Messages in this thread | | | Date | Fri, 17 Dec 2021 10:00:52 +0100 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH 5/5] random: Defer processing of randomness on PREEMPT_RT. |
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On 2021-12-17 13:23:38 [+1100], Herbert Xu wrote: > Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote: > > > > Even the IOCTL path must spin with disabled interrupts to avoid dead > > locks. Therefore it makes no sense if attempt acquire the lock from > > process or IRQ context. Something like > > while (!raw_spin_trylock_irqsave()) > > cpu_relax() > > What about the TCP socket locking model? > > IOW, the user-space slow path will add itself to a backlog queue > during contention, and the interrupt fast path will schedule work > to process any user-space backlog on exit.
I'm sorry, I can't connect the dots here. I was trying to explain that for the lock in question it is not possible to spin-wait without disabling interrupts first.
> Cheers,
Sebastian
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