fedora core 6 1.2949 + vserver 2.2.0

[linux-2.6.git] / include / linux / futex.h

diff --git a/include/linux/futex.h b/include/linux/futex.h
index 10f96c3..3f153b4 100644 (file)
--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -1,6 +1,8 @@
 #ifndef _LINUX_FUTEX_H
 #define _LINUX_FUTEX_H
 
+#include <linux/sched.h>
+
 /* Second argument to futex syscall */
 
 
@@ -10,10 +12,106 @@
 #define FUTEX_REQUEUE          3
 #define FUTEX_CMP_REQUEUE      4
 #define FUTEX_WAKE_OP          5
+#define FUTEX_LOCK_PI          6
+#define FUTEX_UNLOCK_PI                7
+#define FUTEX_TRYLOCK_PI       8
+
+/*
+ * Support for robust futexes: the kernel cleans up held futexes at
+ * thread exit time.
+ */
+
+/*
+ * Per-lock list entry - embedded in user-space locks, somewhere close
+ * to the futex field. (Note: user-space uses a double-linked list to
+ * achieve O(1) list add and remove, but the kernel only needs to know
+ * about the forward link)
+ *
+ * NOTE: this structure is part of the syscall ABI, and must not be
+ * changed.
+ */
+struct robust_list {
+       struct robust_list __user *next;
+};
+
+/*
+ * Per-thread list head:
+ *
+ * NOTE: this structure is part of the syscall ABI, and must only be
+ * changed if the change is first communicated with the glibc folks.
+ * (When an incompatible change is done, we'll increase the structure
+ *  size, which glibc will detect)
+ */
+struct robust_list_head {
+       /*
+        * The head of the list. Points back to itself if empty:
+        */
+       struct robust_list list;
+
+       /*
+        * This relative offset is set by user-space, it gives the kernel
+        * the relative position of the futex field to examine. This way
+        * we keep userspace flexible, to freely shape its data-structure,
+        * without hardcoding any particular offset into the kernel:
+        */
+       long futex_offset;
+
+       /*
+        * The death of the thread may race with userspace setting
+        * up a lock's links. So to handle this race, userspace first
+        * sets this field to the address of the to-be-taken lock,
+        * then does the lock acquire, and then adds itself to the
+        * list, and then clears this field. Hence the kernel will
+        * always have full knowledge of all locks that the thread
+        * _might_ have taken. We check the owner TID in any case,
+        * so only truly owned locks will be handled.
+        */
+       struct robust_list __user *list_op_pending;
+};
+
+/*
+ * Are there any waiters for this robust futex:
+ */
+#define FUTEX_WAITERS          0x80000000
 
-long do_futex(unsigned long uaddr, int op, int val,
-               unsigned long timeout, unsigned long uaddr2, int val2,
-               int val3);
+/*
+ * The kernel signals via this bit that a thread holding a futex
+ * has exited without unlocking the futex. The kernel also does
+ * a FUTEX_WAKE on such futexes, after setting the bit, to wake
+ * up any possible waiters:
+ */
+#define FUTEX_OWNER_DIED       0x40000000
+
+/*
+ * The rest of the robust-futex field is for the TID:
+ */
+#define FUTEX_TID_MASK         0x3fffffff
+
+/*
+ * This limit protects against a deliberately circular list.
+ * (Not worth introducing an rlimit for it)
+ */
+#define ROBUST_LIST_LIMIT      2048
+
+#ifdef __KERNEL__
+long do_futex(u32 __user *uaddr, int op, u32 val, unsigned long timeout,
+             u32 __user *uaddr2, u32 val2, u32 val3);
+
+extern int
+handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi);
+
+#ifdef CONFIG_FUTEX
+extern void exit_robust_list(struct task_struct *curr);
+extern void exit_pi_state_list(struct task_struct *curr);
+#else
+static inline void exit_robust_list(struct task_struct *curr)
+{
+}
+static inline void exit_pi_state_list(struct task_struct *curr)
+{
+}
+#endif
+#endif /* __KERNEL__ */
 
 #define FUTEX_OP_SET           0       /* *(int *)UADDR2 = OPARG; */
 #define FUTEX_OP_ADD           1       /* *(int *)UADDR2 += OPARG; */