| /* |
| * 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 <linux/blktrace_api.h> |
| #include <scsi/sg.h> /* for struct sg_iovec */ |
| |
| #define BIO_POOL_SIZE 2 |
| |
| static struct kmem_cache *bio_slab __read_mostly; |
| |
| #define BIOVEC_NR_POOLS 6 |
| |
| /* |
| * a small number of entries is fine, not going to be performance critical. |
| * basically we just need to survive |
| */ |
| #define BIO_SPLIT_ENTRIES 2 |
| mempool_t *bio_split_pool __read_mostly; |
| |
| struct biovec_slab { |
| int nr_vecs; |
| char *name; |
| struct kmem_cache *slab; |
| }; |
| |
| /* |
| * 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 |
| |
| /* |
| * bio_set is used to allow other portions of the IO system to |
| * allocate their own private memory pools for bio and iovec structures. |
| * These memory pools in turn all allocate from the bio_slab |
| * and the bvec_slabs[]. |
| */ |
| struct bio_set { |
| mempool_t *bio_pool; |
| mempool_t *bvec_pools[BIOVEC_NR_POOLS]; |
| }; |
| |
| /* |
| * fs_bio_set is the bio_set containing bio and iovec memory pools used by |
| * IO code that does not need private memory pools. |
| */ |
| static struct bio_set *fs_bio_set; |
| |
| static inline 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 |
| */ |
| |
| bvl = mempool_alloc(bs->bvec_pools[*idx], gfp_mask); |
| if (bvl) { |
| struct biovec_slab *bp = bvec_slabs + *idx; |
| |
| memset(bvl, 0, bp->nr_vecs * sizeof(struct bio_vec)); |
| } |
| |
| return bvl; |
| } |
| |
| void bio_free(struct bio *bio, struct bio_set *bio_set) |
| { |
| const int pool_idx = BIO_POOL_IDX(bio); |
| |
| BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS); |
| |
| mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]); |
| mempool_free(bio, bio_set->bio_pool); |
| } |
| |
| /* |
| * default destructor for a bio allocated with bio_alloc_bioset() |
| */ |
| static void bio_fs_destructor(struct bio *bio) |
| { |
| bio_free(bio, fs_bio_set); |
| } |
| |
| void bio_init(struct bio *bio) |
| { |
| bio->bi_next = NULL; |
| bio->bi_bdev = NULL; |
| bio->bi_flags = 1 << BIO_UPTODATE; |
| bio->bi_rw = 0; |
| bio->bi_vcnt = 0; |
| bio->bi_idx = 0; |
| bio->bi_phys_segments = 0; |
| bio->bi_hw_segments = 0; |
| bio->bi_hw_front_size = 0; |
| bio->bi_hw_back_size = 0; |
| bio->bi_size = 0; |
| bio->bi_max_vecs = 0; |
| bio->bi_end_io = NULL; |
| atomic_set(&bio->bi_cnt, 1); |
| bio->bi_private = NULL; |
| } |
| |
| /** |
| * 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 first try it's on 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. |
| * |
| * allocate bio and iovecs from the memory pools specified by the |
| * bio_set structure. |
| **/ |
| struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) |
| { |
| struct bio *bio = mempool_alloc(bs->bio_pool, gfp_mask); |
| |
| if (likely(bio)) { |
| struct bio_vec *bvl = NULL; |
| |
| bio_init(bio); |
| if (likely(nr_iovecs)) { |
| unsigned long idx = 0; /* shut up gcc */ |
| |
| bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs); |
| if (unlikely(!bvl)) { |
| mempool_free(bio, bs->bio_pool); |
| bio = NULL; |
| goto out; |
| } |
| bio->bi_flags |= idx << BIO_POOL_OFFSET; |
| bio->bi_max_vecs = bvec_slabs[idx].nr_vecs; |
| } |
| bio->bi_io_vec = bvl; |
| } |
| out: |
| return bio; |
| } |
| |
| 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; |
| } |
| |
| 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 or bio_get. 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); |
| } |
| } |
| |
| 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; |
| } |
| |
| inline int bio_hw_segments(struct request_queue *q, struct bio *bio) |
| { |
| if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) |
| blk_recount_segments(q, bio); |
| |
| return bio->bi_hw_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) |
| { |
| struct request_queue *q = bdev_get_queue(bio_src->bi_bdev); |
| |
| memcpy(bio->bi_io_vec, bio_src->bi_io_vec, |
| bio_src->bi_max_vecs * sizeof(struct bio_vec)); |
| |
| 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; |
| bio_phys_segments(q, bio); |
| bio_hw_segments(q, bio); |
| } |
| |
| /** |
| * 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) { |
| b->bi_destructor = bio_fs_destructor; |
| __bio_clone(b, bio); |
| } |
| |
| return b; |
| } |
| |
| /** |
| * 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 = ((q->max_sectors << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| if (nr_pages > q->max_phys_segments) |
| nr_pages = q->max_phys_segments; |
| if (nr_pages > q->max_hw_segments) |
| nr_pages = q->max_hw_segments; |
| |
| return nr_pages; |
| } |
| |
| 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) { |
| prev->bv_len += len; |
| if (q->merge_bvec_fn && |
| q->merge_bvec_fn(q, bio, prev) < 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 >= q->max_phys_segments |
| || bio->bi_hw_segments >= q->max_hw_segments |
| || BIOVEC_VIRT_OVERSIZE(bio->bi_size)) { |
| |
| 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) { |
| /* |
| * merge_bvec_fn() returns number of bytes it can accept |
| * at this offset |
| */ |
| if (q->merge_bvec_fn(q, bio, bvec) < 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) || |
| BIOVEC_VIRT_MERGEABLE(bvec-1, bvec))) |
| bio->bi_flags &= ~(1 << BIO_SEG_VALID); |
| |
| bio->bi_vcnt++; |
| bio->bi_phys_segments++; |
| bio->bi_hw_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, q->max_hw_sectors); |
| } |
| |
| /** |
| * 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, q->max_sectors); |
| } |
| |
| struct bio_map_data { |
| struct bio_vec *iovecs; |
| void __user *userptr; |
| }; |
| |
| static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio) |
| { |
| memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt); |
| bio->bi_private = bmd; |
| } |
| |
| static void bio_free_map_data(struct bio_map_data *bmd) |
| { |
| kfree(bmd->iovecs); |
| kfree(bmd); |
| } |
| |
| static struct bio_map_data *bio_alloc_map_data(int nr_segs) |
| { |
| struct bio_map_data *bmd = kmalloc(sizeof(*bmd), GFP_KERNEL); |
| |
| if (!bmd) |
| return NULL; |
| |
| bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, GFP_KERNEL); |
| if (bmd->iovecs) |
| return bmd; |
| |
| kfree(bmd); |
| return NULL; |
| } |
| |
| /** |
| * 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; |
| const int read = bio_data_dir(bio) == READ; |
| struct bio_vec *bvec; |
| int i, ret = 0; |
| |
| __bio_for_each_segment(bvec, bio, i, 0) { |
| char *addr = page_address(bvec->bv_page); |
| unsigned int len = bmd->iovecs[i].bv_len; |
| |
| if (read && !ret && copy_to_user(bmd->userptr, addr, len)) |
| ret = -EFAULT; |
| |
| __free_page(bvec->bv_page); |
| bmd->userptr += len; |
| } |
| bio_free_map_data(bmd); |
| bio_put(bio); |
| return ret; |
| } |
| |
| /** |
| * bio_copy_user - copy user data to bio |
| * @q: destination block queue |
| * @uaddr: start of user address |
| * @len: length in bytes |
| * @write_to_vm: bool indicating writing to pages or not |
| * |
| * 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, unsigned long uaddr, |
| unsigned int len, int write_to_vm) |
| { |
| unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| unsigned long start = uaddr >> PAGE_SHIFT; |
| struct bio_map_data *bmd; |
| struct bio_vec *bvec; |
| struct page *page; |
| struct bio *bio; |
| int i, ret; |
| |
| bmd = bio_alloc_map_data(end - start); |
| if (!bmd) |
| return ERR_PTR(-ENOMEM); |
| |
| bmd->userptr = (void __user *) uaddr; |
| |
| ret = -ENOMEM; |
| bio = bio_alloc(GFP_KERNEL, end - start); |
| if (!bio) |
| goto out_bmd; |
| |
| bio->bi_rw |= (!write_to_vm << BIO_RW); |
| |
| ret = 0; |
| while (len) { |
| unsigned int bytes = PAGE_SIZE; |
| |
| if (bytes > len) |
| bytes = len; |
| |
| page = alloc_page(q->bounce_gfp | GFP_KERNEL); |
| if (!page) { |
| ret = -ENOMEM; |
| break; |
| } |
| |
| if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) |
| break; |
| |
| len -= bytes; |
| } |
| |
| if (ret) |
| goto cleanup; |
| |
| /* |
| * success |
| */ |
| if (!write_to_vm) { |
| char __user *p = (char __user *) uaddr; |
| |
| /* |
| * for a write, copy in data to kernel pages |
| */ |
| ret = -EFAULT; |
| bio_for_each_segment(bvec, bio, i) { |
| char *addr = page_address(bvec->bv_page); |
| |
| if (copy_from_user(addr, p, bvec->bv_len)) |
| goto cleanup; |
| p += bvec->bv_len; |
| } |
| } |
| |
| bio_set_map_data(bmd, bio); |
| return bio; |
| cleanup: |
| 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); |
| } |
| |
| 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) |
| { |
| 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; |
| |
| 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_alloc(GFP_KERNEL, nr_pages); |
| if (!bio) |
| return ERR_PTR(-ENOMEM); |
| |
| ret = -ENOMEM; |
| pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL); |
| 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; |
| |
| down_read(¤t->mm->mmap_sem); |
| ret = get_user_pages(current, current->mm, uaddr, |
| local_nr_pages, |
| write_to_vm, 0, &pages[cur_page], NULL); |
| up_read(¤t->mm->mmap_sem); |
| |
| 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 |= (1 << BIO_RW); |
| |
| 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 |
| * |
| * 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) |
| { |
| 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); |
| } |
| |
| /** |
| * 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 |
| * |
| * 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) |
| { |
| struct bio *bio; |
| |
| bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm); |
| |
| 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); |
| } |
| |
| static int bio_map_kern_endio(struct bio *bio, unsigned int bytes_done, int err) |
| { |
| if (bio->bi_size) |
| return 1; |
| |
| bio_put(bio); |
| return 0; |
| } |
| |
| |
| 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_alloc(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); |
| } |
| |
| /* |
| * 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); |
| } |
| } |
| |
| 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); |
| } |
| } |
| |
| /** |
| * bio_endio - end I/O on a bio |
| * @bio: bio |
| * @bytes_done: number of bytes completed |
| * @error: error, if any |
| * |
| * Description: |
| * bio_endio() will end I/O on @bytes_done number of bytes. This may be |
| * just a partial part of the bio, or it may be the whole bio. bio_endio() |
| * is the preferred way to end I/O on a bio, it takes care of decrementing |
| * bi_size and 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, unsigned int bytes_done, int error) |
| { |
| if (error) |
| clear_bit(BIO_UPTODATE, &bio->bi_flags); |
| else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) |
| error = -EIO; |
| |
| if (unlikely(bytes_done > bio->bi_size)) { |
| printk("%s: want %u bytes done, only %u left\n", __FUNCTION__, |
| bytes_done, bio->bi_size); |
| bytes_done = bio->bi_size; |
| } |
| |
| bio->bi_size -= bytes_done; |
| bio->bi_sector += (bytes_done >> 9); |
| |
| if (bio->bi_size && bio->bi_end_io) |
| bio->bi_end_io(bio, bytes_done, error); |
| } |
| |
| 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, master->bi_size, bp->error); |
| mempool_free(bp, bp->bio2.bi_private); |
| } |
| } |
| |
| static int bio_pair_end_1(struct bio * bi, unsigned int done, int err) |
| { |
| struct bio_pair *bp = container_of(bi, struct bio_pair, bio1); |
| |
| if (err) |
| bp->error = err; |
| |
| if (bi->bi_size) |
| return 1; |
| |
| bio_pair_release(bp); |
| return 0; |
| } |
| |
| static int bio_pair_end_2(struct bio * bi, unsigned int done, int err) |
| { |
| struct bio_pair *bp = container_of(bi, struct bio_pair, bio2); |
| |
| if (err) |
| bp->error = err; |
| |
| if (bi->bi_size) |
| return 1; |
| |
| bio_pair_release(bp); |
| return 0; |
| } |
| |
| /* |
| * split a bio - only worry about a bio with a single page |
| * in it's iovec |
| */ |
| struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, int first_sectors) |
| { |
| struct bio_pair *bp = mempool_alloc(pool, GFP_NOIO); |
| |
| if (!bp) |
| return bp; |
| |
| blk_add_trace_pdu_int(bdev_get_queue(bi->bi_bdev), BLK_TA_SPLIT, 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 = pool; |
| |
| return bp; |
| } |
| |
| |
| /* |
| * 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) |
| { |
| int i; |
| |
| for (i = 0; i < BIOVEC_NR_POOLS; i++) { |
| struct biovec_slab *bp = bvec_slabs + i; |
| mempool_t **bvp = bs->bvec_pools + i; |
| |
| *bvp = mempool_create_slab_pool(pool_entries, bp->slab); |
| if (!*bvp) |
| return -ENOMEM; |
| } |
| return 0; |
| } |
| |
| static void biovec_free_pools(struct bio_set *bs) |
| { |
| int i; |
| |
| for (i = 0; i < BIOVEC_NR_POOLS; i++) { |
| mempool_t *bvp = bs->bvec_pools[i]; |
| |
| if (bvp) |
| mempool_destroy(bvp); |
| } |
| |
| } |
| |
| void bioset_free(struct bio_set *bs) |
| { |
| if (bs->bio_pool) |
| mempool_destroy(bs->bio_pool); |
| |
| biovec_free_pools(bs); |
| |
| kfree(bs); |
| } |
| |
| struct bio_set *bioset_create(int bio_pool_size, int bvec_pool_size) |
| { |
| struct bio_set *bs = kzalloc(sizeof(*bs), GFP_KERNEL); |
| |
| if (!bs) |
| return NULL; |
| |
| bs->bio_pool = mempool_create_slab_pool(bio_pool_size, bio_slab); |
| if (!bs->bio_pool) |
| goto bad; |
| |
| if (!biovec_create_pools(bs, bvec_pool_size)) |
| return bs; |
| |
| bad: |
| bioset_free(bs); |
| return NULL; |
| } |
| |
| 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; |
| |
| 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 = KMEM_CACHE(bio, SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
| |
| biovec_init_slabs(); |
| |
| fs_bio_set = bioset_create(BIO_POOL_SIZE, 2); |
| 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; |
| } |
| |
| subsys_initcall(init_bio); |
| |
| EXPORT_SYMBOL(bio_alloc); |
| EXPORT_SYMBOL(bio_put); |
| EXPORT_SYMBOL(bio_free); |
| EXPORT_SYMBOL(bio_endio); |
| EXPORT_SYMBOL(bio_init); |
| EXPORT_SYMBOL(__bio_clone); |
| EXPORT_SYMBOL(bio_clone); |
| EXPORT_SYMBOL(bio_phys_segments); |
| EXPORT_SYMBOL(bio_hw_segments); |
| EXPORT_SYMBOL(bio_add_page); |
| EXPORT_SYMBOL(bio_add_pc_page); |
| EXPORT_SYMBOL(bio_get_nr_vecs); |
| EXPORT_SYMBOL(bio_map_kern); |
| EXPORT_SYMBOL(bio_pair_release); |
| EXPORT_SYMBOL(bio_split); |
| EXPORT_SYMBOL(bio_split_pool); |
| EXPORT_SYMBOL(bio_copy_user); |
| EXPORT_SYMBOL(bio_uncopy_user); |
| EXPORT_SYMBOL(bioset_create); |
| EXPORT_SYMBOL(bioset_free); |
| EXPORT_SYMBOL(bio_alloc_bioset); |