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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: Tejun Heo <tj@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Christoph Lameter 2010-12-06 11:39:59 -06:00 committed by Tejun Heo
parent a3383e8372
commit a663ffff1d
1 changed files with 71 additions and 0 deletions
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71
include/linux/percpu.h
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@ -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