[dm-devel] Patch "scsi: implement .cleanup_rq callback" has been added to the 5.2-stable tree

[gregkh at linuxfoundation.org]

This is a note to let you know that I've just added the patch titled

    scsi: implement .cleanup_rq callback

to the 5.2-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     scsi-implement-.cleanup_rq-callback.patch
and it can be found in the queue-5.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable at vger.kernel.org> know about it.


>From b7e9e1fb7a9227be34ad4a5e778022c3164494cf Mon Sep 17 00:00:00 2001
From: Ming Lei <ming.lei at redhat.com>
Date: Thu, 25 Jul 2019 10:05:00 +0800
Subject: scsi: implement .cleanup_rq callback

From: Ming Lei <ming.lei at redhat.com>

commit b7e9e1fb7a9227be34ad4a5e778022c3164494cf upstream.

Implement .cleanup_rq() callback for freeing driver private part
of the request. Then we can avoid to leak this part if the request isn't
completed by SCSI, and freed by blk-mq or upper layer(such as dm-rq) finally.

Cc: Ewan D. Milne <emilne at redhat.com>
Cc: Bart Van Assche <bvanassche at acm.org>
Cc: Hannes Reinecke <hare at suse.com>
Cc: Christoph Hellwig <hch at lst.de>
Cc: Mike Snitzer <snitzer at redhat.com>
Cc: dm-devel at redhat.com
Cc: <stable at vger.kernel.org>
Fixes: 396eaf21ee17 ("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback")
Signed-off-by: Ming Lei <ming.lei at redhat.com>
Signed-off-by: Jens Axboe <axboe at kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>

---
 drivers/scsi/scsi_lib.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1073,6 +1073,18 @@ static void scsi_initialize_rq(struct re
 	cmd->retries = 0;
 }
 
+/*
+ * Only called when the request isn't completed by SCSI, and not freed by
+ * SCSI
+ */
+static void scsi_cleanup_rq(struct request *rq)
+{
+	if (rq->rq_flags & RQF_DONTPREP) {
+		scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
+		rq->rq_flags &= ~RQF_DONTPREP;
+	}
+}
+
 /* Add a command to the list used by the aacraid and dpt_i2o drivers */
 void scsi_add_cmd_to_list(struct scsi_cmnd *cmd)
 {
@@ -1800,6 +1812,7 @@ static const struct blk_mq_ops scsi_mq_o
 	.init_request	= scsi_mq_init_request,
 	.exit_request	= scsi_mq_exit_request,
 	.initialize_rq_fn = scsi_initialize_rq,
+	.cleanup_rq	= scsi_cleanup_rq,
 	.busy		= scsi_mq_lld_busy,
 	.map_queues	= scsi_map_queues,
 };


Patches currently in stable-queue which might be from ming.lei at redhat.com are

queue-5.2/scsi-implement-.cleanup_rq-callback.patch