6.6-stable review patch. If anyone has any objections, please let me know.
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From: Dragos Tatulea dtatulea@nvidia.com
[ Upstream commit bacd8d80181ebe34b599a39aa26bf73a44c91e55 ]
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: 92552d3abd32 ("net/mlx5e: HW_GRO cqe handler implementation") Signed-off-by: Dragos Tatulea dtatulea@nvidia.com Signed-off-by: Tariq Toukan tariqt@nvidia.com Reviewed-by: Simon Horman horms@kernel.org Link: https://patch.msgid.link/1762238915-1027590-3-git-send-email-tariqt@nvidia.c... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c index fcf7437174e18..1d586451900b8 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c @@ -2321,7 +2321,10 @@ mlx5e_hw_gro_skb_has_enough_space(struct sk_buff *skb, u16 data_bcnt) { int nr_frags = skb_shinfo(skb)->nr_frags;
- return PAGE_SIZE * nr_frags + data_bcnt <= GRO_LEGACY_MAX_SIZE; + 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; }
static void