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

PATCH [email protected] 1 participant 1 message Oct 13, 2015

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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 <[email protected]> know about it.

Quoted 1 line

From 0be2136b67067617b36c70e525d7534108361e36 Mon Sep 17 00:00:00 2001

From: Ludovic Desroches <[email protected]>
Date: Tue, 15 Sep 2015 15:39:11 +0200
Subject: dmaengine: at_xdmac: clean used descriptor

From: Ludovic Desroches <[email protected]>

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.

---
 drivers/dma/at_xdmac.c |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)
drivers/dma/at_xdmac.c +10 -1
@@ -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 [email protected] 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