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| author | Mark Rutland <mark.rutland@arm.com> | 2018-06-21 13:13:09 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-06-21 14:22:33 +0200 |
| commit | eccc2da8c03f316bba202e15af2be4615f461900 (patch) | |
| tree | 1efd0bf1e8620a33ed58cd74cacc94ffc8cf111f /arch/arc | |
| parent | bef828204a1bc7a0fd3a24551c4265e9c2ab95ed (diff) | |
| download | linux-eccc2da8c03f316bba202e15af2be4615f461900.tar.gz linux-eccc2da8c03f316bba202e15af2be4615f461900.tar.bz2 linux-eccc2da8c03f316bba202e15af2be4615f461900.zip | |
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>
Diffstat (limited to 'arch/arc')
| -rw-r--r-- | arch/arc/include/asm/atomic.h | 28 |
1 files changed, 0 insertions, 28 deletions
diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h index 1406825b5e7d..60da80481c5d 100644 --- a/arch/arc/include/asm/atomic.h +++ b/arch/arc/include/asm/atomic.h @@ -308,34 +308,6 @@ ATOMIC_OPS(xor, ^=, CTOP_INST_AXOR_DI_R2_R2_R3) #undef ATOMIC_OP_RETURN #undef ATOMIC_OP -/** - * atomic_fetch_add_unless - add unless the number is a given value - * @v: pointer of type atomic_t - * @a: the amount to add to v... - * @u: ...unless v is equal to u. - * - * Atomically adds @a to @v, so long as it was not @u. - * Returns the old value of @v - */ -#define atomic_fetch_add_unless(v, a, u) \ -({ \ - int c, old; \ - \ - /* \ - * Explicit full memory barrier needed before/after as \ - * LLOCK/SCOND thmeselves don't provide any such semantics \ - */ \ - smp_mb(); \ - \ - c = atomic_read(v); \ - while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c)\ - c = old; \ - \ - smp_mb(); \ - \ - c; \ -}) - #define atomic_inc(v) atomic_add(1, v) #define atomic_dec(v) atomic_sub(1, v) |