[mirror_ubuntu-artful-kernel.git] / include / linux / sem.h

#ifndef _LINUX_SEM_H
#define _LINUX_SEM_H

#include <linux/atomic.h>
#include <linux/rcupdate.h>
#include <linux/cache.h>
#include <uapi/linux/sem.h>

struct task_struct;

/* One semaphore structure for each semaphore in the system. */
struct sem {
	int	semval;		/* current value */
	/*
	 * PID of the process that last modified the semaphore. For
	 * Linux, specifically these are:
	 *  - semop
	 *  - semctl, via SETVAL and SETALL.
	 *  - at task exit when performing undo adjustments (see exit_sem).
	 */
	int	sempid;
	spinlock_t	lock;	/* spinlock for fine-grained semtimedop */
	struct list_head pending_alter; /* pending single-sop operations */
					/* that alter the semaphore */
	struct list_head pending_const; /* pending single-sop operations */
					/* that do not alter the semaphore*/
	time_t	sem_otime;	/* candidate for sem_otime */
} ____cacheline_aligned_in_smp;

/* One sem_array data structure for each set of semaphores in the system. */
struct sem_array {
	struct kern_ipc_perm	sem_perm;	/* permissions .. see ipc.h */
	time_t			sem_ctime;	/* create/last semctl() time */
	struct list_head	pending_alter;	/* pending operations */
						/* that alter the array */
	struct list_head	pending_const;	/* pending complex operations */
						/* that do not alter semvals */
	struct list_head	list_id;	/* undo requests on this array */
	int			sem_nsems;	/* no. of semaphores in array */
	int			complex_count;	/* pending complex operations */
	unsigned int		use_global_lock;/* >0: global lock required */

	struct sem		sems[];
} __randomize_layout;

#ifdef CONFIG_SYSVIPC

struct sysv_sem {
	struct sem_undo_list *undo_list;
};

extern int copy_semundo(unsigned long clone_flags, struct task_struct *tsk);
extern void exit_sem(struct task_struct *tsk);

#else

struct sysv_sem {
	/* empty */
};

static inline int copy_semundo(unsigned long clone_flags, struct task_struct *tsk)
{
	return 0;
}

static inline void exit_sem(struct task_struct *tsk)
{
	return;
}
#endif

#endif /* _LINUX_SEM_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_SEM_H
	2	#define _LINUX_SEM_H
	3
60063497	4	#include <linux/atomic.h>
380af1b3	5	#include <linux/rcupdate.h>
31a7c474	6	#include <linux/cache.h>
607ca46e	7	#include <uapi/linux/sem.h>
1da177e4	8
8c65b4a6 TS	9	struct task_struct;
8c65b4a6 TS	10
1a233956 MS	11	/* One semaphore structure for each semaphore in the system. */
	12	struct sem {
	13	int semval; /* current value */
	14	/*
	15	* PID of the process that last modified the semaphore. For
	16	* Linux, specifically these are:
	17	* - semop
	18	* - semctl, via SETVAL and SETALL.
	19	* - at task exit when performing undo adjustments (see exit_sem).
	20	*/
	21	int sempid;
	22	spinlock_t lock; /* spinlock for fine-grained semtimedop */
	23	struct list_head pending_alter; /* pending single-sop operations */
	24	/* that alter the semaphore */
	25	struct list_head pending_const; /* pending single-sop operations */
	26	/* that do not alter the semaphore*/
	27	time_t sem_otime; /* candidate for sem_otime */
	28	} ____cacheline_aligned_in_smp;
	29
1da177e4 LT	30	/* One sem_array data structure for each set of semaphores in the system. */
1da177e4 LT	31	struct sem_array {
60f3e00d	32	struct kern_ipc_perm sem_perm; /* permissions .. see ipc.h */
2cd648c1	33	time_t sem_ctime; /* create/last semctl() time */
1a82e9e1 MS	34	struct list_head pending_alter; /* pending operations */
	35	/* that alter the array */
	36	struct list_head pending_const; /* pending complex operations */
	37	/* that do not alter semvals */
4daa28f6	38	struct list_head list_id; /* undo requests on this array */
b97e820f MS	39	int sem_nsems; /* no. of semaphores in array */
b97e820f MS	40	int complex_count; /* pending complex operations */
9de5ab8a	41	unsigned int use_global_lock;/* >0: global lock required */
1a233956 MS	42
1a233956 MS	43	struct sem sems[];
3859a271	44	} __randomize_layout;
1da177e4	45
f567a185 MS	46	#ifdef CONFIG_SYSVIPC
f567a185 MS	47
1da177e4 LT	48	struct sysv_sem {
	49	struct sem_undo_list *undo_list;
	50	};
	51
1da177e4 LT	52	extern int copy_semundo(unsigned long clone_flags, struct task_struct *tsk);
	53	extern void exit_sem(struct task_struct *tsk);
	54
	55	#else
f567a185 MS	56
	57	struct sysv_sem {
	58	/* empty */
	59	};
	60
1da177e4 LT	61	static inline int copy_semundo(unsigned long clone_flags, struct task_struct *tsk)
	62	{
	63	return 0;
	64	}
	65
	66	static inline void exit_sem(struct task_struct *tsk)
	67	{
	68	return;
	69	}
	70	#endif
	71
1da177e4	72	#endif /* _LINUX_SEM_H */