kernel-provide-a-__smp_call_function_single-stub-for-config_smp-fix

x86_64 allnoconfig:

  kernel/up.c:25: error: redefinition of '__smp_call_function_single'
  include/linux/smp.h:154: note: previous definition of '__smp_call_function_single' was here

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/smp.h

@@ -49,6 +49,9 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
 		smp_call_func_t func, void *info, bool wait,
 		gfp_t gfp_flags);
 
+void __smp_call_function_single(int cpuid, struct call_single_data *data,
+				int wait);
+
 #ifdef CONFIG_SMP
 
 #include <linux/preempt.h>
@@ -95,9 +98,6 @@ int smp_call_function(smp_call_func_t func, void *info, int wait);
 void smp_call_function_many(const struct cpumask *mask,
 			    smp_call_func_t func, void *info, bool wait);
 
-void __smp_call_function_single(int cpuid, struct call_single_data *data,
-				int wait);
-
 int smp_call_function_any(const struct cpumask *mask,
 			  smp_call_func_t func, void *info, int wait);
 
@@ -151,12 +151,6 @@ smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
 
 static inline void kick_all_cpus_sync(void) {  }
 
-static inline void __smp_call_function_single(int cpuid,
-		struct call_single_data *data, int wait)
-{
-	on_each_cpu(data->func, data->info, wait);
-}
-
 #endif /* !SMP */
 
 /*