mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-06 19:07:52 +00:00
locking/atomic, arch/avr32: Implement atomic_fetch_{add,sub,and,or,xor}()
Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
parent
2efe95fe69
commit
1a6eafacd4
1 changed files with 51 additions and 5 deletions
|
@ -41,21 +41,51 @@ static inline int __atomic_##op##_return(int i, atomic_t *v) \
|
||||||
return result; \
|
return result; \
|
||||||
}
|
}
|
||||||
|
|
||||||
|
#define ATOMIC_FETCH_OP(op, asm_op, asm_con) \
|
||||||
|
static inline int __atomic_fetch_##op(int i, atomic_t *v) \
|
||||||
|
{ \
|
||||||
|
int result, val; \
|
||||||
|
\
|
||||||
|
asm volatile( \
|
||||||
|
"/* atomic_fetch_" #op " */\n" \
|
||||||
|
"1: ssrf 5\n" \
|
||||||
|
" ld.w %0, %3\n" \
|
||||||
|
" mov %1, %0\n" \
|
||||||
|
" " #asm_op " %1, %4\n" \
|
||||||
|
" stcond %2, %1\n" \
|
||||||
|
" brne 1b" \
|
||||||
|
: "=&r" (result), "=&r" (val), "=o" (v->counter) \
|
||||||
|
: "m" (v->counter), #asm_con (i) \
|
||||||
|
: "cc"); \
|
||||||
|
\
|
||||||
|
return result; \
|
||||||
|
}
|
||||||
|
|
||||||
ATOMIC_OP_RETURN(sub, sub, rKs21)
|
ATOMIC_OP_RETURN(sub, sub, rKs21)
|
||||||
ATOMIC_OP_RETURN(add, add, r)
|
ATOMIC_OP_RETURN(add, add, r)
|
||||||
|
ATOMIC_FETCH_OP (sub, sub, rKs21)
|
||||||
|
ATOMIC_FETCH_OP (add, add, r)
|
||||||
|
|
||||||
#define ATOMIC_OP(op, asm_op) \
|
#define atomic_fetch_or atomic_fetch_or
|
||||||
|
|
||||||
|
#define ATOMIC_OPS(op, asm_op) \
|
||||||
ATOMIC_OP_RETURN(op, asm_op, r) \
|
ATOMIC_OP_RETURN(op, asm_op, r) \
|
||||||
static inline void atomic_##op(int i, atomic_t *v) \
|
static inline void atomic_##op(int i, atomic_t *v) \
|
||||||
{ \
|
{ \
|
||||||
(void)__atomic_##op##_return(i, v); \
|
(void)__atomic_##op##_return(i, v); \
|
||||||
|
} \
|
||||||
|
ATOMIC_FETCH_OP(op, asm_op, r) \
|
||||||
|
static inline int atomic_fetch_##op(int i, atomic_t *v) \
|
||||||
|
{ \
|
||||||
|
return __atomic_fetch_##op(i, v); \
|
||||||
}
|
}
|
||||||
|
|
||||||
ATOMIC_OP(and, and)
|
ATOMIC_OPS(and, and)
|
||||||
ATOMIC_OP(or, or)
|
ATOMIC_OPS(or, or)
|
||||||
ATOMIC_OP(xor, eor)
|
ATOMIC_OPS(xor, eor)
|
||||||
|
|
||||||
#undef ATOMIC_OP
|
#undef ATOMIC_OPS
|
||||||
|
#undef ATOMIC_FETCH_OP
|
||||||
#undef ATOMIC_OP_RETURN
|
#undef ATOMIC_OP_RETURN
|
||||||
|
|
||||||
/*
|
/*
|
||||||
|
@ -87,6 +117,14 @@ static inline int atomic_add_return(int i, atomic_t *v)
|
||||||
return __atomic_add_return(i, v);
|
return __atomic_add_return(i, v);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
static inline int atomic_fetch_add(int i, atomic_t *v)
|
||||||
|
{
|
||||||
|
if (IS_21BIT_CONST(i))
|
||||||
|
return __atomic_fetch_sub(-i, v);
|
||||||
|
|
||||||
|
return __atomic_fetch_add(i, v);
|
||||||
|
}
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* atomic_sub_return - subtract the atomic variable
|
* atomic_sub_return - subtract the atomic variable
|
||||||
* @i: integer value to subtract
|
* @i: integer value to subtract
|
||||||
|
@ -102,6 +140,14 @@ static inline int atomic_sub_return(int i, atomic_t *v)
|
||||||
return __atomic_add_return(-i, v);
|
return __atomic_add_return(-i, v);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
static inline int atomic_fetch_sub(int i, atomic_t *v)
|
||||||
|
{
|
||||||
|
if (IS_21BIT_CONST(i))
|
||||||
|
return __atomic_fetch_sub(i, v);
|
||||||
|
|
||||||
|
return __atomic_fetch_add(-i, v);
|
||||||
|
}
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* __atomic_add_unless - add unless the number is a given value
|
* __atomic_add_unless - add unless the number is a given value
|
||||||
* @v: pointer of type atomic_t
|
* @v: pointer of type atomic_t
|
||||||
|
|
Loading…
Reference in a new issue