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