Re: Can srcu_read_lock() be called from interrupt context?

From: Paul E. McKenney
Date: Tue Nov 03 2015 - 04:55:50 EST

On Mon, Nov 02, 2015 at 05:56:56PM -0800, Yunhong Jiang wrote:
> Hi, Paul
> I have a question to the srcu_read_lock(). Can it be invoked on
> interrupt context? According to
> it can only be
> called from process context, but according to
> seems it's ok
> from irq context only if it matches with the srcu_read_unlock. Can you
> please give some hints?

Adding Lai Jianshan for his thoughts.

I believe that srcu.h is correct, at least assuming that interrupts do
not nest too deeply. (If they were to nest four billion deep, then the
->seq[] counter could overflow, defeating the checks, but the CPU stack
would have overflowed long before.)

Lai, am I missing anything here?

Thanx, Paul

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