This is a note to let you know that I've just added the patch titled
debugfs: improve DEFINE_DEBUGFS_ATTRIBUTE for !CONFIG_DEBUG_FS
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
debugfs-improve-define_debugfs_attribute-for-config_debug_fs.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7f847dd31736f1284538e54f46cf10e63929eb7f Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@xxxxxxxx>
Date: Thu, 20 Oct 2016 22:07:53 +0200
Subject: debugfs: improve DEFINE_DEBUGFS_ATTRIBUTE for !CONFIG_DEBUG_FS
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
From: Arnd Bergmann <arnd@xxxxxxxx>
commit 7f847dd31736f1284538e54f46cf10e63929eb7f upstream.
The slp_s0_residency_usec debugfs file currently uses
DEFINE_DEBUGFS_ATTRIBUTE(), but that macro cannot really be used to
define files outside of the debugfs code, as it has no reference to
the get/set functions if CONFIG_DEBUG_FS is not defined:
drivers/platform/x86/intel_pmc_core.c:80:12: error: ‘pmc_core_dev_state_get’ defined but not used [-Werror=unused-function]
This fixes the macro to always contain the reference, and instead rely
on the stubbed-out debugfs_create_file to not actually refer to
its arguments so the compiler can still drop the reference.
This works because the attribute definition is always 'static',
and the dead-code removal silently drops all static symbols
that are not used.
Fixes: c64688081490 ("debugfs: add support for self-protecting attribute file fops")
Fixes: df2294fb6428 ("intel_pmc_core: Convert to DEFINE_DEBUGFS_ATTRIBUTE")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
[nicstange@xxxxxxxxx: Add dummy implementations of debugfs_attr_read() and
debugfs_attr_write() in order to protect against possibly broken dead
code elimination and to improve readability.
Correct CONFIG_DEBUGFS_FS -> CONFIG_DEBUG_FS typo in changelog.]
Signed-off-by: Nicolai Stange <nicstange@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/debugfs.h | 44 +++++++++++++++++++++++++++-----------------
1 file changed, 27 insertions(+), 17 deletions(-)
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -62,6 +62,21 @@ static inline const struct file_operatio
return filp->f_path.dentry->d_fsdata;
}
+#define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt) \
+static int __fops ## _open(struct inode *inode, struct file *file) \
+{ \
+ __simple_attr_check_format(__fmt, 0ull); \
+ return simple_attr_open(inode, file, __get, __set, __fmt); \
+} \
+static const struct file_operations __fops = { \
+ .owner = THIS_MODULE, \
+ .open = __fops ## _open, \
+ .release = simple_attr_release, \
+ .read = debugfs_attr_read, \
+ .write = debugfs_attr_write, \
+ .llseek = generic_file_llseek, \
+}
+
#if defined(CONFIG_DEBUG_FS)
struct dentry *debugfs_create_file(const char *name, umode_t mode,
@@ -99,21 +114,6 @@ ssize_t debugfs_attr_read(struct file *f
ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
size_t len, loff_t *ppos);
-#define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt) \
-static int __fops ## _open(struct inode *inode, struct file *file) \
-{ \
- __simple_attr_check_format(__fmt, 0ull); \
- return simple_attr_open(inode, file, __get, __set, __fmt); \
-} \
-static const struct file_operations __fops = { \
- .owner = THIS_MODULE, \
- .open = __fops ## _open, \
- .release = simple_attr_release, \
- .read = debugfs_attr_read, \
- .write = debugfs_attr_write, \
- .llseek = generic_file_llseek, \
-}
-
struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
struct dentry *new_dir, const char *new_name);
@@ -233,8 +233,18 @@ static inline void debugfs_use_file_fini
__releases(&debugfs_srcu)
{ }
-#define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt) \
- static const struct file_operations __fops = { 0 }
+static inline ssize_t debugfs_attr_read(struct file *file, char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ return -ENODEV;
+}
+
+static inline ssize_t debugfs_attr_write(struct file *file,
+ const char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ return -ENODEV;
+}
static inline struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
struct dentry *new_dir, char *new_name)
Patches currently in stable-queue which might be from arnd@xxxxxxxx are
queue-4.9/debugfs-improve-define_debugfs_attribute-for-config_debug_fs.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html