Patch "net: mvpp2: fix DMA address calculation in mvpp2_txq_inc_put()" has been added to the 4.9-stable tree

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

net: mvpp2: fix DMA address calculation in mvpp2_txq_inc_put()

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:
net-mvpp2-fix-dma-address-calculation-in-mvpp2_txq_inc_put.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 <[email protected]> know about it.

From: Thomas Petazzoni <[email protected]>
Date: Tue, 21 Feb 2017 11:28:01 +0100
Subject: net: mvpp2: fix DMA address calculation in mvpp2_txq_inc_put()

From: Thomas Petazzoni <[email protected]>

commit 239a3b663647869330955ec59caac0100ef9b60a upstream.

When TX descriptors are filled in, the buffer DMA address is split between the tx_desc->buf_phys_addr field (high-order bits) and tx_desc->packet_offset field (5 low-order bits).

However, when we re-calculate the DMA address from the TX descriptor in mvpp2_txq_inc_put(), we do not take tx_desc->packet_offset into account. This means that when the DMA address is not aligned on a 32 bytes boundary, we end up calling dma_unmap_single() with a DMA address that was not the one returned by dma_map_single().

This inconsistency is detected by the kernel when DMA_API_DEBUG is enabled. We fix this problem by properly calculating the DMA address in mvpp2_txq_inc_put().

---
 drivers/net/ethernet/marvell/mvpp2.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -991,7 +991,7 @@ static void mvpp2_txq_inc_put(struct mvp
 		txq_pcpu->buffs + txq_pcpu->txq_put_index;
 	tx_buf->skb = skb;
 	tx_buf->size = tx_desc->data_size;
-	tx_buf->phys = tx_desc->buf_phys_addr;
+	tx_buf->phys = tx_desc->buf_phys_addr + tx_desc->packet_offset;
 	txq_pcpu->txq_put_index++;
 	if (txq_pcpu->txq_put_index == txq_pcpu->size)
 		txq_pcpu->txq_put_index = 0;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/net-mvpp2-fix-dma-address-calculation-in-mvpp2_txq_inc_put.patch