x86, ia64, smp: use workqueues unconditionally during do_boot_cpu()

Workqueues are now initialized as part of the early_initcall().  So they
are available for use during cold boot process aswell.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/ia64/kernel/smpboot.c

@@ -508,21 +508,18 @@ do_boot_cpu (int sapicid, int cpu)
 		.done	= COMPLETION_INITIALIZER(c_idle.done),
 	};
 
+	/*
+	 * We can't use kernel_thread since we must avoid to
+	 * reschedule the child.
+	 */
  	c_idle.idle = get_idle_for_cpu(cpu);
  	if (c_idle.idle) {
 		init_idle(c_idle.idle, cpu);
  		goto do_rest;
 	}
 
-	/*
-	 * We can't use kernel_thread since we must avoid to reschedule the child.
-	 */
-	if (!keventd_up())
-		c_idle.work.func(&c_idle.work);
-	else {
 	schedule_work(&c_idle.work);
 	wait_for_completion(&c_idle.done);
-	}
 
 	if (IS_ERR(c_idle.idle))
 		panic("failed fork for CPU %d", cpu);

arch/x86/kernel/smpboot.c

@@ -735,12 +735,8 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu)
 		goto do_rest;
 	}
 
-	if (!keventd_up())
-		c_idle.work.func(&c_idle.work);
-	else {
 	schedule_work(&c_idle.work);
 	wait_for_completion(&c_idle.done);
-	}
 
 	if (IS_ERR(c_idle.idle)) {
 		printk("failed fork for CPU %d\n", cpu);