Commit 7a18312c authored by Bart Van Assche's avatar Bart Van Assche Committed by Jens Axboe
Browse files

block: Document all members of blk_mq_tag_set and bkl_mq_queue_map 



The meaning of several member variables of these two data structures is
nontrivial. Hence document all member variables using the kernel-doc
syntax.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 73f1c77e

include/linux/blk-mq.h

+43 −11
Original line number Diff line number Diff line
@@ -76,6 +76,16 @@ struct blk_mq_hw_ctx { 
	struct srcu_struct	srcu[0];

};



/**

 * struct blk_mq_queue_map - ctx -> hctx mapping

 * @mq_map:       CPU ID to hardware queue index map. This is an array

 *	with nr_cpu_ids elements. Each element has a value in the range

 *	[@queue_offset, @queue_offset + @nr_queues).

 * @nr_queues:    Number of hardware queues to map CPU IDs onto.

 * @queue_offset: First hardware queue to map onto. Used by the PCIe NVMe

 *	driver to map each hardware queue type (enum hctx_type) onto a distinct

 *	set of hardware queues.

 */

struct blk_mq_queue_map {

	unsigned int *mq_map;

	unsigned int nr_queues;
@@ -90,23 +100,45 @@ enum hctx_type { 
	HCTX_MAX_TYPES,

};



struct blk_mq_tag_set {

	/*

	 * map[] holds ctx -> hctx mappings, one map exists for each type

	 * that the driver wishes to support. There are no restrictions

	 * on maps being of the same size, and it's perfectly legal to

	 * share maps between types.

/**

 * struct blk_mq_tag_set - tag set that can be shared between request queues

 * @map:	   One or more ctx -> hctx mappings. One map exists for each

 *		   hardware queue type (enum hctx_type) that the driver wishes

 *		   to support. There are no restrictions on maps being of the

 *		   same size, and it's perfectly legal to share maps between

 *		   types.

 * @nr_maps:	   Number of elements in the @map array. A number in the range

 *		   [1, HCTX_MAX_TYPES].

 * @ops:	   Pointers to functions that implement block driver behavior.

 * @nr_hw_queues:  Number of hardware queues supported by the block driver that

 *		   owns this data structure.

 * @queue_depth:   Number of tags per hardware queue, reserved tags included.

 * @reserved_tags: Number of tags to set aside for BLK_MQ_REQ_RESERVED tag

 *		   allocations.

 * @cmd_size:	   Number of additional bytes to allocate per request. The block

 *		   driver owns these additional bytes.

 * @numa_node:	   NUMA node the storage adapter has been connected to.

 * @timeout:	   Request processing timeout in jiffies.

 * @flags:	   Zero or more BLK_MQ_F_* flags.

 * @driver_data:   Pointer to data owned by the block driver that created this

 *		   tag set.

 * @tags:	   Tag sets. One tag set per hardware queue. Has @nr_hw_queues

 *		   elements.

 * @tag_list_lock: Serializes tag_list accesses.

 * @tag_list:	   List of the request queues that use this tag set. See also

 *		   request_queue.tag_set_list.

 */

struct blk_mq_tag_set {

	struct blk_mq_queue_map	map[HCTX_MAX_TYPES];

	unsigned int		nr_maps;	/* nr entries in map[] */

	unsigned int		nr_maps;

	const struct blk_mq_ops	*ops;

	unsigned int		nr_hw_queues;	/* nr hw queues across maps */

	unsigned int		queue_depth;	/* max hw supported */

	unsigned int		nr_hw_queues;

	unsigned int		queue_depth;

	unsigned int		reserved_tags;

	unsigned int		cmd_size;	/* per-request extra data */

	unsigned int		cmd_size;

	int			numa_node;

	unsigned int		timeout;

	unsigned int		flags;		/* BLK_MQ_F_* */

	unsigned int		flags;

	void			*driver_data;



	struct blk_mq_tags	**tags;