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authorRussell King <rmk+kernel@arm.linux.org.uk>2015-07-07 12:35:33 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2015-07-07 12:35:33 +0100
commit06be5eefe1192eb8ce8d07497f67595b6bfe9741 (patch)
tree80f1987d4970f8079681f8be0c135cafc8d6329a /tools/include/asm-generic/atomic-gcc.h
parentARM: fix lockdep unannotated irqs-off warning (diff)
parentARM: avoid unwanted GCC memset()/memcpy() optimisations for IO variants (diff)
downloadlinux-dev-06be5eefe1192eb8ce8d07497f67595b6bfe9741.tar.xz
linux-dev-06be5eefe1192eb8ce8d07497f67595b6bfe9741.zip
Merge branches 'fixes' and 'ioremap' into for-linus
Diffstat (limited to 'tools/include/asm-generic/atomic-gcc.h')
-rw-r--r--tools/include/asm-generic/atomic-gcc.h63
1 files changed, 63 insertions, 0 deletions
diff --git a/tools/include/asm-generic/atomic-gcc.h b/tools/include/asm-generic/atomic-gcc.h
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index 000000000000..2ba78c9f5701
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+++ b/tools/include/asm-generic/atomic-gcc.h
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+#ifndef __TOOLS_ASM_GENERIC_ATOMIC_H
+#define __TOOLS_ASM_GENERIC_ATOMIC_H
+
+#include <linux/compiler.h>
+#include <linux/types.h>
+
+/*
+ * Atomic operations that C can't guarantee us. Useful for
+ * resource counting etc..
+ *
+ * Excerpts obtained from the Linux kernel sources.
+ */
+
+#define ATOMIC_INIT(i) { (i) }
+
+/**
+ * atomic_read - read atomic variable
+ * @v: pointer of type atomic_t
+ *
+ * Atomically reads the value of @v.
+ */
+static inline int atomic_read(const atomic_t *v)
+{
+ return ACCESS_ONCE((v)->counter);
+}
+
+/**
+ * atomic_set - set atomic variable
+ * @v: pointer of type atomic_t
+ * @i: required value
+ *
+ * Atomically sets the value of @v to @i.
+ */
+static inline void atomic_set(atomic_t *v, int i)
+{
+ v->counter = i;
+}
+
+/**
+ * atomic_inc - increment atomic variable
+ * @v: pointer of type atomic_t
+ *
+ * Atomically increments @v by 1.
+ */
+static inline void atomic_inc(atomic_t *v)
+{
+ __sync_add_and_fetch(&v->counter, 1);
+}
+
+/**
+ * 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)
+{
+ return __sync_sub_and_fetch(&v->counter, 1) == 0;
+}
+
+#endif /* __TOOLS_ASM_GENERIC_ATOMIC_H */