preempt: Cleanup the macro maze a bit

/* preempt_count() and related functions, depends on PREEMPT_NEED_RESCHED */

#include <asm/preempt.h>

#define nmi_count()	(preempt_count() & NMI_MASK)

#define hardirq_count()	(preempt_count() & HARDIRQ_MASK)

#define softirq_count()	(preempt_count() & SOFTIRQ_MASK)

#define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \

				 | NMI_MASK))

#define irq_count()	(nmi_count() | hardirq_count() | softirq_count())

/*

 * Are we doing bottom half or hardware interrupt processing?

 * Macros to retrieve the current execution context:

 *

 * in_irq()       - We're in (hard) IRQ context

 * in_softirq()   - We have BH disabled, or are processing softirqs

 * in_interrupt() - We're in NMI,IRQ,SoftIRQ context or have BH disabled

 * in_serving_softirq() - We're in softirq context

 * in_nmi()		- We're in NMI context

 * in_hardirq()		- We're in hard IRQ context

 * in_serving_softirq()	- We're in softirq context

 * in_task()		- We're in task context

 *

 * Note: due to the BH disabled confusion: in_softirq(),in_interrupt() really

 *       should not be used in new code.

 */

#define in_nmi()		(nmi_count())

#define in_hardirq()		(hardirq_count())

#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)

#define in_task()		(!(in_nmi() | in_hardirq() | in_serving_softirq()))

/*

 * The following macros are deprecated and should not be used in new code:

 * in_irq()       - Obsolete version of in_hardirq()

 * in_softirq()   - We have BH disabled, or are processing softirqs

 * in_interrupt() - We're in NMI,IRQ,SoftIRQ context or have BH disabled

 */

#define in_irq()		(hardirq_count())

#define in_softirq()		(softirq_count())

#define in_interrupt()		(irq_count())

#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)

#define in_nmi()		(preempt_count() & NMI_MASK)

#define in_task()		(!(preempt_count() & \

				   (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)))

/*

 * The preempt_count offset after preempt_disable();