From ded00a56e99555c3f4000ef3eebfd5fe0d574565 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Date: Sun, 17 Aug 2008 12:50:36 -0700 Subject: [PATCH] rcu: remove redundant ACCESS_ONCE definition from rcupreempt.c Remove the redundant definition of ACCESS_ONCE() from rcupreempt.c in favor of the one in compiler.h. Also merge the comment header from rcupreempt.c's definition into that in compiler.h. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- include/linux/compiler.h | 4 +++- kernel/rcupreempt.c | 8 -------- 2 files changed, 3 insertions(+), 9 deletions(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index c8bd2daf95e..8322141ee48 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -190,7 +190,9 @@ extern void __chk_io_ptr(const volatile void __iomem *); * ACCESS_ONCE() in different C statements. * * This macro does absolutely -nothing- to prevent the CPU from reordering, - * merging, or refetching absolutely anything at any time. + * merging, or refetching absolutely anything at any time. Its main intended + * use is to mediate communication between process-level code and irq/NMI + * handlers, all running on the same CPU. */ #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x)) diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c index 27827931ca0..ca4bbbe04aa 100644 --- a/kernel/rcupreempt.c +++ b/kernel/rcupreempt.c @@ -58,14 +58,6 @@ #include <linux/cpumask.h> #include <linux/rcupreempt_trace.h> -/* - * Macro that prevents the compiler from reordering accesses, but does - * absolutely -nothing- to prevent CPUs from reordering. This is used - * only to mediate communication between mainline code and hardware - * interrupt and NMI handlers. - */ -#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x)) - /* * PREEMPT_RCU data structures. */ -- GitLab