Call a function on a target CPU but do the right thing when
we're already on that CPU. That's the main difference from
smp_call_function_single
which does the wrong thing in this case (erroring out)
Another advantage is that it is also defined for the UP case, avoiding
some ifdefs.
I also dropped retry (which never did anything) and wait (because the on
current cpu case will always wait)
Signed-off-by: Andi Kleen <[EMAIL PROTECTED]>
---
include/linux/smp.h | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
Index: linux/include/linux/smp.h
===================================================================
--- linux.orig/include/linux/smp.h
+++ linux/include/linux/smp.h
@@ -138,4 +138,26 @@ static inline void smp_send_reschedule(i
void smp_setup_processor_id(void);
+#ifdef CONFIG_SMP
+/* Similar to smp_call_function_single, but DTRT when we're already
+ on the right CPU. */
+static inline void on_cpu_single(int cpu, void (*func)(void *), void *info)
+{
+ int me = get_cpu();
+ if (cpu == me) {
+ func(info);
+ put_cpu();
+ } else {
+ put_cpu();
+ /* wait is forced on because the me==cpu case above will always
wait */
+ smp_call_function_single(cpu, func, info, 0, 1);
+ }
+}
+#else
+static inline void on_cpu_single(int cpu, void (*func)(void *), void *info)
+{
+ func(info);
+}
+#endif
+
#endif /* __LINUX_SMP_H */
-
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