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authorEric W. Biederman <ebiederm@xmission.com>2010-02-11 15:21:53 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2010-03-07 17:04:51 -0800
commit6992f5334995af474c2b58d010d08bc597f0f2fe (patch)
treebef650bfb9355b8d7cbb7a5acb3632c02ec7fbe7 /include/linux
parenta2db6842873c8e5a70652f278d469128cb52db70 (diff)
sysfs: Use one lockdep class per sysfs attribute.
Acknowledge that the logical sysfs rwsem has one instance per sysfs attribute with different locking depencencies for different attributes. There is a sysfs idiom where writing to one sysfs file causes the addition or removal of other sysfs files. Lumping all of the sysfs attributes together in one lock class causes lockdep to generate lots of false positives. This introduces the requirement that non-static sysfs attributes need to be initialized with sysfs_attr_init or sysfs_bin_attr_init. Strictly speaking this requirement only exists when lockdep is enabled, and when lockdep is enabled we get a bit fat warning if this requirement is not met. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: WANG Cong <xiyou.wangcong@gmail.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/sysfs.h18
1 files changed, 18 insertions, 0 deletions
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 3e852658214..006c359e63c 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -15,6 +15,7 @@
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/list.h>
+#include <linux/lockdep.h>
#include <asm/atomic.h>
struct kobject;
@@ -29,8 +30,23 @@ struct attribute {
const char *name;
struct module *owner;
mode_t mode;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct lock_class_key *key;
+ struct lock_class_key skey;
+#endif
};
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#define sysfs_attr_init(attr) \
+do { \
+ static struct lock_class_key __key; \
+ \
+ (attr)->key = &__key; \
+} while(0)
+#else
+#define sysfs_attr_init(attr) do {} while(0)
+#endif
+
struct attribute_group {
const char *name;
mode_t (*is_visible)(struct kobject *,
@@ -74,6 +90,8 @@ struct bin_attribute {
struct vm_area_struct *vma);
};
+#define sysfs_bin_attr_init(bin_attr) sysfs_attr_init(&bin_attr->attr)
+
struct sysfs_ops {
ssize_t (*show)(struct kobject *, struct attribute *,char *);
ssize_t (*store)(struct kobject *,struct attribute *,const char *, size_t);