From: Simon Horman <horms@kernel.org>
To: Stanislav Fomichev <sdf.kernel@gmail.com>
Cc: netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com,
kuba@kernel.org, pabeni@redhat.com, anthony.l.nguyen@intel.com,
przemyslaw.kitszel@intel.com, andrew+netdev@lunn.ch,
saeedm@nvidia.com, tariqt@nvidia.com, mbloch@nvidia.com,
maxime.chevallier@bootlin.com, mcoquelin.stm32@gmail.com,
alexandre.torgue@foss.st.com, aleksander.lobakin@intel.com,
magnus.karlsson@intel.com, maciej.fijalkowski@intel.com,
sdf@fomichev.me, ast@kernel.org, daniel@iogearbox.net,
hawk@kernel.org, john.fastabend@gmail.com, witu@nvidia.com,
martin.lau@kernel.org, yoong.siang.song@intel.com,
rohan.g.thomas@intel.com, intel-wired-lan@lists.osuosl.org,
linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
linux-stm32@st-md-mailman.stormreply.com,
linux-arm-kernel@lists.infradead.org, bpf@vger.kernel.org,
leon@kernel.org
Subject: Re: [Intel-wired-lan] [PATCH net v2 1/3] xsk: align TX metadata layout across ABIs
Date: Mon, 17 Aug 2026 11:17:20 +0100 [thread overview]
Message-ID: <20260817101720.GX265046@horms.kernel.org> (raw)
In-Reply-To: <20260813190800.222527-2-sdf@fomichev.me>
On Thu, Aug 13, 2026 at 12:07:58PM -0700, Stanislav Fomichev wrote:
> Add explicit padding before launch_time so xsk_tx_metadata has the same
> layout on 32-bit and 64-bit systems.
>
> On i386 and m68k, the old native 32-bit layout put launch_time at offset 12
> and had a natural size of 20 bytes. Using sizeof(struct xsk_tx_metadata) as
> tx_metadata_len was already rejected because the length must be a multiple
> of eight, so the straightforward use of the interface was broken on those
> ABIs. Userspace could still register a padded length of 24 bytes, though;
> mixing the old and new layouts then silently reads launch_time from the
> wrong offset and misprograms packet launch times. This intentionally
> replaces that incompatible layout while the interface is still new.
>
> Fixes: ca4419f15abd ("xsk: Add launch time hardware offload support to XDP Tx metadata")
> Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Simon Horman <horms@kernel.org>
next prev parent reply other threads:[~2026-08-17 10:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-13 19:07 [Intel-wired-lan] [PATCH net v2 0/3] xsk: pre-existing AF_XDP TX metadata fixes from Sashiko Stanislav Fomichev
2026-08-13 19:07 ` [Intel-wired-lan] [PATCH net v2 1/3] xsk: align TX metadata layout across ABIs Stanislav Fomichev
2026-08-17 10:17 ` Simon Horman [this message]
2026-08-17 12:59 ` Arnd Bergmann
2026-08-13 19:07 ` [Intel-wired-lan] [PATCH net v2 2/3] xsk: honor XDP_TX_METADATA in zero-copy path Stanislav Fomichev
2026-08-13 19:08 ` [Intel-wired-lan] [PATCH net v2 3/3] net: stmmac: skip queueMaxSDU check for AF_XDP Stanislav Fomichev
2026-08-17 10:17 ` Simon Horman
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