Re: [PATCH net-next v2 2/3] net: dev: Makes sure netif_rx() can be invoked in any context.

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 2022-02-10 10:13:30 [-0800], Jakub Kicinski wrote:
> > So we do netif_rx_backlog() with the bh disable+enable and
> > __netif_rx_backlog() without it and export both tree wide?
> 
> At a risk of confusing people about the API we could also name the
> "non-super-optimized" version netif_rx(), like you had in your patch.
> Grepping thru the drivers there's ~250 uses so maybe we don't wanna
> touch all that code. No strong preference, I just didn't expect to 
> see __netif_rx_backlog(), but either way works.

So let me keep the naming as-is, export __netif_rx() and update the
kernel doc with the bits about backlog.
After that if we are up to rename the function in ~250 drivers then I
should be simpler.

> > It would make it more obvious indeed. Could we add
> > 	WARN_ON_ONCE(!(hardirq_count() | softirq_count()))
> > to the shortcut to catch the "you did it wrong folks"? This costs me
> > about 2ns.
> 
> Modulo lockdep_..(), so we don't have to run this check on prod kernels?

I was worried a little about the corner cases but then lockdep is your
friend and you should test your code. Okay.

Sebastian