[PATCH] on_each_cpu(): disable local interrupts

When on_each_cpu() runs the callback on other CPUs, it runs with local
interrupts disabled.  So we should run the function with local interrupts
disabled on this CPU, too.

And do the same for UP, so the callback is run in the same environment on both
UP and SMP.  (strictly it should do preempt_disable() too, but I think
local_irq_disable is sufficiently equivalent).

Also uninlines on_each_cpu().  softirq.c was the most appropriate file I could
find, but it doesn't seem to justify creating a new file.

Oh, and fix up that comment over (under?) x86's smp_call_function().  It
drives me nuts.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 14 deletions

diff --git a/include/linux/smp.h b/include/linux/smp.h
index 44153fdf73fc..d699a16b0cb2 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -52,23 +52,12 @@ extern void smp_cpus_done(unsigned int max_cpus);
 /*
  * Call a function on all other processors
  */
-extern int smp_call_function (void (*func) (void *info), void *info,
-                              int retry, int wait);
+int smp_call_function(void(*func)(void *info), void *info, int retry, int wait);
 
 /*
  * Call a function on all processors
  */
-static inline int on_each_cpu(void (*func) (void *info), void *info,
-                              int retry, int wait)
-{
-        int ret = 0;
-
-        preempt_disable();
-        ret = smp_call_function(func, info, retry, wait);
-        func(info);
-        preempt_enable();
-        return ret;
-}
+int on_each_cpu(void (*func) (void *info), void *info, int retry, int wait);
 
 #define MSG_ALL_BUT_SELF        0x8000  /* Assume <32768 CPU's */
 #define MSG_ALL                 0x8001
@@ -94,7 +83,13 @@ void smp_prepare_boot_cpu(void);
 #define raw_smp_processor_id()                  0
 #define hard_smp_processor_id()                 0
 #define smp_call_function(func,info,retry,wait) ({ 0; })
-#define on_each_cpu(func,info,retry,wait)       ({ func(info); 0; })
+#define on_each_cpu(func,info,retry,wait)       \
+        ({                                      \
+                local_irq_disable();            \
+                func(info);                     \
+                local_irq_enable();             \
+                0;                              \
+        })
 static inline void smp_send_reschedule(int cpu) { }
 #define num_booting_cpus()                      1
 #define smp_prepare_boot_cpu()                  do {} while (0)