[PATCH 3.16.y-ckt 032/104] net: mvneta: fix DMA buffer unmapping in mvneta_rx()

From: Luis Henriques
Date: Mon Oct 26 2015 - 10:15:10 EST

3.16.7-ckt19 -stable review patch. If anyone has any objections, please let me know.


From: Simon Guinot <simon.guinot@xxxxxxxxxxxx>

commit daf158d0d544cec80b7b30deff8cfc59a6e17610 upstream.

This patch fixes a regression introduced by the commit a84e32894191
("net: mvneta: fix refilling for Rx DMA buffers"). Due to this commit
the newly allocated Rx buffers are DMA-unmapped in place of those passed
to the networking stack. Obviously, this causes data corruptions.

This patch fixes the issue by ensuring that the right Rx buffers are

Reported-by: Oren Laskin <oren@xxxxxxxxxx>
Signed-off-by: Simon Guinot <simon.guinot@xxxxxxxxxxxx>
Fixes: a84e32894191 ("net: mvneta: fix refilling for Rx DMA buffers")
Tested-by: Oren Laskin <oren@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
drivers/net/ethernet/marvell/mvneta.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 109908574224..03ab691ad683 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -1450,6 +1450,7 @@ static int mvneta_rx(struct mvneta_port *pp, int rx_todo,
struct mvneta_rx_desc *rx_desc = mvneta_rxq_next_desc_get(rxq);
struct sk_buff *skb;
unsigned char *data;
+ dma_addr_t phys_addr;
u32 rx_status;
int rx_bytes, err;

@@ -1457,6 +1458,7 @@ static int mvneta_rx(struct mvneta_port *pp, int rx_todo,
rx_status = rx_desc->status;
rx_bytes = rx_desc->data_size - (ETH_FCS_LEN + MVNETA_MH_SIZE);
data = (unsigned char *)rx_desc->buf_cookie;
+ phys_addr = rx_desc->buf_phys_addr;

if (!mvneta_rxq_desc_is_first_last(rx_status) ||
(rx_status & MVNETA_RXD_ERR_SUMMARY)) {
@@ -1505,7 +1507,7 @@ static int mvneta_rx(struct mvneta_port *pp, int rx_todo,
if (!skb)
goto err_drop_frame;

- dma_unmap_single(dev->dev.parent, rx_desc->buf_phys_addr,
+ dma_unmap_single(dev->dev.parent, phys_addr,

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