[PATCH 03/30] blk-mq: add the blk_mq_alloc_disk APIs

[Christoph Hellwig <hch@xxxxxx>]

Add a new API to allocate a gendisk including the request_queue for use
with blk-mq based drivers.  This is to avoid boilerplate code in drivers.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 block/blk-mq.c         | 19 +++++++++++++++++++
 include/linux/blk-mq.h | 12 ++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 6112741e1ff9..1e6036e6fd66 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3137,6 +3137,25 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
 }
 EXPORT_SYMBOL(blk_mq_init_queue);
 
+struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set, void *queuedata)
+{
+	struct request_queue *q;
+	struct gendisk *disk;
+
+	q = blk_mq_init_queue_data(set, queuedata);
+	if (IS_ERR(q))
+		return ERR_CAST(q);
+
+	disk = __alloc_disk_node(0, set->numa_node);
+	if (!disk) {
+		blk_cleanup_queue(q);
+		return ERR_PTR(-ENOMEM);
+	}
+	disk->queue = q;
+	return disk;
+}
+EXPORT_SYMBOL(__blk_mq_alloc_disk);
+
 /*
  * Helper for setting up a queue with mq ops, given queue depth, and
  * the passed in mq ops flags.
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 73750b2838d2..f496c6c5b5d2 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -426,6 +426,18 @@ enum {
 	((policy & ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1)) \
 		<< BLK_MQ_F_ALLOC_POLICY_START_BIT)
 
+#define blk_mq_alloc_disk(set, queuedata)				\
+({									\
+	static struct lock_class_key __key;				\
+	struct gendisk *__disk = __blk_mq_alloc_disk(set, queuedata);	\
+									\
+	if (__disk)							\
+		lockdep_init_map(&__disk->lockdep_map,			\
+			"(bio completion)", &__key, 0);			\
+	__disk;								\
+})
+struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set,
+		void *queuedata);
 struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *);
 struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set,
 		void *queuedata);
-- 
2.30.2

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