Re: [PATCH 1/9] lockdep: Use raw_cpu_*() for per-cpu variables

From: Steven Rostedt
Date: Thu Aug 20 2020 - 10:04:42 EST


On Thu, 20 Aug 2020 09:30:32 +0200
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> +++ b/include/linux/lockdep.h
> @@ -535,19 +535,27 @@ do { \
> DECLARE_PER_CPU(int, hardirqs_enabled);
> DECLARE_PER_CPU(int, hardirq_context);
>
> +/*
> + * The below lockdep_assert_*() macros se raw_cpu_read() to access the above

s/se/use/ ?

-- Steve

> + * per-cpu variables. This is required because this_cpu_read() will potentially
> + * call into preempt/irq-disable and that obviously isn't right. This is also
> + * correct because when IRQs are enabled, it doesn't matter if we accidentally
> + * read the value from our previous CPU.
> + */