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

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_FUTEX_H
#define _LINUX_FUTEX_H

#include <linux/ktime.h>
#include <uapi/linux/futex.h>

struct inode;
struct mm_struct;
struct task_struct;

/*
 * 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);

long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
	      u32 __user *uaddr2, u32 val2, u32 val3);
#else
static inline void exit_robust_list(struct task_struct *curr)
{
}

static inline long do_futex(u32 __user *uaddr, int op, u32 val,
			    ktime_t *timeout, u32 __user *uaddr2,
			    u32 val2, u32 val3)
{
	return -EINVAL;
}
#endif

#ifdef CONFIG_FUTEX_PI
extern void exit_pi_state_list(struct task_struct *curr);
#else
static inline void exit_pi_state_list(struct task_struct *curr)
{
}
#endif

#endif
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1da177e4 LT	2	#ifndef _LINUX_FUTEX_H
	3	#define _LINUX_FUTEX_H
	4
2456e855	5	#include <linux/ktime.h>
607ca46e	6	#include <uapi/linux/futex.h>
0771dfef	7
9064a678 MF	8	struct inode;
	9	struct mm_struct;
	10	struct task_struct;
9064a678	11
9adef58b RR	12	/*
	13	* Futexes are matched on equal values of this key.
	14	* The key type depends on whether it's a shared or private mapping.
	15	* Don't rearrange members without looking at hash_futex().
	16	*
	17	* offset is aligned to a multiple of sizeof(u32) (== 4) by definition.
34f01cc1 ED	18	* We use the two low order bits of offset to tell what is the kind of key :
	19	* 00 : Private process futex (PTHREAD_PROCESS_PRIVATE)
	20	* (no reference on an inode or mm)
	21	* 01 : Shared futex (PTHREAD_PROCESS_SHARED)
	22	* mapped on a file (reference on the underlying inode)
	23	* 10 : Shared futex (PTHREAD_PROCESS_SHARED)
	24	* (but private mapping on an mm, and reference taken on it)
	25	*/
	26
	27	#define FUT_OFF_INODE 1 /* We set bit 0 if key has a reference on inode */
	28	#define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */
	29
9adef58b RR	30	union futex_key {
	31	struct {
	32	unsigned long pgoff;
	33	struct inode *inode;
	34	int offset;
	35	} shared;
	36	struct {
	37	unsigned long address;
	38	struct mm_struct *mm;
	39	int offset;
	40	} private;
	41	struct {
	42	unsigned long word;
	43	void *ptr;
	44	int offset;
	45	} both;
	46	};
9adef58b	47
38d47c1b PZ	48	#define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = NULL } }
38d47c1b PZ	49
0771dfef IM	50	#ifdef CONFIG_FUTEX
0771dfef IM	51	extern void exit_robust_list(struct task_struct *curr);
2de0db99 DB	52
	53	long do_futex(u32 __user uaddr, int op, u32 val, ktime_t timeout,
	54	u32 __user *uaddr2, u32 val2, u32 val3);
0771dfef IM	55	#else
	56	static inline void exit_robust_list(struct task_struct *curr)
	57	{
	58	}
2de0db99 DB	59
	60	static inline long do_futex(u32 __user *uaddr, int op, u32 val,
	61	ktime_t timeout, u32 __user uaddr2,
	62	u32 val2, u32 val3)
	63	{
	64	return -EINVAL;
	65	}
bc2eecd7 NP	66	#endif
	67
	68	#ifdef CONFIG_FUTEX_PI
	69	extern void exit_pi_state_list(struct task_struct *curr);
	70	#else
c87e2837 IM	71	static inline void exit_pi_state_list(struct task_struct *curr)
	72	{
	73	}
0771dfef	74	#endif
bc2eecd7	75
1da177e4	76	#endif