From: Simon Horman <horms@kernel.org>
To: Tariq Toukan <tariqt@nvidia.com>
Cc: Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Saeed Mahameed <saeedm@nvidia.com>,
Leon Romanovsky <leon@kernel.org>, Mark Bloch <mbloch@nvidia.com>,
netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
linux-kernel@vger.kernel.org, Gal Pressman <gal@nvidia.com>,
Dragos Tatulea <dtatulea@nvidia.com>
Subject: Re: [PATCH net V2 2/3] net/mlx5e: SHAMPO, Fix skb size check for 64K pages
Date: Wed, 5 Nov 2025 10:04:05 +0000 [thread overview]
Message-ID: <aQshFdIQ4uZBj7XI@horms.kernel.org> (raw)
In-Reply-To: <1762238915-1027590-3-git-send-email-tariqt@nvidia.com>
On Tue, Nov 04, 2025 at 08:48:34AM +0200, Tariq Toukan wrote:
> From: Dragos Tatulea <dtatulea@nvidia.com>
>
> 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>
next prev parent reply other threads:[~2025-11-05 10:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-04 6:48 [PATCH net V2 0/3] net/mlx5e: SHAMPO fixes for 64KB page size Tariq Toukan
2025-11-04 6:48 ` [PATCH net V2 1/3] net/mlx5e: SHAMPO, Fix header mapping for 64K pages Tariq Toukan
2025-11-05 10:03 ` Simon Horman
2025-11-04 6:48 ` [PATCH net V2 2/3] net/mlx5e: SHAMPO, Fix skb size check " Tariq Toukan
2025-11-05 10:04 ` Simon Horman [this message]
2025-11-04 6:48 ` [PATCH net V2 3/3] net/mlx5e: SHAMPO, Fix header formulas for higher MTUs and " Tariq Toukan
2025-11-05 10:04 ` Simon Horman
2025-11-06 2:00 ` [PATCH net V2 0/3] net/mlx5e: SHAMPO fixes for 64KB page size patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aQshFdIQ4uZBj7XI@horms.kernel.org \
--to=horms@kernel.org \
--cc=andrew+netdev@lunn.ch \
--cc=davem@davemloft.net \
--cc=dtatulea@nvidia.com \
--cc=edumazet@google.com \
--cc=gal@nvidia.com \
--cc=kuba@kernel.org \
--cc=leon@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rdma@vger.kernel.org \
--cc=mbloch@nvidia.com \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=saeedm@nvidia.com \
--cc=tariqt@nvidia.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).