[PATCH 2/3] block: add blk_alloc_disk_srcu

[Ming Lei <ming.lei@redhat.com>]

Add blk_alloc_disk_srcu() so that we can allocate srcu inside request queue
for supporting blocking ->queue_rq().

dm-rq needs this API.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/genhd.c         |  5 +++--
 include/linux/genhd.h | 12 ++++++++----
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 3c139a1b6f04..d21786fbb7bb 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1333,12 +1333,13 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
 }
 EXPORT_SYMBOL(__alloc_disk_node);
 
-struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass)
+struct gendisk *__blk_alloc_disk(int node, bool alloc_srcu,
+		struct lock_class_key *lkclass)
 {
 	struct request_queue *q;
 	struct gendisk *disk;
 
-	q = blk_alloc_queue(node, false);
+	q = blk_alloc_queue(node, alloc_srcu);
 	if (!q)
 		return NULL;
 
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 6906a45bc761..20259340b962 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -227,23 +227,27 @@ void blk_drop_partitions(struct gendisk *disk);
 struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
 		struct lock_class_key *lkclass);
 extern void put_disk(struct gendisk *disk);
-struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass);
+struct gendisk *__blk_alloc_disk(int node, bool alloc_srcu,
+		struct lock_class_key *lkclass);
 
 /**
- * blk_alloc_disk - allocate a gendisk structure
+ * __alloc_disk - allocate a gendisk structure
  * @node_id: numa node to allocate on
+ * @alloc_srcu: allocate srcu instance for supporting blocking ->queue_rq
  *
  * Allocate and pre-initialize a gendisk structure for use with BIO based
  * drivers.
  *
  * Context: can sleep
  */
-#define blk_alloc_disk(node_id)						\
+#define __alloc_disk(node_id, alloc_srcu)				\
 ({									\
 	static struct lock_class_key __key;				\
 									\
-	__blk_alloc_disk(node_id, &__key);				\
+	__blk_alloc_disk(node_id, alloc_srcu, &__key);			\
 })
+#define blk_alloc_disk(node_id) __alloc_disk(node_id, false)
+#define blk_alloc_disk_srcu(node_id) __alloc_disk(node_id, true)
 void blk_cleanup_disk(struct gendisk *disk);
 
 int __register_blkdev(unsigned int major, const char *name,
-- 
2.31.1