75 lines
2.0 KiB
C
75 lines
2.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SEM_H
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#define _LINUX_SEM_H
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#include <linux/atomic.h>
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#include <linux/rcupdate.h>
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#include <linux/cache.h>
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#include <linux/time64.h>
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#include <uapi/linux/sem.h>
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struct task_struct;
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/* One semaphore structure for each semaphore in the system. */
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struct sem {
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int semval; /* current value */
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/*
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* PID of the process that last modified the semaphore. For
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* Linux, specifically these are:
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* - semop
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* - semctl, via SETVAL and SETALL.
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* - at task exit when performing undo adjustments (see exit_sem).
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*/
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int sempid;
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spinlock_t lock; /* spinlock for fine-grained semtimedop */
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struct list_head pending_alter; /* pending single-sop operations */
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/* that alter the semaphore */
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struct list_head pending_const; /* pending single-sop operations */
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/* that do not alter the semaphore*/
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time_t sem_otime; /* candidate for sem_otime */
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} ____cacheline_aligned_in_smp;
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/* One sem_array data structure for each set of semaphores in the system. */
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struct sem_array {
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struct kern_ipc_perm sem_perm; /* permissions .. see ipc.h */
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time64_t sem_ctime; /* create/last semctl() time */
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struct list_head pending_alter; /* pending operations */
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/* that alter the array */
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struct list_head pending_const; /* pending complex operations */
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/* that do not alter semvals */
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struct list_head list_id; /* undo requests on this array */
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int sem_nsems; /* no. of semaphores in array */
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int complex_count; /* pending complex operations */
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unsigned int use_global_lock;/* >0: global lock required */
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struct sem sems[];
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} __randomize_layout;
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#ifdef CONFIG_SYSVIPC
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struct sysv_sem {
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struct sem_undo_list *undo_list;
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};
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extern int copy_semundo(unsigned long clone_flags, struct task_struct *tsk);
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extern void exit_sem(struct task_struct *tsk);
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#else
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struct sysv_sem {
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/* empty */
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};
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static inline int copy_semundo(unsigned long clone_flags, struct task_struct *tsk)
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{
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return 0;
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}
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static inline void exit_sem(struct task_struct *tsk)
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{
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return;
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}
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#endif
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#endif /* _LINUX_SEM_H */
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