Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755948AbdLORUX (ORCPT ); Fri, 15 Dec 2017 12:20:23 -0500 Received: from mail-lf0-f68.google.com ([209.85.215.68]:38456 "EHLO mail-lf0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755755AbdLORUQ (ORCPT ); Fri, 15 Dec 2017 12:20:16 -0500 X-Google-Smtp-Source: ACJfBouoFmhsbeNvFPvLcuKNEWPVTNRlMpPakJelrchGWptXiHL1pHeBzRMfb+chKRRMRudClhQSwA== From: Alexander Kochetkov To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "David S. Miller" Cc: Florian Fainelli , Eric Dumazet , Alexander Kochetkov Subject: [PATCH] net: arc_emac: fix arc_emac_rx() error paths Date: Fri, 15 Dec 2017 20:20:06 +0300 Message-Id: <1513358406-32503-1-git-send-email-al.kochet@gmail.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3009 Lines: 91 arc_emac_rx() has some issues found by code review. In case netdev_alloc_skb_ip_align() or dma_map_single() failure rx fifo entry will not be returned to EMAC. In case dma_map_single() failure previously allocated skb became lost to driver. At the same time address of newly allocated skb will not be provided to EMAC. Signed-off-by: Alexander Kochetkov --- drivers/net/ethernet/arc/emac_main.c | 53 ++++++++++++++++++++-------------- 1 file changed, 31 insertions(+), 22 deletions(-) diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c index b2e0051..0ea57fe 100644 --- a/drivers/net/ethernet/arc/emac_main.c +++ b/drivers/net/ethernet/arc/emac_main.c @@ -212,39 +212,48 @@ static int arc_emac_rx(struct net_device *ndev, int budget) continue; } - pktlen = info & LEN_MASK; - stats->rx_packets++; - stats->rx_bytes += pktlen; - skb = rx_buff->skb; - skb_put(skb, pktlen); - skb->dev = ndev; - skb->protocol = eth_type_trans(skb, ndev); - - dma_unmap_single(&ndev->dev, dma_unmap_addr(rx_buff, addr), - dma_unmap_len(rx_buff, len), DMA_FROM_DEVICE); - - /* Prepare the BD for next cycle */ - rx_buff->skb = netdev_alloc_skb_ip_align(ndev, - EMAC_BUFFER_SIZE); - if (unlikely(!rx_buff->skb)) { + /* Prepare the BD for next cycle. netif_receive_skb() + * only if new skb was allocated and mapped to avoid holes + * in the RX fifo. + */ + skb = netdev_alloc_skb_ip_align(ndev, EMAC_BUFFER_SIZE); + if (unlikely(!skb)) { + if (net_ratelimit()) + netdev_err(ndev, "cannot allocate skb\n"); + /* Return ownership to EMAC */ + rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE); stats->rx_errors++; - /* Because receive_skb is below, increment rx_dropped */ stats->rx_dropped++; continue; } - /* receive_skb only if new skb was allocated to avoid holes */ - netif_receive_skb(skb); - - addr = dma_map_single(&ndev->dev, (void *)rx_buff->skb->data, + addr = dma_map_single(&ndev->dev, (void *)skb->data, EMAC_BUFFER_SIZE, DMA_FROM_DEVICE); if (dma_mapping_error(&ndev->dev, addr)) { if (net_ratelimit()) - netdev_err(ndev, "cannot dma map\n"); - dev_kfree_skb(rx_buff->skb); + netdev_err(ndev, "cannot map dma buffer\n"); + dev_kfree_skb(skb); + /* Return ownership to EMAC */ + rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE); stats->rx_errors++; + stats->rx_dropped++; continue; } + + /* unmap previosly mapped skb */ + dma_unmap_single(&ndev->dev, dma_unmap_addr(rx_buff, addr), + dma_unmap_len(rx_buff, len), DMA_FROM_DEVICE); + + pktlen = info & LEN_MASK; + stats->rx_packets++; + stats->rx_bytes += pktlen; + skb_put(rx_buff->skb, pktlen); + rx_buff->skb->dev = ndev; + rx_buff->skb->protocol = eth_type_trans(rx_buff->skb, ndev); + + netif_receive_skb(rx_buff->skb); + + rx_buff->skb = skb; dma_unmap_addr_set(rx_buff, addr, addr); dma_unmap_len_set(rx_buff, len, EMAC_BUFFER_SIZE); -- 1.7.9.5