From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Horman Subject: [net PATCH v4] 8139cp: Add dma_mapping_error checking Date: Wed, 31 Jul 2013 09:03:56 -0400 Message-ID: <1375275836-22187-1-git-send-email-nhorman@tuxdriver.com> References: <1374516882-19131-1-git-send-email-nhorman@tuxdriver.com> Cc: Neil Horman , "David S. Miller" , Francois Romieu To: netdev@vger.kernel.org Return-path: Received: from charlotte.tuxdriver.com ([70.61.120.58]:51724 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751310Ab3GaNEc (ORCPT ); Wed, 31 Jul 2013 09:04:32 -0400 In-Reply-To: <1374516882-19131-1-git-send-email-nhorman@tuxdriver.com> Sender: netdev-owner@vger.kernel.org List-ID: Self explanitory dma_mapping_error addition to the 8139 driver, based on this: https://bugzilla.redhat.com/show_bug.cgi?id=947250 It showed several backtraces arising for dma_map_* usage without checking the return code on the mapping. Add the check and abort the rx/tx operation if its failed. Untested as I have no hardware and the reporter has wandered off, but seems pretty straightforward. Signed-off-by: Neil Horman CC: "David S. Miller" CC: Francois Romieu --- Change notes: v2) Added stats update for tx_dropped as per Francois Romieu v3) * Updated rx patch to handle dma errors properly. Francois had pointed out that I needed to increment the rx_dropped stat there, but the problem was a bit deeper. I actually had to move the dma_mapping and error check higher in the path, so that, in the event of a failure, we could drop the received skb, and reuse its existing mapping in the rx ring. this is in line with what happens if the skb allocation fails * Updated the tx path to have a common goto for mapping failures, so we only have one location to drop the skb * Moved the unwind code into a separate helper function, as per Francois suggestion. I though it would be alot of parameter passing and not very adventageous, but on second look I think its more readable. v4) * Fix rx/tx naming error. --- drivers/net/ethernet/realtek/8139cp.c | 48 ++++++++++++++++++++++++++++++++--- 1 file changed, 45 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/realtek/8139cp.c b/drivers/net/ethernet/realtek/8139cp.c index 0352345..887aebe 100644 --- a/drivers/net/ethernet/realtek/8139cp.c +++ b/drivers/net/ethernet/realtek/8139cp.c @@ -478,7 +478,7 @@ rx_status_loop: while (1) { u32 status, len; - dma_addr_t mapping; + dma_addr_t mapping, new_mapping; struct sk_buff *skb, *new_skb; struct cp_desc *desc; const unsigned buflen = cp->rx_buf_sz; @@ -520,6 +520,13 @@ rx_status_loop: goto rx_next; } + new_mapping = dma_map_single(&cp->pdev->dev, new_skb->data, buflen, + PCI_DMA_FROMDEVICE); + if (dma_mapping_error(&cp->pdev->dev, new_mapping)) { + dev->stats.rx_dropped++; + goto rx_next; + } + dma_unmap_single(&cp->pdev->dev, mapping, buflen, PCI_DMA_FROMDEVICE); @@ -531,12 +538,11 @@ rx_status_loop: skb_put(skb, len); - mapping = dma_map_single(&cp->pdev->dev, new_skb->data, buflen, - PCI_DMA_FROMDEVICE); cp->rx_skb[rx_tail] = new_skb; cp_rx_skb(cp, skb, desc); rx++; + mapping = new_mapping; rx_next: cp->rx_ring[rx_tail].opts2 = 0; @@ -716,6 +722,22 @@ static inline u32 cp_tx_vlan_tag(struct sk_buff *skb) TxVlanTag | swab16(vlan_tx_tag_get(skb)) : 0x00; } +static void unwind_tx_frag_mapping(struct cp_private *cp, struct sk_buff *skb, + int first, int entry_last) +{ + int frag, index; + struct cp_desc *txd; + skb_frag_t *this_frag; + for (frag = 0; frag+first < entry_last; frag++) { + index = first+frag; + cp->tx_skb[index] = NULL; + txd = &cp->tx_ring[index]; + this_frag = &skb_shinfo(skb)->frags[frag]; + dma_unmap_single(&cp->pdev->dev, le64_to_cpu(txd->addr), + skb_frag_size(this_frag), PCI_DMA_TODEVICE); + } +} + static netdev_tx_t cp_start_xmit (struct sk_buff *skb, struct net_device *dev) { @@ -749,6 +771,9 @@ static netdev_tx_t cp_start_xmit (struct sk_buff *skb, len = skb->len; mapping = dma_map_single(&cp->pdev->dev, skb->data, len, PCI_DMA_TODEVICE); + if (dma_mapping_error(&cp->pdev->dev, mapping)) + goto out_dma_error; + txd->opts2 = opts2; txd->addr = cpu_to_le64(mapping); wmb(); @@ -786,6 +811,9 @@ static netdev_tx_t cp_start_xmit (struct sk_buff *skb, first_len = skb_headlen(skb); first_mapping = dma_map_single(&cp->pdev->dev, skb->data, first_len, PCI_DMA_TODEVICE); + if (dma_mapping_error(&cp->pdev->dev, first_mapping)) + goto out_dma_error; + cp->tx_skb[entry] = skb; entry = NEXT_TX(entry); @@ -799,6 +827,11 @@ static netdev_tx_t cp_start_xmit (struct sk_buff *skb, mapping = dma_map_single(&cp->pdev->dev, skb_frag_address(this_frag), len, PCI_DMA_TODEVICE); + if (dma_mapping_error(&cp->pdev->dev, mapping)) { + unwind_tx_frag_mapping(cp, skb, first_entry, entry); + goto out_dma_error; + } + eor = (entry == (CP_TX_RING_SIZE - 1)) ? RingEnd : 0; ctrl = eor | len | DescOwn; @@ -859,11 +892,16 @@ static netdev_tx_t cp_start_xmit (struct sk_buff *skb, if (TX_BUFFS_AVAIL(cp) <= (MAX_SKB_FRAGS + 1)) netif_stop_queue(dev); +out_unlock: spin_unlock_irqrestore(&cp->lock, intr_flags); cpw8(TxPoll, NormalTxPoll); return NETDEV_TX_OK; +out_dma_error: + kfree_skb(skb); + cp->dev->stats.tx_dropped++; + goto out_unlock; } /* Set or clear the multicast filter for this adaptor. @@ -1054,6 +1092,10 @@ static int cp_refill_rx(struct cp_private *cp) mapping = dma_map_single(&cp->pdev->dev, skb->data, cp->rx_buf_sz, PCI_DMA_FROMDEVICE); + if (dma_mapping_error(&cp->pdev->dev, mapping)) { + kfree_skb(skb); + goto err_out; + } cp->rx_skb[i] = skb; cp->rx_ring[i].opts2 = 0; -- 1.8.1.4