[PATCH] dm: extract device limit setting

Separate the setting of device I/O limits from dm_get_device().  dm-loop will
use this.
Signed-off-by: Bryn Reeves <breeves@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/md/dm-table.c

@@ -522,14 +522,9 @@ static int __table_get_device(struct dm_table *t, struct dm_target *ti,
 	return 0;
 }
 
-
-int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
-		  sector_t len, int mode, struct dm_dev **result)
+void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev)
 {
-	int r = __table_get_device(ti->table, ti, path,
-				   start, len, mode, result);
-	if (!r) {
-		request_queue_t *q = bdev_get_queue((*result)->bdev);
+	request_queue_t *q = bdev_get_queue(bdev);
 	struct io_restrictions *rs = &ti->limits;
 
 	/*
@@ -571,7 +566,17 @@ int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
 			     q->seg_boundary_mask);
 
 	rs->no_cluster |= !test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
-	}
+}
+EXPORT_SYMBOL_GPL(dm_set_device_limits);
+
+int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
+		  sector_t len, int mode, struct dm_dev **result)
+{
+	int r = __table_get_device(ti->table, ti, path,
+				   start, len, mode, result);
+
+	if (!r)
+		dm_set_device_limits(ti, (*result)->bdev);
 
 	return r;
 }

include/linux/device-mapper.h

@@ -71,6 +71,11 @@ typedef int (*dm_ioctl_fn) (struct dm_target *ti, struct inode *inode,
 
 void dm_error(const char *message);
 
+/*
+ * Combine device limits.
+ */
+void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev);
+
 /*
  * Constructors should call these functions to ensure destination devices
  * are opened/closed correctly.