linux-kernel - Re: [PATCH net-next V2] eth: fbnic: Configure RDE settings for pause frame

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <825c2171-1f35-4ded-b049-edb52323238b@lunn.ch>
Date: Sat, 15 Nov 2025 21:21:53 +0100
From: Andrew Lunn <andrew@...n.ch>
To: Mohsin Bashir <mohsin.bashr@...il.com>
Cc: netdev@...r.kernel.org, alexanderduyck@...com, almasrymina@...gle.com,
	andrew+netdev@...n.ch, davem@...emloft.net, edumazet@...gle.com,
	horms@...nel.org, kernel-team@...a.com, kuba@...nel.org,
	linux-kernel@...r.kernel.org, linux@...linux.org.uk,
	pabeni@...hat.com, rmk+kernel@...linux.org.uk
Subject: Re: [PATCH net-next V2] eth: fbnic: Configure RDE settings for pause
 frame

On Thu, Nov 13, 2025 at 03:26:10PM -0800, Mohsin Bashir wrote:
> fbnic supports pause frames. When pause frames are enabled presumably
> user expects lossless operation from the NIC. Make sure we configure
> RDE (Rx DMA Engine) to DROP_NEVER mode to avoid discards due to delays
> in fetching Rx descriptors from the host.
> 
> While at it enable DROP_NEVER when NIC only has a single queue
> configured. In this case the NIC acts as a FIFO so there's no risk
> of head-of-line blocking other queues by making RDE wait. If pause
> is disabled this just moves the packet loss from the DMA engine to
> the Rx buffer.
> 
> Remove redundant call to fbnic_config_drop_mode_rcq(), introduced by
> commit 0cb4c0a13723 ("eth: fbnic: Implement Rx queue
> alloc/start/stop/free"). This call does not add value as
> fbnic_enable_rcq(), which is called immediately afterward, already
> handles this.
> 
> Although we do not support autoneg at this time, preserve tx_pause in
> .mac_link_up instead of fbnic_phylink_get_pauseparam()
> 
> Signed-off-by: Mohsin Bashir <mohsin.bashr@...il.com>

Reviewed-by: Andrew Lunn <andrew@...n.ch>

    Andrew