Re: [dm-devel] [PATCH 2/3] block: add blk_alloc_disk_srcu

[Jeff Moyer <jmoyer@redhat.com>]

Ming Lei <ming.lei@redhat.com> writes:

> 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>

Reviewed-by: Jeff Moyer <jmoyer@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,