netdev - Re: [PATCH net-next 4/5] net/mlx5e: Don't drop RTNL during firmware flash

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Message-ID: <20250522090015.60147b61@kernel.org>
Date: Thu, 22 May 2025 09:00:15 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Tariq Toukan <tariqt@...dia.com>
Cc: "David S. Miller" <davem@...emloft.net>, Paolo Abeni
 <pabeni@...hat.com>, Eric Dumazet <edumazet@...gle.com>, "Andrew Lunn"
 <andrew+netdev@...n.ch>, Jason Gunthorpe <jgg@...pe.ca>, Leon Romanovsky
 <leon@...nel.org>, "Saeed Mahameed" <saeedm@...dia.com>, "Richard Cochran"
 <richardcochran@...il.com>, Alexei Starovoitov <ast@...nel.org>, Daniel
 Borkmann <daniel@...earbox.net>, Jesper Dangaard Brouer <hawk@...nel.org>,
 John Fastabend <john.fastabend@...il.com>, <linux-rdma@...r.kernel.org>,
 <linux-kernel@...r.kernel.org>, <netdev@...r.kernel.org>,
 <bpf@...r.kernel.org>, Moshe Shemesh <moshe@...dia.com>, Mark Bloch
 <mbloch@...dia.com>, Gal Pressman <gal@...dia.com>, Cosmin Ratiu
 <cratiu@...dia.com>
Subject: Re: [PATCH net-next 4/5] net/mlx5e: Don't drop RTNL during firmware
 flash

On Wed, 21 May 2025 15:09:01 +0300 Tariq Toukan wrote:
> However, the stack is moving towards netdev instance locking and
> dropping and reacquiring RTNL in the context of flashing introduces
> locking ordering issues: RTNL must be acquired before the netdev
> instance lock and released after it.
> 
> This patch therefore takes the simpler approach by no longer dropping
> and reacquiring the RTNL, as soon RTNL for ethtool will be removed,
> leaving only the instance lock to protect against races.

You didn't mention it so just in case someone tries to report this 
as a regression later - devlink has been the preferred way to flash
devices for 5+ years. It has much better UX with the progress
notifications, and already does per-instance locking.