Re: [PATCH] net: usb: lan78xx: Use phy_mac_interrupt() for interrupt handling

From: Jakub Kicinski
Date: Tue Oct 22 2019 - 13:18:03 EST

On Fri, 18 Oct 2019 15:15:32 +0200, Sebastian Andrzej Siewior wrote:
> On 2019-10-18 10:28:17 [+0200], Daniel Wagner wrote:
> > handle_simple_irq() expect interrupts to be disabled. The USB
> > framework is using threaded interrupts, which implies that interrupts
> > are re-enabled as soon as it has run.
> Without threading interrupts, this is invoked in pure softirq context
> since commit ed194d1367698 ("usb: core: remove local_irq_save() around
> ->complete() handler") where the local_irq_disable() has been removed.
> This is probably not a problem because the lock is never observed with
> in IRQ context.
> Wouldn't handle_nested_irq() work here instead of the simple thingy?

Daniel could you try this suggestion? Would it work?

I'm not sure we are at the stage yet where "doesn't work on -rt" is
sufficient reason to revert a working upstream patch. Please correct
me if I'm wrong.