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Commit a663ffff authored by Christoph Lameter's avatar Christoph Lameter Committed by Tejun Heo
Browse files

percpu: Generic support for this_cpu_add, sub, dec, inc_return 



Introduce generic support for this_cpu_add_return etc.

The fallback is to realize these operations with simpler __this_cpu_ops.

tj: - Reformatted __cpu_size_call_return2() to make it more consistent
      with its neighbors.
    - Dropped unnecessary temp variable ret__ from
      __this_cpu_generic_add_return().

Reviewed-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent a3383e83

include/linux/percpu.h

+71 −0
Original line number Diff line number Diff line
@@ -240,6 +240,21 @@ extern void __bad_size_call_parameter(void); 
	pscr_ret__;							\

})



#define __pcpu_size_call_return2(stem, variable, ...)			\

({									\

	typeof(variable) 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__;							\

})



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

do {									\

	__verify_pcpu_ptr(&(variable));					\
@@ -529,6 +544,62 @@ do { \ 
# define __this_cpu_xor(pcp, val)	__pcpu_size_call(__this_cpu_xor_, (pcp), (val))

#endif



#define _this_cpu_generic_add_return(pcp, val)				\

({									\

	typeof(pcp) ret__;						\

	preempt_disable();						\

	__this_cpu_add(pcp, val);					\

	ret__ = __this_cpu_read(pcp);					\

	preempt_enable();						\

	ret__;								\

})



#ifndef this_cpu_add_return

# ifndef this_cpu_add_return_1

#  define this_cpu_add_return_1(pcp, val)	_this_cpu_generic_add_return(pcp, val)

# endif

# ifndef this_cpu_add_return_2

#  define this_cpu_add_return_2(pcp, val)	_this_cpu_generic_add_return(pcp, val)

# endif

# ifndef this_cpu_add_return_4

#  define this_cpu_add_return_4(pcp, val)	_this_cpu_generic_add_return(pcp, val)

# endif

# ifndef this_cpu_add_return_8

#  define this_cpu_add_return_8(pcp, val)	_this_cpu_generic_add_return(pcp, val)

# endif

# define this_cpu_add_return(pcp, val)	__pcpu_size_call_return2(this_cpu_add_return_, pcp, val)

#endif



#define this_cpu_sub_return(pcp, val)	this_cpu_add_return(pcp, -(val))

#define this_cpu_inc_return(pcp)	this_cpu_add_return(pcp, 1)

#define this_cpu_dec_return(pcp)	this_cpu_add_return(pcp, -1)



#define __this_cpu_generic_add_return(pcp, val)				\

({									\

	__this_cpu_add(pcp, val);					\

	__this_cpu_read(pcp);						\

})



#ifndef __this_cpu_add_return

# ifndef __this_cpu_add_return_1

#  define __this_cpu_add_return_1(pcp, val)	__this_cpu_generic_add_return(pcp, val)

# endif

# ifndef __this_cpu_add_return_2

#  define __this_cpu_add_return_2(pcp, val)	__this_cpu_generic_add_return(pcp, val)

# endif

# ifndef __this_cpu_add_return_4

#  define __this_cpu_add_return_4(pcp, val)	__this_cpu_generic_add_return(pcp, val)

# endif

# ifndef __this_cpu_add_return_8

#  define __this_cpu_add_return_8(pcp, val)	__this_cpu_generic_add_return(pcp, val)

# endif

# define __this_cpu_add_return(pcp, val)	__pcpu_size_call_return2(this_cpu_add_return_, pcp, val)

#endif



#define __this_cpu_sub_return(pcp, val)	this_cpu_add_return(pcp, -(val))

#define __this_cpu_inc_return(pcp)	this_cpu_add_return(pcp, 1)

#define __this_cpu_dec_return(pcp)	this_cpu_add_return(pcp, -1)



/*

 * IRQ safe versions of the per cpu RMW operations. Note that these operations

 * are *not* safe against modification of the same variable from another