dm kcopyd: return void from dm_kcopyd_copy()

dm_kcopyd_copy() only ever returns 0 so there is no need for callers to
account for possible failure.  Same goes for dm_kcopyd_zero().

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index 3c7547a..cc101f3 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -741,9 +741,9 @@ static void split_job(struct kcopyd_job *master_job)
 	}
 }
 
-int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
-		   unsigned int num_dests, struct dm_io_region *dests,
-		   unsigned int flags, dm_kcopyd_notify_fn fn, void *context)
+void dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
+		    unsigned int num_dests, struct dm_io_region *dests,
+		    unsigned int flags, dm_kcopyd_notify_fn fn, void *context)
 {
 	struct kcopyd_job *job;
 	int i;
@@ -818,16 +818,14 @@ int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
 		job->progress = 0;
 		split_job(job);
 	}
-
-	return 0;
 }
 EXPORT_SYMBOL(dm_kcopyd_copy);
 
-int dm_kcopyd_zero(struct dm_kcopyd_client *kc,
-		   unsigned num_dests, struct dm_io_region *dests,
-		   unsigned flags, dm_kcopyd_notify_fn fn, void *context)
+void dm_kcopyd_zero(struct dm_kcopyd_client *kc,
+		    unsigned num_dests, struct dm_io_region *dests,
+		    unsigned flags, dm_kcopyd_notify_fn fn, void *context)
 {
-	return dm_kcopyd_copy(kc, NULL, num_dests, dests, flags, fn, context);
+	dm_kcopyd_copy(kc, NULL, num_dests, dests, flags, fn, context);
 }
 EXPORT_SYMBOL(dm_kcopyd_zero);