| 975 | if (len > max_size - bio->bi_iter.bi_size) |
| 976 | return 0; |
| 977 | |
| 978 | if (bio->bi_vcnt > 0) { |
| 979 | struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; |
| 980 | |
| 981 | if (bvec_try_merge_hw_page(q, bv, page, len, offset, |
| 982 | same_page)) { |
| 983 | bio->bi_iter.bi_size += len; |
| 984 | return len; |
| 985 | } |
| 986 | |
| 987 | if (bio->bi_vcnt >= |
| 988 | min(bio->bi_max_vecs, queue_max_segments(q))) |
| 989 | return 0; |
| 990 | |
| 991 | /* |
| 992 | * If the queue doesn't support SG gaps and adding this segment |
| 993 | * would create a gap, disallow it. |
| 994 | */ |
| 995 | if (bvec_gap_to_prev(&q->limits, bv, offset)) |
| 996 | return 0; |
| 997 | } |
| 998 | |
| 999 | bvec_set_page(&bio->bi_io_vec[bio->bi_vcnt], page, len, offset); |
| 1000 | bio->bi_vcnt++; |
| 1001 | bio->bi_iter.bi_size += len; |
| 1002 | return len; |
| 1003 | } |
| 1004 | |
| 1005 | /** |
| 1006 | * bio_add_pc_page - attempt to add page to passthrough bio |
| 1007 | * @q: the target queue |
| 1008 | * @bio: destination bio |
| 1009 | * @page: page to add |
| 1010 | * @len: vec entry length |
| 1011 | * @offset: vec entry offset |
| 1012 | * |
| 1013 | * Attempt to add a page to the bio_vec maplist. This can fail for a |
| 1014 | * number of reasons, such as the bio being full or target block device |
| 1015 | * limitations. The target block device must allow bio's up to PAGE_SIZE, |
| 1016 | * so it is always possible to add a single page to an empty bio. |
| 1017 | * |
| 1018 | * This should only be used by passthrough bios. |
| 1019 | */ |
| 1020 | int bio_add_pc_page(struct request_queue *q, struct bio *bio, |
| 1021 | struct page *page, unsigned int len, unsigned int offset) |
| 1022 | { |
| 1023 | bool same_page = false; |
| 1024 | return bio_add_hw_page(q, bio, page, len, offset, |
| 1025 | queue_max_hw_sectors(q), &same_page); |
| 1026 | } |
| 1027 | EXPORT_SYMBOL(bio_add_pc_page); |
| 1028 | |
| 1029 | /** |
| 1030 | * bio_add_zone_append_page - attempt to add page to zone-append bio |
| 1031 | * @bio: destination bio |
| 1032 | * @page: page to add |
| 1033 | * @len: vec entry length |
| 1034 | * @offset: vec entry offset |
| 1035 | * |
| 1036 | * Attempt to add a page to the bio_vec maplist of a bio that will be submitted |
| 1037 | * for a zone-append request. This can fail for a number of reasons, such as the |
| 1038 | * bio being full or the target block device is not a zoned block device or |
| 1039 | * other limitations of the target block device. The target block device must |
| 1040 | * allow bio's up to PAGE_SIZE, so it is always possible to add a single page |
| 1041 | * to an empty bio. |
| 1042 | * |
| 1043 | * Returns: number of bytes added to the bio, or 0 in case of a failure. |
| 1044 | */ |
| 1045 | int bio_add_zone_append_page(struct bio *bio, struct page *page, |
| 1046 | unsigned int len, unsigned int offset) |
| 1047 | { |
| 1048 | struct request_queue *q = bdev_get_queue(bio->bi_bdev); |
| 1049 | bool same_page = false; |
| 1050 | |
| 1051 | if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_ZONE_APPEND)) |
| 1052 | return 0; |
| 1053 | |
| 1054 | if (WARN_ON_ONCE(!bdev_is_zoned(bio->bi_bdev))) |
| 1055 | return 0; |
| 1056 | |
| 1057 | return bio_add_hw_page(q, bio, page, len, offset, |
| 1058 | queue_max_zone_append_sectors(q), &same_page); |
| 1059 | } |
| 1060 | EXPORT_SYMBOL_GPL(bio_add_zone_append_page); |
| 1061 | |
| 1062 | /** |
| 1063 | * __bio_add_page - add page(s) to a bio in a new segment |
| 1064 | * @bio: destination bio |
| 1065 | * @page: start page to add |
| 1066 | * @len: length of the data to add, may cross pages |
| 1067 | * @off: offset of the data relative to @page, may cross pages |
| 1068 | * |
| 1069 | * Add the data at @page + @off to @bio as a new bvec. The caller must ensure |
| 1070 | * that @bio has space for another bvec. |
| 1071 | */ |
| 1072 | void __bio_add_page(struct bio *bio, struct page *page, |
| 1073 | unsigned int len, unsigned int off) |
| 1074 | { |
| 1075 | WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)); |
| 1076 | WARN_ON_ONCE(bio_full(bio, len)); |
| 1077 | |
| 1078 | bvec_set_page(&bio->bi_io_vec[bio->bi_vcnt], page, len, off); |
| 1079 | bio->bi_iter.bi_size += len; |
| 1080 | bio->bi_vcnt++; |
| 1081 | } |
| 1082 | EXPORT_SYMBOL_GPL(__bio_add_page); |
| 1083 | |
| 1084 | /** |
| 1085 | * bio_add_page - attempt to add page(s) to bio |
| 1086 | * @bio: destination bio |
| 1087 | * @page: start page to add |
| 1088 | * @len: vec entry length, may cross pages |
| 1089 | * @offset: vec entry offset relative to @page, may cross pages |
| 1090 | * |
| 1091 | * Attempt to add page(s) to the bio_vec maplist. This will only fail |
| 1092 | * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio. |
| 1093 | */ |
| 1094 | int bio_add_page(struct bio *bio, struct page *page, |
| 1095 | unsigned int len, unsigned int offset) |
| 1096 | { |
| 1097 | bool same_page = false; |
| 1098 | |
| 1099 | if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) |
| 1100 | return 0; |
| 1101 | if (bio->bi_iter.bi_size > UINT_MAX - len) |
| 1102 | return 0; |
| 1103 | |
| 1104 | if (bio->bi_vcnt > 0 && |
| 1105 | bvec_try_merge_page(&bio->bi_io_vec[bio->bi_vcnt - 1], |
| 1106 | page, len, offset, &same_page)) { |
| 1107 | bio->bi_iter.bi_size += len; |
| 1108 | return len; |
| 1109 | } |
| 1110 | |
| 1111 | if (bio->bi_vcnt >= bio->bi_max_vecs) |
| 1112 | return 0; |
| 1113 | __bio_add_page(bio, page, len, offset); |
| 1114 | return len; |
| 1115 | } |
| 1116 | EXPORT_SYMBOL(bio_add_page); |
| 1117 | |
| 1118 | void bio_add_folio_nofail(struct bio *bio, struct folio *folio, size_t len, |
| 1119 | size_t off) |
| 1120 | { |
| 1121 | WARN_ON_ONCE(len > UINT_MAX); |
| 1122 | WARN_ON_ONCE(off > UINT_MAX); |
| 1123 | __bio_add_page(bio, &folio->page, len, off); |
| 1124 | } |
| 1125 | |
| 1126 | /** |
| 1127 | * bio_add_folio - Attempt to add part of a folio to a bio. |
| 1128 | * @bio: BIO to add to. |
| 1129 | * @folio: Folio to add. |
| 1130 | * @len: How many bytes from the folio to add. |
| 1131 | * @off: First byte in this folio to add. |
| 1132 | * |
| 1133 | * Filesystems that use folios can call this function instead of calling |
| 1134 | * bio_add_page() for each page in the folio. If @off is bigger than |
| 1135 | * PAGE_SIZE, this function can create a bio_vec that starts in a page |
| 1136 | * after the bv_page. BIOs do not support folios that are 4GiB or larger. |
| 1137 | * |
| 1138 | * Return: Whether the addition was successful. |
| 1139 | */ |
| 1140 | bool bio_add_folio(struct bio *bio, struct folio *folio, size_t len, |
| 1141 | size_t off) |
| 1142 | { |
| 1143 | if (len > UINT_MAX || off > UINT_MAX) |
| 1144 | return false; |
| 1145 | return bio_add_page(bio, &folio->page, len, off) > 0; |
| 1146 | } |
| 1147 | EXPORT_SYMBOL(bio_add_folio); |
| 1148 | |
| 1149 | void __bio_release_pages(struct bio *bio, bool mark_dirty) |
| 1150 | { |
| 1151 | struct folio_iter fi; |
| 1152 | |
| 1153 | bio_for_each_folio_all(fi, bio) { |
| 1154 | struct page *page; |
| 1155 | size_t done = 0; |
| 1156 | |
| 1157 | if (mark_dirty) { |
| 1158 | folio_lock(fi.folio); |
| 1159 | folio_mark_dirty(fi.folio); |
| 1160 | folio_unlock(fi.folio); |
| 1161 | } |
| 1162 | page = folio_page(fi.folio, fi.offset / PAGE_SIZE); |
| 1163 | do { |
| 1164 | bio_release_page(bio, page++); |
| 1165 | done += PAGE_SIZE; |
| 1166 | } while (done < fi.length); |
| 1167 | } |
| 1168 | } |
| 1169 | EXPORT_SYMBOL_GPL(__bio_release_pages); |
| 1170 | |
| 1171 | void bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter) |
| 1172 | { |
| 1173 | size_t size = iov_iter_count(iter); |
| 1174 | |
| 1175 | WARN_ON_ONCE(bio->bi_max_vecs); |
| 1176 | |
| 1177 | if (bio_op(bio) == REQ_OP_ZONE_APPEND) { |
| 1178 | struct request_queue *q = bdev_get_queue(bio->bi_bdev); |
| 1179 | size_t max_sectors = queue_max_zone_append_sectors(q); |
| 1180 | |
| 1181 | size = min(size, max_sectors << SECTOR_SHIFT); |
| 1182 | } |
| 1183 | |
| 1184 | bio->bi_vcnt = iter->nr_segs; |
| 1185 | bio->bi_io_vec = (struct bio_vec *)iter->bvec; |
| 1186 | bio->bi_iter.bi_bvec_done = iter->iov_offset; |
| 1187 | bio->bi_iter.bi_size = size; |
| 1188 | bio_set_flag(bio, BIO_CLONED); |
| 1189 | } |
| 1190 | |
| 1191 | static int bio_iov_add_page(struct bio *bio, struct page *page, |
| 1192 | unsigned int len, unsigned int offset) |
| 1193 | { |
| 1194 | bool same_page = false; |
| 1195 | |
| 1196 | if (WARN_ON_ONCE(bio->bi_iter.bi_size > UINT_MAX - len)) |
| 1197 | return -EIO; |
| 1198 | |
| 1199 | if (bio->bi_vcnt > 0 && |
| 1200 | bvec_try_merge_page(&bio->bi_io_vec[bio->bi_vcnt - 1], |
| 1201 | page, len, offset, &same_page)) { |
| 1202 | bio->bi_iter.bi_size += len; |
| 1203 | if (same_page) |
| 1204 | bio_release_page(bio, page); |
| 1205 | return 0; |
| 1206 | } |
| 1207 | __bio_add_page(bio, page, len, offset); |
| 1208 | return 0; |
| 1209 | } |
| 1210 | |
| 1211 | static int bio_iov_add_zone_append_page(struct bio *bio, struct page *page, |
| 1212 | unsigned int len, unsigned int offset) |
| 1213 | { |
| 1214 | struct request_queue *q = bdev_get_queue(bio->bi_bdev); |
| 1215 | bool same_page = false; |
| 1216 | |
| 1217 | if (bio_add_hw_page(q, bio, page, len, offset, |
| 1218 | queue_max_zone_append_sectors(q), &same_page) != len) |
| 1219 | return -EINVAL; |
| 1220 | if (same_page) |
| 1221 | bio_release_page(bio, page); |
| 1222 | return 0; |
| 1223 | } |
| 1224 | |
| 1225 | #define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *)) |
| 1226 | |
| 1227 | /** |
| 1228 | * __bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio |
| 1229 | * @bio: bio to add pages to |
| 1230 | * @iter: iov iterator describing the region to be mapped |
| 1231 | * |
| 1232 | * Extracts pages from *iter and appends them to @bio's bvec array. The pages |
| 1233 | * will have to be cleaned up in the way indicated by the BIO_PAGE_PINNED flag. |
| 1234 | * For a multi-segment *iter, this function only adds pages from the next |
| 1235 | * non-empty segment of the iov iterator. |
| 1236 | */ |
| 1237 | static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) |
| 1238 | { |
| 1239 | iov_iter_extraction_t extraction_flags = 0; |
| 1240 | unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt; |
| 1241 | unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt; |
| 1242 | struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt; |
| 1243 | struct page **pages = (struct page **)bv; |
| 1244 | ssize_t size, left; |
| 1245 | unsigned len, i = 0; |
| 1246 | size_t offset; |
| 1247 | int ret = 0; |
| 1248 | |
| 1249 | /* |
| 1250 | * Move page array up in the allocated memory for the bio vecs as far as |
| 1251 | * possible so that we can start filling biovecs from the beginning |
| 1252 | * without overwriting the temporary page array. |
| 1253 | */ |
| 1254 | BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2); |
| 1255 | pages += entries_left * (PAGE_PTRS_PER_BVEC - 1); |
| 1256 | |
| 1257 | if (bio->bi_bdev && blk_queue_pci_p2pdma(bio->bi_bdev->bd_disk->queue)) |
| 1258 | extraction_flags |= ITER_ALLOW_P2PDMA; |
| 1259 | |
| 1260 | /* |
| 1261 | * Each segment in the iov is required to be a block size multiple. |
| 1262 | * However, we may not be able to get the entire segment if it spans |
| 1263 | * more pages than bi_max_vecs allows, so we have to ALIGN_DOWN the |
| 1264 | * result to ensure the bio's total size is correct. The remainder of |
| 1265 | * the iov data will be picked up in the next bio iteration. |
| 1266 | */ |
| 1267 | size = iov_iter_extract_pages(iter, &pages, |
| 1268 | UINT_MAX - bio->bi_iter.bi_size, |
| 1269 | nr_pages, extraction_flags, &offset); |
| 1270 | if (unlikely(size <= 0)) |
| 1271 | return size ? size : -EFAULT; |
| 1272 | |
| 1273 | nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE); |
| 1274 | |
| 1275 | if (bio->bi_bdev) { |
| 1276 | size_t trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1); |
| 1277 | iov_iter_revert(iter, trim); |
| 1278 | size -= trim; |
| 1279 | } |
| 1280 | |
| 1281 | if (unlikely(!size)) { |
| 1282 | ret = -EFAULT; |
| 1283 | goto out; |
| 1284 | } |
| 1285 | |
| 1286 | for (left = size, i = 0; left > 0; left -= len, i++) { |
| 1287 | struct page *page = pages[i]; |
| 1288 | |
| 1289 | len = min_t(size_t, PAGE_SIZE - offset, left); |
| 1290 | if (bio_op(bio) == REQ_OP_ZONE_APPEND) { |
| 1291 | ret = bio_iov_add_zone_append_page(bio, page, len, |
| 1292 | offset); |
| 1293 | if (ret) |
| 1294 | break; |
| 1295 | } else |
| 1296 | bio_iov_add_page(bio, page, len, offset); |
| 1297 | |
| 1298 | offset = 0; |
| 1299 | } |
| 1300 | |
| 1301 | iov_iter_revert(iter, left); |
| 1302 | out: |
| 1303 | while (i < nr_pages) |
| 1304 | bio_release_page(bio, pages[i++]); |
| 1305 | |
| 1306 | return ret; |
| 1307 | } |
| 1308 | |
| 1309 | /** |
| 1310 | * bio_iov_iter_get_pages - add user or kernel pages to a bio |
| 1311 | * @bio: bio to add pages to |
| 1312 | * @iter: iov iterator describing the region to be added |
| 1313 | * |
| 1314 | * This takes either an iterator pointing to user memory, or one pointing to |
| 1315 | * kernel pages (BVEC iterator). If we're adding user pages, we pin them and |
| 1316 | * map them into the kernel. On IO completion, the caller should put those |
| 1317 | * pages. For bvec based iterators bio_iov_iter_get_pages() uses the provided |
| 1318 | * bvecs rather than copying them. Hence anyone issuing kiocb based IO needs |
| 1319 | * to ensure the bvecs and pages stay referenced until the submitted I/O is |
| 1320 | * completed by a call to ->ki_complete() or returns with an error other than |
| 1321 | * -EIOCBQUEUED. The caller needs to check if the bio is flagged BIO_NO_PAGE_REF |
| 1322 | * on IO completion. If it isn't, then pages should be released. |
| 1323 | * |
| 1324 | * The function tries, but does not guarantee, to pin as many pages as |
| 1325 | * fit into the bio, or are requested in @iter, whatever is smaller. If |
| 1326 | * MM encounters an error pinning the requested pages, it stops. Error |
| 1327 | * is returned only if 0 pages could be pinned. |
| 1328 | */ |
| 1329 | int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) |
| 1330 | { |
| 1331 | int ret = 0; |
| 1332 | |
| 1333 | if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) |
| 1334 | return -EIO; |
| 1335 | |
| 1336 | if (iov_iter_is_bvec(iter)) { |
| 1337 | bio_iov_bvec_set(bio, iter); |
| 1338 | iov_iter_advance(iter, bio->bi_iter.bi_size); |
| 1339 | return 0; |
| 1340 | } |
| 1341 | |
| 1342 | if (iov_iter_extract_will_pin(iter)) |
| 1343 | bio_set_flag(bio, BIO_PAGE_PINNED); |
| 1344 | do { |
| 1345 | ret = __bio_iov_iter_get_pages(bio, iter); |
| 1346 | } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0)); |
| 1347 | |
| 1348 | return bio->bi_vcnt ? 0 : ret; |
| 1349 | } |
| 1350 | EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages); |
| 1351 | |
| 1352 | static void submit_bio_wait_endio(struct bio *bio) |
| 1353 | { |
| 1354 | complete(bio->bi_private); |
| 1355 | } |
| 1356 | |
| 1357 | /** |
| 1358 | * submit_bio_wait - submit a bio, and wait until it completes |
| 1359 | * @bio: The &struct bio which describes the I/O |
| 1360 | * |
| 1361 | * Simple wrapper around submit_bio(). Returns 0 on success, or the error from |
| 1362 | * bio_endio() on failure. |
| 1363 | * |
| 1364 | * WARNING: Unlike to how submit_bio() is usually used, this function does not |
| 1365 | * result in bio reference to be consumed. The caller must drop the reference |
| 1366 | * on his own. |
| 1367 | */ |
| 1368 | int submit_bio_wait(struct bio *bio) |
| 1369 | { |
| 1370 | DECLARE_COMPLETION_ONSTACK_MAP(done, |
| 1371 | bio->bi_bdev->bd_disk->lockdep_map); |
| 1372 | unsigned long hang_check; |
| 1373 | |
| 1374 | bio->bi_private = &done; |
| 1375 | bio->bi_end_io = submit_bio_wait_endio; |
| 1376 | bio->bi_opf |= REQ_SYNC; |
| 1377 | submit_bio(bio); |
| 1378 | |
| 1379 | /* Prevent hang_check timer from firing at us during very long I/O */ |
| 1380 | hang_check = sysctl_hung_task_timeout_secs; |
| 1381 | if (hang_check) |
| 1382 | while (!wait_for_completion_io_timeout(&done, |
| 1383 | hang_check * (HZ/2))) |
| 1384 | ; |
| 1385 | else |
| 1386 | wait_for_completion_io(&done); |
| 1387 | |
| 1388 | return blk_status_to_errno(bio->bi_status); |
| 1389 | } |
| 1390 | EXPORT_SYMBOL(submit_bio_wait); |
| 1391 | |
| 1392 | void __bio_advance(struct bio *bio, unsigned bytes) |
| 1393 | { |
| 1394 | if (bio_integrity(bio)) |
| 1395 | bio_integrity_advance(bio, bytes); |
| 1396 | |
| 1397 | bio_crypt_advance(bio, bytes); |
| 1398 | bio_advance_iter(bio, &bio->bi_iter, bytes); |
| 1399 | } |
| 1400 | EXPORT_SYMBOL(__bio_advance); |
| 1401 | |
| 1402 | void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter, |
| 1403 | struct bio *src, struct bvec_iter *src_iter) |
| 1404 | { |
| 1405 | while (src_iter->bi_size && dst_iter->bi_size) { |
| 1406 | struct bio_vec src_bv = bio_iter_iovec(src, *src_iter); |
| 1407 | struct bio_vec dst_bv = bio_iter_iovec(dst, *dst_iter); |
| 1408 | unsigned int bytes = min(src_bv.bv_len, dst_bv.bv_len); |
| 1409 | void *src_buf = bvec_kmap_local(&src_bv); |
| 1410 | void *dst_buf = bvec_kmap_local(&dst_bv); |
| 1411 | |
| 1412 | memcpy(dst_buf, src_buf, bytes); |
| 1413 | |
| 1414 | kunmap_local(dst_buf); |
| 1415 | kunmap_local(src_buf); |
| 1416 | |
| 1417 | bio_advance_iter_single(src, src_iter, bytes); |
| 1418 | bio_advance_iter_single(dst, dst_iter, bytes); |
| 1419 | } |
| 1420 | } |
| 1421 | EXPORT_SYMBOL(bio_copy_data_iter); |
| 1422 | |
| 1423 | /** |
| 1424 | * bio_copy_data - copy contents of data buffers from one bio to another |
| 1425 | * @src: source bio |
| 1426 | * @dst: destination bio |
| 1427 | * |
| 1428 | * Stops when it reaches the end of either @src or @dst - that is, copies |
| 1429 | * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios). |
| 1430 | */ |
| 1431 | void bio_copy_data(struct bio *dst, struct bio *src) |
| 1432 | { |
| 1433 | struct bvec_iter src_iter = src->bi_iter; |
| 1434 | struct bvec_iter dst_iter = dst->bi_iter; |
| 1435 | |
| 1436 | bio_copy_data_iter(dst, &dst_iter, src, &src_iter); |
| 1437 | } |
| 1438 | EXPORT_SYMBOL(bio_copy_data); |
| 1439 | |
| 1440 | void bio_free_pages(struct bio *bio) |
| 1441 | { |
| 1442 | struct bio_vec *bvec; |
| 1443 | struct bvec_iter_all iter_all; |
| 1444 | |
| 1445 | bio_for_each_segment_all(bvec, bio, iter_all) |
| 1446 | __free_page(bvec->bv_page); |
| 1447 | } |
| 1448 | EXPORT_SYMBOL(bio_free_pages); |
| 1449 | |
| 1450 | /* |
| 1451 | * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions |
| 1452 | * for performing direct-IO in BIOs. |
| 1453 | * |
| 1454 | * The problem is that we cannot run folio_mark_dirty() from interrupt context |
| 1455 | * because the required locks are not interrupt-safe. So what we can do is to |
| 1456 | * mark the pages dirty _before_ performing IO. And in interrupt context, |
| 1457 | * check that the pages are still dirty. If so, fine. If not, redirty them |
| 1458 | * in process context. |
| 1459 | * |
| 1460 | * Note that this code is very hard to test under normal circumstances because |
| 1461 | * direct-io pins the pages with get_user_pages(). This makes |
| 1462 | * is_page_cache_freeable return false, and the VM will not clean the pages. |
| 1463 | * But other code (eg, flusher threads) could clean the pages if they are mapped |
| 1464 | * pagecache. |
| 1465 | * |
| 1466 | * Simply disabling the call to bio_set_pages_dirty() is a good way to test the |
| 1467 | * deferred bio dirtying paths. |
| 1468 | */ |
| 1469 | |
| 1470 | /* |
| 1471 | * bio_set_pages_dirty() will mark all the bio's pages as dirty. |
| 1472 | */ |
| 1473 | void bio_set_pages_dirty(struct bio *bio) |
| 1474 | { |
| 1475 | struct folio_iter fi; |
| 1476 | |
| 1477 | bio_for_each_folio_all(fi, bio) { |
| 1478 | folio_lock(fi.folio); |
| 1479 | folio_mark_dirty(fi.folio); |
| 1480 | folio_unlock(fi.folio); |
| 1481 | } |
| 1482 | } |
| 1483 | EXPORT_SYMBOL_GPL(bio_set_pages_dirty); |
| 1484 | |
| 1485 | /* |
| 1486 | * bio_check_pages_dirty() will check that all the BIO's pages are still dirty. |
| 1487 | * If they are, then fine. If, however, some pages are clean then they must |
| 1488 | * have been written out during the direct-IO read. So we take another ref on |
| 1489 | * the BIO and re-dirty the pages in process context. |
| 1490 | * |
| 1491 | * It is expected that bio_check_pages_dirty() will wholly own the BIO from |
| 1492 | * here on. It will unpin each page and will run one bio_put() against the |
| 1493 | * BIO. |
| 1494 | */ |
| 1495 | |
| 1496 | static void bio_dirty_fn(struct work_struct *work); |
| 1497 | |
| 1498 | static DECLARE_WORK(bio_dirty_work, bio_dirty_fn); |
| 1499 | static DEFINE_SPINLOCK(bio_dirty_lock); |
| 1500 | static struct bio *bio_dirty_list; |
| 1501 | |
| 1502 | /* |
| 1503 | * This runs in process context |
| 1504 | */ |
| 1505 | static void bio_dirty_fn(struct work_struct *work) |
| 1506 | { |
| 1507 | struct bio *bio, *next; |
| 1508 | |
| 1509 | spin_lock_irq(&bio_dirty_lock); |
| 1510 | next = bio_dirty_list; |
| 1511 | bio_dirty_list = NULL; |
| 1512 | spin_unlock_irq(&bio_dirty_lock); |
| 1513 | |
| 1514 | while ((bio = next) != NULL) { |
| 1515 | next = bio->bi_private; |
| 1516 | |
| 1517 | bio_release_pages(bio, true); |
| 1518 | bio_put(bio); |
| 1519 | } |
| 1520 | } |
| 1521 | |
| 1522 | void bio_check_pages_dirty(struct bio *bio) |
| 1523 | { |
| 1524 | struct folio_iter fi; |
| 1525 | unsigned long flags; |
| 1526 | |
| 1527 | bio_for_each_folio_all(fi, bio) { |
| 1528 | if (!folio_test_dirty(fi.folio)) |
| 1529 | goto defer; |
| 1530 | } |
| 1531 | |
| 1532 | bio_release_pages(bio, false); |
| 1533 | bio_put(bio); |
| 1534 | return; |
| 1535 | defer: |
| 1536 | spin_lock_irqsave(&bio_dirty_lock, flags); |
| 1537 | bio->bi_private = bio_dirty_list; |
| 1538 | bio_dirty_list = bio; |
| 1539 | spin_unlock_irqrestore(&bio_dirty_lock, flags); |
| 1540 | schedule_work(&bio_dirty_work); |
| 1541 | } |
| 1542 | EXPORT_SYMBOL_GPL(bio_check_pages_dirty); |
| 1543 | |
| 1544 | static inline bool bio_remaining_done(struct bio *bio) |
| 1545 | { |
| 1546 | /* |
| 1547 | * If we're not chaining, then ->__bi_remaining is always 1 and |
| 1548 | * we always end io on the first invocation. |
| 1549 | */ |
| 1550 | if (!bio_flagged(bio, BIO_CHAIN)) |
| 1551 | return true; |
| 1552 | |
| 1553 | BUG_ON(atomic_read(&bio->__bi_remaining) <= 0); |
| 1554 | |
| 1555 | if (atomic_dec_and_test(&bio->__bi_remaining)) { |
| 1556 | bio_clear_flag(bio, BIO_CHAIN); |
| 1557 | return true; |
| 1558 | } |
| 1559 | |
| 1560 | return false; |
| 1561 | } |
| 1562 | |
| 1563 | /** |
| 1564 | * bio_endio - end I/O on a bio |
| 1565 | * @bio: bio |
| 1566 | * |
| 1567 | * Description: |
| 1568 | * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred |
| 1569 | * way to end I/O on a bio. No one should call bi_end_io() directly on a |
| 1570 | * bio unless they own it and thus know that it has an end_io function. |
| 1571 | * |
| 1572 | * bio_endio() can be called several times on a bio that has been chained |
| 1573 | * using bio_chain(). The ->bi_end_io() function will only be called the |
| 1574 | * last time. |
| 1575 | **/ |
| 1576 | void bio_endio(struct bio *bio) |
| 1577 | { |
| 1578 | again: |
| 1579 | if (!bio_remaining_done(bio)) |
| 1580 | return; |
| 1581 | if (!bio_integrity_endio(bio)) |
| 1582 | return; |
| 1583 | |
| 1584 | rq_qos_done_bio(bio); |
| 1585 | |
| 1586 | if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) { |
| 1587 | trace_block_bio_complete(bdev_get_queue(bio->bi_bdev), bio); |
| 1588 | bio_clear_flag(bio, BIO_TRACE_COMPLETION); |
| 1589 | } |
| 1590 | |
| 1591 | /* |
| 1592 | * Need to have a real endio function for chained bios, otherwise |
| 1593 | * various corner cases will break (like stacking block devices that |
| 1594 | * save/restore bi_end_io) - however, we want to avoid unbounded |
| 1595 | * recursion and blowing the stack. Tail call optimization would |
| 1596 | * handle this, but compiling with frame pointers also disables |
| 1597 | * gcc's sibling call optimization. |
| 1598 | */ |
| 1599 | if (bio->bi_end_io == bio_chain_endio) { |
| 1600 | bio = __bio_chain_endio(bio); |
| 1601 | goto again; |
| 1602 | } |
| 1603 | |
| 1604 | blk_throtl_bio_endio(bio); |
| 1605 | /* release cgroup info */ |
| 1606 | bio_uninit(bio); |
| 1607 | if (bio->bi_end_io) |
| 1608 | bio->bi_end_io(bio); |
| 1609 | } |
| 1610 | EXPORT_SYMBOL(bio_endio); |
| 1611 | |
| 1612 | /** |
| 1613 | * bio_split - split a bio |
| 1614 | * @bio: bio to split |
| 1615 | * @sectors: number of sectors to split from the front of @bio |
| 1616 | * @gfp: gfp mask |
| 1617 | * @bs: bio set to allocate from |
| 1618 | * |
| 1619 | * Allocates and returns a new bio which represents @sectors from the start of |
| 1620 | * @bio, and updates @bio to represent the remaining sectors. |
| 1621 | * |
| 1622 | * Unless this is a discard request the newly allocated bio will point |
| 1623 | * to @bio's bi_io_vec. It is the caller's responsibility to ensure that |
| 1624 | * neither @bio nor @bs are freed before the split bio. |
| 1625 | */ |
| 1626 | struct bio *bio_split(struct bio *bio, int sectors, |
| 1627 | gfp_t gfp, struct bio_set *bs) |
| 1628 | { |
| 1629 | struct bio *split; |
| 1630 | |
| 1631 | BUG_ON(sectors <= 0); |
| 1632 | BUG_ON(sectors >= bio_sectors(bio)); |
| 1633 | |
| 1634 | /* Zone append commands cannot be split */ |
| 1635 | if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND)) |
| 1636 | return NULL; |
| 1637 | |
| 1638 | split = bio_alloc_clone(bio->bi_bdev, bio, gfp, bs); |
| 1639 | if (!split) |
| 1640 | return NULL; |
| 1641 | |
| 1642 | split->bi_iter.bi_size = sectors << 9; |
| 1643 | |
| 1644 | if (bio_integrity(split)) |
| 1645 | bio_integrity_trim(split); |
| 1646 | |
| 1647 | bio_advance(bio, split->bi_iter.bi_size); |
| 1648 | |
| 1649 | if (bio_flagged(bio, BIO_TRACE_COMPLETION)) |
| 1650 | bio_set_flag(split, BIO_TRACE_COMPLETION); |
| 1651 | |
| 1652 | return split; |
| 1653 | } |
| 1654 | EXPORT_SYMBOL(bio_split); |
| 1655 | |
| 1656 | /** |
| 1657 | * bio_trim - trim a bio |
| 1658 | * @bio: bio to trim |
| 1659 | * @offset: number of sectors to trim from the front of @bio |
| 1660 | * @size: size we want to trim @bio to, in sectors |
| 1661 | * |
| 1662 | * This function is typically used for bios that are cloned and submitted |
| 1663 | * to the underlying device in parts. |
| 1664 | */ |
| 1665 | void bio_trim(struct bio *bio, sector_t offset, sector_t size) |
| 1666 | { |
| 1667 | if (WARN_ON_ONCE(offset > BIO_MAX_SECTORS || size > BIO_MAX_SECTORS || |
| 1668 | offset + size > bio_sectors(bio))) |
| 1669 | return; |
| 1670 | |
| 1671 | size <<= 9; |
| 1672 | if (offset == 0 && size == bio->bi_iter.bi_size) |
| 1673 | return; |
| 1674 | |
| 1675 | bio_advance(bio, offset << 9); |
| 1676 | bio->bi_iter.bi_size = size; |
| 1677 | |
| 1678 | if (bio_integrity(bio)) |
| 1679 | bio_integrity_trim(bio); |
| 1680 | } |
| 1681 | EXPORT_SYMBOL_GPL(bio_trim); |
| 1682 | |
| 1683 | /* |
| 1684 | * create memory pools for biovec's in a bio_set. |
| 1685 | * use the global biovec slabs created for general use. |
| 1686 | */ |
| 1687 | int biovec_init_pool(mempool_t *pool, int pool_entries) |
| 1688 | { |
| 1689 | struct biovec_slab *bp = bvec_slabs + ARRAY_SIZE(bvec_slabs) - 1; |
| 1690 | |
| 1691 | return mempool_init_slab_pool(pool, pool_entries, bp->slab); |
| 1692 | } |
| 1693 | |
| 1694 | /* |
| 1695 | * bioset_exit - exit a bioset initialized with bioset_init() |
| 1696 | * |
| 1697 | * May be called on a zeroed but uninitialized bioset (i.e. allocated with |
| 1698 | * kzalloc()). |
| 1699 | */ |
| 1700 | void bioset_exit(struct bio_set *bs) |
| 1701 | { |
| 1702 | bio_alloc_cache_destroy(bs); |
| 1703 | if (bs->rescue_workqueue) |
| 1704 | destroy_workqueue(bs->rescue_workqueue); |
| 1705 | bs->rescue_workqueue = NULL; |
| 1706 | |
| 1707 | mempool_exit(&bs->bio_pool); |
| 1708 | mempool_exit(&bs->bvec_pool); |
| 1709 | |
| 1710 | bioset_integrity_free(bs); |
| 1711 | if (bs->bio_slab) |
| 1712 | bio_put_slab(bs); |
| 1713 | bs->bio_slab = NULL; |
| 1714 | } |
| 1715 | EXPORT_SYMBOL(bioset_exit); |
| 1716 | |
| 1717 | /** |
| 1718 | * bioset_init - Initialize a bio_set |
| 1719 | * @bs: pool to initialize |
| 1720 | * @pool_size: Number of bio and bio_vecs to cache in the mempool |
| 1721 | * @front_pad: Number of bytes to allocate in front of the returned bio |
| 1722 | * @flags: Flags to modify behavior, currently %BIOSET_NEED_BVECS |
| 1723 | * and %BIOSET_NEED_RESCUER |
| 1724 | * |
| 1725 | * Description: |
| 1726 | * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller |
| 1727 | * to ask for a number of bytes to be allocated in front of the bio. |
| 1728 | * Front pad allocation is useful for embedding the bio inside |
| 1729 | * another structure, to avoid allocating extra data to go with the bio. |
| 1730 | * Note that the bio must be embedded at the END of that structure always, |
| 1731 | * or things will break badly. |
| 1732 | * If %BIOSET_NEED_BVECS is set in @flags, a separate pool will be allocated |
| 1733 | * for allocating iovecs. This pool is not needed e.g. for bio_init_clone(). |
| 1734 | * If %BIOSET_NEED_RESCUER is set, a workqueue is created which can be used |
| 1735 | * to dispatch queued requests when the mempool runs out of space. |
| 1736 | * |
| 1737 | */ |
| 1738 | int bioset_init(struct bio_set *bs, |
| 1739 | unsigned int pool_size, |
| 1740 | unsigned int front_pad, |
| 1741 | int flags) |
| 1742 | { |
| 1743 | bs->front_pad = front_pad; |
| 1744 | if (flags & BIOSET_NEED_BVECS) |
| 1745 | bs->back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec); |
| 1746 | else |
| 1747 | bs->back_pad = 0; |
| 1748 | |
| 1749 | spin_lock_init(&bs->rescue_lock); |
| 1750 | bio_list_init(&bs->rescue_list); |
| 1751 | INIT_WORK(&bs->rescue_work, bio_alloc_rescue); |
| 1752 | |
| 1753 | bs->bio_slab = bio_find_or_create_slab(bs); |
| 1754 | if (!bs->bio_slab) |
| 1755 | return -ENOMEM; |
| 1756 | |
| 1757 | if (mempool_init_slab_pool(&bs->bio_pool, pool_size, bs->bio_slab)) |
| 1758 | goto bad; |
| 1759 | |
| 1760 | if ((flags & BIOSET_NEED_BVECS) && |
| 1761 | biovec_init_pool(&bs->bvec_pool, pool_size)) |
| 1762 | goto bad; |
| 1763 | |
| 1764 | if (flags & BIOSET_NEED_RESCUER) { |
| 1765 | bs->rescue_workqueue = alloc_workqueue("bioset", |
| 1766 | WQ_MEM_RECLAIM, 0); |
| 1767 | if (!bs->rescue_workqueue) |
| 1768 | goto bad; |
| 1769 | } |
| 1770 | if (flags & BIOSET_PERCPU_CACHE) { |
| 1771 | bs->cache = alloc_percpu(struct bio_alloc_cache); |
| 1772 | if (!bs->cache) |
| 1773 | goto bad; |
| 1774 | cpuhp_state_add_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead); |
| 1775 | } |
| 1776 | |
| 1777 | return 0; |
| 1778 | bad: |
| 1779 | bioset_exit(bs); |
| 1780 | return -ENOMEM; |
| 1781 | } |
| 1782 | EXPORT_SYMBOL(bioset_init); |
| 1783 | |
| 1784 | static int __init init_bio(void) |
| 1785 | { |
| 1786 | int i; |
| 1787 | |
| 1788 | BUILD_BUG_ON(BIO_FLAG_LAST > 8 * sizeof_field(struct bio, bi_flags)); |
| 1789 | |
| 1790 | bio_integrity_init(); |
| 1791 | |
| 1792 | for (i = 0; i < ARRAY_SIZE(bvec_slabs); i++) { |
| 1793 | struct biovec_slab *bvs = bvec_slabs + i; |
| 1794 | |
| 1795 | bvs->slab = kmem_cache_create(bvs->name, |
| 1796 | bvs->nr_vecs * sizeof(struct bio_vec), 0, |
| 1797 | SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); |
| 1798 | } |
| 1799 | |
| 1800 | cpuhp_setup_state_multi(CPUHP_BIO_DEAD, "block/bio:dead", NULL, |
| 1801 | bio_cpu_dead); |
| 1802 | |
| 1803 | if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0, |
| 1804 | BIOSET_NEED_BVECS | BIOSET_PERCPU_CACHE)) |
| 1805 | panic("bio: can't allocate bios\n"); |
| 1806 | |
| 1807 | if (bioset_integrity_create(&fs_bio_set, BIO_POOL_SIZE)) |
| 1808 | panic("bio: can't create integrity pool\n"); |
| 1809 | |
| 1810 | return 0; |
| 1811 | } |
| 1812 | subsys_initcall(init_bio); |