From: NeilBrown <[email-masked]>

Add per-target unplug callback support.

Cc: [email-masked]
Signed-off-by: NeilBrown <[email-masked]>
Signed-off-by: Jonathan Brassow <[email-masked]>
Signed-off-by: Mike Snitzer <[email-masked]>
Signed-off-by: Alasdair G Kergon <[email-masked]>

---
drivers/md/dm-raid.c          |   10 ++++++++++
 drivers/md/dm-table.c         |    5 +++++
 include/linux/device-mapper.h |    1 +
 2 files changed, 6 insertions(+)

Index: linux-2.6.37/drivers/md/dm-table.c
===================================================================
--- linux-2.6.37.orig/drivers/md/dm-table.c
+++ linux-2.6.37/drivers/md/dm-table.c
@@ -1278,6 +1278,7 @@ void dm_table_unplug_all(struct dm_table
 {
 	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
 				     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)
Index: linux-2.6.37/include/linux/device-mapper.h
===================================================================
--- linux-2.6.37.orig/include/linux/device-mapper.h
+++ linux-2.6.37/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);