Re: [PATCH 06/16] ia64: fix up obsolete cpu function usage.

From: Rusty Russell
Date: Thu May 28 2015 - 00:13:11 EST


Tony Luck <tony.luck@xxxxxxxxx> writes:
> On Tue, May 26, 2015 at 6:18 PM, Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote:
>
>> cpumask_test_cpu() doesn't take volatile, unlike the obsoleted
>> cpu_isset. The only place ia64 really cares is the spin waiting for a
>> bit; udelay() is probably a barrier but insert rmb() to be sure.
>
> Good to be sure ... but cpumask_test_cpu() simply calls test_bit() ...
> and 2 out of 3 versions of that function throw "volatile" back into the
> mix: :-)

Yep, volatile is hard to remove. But that seems like an argument for
removing the last user, not changing the interface...

The theory is that we're eschewing volatile, or so I thought.

Cheers,
Rusty.

> Global definition: test_bit
>
> File Line
> 0 include/asm/bitops.h 334 test_bit (int nr, const volatile
> void *addr)
> 1 asm-generic/bitops/non-atomic.h 103 static inline int test_bit(int
> nr, const volatile unsigned long *addr)
> 2 asm-generic/bitops/atomic.h 16 static __always_inline int
> test_bit(unsigned int nr, const unsigned long *addr)
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