diff options
Diffstat (limited to 'fs/bio.c')
| -rw-r--r-- | fs/bio.c | 2037 |
1 files changed, 0 insertions, 2037 deletions
diff --git a/fs/bio.c b/fs/bio.c deleted file mode 100644 index 6f0362b77806..000000000000 --- a/fs/bio.c +++ /dev/null @@ -1,2037 +0,0 @@ -/* - * 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 <scsi/sg.h> /* for struct sg_iovec */ - -#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, 0, 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_WAIT | __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_WAIT - * is set, retry with the 1-entry mempool - */ - bvl = kmem_cache_alloc(bvs->slab, __gfp_mask); - if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) { - *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)); - bio->bi_flags = 1 << BIO_UPTODATE; - 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|(1 << BIO_UPTODATE); - atomic_set(&bio->bi_remaining, 1); -} -EXPORT_SYMBOL(bio_reset); - -static void bio_chain_endio(struct bio *bio, int error) -{ - bio_endio(bio->bi_private, error); - bio_put(bio); -} - -/** - * bio_chain - chain bio completions - * - * 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; - atomic_inc(&parent->bi_remaining); -} -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(current->bio_list))) - bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio); - - *current->bio_list = 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_WAIT 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 { - /* - * 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_WAIT; 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(current->bio_list)) - gfp_mask &= ~__GFP_WAIT; - - 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->bi_flags |= 1 << 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) -{ - 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->bi_flags |= 1 << 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; -} -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; - } - } - - return bio; -} -EXPORT_SYMBOL(bio_clone_bioset); - -/** - * bio_get_nr_vecs - return approx number of vecs - * @bdev: I/O target - * - * Return the approximate number of pages we can send to this target. - * There's no guarantee that you will be able to fit this number of pages - * into a bio, it does not account for dynamic restrictions that vary - * on offset. - */ -int bio_get_nr_vecs(struct block_device *bdev) -{ - struct request_queue *q = bdev_get_queue(bdev); - int nr_pages; - - nr_pages = min_t(unsigned, - queue_max_segments(q), - queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1); - - return min_t(unsigned, nr_pages, BIO_MAX_PAGES); - -} -EXPORT_SYMBOL(bio_get_nr_vecs); - -static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page - *page, unsigned int len, unsigned int offset, - unsigned int max_sectors) -{ - 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) > max_sectors) - 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) { - unsigned int prev_bv_len = prev->bv_len; - prev->bv_len += len; - - if (q->merge_bvec_fn) { - struct bvec_merge_data bvm = { - /* prev_bvec is already charged in - bi_size, discharge it in order to - simulate merging updated prev_bvec - as new bvec. */ - .bi_bdev = bio->bi_bdev, - .bi_sector = bio->bi_iter.bi_sector, - .bi_size = bio->bi_iter.bi_size - - prev_bv_len, - .bi_rw = bio->bi_rw, - }; - - if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) { - prev->bv_len -= len; - return 0; - } - } - - goto done; - } - } - - if (bio->bi_vcnt >= bio->bi_max_vecs) - return 0; - - /* - * we might lose a segment or two here, but rather that than - * make this too complex. - */ - - while (bio->bi_phys_segments >= queue_max_segments(q)) { - - if (retried_segments) - return 0; - - retried_segments = 1; - blk_recount_segments(q, bio); - } - - /* - * 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; - - /* - * if queue has other restrictions (eg varying max sector size - * depending on offset), it can specify a merge_bvec_fn in the - * queue to get further control - */ - if (q->merge_bvec_fn) { - struct bvec_merge_data bvm = { - .bi_bdev = bio->bi_bdev, - .bi_sector = bio->bi_iter.bi_sector, - .bi_size = bio->bi_iter.bi_size, - .bi_rw = bio->bi_rw, - }; - - /* - * merge_bvec_fn() returns number of bytes it can accept - * at this offset - */ - if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) { - bvec->bv_page = NULL; - bvec->bv_len = 0; - bvec->bv_offset = 0; - return 0; - } - } - - /* If we may be able to merge these biovecs, force a recount */ - if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec))) - bio->bi_flags &= ~(1 << BIO_SEG_VALID); - - bio->bi_vcnt++; - bio->bi_phys_segments++; - done: - bio->bi_iter.bi_size += len; - return len; -} - -/** - * 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) -{ - return __bio_add_page(q, bio, page, len, offset, - queue_max_hw_sectors(q)); -} -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 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. - */ -int bio_add_page(struct bio *bio, struct page *page, unsigned int len, - unsigned int offset) -{ - struct request_queue *q = bdev_get_queue(bio->bi_bdev); - return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q)); -} -EXPORT_SYMBOL(bio_add_page); - -struct submit_bio_ret { - struct completion event; - int error; -}; - -static void submit_bio_wait_endio(struct bio *bio, int error) -{ - struct submit_bio_ret *ret = bio->bi_private; - - ret->error = 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 nr_sgvecs; - int is_our_pages; - struct sg_iovec sgvecs[]; -}; - -static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio, - const struct sg_iovec *iov, int iov_count, - int is_our_pages) -{ - memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count); - bmd->nr_sgvecs = iov_count; - bmd->is_our_pages = is_our_pages; - bio->bi_private = bmd; -} - -static struct bio_map_data *bio_alloc_map_data(int nr_segs, - unsigned int iov_count, - gfp_t gfp_mask) -{ - if (iov_count > UIO_MAXIOV) - return NULL; - - return kmalloc(sizeof(struct bio_map_data) + - sizeof(struct sg_iovec) * iov_count, gfp_mask); -} - -static int __bio_copy_iov(struct bio *bio, const struct sg_iovec *iov, int iov_count, - int to_user, int from_user, int do_free_page) -{ - int ret = 0, i; - struct bio_vec *bvec; - int iov_idx = 0; - unsigned int iov_off = 0; - - bio_for_each_segment_all(bvec, bio, i) { - char *bv_addr = page_address(bvec->bv_page); - unsigned int bv_len = bvec->bv_len; - - while (bv_len && iov_idx < iov_count) { - unsigned int bytes; - char __user *iov_addr; - - bytes = min_t(unsigned int, - iov[iov_idx].iov_len - iov_off, bv_len); - iov_addr = iov[iov_idx].iov_base + iov_off; - - if (!ret) { - if (to_user) - ret = copy_to_user(iov_addr, bv_addr, - bytes); - - if (from_user) - ret = copy_from_user(bv_addr, iov_addr, - bytes); - - if (ret) - ret = -EFAULT; - } - - bv_len -= bytes; - bv_addr += bytes; - iov_addr += bytes; - iov_off += bytes; - - if (iov[iov_idx].iov_len == iov_off) { - iov_idx++; - iov_off = 0; - } - } - - if (do_free_page) - __free_page(bvec->bv_page); - } - - return ret; -} - -/** - * bio_uncopy_user - finish previously mapped bio - * @bio: bio being terminated - * - * Free pages allocated from bio_copy_user() 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; - struct bio_vec *bvec; - int ret = 0, i; - - 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. - */ - if (current->mm) - ret = __bio_copy_iov(bio, bmd->sgvecs, bmd->nr_sgvecs, - bio_data_dir(bio) == READ, - 0, bmd->is_our_pages); - else if (bmd->is_our_pages) - bio_for_each_segment_all(bvec, bio, i) - __free_page(bvec->bv_page); - } - 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) - * @iov: the iovec. - * @iov_count: number of elements in the iovec - * @write_to_vm: bool indicating writing to pages or not - * @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 sg_iovec *iov, int iov_count, - int write_to_vm, gfp_t gfp_mask) -{ - struct bio_map_data *bmd; - struct bio_vec *bvec; - struct page *page; - struct bio *bio; - int i, ret; - int nr_pages = 0; - unsigned int len = 0; - unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0; - - for (i = 0; i < iov_count; i++) { - unsigned long uaddr; - unsigned long end; - unsigned long start; - - uaddr = (unsigned long)iov[i].iov_base; - end = (uaddr + 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; - len += iov[i].iov_len; - } - - if (offset) - nr_pages++; - - bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask); - if (!bmd) - return ERR_PTR(-ENOMEM); - - ret = -ENOMEM; - bio = bio_kmalloc(gfp_mask, nr_pages); - if (!bio) - goto out_bmd; - - if (!write_to_vm) - 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 ((!write_to_vm && (!map_data || !map_data->null_mapped)) || - (map_data && map_data->from_user)) { - ret = __bio_copy_iov(bio, iov, iov_count, 0, 1, 0); - if (ret) - goto cleanup; - } - - bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1); - return bio; -cleanup: - if (!map_data) - bio_for_each_segment_all(bvec, bio, i) - __free_page(bvec->bv_page); - - bio_put(bio); -out_bmd: - kfree(bmd); - return ERR_PTR(ret); -} - -/** - * bio_copy_user - copy user data to bio - * @q: destination block queue - * @map_data: pointer to the rq_map_data holding pages (if necessary) - * @uaddr: start of user address - * @len: length in bytes - * @write_to_vm: bool indicating writing to pages or not - * @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(struct request_queue *q, struct rq_map_data *map_data, - unsigned long uaddr, unsigned int len, - int write_to_vm, gfp_t gfp_mask) -{ - struct sg_iovec iov; - - iov.iov_base = (void __user *)uaddr; - iov.iov_len = len; - - return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask); -} -EXPORT_SYMBOL(bio_copy_user); - -static struct bio *__bio_map_user_iov(struct request_queue *q, - struct block_device *bdev, - const struct sg_iovec *iov, int iov_count, - int write_to_vm, gfp_t gfp_mask) -{ - int i, j; - int nr_pages = 0; - struct page **pages; - struct bio *bio; - int cur_page = 0; - int ret, offset; - - for (i = 0; i < iov_count; i++) { - unsigned long uaddr = (unsigned long)iov[i].iov_base; - unsigned long len = iov[i].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; - - for (i = 0; i < iov_count; i++) { - unsigned long uaddr = (unsigned long)iov[i].iov_base; - unsigned long len = iov[i].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, - write_to_vm, &pages[cur_page]); - if (ret < local_nr_pages) { - ret = -EFAULT; - goto out_unmap; - } - - offset = uaddr & ~PAGE_MASK; - for (j = cur_page; j < page_limit; j++) { - unsigned int bytes = PAGE_SIZE - offset; - - if (len <= 0) - break; - - if (bytes > len) - bytes = len; - - /* - * sorry... - */ - if (bio_add_pc_page(q, bio, pages[j], bytes, offset) < - bytes) - break; - - 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 (!write_to_vm) - bio->bi_rw |= REQ_WRITE; - - bio->bi_bdev = bdev; - bio->bi_flags |= (1 << BIO_USER_MAPPED); - return bio; - - out_unmap: - for (i = 0; i < nr_pages; i++) { - if(!pages[i]) - break; - page_cache_release(pages[i]); - } - out: - kfree(pages); - bio_put(bio); - return ERR_PTR(ret); -} - -/** - * bio_map_user - map user address into bio - * @q: the struct request_queue for the bio - * @bdev: destination block device - * @uaddr: start of user address - * @len: length in bytes - * @write_to_vm: bool indicating writing to pages or not - * @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(struct request_queue *q, struct block_device *bdev, - unsigned long uaddr, unsigned int len, int write_to_vm, - gfp_t gfp_mask) -{ - struct sg_iovec iov; - - iov.iov_base = (void __user *)uaddr; - iov.iov_len = len; - - return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask); -} -EXPORT_SYMBOL(bio_map_user); - -/** - * bio_map_user_iov - map user sg_iovec table into bio - * @q: the struct request_queue for the bio - * @bdev: destination block device - * @iov: the iovec. - * @iov_count: number of elements in the iovec - * @write_to_vm: bool indicating writing to pages or not - * @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, struct block_device *bdev, - const struct sg_iovec *iov, int iov_count, - int write_to_vm, gfp_t gfp_mask) -{ - struct bio *bio; - - bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm, - gfp_mask); - if (IS_ERR(bio)) - return bio; - - /* - * 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; -} - -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, int err) -{ - bio_put(bio); -} - -static 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) - break; - - data += bytes; - len -= bytes; - offset = 0; - } - - bio->bi_end_io = bio_map_kern_endio; - return 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) -{ - struct bio *bio; - - bio = __bio_map_kern(q, data, len, gfp_mask); - if (IS_ERR(bio)) - return bio; - - if (bio->bi_iter.bi_size == len) - return bio; - - /* - * Don't support partial mappings. - */ - bio_put(bio); - return ERR_PTR(-EINVAL); -} -EXPORT_SYMBOL(bio_map_kern); - -static void bio_copy_kern_endio(struct bio *bio, int err) -{ - struct bio_vec *bvec; - const int read = bio_data_dir(bio) == READ; - struct bio_map_data *bmd = bio->bi_private; - int i; - char *p = bmd->sgvecs[0].iov_base; - - bio_for_each_segment_all(bvec, bio, i) { - char *addr = page_address(bvec->bv_page); - - if (read) - memcpy(p, addr, bvec->bv_len); - - __free_page(bvec->bv_page); - p += bvec->bv_len; - } - - kfree(bmd); - bio_put(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) -{ - struct bio *bio; - struct bio_vec *bvec; - int i; - - bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask); - if (IS_ERR(bio)) - return bio; - - if (!reading) { - void *p = data; - - bio_for_each_segment_all(bvec, bio, i) { - char *addr = page_address(bvec->bv_page); - - memcpy(addr, p, bvec->bv_len); - p += bvec->bv_len; - } - } - - bio->bi_end_io = bio_copy_kern_endio; - - return bio; -} -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); - } -} - -#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 - -/** - * bio_endio - end I/O on a bio - * @bio: bio - * @error: error, if any - * - * Description: - * bio_endio() will end I/O on the whole bio. bio_endio() is the - * preferred way to end I/O on a bio, it takes care of clearing - * BIO_UPTODATE on error. @error is 0 on success, and and one of the - * established -Exxxx (-EIO, for instance) error values in case - * something went wrong. 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, int error) -{ - while (bio) { - BUG_ON(atomic_read(&bio->bi_remaining) <= 0); - - if (error) - clear_bit(BIO_UPTODATE, &bio->bi_flags); - else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) - error = -EIO; - - if (!atomic_dec_and_test(&bio->bi_remaining)) - return; - - /* - * 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; - bio_put(bio); - bio = parent; - } else { - if (bio->bi_end_io) - bio->bi_end_io(bio, error); - bio = NULL; - } - } -} -EXPORT_SYMBOL(bio_endio); - -/** - * bio_endio_nodec - end I/O on a bio, without decrementing bi_remaining - * @bio: bio - * @error: error, if any - * - * For code that has saved and restored bi_end_io; thing hard before using this - * function, probably you should've cloned the entire bio. - **/ -void bio_endio_nodec(struct bio *bio, int error) -{ - atomic_inc(&bio->bi_remaining); - bio_endio(bio, error); -} -EXPORT_SYMBOL(bio_endio_nodec); - -/** - * 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. - * - * 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)); - - 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; - - clear_bit(BIO_SEG_VALID, &bio->bi_flags); - - 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(struct bio_set *bs, 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); - -/** - * 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) -{ - 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; - - bs->bvec_pool = biovec_create_pool(bs, 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; -} -EXPORT_SYMBOL(bioset_create); - -#ifdef CONFIG_BLK_CGROUP -/** - * 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; - struct cgroup_subsys_state *css; - - if (bio->bi_ioc) - return -EBUSY; - - ioc = current->io_context; - if (!ioc) - return -ENOENT; - - /* acquire active ref on @ioc and associate */ - get_io_context_active(ioc); - bio->bi_ioc = ioc; - - /* associate blkcg if exists */ - rcu_read_lock(); - css = task_css(current, blkio_cgrp_id); - if (css && css_tryget(css)) - bio->bi_css = css; - rcu_read_unlock(); - - return 0; -} - -/** - * 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; - } -} - -#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); |