Patch "skd: Submit requests to firmware before triggering the doorbell" has been added to the 3.18-stable tree

[<gregkh@linuxfoundation.org>]

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

    skd: Submit requests to firmware before triggering the doorbell

to the 3.18-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:
     skd-submit-requests-to-firmware-before-triggering-the-doorbell.patch
and it can be found in the queue-3.18 subdirectory.

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


>From 5fbd545cd3fd311ea1d6e8be4cedddd0ee5684c7 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bart.vanassche@wdc.com>
Date: Thu, 17 Aug 2017 13:12:46 -0700
Subject: skd: Submit requests to firmware before triggering the doorbell

From: Bart Van Assche <bart.vanassche@wdc.com>

commit 5fbd545cd3fd311ea1d6e8be4cedddd0ee5684c7 upstream.

Ensure that the members of struct skd_msg_buf have been transferred
to the PCIe adapter before the doorbell is triggered. This patch
avoids that I/O fails sporadically and that the following error
message is reported:

(skd0:STM000196603:[0000:00:09.0]): Completion mismatch comp_id=0x0000 skreq=0x0400 new=0x0000

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/block/skd_main.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/block/skd_main.c
+++ b/drivers/block/skd_main.c
@@ -2214,6 +2214,9 @@ static void skd_send_fitmsg(struct skd_d
 		 */
 		qcmd |= FIT_QCMD_MSGSIZE_64;
 
+	/* Make sure skd_msg_buf is written before the doorbell is triggered. */
+	smp_wmb();
+
 	SKD_WRITEQ(skdev, qcmd, FIT_Q_COMMAND);
 
 }
@@ -2260,6 +2263,9 @@ static void skd_send_special_fitmsg(stru
 	qcmd = skspcl->mb_dma_address;
 	qcmd |= FIT_QCMD_QID_NORMAL + FIT_QCMD_MSGSIZE_128;
 
+	/* Make sure skd_msg_buf is written before the doorbell is triggered. */
+	smp_wmb();
+
 	SKD_WRITEQ(skdev, qcmd, FIT_Q_COMMAND);
 }
 


Patches currently in stable-queue which might be from bart.vanassche@wdc.com are

queue-3.18/skd-submit-requests-to-firmware-before-triggering-the-doorbell.patch
queue-3.18/block-relax-a-check-in-blk_start_queue.patch
queue-3.18/skd-avoid-that-module-unloading-triggers-a-use-after-free.patch