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authorJunichi Nomura <j-nomura@ce.jp.nec.com>2014-10-03 11:55:16 +0000
committerMike Snitzer <snitzer@redhat.com>2014-10-05 20:03:34 -0400
commit997782735c0f1e2e069337129fe0d5738d83d19b (patch)
tree981b35bf9ae43c10ddb668eb254827b3ad775e04 /drivers/md
parentd8f429e1669b9709f5b669aac9d734dbe0640891 (diff)
dm: remove nr_iovecs parameter from alloc_tio()
alloc_tio() uses bio_alloc_bioset() to allocate a clone-bio for a bio. alloc_tio() takes the number of bvecs to allocate for the clone-bio. However, with v3.14's immutable biovec changes DM now uses __bio_clone_fast() and no longer needs to allocate bvecs. In practice, the 'nr_iovecs' passed to alloc_tio() is always effectively 0. __clone_and_map_simple_bio() looked like it was passing non-zero nr_iovecs, but its value was always within the range of inline bvecs and no allocation actually happened. If allocation happened, the BUG_ON() in __bio_clone_fast() would've triggered. Remove the nr_iovecs parameter from alloc_tio() to prevent possible future bio_alloc_bioset() mis-use of a new bioset interface that will no longer allow bvecs to be allocated. Also fix extra whitespace before the __bio_clone_fast() call in __clone_and_map_simple_bio(). Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm.c15
1 files changed, 5 insertions, 10 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 32b958dbc499..0b9de07d585b 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1249,13 +1249,13 @@ static void clone_bio(struct dm_target_io *tio, struct bio *bio,
}
static struct dm_target_io *alloc_tio(struct clone_info *ci,
- struct dm_target *ti, int nr_iovecs,
+ struct dm_target *ti,
unsigned target_bio_nr)
{
struct dm_target_io *tio;
struct bio *clone;
- clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, ci->md->bs);
+ clone = bio_alloc_bioset(GFP_NOIO, 0, ci->md->bs);
tio = container_of(clone, struct dm_target_io, clone);
tio->io = ci->io;
@@ -1269,17 +1269,12 @@ static void __clone_and_map_simple_bio(struct clone_info *ci,
struct dm_target *ti,
unsigned target_bio_nr, unsigned *len)
{
- struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs, target_bio_nr);
+ struct dm_target_io *tio = alloc_tio(ci, ti, target_bio_nr);
struct bio *clone = &tio->clone;
tio->len_ptr = len;
- /*
- * Discard requests require the bio's inline iovecs be initialized.
- * ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush
- * and discard, so no need for concern about wasted bvec allocations.
- */
- __bio_clone_fast(clone, ci->bio);
+ __bio_clone_fast(clone, ci->bio);
if (len)
bio_setup_sector(clone, ci->sector, *len);
@@ -1322,7 +1317,7 @@ static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti
num_target_bios = ti->num_write_bios(ti, bio);
for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) {
- tio = alloc_tio(ci, ti, 0, target_bio_nr);
+ tio = alloc_tio(ci, ti, target_bio_nr);
tio->len_ptr = len;
clone_bio(tio, bio, sector, *len);
__map_bio(tio);