| /* |
| * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public Licens |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- |
| * |
| */ |
| #include <linux/mm.h> |
| #include <linux/swap.h> |
| #include <linux/bio.h> |
| #include <linux/blkdev.h> |
| #include <linux/uio.h> |
| #include <linux/iocontext.h> |
| #include <linux/slab.h> |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/export.h> |
| #include <linux/mempool.h> |
| #include <linux/workqueue.h> |
| #include <linux/cgroup.h> |
| |
| #include <trace/events/block.h> |
| |
| /* |
| * Test patch to inline a certain number of bi_io_vec's inside the bio |
| * itself, to shrink a bio data allocation from two mempool calls to one |
| */ |
| #define BIO_INLINE_VECS 4 |
| |
| /* |
| * if you change this list, also change bvec_alloc or things will |
| * break badly! cannot be bigger than what you can fit into an |
| * unsigned short |
| */ |
| #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) } |
| static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = { |
| BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES), |
| }; |
| #undef BV |
| |
| /* |
| * fs_bio_set is the bio_set containing bio and iovec memory pools used by |
| * IO code that does not need private memory pools. |
| */ |
| struct bio_set *fs_bio_set; |
| EXPORT_SYMBOL(fs_bio_set); |
| |
| /* |
| * Our slab pool management |
| */ |
| struct bio_slab { |
| struct kmem_cache *slab; |
| unsigned int slab_ref; |
| unsigned int slab_size; |
| char name[8]; |
| }; |
| static DEFINE_MUTEX(bio_slab_lock); |
| static struct bio_slab *bio_slabs; |
| static unsigned int bio_slab_nr, bio_slab_max; |
| |
| static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size) |
| { |
| unsigned int sz = sizeof(struct bio) + extra_size; |
| struct kmem_cache *slab = NULL; |
| struct bio_slab *bslab, *new_bio_slabs; |
| unsigned int new_bio_slab_max; |
| unsigned int i, entry = -1; |
| |
| mutex_lock(&bio_slab_lock); |
| |
| i = 0; |
| while (i < bio_slab_nr) { |
| bslab = &bio_slabs[i]; |
| |
| if (!bslab->slab && entry == -1) |
| entry = i; |
| else if (bslab->slab_size == sz) { |
| slab = bslab->slab; |
| bslab->slab_ref++; |
| break; |
| } |
| i++; |
| } |
| |
| if (slab) |
| goto out_unlock; |
| |
| if (bio_slab_nr == bio_slab_max && entry == -1) { |
| new_bio_slab_max = bio_slab_max << 1; |
| new_bio_slabs = krealloc(bio_slabs, |
| new_bio_slab_max * sizeof(struct bio_slab), |
| GFP_KERNEL); |
| if (!new_bio_slabs) |
| goto out_unlock; |
| bio_slab_max = new_bio_slab_max; |
| bio_slabs = new_bio_slabs; |
| } |
| if (entry == -1) |
| entry = bio_slab_nr++; |
| |
| bslab = &bio_slabs[entry]; |
| |
| snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry); |
| slab = kmem_cache_create(bslab->name, sz, ARCH_KMALLOC_MINALIGN, |
| SLAB_HWCACHE_ALIGN, NULL); |
| if (!slab) |
| goto out_unlock; |
| |
| bslab->slab = slab; |
| bslab->slab_ref = 1; |
| bslab->slab_size = sz; |
| out_unlock: |
| mutex_unlock(&bio_slab_lock); |
| return slab; |
| } |
| |
| static void bio_put_slab(struct bio_set *bs) |
| { |
| struct bio_slab *bslab = NULL; |
| unsigned int i; |
| |
| mutex_lock(&bio_slab_lock); |
| |
| for (i = 0; i < bio_slab_nr; i++) { |
| if (bs->bio_slab == bio_slabs[i].slab) { |
| bslab = &bio_slabs[i]; |
| break; |
| } |
| } |
| |
| if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n")) |
| goto out; |
| |
| WARN_ON(!bslab->slab_ref); |
| |
| if (--bslab->slab_ref) |
| goto out; |
| |
| kmem_cache_destroy(bslab->slab); |
| bslab->slab = NULL; |
| |
| out: |
| mutex_unlock(&bio_slab_lock); |
| } |
| |
| unsigned int bvec_nr_vecs(unsigned short idx) |
| { |
| return bvec_slabs[idx].nr_vecs; |
| } |
| |
| void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx) |
| { |
| BIO_BUG_ON(idx >= BIOVEC_NR_POOLS); |
| |
| if (idx == BIOVEC_MAX_IDX) |
| mempool_free(bv, pool); |
| else { |
| struct biovec_slab *bvs = bvec_slabs + idx; |
| |
| kmem_cache_free(bvs->slab, bv); |
| } |
| } |
| |
| struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx, |
| mempool_t *pool) |
| { |
| struct bio_vec *bvl; |
| |
| /* |
| * see comment near bvec_array define! |
| */ |
| switch (nr) { |
| case 1: |
| *idx = 0; |
| break; |
| case 2 ... 4: |
| *idx = 1; |
| break; |
| case 5 ... 16: |
| *idx = 2; |
| break; |
| case 17 ... 64: |
| *idx = 3; |
| break; |
| case 65 ... 128: |
| *idx = 4; |
| break; |
| case 129 ... BIO_MAX_PAGES: |
| *idx = 5; |
| break; |
| default: |
| return NULL; |
| } |
| |
| /* |
| * idx now points to the pool we want to allocate from. only the |
| * 1-vec entry pool is mempool backed. |
| */ |
| if (*idx == BIOVEC_MAX_IDX) { |
| fallback: |
| bvl = mempool_alloc(pool, gfp_mask); |
| } else { |
| struct biovec_slab *bvs = bvec_slabs + *idx; |
| gfp_t __gfp_mask = gfp_mask & ~(__GFP_DIRECT_RECLAIM | __GFP_IO); |
| |
| /* |
| * Make this allocation restricted and don't dump info on |
| * allocation failures, since we'll fallback to the mempool |
| * in case of failure. |
| */ |
| __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN; |
| |
| /* |
| * Try a slab allocation. If this fails and __GFP_DIRECT_RECLAIM |
| * is set, retry with the 1-entry mempool |
| */ |
| bvl = kmem_cache_alloc(bvs->slab, __gfp_mask); |
| if (unlikely(!bvl && (gfp_mask & __GFP_DIRECT_RECLAIM))) { |
| *idx = BIOVEC_MAX_IDX; |
| goto fallback; |
| } |
| } |
| |
| return bvl; |
| } |
| |
| static void __bio_free(struct bio *bio) |
| { |
| bio_disassociate_task(bio); |
| |
| if (bio_integrity(bio)) |
| bio_integrity_free(bio); |
| } |
| |
| static void bio_free(struct bio *bio) |
| { |
| struct bio_set *bs = bio->bi_pool; |
| void *p; |
| |
| __bio_free(bio); |
| |
| if (bs) { |
| if (bio_flagged(bio, BIO_OWNS_VEC)) |
| bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio)); |
| |
| /* |
| * If we have front padding, adjust the bio pointer before freeing |
| */ |
| p = bio; |
| p -= bs->front_pad; |
| |
| mempool_free(p, bs->bio_pool); |
| } else { |
| /* Bio was allocated by bio_kmalloc() */ |
| kfree(bio); |
| } |
| } |
| |
| void bio_init(struct bio *bio) |
| { |
| memset(bio, 0, sizeof(*bio)); |
| atomic_set(&bio->__bi_remaining, 1); |
| atomic_set(&bio->__bi_cnt, 1); |
| } |
| EXPORT_SYMBOL(bio_init); |
| |
| /** |
| * bio_reset - reinitialize a bio |
| * @bio: bio to reset |
| * |
| * Description: |
| * After calling bio_reset(), @bio will be in the same state as a freshly |
| * allocated bio returned bio bio_alloc_bioset() - the only fields that are |
| * preserved are the ones that are initialized by bio_alloc_bioset(). See |
| * comment in struct bio. |
| */ |
| void bio_reset(struct bio *bio) |
| { |
| unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS); |
| |
| __bio_free(bio); |
| |
| memset(bio, 0, BIO_RESET_BYTES); |
| bio->bi_flags = flags; |
| atomic_set(&bio->__bi_remaining, 1); |
| } |
| EXPORT_SYMBOL(bio_reset); |
| |
| static void bio_chain_endio(struct bio *bio) |
| { |
| struct bio *parent = bio->bi_private; |
| |
| parent->bi_error = bio->bi_error; |
| bio_endio(parent); |
| bio_put(bio); |
| } |
| |
| /* |
| * Increment chain count for the bio. Make sure the CHAIN flag update |
| * is visible before the raised count. |
| */ |
| static inline void bio_inc_remaining(struct bio *bio) |
| { |
| bio_set_flag(bio, BIO_CHAIN); |
| smp_mb__before_atomic(); |
| atomic_inc(&bio->__bi_remaining); |
| } |
| |
| /** |
| * bio_chain - chain bio completions |
| * @bio: the target bio |
| * @parent: the @bio's parent bio |
| * |
| * The caller won't have a bi_end_io called when @bio completes - instead, |
| * @parent's bi_end_io won't be called until both @parent and @bio have |
| * completed; the chained bio will also be freed when it completes. |
| * |
| * The caller must not set bi_private or bi_end_io in @bio. |
| */ |
| void bio_chain(struct bio *bio, struct bio *parent) |
| { |
| BUG_ON(bio->bi_private || bio->bi_end_io); |
| |
| bio->bi_private = parent; |
| bio->bi_end_io = bio_chain_endio; |
| bio_inc_remaining(parent); |
| } |
| EXPORT_SYMBOL(bio_chain); |
| |
| static void bio_alloc_rescue(struct work_struct *work) |
| { |
| struct bio_set *bs = container_of(work, struct bio_set, rescue_work); |
| struct bio *bio; |
| |
| while (1) { |
| spin_lock(&bs->rescue_lock); |
| bio = bio_list_pop(&bs->rescue_list); |
| spin_unlock(&bs->rescue_lock); |
| |
| if (!bio) |
| break; |
| |
| generic_make_request(bio); |
| } |
| } |
| |
| static void punt_bios_to_rescuer(struct bio_set *bs) |
| { |
| struct bio_list punt, nopunt; |
| struct bio *bio; |
| |
| /* |
| * In order to guarantee forward progress we must punt only bios that |
| * were allocated from this bio_set; otherwise, if there was a bio on |
| * there for a stacking driver higher up in the stack, processing it |
| * could require allocating bios from this bio_set, and doing that from |
| * our own rescuer would be bad. |
| * |
| * Since bio lists are singly linked, pop them all instead of trying to |
| * remove from the middle of the list: |
| */ |
| |
| bio_list_init(&punt); |
| bio_list_init(&nopunt); |
| |
| while ((bio = bio_list_pop(¤t->bio_list[0]))) |
| bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio); |
| current->bio_list[0] = nopunt; |
| |
| bio_list_init(&nopunt); |
| while ((bio = bio_list_pop(¤t->bio_list[1]))) |
| bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio); |
| current->bio_list[1] = nopunt; |
| |
| spin_lock(&bs->rescue_lock); |
| bio_list_merge(&bs->rescue_list, &punt); |
| spin_unlock(&bs->rescue_lock); |
| |
| queue_work(bs->rescue_workqueue, &bs->rescue_work); |
| } |
| |
| /** |
| * bio_alloc_bioset - allocate a bio for I/O |
| * @gfp_mask: the GFP_ mask given to the slab allocator |
| * @nr_iovecs: number of iovecs to pre-allocate |
| * @bs: the bio_set to allocate from. |
| * |
| * Description: |
| * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is |
| * backed by the @bs's mempool. |
| * |
| * When @bs is not NULL, if %__GFP_DIRECT_RECLAIM is set then bio_alloc will |
| * always be able to allocate a bio. This is due to the mempool guarantees. |
| * To make this work, callers must never allocate more than 1 bio at a time |
| * from this pool. Callers that need to allocate more than 1 bio must always |
| * submit the previously allocated bio for IO before attempting to allocate |
| * a new one. Failure to do so can cause deadlocks under memory pressure. |
| * |
| * Note that when running under generic_make_request() (i.e. any block |
| * driver), bios are not submitted until after you return - see the code in |
| * generic_make_request() that converts recursion into iteration, to prevent |
| * stack overflows. |
| * |
| * This would normally mean allocating multiple bios under |
| * generic_make_request() would be susceptible to deadlocks, but we have |
| * deadlock avoidance code that resubmits any blocked bios from a rescuer |
| * thread. |
| * |
| * However, we do not guarantee forward progress for allocations from other |
| * mempools. Doing multiple allocations from the same mempool under |
| * generic_make_request() should be avoided - instead, use bio_set's front_pad |
| * for per bio allocations. |
| * |
| * RETURNS: |
| * Pointer to new bio on success, NULL on failure. |
| */ |
| struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) |
| { |
| gfp_t saved_gfp = gfp_mask; |
| unsigned front_pad; |
| unsigned inline_vecs; |
| unsigned long idx = BIO_POOL_NONE; |
| struct bio_vec *bvl = NULL; |
| struct bio *bio; |
| void *p; |
| |
| if (!bs) { |
| if (nr_iovecs > UIO_MAXIOV) |
| return NULL; |
| |
| p = kmalloc(sizeof(struct bio) + |
| nr_iovecs * sizeof(struct bio_vec), |
| gfp_mask); |
| front_pad = 0; |
| inline_vecs = nr_iovecs; |
| } else { |
| /* should not use nobvec bioset for nr_iovecs > 0 */ |
| if (WARN_ON_ONCE(!bs->bvec_pool && nr_iovecs > 0)) |
| return NULL; |
| /* |
| * generic_make_request() converts recursion to iteration; this |
| * means if we're running beneath it, any bios we allocate and |
| * submit will not be submitted (and thus freed) until after we |
| * return. |
| * |
| * This exposes us to a potential deadlock if we allocate |
| * multiple bios from the same bio_set() while running |
| * underneath generic_make_request(). If we were to allocate |
| * multiple bios (say a stacking block driver that was splitting |
| * bios), we would deadlock if we exhausted the mempool's |
| * reserve. |
| * |
| * We solve this, and guarantee forward progress, with a rescuer |
| * workqueue per bio_set. If we go to allocate and there are |
| * bios on current->bio_list, we first try the allocation |
| * without __GFP_DIRECT_RECLAIM; if that fails, we punt those |
| * bios we would be blocking to the rescuer workqueue before |
| * we retry with the original gfp_flags. |
| */ |
| |
| if (current->bio_list && |
| (!bio_list_empty(¤t->bio_list[0]) || |
| !bio_list_empty(¤t->bio_list[1]))) |
| gfp_mask &= ~__GFP_DIRECT_RECLAIM; |
| |
| p = mempool_alloc(bs->bio_pool, gfp_mask); |
| if (!p && gfp_mask != saved_gfp) { |
| punt_bios_to_rescuer(bs); |
| gfp_mask = saved_gfp; |
| p = mempool_alloc(bs->bio_pool, gfp_mask); |
| } |
| |
| front_pad = bs->front_pad; |
| inline_vecs = BIO_INLINE_VECS; |
| } |
| |
| if (unlikely(!p)) |
| return NULL; |
| |
| bio = p + front_pad; |
| bio_init(bio); |
| |
| if (nr_iovecs > inline_vecs) { |
| bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool); |
| if (!bvl && gfp_mask != saved_gfp) { |
| punt_bios_to_rescuer(bs); |
| gfp_mask = saved_gfp; |
| bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool); |
| } |
| |
| if (unlikely(!bvl)) |
| goto err_free; |
| |
| bio_set_flag(bio, BIO_OWNS_VEC); |
| } else if (nr_iovecs) { |
| bvl = bio->bi_inline_vecs; |
| } |
| |
| bio->bi_pool = bs; |
| bio->bi_flags |= idx << BIO_POOL_OFFSET; |
| bio->bi_max_vecs = nr_iovecs; |
| bio->bi_io_vec = bvl; |
| return bio; |
| |
| err_free: |
| mempool_free(p, bs->bio_pool); |
| return NULL; |
| } |
| EXPORT_SYMBOL(bio_alloc_bioset); |
| |
| void zero_fill_bio(struct bio *bio) |
| { |
| unsigned long flags; |
| struct bio_vec bv; |
| struct bvec_iter iter; |
| |
| bio_for_each_segment(bv, bio, iter) { |
| char *data = bvec_kmap_irq(&bv, &flags); |
| memset(data, 0, bv.bv_len); |
| flush_dcache_page(bv.bv_page); |
| bvec_kunmap_irq(data, &flags); |
| } |
| } |
| EXPORT_SYMBOL(zero_fill_bio); |
| |
| /** |
| * bio_put - release a reference to a bio |
| * @bio: bio to release reference to |
| * |
| * Description: |
| * Put a reference to a &struct bio, either one you have gotten with |
| * bio_alloc, bio_get or bio_clone. The last put of a bio will free it. |
| **/ |
| void bio_put(struct bio *bio) |
| { |
| if (!bio_flagged(bio, BIO_REFFED)) |
| bio_free(bio); |
| else { |
| BIO_BUG_ON(!atomic_read(&bio->__bi_cnt)); |
| |
| /* |
| * last put frees it |
| */ |
| if (atomic_dec_and_test(&bio->__bi_cnt)) |
| bio_free(bio); |
| } |
| } |
| EXPORT_SYMBOL(bio_put); |
| |
| inline int bio_phys_segments(struct request_queue *q, struct bio *bio) |
| { |
| if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) |
| blk_recount_segments(q, bio); |
| |
| return bio->bi_phys_segments; |
| } |
| EXPORT_SYMBOL(bio_phys_segments); |
| |
| /** |
| * __bio_clone_fast - clone a bio that shares the original bio's biovec |
| * @bio: destination bio |
| * @bio_src: bio to clone |
| * |
| * Clone a &bio. Caller will own the returned bio, but not |
| * the actual data it points to. Reference count of returned |
| * bio will be one. |
| * |
| * Caller must ensure that @bio_src is not freed before @bio. |
| */ |
| void __bio_clone_fast(struct bio *bio, struct bio *bio_src) |
| { |
| BUG_ON(bio->bi_pool && BIO_POOL_IDX(bio) != BIO_POOL_NONE); |
| |
| /* |
| * most users will be overriding ->bi_bdev with a new target, |
| * so we don't set nor calculate new physical/hw segment counts here |
| */ |
| bio->bi_bdev = bio_src->bi_bdev; |
| bio_set_flag(bio, BIO_CLONED); |
| bio->bi_rw = bio_src->bi_rw; |
| bio->bi_iter = bio_src->bi_iter; |
| bio->bi_io_vec = bio_src->bi_io_vec; |
| |
| bio_clone_blkcg_association(bio, bio_src); |
| } |
| EXPORT_SYMBOL(__bio_clone_fast); |
| |
| /** |
| * bio_clone_fast - clone a bio that shares the original bio's biovec |
| * @bio: bio to clone |
| * @gfp_mask: allocation priority |
| * @bs: bio_set to allocate from |
| * |
| * Like __bio_clone_fast, only also allocates the returned bio |
| */ |
| struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs) |
| { |
| struct bio *b; |
| |
| b = bio_alloc_bioset(gfp_mask, 0, bs); |
| if (!b) |
| return NULL; |
| |
| __bio_clone_fast(b, bio); |
| |
| if (bio_integrity(bio)) { |
| int ret; |
| |
| ret = bio_integrity_clone(b, bio, gfp_mask); |
| |
| if (ret < 0) { |
| bio_put(b); |
| return NULL; |
| } |
| } |
| |
| return b; |
| } |
| EXPORT_SYMBOL(bio_clone_fast); |
| |
| /** |
| * bio_clone_bioset - clone a bio |
| * @bio_src: bio to clone |
| * @gfp_mask: allocation priority |
| * @bs: bio_set to allocate from |
| * |
| * Clone bio. Caller will own the returned bio, but not the actual data it |
| * points to. Reference count of returned bio will be one. |
| */ |
| struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask, |
| struct bio_set *bs) |
| { |
| struct bvec_iter iter; |
| struct bio_vec bv; |
| struct bio *bio; |
| |
| /* |
| * Pre immutable biovecs, __bio_clone() used to just do a memcpy from |
| * bio_src->bi_io_vec to bio->bi_io_vec. |
| * |
| * We can't do that anymore, because: |
| * |
| * - The point of cloning the biovec is to produce a bio with a biovec |
| * the caller can modify: bi_idx and bi_bvec_done should be 0. |
| * |
| * - The original bio could've had more than BIO_MAX_PAGES biovecs; if |
| * we tried to clone the whole thing bio_alloc_bioset() would fail. |
| * But the clone should succeed as long as the number of biovecs we |
| * actually need to allocate is fewer than BIO_MAX_PAGES. |
| * |
| * - Lastly, bi_vcnt should not be looked at or relied upon by code |
| * that does not own the bio - reason being drivers don't use it for |
| * iterating over the biovec anymore, so expecting it to be kept up |
| * to date (i.e. for clones that share the parent biovec) is just |
| * asking for trouble and would force extra work on |
| * __bio_clone_fast() anyways. |
| */ |
| |
| bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs); |
| if (!bio) |
| return NULL; |
| |
| bio->bi_bdev = bio_src->bi_bdev; |
| bio->bi_rw = bio_src->bi_rw; |
| bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector; |
| bio->bi_iter.bi_size = bio_src->bi_iter.bi_size; |
| |
| if (bio->bi_rw & REQ_DISCARD) |
| goto integrity_clone; |
| |
| if (bio->bi_rw & REQ_WRITE_SAME) { |
| bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0]; |
| goto integrity_clone; |
| } |
| |
| bio_for_each_segment(bv, bio_src, iter) |
| bio->bi_io_vec[bio->bi_vcnt++] = bv; |
| |
| integrity_clone: |
| if (bio_integrity(bio_src)) { |
| int ret; |
| |
| ret = bio_integrity_clone(bio, bio_src, gfp_mask); |
| if (ret < 0) { |
| bio_put(bio); |
| return NULL; |
| } |
| } |
| |
| bio_clone_blkcg_association(bio, bio_src); |
| |
| return bio; |
| } |
| EXPORT_SYMBOL(bio_clone_bioset); |
| |
| /** |
| * bio_add_pc_page - attempt to add page to bio |
| * @q: the target queue |
| * @bio: destination bio |
| * @page: page to add |
| * @len: vec entry length |
| * @offset: vec entry offset |
| * |
| * Attempt to add a page to the bio_vec maplist. This can fail for a |
| * number of reasons, such as the bio being full or target block device |
| * limitations. The target block device must allow bio's up to PAGE_SIZE, |
| * so it is always possible to add a single page to an empty bio. |
| * |
| * This should only be used by REQ_PC bios. |
| */ |
| int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page |
| *page, unsigned int len, unsigned int offset) |
| { |
| int retried_segments = 0; |
| struct bio_vec *bvec; |
| |
| /* |
| * cloned bio must not modify vec list |
| */ |
| if (unlikely(bio_flagged(bio, BIO_CLONED))) |
| return 0; |
| |
| if (((bio->bi_iter.bi_size + len) >> 9) > queue_max_hw_sectors(q)) |
| return 0; |
| |
| /* |
| * For filesystems with a blocksize smaller than the pagesize |
| * we will often be called with the same page as last time and |
| * a consecutive offset. Optimize this special case. |
| */ |
| if (bio->bi_vcnt > 0) { |
| struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1]; |
| |
| if (page == prev->bv_page && |
| offset == prev->bv_offset + prev->bv_len) { |
| prev->bv_len += len; |
| bio->bi_iter.bi_size += len; |
| goto done; |
| } |
| |
| /* |
| * If the queue doesn't support SG gaps and adding this |
| * offset would create a gap, disallow it. |
| */ |
| if (bvec_gap_to_prev(q, prev, offset)) |
| return 0; |
| } |
| |
| if (bio->bi_vcnt >= bio->bi_max_vecs) |
| return 0; |
| |
| /* |
| * setup the new entry, we might clear it again later if we |
| * cannot add the page |
| */ |
| bvec = &bio->bi_io_vec[bio->bi_vcnt]; |
| bvec->bv_page = page; |
| bvec->bv_len = len; |
| bvec->bv_offset = offset; |
| bio->bi_vcnt++; |
| bio->bi_phys_segments++; |
| bio->bi_iter.bi_size += len; |
| |
| /* |
| * Perform a recount if the number of segments is greater |
| * than queue_max_segments(q). |
| */ |
| |
| while (bio->bi_phys_segments > queue_max_segments(q)) { |
| |
| if (retried_segments) |
| goto failed; |
| |
| retried_segments = 1; |
| blk_recount_segments(q, bio); |
| } |
| |
| /* If we may be able to merge these biovecs, force a recount */ |
| if (bio->bi_vcnt > 1 && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec))) |
| bio_clear_flag(bio, BIO_SEG_VALID); |
| |
| done: |
| return len; |
| |
| failed: |
| bvec->bv_page = NULL; |
| bvec->bv_len = 0; |
| bvec->bv_offset = 0; |
| bio->bi_vcnt--; |
| bio->bi_iter.bi_size -= len; |
| blk_recount_segments(q, bio); |
| return 0; |
| } |
| EXPORT_SYMBOL(bio_add_pc_page); |
| |
| /** |
| * bio_add_page - attempt to add page to bio |
| * @bio: destination bio |
| * @page: page to add |
| * @len: vec entry length |
| * @offset: vec entry offset |
| * |
| * Attempt to add a page to the bio_vec maplist. This will only fail |
| * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio. |
| */ |
| int bio_add_page(struct bio *bio, struct page *page, |
| unsigned int len, unsigned int offset) |
| { |
| struct bio_vec *bv; |
| |
| /* |
| * cloned bio must not modify vec list |
| */ |
| if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) |
| return 0; |
| |
| /* |
| * For filesystems with a blocksize smaller than the pagesize |
| * we will often be called with the same page as last time and |
| * a consecutive offset. Optimize this special case. |
| */ |
| if (bio->bi_vcnt > 0) { |
| bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; |
| |
| if (page == bv->bv_page && |
| offset == bv->bv_offset + bv->bv_len) { |
| bv->bv_len += len; |
| goto done; |
| } |
| } |
| |
| if (bio->bi_vcnt >= bio->bi_max_vecs) |
| return 0; |
| |
| bv = &bio->bi_io_vec[bio->bi_vcnt]; |
| bv->bv_page = page; |
| bv->bv_len = len; |
| bv->bv_offset = offset; |
| |
| bio->bi_vcnt++; |
| done: |
| bio->bi_iter.bi_size += len; |
| return len; |
| } |
| EXPORT_SYMBOL(bio_add_page); |
| |
| struct submit_bio_ret { |
| struct completion event; |
| int error; |
| }; |
| |
| static void submit_bio_wait_endio(struct bio *bio) |
| { |
| struct submit_bio_ret *ret = bio->bi_private; |
| |
| ret->error = bio->bi_error; |
| complete(&ret->event); |
| } |
| |
| /** |
| * submit_bio_wait - submit a bio, and wait until it completes |
| * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) |
| * @bio: The &struct bio which describes the I/O |
| * |
| * Simple wrapper around submit_bio(). Returns 0 on success, or the error from |
| * bio_endio() on failure. |
| */ |
| int submit_bio_wait(int rw, struct bio *bio) |
| { |
| struct submit_bio_ret ret; |
| |
| rw |= REQ_SYNC; |
| init_completion(&ret.event); |
| bio->bi_private = &ret; |
| bio->bi_end_io = submit_bio_wait_endio; |
| submit_bio(rw, bio); |
| wait_for_completion(&ret.event); |
| |
| return ret.error; |
| } |
| EXPORT_SYMBOL(submit_bio_wait); |
| |
| /** |
| * bio_advance - increment/complete a bio by some number of bytes |
| * @bio: bio to advance |
| * @bytes: number of bytes to complete |
| * |
| * This updates bi_sector, bi_size and bi_idx; if the number of bytes to |
| * complete doesn't align with a bvec boundary, then bv_len and bv_offset will |
| * be updated on the last bvec as well. |
| * |
| * @bio will then represent the remaining, uncompleted portion of the io. |
| */ |
| void bio_advance(struct bio *bio, unsigned bytes) |
| { |
| if (bio_integrity(bio)) |
| bio_integrity_advance(bio, bytes); |
| |
| bio_advance_iter(bio, &bio->bi_iter, bytes); |
| } |
| EXPORT_SYMBOL(bio_advance); |
| |
| /** |
| * bio_alloc_pages - allocates a single page for each bvec in a bio |
| * @bio: bio to allocate pages for |
| * @gfp_mask: flags for allocation |
| * |
| * Allocates pages up to @bio->bi_vcnt. |
| * |
| * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are |
| * freed. |
| */ |
| int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask) |
| { |
| int i; |
| struct bio_vec *bv; |
| |
| bio_for_each_segment_all(bv, bio, i) { |
| bv->bv_page = alloc_page(gfp_mask); |
| if (!bv->bv_page) { |
| while (--bv >= bio->bi_io_vec) |
| __free_page(bv->bv_page); |
| return -ENOMEM; |
| } |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(bio_alloc_pages); |
| |
| /** |
| * bio_copy_data - copy contents of data buffers from one chain of bios to |
| * another |
| * @src: source bio list |
| * @dst: destination bio list |
| * |
| * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats |
| * @src and @dst as linked lists of bios. |
| * |
| * Stops when it reaches the end of either @src or @dst - that is, copies |
| * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios). |
| */ |
| void bio_copy_data(struct bio *dst, struct bio *src) |
| { |
| struct bvec_iter src_iter, dst_iter; |
| struct bio_vec src_bv, dst_bv; |
| void *src_p, *dst_p; |
| unsigned bytes; |
| |
| src_iter = src->bi_iter; |
| dst_iter = dst->bi_iter; |
| |
| while (1) { |
| if (!src_iter.bi_size) { |
| src = src->bi_next; |
| if (!src) |
| break; |
| |
| src_iter = src->bi_iter; |
| } |
| |
| if (!dst_iter.bi_size) { |
| dst = dst->bi_next; |
| if (!dst) |
| break; |
| |
| dst_iter = dst->bi_iter; |
| } |
| |
| src_bv = bio_iter_iovec(src, src_iter); |
| dst_bv = bio_iter_iovec(dst, dst_iter); |
| |
| bytes = min(src_bv.bv_len, dst_bv.bv_len); |
| |
| src_p = kmap_atomic(src_bv.bv_page); |
| dst_p = kmap_atomic(dst_bv.bv_page); |
| |
| memcpy(dst_p + dst_bv.bv_offset, |
| src_p + src_bv.bv_offset, |
| bytes); |
| |
| kunmap_atomic(dst_p); |
| kunmap_atomic(src_p); |
| |
| bio_advance_iter(src, &src_iter, bytes); |
| bio_advance_iter(dst, &dst_iter, bytes); |
| } |
| } |
| EXPORT_SYMBOL(bio_copy_data); |
| |
| struct bio_map_data { |
| int is_our_pages; |
| struct iov_iter iter; |
| struct iovec iov[]; |
| }; |
| |
| static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count, |
| gfp_t gfp_mask) |
| { |
| if (iov_count > UIO_MAXIOV) |
| return NULL; |
| |
| return kmalloc(sizeof(struct bio_map_data) + |
| sizeof(struct iovec) * iov_count, gfp_mask); |
| } |
| |
| /** |
| * bio_copy_from_iter - copy all pages from iov_iter to bio |
| * @bio: The &struct bio which describes the I/O as destination |
| * @iter: iov_iter as source |
| * |
| * Copy all pages from iov_iter to bio. |
| * Returns 0 on success, or error on failure. |
| */ |
| static int bio_copy_from_iter(struct bio *bio, struct iov_iter iter) |
| { |
| int i; |
| struct bio_vec *bvec; |
| |
| bio_for_each_segment_all(bvec, bio, i) { |
| ssize_t ret; |
| |
| ret = copy_page_from_iter(bvec->bv_page, |
| bvec->bv_offset, |
| bvec->bv_len, |
| &iter); |
| |
| if (!iov_iter_count(&iter)) |
| break; |
| |
| if (ret < bvec->bv_len) |
| return -EFAULT; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * bio_copy_to_iter - copy all pages from bio to iov_iter |
| * @bio: The &struct bio which describes the I/O as source |
| * @iter: iov_iter as destination |
| * |
| * Copy all pages from bio to iov_iter. |
| * Returns 0 on success, or error on failure. |
| */ |
| static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter) |
| { |
| int i; |
| struct bio_vec *bvec; |
| |
| bio_for_each_segment_all(bvec, bio, i) { |
| ssize_t ret; |
| |
| ret = copy_page_to_iter(bvec->bv_page, |
| bvec->bv_offset, |
| bvec->bv_len, |
| &iter); |
| |
| if (!iov_iter_count(&iter)) |
| break; |
| |
| if (ret < bvec->bv_len) |
| return -EFAULT; |
| } |
| |
| return 0; |
| } |
| |
| static void bio_free_pages(struct bio *bio) |
| { |
| struct bio_vec *bvec; |
| int i; |
| |
| bio_for_each_segment_all(bvec, bio, i) |
| __free_page(bvec->bv_page); |
| } |
| |
| /** |
| * bio_uncopy_user - finish previously mapped bio |
| * @bio: bio being terminated |
| * |
| * Free pages allocated from bio_copy_user_iov() and write back data |
| * to user space in case of a read. |
| */ |
| int bio_uncopy_user(struct bio *bio) |
| { |
| struct bio_map_data *bmd = bio->bi_private; |
| int ret = 0; |
| |
| if (!bio_flagged(bio, BIO_NULL_MAPPED)) { |
| /* |
| * if we're in a workqueue, the request is orphaned, so |
| * don't copy into a random user address space, just free |
| * and return -EINTR so user space doesn't expect any data. |
| */ |
| if (!current->mm) |
| ret = -EINTR; |
| else if (bio_data_dir(bio) == READ) |
| ret = bio_copy_to_iter(bio, bmd->iter); |
| if (bmd->is_our_pages) |
| bio_free_pages(bio); |
| } |
| kfree(bmd); |
| bio_put(bio); |
| return ret; |
| } |
| EXPORT_SYMBOL(bio_uncopy_user); |
| |
| /** |
| * bio_copy_user_iov - copy user data to bio |
| * @q: destination block queue |
| * @map_data: pointer to the rq_map_data holding pages (if necessary) |
| * @iter: iovec iterator |
| * @gfp_mask: memory allocation flags |
| * |
| * Prepares and returns a bio for indirect user io, bouncing data |
| * to/from kernel pages as necessary. Must be paired with |
| * call bio_uncopy_user() on io completion. |
| */ |
| struct bio *bio_copy_user_iov(struct request_queue *q, |
| struct rq_map_data *map_data, |
| const struct iov_iter *iter, |
| gfp_t gfp_mask) |
| { |
| struct bio_map_data *bmd; |
| struct page *page; |
| struct bio *bio; |
| int i, ret; |
| int nr_pages = 0; |
| unsigned int len = iter->count; |
| unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0; |
| |
| for (i = 0; i < iter->nr_segs; i++) { |
| unsigned long uaddr; |
| unsigned long end; |
| unsigned long start; |
| |
| uaddr = (unsigned long) iter->iov[i].iov_base; |
| end = (uaddr + iter->iov[i].iov_len + PAGE_SIZE - 1) |
| >> PAGE_SHIFT; |
| start = uaddr >> PAGE_SHIFT; |
| |
| /* |
| * Overflow, abort |
| */ |
| if (end < start) |
| return ERR_PTR(-EINVAL); |
| |
| nr_pages += end - start; |
| } |
| |
| if (offset) |
| nr_pages++; |
| |
| bmd = bio_alloc_map_data(iter->nr_segs, gfp_mask); |
| if (!bmd) |
| return ERR_PTR(-ENOMEM); |
| |
| /* |
| * We need to do a deep copy of the iov_iter including the iovecs. |
| * The caller provided iov might point to an on-stack or otherwise |
| * shortlived one. |
| */ |
| bmd->is_our_pages = map_data ? 0 : 1; |
| memcpy(bmd->iov, iter->iov, sizeof(struct iovec) * iter->nr_segs); |
| iov_iter_init(&bmd->iter, iter->type, bmd->iov, |
| iter->nr_segs, iter->count); |
| |
| ret = -ENOMEM; |
| bio = bio_kmalloc(gfp_mask, nr_pages); |
| if (!bio) |
| goto out_bmd; |
| |
| if (iter->type & WRITE) |
| bio->bi_rw |= REQ_WRITE; |
| |
| ret = 0; |
| |
| if (map_data) { |
| nr_pages = 1 << map_data->page_order; |
| i = map_data->offset / PAGE_SIZE; |
| } |
| while (len) { |
| unsigned int bytes = PAGE_SIZE; |
| |
| bytes -= offset; |
| |
| if (bytes > len) |
| bytes = len; |
| |
| if (map_data) { |
| if (i == map_data->nr_entries * nr_pages) { |
| ret = -ENOMEM; |
| break; |
| } |
| |
| page = map_data->pages[i / nr_pages]; |
| page += (i % nr_pages); |
| |
| i++; |
| } else { |
| page = alloc_page(q->bounce_gfp | gfp_mask); |
| if (!page) { |
| ret = -ENOMEM; |
| break; |
| } |
| } |
| |
| if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) |
| break; |
| |
| len -= bytes; |
| offset = 0; |
| } |
| |
| if (ret) |
| goto cleanup; |
| |
| /* |
| * success |
| */ |
| if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) || |
| (map_data && map_data->from_user)) { |
| ret = bio_copy_from_iter(bio, *iter); |
| if (ret) |
| goto cleanup; |
| } |
| |
| bio->bi_private = bmd; |
| return bio; |
| cleanup: |
| if (!map_data) |
| bio_free_pages(bio); |
| bio_put(bio); |
| out_bmd: |
| kfree(bmd); |
| return ERR_PTR(ret); |
| } |
| |
| /** |
| * bio_map_user_iov - map user iovec into bio |
| * @q: the struct request_queue for the bio |
| * @iter: iovec iterator |
| * @gfp_mask: memory allocation flags |
| * |
| * Map the user space address into a bio suitable for io to a block |
| * device. Returns an error pointer in case of error. |
| */ |
| struct bio *bio_map_user_iov(struct request_queue *q, |
| const struct iov_iter *iter, |
| gfp_t gfp_mask) |
| { |
| int j; |
| int nr_pages = 0; |
| struct page **pages; |
| struct bio *bio; |
| int cur_page = 0; |
| int ret, offset; |
| struct iov_iter i; |
| struct iovec iov; |
| struct bio_vec *bvec; |
| |
| iov_for_each(iov, i, *iter) { |
| unsigned long uaddr = (unsigned long) iov.iov_base; |
| unsigned long len = iov.iov_len; |
| unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| unsigned long start = uaddr >> PAGE_SHIFT; |
| |
| /* |
| * Overflow, abort |
| */ |
| if (end < start) |
| return ERR_PTR(-EINVAL); |
| |
| nr_pages += end - start; |
| /* |
| * buffer must be aligned to at least hardsector size for now |
| */ |
| if (uaddr & queue_dma_alignment(q)) |
| return ERR_PTR(-EINVAL); |
| } |
| |
| if (!nr_pages) |
| return ERR_PTR(-EINVAL); |
| |
| bio = bio_kmalloc(gfp_mask, nr_pages); |
| if (!bio) |
| return ERR_PTR(-ENOMEM); |
| |
| ret = -ENOMEM; |
| pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask); |
| if (!pages) |
| goto out; |
| |
| iov_for_each(iov, i, *iter) { |
| unsigned long uaddr = (unsigned long) iov.iov_base; |
| unsigned long len = iov.iov_len; |
| unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| unsigned long start = uaddr >> PAGE_SHIFT; |
| const int local_nr_pages = end - start; |
| const int page_limit = cur_page + local_nr_pages; |
| |
| ret = get_user_pages_fast(uaddr, local_nr_pages, |
| (iter->type & WRITE) != WRITE, |
| &pages[cur_page]); |
| if (unlikely(ret < local_nr_pages)) { |
| for (j = cur_page; j < page_limit; j++) { |
| if (!pages[j]) |
| break; |
| put_page(pages[j]); |
| } |
| ret = -EFAULT; |
| goto out_unmap; |
| } |
| |
| offset = uaddr & ~PAGE_MASK; |
| for (j = cur_page; j < page_limit; j++) { |
| unsigned int bytes = PAGE_SIZE - offset; |
| unsigned short prev_bi_vcnt = bio->bi_vcnt; |
| |
| if (len <= 0) |
| break; |
| |
| if (bytes > len) |
| bytes = len; |
| |
| /* |
| * sorry... |
| */ |
| if (bio_add_pc_page(q, bio, pages[j], bytes, offset) < |
| bytes) |
| break; |
| |
| /* |
| * check if vector was merged with previous |
| * drop page reference if needed |
| */ |
| if (bio->bi_vcnt == prev_bi_vcnt) |
| put_page(pages[j]); |
| |
| len -= bytes; |
| offset = 0; |
| } |
| |
| cur_page = j; |
| /* |
| * release the pages we didn't map into the bio, if any |
| */ |
| while (j < page_limit) |
| page_cache_release(pages[j++]); |
| } |
| |
| kfree(pages); |
| |
| /* |
| * set data direction, and check if mapped pages need bouncing |
| */ |
| if (iter->type & WRITE) |
| bio->bi_rw |= REQ_WRITE; |
| |
| bio_set_flag(bio, BIO_USER_MAPPED); |
| |
| /* |
| * subtle -- if __bio_map_user() ended up bouncing a bio, |
| * it would normally disappear when its bi_end_io is run. |
| * however, we need it for the unmap, so grab an extra |
| * reference to it |
| */ |
| bio_get(bio); |
| return bio; |
| |
| out_unmap: |
| bio_for_each_segment_all(bvec, bio, j) { |
| put_page(bvec->bv_page); |
| } |
| out: |
| kfree(pages); |
| bio_put(bio); |
| return ERR_PTR(ret); |
| } |
| |
| static void __bio_unmap_user(struct bio *bio) |
| { |
| struct bio_vec *bvec; |
| int i; |
| |
| /* |
| * make sure we dirty pages we wrote to |
| */ |
| bio_for_each_segment_all(bvec, bio, i) { |
| if (bio_data_dir(bio) == READ) |
| set_page_dirty_lock(bvec->bv_page); |
| |
| page_cache_release(bvec->bv_page); |
| } |
| |
| bio_put(bio); |
| } |
| |
| /** |
| * bio_unmap_user - unmap a bio |
| * @bio: the bio being unmapped |
| * |
| * Unmap a bio previously mapped by bio_map_user(). Must be called with |
| * a process context. |
| * |
| * bio_unmap_user() may sleep. |
| */ |
| void bio_unmap_user(struct bio *bio) |
| { |
| __bio_unmap_user(bio); |
| bio_put(bio); |
| } |
| EXPORT_SYMBOL(bio_unmap_user); |
| |
| static void bio_map_kern_endio(struct bio *bio) |
| { |
| bio_put(bio); |
| } |
| |
| /** |
| * bio_map_kern - map kernel address into bio |
| * @q: the struct request_queue for the bio |
| * @data: pointer to buffer to map |
| * @len: length in bytes |
| * @gfp_mask: allocation flags for bio allocation |
| * |
| * Map the kernel address into a bio suitable for io to a block |
| * device. Returns an error pointer in case of error. |
| */ |
| struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, |
| gfp_t gfp_mask) |
| { |
| unsigned long kaddr = (unsigned long)data; |
| unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| unsigned long start = kaddr >> PAGE_SHIFT; |
| const int nr_pages = end - start; |
| int offset, i; |
| struct bio *bio; |
| |
| bio = bio_kmalloc(gfp_mask, nr_pages); |
| if (!bio) |
| return ERR_PTR(-ENOMEM); |
| |
| offset = offset_in_page(kaddr); |
| for (i = 0; i < nr_pages; i++) { |
| unsigned int bytes = PAGE_SIZE - offset; |
| |
| if (len <= 0) |
| break; |
| |
| if (bytes > len) |
| bytes = len; |
| |
| if (bio_add_pc_page(q, bio, virt_to_page(data), bytes, |
| offset) < bytes) { |
| /* we don't support partial mappings */ |
| bio_put(bio); |
| return ERR_PTR(-EINVAL); |
| } |
| |
| data += bytes; |
| len -= bytes; |
| offset = 0; |
| } |
| |
| bio->bi_end_io = bio_map_kern_endio; |
| return bio; |
| } |
| EXPORT_SYMBOL(bio_map_kern); |
| |
| static void bio_copy_kern_endio(struct bio *bio) |
| { |
| bio_free_pages(bio); |
| bio_put(bio); |
| } |
| |
| static void bio_copy_kern_endio_read(struct bio *bio) |
| { |
| char *p = bio->bi_private; |
| struct bio_vec *bvec; |
| int i; |
| |
| bio_for_each_segment_all(bvec, bio, i) { |
| memcpy(p, page_address(bvec->bv_page), bvec->bv_len); |
| p += bvec->bv_len; |
| } |
| |
| bio_copy_kern_endio(bio); |
| } |
| |
| /** |
| * bio_copy_kern - copy kernel address into bio |
| * @q: the struct request_queue for the bio |
| * @data: pointer to buffer to copy |
| * @len: length in bytes |
| * @gfp_mask: allocation flags for bio and page allocation |
| * @reading: data direction is READ |
| * |
| * copy the kernel address into a bio suitable for io to a block |
| * device. Returns an error pointer in case of error. |
| */ |
| struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len, |
| gfp_t gfp_mask, int reading) |
| { |
| unsigned long kaddr = (unsigned long)data; |
| unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| unsigned long start = kaddr >> PAGE_SHIFT; |
| struct bio *bio; |
| void *p = data; |
| int nr_pages = 0; |
| |
| /* |
| * Overflow, abort |
| */ |
| if (end < start) |
| return ERR_PTR(-EINVAL); |
| |
| nr_pages = end - start; |
| bio = bio_kmalloc(gfp_mask, nr_pages); |
| if (!bio) |
| return ERR_PTR(-ENOMEM); |
| |
| while (len) { |
| struct page *page; |
| unsigned int bytes = PAGE_SIZE; |
| |
| if (bytes > len) |
| bytes = len; |
| |
| page = alloc_page(q->bounce_gfp | gfp_mask); |
| if (!page) |
| goto cleanup; |
| |
| if (!reading) |
| memcpy(page_address(page), p, bytes); |
| |
| if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) |
| break; |
| |
| len -= bytes; |
| p += bytes; |
| } |
| |
| if (reading) { |
| bio->bi_end_io = bio_copy_kern_endio_read; |
| bio->bi_private = data; |
| } else { |
| bio->bi_end_io = bio_copy_kern_endio; |
| bio->bi_rw |= REQ_WRITE; |
| } |
| |
| return bio; |
| |
| cleanup: |
| bio_free_pages(bio); |
| bio_put(bio); |
| return ERR_PTR(-ENOMEM); |
| } |
| EXPORT_SYMBOL(bio_copy_kern); |
| |
| /* |
| * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions |
| * for performing direct-IO in BIOs. |
| * |
| * The problem is that we cannot run set_page_dirty() from interrupt context |
| * because the required locks are not interrupt-safe. So what we can do is to |
| * mark the pages dirty _before_ performing IO. And in interrupt context, |
| * check that the pages are still dirty. If so, fine. If not, redirty them |
| * in process context. |
| * |
| * We special-case compound pages here: normally this means reads into hugetlb |
| * pages. The logic in here doesn't really work right for compound pages |
| * because the VM does not uniformly chase down the head page in all cases. |
| * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't |
| * handle them at all. So we skip compound pages here at an early stage. |
| * |
| * Note that this code is very hard to test under normal circumstances because |
| * direct-io pins the pages with get_user_pages(). This makes |
| * is_page_cache_freeable return false, and the VM will not clean the pages. |
| * But other code (eg, flusher threads) could clean the pages if they are mapped |
| * pagecache. |
| * |
| * Simply disabling the call to bio_set_pages_dirty() is a good way to test the |
| * deferred bio dirtying paths. |
| */ |
| |
| /* |
| * bio_set_pages_dirty() will mark all the bio's pages as dirty. |
| */ |
| void bio_set_pages_dirty(struct bio *bio) |
| { |
| struct bio_vec *bvec; |
| int i; |
| |
| bio_for_each_segment_all(bvec, bio, i) { |
| struct page *page = bvec->bv_page; |
| |
| if (page && !PageCompound(page)) |
| set_page_dirty_lock(page); |
| } |
| } |
| |
| static void bio_release_pages(struct bio *bio) |
| { |
| struct bio_vec *bvec; |
| int i; |
| |
| bio_for_each_segment_all(bvec, bio, i) { |
| struct page *page = bvec->bv_page; |
| |
| if (page) |
| put_page(page); |
| } |
| } |
| |
| /* |
| * bio_check_pages_dirty() will check that all the BIO's pages are still dirty. |
| * If they are, then fine. If, however, some pages are clean then they must |
| * have been written out during the direct-IO read. So we take another ref on |
| * the BIO and the offending pages and re-dirty the pages in process context. |
| * |
| * It is expected that bio_check_pages_dirty() will wholly own the BIO from |
| * here on. It will run one page_cache_release() against each page and will |
| * run one bio_put() against the BIO. |
| */ |
| |
| static void bio_dirty_fn(struct work_struct *work); |
| |
| static DECLARE_WORK(bio_dirty_work, bio_dirty_fn); |
| static DEFINE_SPINLOCK(bio_dirty_lock); |
| static struct bio *bio_dirty_list; |
| |
| /* |
| * This runs in process context |
| */ |
| static void bio_dirty_fn(struct work_struct *work) |
| { |
| unsigned long flags; |
| struct bio *bio; |
| |
| spin_lock_irqsave(&bio_dirty_lock, flags); |
| bio = bio_dirty_list; |
| bio_dirty_list = NULL; |
| spin_unlock_irqrestore(&bio_dirty_lock, flags); |
| |
| while (bio) { |
| struct bio *next = bio->bi_private; |
| |
| bio_set_pages_dirty(bio); |
| bio_release_pages(bio); |
| bio_put(bio); |
| bio = next; |
| } |
| } |
| |
| void bio_check_pages_dirty(struct bio *bio) |
| { |
| struct bio_vec *bvec; |
| int nr_clean_pages = 0; |
| int i; |
| |
| bio_for_each_segment_all(bvec, bio, i) { |
| struct page *page = bvec->bv_page; |
| |
| if (PageDirty(page) || PageCompound(page)) { |
| page_cache_release(page); |
| bvec->bv_page = NULL; |
| } else { |
| nr_clean_pages++; |
| } |
| } |
| |
| if (nr_clean_pages) { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&bio_dirty_lock, flags); |
| bio->bi_private = bio_dirty_list; |
| bio_dirty_list = bio; |
| spin_unlock_irqrestore(&bio_dirty_lock, flags); |
| schedule_work(&bio_dirty_work); |
| } else { |
| bio_put(bio); |
| } |
| } |
| |
| void generic_start_io_acct(int rw, unsigned long sectors, |
| struct hd_struct *part) |
| { |
| int cpu = part_stat_lock(); |
| |
| part_round_stats(cpu, part); |
| part_stat_inc(cpu, part, ios[rw]); |
| part_stat_add(cpu, part, sectors[rw], sectors); |
| part_inc_in_flight(part, rw); |
| |
| part_stat_unlock(); |
| } |
| EXPORT_SYMBOL(generic_start_io_acct); |
| |
| void generic_end_io_acct(int rw, struct hd_struct *part, |
| unsigned long start_time) |
| { |
| unsigned long duration = jiffies - start_time; |
| int cpu = part_stat_lock(); |
| |
| part_stat_add(cpu, part, ticks[rw], duration); |
| part_round_stats(cpu, part); |
| part_dec_in_flight(part, rw); |
| |
| part_stat_unlock(); |
| } |
| EXPORT_SYMBOL(generic_end_io_acct); |
| |
| #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE |
| void bio_flush_dcache_pages(struct bio *bi) |
| { |
| struct bio_vec bvec; |
| struct bvec_iter iter; |
| |
| bio_for_each_segment(bvec, bi, iter) |
| flush_dcache_page(bvec.bv_page); |
| } |
| EXPORT_SYMBOL(bio_flush_dcache_pages); |
| #endif |
| |
| static inline bool bio_remaining_done(struct bio *bio) |
| { |
| /* |
| * If we're not chaining, then ->__bi_remaining is always 1 and |
| * we always end io on the first invocation. |
| */ |
| if (!bio_flagged(bio, BIO_CHAIN)) |
| return true; |
| |
| BUG_ON(atomic_read(&bio->__bi_remaining) <= 0); |
| |
| if (atomic_dec_and_test(&bio->__bi_remaining)) { |
| bio_clear_flag(bio, BIO_CHAIN); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /** |
| * bio_endio - end I/O on a bio |
| * @bio: bio |
| * |
| * Description: |
| * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred |
| * way to end I/O on a bio. No one should call bi_end_io() directly on a |
| * bio unless they own it and thus know that it has an end_io function. |
| **/ |
| void bio_endio(struct bio *bio) |
| { |
| while (bio) { |
| if (unlikely(!bio_remaining_done(bio))) |
| break; |
| |
| /* |
| * Need to have a real endio function for chained bios, |
| * otherwise various corner cases will break (like stacking |
| * block devices that save/restore bi_end_io) - however, we want |
| * to avoid unbounded recursion and blowing the stack. Tail call |
| * optimization would handle this, but compiling with frame |
| * pointers also disables gcc's sibling call optimization. |
| */ |
| if (bio->bi_end_io == bio_chain_endio) { |
| struct bio *parent = bio->bi_private; |
| parent->bi_error = bio->bi_error; |
| bio_put(bio); |
| bio = parent; |
| } else { |
| if (bio->bi_end_io) |
| bio->bi_end_io(bio); |
| bio = NULL; |
| } |
| } |
| } |
| EXPORT_SYMBOL(bio_endio); |
| |
| /** |
| * bio_split - split a bio |
| * @bio: bio to split |
| * @sectors: number of sectors to split from the front of @bio |
| * @gfp: gfp mask |
| * @bs: bio set to allocate from |
| * |
| * Allocates and returns a new bio which represents @sectors from the start of |
| * @bio, and updates @bio to represent the remaining sectors. |
| * |
| * Unless this is a discard request the newly allocated bio will point |
| * to @bio's bi_io_vec; it is the caller's responsibility to ensure that |
| * @bio is not freed before the split. |
| */ |
| struct bio *bio_split(struct bio *bio, int sectors, |
| gfp_t gfp, struct bio_set *bs) |
| { |
| struct bio *split = NULL; |
| |
| BUG_ON(sectors <= 0); |
| BUG_ON(sectors >= bio_sectors(bio)); |
| |
| /* |
| * Discards need a mutable bio_vec to accommodate the payload |
| * required by the DSM TRIM and UNMAP commands. |
| */ |
| if (bio->bi_rw & REQ_DISCARD) |
| split = bio_clone_bioset(bio, gfp, bs); |
| else |
| split = bio_clone_fast(bio, gfp, bs); |
| |
| if (!split) |
| return NULL; |
| |
| split->bi_iter.bi_size = sectors << 9; |
| |
| if (bio_integrity(split)) |
| bio_integrity_trim(split, 0, sectors); |
| |
| bio_advance(bio, split->bi_iter.bi_size); |
| |
| return split; |
| } |
| EXPORT_SYMBOL(bio_split); |
| |
| /** |
| * bio_trim - trim a bio |
| * @bio: bio to trim |
| * @offset: number of sectors to trim from the front of @bio |
| * @size: size we want to trim @bio to, in sectors |
| */ |
| void bio_trim(struct bio *bio, int offset, int size) |
| { |
| /* 'bio' is a cloned bio which we need to trim to match |
| * the given offset and size. |
| */ |
| |
| size <<= 9; |
| if (offset == 0 && size == bio->bi_iter.bi_size) |
| return; |
| |
| bio_clear_flag(bio, BIO_SEG_VALID); |
| |
| bio_advance(bio, offset << 9); |
| |
| bio->bi_iter.bi_size = size; |
| } |
| EXPORT_SYMBOL_GPL(bio_trim); |
| |
| /* |
| * create memory pools for biovec's in a bio_set. |
| * use the global biovec slabs created for general use. |
| */ |
| mempool_t *biovec_create_pool(int pool_entries) |
| { |
| struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX; |
| |
| return mempool_create_slab_pool(pool_entries, bp->slab); |
| } |
| |
| void bioset_free(struct bio_set *bs) |
| { |
| if (bs->rescue_workqueue) |
| destroy_workqueue(bs->rescue_workqueue); |
| |
| if (bs->bio_pool) |
| mempool_destroy(bs->bio_pool); |
| |
| if (bs->bvec_pool) |
| mempool_destroy(bs->bvec_pool); |
| |
| bioset_integrity_free(bs); |
| bio_put_slab(bs); |
| |
| kfree(bs); |
| } |
| EXPORT_SYMBOL(bioset_free); |
| |
| static struct bio_set *__bioset_create(unsigned int pool_size, |
| unsigned int front_pad, |
| bool create_bvec_pool) |
| { |
| unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec); |
| struct bio_set *bs; |
| |
| bs = kzalloc(sizeof(*bs), GFP_KERNEL); |
| if (!bs) |
| return NULL; |
| |
| bs->front_pad = front_pad; |
| |
| spin_lock_init(&bs->rescue_lock); |
| bio_list_init(&bs->rescue_list); |
| INIT_WORK(&bs->rescue_work, bio_alloc_rescue); |
| |
| bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad); |
| if (!bs->bio_slab) { |
| kfree(bs); |
| return NULL; |
| } |
| |
| bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab); |
| if (!bs->bio_pool) |
| goto bad; |
| |
| if (create_bvec_pool) { |
| bs->bvec_pool = biovec_create_pool(pool_size); |
| if (!bs->bvec_pool) |
| goto bad; |
| } |
| |
| bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0); |
| if (!bs->rescue_workqueue) |
| goto bad; |
| |
| return bs; |
| bad: |
| bioset_free(bs); |
| return NULL; |
| } |
| |
| /** |
| * bioset_create - Create a bio_set |
| * @pool_size: Number of bio and bio_vecs to cache in the mempool |
| * @front_pad: Number of bytes to allocate in front of the returned bio |
| * |
| * Description: |
| * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller |
| * to ask for a number of bytes to be allocated in front of the bio. |
| * Front pad allocation is useful for embedding the bio inside |
| * another structure, to avoid allocating extra data to go with the bio. |
| * Note that the bio must be embedded at the END of that structure always, |
| * or things will break badly. |
| */ |
| struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad) |
| { |
| return __bioset_create(pool_size, front_pad, true); |
| } |
| EXPORT_SYMBOL(bioset_create); |
| |
| /** |
| * bioset_create_nobvec - Create a bio_set without bio_vec mempool |
| * @pool_size: Number of bio to cache in the mempool |
| * @front_pad: Number of bytes to allocate in front of the returned bio |
| * |
| * Description: |
| * Same functionality as bioset_create() except that mempool is not |
| * created for bio_vecs. Saving some memory for bio_clone_fast() users. |
| */ |
| struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_pad) |
| { |
| return __bioset_create(pool_size, front_pad, false); |
| } |
| EXPORT_SYMBOL(bioset_create_nobvec); |
| |
| #ifdef CONFIG_BLK_CGROUP |
| |
| /** |
| * bio_associate_blkcg - associate a bio with the specified blkcg |
| * @bio: target bio |
| * @blkcg_css: css of the blkcg to associate |
| * |
| * Associate @bio with the blkcg specified by @blkcg_css. Block layer will |
| * treat @bio as if it were issued by a task which belongs to the blkcg. |
| * |
| * This function takes an extra reference of @blkcg_css which will be put |
| * when @bio is released. The caller must own @bio and is responsible for |
| * synchronizing calls to this function. |
| */ |
| int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css) |
| { |
| if (unlikely(bio->bi_css)) |
| return -EBUSY; |
| css_get(blkcg_css); |
| bio->bi_css = blkcg_css; |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(bio_associate_blkcg); |
| |
| /** |
| * bio_associate_current - associate a bio with %current |
| * @bio: target bio |
| * |
| * Associate @bio with %current if it hasn't been associated yet. Block |
| * layer will treat @bio as if it were issued by %current no matter which |
| * task actually issues it. |
| * |
| * This function takes an extra reference of @task's io_context and blkcg |
| * which will be put when @bio is released. The caller must own @bio, |
| * ensure %current->io_context exists, and is responsible for synchronizing |
| * calls to this function. |
| */ |
| int bio_associate_current(struct bio *bio) |
| { |
| struct io_context *ioc; |
| |
| if (bio->bi_css) |
| return -EBUSY; |
| |
| ioc = current->io_context; |
| if (!ioc) |
| return -ENOENT; |
| |
| get_io_context_active(ioc); |
| bio->bi_ioc = ioc; |
| bio->bi_css = task_get_css(current, io_cgrp_id); |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(bio_associate_current); |
| |
| /** |
| * bio_disassociate_task - undo bio_associate_current() |
| * @bio: target bio |
| */ |
| void bio_disassociate_task(struct bio *bio) |
| { |
| if (bio->bi_ioc) { |
| put_io_context(bio->bi_ioc); |
| bio->bi_ioc = NULL; |
| } |
| if (bio->bi_css) { |
| css_put(bio->bi_css); |
| bio->bi_css = NULL; |
| } |
| } |
| |
| /** |
| * bio_clone_blkcg_association - clone blkcg association from src to dst bio |
| * @dst: destination bio |
| * @src: source bio |
| */ |
| void bio_clone_blkcg_association(struct bio *dst, struct bio *src) |
| { |
| if (src->bi_css) |
| WARN_ON(bio_associate_blkcg(dst, src->bi_css)); |
| } |
| |
| #endif /* CONFIG_BLK_CGROUP */ |
| |
| static void __init biovec_init_slabs(void) |
| { |
| int i; |
| |
| for (i = 0; i < BIOVEC_NR_POOLS; i++) { |
| int size; |
| struct biovec_slab *bvs = bvec_slabs + i; |
| |
| if (bvs->nr_vecs <= BIO_INLINE_VECS) { |
| bvs->slab = NULL; |
| continue; |
| } |
| |
| size = bvs->nr_vecs * sizeof(struct bio_vec); |
| bvs->slab = kmem_cache_create(bvs->name, size, 0, |
| SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
| } |
| } |
| |
| static int __init init_bio(void) |
| { |
| bio_slab_max = 2; |
| bio_slab_nr = 0; |
| bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL); |
| if (!bio_slabs) |
| panic("bio: can't allocate bios\n"); |
| |
| bio_integrity_init(); |
| biovec_init_slabs(); |
| |
| fs_bio_set = bioset_create(BIO_POOL_SIZE, 0); |
| if (!fs_bio_set) |
| panic("bio: can't allocate bios\n"); |
| |
| if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE)) |
| panic("bio: can't create integrity pool\n"); |
| |
| return 0; |
| } |
| subsys_initcall(init_bio); |