[PATCH v4 12/12] block: Only clone bio vecs that are in use
From: Kent Overstreet <hidden>
Date: 2012-07-24 20:14:05
Also in:
dm-devel, lkml
Subsystem:
block layer, device-mapper (lvm), filesystems (vfs and infrastructure), rados block device (rbd), the rest · Maintainers:
Jens Axboe, Alasdair Kergon, Mike Snitzer, Mikulas Patocka, Benjamin Marzinski, Alexander Viro, Christian Brauner, Ilya Dryomov, Linus Torvalds
bcache creates large bios internally, and then splits them according to the device requirements before it sends them down. If a lower level device tries to clone the bio, and the original bio had more than BIO_MAX_PAGES, the clone will fail unecessarily. We can fix this by only cloning the bio vecs that are actually in use. Signed-off-by: Kent Overstreet <redacted> --- drivers/block/rbd.c | 2 +- drivers/md/dm.c | 5 ++--- fs/bio.c | 13 +++++++------ 3 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 692cf05..21edfe5 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c@@ -714,7 +714,7 @@ static struct bio *bio_chain_clone(struct bio **old, struct bio **next, } while (old_chain && (total < len)) { - tmp = bio_kmalloc(gfpmask, old_chain->bi_max_vecs); + tmp = bio_kmalloc(gfpmask, bio_segments(old_chain)); if (!tmp) goto err_out;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 3f3c26e..193fb19 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c@@ -1057,11 +1057,10 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector, { struct bio *clone; - clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs); + clone = bio_alloc_bioset(GFP_NOIO, bv_count, bs); __bio_clone(clone, bio); clone->bi_sector = sector; - clone->bi_idx = idx; - clone->bi_vcnt = idx + bv_count; + clone->bi_vcnt = bv_count; clone->bi_size = to_bytes(len); clone->bi_flags &= ~(1 << BIO_SEG_VALID);
diff --git a/fs/bio.c b/fs/bio.c
index 7a0801d..ec6a357 100644
--- a/fs/bio.c
+++ b/fs/bio.c@@ -451,8 +451,9 @@ EXPORT_SYMBOL(bio_phys_segments); */ 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)); + memcpy(bio->bi_io_vec, + bio_iovec(bio_src), + bio_segments(bio_src) * sizeof(struct bio_vec)); /* * most users will be overriding ->bi_bdev with a new target,
@@ -461,10 +462,10 @@ void __bio_clone(struct bio *bio, struct bio *bio_src) bio->bi_sector = bio_src->bi_sector; bio->bi_bdev = bio_src->bi_bdev; bio->bi_flags |= 1 << BIO_CLONED; + bio->bi_flags &= ~(1 << BIO_SEG_VALID); bio->bi_rw = bio_src->bi_rw; - bio->bi_vcnt = bio_src->bi_vcnt; + bio->bi_vcnt = bio_segments(bio_src); bio->bi_size = bio_src->bi_size; - bio->bi_idx = bio_src->bi_idx; } EXPORT_SYMBOL(__bio_clone);
@@ -479,7 +480,7 @@ EXPORT_SYMBOL(__bio_clone); struct bio *bio_clone_bioset(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs) { - struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, bs); + struct bio *b = bio_alloc_bioset(gfp_mask, bio_segments(bio), bs); if (!b) return NULL;
@@ -509,7 +510,7 @@ EXPORT_SYMBOL(bio_clone); struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask) { - struct bio *b = bio_kmalloc(gfp_mask, bio->bi_max_vecs); + struct bio *b = bio_kmalloc(gfp_mask, bio_segments(bio)); if (!b) return NULL;
--
1.7.7.3