Re: [PATCH net] netpoll: run NAPI poll in softirq context to avoid rq->lock self-deadlock

[Jakub Kicinski]

On Wed, 17 Jun 2026 07:56:50 -0700 Breno Leitao wrote:
> As far as I can tell, there isn't a network driver today whose transmit
> path is completely lockless, so, even if we make netpoll lockless.
> 
> It's unlikely any NIC will ever achieve this, given that NIC TX
> fundamentally relies on a shared DMA ring and doorbell register, which
> inherently cannot be made lockless.

The lock which protects the queue is maintained by the stack,
and we trylock it. Maybe I lost the thread but if you're saying
that writes to netconsole are impossible from arbitrary context,
that is _not_ true, AFAIU. We can queue a packet and kick off 
the transfer on well-behaved drivers.

Main problem is the opportunistic freeing up of the queue space.
If we could avoid that in atomic context I think we'd be good.