Patch "dmaengine: mv_xor_v2: properly handle wrapping in the array of HW descriptors" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

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

    dmaengine: mv_xor_v2: properly handle wrapping in the array of HW descriptors

to the 4.9-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:
     dmaengine-mv_xor_v2-properly-handle-wrapping-in-the-array-of-hw-descriptors.patch
and it can be found in the queue-4.9 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 2aab4e18152cd30cb5d2f4c27629fc8a04aed979 Mon Sep 17 00:00:00 2001
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Date: Fri, 5 May 2017 11:57:45 +0200
Subject: dmaengine: mv_xor_v2: properly handle wrapping in the array of HW descriptors

From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

commit 2aab4e18152cd30cb5d2f4c27629fc8a04aed979 upstream.

mv_xor_v2_tasklet() is looping over completed HW descriptors. Before the
loop, it initializes 'next_pending_hw_desc' to the first HW descriptor
to handle, and then the loop simply increments this point, without
taking care of wrapping when we reach the last HW descriptor. The
'pending_ptr' index was being wrapped back to 0 at the end, but it
wasn't used in each iteration of the loop to calculate
next_pending_hw_desc.

This commit fixes that, and makes next_pending_hw_desc a variable local
to the loop itself.

Fixes: 19a340b1a820 ("dmaengine: mv_xor_v2: new driver")
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/dma/mv_xor_v2.c |   14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

--- a/drivers/dma/mv_xor_v2.c
+++ b/drivers/dma/mv_xor_v2.c
@@ -560,7 +560,6 @@ static void mv_xor_v2_tasklet(unsigned l
 {
 	struct mv_xor_v2_device *xor_dev = (struct mv_xor_v2_device *) data;
 	int pending_ptr, num_of_pending, i;
-	struct mv_xor_v2_descriptor *next_pending_hw_desc = NULL;
 	struct mv_xor_v2_sw_desc *next_pending_sw_desc = NULL;
 
 	dev_dbg(xor_dev->dmadev.dev, "%s %d\n", __func__, __LINE__);
@@ -568,17 +567,10 @@ static void mv_xor_v2_tasklet(unsigned l
 	/* get the pending descriptors parameters */
 	num_of_pending = mv_xor_v2_get_pending_params(xor_dev, &pending_ptr);
 
-	/* next HW descriptor */
-	next_pending_hw_desc = xor_dev->hw_desq_virt + pending_ptr;
-
 	/* loop over free descriptors */
 	for (i = 0; i < num_of_pending; i++) {
-
-		if (pending_ptr > MV_XOR_V2_DESC_NUM)
-			pending_ptr = 0;
-
-		if (next_pending_sw_desc != NULL)
-			next_pending_hw_desc++;
+		struct mv_xor_v2_descriptor *next_pending_hw_desc =
+			xor_dev->hw_desq_virt + pending_ptr;
 
 		/* get the SW descriptor related to the HW descriptor */
 		next_pending_sw_desc =
@@ -614,6 +606,8 @@ static void mv_xor_v2_tasklet(unsigned l
 
 		/* increment the next descriptor */
 		pending_ptr++;
+		if (pending_ptr >= MV_XOR_V2_DESC_NUM)
+			pending_ptr = 0;
 	}
 
 	if (num_of_pending != 0) {


Patches currently in stable-queue which might be from thomas.petazzoni@free-electrons.com are

queue-4.9/dmaengine-mv_xor_v2-properly-handle-wrapping-in-the-array-of-hw-descriptors.patch
queue-4.9/dmaengine-mv_xor_v2-enable-xor-engine-after-its-configuration.patch
queue-4.9/dmaengine-mv_xor_v2-set-dma-mask-to-40-bits.patch
queue-4.9/dmaengine-mv_xor_v2-do-not-use-descriptors-not-acked-by-async_tx.patch
queue-4.9/dmaengine-mv_xor_v2-handle-mv_xor_v2_prep_sw_desc-error-properly.patch
queue-4.9/dmaengine-mv_xor_v2-remove-interrupt-coalescing.patch
queue-4.9/dmaengine-mv_xor_v2-fix-tx_submit-implementation.patch