284 lines
7.2 KiB
C
Executable File
284 lines
7.2 KiB
C
Executable File
/*
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* Atomic operations that C can't guarantee us. Useful for
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* resource counting etc..
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*
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* But use these as seldom as possible since they are much more slower
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* than regular operations.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1996, 1997, 2000 by Ralf Baechle
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*/
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#ifndef __ASM_ATOMIC_H
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#define __ASM_ATOMIC_H
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#include <linux/config.h>
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typedef struct { volatile int counter; } atomic_t;
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#ifdef __KERNEL__
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#define ATOMIC_INIT(i) { (i) }
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/*
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* atomic_read - read atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically reads the value of @v. Note that the guaranteed
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* useful range of an atomic_t is only 24 bits.
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*/
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#define atomic_read(v) ((v)->counter)
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/*
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* atomic_set - set atomic variable
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* @v: pointer of type atomic_t
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* @i: required value
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*
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* Atomically sets the value of @v to @i. Note that the guaranteed
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* useful range of an atomic_t is only 24 bits.
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*/
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#define atomic_set(v,i) ((v)->counter = (i))
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#ifndef CONFIG_CPU_HAS_LLSC
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#include <asm/system.h>
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/*
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* The MIPS I implementation is only atomic with respect to
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* interrupts. R3000 based multiprocessor machines are rare anyway ...
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*
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* atomic_add - add integer to atomic variable
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* @i: integer value to add
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* @v: pointer of type atomic_t
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*
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* Atomically adds @i to @v. Note that the guaranteed useful range
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* of an atomic_t is only 24 bits.
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*/
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extern __inline__ void atomic_add(int i, atomic_t * v)
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{
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int flags;
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save_flags(flags);
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cli();
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v->counter += i;
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restore_flags(flags);
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}
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/*
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* atomic_sub - subtract the atomic variable
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically subtracts @i from @v. Note that the guaranteed
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* useful range of an atomic_t is only 24 bits.
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*/
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extern __inline__ void atomic_sub(int i, atomic_t * v)
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{
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int flags;
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save_flags(flags);
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cli();
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v->counter -= i;
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restore_flags(flags);
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}
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extern __inline__ int atomic_add_return(int i, atomic_t * v)
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{
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int temp, flags;
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save_flags(flags);
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cli();
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temp = v->counter;
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temp += i;
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v->counter = temp;
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restore_flags(flags);
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return temp;
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}
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extern __inline__ int atomic_sub_return(int i, atomic_t * v)
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{
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int temp, flags;
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save_flags(flags);
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cli();
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temp = v->counter;
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temp -= i;
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v->counter = temp;
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restore_flags(flags);
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return temp;
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}
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#else
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/*
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* ... while for MIPS II and better we can use ll/sc instruction. This
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* implementation is SMP safe ...
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*/
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/*
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* atomic_add - add integer to atomic variable
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* @i: integer value to add
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* @v: pointer of type atomic_t
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*
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* Atomically adds @i to @v. Note that the guaranteed useful range
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* of an atomic_t is only 24 bits.
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*/
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extern __inline__ void atomic_add(int i, atomic_t * v)
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{
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unsigned long temp;
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__asm__ __volatile__(
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"1: ll %0, %1 # atomic_add\n"
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" addu %0, %2 \n"
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" sc %0, %1 \n"
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" beqz %0, 1b \n"
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: "=&r" (temp), "=m" (v->counter)
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: "Ir" (i), "m" (v->counter));
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}
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/*
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* atomic_sub - subtract the atomic variable
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically subtracts @i from @v. Note that the guaranteed
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* useful range of an atomic_t is only 24 bits.
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*/
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extern __inline__ void atomic_sub(int i, atomic_t * v)
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{
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unsigned long temp;
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__asm__ __volatile__(
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"1: ll %0, %1 # atomic_sub\n"
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" subu %0, %2 \n"
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" sc %0, %1 \n"
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" beqz %0, 1b \n"
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: "=&r" (temp), "=m" (v->counter)
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: "Ir" (i), "m" (v->counter));
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}
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/*
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* Same as above, but return the result value
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*/
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extern __inline__ int atomic_add_return(int i, atomic_t * v)
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{
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unsigned long temp, result;
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__asm__ __volatile__(
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".set push # atomic_add_return\n"
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".set noreorder \n"
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"1: ll %1, %2 \n"
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" addu %0, %1, %3 \n"
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" sc %0, %2 \n"
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" beqz %0, 1b \n"
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" addu %0, %1, %3 \n"
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".set pop \n"
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: "=&r" (result), "=&r" (temp), "=m" (v->counter)
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: "Ir" (i), "m" (v->counter)
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: "memory");
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return result;
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}
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extern __inline__ int atomic_sub_return(int i, atomic_t * v)
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{
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unsigned long temp, result;
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__asm__ __volatile__(
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".set push \n"
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".set noreorder # atomic_sub_return\n"
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"1: ll %1, %2 \n"
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" subu %0, %1, %3 \n"
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" sc %0, %2 \n"
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" beqz %0, 1b \n"
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" subu %0, %1, %3 \n"
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".set pop \n"
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: "=&r" (result), "=&r" (temp), "=m" (v->counter)
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: "Ir" (i), "m" (v->counter)
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: "memory");
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return result;
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}
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#endif
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#define atomic_dec_return(v) atomic_sub_return(1,(v))
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#define atomic_inc_return(v) atomic_add_return(1,(v))
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/*
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* atomic_sub_and_test - subtract value from variable and test result
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically subtracts @i from @v and returns
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* true if the result is zero, or false for all
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* other cases. Note that the guaranteed
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* useful range of an atomic_t is only 24 bits.
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*/
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#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
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/*
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* atomic_inc_and_test - increment and test
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1
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* and returns true if the result is zero, or false for all
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* other cases. Note that the guaranteed
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* useful range of an atomic_t is only 24 bits.
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*/
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#define atomic_inc_and_test(v) (atomic_inc_return(1, (v)) == 0)
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/*
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* atomic_dec_and_test - decrement by 1 and test
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* @v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1 and
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* returns true if the result is 0, or false for all other
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* cases. Note that the guaranteed
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* useful range of an atomic_t is only 24 bits.
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*/
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#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
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/*
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* atomic_inc - increment atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1. Note that the guaranteed
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* useful range of an atomic_t is only 24 bits.
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*/
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#define atomic_inc(v) atomic_add(1,(v))
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/*
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* atomic_dec - decrement and test
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* @v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1. Note that the guaranteed
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* useful range of an atomic_t is only 24 bits.
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*/
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#define atomic_dec(v) atomic_sub(1,(v))
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/*
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* atomic_add_negative - add and test if negative
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* @v: pointer of type atomic_t
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* @i: integer value to add
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*
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* Atomically adds @i to @v and returns true
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* if the result is negative, or false when
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* result is greater than or equal to zero. Note that the guaranteed
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* useful range of an atomic_t is only 24 bits.
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*
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* Currently not implemented for MIPS.
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*/
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/* Atomic operations are already serializing */
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#define smp_mb__before_atomic_dec() barrier()
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#define smp_mb__after_atomic_dec() barrier()
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#define smp_mb__before_atomic_inc() barrier()
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#define smp_mb__after_atomic_inc() barrier()
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#endif /* defined(__KERNEL__) */
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#endif /* __ASM_ATOMIC_H */
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