1#ifndef _LINUX_FUTEX_H
2#define _LINUX_FUTEX_H
3
4#include <uapi/linux/futex.h>
5
6struct inode;
7struct mm_struct;
8struct task_struct;
9union ktime;
10
11long do_futex(u32 __user *uaddr, int op, u32 val, union ktime *timeout,
12	      u32 __user *uaddr2, u32 val2, u32 val3);
13
14extern int
15handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi);
16
17/*
18 * Futexes are matched on equal values of this key.
19 * The key type depends on whether it's a shared or private mapping.
20 * Don't rearrange members without looking at hash_futex().
21 *
22 * offset is aligned to a multiple of sizeof(u32) (== 4) by definition.
23 * We use the two low order bits of offset to tell what is the kind of key :
24 *  00 : Private process futex (PTHREAD_PROCESS_PRIVATE)
25 *       (no reference on an inode or mm)
26 *  01 : Shared futex (PTHREAD_PROCESS_SHARED)
27 *	mapped on a file (reference on the underlying inode)
28 *  10 : Shared futex (PTHREAD_PROCESS_SHARED)
29 *       (but private mapping on an mm, and reference taken on it)
30*/
31
32#define FUT_OFF_INODE    1 /* We set bit 0 if key has a reference on inode */
33#define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */
34
35union futex_key {
36	struct {
37		unsigned long pgoff;
38		struct inode *inode;
39		int offset;
40	} shared;
41	struct {
42		unsigned long address;
43		struct mm_struct *mm;
44		int offset;
45	} private;
46	struct {
47		unsigned long word;
48		void *ptr;
49		int offset;
50	} both;
51};
52
53#define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = NULL } }
54
55#ifdef CONFIG_FUTEX
56extern void exit_robust_list(struct task_struct *curr);
57extern void exit_pi_state_list(struct task_struct *curr);
58#ifdef CONFIG_HAVE_FUTEX_CMPXCHG
59#define futex_cmpxchg_enabled 1
60#else
61extern int futex_cmpxchg_enabled;
62#endif
63#else
64static inline void exit_robust_list(struct task_struct *curr)
65{
66}
67static inline void exit_pi_state_list(struct task_struct *curr)
68{
69}
70#endif
71#endif
72