Commit c5c0ba95 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

percpu: Add {raw,this}_cpu_try_cmpxchg() 



Add the try_cmpxchg() form to the per-cpu ops.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230531132323.587480729@infradead.org
parent 8c8b096a

include/asm-generic/percpu.h

+109 −4
Original line number Diff line number Diff line
@@ -89,16 +89,37 @@ do { \ 
	__ret;								\

})



#define raw_cpu_generic_cmpxchg(pcp, oval, nval)			\

#define __cpu_fallback_try_cmpxchg(pcp, ovalp, nval, _cmpxchg)		\

({									\

	typeof(pcp) __val, __old = *(ovalp);				\

	__val = _cmpxchg(pcp, __old, nval);				\

	if (__val != __old)						\

		*(ovalp) = __val;					\

	__val == __old;							\

})



#define raw_cpu_generic_try_cmpxchg(pcp, ovalp, nval)			\

({									\

	typeof(pcp) *__p = raw_cpu_ptr(&(pcp));				\

	typeof(pcp) __ret;						\

	__ret = *__p;							\

	if (__ret == (oval))						\

	typeof(pcp) __val = *__p, __old = *(ovalp);			\

	bool __ret;							\

	if (__val == __old) {						\

		*__p = nval;						\

		__ret = true;						\

	} else {							\

		*(ovalp) = __val;					\

		__ret = false;						\

	}								\

	__ret;								\

})



#define raw_cpu_generic_cmpxchg(pcp, oval, nval)			\

({									\

	typeof(pcp) __old = (oval);					\

	raw_cpu_generic_try_cmpxchg(pcp, &__old, nval);			\

	__old;								\

})



#define raw_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \

({									\

	typeof(pcp1) *__p1 = raw_cpu_ptr(&(pcp1));			\
@@ -170,6 +191,16 @@ do { \ 
	__ret;								\

})



#define this_cpu_generic_try_cmpxchg(pcp, ovalp, nval)			\

({									\

	bool __ret;							\

	unsigned long __flags;						\

	raw_local_irq_save(__flags);					\

	__ret = raw_cpu_generic_try_cmpxchg(pcp, ovalp, nval);		\

	raw_local_irq_restore(__flags);					\

	__ret;								\

})



#define this_cpu_generic_cmpxchg(pcp, oval, nval)			\

({									\

	typeof(pcp) __ret;						\
@@ -282,6 +313,43 @@ do { \ 
#define raw_cpu_xchg_8(pcp, nval)	raw_cpu_generic_xchg(pcp, nval)

#endif



#ifndef raw_cpu_try_cmpxchg_1

#ifdef raw_cpu_cmpxchg_1

#define raw_cpu_try_cmpxchg_1(pcp, ovalp, nval) \

	__cpu_fallback_try_cmpxchg(pcp, ovalp, nval, raw_cpu_cmpxchg_1)

#else

#define raw_cpu_try_cmpxchg_1(pcp, ovalp, nval) \

	raw_cpu_generic_try_cmpxchg(pcp, ovalp, nval)

#endif

#endif

#ifndef raw_cpu_try_cmpxchg_2

#ifdef raw_cpu_cmpxchg_2

#define raw_cpu_try_cmpxchg_2(pcp, ovalp, nval) \

	__cpu_fallback_try_cmpxchg(pcp, ovalp, nval, raw_cpu_cmpxchg_2)

#else

#define raw_cpu_try_cmpxchg_2(pcp, ovalp, nval) \

	raw_cpu_generic_try_cmpxchg(pcp, ovalp, nval)

#endif

#endif

#ifndef raw_cpu_try_cmpxchg_4

#ifdef raw_cpu_cmpxchg_4

#define raw_cpu_try_cmpxchg_4(pcp, ovalp, nval) \

	__cpu_fallback_try_cmpxchg(pcp, ovalp, nval, raw_cpu_cmpxchg_4)

#else

#define raw_cpu_try_cmpxchg_4(pcp, ovalp, nval) \

	raw_cpu_generic_try_cmpxchg(pcp, ovalp, nval)

#endif

#endif

#ifndef raw_cpu_try_cmpxchg_8

#ifdef raw_cpu_cmpxchg_8

#define raw_cpu_try_cmpxchg_8(pcp, ovalp, nval) \

	__cpu_fallback_try_cmpxchg(pcp, ovalp, nval, raw_cpu_cmpxchg_8)

#else

#define raw_cpu_try_cmpxchg_8(pcp, ovalp, nval) \

	raw_cpu_generic_try_cmpxchg(pcp, ovalp, nval)

#endif

#endif



#ifndef raw_cpu_cmpxchg_1

#define raw_cpu_cmpxchg_1(pcp, oval, nval) \

	raw_cpu_generic_cmpxchg(pcp, oval, nval)
@@ -407,6 +475,43 @@ do { \ 
#define this_cpu_xchg_8(pcp, nval)	this_cpu_generic_xchg(pcp, nval)

#endif



#ifndef this_cpu_try_cmpxchg_1

#ifdef this_cpu_cmpxchg_1

#define this_cpu_try_cmpxchg_1(pcp, ovalp, nval) \

	__cpu_fallback_try_cmpxchg(pcp, ovalp, nval, this_cpu_cmpxchg_1)

#else

#define this_cpu_try_cmpxchg_1(pcp, ovalp, nval) \

	this_cpu_generic_try_cmpxchg(pcp, ovalp, nval)

#endif

#endif

#ifndef this_cpu_try_cmpxchg_2

#ifdef this_cpu_cmpxchg_2

#define this_cpu_try_cmpxchg_2(pcp, ovalp, nval) \

	__cpu_fallback_try_cmpxchg(pcp, ovalp, nval, this_cpu_cmpxchg_2)

#else

#define this_cpu_try_cmpxchg_2(pcp, ovalp, nval) \

	this_cpu_generic_try_cmpxchg(pcp, ovalp, nval)

#endif

#endif

#ifndef this_cpu_try_cmpxchg_4

#ifdef this_cpu_cmpxchg_4

#define this_cpu_try_cmpxchg_4(pcp, ovalp, nval) \

	__cpu_fallback_try_cmpxchg(pcp, ovalp, nval, this_cpu_cmpxchg_4)

#else

#define this_cpu_try_cmpxchg_4(pcp, ovalp, nval) \

	this_cpu_generic_try_cmpxchg(pcp, ovalp, nval)

#endif

#endif

#ifndef this_cpu_try_cmpxchg_8

#ifdef this_cpu_cmpxchg_8

#define this_cpu_try_cmpxchg_8(pcp, ovalp, nval) \

	__cpu_fallback_try_cmpxchg(pcp, ovalp, nval, this_cpu_cmpxchg_8)

#else

#define this_cpu_try_cmpxchg_8(pcp, ovalp, nval) \

	this_cpu_generic_try_cmpxchg(pcp, ovalp, nval)

#endif

#endif



#ifndef this_cpu_cmpxchg_1

#define this_cpu_cmpxchg_1(pcp, oval, nval) \

	this_cpu_generic_cmpxchg(pcp, oval, nval)

include/linux/percpu-defs.h

+19 −0
Original line number Diff line number Diff line
@@ -343,6 +343,21 @@ static __always_inline void __this_cpu_preempt_check(const char *op) { } 
	pscr2_ret__;							\

})



#define __pcpu_size_call_return2bool(stem, variable, ...)		\

({									\

	bool pscr2_ret__;						\

	__verify_pcpu_ptr(&(variable));					\

	switch(sizeof(variable)) {					\

	case 1: pscr2_ret__ = stem##1(variable, __VA_ARGS__); break;	\

	case 2: pscr2_ret__ = stem##2(variable, __VA_ARGS__); break;	\

	case 4: pscr2_ret__ = stem##4(variable, __VA_ARGS__); break;	\

	case 8: pscr2_ret__ = stem##8(variable, __VA_ARGS__); break;	\

	default:							\

		__bad_size_call_parameter(); break;			\

	}								\

	pscr2_ret__;							\

})



/*

 * Special handling for cmpxchg_double.  cmpxchg_double is passed two

 * percpu variables.  The first has to be aligned to a double word
@@ -426,6 +441,8 @@ do { \ 
#define raw_cpu_xchg(pcp, nval)		__pcpu_size_call_return2(raw_cpu_xchg_, pcp, nval)

#define raw_cpu_cmpxchg(pcp, oval, nval) \

	__pcpu_size_call_return2(raw_cpu_cmpxchg_, pcp, oval, nval)

#define raw_cpu_try_cmpxchg(pcp, ovalp, nval) \

	__pcpu_size_call_return2bool(raw_cpu_try_cmpxchg_, pcp, ovalp, nval)

#define raw_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \

	__pcpu_double_call_return_bool(raw_cpu_cmpxchg_double_, pcp1, pcp2, oval1, oval2, nval1, nval2)
@@ -513,6 +530,8 @@ do { \ 
#define this_cpu_xchg(pcp, nval)	__pcpu_size_call_return2(this_cpu_xchg_, pcp, nval)

#define this_cpu_cmpxchg(pcp, oval, nval) \

	__pcpu_size_call_return2(this_cpu_cmpxchg_, pcp, oval, nval)

#define this_cpu_try_cmpxchg(pcp, ovalp, nval) \

	__pcpu_size_call_return2bool(this_cpu_try_cmpxchg_, pcp, ovalp, nval)

#define this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \

	__pcpu_double_call_return_bool(this_cpu_cmpxchg_double_, pcp1, pcp2, oval1, oval2, nval1, nval2)