Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_SEM_H
3#define _LINUX_SEM_H
4
5#include <linux/atomic.h>
6#include <linux/rcupdate.h>
7#include <linux/cache.h>
8#include <linux/time64.h>
9#include <uapi/linux/sem.h>
10
11struct task_struct;
12
13/* One semaphore structure for each semaphore in the system. */
14struct sem {
15 int semval; /* current value */
16 /*
17 * PID of the process that last modified the semaphore. For
18 * Linux, specifically these are:
19 * - semop
20 * - semctl, via SETVAL and SETALL.
21 * - at task exit when performing undo adjustments (see exit_sem).
22 */
23 int sempid;
24 spinlock_t lock; /* spinlock for fine-grained semtimedop */
25 struct list_head pending_alter; /* pending single-sop operations */
26 /* that alter the semaphore */
27 struct list_head pending_const; /* pending single-sop operations */
28 /* that do not alter the semaphore*/
29 time_t sem_otime; /* candidate for sem_otime */
30} ____cacheline_aligned_in_smp;
31
32/* One sem_array data structure for each set of semaphores in the system. */
33struct sem_array {
34 struct kern_ipc_perm sem_perm; /* permissions .. see ipc.h */
35 time64_t sem_ctime; /* create/last semctl() time */
36 struct list_head pending_alter; /* pending operations */
37 /* that alter the array */
38 struct list_head pending_const; /* pending complex operations */
39 /* that do not alter semvals */
40 struct list_head list_id; /* undo requests on this array */
41 int sem_nsems; /* no. of semaphores in array */
42 int complex_count; /* pending complex operations */
43 unsigned int use_global_lock;/* >0: global lock required */
44
45 struct sem sems[];
46} __randomize_layout;
47
48#ifdef CONFIG_SYSVIPC
49
50struct sysv_sem {
51 struct sem_undo_list *undo_list;
52};
53
54extern int copy_semundo(unsigned long clone_flags, struct task_struct *tsk);
55extern void exit_sem(struct task_struct *tsk);
56
57#else
58
59struct sysv_sem {
60 /* empty */
61};
62
63static inline int copy_semundo(unsigned long clone_flags, struct task_struct *tsk)
64{
65 return 0;
66}
67
68static inline void exit_sem(struct task_struct *tsk)
69{
70 return;
71}
72#endif
73
74#endif /* _LINUX_SEM_H */