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authorChristoph Lameter <cl@linux.com>2010-12-08 16:22:55 +0100
committerTejun Heo <tj@kernel.org>2010-12-17 15:07:19 +0100
commit909ea96468096b07fbb41aaf69be060d92bd9271 (patch)
treea7e015edd96b5f674874fe78cdd889769e130a2a /include/asm-generic
parent780f36d8b3fa9572f731d4fb85067b2e45e6f993 (diff)
core: Replace __get_cpu_var with __this_cpu_read if not used for an address.
__get_cpu_var() can be replaced with this_cpu_read and will then use a single read instruction with implied address calculation to access the correct per cpu instance. However, the address of a per cpu variable passed to __this_cpu_read() cannot be determined (since it's an implied address conversion through segment prefixes). Therefore apply this only to uses of __get_cpu_var where the address of the variable is not used. Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Hugh Dickins <hughd@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/irq_regs.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/include/asm-generic/irq_regs.h b/include/asm-generic/irq_regs.h
index 5ae1d07d4a1..6bf9355fa7e 100644
--- a/include/asm-generic/irq_regs.h
+++ b/include/asm-generic/irq_regs.h
@@ -22,15 +22,15 @@ DECLARE_PER_CPU(struct pt_regs *, __irq_regs);
static inline struct pt_regs *get_irq_regs(void)
{
- return __get_cpu_var(__irq_regs);
+ return __this_cpu_read(__irq_regs);
}
static inline struct pt_regs *set_irq_regs(struct pt_regs *new_regs)
{
- struct pt_regs *old_regs, **pp_regs = &__get_cpu_var(__irq_regs);
+ struct pt_regs *old_regs;
- old_regs = *pp_regs;
- *pp_regs = new_regs;
+ old_regs = __this_cpu_read(__irq_regs);
+ __this_cpu_write(__irq_regs, new_regs);
return old_regs;
}