xref: /freebsd/sys/contrib/openzfs/include/os/linux/kernel/linux/mm_compat.h (revision 7a7741af18d6c8a804cc643cb7ecda9d730c6aa6)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or https://opensource.org/licenses/CDDL-1.0.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 2023, 2024, Klara Inc.
24  * Copyright (c) 2024, Rob Norris <robn@despairlabs.com>
25  */
26 
27 #ifndef _ZFS_MM_COMPAT_H
28 #define	_ZFS_MM_COMPAT_H
29 
30 #include <linux/mm.h>
31 #include <linux/pagemap.h>
32 
33 /* 5.4 introduced page_size(). Older kernels can use a trivial macro instead */
34 #ifndef HAVE_MM_PAGE_SIZE
35 #define	page_size(p) ((unsigned long)(PAGE_SIZE << compound_order(p)))
36 #endif
37 
38 /* 6.11 removed page_mapping(). A simple wrapper around folio_mapping() works */
39 #ifndef HAVE_MM_PAGE_MAPPING
40 #define	page_mapping(p) folio_mapping(page_folio(p))
41 #endif
42 
43 /*
44  * 6.12 removed PG_error, SetPageError and ClearPageError, with no direct
45  * replacement, because page writeback errors are recorded elsewhere. Since we
46  * only use the page cache to assist with mmap(), never directly backing it
47  * with IO, it shouldn't be possible for this condition to occur on our pages
48  * anyway, even if this is the right way to report it. So it should be safe
49  * to remove, but for avoidance of doubt, we make it a no-op on 6.12 and leave
50  * it for everything else.
51  */
52 #ifndef HAVE_MM_PAGE_FLAG_ERROR
53 #define	SetPageError(p)		do {} while (0)
54 #define	ClearPageError(p)	do {} while (0)
55 #endif
56 
57 #endif /* _ZFS_MM_COMPAT_H */
58