diff options
Diffstat (limited to 'fs/bio.c')
| -rw-r--r-- | fs/bio.c | 1698 |
1 files changed, 1698 insertions, 0 deletions
diff --git a/fs/bio.c b/fs/bio.c new file mode 100644 index 00000000..ef23c521 --- /dev/null +++ b/fs/bio.c @@ -0,0 +1,1698 @@ +/* + * 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/slab.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mempool.h> +#include <linux/workqueue.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 + +static mempool_t *bio_split_pool __read_mostly; + +/* + * 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) } +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; + +/* + * 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; + 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) { + bio_slab_max <<= 1; + bio_slabs = krealloc(bio_slabs, + bio_slab_max * sizeof(struct bio_slab), + GFP_KERNEL); + if (!bio_slabs) + goto out_unlock; + } + 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; + + printk("bio: create slab <%s> at %d\n", bslab->name, entry); + 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_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx) +{ + BIO_BUG_ON(idx >= BIOVEC_NR_POOLS); + + if (idx == BIOVEC_MAX_IDX) + mempool_free(bv, bs->bvec_pool); + else { + struct biovec_slab *bvs = bvec_slabs + idx; + + kmem_cache_free(bvs->slab, bv); + } +} + +struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, + struct bio_set *bs) +{ + 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(bs->bvec_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; +} + +void bio_free(struct bio *bio, struct bio_set *bs) +{ + void *p; + + if (bio_has_allocated_vec(bio)) + bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio)); + + if (bio_integrity(bio)) + bio_integrity_free(bio, bs); + + /* + * If we have front padding, adjust the bio pointer before freeing + */ + p = bio; + if (bs->front_pad) + p -= bs->front_pad; + + mempool_free(p, bs->bio_pool); +} +EXPORT_SYMBOL(bio_free); + +void bio_init(struct bio *bio) +{ + memset(bio, 0, sizeof(*bio)); + bio->bi_flags = 1 << BIO_UPTODATE; + bio->bi_comp_cpu = -1; + atomic_set(&bio->bi_cnt, 1); +} +EXPORT_SYMBOL(bio_init); + +/** + * 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: + * bio_alloc_bioset will try its own mempool to satisfy the allocation. + * If %__GFP_WAIT is set then we will block on the internal pool waiting + * for a &struct bio to become free. + * + * Note that the caller must set ->bi_destructor on successful return + * of a bio, to do the appropriate freeing of the bio once the reference + * count drops to zero. + **/ +struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) +{ + unsigned long idx = BIO_POOL_NONE; + struct bio_vec *bvl = NULL; + struct bio *bio; + void *p; + + p = mempool_alloc(bs->bio_pool, gfp_mask); + if (unlikely(!p)) + return NULL; + bio = p + bs->front_pad; + + bio_init(bio); + + if (unlikely(!nr_iovecs)) + goto out_set; + + if (nr_iovecs <= BIO_INLINE_VECS) { + bvl = bio->bi_inline_vecs; + nr_iovecs = BIO_INLINE_VECS; + } else { + bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs); + if (unlikely(!bvl)) + goto err_free; + + nr_iovecs = bvec_nr_vecs(idx); + } +out_set: + 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); + +static void bio_fs_destructor(struct bio *bio) +{ + bio_free(bio, fs_bio_set); +} + +/** + * bio_alloc - allocate a new bio, memory pool backed + * @gfp_mask: allocation mask to use + * @nr_iovecs: number of iovecs + * + * bio_alloc will allocate a bio and associated bio_vec array that can hold + * at least @nr_iovecs entries. Allocations will be done from the + * fs_bio_set. Also see @bio_alloc_bioset and @bio_kmalloc. + * + * 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 livelocks under memory pressure. + * + * RETURNS: + * Pointer to new bio on success, NULL on failure. + */ +struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs) +{ + struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set); + + if (bio) + bio->bi_destructor = bio_fs_destructor; + + return bio; +} +EXPORT_SYMBOL(bio_alloc); + +static void bio_kmalloc_destructor(struct bio *bio) +{ + if (bio_integrity(bio)) + bio_integrity_free(bio, fs_bio_set); + kfree(bio); +} + +/** + * bio_kmalloc - allocate a bio for I/O using kmalloc() + * @gfp_mask: the GFP_ mask given to the slab allocator + * @nr_iovecs: number of iovecs to pre-allocate + * + * Description: + * Allocate a new bio with @nr_iovecs bvecs. If @gfp_mask contains + * %__GFP_WAIT, the allocation is guaranteed to succeed. + * + **/ +struct bio *bio_kmalloc(gfp_t gfp_mask, int nr_iovecs) +{ + struct bio *bio; + + if (nr_iovecs > UIO_MAXIOV) + return NULL; + + bio = kmalloc(sizeof(struct bio) + nr_iovecs * sizeof(struct bio_vec), + gfp_mask); + if (unlikely(!bio)) + return NULL; + + bio_init(bio); + bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET; + bio->bi_max_vecs = nr_iovecs; + bio->bi_io_vec = bio->bi_inline_vecs; + bio->bi_destructor = bio_kmalloc_destructor; + + return bio; +} +EXPORT_SYMBOL(bio_kmalloc); + +void zero_fill_bio(struct bio *bio) +{ + unsigned long flags; + struct bio_vec *bv; + int i; + + bio_for_each_segment(bv, bio, i) { + 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->bi_next = NULL; + bio->bi_destructor(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 - clone a bio + * @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. + */ +void __bio_clone(struct bio *bio, struct bio *bio_src) +{ + memcpy(bio->bi_io_vec, bio_src->bi_io_vec, + bio_src->bi_max_vecs * sizeof(struct bio_vec)); + + /* + * 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_sector = bio_src->bi_sector; + bio->bi_bdev = bio_src->bi_bdev; + bio->bi_flags |= 1 << BIO_CLONED; + bio->bi_rw = bio_src->bi_rw; + bio->bi_vcnt = bio_src->bi_vcnt; + bio->bi_size = bio_src->bi_size; + bio->bi_idx = bio_src->bi_idx; +} +EXPORT_SYMBOL(__bio_clone); + +/** + * bio_clone - clone a bio + * @bio: bio to clone + * @gfp_mask: allocation priority + * + * Like __bio_clone, only also allocates the returned bio + */ +struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask) +{ + struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set); + + if (!b) + return NULL; + + b->bi_destructor = bio_fs_destructor; + __bio_clone(b, bio); + + if (bio_integrity(bio)) { + int ret; + + ret = bio_integrity_clone(b, bio, gfp_mask, fs_bio_set); + + if (ret < 0) { + bio_put(b); + return NULL; + } + } + + return b; +} +EXPORT_SYMBOL(bio_clone); + +/** + * 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 = ((queue_max_sectors(q) << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT; + if (nr_pages > queue_max_segments(q)) + nr_pages = queue_max_segments(q); + + return nr_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 short 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_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_sector, + .bi_size = bio->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_sector, + .bi_size = bio->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_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 + * smaller than 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 + * smaller than 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 bio_map_data { + struct bio_vec *iovecs; + struct sg_iovec *sgvecs; + int nr_sgvecs; + int is_our_pages; +}; + +static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio, + struct sg_iovec *iov, int iov_count, + int is_our_pages) +{ + memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt); + 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 void bio_free_map_data(struct bio_map_data *bmd) +{ + kfree(bmd->iovecs); + kfree(bmd->sgvecs); + kfree(bmd); +} + +static struct bio_map_data *bio_alloc_map_data(int nr_segs, int iov_count, + gfp_t gfp_mask) +{ + struct bio_map_data *bmd; + + if (iov_count > UIO_MAXIOV) + return NULL; + + bmd = kmalloc(sizeof(*bmd), gfp_mask); + if (!bmd) + return NULL; + + bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask); + if (!bmd->iovecs) { + kfree(bmd); + return NULL; + } + + bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask); + if (bmd->sgvecs) + return bmd; + + kfree(bmd->iovecs); + kfree(bmd); + return NULL; +} + +static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs, + 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(bvec, bio, i, 0) { + char *bv_addr = page_address(bvec->bv_page); + unsigned int bv_len = iovecs[i].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; + int ret = 0; + + if (!bio_flagged(bio, BIO_NULL_MAPPED)) + ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs, + bmd->nr_sgvecs, bio_data_dir(bio) == READ, + 0, bmd->is_our_pages); + bio_free_map_data(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, + 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, bio->bi_io_vec, 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(bvec, bio, i) + __free_page(bvec->bv_page); + + bio_put(bio); +out_bmd: + bio_free_map_data(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, + 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, + 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(bvec, bio, i, 0) { + 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_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(bvec, bio, i, 0) { + char *addr = page_address(bvec->bv_page); + int len = bmd->iovecs[i].bv_len; + + if (read) + memcpy(p, addr, len); + + __free_page(bvec->bv_page); + p += len; + } + + bio_free_map_data(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(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, pdflush) 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 = bio->bi_io_vec; + int i; + + for (i = 0; i < bio->bi_vcnt; i++) { + struct page *page = bvec[i].bv_page; + + if (page && !PageCompound(page)) + set_page_dirty_lock(page); + } +} + +static void bio_release_pages(struct bio *bio) +{ + struct bio_vec *bvec = bio->bi_io_vec; + int i; + + for (i = 0; i < bio->bi_vcnt; i++) { + struct page *page = bvec[i].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 = bio->bi_io_vec; + int nr_clean_pages = 0; + int i; + + for (i = 0; i < bio->bi_vcnt; i++) { + struct page *page = bvec[i].bv_page; + + if (PageDirty(page) || PageCompound(page)) { + page_cache_release(page); + bvec[i].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) +{ + int i; + struct bio_vec *bvec; + + bio_for_each_segment(bvec, bi, i) + 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. Noone 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) +{ + if (error) + clear_bit(BIO_UPTODATE, &bio->bi_flags); + else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) + error = -EIO; + + if (bio->bi_end_io) + bio->bi_end_io(bio, error); +} +EXPORT_SYMBOL(bio_endio); + +void bio_pair_release(struct bio_pair *bp) +{ + if (atomic_dec_and_test(&bp->cnt)) { + struct bio *master = bp->bio1.bi_private; + + bio_endio(master, bp->error); + mempool_free(bp, bp->bio2.bi_private); + } +} +EXPORT_SYMBOL(bio_pair_release); + +static void bio_pair_end_1(struct bio *bi, int err) +{ + struct bio_pair *bp = container_of(bi, struct bio_pair, bio1); + + if (err) + bp->error = err; + + bio_pair_release(bp); +} + +static void bio_pair_end_2(struct bio *bi, int err) +{ + struct bio_pair *bp = container_of(bi, struct bio_pair, bio2); + + if (err) + bp->error = err; + + bio_pair_release(bp); +} + +/* + * split a bio - only worry about a bio with a single page in its iovec + */ +struct bio_pair *bio_split(struct bio *bi, int first_sectors) +{ + struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO); + + if (!bp) + return bp; + + trace_block_split(bdev_get_queue(bi->bi_bdev), bi, + bi->bi_sector + first_sectors); + + BUG_ON(bi->bi_vcnt != 1); + BUG_ON(bi->bi_idx != 0); + atomic_set(&bp->cnt, 3); + bp->error = 0; + bp->bio1 = *bi; + bp->bio2 = *bi; + bp->bio2.bi_sector += first_sectors; + bp->bio2.bi_size -= first_sectors << 9; + bp->bio1.bi_size = first_sectors << 9; + + bp->bv1 = bi->bi_io_vec[0]; + bp->bv2 = bi->bi_io_vec[0]; + bp->bv2.bv_offset += first_sectors << 9; + bp->bv2.bv_len -= first_sectors << 9; + bp->bv1.bv_len = first_sectors << 9; + + bp->bio1.bi_io_vec = &bp->bv1; + bp->bio2.bi_io_vec = &bp->bv2; + + bp->bio1.bi_max_vecs = 1; + bp->bio2.bi_max_vecs = 1; + + bp->bio1.bi_end_io = bio_pair_end_1; + bp->bio2.bi_end_io = bio_pair_end_2; + + bp->bio1.bi_private = bi; + bp->bio2.bi_private = bio_split_pool; + + if (bio_integrity(bi)) + bio_integrity_split(bi, bp, first_sectors); + + return bp; +} +EXPORT_SYMBOL(bio_split); + +/** + * bio_sector_offset - Find hardware sector offset in bio + * @bio: bio to inspect + * @index: bio_vec index + * @offset: offset in bv_page + * + * Return the number of hardware sectors between beginning of bio + * and an end point indicated by a bio_vec index and an offset + * within that vector's page. + */ +sector_t bio_sector_offset(struct bio *bio, unsigned short index, + unsigned int offset) +{ + unsigned int sector_sz; + struct bio_vec *bv; + sector_t sectors; + int i; + + sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue); + sectors = 0; + + if (index >= bio->bi_idx) + index = bio->bi_vcnt - 1; + + __bio_for_each_segment(bv, bio, i, 0) { + if (i == index) { + if (offset > bv->bv_offset) + sectors += (offset - bv->bv_offset) / sector_sz; + break; + } + + sectors += bv->bv_len / sector_sz; + } + + return sectors; +} +EXPORT_SYMBOL(bio_sector_offset); + +/* + * create memory pools for biovec's in a bio_set. + * use the global biovec slabs created for general use. + */ +static int biovec_create_pools(struct bio_set *bs, int pool_entries) +{ + struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX; + + bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab); + if (!bs->bvec_pool) + return -ENOMEM; + + return 0; +} + +static void biovec_free_pools(struct bio_set *bs) +{ + mempool_destroy(bs->bvec_pool); +} + +void bioset_free(struct bio_set *bs) +{ + if (bs->bio_pool) + mempool_destroy(bs->bio_pool); + + bioset_integrity_free(bs); + biovec_free_pools(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; + + 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 (bioset_integrity_create(bs, pool_size)) + goto bad; + + if (!biovec_create_pools(bs, pool_size)) + return bs; + +bad: + bioset_free(bs); + return NULL; +} +EXPORT_SYMBOL(bioset_create); + +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; + +#ifndef CONFIG_BLK_DEV_INTEGRITY + if (bvs->nr_vecs <= BIO_INLINE_VECS) { + bvs->slab = NULL; + continue; + } +#endif + + 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"); + + bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES, + sizeof(struct bio_pair)); + if (!bio_split_pool) + panic("bio: can't create split pool\n"); + + return 0; +} +#ifdef CONFIG_FAST_RESUME +beforeresume_initcall(init_bio); +#else +subsys_initcall(init_bio); +#endif |