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| author |   Andi Kleen <ak@suse.de> | 2009-01-06 03:05:09 +0000 |
|---|---|---|
| committer |   Alasdair G Kergon <agk@redhat.com> | 2009-01-06 03:05:09 +0000 |
| commit | ab4c1424882be9cd70b89abf2b484add355712fa (patch) | |
| tree | 8baed3606be67900df9f02e42fcdb091b78c5def /drivers/md/dm.h | |
| parent | dm request: extend target interface (diff) | |
| download | linux-dev-ab4c1424882be9cd70b89abf2b484add355712fa.tar.xz linux-dev-ab4c1424882be9cd70b89abf2b484add355712fa.zip | |
dm: support barriers on simple devices
Implement barrier support for single device DM devices
This patch implements barrier support in DM for the common case of dm linear
just remapping a single underlying device. In this case we can safely
pass the barrier through because there can be no reordering between
devices.
NB. Any DM device might cease to support barriers if it gets
reconfigured so code must continue to allow for a possible
-EOPNOTSUPP on every barrier bio submitted. - agk
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm.h')
| -rw-r--r-- | drivers/md/dm.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 0ade60cdef42..5b5d08ba9e92 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -51,6 +51,7 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits); * To check the return value from dm_table_find_target(). */ #define dm_target_is_valid(t) ((t)->table) +int dm_table_barrier_ok(struct dm_table *t); /*----------------------------------------------------------------- * A registry of target types. |