include/linux/shm.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_SHM_H_
   3 #define _LINUX_SHM_H_
   4
   5 #include <linux/list.h>
   6 #include <asm/page.h>
   7 #include <uapi/linux/shm.h>
   8 #include <asm/shmparam.h>
   9
  10 struct shmid_kernel /* private to the kernel */
  11 {
  12         struct kern_ipc_perm    shm_perm;
  13         struct file             *shm_file;
  14         unsigned long           shm_nattch;
  15         unsigned long           shm_segsz;
  16         time64_t                shm_atim;
  17         time64_t                shm_dtim;
  18         time64_t                shm_ctim;
  19         pid_t                   shm_cprid;
  20         pid_t                   shm_lprid;
  21         struct user_struct      *mlock_user;
  22
  23         /* The task created the shm object.  NULL if the task is dead. */
  24         struct task_struct      *shm_creator;
  25         struct list_head        shm_clist;      /* list by creator */
  26 } __randomize_layout;
  27
  28 /* shm_mode upper byte flags */
  29 #define SHM_DEST        01000   /* segment will be destroyed on last detach */
  30 #define SHM_LOCKED      02000   /* segment will not be swapped */
  31
  32 #ifdef CONFIG_SYSVIPC
  33 struct sysv_shm {
  34         struct list_head shm_clist;
  35 };
  36
  37 long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr,
  38               unsigned long shmlba);
  39 bool is_file_shm_hugepages(struct file *file);
  40 void exit_shm(struct task_struct *task);
  41 #define shm_init_task(task) INIT_LIST_HEAD(&(task)->sysvshm.shm_clist)
  42 #else
  43 struct sysv_shm {
  44         /* empty */
  45 };
  46
  47 static inline long do_shmat(int shmid, char __user *shmaddr,
  48                             int shmflg, unsigned long *addr,
  49                             unsigned long shmlba)
  50 {
  51         return -ENOSYS;
  52 }
  53 static inline bool is_file_shm_hugepages(struct file *file)
  54 {
  55         return false;
  56 }
  57 static inline void exit_shm(struct task_struct *task)
  58 {
  59 }
  60 static inline void shm_init_task(struct task_struct *task)
  61 {
  62 }
  63 #endif
  64
  65 #endif /* _LINUX_SHM_H_ */