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Commit 67b1684c authored by Thomas Petazzoni's avatar Thomas Petazzoni Committed by Greg Kroah-Hartman
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dmaengine: mv_xor_v2: properly handle wrapping in the array of HW descriptors 



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: 19a340b1 ("dmaengine: mv_xor_v2: new driver")
Signed-off-by: default avatarThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f08c84d4

drivers/dma/mv_xor_v2.c

+4 −10
Original line number Diff line number Diff line
@@ -560,7 +560,6 @@ static void mv_xor_v2_tasklet(unsigned long data) 
{

	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 long data) 
	/* 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 long data) 


		/* increment the next descriptor */

		pending_ptr++;

		if (pending_ptr >= MV_XOR_V2_DESC_NUM)

			pending_ptr = 0;

	}



	if (num_of_pending != 0) {