Hello.

On 10/07/2014 05:19 PM, Lothar Waßmann wrote:

commit 1b7bde6d659d ("net: fec: implement rx_copybreak to improve rx 
performance")
introduced a regression for i.MX28. The swap_buffer() function doing
the endian conversion of the received data on i.MX28 may access memory
beyond the actual packet size in the DMA buffer. fec_enet_copybreak()
does not copy those bytes, so that the last bytes of a packet may be
filled with invalid data after swapping.
This will likely lead to checksum errors on received packets.
E.g. when trying to mount an NFS rootfs:
UDP: bad checksum. From 192.168.1.225:111 to 192.168.100.73:44662 ulen 36

Do the byte swapping and copying to the new skb in one go if
necessary.

Signed-off-by: Lothar Waßmann <l...@karo-electronics.de>
---
  drivers/net/ethernet/freescale/fec_main.c |   25 +++++++++++++++++++++----
  1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/freescale/fec_main.c 
b/drivers/net/ethernet/freescale/fec_main.c
index 87975b5..eaaebad 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
[...]
@@ -1348,7 +1360,7 @@ fec_enet_new_rxbdp(struct net_device *ndev, struct 
bufdesc *bdp, struct sk_buff
  }

  static bool fec_enet_copybreak(struct net_device *ndev, struct sk_buff **skb,
-                              struct bufdesc *bdp, u32 length)
+                              struct bufdesc *bdp, u32 length, int swap)

   'bool swap' perhaps?

@@ -1393,6 +1408,7 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, 
u16 queue_id)
        u16     vlan_tag;
        int     index = 0;
        bool    is_copybreak;
+       bool need_swap = id_entry->driver_data & FEC_QUIRK_SWAP_FRAME;

   ... especially talking this into account...

WBR, Sergei

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