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author | 2013-05-08 10:13:35 -0700 | |
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committer | 2013-05-08 10:13:35 -0700 | |
commit | 4de13d7aa8f4d02f4dc99d4609575659f92b3c5a (patch) | |
tree | 3bc9729eabe79c6164cd29a5d605000bc82bf837 /fs/bio.c | |
parent | Merge branch 'akpm' (incoming from Andrew) (diff) | |
parent | relay: move remove_buf_file inside relay_close_buf (diff) | |
download | linux-4de13d7aa8f4d02f4dc99d4609575659f92b3c5a.tar.gz linux-4de13d7aa8f4d02f4dc99d4609575659f92b3c5a.tar.bz2 linux-4de13d7aa8f4d02f4dc99d4609575659f92b3c5a.zip |
Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block
Pull block core updates from Jens Axboe:
- Major bit is Kents prep work for immutable bio vecs.
- Stable candidate fix for a scheduling-while-atomic in the queue
bypass operation.
- Fix for the hang on exceeded rq->datalen 32-bit unsigned when merging
discard bios.
- Tejuns changes to convert the writeback thread pool to the generic
workqueue mechanism.
- Runtime PM framework, SCSI patches exists on top of these in James'
tree.
- A few random fixes.
* 'for-3.10/core' of git://git.kernel.dk/linux-block: (40 commits)
relay: move remove_buf_file inside relay_close_buf
partitions/efi.c: replace useless kzalloc's by kmalloc's
fs/block_dev.c: fix iov_shorten() criteria in blkdev_aio_read()
block: fix max discard sectors limit
blkcg: fix "scheduling while atomic" in blk_queue_bypass_start
Documentation: cfq-iosched: update documentation help for cfq tunables
writeback: expose the bdi_wq workqueue
writeback: replace custom worker pool implementation with unbound workqueue
writeback: remove unused bdi_pending_list
aoe: Fix unitialized var usage
bio-integrity: Add explicit field for owner of bip_buf
block: Add an explicit bio flag for bios that own their bvec
block: Add bio_alloc_pages()
block: Convert some code to bio_for_each_segment_all()
block: Add bio_for_each_segment_all()
bounce: Refactor __blk_queue_bounce to not use bi_io_vec
raid1: use bio_copy_data()
pktcdvd: Use bio_reset() in disabled code to kill bi_idx usage
pktcdvd: use bio_copy_data()
block: Add bio_copy_data()
...
Diffstat (limited to 'fs/bio.c')
-rw-r--r-- | fs/bio.c | 366 |
1 files changed, 324 insertions, 42 deletions
@@ -161,12 +161,12 @@ 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) +void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx) { BIO_BUG_ON(idx >= BIOVEC_NR_POOLS); if (idx == BIOVEC_MAX_IDX) - mempool_free(bv, bs->bvec_pool); + mempool_free(bv, pool); else { struct biovec_slab *bvs = bvec_slabs + idx; @@ -174,8 +174,8 @@ void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx) } } -struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, - struct bio_set *bs) +struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx, + mempool_t *pool) { struct bio_vec *bvl; @@ -211,7 +211,7 @@ struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, */ if (*idx == BIOVEC_MAX_IDX) { fallback: - bvl = mempool_alloc(bs->bvec_pool, gfp_mask); + bvl = mempool_alloc(pool, gfp_mask); } else { struct biovec_slab *bvs = bvec_slabs + *idx; gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO); @@ -253,8 +253,8 @@ static void bio_free(struct bio *bio) __bio_free(bio); if (bs) { - if (bio_has_allocated_vec(bio)) - bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio)); + if (bio_flagged(bio, BIO_OWNS_VEC)) + bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio)); /* * If we have front padding, adjust the bio pointer before freeing @@ -298,6 +298,54 @@ void bio_reset(struct bio *bio) } 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 @@ -315,11 +363,27 @@ EXPORT_SYMBOL(bio_reset); * 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; @@ -337,7 +401,37 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) 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; } @@ -349,9 +443,17 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) bio_init(bio); if (nr_iovecs > inline_vecs) { - bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs); + bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool); + if (!bvl && gfp_mask != saved_gfp) { + punt_bios_to_rescuer(bs); + gfp_mask = saved_gfp; + bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool); + } + if (unlikely(!bvl)) goto err_free; + + bio->bi_flags |= 1 << BIO_OWNS_VEC; } else if (nr_iovecs) { bvl = bio->bi_inline_vecs; } @@ -653,6 +755,181 @@ int bio_add_page(struct bio *bio, struct page *page, unsigned int len, } EXPORT_SYMBOL(bio_add_page); +struct submit_bio_ret { + struct completion event; + int error; +}; + +static void submit_bio_wait_endio(struct bio *bio, int error) +{ + struct submit_bio_ret *ret = bio->bi_private; + + ret->error = error; + complete(&ret->event); +} + +/** + * submit_bio_wait - submit a bio, and wait until it completes + * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) + * @bio: The &struct bio which describes the I/O + * + * Simple wrapper around submit_bio(). Returns 0 on success, or the error from + * bio_endio() on failure. + */ +int submit_bio_wait(int rw, struct bio *bio) +{ + struct submit_bio_ret ret; + + rw |= REQ_SYNC; + init_completion(&ret.event); + bio->bi_private = &ret; + bio->bi_end_io = submit_bio_wait_endio; + submit_bio(rw, bio); + wait_for_completion(&ret.event); + + return ret.error; +} +EXPORT_SYMBOL(submit_bio_wait); + +/** + * bio_advance - increment/complete a bio by some number of bytes + * @bio: bio to advance + * @bytes: number of bytes to complete + * + * This updates bi_sector, bi_size and bi_idx; if the number of bytes to + * complete doesn't align with a bvec boundary, then bv_len and bv_offset will + * be updated on the last bvec as well. + * + * @bio will then represent the remaining, uncompleted portion of the io. + */ +void bio_advance(struct bio *bio, unsigned bytes) +{ + if (bio_integrity(bio)) + bio_integrity_advance(bio, bytes); + + bio->bi_sector += bytes >> 9; + bio->bi_size -= bytes; + + if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK) + return; + + while (bytes) { + if (unlikely(bio->bi_idx >= bio->bi_vcnt)) { + WARN_ONCE(1, "bio idx %d >= vcnt %d\n", + bio->bi_idx, bio->bi_vcnt); + break; + } + + if (bytes >= bio_iovec(bio)->bv_len) { + bytes -= bio_iovec(bio)->bv_len; + bio->bi_idx++; + } else { + bio_iovec(bio)->bv_len -= bytes; + bio_iovec(bio)->bv_offset += bytes; + bytes = 0; + } + } +} +EXPORT_SYMBOL(bio_advance); + +/** + * bio_alloc_pages - allocates a single page for each bvec in a bio + * @bio: bio to allocate pages for + * @gfp_mask: flags for allocation + * + * Allocates pages up to @bio->bi_vcnt. + * + * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are + * freed. + */ +int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask) +{ + int i; + struct bio_vec *bv; + + bio_for_each_segment_all(bv, bio, i) { + bv->bv_page = alloc_page(gfp_mask); + if (!bv->bv_page) { + while (--bv >= bio->bi_io_vec) + __free_page(bv->bv_page); + return -ENOMEM; + } + } + + return 0; +} +EXPORT_SYMBOL(bio_alloc_pages); + +/** + * bio_copy_data - copy contents of data buffers from one chain of bios to + * another + * @src: source bio list + * @dst: destination bio list + * + * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats + * @src and @dst as linked lists of bios. + * + * Stops when it reaches the end of either @src or @dst - that is, copies + * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios). + */ +void bio_copy_data(struct bio *dst, struct bio *src) +{ + struct bio_vec *src_bv, *dst_bv; + unsigned src_offset, dst_offset, bytes; + void *src_p, *dst_p; + + src_bv = bio_iovec(src); + dst_bv = bio_iovec(dst); + + src_offset = src_bv->bv_offset; + dst_offset = dst_bv->bv_offset; + + while (1) { + if (src_offset == src_bv->bv_offset + src_bv->bv_len) { + src_bv++; + if (src_bv == bio_iovec_idx(src, src->bi_vcnt)) { + src = src->bi_next; + if (!src) + break; + + src_bv = bio_iovec(src); + } + + src_offset = src_bv->bv_offset; + } + + if (dst_offset == dst_bv->bv_offset + dst_bv->bv_len) { + dst_bv++; + if (dst_bv == bio_iovec_idx(dst, dst->bi_vcnt)) { + dst = dst->bi_next; + if (!dst) + break; + + dst_bv = bio_iovec(dst); + } + + dst_offset = dst_bv->bv_offset; + } + + bytes = min(dst_bv->bv_offset + dst_bv->bv_len - dst_offset, + src_bv->bv_offset + src_bv->bv_len - src_offset); + + src_p = kmap_atomic(src_bv->bv_page); + dst_p = kmap_atomic(dst_bv->bv_page); + + memcpy(dst_p + dst_bv->bv_offset, + src_p + src_bv->bv_offset, + bytes); + + kunmap_atomic(dst_p); + kunmap_atomic(src_p); + + src_offset += bytes; + dst_offset += bytes; + } +} +EXPORT_SYMBOL(bio_copy_data); + struct bio_map_data { struct bio_vec *iovecs; struct sg_iovec *sgvecs; @@ -715,7 +992,7 @@ static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs, int iov_idx = 0; unsigned int iov_off = 0; - __bio_for_each_segment(bvec, bio, i, 0) { + bio_for_each_segment_all(bvec, bio, i) { char *bv_addr = page_address(bvec->bv_page); unsigned int bv_len = iovecs[i].bv_len; @@ -897,7 +1174,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q, return bio; cleanup: if (!map_data) - bio_for_each_segment(bvec, bio, i) + bio_for_each_segment_all(bvec, bio, i) __free_page(bvec->bv_page); bio_put(bio); @@ -1111,7 +1388,7 @@ static void __bio_unmap_user(struct bio *bio) /* * make sure we dirty pages we wrote to */ - __bio_for_each_segment(bvec, bio, i, 0) { + bio_for_each_segment_all(bvec, bio, i) { if (bio_data_dir(bio) == READ) set_page_dirty_lock(bvec->bv_page); @@ -1217,7 +1494,7 @@ static void bio_copy_kern_endio(struct bio *bio, int err) int i; char *p = bmd->sgvecs[0].iov_base; - __bio_for_each_segment(bvec, bio, i, 0) { + bio_for_each_segment_all(bvec, bio, i) { char *addr = page_address(bvec->bv_page); int len = bmd->iovecs[i].bv_len; @@ -1257,7 +1534,7 @@ struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len, if (!reading) { void *p = data; - bio_for_each_segment(bvec, bio, i) { + bio_for_each_segment_all(bvec, bio, i) { char *addr = page_address(bvec->bv_page); memcpy(addr, p, bvec->bv_len); @@ -1302,11 +1579,11 @@ EXPORT_SYMBOL(bio_copy_kern); */ void bio_set_pages_dirty(struct bio *bio) { - struct bio_vec *bvec = bio->bi_io_vec; + struct bio_vec *bvec; int i; - for (i = 0; i < bio->bi_vcnt; i++) { - struct page *page = bvec[i].bv_page; + bio_for_each_segment_all(bvec, bio, i) { + struct page *page = bvec->bv_page; if (page && !PageCompound(page)) set_page_dirty_lock(page); @@ -1315,11 +1592,11 @@ void bio_set_pages_dirty(struct bio *bio) static void bio_release_pages(struct bio *bio) { - struct bio_vec *bvec = bio->bi_io_vec; + struct bio_vec *bvec; int i; - for (i = 0; i < bio->bi_vcnt; i++) { - struct page *page = bvec[i].bv_page; + bio_for_each_segment_all(bvec, bio, i) { + struct page *page = bvec->bv_page; if (page) put_page(page); @@ -1368,16 +1645,16 @@ static void bio_dirty_fn(struct work_struct *work) void bio_check_pages_dirty(struct bio *bio) { - struct bio_vec *bvec = bio->bi_io_vec; + struct bio_vec *bvec; int nr_clean_pages = 0; int i; - for (i = 0; i < bio->bi_vcnt; i++) { - struct page *page = bvec[i].bv_page; + bio_for_each_segment_all(bvec, bio, i) { + struct page *page = bvec->bv_page; if (PageDirty(page) || PageCompound(page)) { page_cache_release(page); - bvec[i].bv_page = NULL; + bvec->bv_page = NULL; } else { nr_clean_pages++; } @@ -1478,8 +1755,7 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors) 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); + BUG_ON(bio_segments(bi) > 1); atomic_set(&bp->cnt, 3); bp->error = 0; bp->bio1 = *bi; @@ -1489,8 +1765,8 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors) 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]; + bp->bv1 = *bio_iovec(bi); + bp->bv2 = *bio_iovec(bi); if (bio_is_rw(bi)) { bp->bv2.bv_offset += first_sectors << 9; @@ -1542,7 +1818,7 @@ sector_t bio_sector_offset(struct bio *bio, unsigned short index, if (index >= bio->bi_idx) index = bio->bi_vcnt - 1; - __bio_for_each_segment(bv, bio, i, 0) { + bio_for_each_segment_all(bv, bio, i) { if (i == index) { if (offset > bv->bv_offset) sectors += (offset - bv->bv_offset) / sector_sz; @@ -1560,29 +1836,25 @@ 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) +mempool_t *biovec_create_pool(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); + return mempool_create_slab_pool(pool_entries, bp->slab); } void bioset_free(struct bio_set *bs) { + if (bs->rescue_workqueue) + destroy_workqueue(bs->rescue_workqueue); + if (bs->bio_pool) mempool_destroy(bs->bio_pool); + if (bs->bvec_pool) + mempool_destroy(bs->bvec_pool); + bioset_integrity_free(bs); - biovec_free_pools(bs); bio_put_slab(bs); kfree(bs); @@ -1613,6 +1885,10 @@ struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad) 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); @@ -1623,9 +1899,15 @@ struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad) if (!bs->bio_pool) goto bad; - if (!biovec_create_pools(bs, pool_size)) - return bs; + bs->bvec_pool = biovec_create_pool(bs, pool_size); + if (!bs->bvec_pool) + goto bad; + + bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0); + if (!bs->rescue_workqueue) + goto bad; + return bs; bad: bioset_free(bs); return NULL; |