diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2009-12-11 00:52:22 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2009-12-11 00:52:22 +0100 |
| commit | 12fc0f49dc994d8d90dcf3df13f5b1ee5441288d (patch) | |
| tree | 60959c326d01807f3e9a72bd1799717d0166ac6e /drivers/md/dm-io.c | |
| parent | dm mpath: prevent io from work queue while suspended (diff) | |
| download | linux-12fc0f49dc994d8d90dcf3df13f5b1ee5441288d.tar.xz linux-12fc0f49dc994d8d90dcf3df13f5b1ee5441288d.zip | |
dm io: handle empty barriers
Accept empty barriers in dm-io.
dm-io will process empty write barrier requests just like the other
read/write requests.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-io.c')
| -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); } |