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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-06-10 05:30:17 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-06-10 05:30:17 -0300
commitd635711daa98be86d4c7fd01499c34f566b54ccb (patch)
treeaa5cc3760a27c3d57146498cb82fa549547de06c /include/linux/atomic.h
parentc91265cd0efb83778f015b4d4b1129bd2cfd075e (diff)
Linux-libre 4.6.2-gnu
Diffstat (limited to 'include/linux/atomic.h')
-rw-r--r--include/linux/atomic.h31
1 files changed, 31 insertions, 0 deletions
diff --git a/include/linux/atomic.h b/include/linux/atomic.h
index 301de78d6..506c35318 100644
--- a/include/linux/atomic.h
+++ b/include/linux/atomic.h
@@ -34,20 +34,29 @@
* The idea here is to build acquire/release variants by adding explicit
* barriers on top of the relaxed variant. In the case where the relaxed
* variant is already fully ordered, no additional barriers are needed.
+ *
+ * Besides, if an arch has a special barrier for acquire/release, it could
+ * implement its own __atomic_op_* and use the same framework for building
+ * variants
*/
+#ifndef __atomic_op_acquire
#define __atomic_op_acquire(op, args...) \
({ \
typeof(op##_relaxed(args)) __ret = op##_relaxed(args); \
smp_mb__after_atomic(); \
__ret; \
})
+#endif
+#ifndef __atomic_op_release
#define __atomic_op_release(op, args...) \
({ \
smp_mb__before_atomic(); \
op##_relaxed(args); \
})
+#endif
+#ifndef __atomic_op_fence
#define __atomic_op_fence(op, args...) \
({ \
typeof(op##_relaxed(args)) __ret; \
@@ -56,6 +65,7 @@
smp_mb__after_atomic(); \
__ret; \
})
+#endif
/* atomic_add_return_relaxed */
#ifndef atomic_add_return_relaxed
@@ -548,6 +558,27 @@ static inline int atomic_dec_if_positive(atomic_t *v)
}
#endif
+/**
+ * atomic_fetch_or - perform *p |= mask and return old value of *p
+ * @p: pointer to atomic_t
+ * @mask: mask to OR on the atomic_t
+ */
+#ifndef atomic_fetch_or
+static inline int atomic_fetch_or(atomic_t *p, int mask)
+{
+ int old, val = atomic_read(p);
+
+ for (;;) {
+ old = atomic_cmpxchg(p, val, val | mask);
+ if (old == val)
+ break;
+ val = old;
+ }
+
+ return old;
+}
+#endif
+
#ifdef CONFIG_GENERIC_ATOMIC64
#include <asm-generic/atomic64.h>
#endif