[3.8.y.z extended stable] Patch "mtip32xx: Unmap the DMA segments before completing the IO request" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    mtip32xx: Unmap the DMA segments before completing the IO request

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.22.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 58e3dba21a78252c958268adeeb860dda2158726 Mon Sep 17 00:00:00 2001
From: Felipe Franciosi <felipe at paradoxo.org>
Date: Thu, 13 Mar 2014 14:34:21 +0000
Subject: mtip32xx: Unmap the DMA segments before completing the IO request

commit 368c89d7ac70f937c93cd6f3b65bcfdfb3ba794f upstream.

If the buffers are unmapped after completing a request, then stale data
might be in the request.

Signed-off-by: Felipe Franciosi <felipe at paradoxo.org>
Signed-off-by: Jens Axboe <axboe at fb.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/block/mtip32xx/mtip32xx.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index a838738..ca69cf9 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -602,6 +602,12 @@ static void mtip_timeout_function(unsigned long int data)
 			 */
 			writel(1 << bit, port->completed[group]);

+			/* Unmap the DMA scatter list entries */
+			dma_unmap_sg(&port->dd->pdev->dev,
+					command->sg,
+					command->scatter_ents,
+					command->direction);
+
 			/* Call the async completion callback. */
 			if (likely(command->async_callback))
 				command->async_callback(command->async_data,
@@ -609,12 +615,6 @@ static void mtip_timeout_function(unsigned long int data)
 			command->async_callback = NULL;
 			command->comp_func = NULL;

-			/* Unmap the DMA scatter list entries */
-			dma_unmap_sg(&port->dd->pdev->dev,
-					command->sg,
-					command->scatter_ents,
-					command->direction);
-
 			/*
 			 * Clear the allocated bit and active tag for the
 			 * command.
@@ -692,6 +692,12 @@ static void mtip_async_complete(struct mtip_port *port,
 			"Command tag %d failed due to TFE\n", tag);
 	}

+	/* Unmap the DMA scatter list entries */
+	dma_unmap_sg(&dd->pdev->dev,
+		command->sg,
+		command->scatter_ents,
+		command->direction);
+
 	/* Upper layer callback */
 	if (likely(command->async_callback))
 		command->async_callback(command->async_data, cb_status);
@@ -699,12 +705,6 @@ static void mtip_async_complete(struct mtip_port *port,
 	command->async_callback = NULL;
 	command->comp_func = NULL;

-	/* Unmap the DMA scatter list entries */
-	dma_unmap_sg(&dd->pdev->dev,
-		command->sg,
-		command->scatter_ents,
-		command->direction);
-
 	/* Clear the allocated and active bits for the command */
 	atomic_set(&port->commands[tag].active, 0);
 	release_slot(port, tag);
--
1.9.1