[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