Commit bacd8d80 authored by Dragos Tatulea's avatar Dragos Tatulea Committed by Jakub Kicinski
Browse files

net/mlx5e: SHAMPO, Fix skb size check for 64K pages 



mlx5e_hw_gro_skb_has_enough_space() uses a formula to check if there is
enough space in the skb frags to store more data. This formula is
incorrect for 64K page sizes and it triggers early GRO session
termination because the first fragment will blow up beyond
GRO_LEGACY_MAX_SIZE.

This patch adds a special case for page sizes >= GRO_LEGACY_MAX_SIZE
(64K) which uses the skb->len instead. Within this context,
the check is safe from fragment overflow because the hardware
will continuously fill the data up to the reservation size of 64K
and the driver will coalesce all data from the same page to the same
fragment. This means that the data will span one fragment or at most
two for such a large page size.

It is expected that the if statement will be optimized out as the
check is done with constants.

Fixes: 92552d3a ("net/mlx5e: HW_GRO cqe handler implementation")
Signed-off-by: default avatarDragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: default avatarTariq Toukan <tariqt@nvidia.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Link: https://patch.msgid.link/1762238915-1027590-3-git-send-email-tariqt@nvidia.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 665a7e13

drivers/net/ethernet/mellanox/mlx5/core/en_rx.c

+4 −1
Original line number Diff line number Diff line
@@ -2354,6 +2354,9 @@ mlx5e_hw_gro_skb_has_enough_space(struct sk_buff *skb, u16 data_bcnt) 
{

	int nr_frags = skb_shinfo(skb)->nr_frags;



	if (PAGE_SIZE >= GRO_LEGACY_MAX_SIZE)

		return skb->len + data_bcnt <= GRO_LEGACY_MAX_SIZE;

	else

		return PAGE_SIZE * nr_frags + data_bcnt <= GRO_LEGACY_MAX_SIZE;

}