include/asm-x86/atomic_64.h - kernel/msm-4.9 - Gitiles

 #ifndef __ARCH_X86_64_ATOMIC__
 #define __ARCH_X86_64_ATOMIC__

 #include <asm/alternative.h>
 #include <asm/cmpxchg.h>

 /* atomic_t should be 32 bit signed type */

 /*
  * Atomic operations that C can't guarantee us.  Useful for
  * resource counting etc..
  */

 #ifdef CONFIG_SMP
 #define LOCK "lock ; "
 #else
 #define LOCK ""
 #endif

 /*
  * Make sure gcc doesn't try to be clever and move things around
  * on us. We need to use _exactly_ the address the user gave us,
  * not some alias that contains the same information.
  */
 typedef struct {
 	int counter;
 } atomic_t;

 #define ATOMIC_INIT(i)	{ (i) }

 /**
  * atomic_read - read atomic variable
  * @v: pointer of type atomic_t
  *
  * Atomically reads the value of @v.
  */
 #define atomic_read(v)		((v)->counter)

 /**
  * atomic_set - set atomic variable
  * @v: pointer of type atomic_t
  * @i: required value
  *
  * Atomically sets the value of @v to @i.
  */
 #define atomic_set(v, i)		(((v)->counter) = (i))

 /**
  * atomic_add - add integer to atomic variable
  * @i: integer value to add
  * @v: pointer of type atomic_t
  *
  * Atomically adds @i to @v.
  */
 static inline void atomic_add(int i, atomic_t *v)
 {
 	asm volatile(LOCK_PREFIX "addl %1,%0"
 		     : "=m" (v->counter)
 		     : "ir" (i), "m" (v->counter));
 }

 /**
  * atomic_sub - subtract the atomic variable
  * @i: integer value to subtract
  * @v: pointer of type atomic_t
  *
  * Atomically subtracts @i from @v.
  */
 static inline void atomic_sub(int i, atomic_t *v)
 {
 	asm volatile(LOCK_PREFIX "subl %1,%0"
 		     : "=m" (v->counter)
 		     : "ir" (i), "m" (v->counter));
 }

 /**
  * atomic_sub_and_test - subtract value from variable and test result
  * @i: integer value to subtract
  * @v: pointer of type atomic_t
  *
  * Atomically subtracts @i from @v and returns
  * true if the result is zero, or false for all
  * other cases.
  */
 static inline int atomic_sub_and_test(int i, atomic_t *v)
 {
 	unsigned char c;

 	asm volatile(LOCK_PREFIX "subl %2,%0; sete %1"
 		     : "=m" (v->counter), "=qm" (c)
 		     : "ir" (i), "m" (v->counter) : "memory");
 	return c;
 }

 /**
  * atomic_inc - increment atomic variable
  * @v: pointer of type atomic_t
  *
  * Atomically increments @v by 1.
  */
 static inline void atomic_inc(atomic_t *v)
 {
 	asm volatile(LOCK_PREFIX "incl %0"
 		     : "=m" (v->counter)
 		     : "m" (v->counter));
 }

 /**
  * atomic_dec - decrement atomic variable
  * @v: pointer of type atomic_t
  *
  * Atomically decrements @v by 1.
  */
 static inline void atomic_dec(atomic_t *v)
 {
 	asm volatile(LOCK_PREFIX "decl %0"
 		     : "=m" (v->counter)
 		     : "m" (v->counter));
 }

 /**
  * atomic_dec_and_test - decrement and test
  * @v: pointer of type atomic_t
  *
  * Atomically decrements @v by 1 and
  * returns true if the result is 0, or false for all other
  * cases.
  */
 static inline int atomic_dec_and_test(atomic_t *v)
 {
 	unsigned char c;

 	asm volatile(LOCK_PREFIX "decl %0; sete %1"
 		     : "=m" (v->counter), "=qm" (c)
 		     : "m" (v->counter) : "memory");
 	return c != 0;
 }

 /**
  * atomic_inc_and_test - increment and test
  * @v: pointer of type atomic_t
  *
  * Atomically increments @v by 1
  * and returns true if the result is zero, or false for all
  * other cases.
  */
 static inline int atomic_inc_and_test(atomic_t *v)
 {
 	unsigned char c;

 	asm volatile(LOCK_PREFIX "incl %0; sete %1"
 		     : "=m" (v->counter), "=qm" (c)
 		     : "m" (v->counter) : "memory");
 	return c != 0;
 }

 /**
  * atomic_add_negative - add and test if negative
  * @i: integer value to add
  * @v: pointer of type atomic_t
  *
  * Atomically adds @i to @v and returns true
  * if the result is negative, or false when
  * result is greater than or equal to zero.
  */
 static inline int atomic_add_negative(int i, atomic_t *v)
 {
 	unsigned char c;

 	asm volatile(LOCK_PREFIX "addl %2,%0; sets %1"
 		     : "=m" (v->counter), "=qm" (c)
 		     : "ir" (i), "m" (v->counter) : "memory");
 	return c;
 }

 /**
  * atomic_add_return - add and return
  * @i: integer value to add
  * @v: pointer of type atomic_t
  *
  * Atomically adds @i to @v and returns @i + @v
  */
 static inline int atomic_add_return(int i, atomic_t *v)
 {
 	int __i = i;
 	asm volatile(LOCK_PREFIX "xaddl %0, %1"
 		     : "+r" (i), "+m" (v->counter)
 		     : : "memory");
 	return i + __i;
 }

 static inline int atomic_sub_return(int i, atomic_t *v)
 {
 	return atomic_add_return(-i, v);
 }

 #define atomic_inc_return(v)  (atomic_add_return(1, v))
 #define atomic_dec_return(v)  (atomic_sub_return(1, v))

 /* An 64bit atomic type */

 typedef struct {
 	long counter;
 } atomic64_t;

 #define ATOMIC64_INIT(i)	{ (i) }

 /**
  * atomic64_read - read atomic64 variable
  * @v: pointer of type atomic64_t
  *
  * Atomically reads the value of @v.
  * Doesn't imply a read memory barrier.
  */
 #define atomic64_read(v)		((v)->counter)

 /**
  * atomic64_set - set atomic64 variable
  * @v: pointer to type atomic64_t
  * @i: required value
  *
  * Atomically sets the value of @v to @i.
  */
 #define atomic64_set(v, i)		(((v)->counter) = (i))

 /**
  * atomic64_add - add integer to atomic64 variable
  * @i: integer value to add
  * @v: pointer to type atomic64_t
  *
  * Atomically adds @i to @v.
  */
 static inline void atomic64_add(long i, atomic64_t *v)
 {
 	asm volatile(LOCK_PREFIX "addq %1,%0"
 		     : "=m" (v->counter)
 		     : "ir" (i), "m" (v->counter));
 }

 /**
  * atomic64_sub - subtract the atomic64 variable
  * @i: integer value to subtract
  * @v: pointer to type atomic64_t
  *
  * Atomically subtracts @i from @v.
  */
 static inline void atomic64_sub(long i, atomic64_t *v)
 {
 	asm volatile(LOCK_PREFIX "subq %1,%0"
 		     : "=m" (v->counter)
 		     : "ir" (i), "m" (v->counter));
 }

 /**
  * atomic64_sub_and_test - subtract value from variable and test result
  * @i: integer value to subtract
  * @v: pointer to type atomic64_t
  *
  * Atomically subtracts @i from @v and returns
  * true if the result is zero, or false for all
  * other cases.
  */
 static inline int atomic64_sub_and_test(long i, atomic64_t *v)
 {
 	unsigned char c;

 	asm volatile(LOCK_PREFIX "subq %2,%0; sete %1"
 		     : "=m" (v->counter), "=qm" (c)
 		     : "ir" (i), "m" (v->counter) : "memory");
 	return c;
 }

 /**
  * atomic64_inc - increment atomic64 variable
  * @v: pointer to type atomic64_t
  *
  * Atomically increments @v by 1.
  */
 static inline void atomic64_inc(atomic64_t *v)
 {
 	asm volatile(LOCK_PREFIX "incq %0"
 		     : "=m" (v->counter)
 		     : "m" (v->counter));
 }

 /**
  * atomic64_dec - decrement atomic64 variable
  * @v: pointer to type atomic64_t
  *
  * Atomically decrements @v by 1.
  */
 static inline void atomic64_dec(atomic64_t *v)
 {
 	asm volatile(LOCK_PREFIX "decq %0"
 		     : "=m" (v->counter)
 		     : "m" (v->counter));
 }

 /**
  * atomic64_dec_and_test - decrement and test
  * @v: pointer to type atomic64_t
  *
  * Atomically decrements @v by 1 and
  * returns true if the result is 0, or false for all other
  * cases.
  */
 static inline int atomic64_dec_and_test(atomic64_t *v)
 {
 	unsigned char c;

 	asm volatile(LOCK_PREFIX "decq %0; sete %1"
 		     : "=m" (v->counter), "=qm" (c)
 		     : "m" (v->counter) : "memory");
 	return c != 0;
 }

 /**
  * atomic64_inc_and_test - increment and test
  * @v: pointer to type atomic64_t
  *
  * Atomically increments @v by 1
  * and returns true if the result is zero, or false for all
  * other cases.
  */
 static inline int atomic64_inc_and_test(atomic64_t *v)
 {
 	unsigned char c;

 	asm volatile(LOCK_PREFIX "incq %0; sete %1"
 		     : "=m" (v->counter), "=qm" (c)
 		     : "m" (v->counter) : "memory");
 	return c != 0;
 }

 /**
  * atomic64_add_negative - add and test if negative
  * @i: integer value to add
  * @v: pointer to type atomic64_t
  *
  * Atomically adds @i to @v and returns true
  * if the result is negative, or false when
  * result is greater than or equal to zero.
  */
 static inline int atomic64_add_negative(long i, atomic64_t *v)
 {
 	unsigned char c;

 	asm volatile(LOCK_PREFIX "addq %2,%0; sets %1"
 		     : "=m" (v->counter), "=qm" (c)
 		     : "ir" (i), "m" (v->counter) : "memory");
 	return c;
 }

 /**
  * atomic64_add_return - add and return
  * @i: integer value to add
  * @v: pointer to type atomic64_t
  *
  * Atomically adds @i to @v and returns @i + @v
  */
 static inline long atomic64_add_return(long i, atomic64_t *v)
 {
 	long __i = i;
 	asm volatile(LOCK_PREFIX "xaddq %0, %1;"
 		     : "+r" (i), "+m" (v->counter)
 		     : : "memory");
 	return i + __i;
 }

 static inline long atomic64_sub_return(long i, atomic64_t *v)
 {
 	return atomic64_add_return(-i, v);
 }

 #define atomic64_inc_return(v)  (atomic64_add_return(1, (v)))
 #define atomic64_dec_return(v)  (atomic64_sub_return(1, (v)))

 #define atomic64_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
 #define atomic64_xchg(v, new) (xchg(&((v)->counter), new))

 #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
 #define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))

 /**
  * atomic_add_unless - add unless the number is a given value
  * @v: pointer of type atomic_t
  * @a: the amount to add to v...
  * @u: ...unless v is equal to u.
  *
  * Atomically adds @a to @v, so long as it was not @u.
  * Returns non-zero if @v was not @u, and zero otherwise.
  */
 static inline int atomic_add_unless(atomic_t *v, int a, int u)
 {
 	int c, old;
 	c = atomic_read(v);
 	for (;;) {
 		if (unlikely(c == (u)))
 			break;
 		old = atomic_cmpxchg((v), c, c + (a));
 		if (likely(old == c))
 			break;
 		c = old;
 	}
 	return c != (u);
 }

 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

 /**
  * atomic64_add_unless - add unless the number is a given value
  * @v: pointer of type atomic64_t
  * @a: the amount to add to v...
  * @u: ...unless v is equal to u.
  *
  * Atomically adds @a to @v, so long as it was not @u.
  * Returns non-zero if @v was not @u, and zero otherwise.
  */
 static inline int atomic64_add_unless(atomic64_t *v, long a, long u)
 {
 	long c, old;
 	c = atomic64_read(v);
 	for (;;) {
 		if (unlikely(c == (u)))
 			break;
 		old = atomic64_cmpxchg((v), c, c + (a));
 		if (likely(old == c))
 			break;
 		c = old;
 	}
 	return c != (u);
 }

 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)

 /* These are x86-specific, used by some header files */
 #define atomic_clear_mask(mask, addr)					\
 	asm volatile(LOCK_PREFIX "andl %0,%1"				\
 		     : : "r" (~(mask)), "m" (*(addr)) : "memory")

 #define atomic_set_mask(mask, addr)					\
 	asm volatile(LOCK_PREFIX "orl %0,%1"				\
 		     : : "r" ((unsigned)(mask)), "m" (*(addr))		\
 		     : "memory")

 /* Atomic operations are already serializing on x86 */
 #define smp_mb__before_atomic_dec()	barrier()
 #define smp_mb__after_atomic_dec()	barrier()
 #define smp_mb__before_atomic_inc()	barrier()
 #define smp_mb__after_atomic_inc()	barrier()

 #include <asm-generic/atomic.h>
 #endif
	#ifndef __ARCH_X86_64_ATOMIC__
	#define __ARCH_X86_64_ATOMIC__

	#include <asm/alternative.h>
	#include <asm/cmpxchg.h>

	/* atomic_t should be 32 bit signed type */

	/*
	* Atomic operations that C can't guarantee us. Useful for
	* resource counting etc..
	*/

	#ifdef CONFIG_SMP
	#define LOCK "lock ; "
	#else
	#define LOCK ""
	#endif

	/*
	* Make sure gcc doesn't try to be clever and move things around
	* on us. We need to use _exactly_ the address the user gave us,
	* not some alias that contains the same information.
	*/
	typedef struct {
	int counter;
	} atomic_t;

	#define ATOMIC_INIT(i) { (i) }

	/**
	* atomic_read - read atomic variable
	* @v: pointer of type atomic_t
	*
	* Atomically reads the value of @v.
	*/
	#define atomic_read(v) ((v)->counter)

	/**
	* atomic_set - set atomic variable
	* @v: pointer of type atomic_t
	* @i: required value
	*
	* Atomically sets the value of @v to @i.
	*/
	#define atomic_set(v, i) (((v)->counter) = (i))

	/**
	* atomic_add - add integer to atomic variable
	* @i: integer value to add
	* @v: pointer of type atomic_t
	*
	* Atomically adds @i to @v.
	*/
	static inline void atomic_add(int i, atomic_t *v)
	{
	asm volatile(LOCK_PREFIX "addl %1,%0"
	: "=m" (v->counter)
	: "ir" (i), "m" (v->counter));
	}

	/**
	* atomic_sub - subtract the atomic variable
	* @i: integer value to subtract
	* @v: pointer of type atomic_t
	*
	* Atomically subtracts @i from @v.
	*/
	static inline void atomic_sub(int i, atomic_t *v)
	{
	asm volatile(LOCK_PREFIX "subl %1,%0"
	: "=m" (v->counter)
	: "ir" (i), "m" (v->counter));
	}

	/**
	* atomic_sub_and_test - subtract value from variable and test result
	* @i: integer value to subtract
	* @v: pointer of type atomic_t
	*
	* Atomically subtracts @i from @v and returns
	* true if the result is zero, or false for all
	* other cases.
	*/
	static inline int atomic_sub_and_test(int i, atomic_t *v)
	{
	unsigned char c;

	asm volatile(LOCK_PREFIX "subl %2,%0; sete %1"
	: "=m" (v->counter), "=qm" (c)
	: "ir" (i), "m" (v->counter) : "memory");
	return c;
	}

	/**
	* atomic_inc - increment atomic variable
	* @v: pointer of type atomic_t
	*
	* Atomically increments @v by 1.
	*/
	static inline void atomic_inc(atomic_t *v)
	{
	asm volatile(LOCK_PREFIX "incl %0"
	: "=m" (v->counter)
	: "m" (v->counter));
	}

	/**
	* atomic_dec - decrement atomic variable
	* @v: pointer of type atomic_t
	*
	* Atomically decrements @v by 1.
	*/
	static inline void atomic_dec(atomic_t *v)
	{
	asm volatile(LOCK_PREFIX "decl %0"
	: "=m" (v->counter)
	: "m" (v->counter));
	}

	/**
	* atomic_dec_and_test - decrement and test
	* @v: pointer of type atomic_t
	*
	* Atomically decrements @v by 1 and
	* returns true if the result is 0, or false for all other
	* cases.
	*/
	static inline int atomic_dec_and_test(atomic_t *v)
	{
	unsigned char c;

	asm volatile(LOCK_PREFIX "decl %0; sete %1"
	: "=m" (v->counter), "=qm" (c)
	: "m" (v->counter) : "memory");
	return c != 0;
	}

	/**
	* atomic_inc_and_test - increment and test
	* @v: pointer of type atomic_t
	*
	* Atomically increments @v by 1
	* and returns true if the result is zero, or false for all
	* other cases.
	*/
	static inline int atomic_inc_and_test(atomic_t *v)
	{
	unsigned char c;

	asm volatile(LOCK_PREFIX "incl %0; sete %1"
	: "=m" (v->counter), "=qm" (c)
	: "m" (v->counter) : "memory");
	return c != 0;
	}

	/**
	* atomic_add_negative - add and test if negative
	* @i: integer value to add
	* @v: pointer of type atomic_t
	*
	* Atomically adds @i to @v and returns true
	* if the result is negative, or false when
	* result is greater than or equal to zero.
	*/
	static inline int atomic_add_negative(int i, atomic_t *v)
	{
	unsigned char c;

	asm volatile(LOCK_PREFIX "addl %2,%0; sets %1"
	: "=m" (v->counter), "=qm" (c)
	: "ir" (i), "m" (v->counter) : "memory");
	return c;
	}

	/**
	* atomic_add_return - add and return
	* @i: integer value to add
	* @v: pointer of type atomic_t
	*
	* Atomically adds @i to @v and returns @i + @v
	*/
	static inline int atomic_add_return(int i, atomic_t *v)
	{
	int __i = i;
	asm volatile(LOCK_PREFIX "xaddl %0, %1"
	: "+r" (i), "+m" (v->counter)
	: : "memory");
	return i + __i;
	}

	static inline int atomic_sub_return(int i, atomic_t *v)
	{
	return atomic_add_return(-i, v);
	}

	#define atomic_inc_return(v) (atomic_add_return(1, v))
	#define atomic_dec_return(v) (atomic_sub_return(1, v))

	/* An 64bit atomic type */

	typedef struct {
	long counter;
	} atomic64_t;

	#define ATOMIC64_INIT(i) { (i) }

	/**
	* atomic64_read - read atomic64 variable
	* @v: pointer of type atomic64_t
	*
	* Atomically reads the value of @v.
	* Doesn't imply a read memory barrier.
	*/
	#define atomic64_read(v) ((v)->counter)

	/**
	* atomic64_set - set atomic64 variable
	* @v: pointer to type atomic64_t
	* @i: required value
	*
	* Atomically sets the value of @v to @i.
	*/
	#define atomic64_set(v, i) (((v)->counter) = (i))

	/**
	* atomic64_add - add integer to atomic64 variable
	* @i: integer value to add
	* @v: pointer to type atomic64_t
	*
	* Atomically adds @i to @v.
	*/
	static inline void atomic64_add(long i, atomic64_t *v)
	{
	asm volatile(LOCK_PREFIX "addq %1,%0"
	: "=m" (v->counter)
	: "ir" (i), "m" (v->counter));
	}

	/**
	* atomic64_sub - subtract the atomic64 variable
	* @i: integer value to subtract
	* @v: pointer to type atomic64_t
	*
	* Atomically subtracts @i from @v.
	*/
	static inline void atomic64_sub(long i, atomic64_t *v)
	{
	asm volatile(LOCK_PREFIX "subq %1,%0"
	: "=m" (v->counter)
	: "ir" (i), "m" (v->counter));
	}

	/**
	* atomic64_sub_and_test - subtract value from variable and test result
	* @i: integer value to subtract
	* @v: pointer to type atomic64_t
	*
	* Atomically subtracts @i from @v and returns
	* true if the result is zero, or false for all
	* other cases.
	*/
	static inline int atomic64_sub_and_test(long i, atomic64_t *v)
	{
	unsigned char c;

	asm volatile(LOCK_PREFIX "subq %2,%0; sete %1"
	: "=m" (v->counter), "=qm" (c)
	: "ir" (i), "m" (v->counter) : "memory");
	return c;
	}

	/**
	* atomic64_inc - increment atomic64 variable
	* @v: pointer to type atomic64_t
	*
	* Atomically increments @v by 1.
	*/
	static inline void atomic64_inc(atomic64_t *v)
	{
	asm volatile(LOCK_PREFIX "incq %0"
	: "=m" (v->counter)
	: "m" (v->counter));
	}

	/**
	* atomic64_dec - decrement atomic64 variable
	* @v: pointer to type atomic64_t
	*
	* Atomically decrements @v by 1.
	*/
	static inline void atomic64_dec(atomic64_t *v)
	{
	asm volatile(LOCK_PREFIX "decq %0"
	: "=m" (v->counter)
	: "m" (v->counter));
	}

	/**
	* atomic64_dec_and_test - decrement and test
	* @v: pointer to type atomic64_t
	*
	* Atomically decrements @v by 1 and
	* returns true if the result is 0, or false for all other
	* cases.
	*/
	static inline int atomic64_dec_and_test(atomic64_t *v)
	{
	unsigned char c;

	asm volatile(LOCK_PREFIX "decq %0; sete %1"
	: "=m" (v->counter), "=qm" (c)
	: "m" (v->counter) : "memory");
	return c != 0;
	}

	/**
	* atomic64_inc_and_test - increment and test
	* @v: pointer to type atomic64_t
	*
	* Atomically increments @v by 1
	* and returns true if the result is zero, or false for all
	* other cases.
	*/
	static inline int atomic64_inc_and_test(atomic64_t *v)
	{
	unsigned char c;

	asm volatile(LOCK_PREFIX "incq %0; sete %1"
	: "=m" (v->counter), "=qm" (c)
	: "m" (v->counter) : "memory");
	return c != 0;
	}

	/**
	* atomic64_add_negative - add and test if negative
	* @i: integer value to add
	* @v: pointer to type atomic64_t
	*
	* Atomically adds @i to @v and returns true
	* if the result is negative, or false when
	* result is greater than or equal to zero.
	*/
	static inline int atomic64_add_negative(long i, atomic64_t *v)
	{
	unsigned char c;

	asm volatile(LOCK_PREFIX "addq %2,%0; sets %1"
	: "=m" (v->counter), "=qm" (c)
	: "ir" (i), "m" (v->counter) : "memory");
	return c;
	}

	/**
	* atomic64_add_return - add and return
	* @i: integer value to add
	* @v: pointer to type atomic64_t
	*
	* Atomically adds @i to @v and returns @i + @v
	*/
	static inline long atomic64_add_return(long i, atomic64_t *v)
	{
	long __i = i;
	asm volatile(LOCK_PREFIX "xaddq %0, %1;"
	: "+r" (i), "+m" (v->counter)
	: : "memory");
	return i + __i;
	}

	static inline long atomic64_sub_return(long i, atomic64_t *v)
	{
	return atomic64_add_return(-i, v);
	}

	#define atomic64_inc_return(v) (atomic64_add_return(1, (v)))
	#define atomic64_dec_return(v) (atomic64_sub_return(1, (v)))

	#define atomic64_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
	#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))

	#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
	#define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))

	/**
	* atomic_add_unless - add unless the number is a given value
	* @v: pointer of type atomic_t
	* @a: the amount to add to v...
	* @u: ...unless v is equal to u.
	*
	* Atomically adds @a to @v, so long as it was not @u.
	* Returns non-zero if @v was not @u, and zero otherwise.
	*/
	static inline int atomic_add_unless(atomic_t *v, int a, int u)
	{
	int c, old;
	c = atomic_read(v);
	for (;;) {
	if (unlikely(c == (u)))
	break;
	old = atomic_cmpxchg((v), c, c + (a));
	if (likely(old == c))
	break;
	c = old;
	}
	return c != (u);
	}

	#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

	/**
	* atomic64_add_unless - add unless the number is a given value
	* @v: pointer of type atomic64_t
	* @a: the amount to add to v...
	* @u: ...unless v is equal to u.
	*
	* Atomically adds @a to @v, so long as it was not @u.
	* Returns non-zero if @v was not @u, and zero otherwise.
	*/
	static inline int atomic64_add_unless(atomic64_t *v, long a, long u)
	{
	long c, old;
	c = atomic64_read(v);
	for (;;) {
	if (unlikely(c == (u)))
	break;
	old = atomic64_cmpxchg((v), c, c + (a));
	if (likely(old == c))
	break;
	c = old;
	}
	return c != (u);
	}

	#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)

	/* These are x86-specific, used by some header files */
	#define atomic_clear_mask(mask, addr) \
	asm volatile(LOCK_PREFIX "andl %0,%1" \
	: : "r" (~(mask)), "m" (*(addr)) : "memory")

	#define atomic_set_mask(mask, addr) \
	asm volatile(LOCK_PREFIX "orl %0,%1" \
	: : "r" ((unsigned)(mask)), "m" (*(addr)) \
	: "memory")

	/* Atomic operations are already serializing on x86 */
	#define smp_mb__before_atomic_dec() barrier()
	#define smp_mb__after_atomic_dec() barrier()
	#define smp_mb__before_atomic_inc() barrier()
	#define smp_mb__after_atomic_inc() barrier()

	#include <asm-generic/atomic.h>
	#endif