FAILED: patch "[PATCH] scsi: implement .cleanup_rq callback" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b7e9e1fb7a9227be34ad4a5e778022c3164494cf Mon Sep 17 00:00:00 2001
From: Ming Lei <[email protected]>
Date: Thu, 25 Jul 2019 10:05:00 +0800
Subject: [PATCH] scsi: implement .cleanup_rq callback

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.

index 11e64b50497f..4e88d7e9cf9a 100644
@@ -1089,6 +1089,18 @@ static void scsi_initialize_rq(struct request *rq)
 	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)
 {

@@ -1821,6 +1833,7 @@ static const struct blk_mq_ops scsi_mq_ops = {
 	.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,
 };

I saw that it was also dropped from 5.3/5.2 for build errors. To resolve those I took 226b4fc75c78 ("blk-mq: add callback of .cleanup_rq") which is also tagged for stable.

For 4.19 there were some context changes due to the removal of the legacy IO code (6a23e05c2fe3c ("dm: remove legacy request-based IO path") et al).

--
Thanks,
Sasha

Ah, I missed that dependancy, thanks for fixing this all up.

greg k-h