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atomics/treewide: Make test ops optional

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Some of the atomics return the result of a test applied after the atomic
operation, and almost all architectures implement these as trivial
wrappers around the underlying atomic. Specifically:

 * <atomic>_inc_and_test(v)    is (<atomic>_inc_return(v)    == 0)
 * <atomic>_dec_and_test(v)    is (<atomic>_dec_return(v)    == 0)
 * <atomic>_sub_and_test(i, v) is (<atomic>_sub_return(i, v) == 0)
 * <atomic>_add_negative(i, v) is (<atomic>_add_return(i, v)  < 0)

Rather than have these definitions duplicated in all architectures, with
minor inconsistencies in formatting and documentation, let's make these
operations optional, with default fallbacks as above. Implementations
must now provide a preprocessor symbol.

The instrumented atomics are updated accordingly.

Both x86 and m68k have custom implementations, which are left as-is,
given preprocessor symbols to avoid being overridden.

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

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
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>
Link: https://lore.kernel.org/lkml/20180621121321.4761-16-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Mark Rutland
2018-06-21 13:13:18 +01:00
committed by Ingo Molnar
parent 356701329f
commit 18cc1814d4
24 changed files with 160 additions and 410 deletions
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46
arch/riscv/include/asm/atomic.h
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@@ -209,36 +209,6 @@ ATOMIC_OPS(xor, xor, i)
#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP_RETURN
/*
* The extra atomic operations that are constructed from one of the core
* AMO-based operations above (aside from sub, which is easier to fit above).
* These are required to perform a full barrier, but they're OK this way
* because atomic_*_return is also required to perform a full barrier.
*
*/
#define ATOMIC_OP(op, func_op, comp_op, I, c_type, prefix) \
static __always_inline \
bool atomic##prefix##_##op(c_type i, atomic##prefix##_t *v) \
{ \
return atomic##prefix##_##func_op##_return(i, v) comp_op I; \
}
#ifdef CONFIG_GENERIC_ATOMIC64
#define ATOMIC_OPS(op, func_op, comp_op, I) \
ATOMIC_OP(op, func_op, comp_op, I, int, )
#else
#define ATOMIC_OPS(op, func_op, comp_op, I) \
ATOMIC_OP(op, func_op, comp_op, I, int, ) \
ATOMIC_OP(op, func_op, comp_op, I, long, 64)
#endif
ATOMIC_OPS(add_and_test, add, ==, 0)
ATOMIC_OPS(sub_and_test, sub, ==, 0)
ATOMIC_OPS(add_negative, add, <, 0)
#undef ATOMIC_OP
#undef ATOMIC_OPS
#define ATOMIC_OP(op, func_op, I, c_type, prefix) \
static __always_inline \
void atomic##prefix##_##op(atomic##prefix##_t *v) \
@@ -315,22 +285,6 @@ ATOMIC_OPS(dec, add, +, -1)
#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP_RETURN
#define ATOMIC_OP(op, func_op, comp_op, I, prefix) \
static __always_inline \
bool atomic##prefix##_##op(atomic##prefix##_t *v) \
{ \
return atomic##prefix##_##func_op##_return(v) comp_op I; \
}
ATOMIC_OP(inc_and_test, inc, ==, 0, )
ATOMIC_OP(dec_and_test, dec, ==, 0, )
#ifndef CONFIG_GENERIC_ATOMIC64
ATOMIC_OP(inc_and_test, inc, ==, 0, 64)
ATOMIC_OP(dec_and_test, dec, ==, 0, 64)
#endif
#undef ATOMIC_OP
/* This is required to provide a full barrier on success. */
static __always_inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
{