[patch for 2.6.27? 4/5] forcedeth: fix checksum flag

[patch for 2.6.27? 4/5] forcedeth: fix checksum flag

[akpm]

From: Ayaz Abdulla <aabdulla@nvidia.com>

Fix the checksum feature advertised in device flags.  The hardware support
TCP/UDP over IPv4 and TCP/UDP over IPv6 (without IPv6 extension headers). 
However, the kernel feature flags do not distinguish IPv6 with/without
extension headers.

Therefore, the driver needs to use NETIF_F_IP_CSUM instead of
NETIF_F_HW_CSUM since the latter includes all IPv6 packets.

A future patch can be created to check for extension headers and perform
software checksum calculation.

Signed-off-by: Ayaz Abdulla <aabdulla@nvidia.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Manfred Spraul <manfred@colorfullife.com
Cc: <stable@kernel.org>		[2.6.25.x, 2.6.26.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/net/forcedeth.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff -puN drivers/net/forcedeth.c~forcedeth-fix-checksum-flag drivers/net/forcedeth.c
--- a/drivers/net/forcedeth.c~forcedeth-fix-checksum-flag
+++ a/drivers/net/forcedeth.c
@@ -5530,7 +5530,7 @@ static int __devinit nv_probe(struct pci
 	if (id->driver_data & DEV_HAS_CHECKSUM) {
 		np->rx_csum = 1;
 		np->txrxctl_bits |= NVREG_TXRXCTL_RXCHECK;
-		dev->features |= NETIF_F_HW_CSUM | NETIF_F_SG;
+		dev->features |= NETIF_F_IP_CSUM | NETIF_F_SG;
 		dev->features |= NETIF_F_TSO;
 	}
 
@@ -5843,7 +5843,7 @@ static int __devinit nv_probe(struct pci
 
 	dev_printk(KERN_INFO, &pci_dev->dev, "%s%s%s%s%s%s%s%s%s%sdesc-v%u\n",
 		   dev->features & NETIF_F_HIGHDMA ? "highdma " : "",
-		   dev->features & (NETIF_F_HW_CSUM | NETIF_F_SG) ?
+		   dev->features & (NETIF_F_IP_CSUM | NETIF_F_SG) ?
 		   	"csum " : "",
 		   dev->features & (NETIF_F_HW_VLAN_RX | NETIF_F_HW_VLAN_TX) ?
 		   	"vlan " : "",
_

Re: [patch for 2.6.27? 4/5] forcedeth: fix checksum flag

[Jeff Garzik]

akpm@linux-foundation.org wrote:
> From: Ayaz Abdulla <aabdulla@nvidia.com>
> 
> Fix the checksum feature advertised in device flags.  The hardware support
> TCP/UDP over IPv4 and TCP/UDP over IPv6 (without IPv6 extension headers). 
> However, the kernel feature flags do not distinguish IPv6 with/without
> extension headers.
> 
> Therefore, the driver needs to use NETIF_F_IP_CSUM instead of
> NETIF_F_HW_CSUM since the latter includes all IPv6 packets.
> 
> A future patch can be created to check for extension headers and perform
> software checksum calculation.
> 
> Signed-off-by: Ayaz Abdulla <aabdulla@nvidia.com>
> Cc: Jeff Garzik <jgarzik@pobox.com>
> Cc: Manfred Spraul <manfred@colorfullife.com
> Cc: <stable@kernel.org>		[2.6.25.x, 2.6.26.x]
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

applied, although for future reference, read the top of 
include/linux/skbuff.h, most notably:

  *          NOTE: Even if device supports only some protocols, but
  *          is able to produce some skb->csum, it MUST use COMPLETE,
  *          not UNNECESSARY.