From 6a570814cd430fa5ef4f278e8046dcf12ee63f13 Mon Sep 17 00:00:00 2001 From: Dean Jenkins Date: Fri, 2 Oct 2015 14:29:08 +0100 Subject: [PATCH] asix: Continue processing URB if no RX netdev buffer Avoid a loss of synchronisation of the Ethernet Data header 32-bit word due to a failure to get a netdev socket buffer. The ASIX RX handling algorithm returned 0 upon a failure to get an allocation of a netdev socket buffer. This causes the URB processing to stop which potentially causes a loss of synchronisation with the Ethernet Data header 32-bit word. Therefore, subsequent processing of URBs may be rejected due to a loss of synchronisation. This may cause additional good Ethernet frames to be discarded along with outputting of synchronisation error messages. Implement a solution which checks whether a netdev socket buffer has been allocated before trying to copy the Ethernet frame into the netdev socket buffer. But continue to process the URB so that synchronisation is maintained. Therefore, only a single Ethernet frame is discarded when no netdev socket buffer is available. Signed-off-by: Dean Jenkins Signed-off-by: Mark Craske Signed-off-by: David S. Miller --- drivers/net/usb/asix_common.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-) diff --git a/drivers/net/usb/asix_common.c b/drivers/net/usb/asix_common.c index 1e4768debcc9..a186b0a12d50 100644 --- a/drivers/net/usb/asix_common.c +++ b/drivers/net/usb/asix_common.c @@ -74,12 +74,14 @@ int asix_rx_fixup_internal(struct usbnet *dev, struct sk_buff *skb, if (size != ((~rx->header >> 16) & 0x7ff)) { netdev_err(dev->net, "asix_rx_fixup() Data Header synchronisation was lost, remaining %d\n", rx->remaining); - kfree_skb(rx->ax_skb); - rx->ax_skb = NULL; - /* Discard the incomplete netdev Ethernet frame and - * assume the Data header is at the start of the current - * URB socket buffer. - */ + if (rx->ax_skb) { + kfree_skb(rx->ax_skb); + rx->ax_skb = NULL; + /* Discard the incomplete netdev Ethernet frame + * and assume the Data header is at the start of + * the current URB socket buffer. + */ + } rx->remaining = 0; } } @@ -121,9 +123,12 @@ int asix_rx_fixup_internal(struct usbnet *dev, struct sk_buff *skb, return 0; } + /* Sometimes may fail to get a netdev socket buffer but + * continue to process the URB socket buffer so that + * synchronisation of the Ethernet frame Data header + * word is maintained. + */ rx->ax_skb = netdev_alloc_skb_ip_align(dev->net, size); - if (!rx->ax_skb) - return 0; rx->remaining = size; } @@ -136,10 +141,12 @@ int asix_rx_fixup_internal(struct usbnet *dev, struct sk_buff *skb, rx->remaining = 0; } - data = skb_put(rx->ax_skb, copy_length); - memcpy(data, skb->data + offset, copy_length); - if (!rx->remaining) - usbnet_skb_return(dev, rx->ax_skb); + if (rx->ax_skb) { + data = skb_put(rx->ax_skb, copy_length); + memcpy(data, skb->data + offset, copy_length); + if (!rx->remaining) + usbnet_skb_return(dev, rx->ax_skb); + } offset += (copy_length + 1) & 0xfffe; } -- 2.39.5