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- /* 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 {
- u64 i_seq;
- unsigned long pgoff;
- unsigned int offset;
- } shared;
- struct {
- union {
- struct mm_struct *mm;
- u64 __tmp;
- };
- unsigned long address;
- unsigned int offset;
- } private;
- struct {
- u64 ptr;
- unsigned long word;
- unsigned int offset;
- } both;
- };
- #define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = 0ULL } }
- #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
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