/* * Copyright (C) 2001 Jens Axboe * * 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 #include #include #include #include #include #include #include #include #include #include #include #include /* for struct sg_iovec */ #include /* * 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) } 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; printk(KERN_INFO "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; } 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_has_allocated_vec(bio)) bvec_free_bs(bs, 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_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); } EXPORT_SYMBOL(bio_reset); 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_bs(gfp_mask, nr_iovecs, &idx, bs); if (!bvl && gfp_mask != saved_gfp) { punt_bios_to_rescuer(bs); gfp_mask = saved_gfp; bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs); } if (unlikely(!bvl)) goto err_free; } 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; 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_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 - 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_bioset - clone a bio * @bio: bio to clone * @gfp_mask: allocation priority * @bs: bio_set to allocate from * * Like __bio_clone, only also allocates the returned bio */ struct bio *bio_clone_bioset(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs) { struct bio *b; b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, bs); if (!b) return NULL; __bio_clone(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_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 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 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 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, unsigned 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, 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 = 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. 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) { if (error) clear_bit(BIO_UPTODATE, &bio->bi_flags); else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) error = -EIO; trace_block_bio_complete(bio, error); 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 && bi->bi_vcnt != 0); 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; if (bi->bi_vcnt != 0) { bp->bv1 = bi->bi_io_vec[0]; bp->bv2 = bi->bi_io_vec[0]; if (bio_is_rw(bi)) { 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->rescue_workqueue) destroy_workqueue(bs->rescue_workqueue); 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; spin_lock_init(&bs->rescue_lock); bio_list_init(&bs->rescue_list); INIT_WORK(&bs->rescue_work, bio_alloc_rescue); bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad); if (!bs->bio_slab) { kfree(bs); return NULL; } bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab); if (!bs->bio_pool) goto bad; if (biovec_create_pools(bs, pool_size)) 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_subsys_state(current, blkio_subsys_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"); 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);