Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / include / linux / atomic.h

diff --git a/kernel/include/linux/atomic.h b/kernel/include/linux/atomic.h
new file mode 100644 (file)
index 0000000..5b08a85
--- /dev/null
+++ b/kernel/include/linux/atomic.h
@@ -0,0 +1,131 @@
+/* Atomic operations usable in machine independent code */
+#ifndef _LINUX_ATOMIC_H
+#define _LINUX_ATOMIC_H
+#include <asm/atomic.h>
+
+/**
+ * atomic_add_unless - add unless the number is already 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 @v was not already @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)
+{
+       return __atomic_add_unless(v, a, u) != u;
+}
+
+/**
+ * atomic_inc_not_zero - increment unless the number is zero
+ * @v: pointer of type atomic_t
+ *
+ * Atomically increments @v by 1, so long as @v is non-zero.
+ * Returns non-zero if @v was non-zero, and zero otherwise.
+ */
+#ifndef atomic_inc_not_zero
+#define atomic_inc_not_zero(v)         atomic_add_unless((v), 1, 0)
+#endif
+
+/**
+ * atomic_inc_not_zero_hint - increment if not null
+ * @v: pointer of type atomic_t
+ * @hint: probable value of the atomic before the increment
+ *
+ * This version of atomic_inc_not_zero() gives a hint of probable
+ * value of the atomic. This helps processor to not read the memory
+ * before doing the atomic read/modify/write cycle, lowering
+ * number of bus transactions on some arches.
+ *
+ * Returns: 0 if increment was not done, 1 otherwise.
+ */
+#ifndef atomic_inc_not_zero_hint
+static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint)
+{
+       int val, c = hint;
+
+       /* sanity test, should be removed by compiler if hint is a constant */
+       if (!hint)
+               return atomic_inc_not_zero(v);
+
+       do {
+               val = atomic_cmpxchg(v, c, c + 1);
+               if (val == c)
+                       return 1;
+               c = val;
+       } while (c);
+
+       return 0;
+}
+#endif
+
+#ifndef atomic_inc_unless_negative
+static inline int atomic_inc_unless_negative(atomic_t *p)
+{
+       int v, v1;
+       for (v = 0; v >= 0; v = v1) {
+               v1 = atomic_cmpxchg(p, v, v + 1);
+               if (likely(v1 == v))
+                       return 1;
+       }
+       return 0;
+}
+#endif
+
+#ifndef atomic_dec_unless_positive
+static inline int atomic_dec_unless_positive(atomic_t *p)
+{
+       int v, v1;
+       for (v = 0; v <= 0; v = v1) {
+               v1 = atomic_cmpxchg(p, v, v - 1);
+               if (likely(v1 == v))
+                       return 1;
+       }
+       return 0;
+}
+#endif
+
+/*
+ * atomic_dec_if_positive - decrement by 1 if old value positive
+ * @v: pointer of type atomic_t
+ *
+ * The function returns the old value of *v minus 1, even if
+ * the atomic variable, v, was not decremented.
+ */
+#ifndef atomic_dec_if_positive
+static inline int atomic_dec_if_positive(atomic_t *v)
+{
+       int c, old, dec;
+       c = atomic_read(v);
+       for (;;) {
+               dec = c - 1;
+               if (unlikely(dec < 0))
+                       break;
+               old = atomic_cmpxchg((v), c, dec);
+               if (likely(old == c))
+                       break;
+               c = old;
+       }
+       return dec;
+}
+#endif
+
+#ifndef CONFIG_ARCH_HAS_ATOMIC_OR
+static inline void atomic_or(int i, atomic_t *v)
+{
+       int old;
+       int new;
+
+       do {
+               old = atomic_read(v);
+               new = old | i;
+       } while (atomic_cmpxchg(v, old, new) != old);
+}
+#endif /* #ifndef CONFIG_ARCH_HAS_ATOMIC_OR */
+
+#include <asm-generic/atomic-long.h>
+#ifdef CONFIG_GENERIC_ATOMIC64
+#include <asm-generic/atomic64.h>
+#endif
+#endif /* _LINUX_ATOMIC_H */