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

#ifndef _LINUX_FUTEX_H
#define _LINUX_FUTEX_H

#include <uapi/linux/futex.h>

struct inode;
struct mm_struct;
struct task_struct;
union ktime;

long do_futex(u32 __user *uaddr, int op, u32 val, union ktime *timeout,
	      u32 __user *uaddr2, u32 val2, u32 val3);

extern int
handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi);

/*
 * Futexes are matched on equal values of this key.
 * The key type depends on whether it's a shared or private mapping.
 * Don't rearrange members without looking at hash_futex().
 *
 * offset is aligned to a multiple of sizeof(u32) (== 4) by definition.
 * We use the two low order bits of offset to tell what is the kind of key :
 *  00 : Private process futex (PTHREAD_PROCESS_PRIVATE)
 *       (no reference on an inode or mm)
 *  01 : Shared futex (PTHREAD_PROCESS_SHARED)
 *	mapped on a file (reference on the underlying inode)
 *  10 : Shared futex (PTHREAD_PROCESS_SHARED)
 *       (but private mapping on an mm, and reference taken on it)
*/

#define FUT_OFF_INODE    1 /* We set bit 0 if key has a reference on inode */
#define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */

union futex_key {
	struct {
		unsigned long pgoff;
		struct inode *inode;
		int offset;
	} shared;
	struct {
		unsigned long address;
		struct mm_struct *mm;
		int offset;
	} private;
	struct {
		unsigned long word;
		void *ptr;
		int offset;
	} both;
};

#define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = NULL } }

#ifdef CONFIG_FUTEX
extern void exit_robust_list(struct task_struct *curr);
extern void exit_pi_state_list(struct task_struct *curr);
extern int futex_cmpxchg_enabled;
#else
static inline void exit_robust_list(struct task_struct *curr)
{
}
static inline void exit_pi_state_list(struct task_struct *curr)
{
}
#endif
#endif
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_FUTEX_H
	2	#define _LINUX_FUTEX_H
	3
607ca46e	4	#include <uapi/linux/futex.h>
0771dfef	5
9064a678 MF	6	struct inode;
	7	struct mm_struct;
	8	struct task_struct;
	9	union ktime;
	10
c19384b5	11	long do_futex(u32 __user uaddr, int op, u32 val, union ktime timeout,
e2970f2f	12	u32 __user *uaddr2, u32 val2, u32 val3);
1da177e4	13
e3f2ddea IM	14	extern int
e3f2ddea IM	15	handle_futex_death(u32 __user uaddr, struct task_struct curr, int pi);
0771dfef	16
9adef58b RR	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.
34f01cc1 ED	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
9adef58b RR	35	union 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	};
9adef58b	52
38d47c1b PZ	53	#define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = NULL } }
38d47c1b PZ	54
0771dfef IM	55	#ifdef CONFIG_FUTEX
0771dfef IM	56	extern void exit_robust_list(struct task_struct *curr);
c87e2837	57	extern void exit_pi_state_list(struct task_struct *curr);
a0c1e907	58	extern int futex_cmpxchg_enabled;
0771dfef IM	59	#else
	60	static inline void exit_robust_list(struct task_struct *curr)
	61	{
	62	}
c87e2837 IM	63	static inline void exit_pi_state_list(struct task_struct *curr)
	64	{
	65	}
0771dfef	66	#endif
1da177e4	67	#endif