net: mvneta: fix error path for building skb

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 <[email protected]> Acked-by: Simon Guinot <[email protected]> Cc: <[email protected]> # v4.2+ Fixes a84e328 ("net: mvneta: fix refilling for Rx DMA buffers") Signed-off-by: David S. Miller <[email protected]>
jledet · Dec 3, 2015 · 26c17a1 · 26c17a1
1 parent dc1aadf
commit 26c17a1
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
@@ -1580,12 +1580,16 @@ 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;