From: Luis Chamberlain <mcgrof@kernel.org>
To: axboe@kernel.dk, damien.lemoal@wdc.com, bvanassche@acm.org,
ming.lei@redhat.com, martin.petersen@oracle.com,
satyat@google.com
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
Luis Chamberlain <mcgrof@kernel.org>
Subject: [PATCH 1/2] block: add initial kdoc over the request_queue
Date: Tue, 23 Jun 2020 22:03:10 +0000 [thread overview]
Message-ID: <20200623220311.8033-2-mcgrof@kernel.org> (raw)
In-Reply-To: <20200623220311.8033-1-mcgrof@kernel.org>
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 <bvanassche@acm.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
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
next prev parent reply other threads:[~2020-06-23 22:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 22:03 [PATCH 0/2] block: kdocify the request_queue Luis Chamberlain
2020-06-23 22:03 ` Luis Chamberlain [this message]
2020-06-24 0:33 ` [PATCH 1/2] block: add initial kdoc over " Damien Le Moal
2020-06-24 7:22 ` Johannes Thumshirn
2020-06-28 20:53 ` Bart Van Assche
2020-06-23 22:03 ` [PATCH 2/2] block: move request_queue member docs to kdoc Luis Chamberlain
2020-06-24 0:46 ` Damien Le Moal
2020-06-24 7:23 ` Johannes Thumshirn
2020-06-28 21:23 ` Bart Van Assche
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