irq: Do not attempt to create subdirectories if /proc/irq/<irq> failed

If a parent directory (ie /proc/irq/<irq>) could not be created
we should not attempt to create subdirectories. Otherwise it
would lead that "smp_affinity" and "spurious" entries are may be
registered under /proc root instead of a proper place.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <20091026202811.GD5321@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/irq/proc.c

@@ -214,6 +214,8 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc)
 
 	/* create /proc/irq/1234 */
 	desc->dir = proc_mkdir(name, root_irq_dir);
+	if (!desc->dir)
+		return;
 
 #ifdef CONFIG_SMP
 	/* create /proc/irq/<irq>/smp_affinity */