diff options
| -rw-r--r-- | drivers/md/dm-io.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c index f6a714c5aab0..10f457ca6af2 100644 --- a/drivers/md/dm-io.c +++ b/drivers/md/dm-io.c @@ -309,7 +309,11 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where, unsigned num_bvecs; sector_t remaining = where->count; - while (remaining) { + /* + * where->count may be zero if rw holds a write barrier and we + * need to send a zero-sized barrier. + */ + do { /* * Allocate a suitably sized-bio. */ @@ -339,7 +343,7 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where, atomic_inc(&io->count); submit_bio(rw, bio); - } + } while (remaining); } static void dispatch_io(int rw, unsigned int num_regions, @@ -360,7 +364,7 @@ static void dispatch_io(int rw, unsigned int num_regions, */ for (i = 0; i < num_regions; i++) { *dp = old_pages; - if (where[i].count) + if (where[i].count || (rw & (1 << BIO_RW_BARRIER))) do_region(rw, i, where + i, dp, io); } |