1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
From df2e89879bcaf45123233bc2d95acdfb6a4a5ee8 Mon Sep 17 00:00:00 2001
From: Cheyenne Wills <cwills@sinenomine.net>
Date: Fri, 8 Nov 2024 21:32:46 -0700
Subject: [PATCH 1/3] Linux: Define Clear/Set PageError macros as NOPs
The Linux 6.12 commit 'mm: remove PG_error' (09022bc196d23) removed
the PG_error page flag and the associated ClearPageError() and
SetPageError() functions (via removing the PAGEFLAG(Error, ...) macro).
The PG_error flag has not been used by core VFS/MM Linux code for some
time, possibly ever, and so our calls to these functions do not have any
practical effect, since we also do not check for the PG_error flag.
While we could simply remove these calls, play it safe and keep them
around until ClearPageError()/SetPageError() are removed.
The specific semantics of the PG_error flag are not completely well
defined in the Linux kernel, which appears to be one of the motivations
for its removal. Some Linux commits that mention some details on how the
flag is not useful for read errors include:
7edf1ec5b249 ceph: don't SetPageError on readpage errors
41a638a1b3fc affs: convert affs_symlink_read_folio() to use the folio
2b2553f12355 btrfs: stop setting PageError in the data I/O path
Add a configure test to see if ClearPageError()/SetPageError() are
available in the Linux kernel; if they are not, define
ClearPageError()/SetPageError() as no-ops.
Reviewed-on: https://gerrit.openafs.org/15876
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Tested-by: Cheyenne Wills <cwills@sinenomine.net>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Marcio Brito Barbosa <mbarbosa@sinenomine.net>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
(cherry picked from commit ec146905313aaef5998b7bdfe44e86ce541a73cf)
Change-Id: I2c65a2a9efe380cd2ba211ae033392fc0597b898
---
src/afs/LINUX/osi_compat.h | 13 +++++++++++++
src/afs/LINUX/osi_pagecopy.c | 4 ++++
src/cf/linux-kernel-func.m4 | 16 ++++++++++++++++
3 files changed, 33 insertions(+)
diff --git a/src/afs/LINUX/osi_compat.h b/src/afs/LINUX/osi_compat.h
index 44bcb440e..e8b8f100e 100644
--- a/src/afs/LINUX/osi_compat.h
+++ b/src/afs/LINUX/osi_compat.h
@@ -31,6 +31,19 @@
# endif
#endif
+#if defined(HAVE_LINUX_NO_SETPAGEERROR)
+static inline void
+ClearPageError(struct page *p)
+{
+ return;
+}
+static inline void
+SetPageError(struct page *p)
+{
+ return;
+}
+#endif
+
#if !defined(HAVE_LINUX_KTHREAD_COMPLETE_AND_EXIT)
# define kthread_complete_and_exit complete_and_exit
#endif
diff --git a/src/afs/LINUX/osi_pagecopy.c b/src/afs/LINUX/osi_pagecopy.c
index 42f5e38e0..061d8c640 100644
--- a/src/afs/LINUX/osi_pagecopy.c
+++ b/src/afs/LINUX/osi_pagecopy.c
@@ -56,12 +56,16 @@
#include <afsconfig.h>
#include "afs/param.h"
+#include "afs/sysincludes.h"
+#include "afsincludes.h"
+
#include <linux/pagemap.h>
#include <linux/kthread.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#include "osi_pagecopy.h"
+#include "osi_compat.h"
static DECLARE_WAIT_QUEUE_HEAD (afs_pagecopy_wq);
static spinlock_t afs_pagecopy_lock;
diff --git a/src/cf/linux-kernel-func.m4 b/src/cf/linux-kernel-func.m4
index 69b79c5cf..71a0c2c39 100644
--- a/src/cf/linux-kernel-func.m4
+++ b/src/cf/linux-kernel-func.m4
@@ -300,6 +300,22 @@ AC_CHECK_LINUX_FUNC([no_generic_file_splice_read],
[[static char buff[10], *ap;
ap = generic_file_splice_read(buff); ]])
+dnl Linux 6.12 removed the PG_error flag from the page flags along with the
+dnl associated functions ClearPageError() and SetPageError(). Check to see if
+dnl these functions are present in the kernel.
+dnl
+dnl To check if ClearPageError() and SetPageError() are missing, define our own
+dnl functions with the same name but with a conflicting signature. If we can
+dnl define them, the real functions must be missing.
+AC_CHECK_LINUX_FUNC([no_setpageerror],
+ [[#include <asm/page.h>
+ #include <linux/page-flags.h>
+ static inline char ClearPageError(char c) { return c;}
+ static inline char SetPageError(char c) { return c;}]],
+ [[static char r;
+ r = ClearPageError('x');
+ r = SetPageError('x');]])
+
dnl Consequences - things which get set as a result of the
dnl above tests
AS_IF([test "x$ac_cv_linux_func_d_alloc_anon" = "xno"],
--
2.47.0
|