xref: /linux-6.15/include/linux/shm.h (revision bb7e5ce7)
1 #ifndef _LINUX_SHM_H_
2 #define _LINUX_SHM_H_
3 
4 #include <linux/list.h>
5 #include <asm/page.h>
6 #include <uapi/linux/shm.h>
7 #include <asm/shmparam.h>
8 
9 struct shmid_kernel /* private to the kernel */
10 {
11 	struct kern_ipc_perm	shm_perm;
12 	struct file		*shm_file;
13 	unsigned long		shm_nattch;
14 	unsigned long		shm_segsz;
15 	time64_t		shm_atim;
16 	time64_t		shm_dtim;
17 	time64_t		shm_ctim;
18 	pid_t			shm_cprid;
19 	pid_t			shm_lprid;
20 	struct user_struct	*mlock_user;
21 
22 	/* The task created the shm object.  NULL if the task is dead. */
23 	struct task_struct	*shm_creator;
24 	struct list_head	shm_clist;	/* list by creator */
25 } __randomize_layout;
26 
27 /* shm_mode upper byte flags */
28 #define	SHM_DEST	01000	/* segment will be destroyed on last detach */
29 #define SHM_LOCKED      02000   /* segment will not be swapped */
30 
31 #ifdef CONFIG_SYSVIPC
32 struct sysv_shm {
33 	struct list_head shm_clist;
34 };
35 
36 long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr,
37 	      unsigned long shmlba);
38 bool is_file_shm_hugepages(struct file *file);
39 void exit_shm(struct task_struct *task);
40 #define shm_init_task(task) INIT_LIST_HEAD(&(task)->sysvshm.shm_clist)
41 #else
42 struct sysv_shm {
43 	/* empty */
44 };
45 
46 static inline long do_shmat(int shmid, char __user *shmaddr,
47 			    int shmflg, unsigned long *addr,
48 			    unsigned long shmlba)
49 {
50 	return -ENOSYS;
51 }
52 static inline bool is_file_shm_hugepages(struct file *file)
53 {
54 	return false;
55 }
56 static inline void exit_shm(struct task_struct *task)
57 {
58 }
59 static inline void shm_init_task(struct task_struct *task)
60 {
61 }
62 #endif
63 
64 #endif /* _LINUX_SHM_H_ */
65