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[157.230.128.187]) by smtp.gmail.com with ESMTPSA id o1sm3185397pjf.17.2020.06.23.15.03.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 Jun 2020 15:03:13 -0700 (PDT) Received: by 42.do-not-panic.com (Postfix, from userid 1000) id D885E418C0; Tue, 23 Jun 2020 22:03:12 +0000 (UTC) From: Luis Chamberlain 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 Subject: [PATCH 1/2] block: add initial kdoc over the request_queue Date: Tue, 23 Jun 2020 22:03:10 +0000 Message-Id: <20200623220311.8033-2-mcgrof@kernel.org> X-Mailer: git-send-email 2.23.0.rc1 In-Reply-To: <20200623220311.8033-1-mcgrof@kernel.org> References: <20200623220311.8033-1-mcgrof@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.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 Signed-off-by: Luis Chamberlain --- 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