From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH] net: fec: fix regression on i.MX28 introduced by rx_copybreak support Date: Tue, 07 Oct 2014 20:07:00 +0400 Message-ID: <54340FA4.509@cogentembedded.com> References: <1412687977-11742-1-git-send-email-LW@KARO-electronics.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "David S. Miller" , Russell King , Frank Li , Fabio Estevam , linux-kernel@vger.kernel.org To: =?UTF-8?B?TG90aGFyIFdhw59tYW5u?= , netdev@vger.kernel.org Return-path: In-Reply-To: <1412687977-11742-1-git-send-email-LW@KARO-electronics.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Hello. On 10/07/2014 05:19 PM, Lothar Wa=C3=9Fmann 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 memor= y > 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 ule= n 36 > Do the byte swapping and copying to the new skb in one go if > necessary. > Signed-off-by: Lothar Wa=C3=9Fmann > --- > 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, str= uct bufdesc *bdp, struct sk_buff > } > > static bool fec_enet_copybreak(struct net_device *ndev, struct sk_b= uff **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 =3D 0; > bool is_copybreak; > + bool need_swap =3D id_entry->driver_data & FEC_QUIRK_SWAP_FRAME; ... especially talking this into account... WBR, Sergei