xref: /linux-6.15/include/linux/shm.h (revision 6fa79bca)
1 #ifndef _LINUX_SHM_H_
2 #define _LINUX_SHM_H_
3 
4 #include <asm/page.h>
5 #include <uapi/linux/shm.h>
6 
7 #define SHMALL (SHMMAX/PAGE_SIZE*(SHMMNI/16)) /* max shm system wide (pages) */
8 #include <asm/shmparam.h>
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 	time_t			shm_atim;
16 	time_t			shm_dtim;
17 	time_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 };
25 
26 /* shm_mode upper byte flags */
27 #define	SHM_DEST	01000	/* segment will be destroyed on last detach */
28 #define SHM_LOCKED      02000   /* segment will not be swapped */
29 #define SHM_HUGETLB     04000   /* segment will use huge TLB pages */
30 #define SHM_NORESERVE   010000  /* don't check for reservations */
31 
32 #ifdef CONFIG_SYSVIPC
33 long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr,
34 	      unsigned long shmlba);
35 extern int is_file_shm_hugepages(struct file *file);
36 extern void exit_shm(struct task_struct *task);
37 #else
38 static inline long do_shmat(int shmid, char __user *shmaddr,
39 			    int shmflg, unsigned long *addr,
40 			    unsigned long shmlba)
41 {
42 	return -ENOSYS;
43 }
44 static inline int is_file_shm_hugepages(struct file *file)
45 {
46 	return 0;
47 }
48 static inline void exit_shm(struct task_struct *task)
49 {
50 }
51 #endif
52 
53 #endif /* _LINUX_SHM_H_ */
54