Let smp_call_function_single return -EBUSY on UP

All architectures that have an implementation of smp_call_function_single
let it return -EBUSY if it is asked to execute func on the current cpu.
(akpm: except for x86_64).  Therefore the UP version must always return
-EBUSY.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 4 deletions

diff --git a/include/linux/smp.h b/include/linux/smp.h
index 3f70149eabbb..96ac21f8dd73 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -6,6 +6,7 @@
  *              Alan Cox. <alan@redhat.com>
  */
 
+#include <linux/errno.h>
 
 extern void cpu_idle(void);
 
@@ -99,11 +100,9 @@ static inline void smp_send_reschedule(int cpu) { }
 #define num_booting_cpus()                      1
 #define smp_prepare_boot_cpu()                  do {} while (0)
 static inline int smp_call_function_single(int cpuid, void (*func) (void *info),
-                                void *info, int retry, int wait)
+                                           void *info, int retry, int wait)
 {
-        /* Disable interrupts here? */
-        func(info);
-        return 0;
+        return -EBUSY;
 }
 
 #endif /* !SMP */