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>

2 files changed, 6 insertions, 0 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 7e2ec3c05550..dffa0ac7c4f0 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1278,6 +1278,7 @@ void dm_table_unplug_all(struct dm_table *t)
 {
         struct dm_dev_internal *dd;
         struct list_head *devices = dm_table_get_devices(t);
+        struct dm_target_callbacks *cb;
 
         list_for_each_entry(dd, devices, list) {
                 struct request_queue *q = bdev_get_queue(dd->dm_dev.bdev);
@@ -1290,6 +1291,10 @@ void dm_table_unplug_all(struct dm_table *t)
                                      dm_device_name(t->md),
                                      bdevname(dd->dm_dev.bdev, b));
         }
+
+        list_for_each_entry(cb, &t->target_callbacks, list)
+                if (cb->unplug_fn)
+                        cb->unplug_fn(cb);
 }
 
 struct mapped_device *dm_table_get_md(struct dm_table *t)
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);