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