From: Simon Horman <horms@kernel.org>
To: Sankararaman Jayaraman <sankararaman.jayaraman@broadcom.com>
Cc: netdev@vger.kernel.org, ronak.doshi@broadcom.com,
bcm-kernel-feedback-list@broadcom.com, andrew+netdev@lunn.ch,
davem@davemloft.net, u9012063@gmail.com, kuba@kernel.org,
edumazet@google.com, pabeni@redhat.com, ast@kernel.org,
alexandr.lobakin@intel.com, alexanderduyck@fb.com,
bpf@vger.kernel.org, daniel@iogearbox.net, hawk@kernel.org,
john.fastabend@gmail.com
Subject: Re: [PATCH net] vmxnet3: Fix tx queue race condition with XDP
Date: Mon, 27 Jan 2025 17:01:10 +0000 [thread overview]
Message-ID: <20250127170110.GE5024@kernel.org> (raw)
In-Reply-To: <20250124090211.110328-1-sankararaman.jayaraman@broadcom.com>
On Fri, Jan 24, 2025 at 02:32:11PM +0530, Sankararaman Jayaraman wrote:
> If XDP traffic runs on a CPU which is greater than or equal to
> the number of the Tx queues of the NIC, then vmxnet3_xdp_get_tq()
> always picks up queue 0 for transmission as it uses reciprocal scale
> instead of simple modulo operation.
>
> vmxnet3_xdp_xmit() and vmxnet3_xdp_xmit_frame() use the above
> returned queue without any locking which can lead to race conditions
> when multiple XDP xmits run in parallel on different CPU's.
>
> This patch uses a simple module scheme when the current CPU equals or
> exceeds the number of Tx queues on the NIC. It also adds locking in
> vmxnet3_xdp_xmit() and vmxnet3_xdp_xmit_frame() functions.
>
> Fixes: 54f00cce1178 ("vmxnet3: Add XDP support.")
> Signed-off-by: Sankararaman Jayaraman <sankararaman.jayaraman@broadcom.com>
> Signed-off-by: Ronak Doshi <ronak.doshi@broadcom.com>
Reviewed-by: Simon Horman <horms@kernel.org>
next prev parent reply other threads:[~2025-01-27 17:01 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-24 9:02 [PATCH net] vmxnet3: Fix tx queue race condition with XDP Sankararaman Jayaraman
2025-01-24 16:45 ` William Tu
2025-01-27 17:01 ` Simon Horman [this message]
2025-01-27 22:36 ` Jakub Kicinski
2025-01-29 17:34 ` Sankararaman Jayaraman
2025-01-29 18:17 ` [PATCH net v2] " Sankararaman Jayaraman
2025-01-30 1:15 ` Jakub Kicinski
-- strict thread matches above, loose matches on Subject: below --
2025-01-08 3:48 [PATCH net] " Sankararaman Jayaraman
2025-01-08 18:13 ` Jakub Kicinski
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