dm: per target unplug callback support

Add per-target unplug callback support.

Cc: linux-raid@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 4b1c63d478ab..272496d1fae4 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -197,6 +197,7 @@ struct dm_target {
 struct dm_target_callbacks {
         struct list_head list;
         int (*congested_fn) (struct dm_target_callbacks *, int);
+        void (*unplug_fn)(struct dm_target_callbacks *);
 };
 
 int dm_register_target(struct target_type *t);