From: Bart Van Assche <bvanassche@acm.org>
Date: Mon, 30 Sep 2019 16:00:45 -0700
Subject: [PATCH] block: Document all members of blk_mq_tag_set and
Git-commit: 7a18312c739aeace7c8ea448d39a0313d5ad5d5d
Patch-mainline: v5.5-rc1
References: bsc#1175995,jsc#SLE-15608
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: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
include/linux/blk-mq.h | 54 ++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 43 insertions(+), 11 deletions(-)
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 0bf056de5cc3..a96b5cc957ab 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -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;
--
2.16.4