Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCH] net: fec: fix regression on i.MX28 introduced by rx_copybreak support | Date | Wed, 8 Oct 2014 08:54:58 +0000 |
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From: Sergei Shtylyov > On 10/07/2014 05:19 PM, Lothar Wamann 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 Wamann <LW@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...
Hmmm... in that case you may not want the compiler to convert the bit value to a 'bool' at all.
Passing 'id_entry->driver_data' through (that doesn't look like a field name for 'quirk flags) would generate better code.
Even better would be to reference the flag directly from 'ndev'. A pointer indirection for the test if probably faster then passing another argument.
David
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