sem.h

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#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 sem_array data structure for each set of semaphores in the system. */
struct sem_array {
    struct kern_ipc_perm    ____cacheline_aligned_in_smp
                sem_perm;   /* permissions .. see ipc.h */
    time_t          sem_otime;  /* last semop time */
    time_t          sem_ctime;  /* last change time */
    struct sem      *sem_base;  /* ptr to first semaphore in array */
    struct list_head    sem_pending;    /* pending operations to be processed */
    struct list_head    list_id;    /* undo requests on this array */
    int         sem_nsems;  /* no. of semaphores in array */
    int         complex_count;  /* pending complex operations */
};

#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 */