[PATCH v4 7/8] lockdep: Change hardirq{s_enabled,_context} to per-cpu variables

[Peter Zijlstra]

On Tue, Jun 30, 2020 at 07:59:39AM +0200, Ahmed S. Darwish wrote:
> Peter Zijlstra wrote:
> 
> ...
> 
> > -#define lockdep_assert_irqs_disabled()	do {			\
> > -		WARN_ONCE(debug_locks && !current->lockdep_recursion &&	\
> > -			  current->hardirqs_enabled,			\
> > -			  "IRQs not disabled as expected\n");		\
> > -	} while (0)
> 
> ...
> 
> > +#define lockdep_assert_irqs_disabled()				\
> > +do {									\
> > +	WARN_ON_ONCE(debug_locks && this_cpu_read(hardirqs_enabled));	\
> > +} while (0)
> 
> I think it would be nice to keep the "IRQs not disabled as expected"
> message. It makes the lockdep splat much more readable.
> 
> This is similarly the case for the v3 lockdep preemption macros:
> 
>   https://lkml.kernel.org/r/20200630054452.3675847-5-a.darwish@linutronix.de
> 
> I did not add a message though to get in-sync with the IRQ macros above.

Hurmph.. the file:line output of a splat is usually all I look at, also
__WARN_printf() generates such atrocious crap code that try and not use
it.

I suppose I should do a __WARN_str() or something, but then people are
unlikely to want to use that, too much variation etc. :/

Cursed if you do, cursed if you don't.