1/* SPDX-License-Identifier: MIT */
2/*
3 * Copyright © 2024 Intel Corporation
4 */
5
6#ifndef _TTM_BACKUP_H_
7#define _TTM_BACKUP_H_
8
9#include <linux/mm_types.h>
10#include <linux/shmem_fs.h>
11
12/**
13 * ttm_backup_handle_to_page_ptr() - Convert handle to struct page pointer
14 * @handle: The handle to convert.
15 *
16 * Converts an opaque handle received from the
17 * ttm_backup_backup_page() function to an (invalid)
18 * struct page pointer suitable for a struct page array.
19 *
20 * Return: An (invalid) struct page pointer.
21 */
22static inline struct page *
23ttm_backup_handle_to_page_ptr(unsigned long handle)
24{
25 return (struct page *)(handle << 1 | 1);
26}
27
28/**
29 * ttm_backup_page_ptr_is_handle() - Whether a struct page pointer is a handle
30 * @page: The struct page pointer to check.
31 *
32 * Return: true if the struct page pointer is a handld returned from
33 * ttm_backup_handle_to_page_ptr(). False otherwise.
34 */
35static inline bool ttm_backup_page_ptr_is_handle(const struct page *page)
36{
37 return (unsigned long)page & 1;
38}
39
40/**
41 * ttm_backup_page_ptr_to_handle() - Convert a struct page pointer to a handle
42 * @page: The struct page pointer to convert
43 *
44 * Return: The handle that was previously used in
45 * ttm_backup_handle_to_page_ptr() to obtain a struct page pointer, suitable
46 * for use as argument in the struct ttm_backup_drop() or
47 * ttm_backup_copy_page() functions.
48 */
49static inline unsigned long
50ttm_backup_page_ptr_to_handle(const struct page *page)
51{
52 WARN_ON(!ttm_backup_page_ptr_is_handle(page));
53 return (unsigned long)page >> 1;
54}
55
56void ttm_backup_drop(struct file *backup, pgoff_t handle);
57
58int ttm_backup_copy_page(struct file *backup, struct page *dst,
59 pgoff_t handle, bool intr);
60
61s64
62ttm_backup_backup_page(struct file *backup, struct page *page,
63 bool writeback, pgoff_t idx, gfp_t page_gfp,
64 gfp_t alloc_gfp);
65
66void ttm_backup_fini(struct file *backup);
67
68u64 ttm_backup_bytes_avail(void);
69
70struct file *ttm_backup_shmem_create(loff_t size);
71
72#endif
73