Commit f7b64fe8 authored by Tejun Heo's avatar Tejun Heo
Browse files

percpu: make access macros universal 



Now that per_cpu__ prefix is gone, there's no distinction between
static and dynamic percpu variables.  Make get_cpu_var() take dynamic
percpu variables and ensure that all macros have parentheses around
the parameter evaluation and evaluate the variable parameter only once
such that any expression which evaluates to percpu address can be used
safely.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent dd17c8f7

include/linux/percpu.h

+14 −9
Original line number Diff line number Diff line
@@ -27,10 +27,13 @@ 
 * we force a syntax error here if it isn't.

 */

#define get_cpu_var(var) (*({				\

	extern int simple_identifier_##var(void);	\

	preempt_disable();				\

	&__get_cpu_var(var); }))

#define put_cpu_var(var) preempt_enable()



#define put_cpu_var(var) do {				\

	(void)(var);					\

	preempt_enable();				\

} while (0)



#ifdef CONFIG_SMP
@@ -182,17 +185,19 @@ static inline void *pcpu_lpage_remapped(void *kaddr) 
#ifndef percpu_read

# define percpu_read(var)						\

  ({									\

	typeof(var) __tmp_var__;					\

	__tmp_var__ = get_cpu_var(var);					\

	put_cpu_var(var);						\

	__tmp_var__;							\

	typeof(var) *pr_ptr__ = &(var);					\

	typeof(var) pr_ret__;						\

	pr_ret__ = get_cpu_var(*pr_ptr__);				\

	put_cpu_var(*pr_ptr__);						\

	pr_ret__;							\

  })

#endif



#define __percpu_generic_to_op(var, val, op)				\

do {									\

	get_cpu_var(var) op val;					\

	put_cpu_var(var);						\

	typeof(var) *pgto_ptr__ = &(var);				\

	get_cpu_var(*pgto_ptr__) op val;				\

	put_cpu_var(*pgto_ptr__);					\

} while (0)



#ifndef percpu_write
@@ -304,7 +309,7 @@ do { \ 
#define _this_cpu_generic_to_op(pcp, val, op)				\

do {									\

	preempt_disable();						\

	*__this_cpu_ptr(&pcp) op val;					\

	*__this_cpu_ptr(&(pcp)) op val;					\

	preempt_enable();						\

} while (0)

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