[Intel-wired-lan] [PATCH iwl-net v1 0/2] Rework ice Tx checksum

[Michal Swiatkowski]

Hi,

Jakub find the problem with how ice handles Tx checksum offload [1].

The issue is that IP_CSUM/IPV6_CSUM should support only basic packet
types. Kernel assumes that if there are extensions headers and there is
no HW_CSUM software fallback should be applied. Here is a patch that
introduced that [2].

However, software fallback can't be applied when TSO offload happens.
That is the situation that this patchset is fixing.

When TSO is enabled and IP_CSUM/IPV6_CSUM is on, kernel is assuming
hardware will be able to calculate the checksum, but later on the
extension headers are checked and if there is no HW_CSUM the
skb_bad_offload() is called.

Following the documentation ice driver is capable of HW_CSUM support, so
switch from IP_CSUM/IPV6_CSUM to HW_CSUM. Other Intel drivers (even
previous like i40e, ixgbe) also supports HW_CSUM.

The HW_CSUM was used to indicate that GCS (Intel name for checksumming
offload using additional descriptor) is support, which is variation of
HW_CSUM. Even without GCS th HW_CSUM is supported. First patch is
switching to use custom Tx ring flags to allow HW_CSUM usage.

[1] https://lore.kernel.org/netdev/20260310150557.1138437-1-jramaseu@redhat.com/
[2] https://lore.kernel.org/all/5fbeecfc311ea182aa1d1c771725ab8b4cac515e.1729778144.git.benoit.monin@gmx.fr/

Michal Swiatkowski (2):
  ice: always do GCS if hardware supports it
  ice: use NETIF_F_HW_CSUM instead of IP/IPV6

 drivers/net/ethernet/intel/ice/ice_lib.c  |  4 ++++
 drivers/net/ethernet/intel/ice/ice_main.c | 21 +--------------------
 drivers/net/ethernet/intel/ice/ice_txrx.c |  2 +-
 drivers/net/ethernet/intel/ice/ice_txrx.h |  1 +
 4 files changed, 7 insertions(+), 21 deletions(-)

-- 
2.49.0