We start off with an initial description of the request_queue data structure, followed by describing the purpose of the debugfs_mutex debugfs_dir, and blk_trace.
Suggested-by: Bart Van Assche <[email protected]> Signed-off-by: Luis Chamberlain <[email protected]> --- include/linux/blkdev.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 70461b347169..ea319c2b0593 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -394,6 +394,26 @@ static inline int blkdev_zone_mgmt_ioctl(struct block_device *bdev, #endif /* CONFIG_BLK_DEV_ZONED */ +/** + * struct request_queue - block device driver request queue + * @debugfs_mutex: used to protect access to the @debugfs_dir + * @blk_trace: used by blktrace to keep track of setup / tracing + * @debugfs_dir: directory created to place debugfs information. This is always + * created for make_request and request-based block drivers upon + * initialization. blktrace requires for this directory to be created, + * and so it will be created on demand if its block driver type does not + * create it opon initialization. + * + * The request_queue is used to manage incoming block layer device driver + * requests. We have three main type of block driver types which end up making + * use of the request_queue: + * + * o make_request block drivers (multiqueue) + * o request-based block drivers + * o custom solutions such as scsi-generic + * + * All partitions share the same request_queue data structure. + */ struct request_queue { struct request *last_merge; struct elevator_queue *elevator; -- 2.26.2
