Re: [net-next v6 5/9] net: napi: Add napi_config

[Joe Damato]

On Sat, Nov 30, 2024 at 12:45:01PM -0800, Jakub Kicinski wrote:
> On Wed, 27 Nov 2024 12:00:02 -0800 Joe Damato wrote:
> > CPU 0:
> > pcnet32_open
> >    lock(lp->lock)
> >      napi_enable
> >        napi_hash_add <- before this executes, CPU 1 proceeds
> >          lock(napi_hash_lock)
> > CPU 1:
> >   pcnet32_close
> >     napi_disable
> >       napi_hash_del
> >         lock(napi_hash_lock)
> >          < INTERRUPT >
> 
> How about making napi_hash_lock irq-safe ?
> It's a control path lock, it should be fine to disable irqs.

Ah, right. That should fix it.

I'll write a fixes against net and change the napi_hash_lock to use
spin_lock_irqsave and spin_lock_irqrestore and send shortly.

> >             pcnet32_interrupt
> >               lock(lp->lock)
>