Changeset cb10bc9 in mainline for uspace/lib/c/include/futex.h

Timestamp:

2012-12-04T02:21:03Z (12 years ago)

Author:

Adam Hraska <adam.hraska+hos@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

1b7eec9

Parents:

927a181e

Message:

Inlined uspace futex functions.

File:

• uspace/lib/c/include/futex.h (modified) (2 diffs)

uspace/lib/c/include/futex.h

@@ -38 +38 @@
 #include <atomic.h>
 #include <sys/types.h>
+#include <libc.h>
+
 
 #define FUTEX_INITIALIZER  {{1}}
@@ -45 +47 @@
 } futex_t;
 
+
 extern void futex_initialize(futex_t *futex, int value);
-extern int futex_down(futex_t *futex);
-extern int futex_trydown(futex_t *futex);
-extern int futex_up(futex_t *futex);
+
+#define futex_down(fut)     (void)_futex_down((fut))
+#define futex_trydown(fut)  _futex_trydown((fut))
+#define futex_up(fut)       (void)_futex_up((fut))
+
+
+/** Try to down the futex.
+ *
+ * @param futex Futex.
+ *
+ * @return Non-zero if the futex was acquired.
+ * @return Zero if the futex was not acquired.
+ *
+ */
+static inline int _futex_trydown(futex_t *futex)
+{
+        return cas(&futex->val, 1, 0);
+}
+
+/** Down the futex.
+ *
+ * @param futex Futex.
+ *
+ * @return ENOENT if there is no such virtual address.
+ * @return Zero in the uncontended case.
+ * @return Otherwise one of ESYNCH_OK_ATOMIC or ESYNCH_OK_BLOCKED.
+ *
+ */
+static inline int _futex_down(futex_t *futex)
+{
+        if ((atomic_signed_t) atomic_predec(&futex->val) < 0)
+                return __SYSCALL1(SYS_FUTEX_SLEEP, (sysarg_t) &futex->val.count);
+        
+        return 0;
+}
+
+/** Up the futex.
+ *
+ * @param futex Futex.
+ *
+ * @return ENOENT if there is no such virtual address.
+ * @return Zero in the uncontended case.
+ *
+ */
+static inline int _futex_up(futex_t *futex)
+{
+        if ((atomic_signed_t) atomic_postinc(&futex->val) < 0)
+                return __SYSCALL1(SYS_FUTEX_WAKEUP, (sysarg_t) &futex->val.count);
+        
+        return 0;
+}
 
 #endif