Mark Rutland eccc2da8c0 atomics/treewide: Make atomic_fetch_add_unless() optional
Several architectures these have a near-identical implementation based
on atomic_read() and atomic_cmpxchg() which we can instead define in
<linux/atomic.h>, so let's do so, using something close to the existing
x86 implementation with try_cmpxchg().

Where an architecture provides its own atomic_fetch_add_unless(), it
must define a preprocessor symbol for it. The instrumented atomics are
updated accordingly.

Note that arch/arc's existing atomic_fetch_add_unless() had redundant
barriers, as these are already present in its atomic_cmpxchg()
implementation.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Palmer Dabbelt <palmer@sifive.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
Link: https://lore.kernel.org/lkml/20180621121321.4761-7-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21 14:22:33 +02:00
..
2016-01-12 20:46:58 +02:00
2016-07-24 06:33:29 +03:00
2018-06-15 18:10:01 -03:00
2015-08-17 07:33:39 +03:00
2014-01-15 00:28:11 +04:00
2017-06-05 16:53:10 -07:00
2018-02-11 09:18:12 -08:00
2018-04-19 13:28:51 +02:00
2017-12-16 22:37:12 -08:00
2017-12-16 22:37:10 -08:00
2017-12-16 22:37:10 -08:00
2018-06-07 12:45:58 -07:00
2017-12-16 22:37:12 -08:00
2018-01-02 03:25:41 -08:00
2018-01-29 16:40:28 -08:00
2017-12-16 22:37:09 -08:00