s390/test_unwind: use timer instead of udelay

#include <linux/kallsyms.h>

#include <linux/kthread.h>

#include <linux/module.h>

#include <linux/timer.h>

#include <linux/slab.h>

#include <linux/string.h>

#include <linux/kprobes.h>

#include <linux/wait.h>

#include <asm/irq.h>

#include <asm/delay.h>

#define BT_BUF_SIZE (PAGE_SIZE * 4)

	return unwindme_func2((struct unwindme *)u);

}

static void unwindme_irq_handler(struct ext_code ext_code,

				       unsigned int param32,

				       unsigned long param64)

static void unwindme_timer_fn(struct timer_list *unused)

{

	struct unwindme *u = READ_ONCE(unwindme);

	if (u && u->task == current) {

	if (u) {

		unwindme = NULL;

		u->task = NULL;

		u->ret = unwindme_func1(u);

		complete(&u->task_ready);

	}

}

static struct timer_list unwind_timer;

static int test_unwind_irq(struct unwindme *u)

{

	preempt_disable();

	if (register_external_irq(EXT_IRQ_CLK_COMP, unwindme_irq_handler)) {

		pr_info("Couldn't register external interrupt handler");

		return -1;

	}

	u->task = current;

	unwindme = u;

	udelay(1);

	unregister_external_irq(EXT_IRQ_CLK_COMP, unwindme_irq_handler);

	preempt_enable();

	init_completion(&u->task_ready);

	timer_setup(&unwind_timer, unwindme_timer_fn, 0);

	mod_timer(&unwind_timer, jiffies + 1);

	wait_for_completion(&u->task_ready);

	return u->ret;

}