Re: [patch, -rc6] x86_64: UP build fixes

[Ingo Molnar <mingo@elte.hu>]

* Ingo Molnar <mingo@elte.hu> wrote:

> > on_each_cpu() does this and one caller (at least) relies upon it 
> > (invalidate_bh_lrus(), iirc).
> 
> ok, fair enough. Then this is a (minor) bugfix as well.

ok, this doesnt build on some configs - so the replacement patch below 
moves the UP variant to a function (which makes sense anyway).

	Ingo

--------------->
Subject: x86_64: build fixes
From: Ingo Molnar <mingo@elte.hu>

x86_64 does not build cleanly on UP:

arch/x86_64/kernel/vsyscall.c: In function 'cpu_vsyscall_notifier':
arch/x86_64/kernel/vsyscall.c:282: warning: implicit declaration of function 'smp_call_function_single'
arch/x86_64/kernel/vsyscall.c: At top level:
arch/x86_64/kernel/vsyscall.c:279: warning: 'cpu_vsyscall_notifier' defined but not used

this patch fixes it by making smp_call_function_single() globally available.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 include/asm-x86_64/smp.h |   11 ++---------
 include/linux/smp.h      |   10 +++++++---
 kernel/sched.c           |   19 +++++++++++++++++++
 3 files changed, 28 insertions(+), 12 deletions(-)

Index: linux/include/asm-x86_64/smp.h
===================================================================
--- linux.orig/include/asm-x86_64/smp.h
+++ linux/include/asm-x86_64/smp.h
@@ -115,16 +115,9 @@ static __inline int logical_smp_processo
 }
 
 #ifdef CONFIG_SMP
-#define cpu_physical_id(cpu)		x86_cpu_to_apicid[cpu]
+# define cpu_physical_id(cpu)		x86_cpu_to_apicid[cpu]
 #else
-#define cpu_physical_id(cpu)		boot_cpu_id
-static inline int smp_call_function_single(int cpuid, void (*func) (void *info),
-				void *info, int retry, int wait)
-{
-	/* Disable interrupts here? */
-	func(info);
-	return 0;
-}
+# define cpu_physical_id(cpu)		boot_cpu_id
 #endif /* !CONFIG_SMP */
 #endif
 
Index: linux/include/linux/smp.h
===================================================================
--- linux.orig/include/linux/smp.h
+++ linux/include/linux/smp.h
@@ -53,9 +53,6 @@ extern void smp_cpus_done(unsigned int m
  */
 int smp_call_function(void(*func)(void *info), void *info, int retry, int wait);
 
-int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,
-				int retry, int wait);
-
 /*
  * Call a function on all processors
  */
@@ -103,6 +100,13 @@ static inline void smp_send_reschedule(i
 #endif /* !SMP */
 
 /*
+ * Call a function on a specific CPU (on UP the function gets executed
+ * on the current CPU, immediately):
+ */
+int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,
+			     int retry, int wait);
+
+/*
  * smp_processor_id(): get the current CPU ID.
  *
  * if DEBUG_PREEMPT is enabled the we check whether it is
Index: linux/kernel/sched.c
===================================================================
--- linux.orig/kernel/sched.c
+++ linux/kernel/sched.c
@@ -1110,6 +1110,25 @@ repeat:
 	task_rq_unlock(rq, &flags);
 }
 
+#ifndef CONFIG_SMP
+/*
+ * Call a function on a specific CPU (on UP the function gets executed
+ * on the current CPU, immediately):
+ */
+int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,
+			     int retry, int wait)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	func(info);
+	local_irq_restore(flags);
+
+	return 0;
+}
+EXPORT_SYMBOL(smp_call_function_single);
+#endif
+
 /***
  * kick_process - kick a running thread to enter/exit the kernel
  * @p: the to-be-kicked thread