kernel: provide a __smp_call_function_single stub for !CONFIG_SMP

Signed-off-by: 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>

kernel/up.c

@@ -22,6 +22,17 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
 }
 EXPORT_SYMBOL(smp_call_function_single);
 
+void __smp_call_function_single(int cpu, struct call_single_data *csd,
+				int wait)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	csd->func(csd->info);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(__smp_call_function_single);
+
 int on_each_cpu(smp_call_func_t func, void *info, int wait)
 {
 	unsigned long flags;