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         /*
  24          * The task created the shm object, for
  25          * task_lock(shp->shm_creator)
  26          */
  27         struct task_struct      *shm_creator;
  28
  29         /*
  30          * List by creator. task_lock(->shm_creator) required for read/write.
  31          * If list_empty(), then the creator is dead already.
  32          */
  33         struct list_head        shm_clist;
  34         struct ipc_namespace    *ns;
  35 } __randomize_layout;
  36
  37 /* shm_mode upper byte flags */
  38 #define SHM_DEST        01000   /* segment will be destroyed on last detach */
  39 #define SHM_LOCKED      02000   /* segment will not be swapped */
  40
  41 #ifdef CONFIG_SYSVIPC
  42 struct sysv_shm {
  43         struct list_head shm_clist;
  44 };
  45
  46 long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr,
  47               unsigned long shmlba);
  48 bool is_file_shm_hugepages(struct file *file);
  49 void exit_shm(struct task_struct *task);
  50 #define shm_init_task(task) INIT_LIST_HEAD(&(task)->sysvshm.shm_clist)
  51 #else
  52 struct sysv_shm {
  53         /* empty */
  54 };
  55
  56 static inline long do_shmat(int shmid, char __user *shmaddr,
  57                             int shmflg, unsigned long *addr,
  58                             unsigned long shmlba)
  59 {
  60         return -ENOSYS;
  61 }
  62 static inline bool is_file_shm_hugepages(struct file *file)
  63 {
  64         return false;
  65 }
  66 static inline void exit_shm(struct task_struct *task)
  67 {
  68 }
  69 static inline void shm_init_task(struct task_struct *task)
  70 {
  71 }
  72 #endif
  73
  74 #endif /* _LINUX_SHM_H_ */