net: mvneta: fix error path for building skb

commit 26c17a179f3f64f92de6e837c14279a6431a7ab6 upstream.

In the actual RX processing, there is same error path for both descriptor
ring refilling and building skb fails. This is not correct, because after
successful refill, the ring is already updated with newly allocated
buffer. Then, in case of build_skb() fail, hitherto code left the original
buffer unmapped.

This patch fixes above situation by swapping error check of skb build with
DMA-unmap of original buffer.

Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Acked-by: Simon Guinot <simon.guinot@sequanux.org>
Fixes a84e32894191 ("net: mvneta: fix refilling for Rx DMA buffers")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 8c6f307457d3b3a094445a70b251c0dee6e268fe..0e49244981d6e37b81386b0d5eba762b563d706d 100644 (file)
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -1533,12 +1533,16 @@ static int mvneta_rx(struct mvneta_port *pp, int rx_todo,
                }
 
                skb = build_skb(data, pp->frag_size > PAGE_SIZE ? 0 : pp->frag_size);
-               if (!skb)
-                       goto err_drop_frame;
 
+               /* After refill old buffer has to be unmapped regardless
+                * the skb is successfully built or not.
+                */
                dma_unmap_single(dev->dev.parent, phys_addr,
                                 MVNETA_RX_BUF_SIZE(pp->pkt_size), DMA_FROM_DEVICE);
 
+               if (!skb)
+                       goto err_drop_frame;
+
                rcvd_pkts++;
                rcvd_bytes += rx_bytes;