/* SPDX-License-Identifier: GPL-2.0 */

  #ifndef _LINUX_FUTEX_H
  #define _LINUX_FUTEX_H

  #include <linux/sched.h>

  #include <linux/ktime.h>

  #include <uapi/linux/futex.h>

  struct inode;
  struct mm_struct;
  struct task_struct;

  /*
   * Futexes are matched on equal values of this key.
   * The key type depends on whether it's a shared or private mapping.
   * Don't rearrange members without looking at hash_futex().
   *
   * offset is aligned to a multiple of sizeof(u32) (== 4) by definition.

   * We use the two low order bits of offset to tell what is the kind of key :
   *  00 : Private process futex (PTHREAD_PROCESS_PRIVATE)
   *       (no reference on an inode or mm)
   *  01 : Shared futex (PTHREAD_PROCESS_SHARED)
   *	mapped on a file (reference on the underlying inode)
   *  10 : Shared futex (PTHREAD_PROCESS_SHARED)
   *       (but private mapping on an mm, and reference taken on it)
  */
  
  #define FUT_OFF_INODE    1 /* We set bit 0 if key has a reference on inode */
  #define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */

  union futex_key {
  	struct {
  		unsigned long pgoff;
  		struct inode *inode;
  		int offset;
  	} shared;
  	struct {
  		unsigned long address;
  		struct mm_struct *mm;
  		int offset;
  	} private;
  	struct {
  		unsigned long word;
  		void *ptr;
  		int offset;
  	} both;
  };

  #define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = NULL } }

  #ifdef CONFIG_FUTEX

  enum {
  	FUTEX_STATE_OK,

  	FUTEX_STATE_EXITING,

  	FUTEX_STATE_DEAD,
  };

  static inline void futex_init_task(struct task_struct *tsk)

  {

  	tsk->robust_list = NULL;
  #ifdef CONFIG_COMPAT
  	tsk->compat_robust_list = NULL;
  #endif
  	INIT_LIST_HEAD(&tsk->pi_state_list);
  	tsk->pi_state_cache = NULL;

  	tsk->futex_state = FUTEX_STATE_OK;

  	mutex_init(&tsk->futex_exit_mutex);

  }

  void futex_exit_recursive(struct task_struct *tsk);

  void futex_exit_release(struct task_struct *tsk);
  void futex_exec_release(struct task_struct *tsk);

  
  long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
  	      u32 __user *uaddr2, u32 val2, u32 val3);
  #else
  static inline void futex_init_task(struct task_struct *tsk) { }

  static inline void futex_exit_recursive(struct task_struct *tsk) { }

  static inline void futex_exit_release(struct task_struct *tsk) { }
  static inline void futex_exec_release(struct task_struct *tsk) { }

  static inline long do_futex(u32 __user *uaddr, int op, u32 val,
  			    ktime_t *timeout, u32 __user *uaddr2,
  			    u32 val2, u32 val3)
  {
  	return -EINVAL;
  }

  #endif

  #endif