~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/include/asm-generic/atomic.h

Version: ~ [ linux-5.11-rc3 ] ~ [ linux-5.10.7 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.89 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.167 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.215 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.251 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.251 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * Generic C implementation of atomic counter operations. Usable on
  3  * UP systems only. Do not include in machine independent code.
  4  *
  5  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
  6  * Written by David Howells (dhowells@redhat.com)
  7  *
  8  * This program is free software; you can redistribute it and/or
  9  * modify it under the terms of the GNU General Public Licence
 10  * as published by the Free Software Foundation; either version
 11  * 2 of the Licence, or (at your option) any later version.
 12  */
 13 #ifndef __ASM_GENERIC_ATOMIC_H
 14 #define __ASM_GENERIC_ATOMIC_H
 15 
 16 #include <asm/cmpxchg.h>
 17 #include <asm/barrier.h>
 18 
 19 /*
 20  * atomic_$op() - $op integer to atomic variable
 21  * @i: integer value to $op
 22  * @v: pointer to the atomic variable
 23  *
 24  * Atomically $ops @i to @v. Does not strictly guarantee a memory-barrier, use
 25  * smp_mb__{before,after}_atomic().
 26  */
 27 
 28 /*
 29  * atomic_$op_return() - $op interer to atomic variable and returns the result
 30  * @i: integer value to $op
 31  * @v: pointer to the atomic variable
 32  *
 33  * Atomically $ops @i to @v. Does imply a full memory barrier.
 34  */
 35 
 36 #ifdef CONFIG_SMP
 37 
 38 /* we can build all atomic primitives from cmpxchg */
 39 
 40 #define ATOMIC_OP(op, c_op)                                             \
 41 static inline void atomic_##op(int i, atomic_t *v)                      \
 42 {                                                                       \
 43         int c, old;                                                     \
 44                                                                         \
 45         c = v->counter;                                                 \
 46         while ((old = cmpxchg(&v->counter, c, c c_op i)) != c)          \
 47                 c = old;                                                \
 48 }
 49 
 50 #define ATOMIC_OP_RETURN(op, c_op)                                      \
 51 static inline int atomic_##op##_return(int i, atomic_t *v)              \
 52 {                                                                       \
 53         int c, old;                                                     \
 54                                                                         \
 55         c = v->counter;                                                 \
 56         while ((old = cmpxchg(&v->counter, c, c c_op i)) != c)          \
 57                 c = old;                                                \
 58                                                                         \
 59         return c c_op i;                                                \
 60 }
 61 
 62 #define ATOMIC_FETCH_OP(op, c_op)                                       \
 63 static inline int atomic_fetch_##op(int i, atomic_t *v)                 \
 64 {                                                                       \
 65         int c, old;                                                     \
 66                                                                         \
 67         c = v->counter;                                                 \
 68         while ((old = cmpxchg(&v->counter, c, c c_op i)) != c)          \
 69                 c = old;                                                \
 70                                                                         \
 71         return c;                                                       \
 72 }
 73 
 74 #else
 75 
 76 #include <linux/irqflags.h>
 77 
 78 #define ATOMIC_OP(op, c_op)                                             \
 79 static inline void atomic_##op(int i, atomic_t *v)                      \
 80 {                                                                       \
 81         unsigned long flags;                                            \
 82                                                                         \
 83         raw_local_irq_save(flags);                                      \
 84         v->counter = v->counter c_op i;                                 \
 85         raw_local_irq_restore(flags);                                   \
 86 }
 87 
 88 #define ATOMIC_OP_RETURN(op, c_op)                                      \
 89 static inline int atomic_##op##_return(int i, atomic_t *v)              \
 90 {                                                                       \
 91         unsigned long flags;                                            \
 92         int ret;                                                        \
 93                                                                         \
 94         raw_local_irq_save(flags);                                      \
 95         ret = (v->counter = v->counter c_op i);                         \
 96         raw_local_irq_restore(flags);                                   \
 97                                                                         \
 98         return ret;                                                     \
 99 }
100 
101 #define ATOMIC_FETCH_OP(op, c_op)                                       \
102 static inline int atomic_fetch_##op(int i, atomic_t *v)                 \
103 {                                                                       \
104         unsigned long flags;                                            \
105         int ret;                                                        \
106                                                                         \
107         raw_local_irq_save(flags);                                      \
108         ret = v->counter;                                               \
109         v->counter = v->counter c_op i;                                 \
110         raw_local_irq_restore(flags);                                   \
111                                                                         \
112         return ret;                                                     \
113 }
114 
115 #endif /* CONFIG_SMP */
116 
117 #ifndef atomic_add_return
118 ATOMIC_OP_RETURN(add, +)
119 #endif
120 
121 #ifndef atomic_sub_return
122 ATOMIC_OP_RETURN(sub, -)
123 #endif
124 
125 #ifndef atomic_fetch_add
126 ATOMIC_FETCH_OP(add, +)
127 #endif
128 
129 #ifndef atomic_fetch_sub
130 ATOMIC_FETCH_OP(sub, -)
131 #endif
132 
133 #ifndef atomic_fetch_and
134 ATOMIC_FETCH_OP(and, &)
135 #endif
136 
137 #ifndef atomic_fetch_or
138 ATOMIC_FETCH_OP(or, |)
139 #endif
140 
141 #ifndef atomic_fetch_xor
142 ATOMIC_FETCH_OP(xor, ^)
143 #endif
144 
145 #ifndef atomic_and
146 ATOMIC_OP(and, &)
147 #endif
148 
149 #ifndef atomic_or
150 ATOMIC_OP(or, |)
151 #endif
152 
153 #ifndef atomic_xor
154 ATOMIC_OP(xor, ^)
155 #endif
156 
157 #undef ATOMIC_FETCH_OP
158 #undef ATOMIC_OP_RETURN
159 #undef ATOMIC_OP
160 
161 /*
162  * Atomic operations that C can't guarantee us.  Useful for
163  * resource counting etc..
164  */
165 
166 #define ATOMIC_INIT(i)  { (i) }
167 
168 /**
169  * atomic_read - read atomic variable
170  * @v: pointer of type atomic_t
171  *
172  * Atomically reads the value of @v.
173  */
174 #ifndef atomic_read
175 #define atomic_read(v)  READ_ONCE((v)->counter)
176 #endif
177 
178 /**
179  * atomic_set - set atomic variable
180  * @v: pointer of type atomic_t
181  * @i: required value
182  *
183  * Atomically sets the value of @v to @i.
184  */
185 #define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
186 
187 #include <linux/irqflags.h>
188 
189 static inline int atomic_add_negative(int i, atomic_t *v)
190 {
191         return atomic_add_return(i, v) < 0;
192 }
193 
194 static inline void atomic_add(int i, atomic_t *v)
195 {
196         atomic_add_return(i, v);
197 }
198 
199 static inline void atomic_sub(int i, atomic_t *v)
200 {
201         atomic_sub_return(i, v);
202 }
203 
204 static inline void atomic_inc(atomic_t *v)
205 {
206         atomic_add_return(1, v);
207 }
208 
209 static inline void atomic_dec(atomic_t *v)
210 {
211         atomic_sub_return(1, v);
212 }
213 
214 #define atomic_dec_return(v)            atomic_sub_return(1, (v))
215 #define atomic_inc_return(v)            atomic_add_return(1, (v))
216 
217 #define atomic_sub_and_test(i, v)       (atomic_sub_return((i), (v)) == 0)
218 #define atomic_dec_and_test(v)          (atomic_dec_return(v) == 0)
219 #define atomic_inc_and_test(v)          (atomic_inc_return(v) == 0)
220 
221 #define atomic_xchg(ptr, v)             (xchg(&(ptr)->counter, (v)))
222 #define atomic_cmpxchg(v, old, new)     (cmpxchg(&((v)->counter), (old), (new)))
223 
224 #ifndef __atomic_add_unless
225 static inline int __atomic_add_unless(atomic_t *v, int a, int u)
226 {
227         int c, old;
228         c = atomic_read(v);
229         while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c)
230                 c = old;
231         return c;
232 }
233 #endif
234 
235 #endif /* __ASM_GENERIC_ATOMIC_H */
236 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp