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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SEM_H
#define _LINUX_SEM_H
#include <linux/atomic.h>
#include <linux/rcupdate.h>
#include <linux/cache.h>
#include <linux/time64.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 */
time64_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 */
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