Patch "dmaengine: at_xdmac: clean used descriptor" has been added to the 4.2-stable tree

Patch "dmaengine: at_xdmac: clean used descriptor" has been added to the 4.2-stable tree

[gregkh]

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

    dmaengine: at_xdmac: clean used descriptor

to the 4.2-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-at_xdmac-clean-used-descriptor.patch
and it can be found in the queue-4.2 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 0be2136b67067617b36c70e525d7534108361e36 Mon Sep 17 00:00:00 2001
From: Ludovic Desroches <ludovic.desroches@atmel.com>
Date: Tue, 15 Sep 2015 15:39:11 +0200
Subject: dmaengine: at_xdmac: clean used descriptor

From: Ludovic Desroches <ludovic.desroches@atmel.com>

commit 0be2136b67067617b36c70e525d7534108361e36 upstream.

When putting back a descriptor to the free descs list, some fields are
not set to 0, it can cause bugs if someone uses it without having this
in mind.
Descriptor are not put back one by one so it is easier to clean
descriptors when we request them.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/dma/at_xdmac.c |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -455,6 +455,15 @@ static struct at_xdmac_desc *at_xdmac_al
 	return desc;
 }
 
+void at_xdmac_init_used_desc(struct at_xdmac_desc *desc)
+{
+	memset(&desc->lld, 0, sizeof(desc->lld));
+	INIT_LIST_HEAD(&desc->descs_list);
+	desc->direction = DMA_TRANS_NONE;
+	desc->xfer_size = 0;
+	desc->active_xfer = false;
+}
+
 /* Call must be protected by lock. */
 static struct at_xdmac_desc *at_xdmac_get_desc(struct at_xdmac_chan *atchan)
 {
@@ -466,7 +475,7 @@ static struct at_xdmac_desc *at_xdmac_ge
 		desc = list_first_entry(&atchan->free_descs_list,
 					struct at_xdmac_desc, desc_node);
 		list_del(&desc->desc_node);
-		desc->active_xfer = false;
+		at_xdmac_init_used_desc(desc);
 	}
 
 	return desc;


Patches currently in stable-queue which might be from ludovic.desroches@atmel.com are

queue-4.2/dmaengine-at_xdmac-clean-used-descriptor.patch
queue-4.2/dmaengine-at_xdmac-change-block-increment-addressing-mode.patch
queue-4.2/dmaengine-at_xdmac-fix-bug-in-prep_dma_cyclic.patch