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block: Document all members of blk_mq_tag_set and bkl_mq_queue_map

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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: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Bart Van Assche 2019-09-30 16:00:45 -07:00 committed by Jens Axboe
parent 73f1c77e65
commit 7a18312c73
1 changed files with 43 additions and 11 deletions
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54
include/linux/blk-mq.h
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@ -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 - 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 {
/*
* 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_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;