LXR linux/include/linux/shm.h

   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
   9struct 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        struct list_head        shm_clist;      /* list by creator */
  25};
  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#define SHM_HUGETLB     04000   /* segment will use huge TLB pages */
  31#define SHM_NORESERVE   010000  /* don't check for reservations */
  32
  33/* Bits [26:31] are reserved */
  34
  35/*
  36 * When SHM_HUGETLB is set bits [26:31] encode the log2 of the huge page size.
  37 * This gives us 6 bits, which is enough until someone invents 128 bit address
  38 * spaces.
  39 *
  40 * Assume these are all power of twos.
  41 * When 0 use the default page size.
  42 */
  43#define SHM_HUGE_SHIFT  26
  44#define SHM_HUGE_MASK   0x3f
  45#define SHM_HUGE_2MB    (21 << SHM_HUGE_SHIFT)
  46#define SHM_HUGE_1GB    (30 << SHM_HUGE_SHIFT)
  47
  48#ifdef CONFIG_SYSVIPC
  49struct sysv_shm {
  50        struct list_head shm_clist;
  51};
  52
  53long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr,
  54              unsigned long shmlba);
  55bool is_file_shm_hugepages(struct file *file);
  56void exit_shm(struct task_struct *task);
  57#define shm_init_task(task) INIT_LIST_HEAD(&(task)->sysvshm.shm_clist)
  58#else
  59struct sysv_shm {
  60        /* empty */
  61};
  62
  63static inline long do_shmat(int shmid, char __user *shmaddr,
  64                            int shmflg, unsigned long *addr,
  65                            unsigned long shmlba)
  66{
  67        return -ENOSYS;
  68}
  69static inline bool is_file_shm_hugepages(struct file *file)
  70{
  71        return false;
  72}
  73static inline void exit_shm(struct task_struct *task)
  74{
  75}
  76static inline void shm_init_task(struct task_struct *task)
  77{
  78}
  79#endif
  80
  81#endif /* _LINUX_SHM_H_ */
  82