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authorTejun Heo <htejun@gmail.com>2007-06-14 03:45:15 +0900
committerGreg Kroah-Hartman <gregkh@suse.de>2007-07-11 16:09:04 -0700
commit2b29ac252afff87b8465b064ca2d9740cf1f6e52 (patch)
tree9f4930db68ace50adc7c11feba12aafe34e2cdbe /fs/sysfs/sysfs.h
parentaecdcedaab49ca40620dc7dd70f67ee7269a66c9 (diff)
downloadlinux-2b29ac252afff87b8465b064ca2d9740cf1f6e52.tar.bz2
sysfs: reimplement symlink using sysfs_dirent tree
sysfs symlink is implemented by referencing dentry and kobject from sysfs_dirent - symlink entry references kobject, dentry is used to walk the tree. This complicates object lifetimes rules and is dangerous - for example, there is no way to tell to which module the target of a symlink belongs and referencing that kobject can make it linger after the module is gone. This patch reimplements symlink using only sysfs_dirent tree. sd for a symlink points and holds reference to the target sysfs_dirent and all walking is done using sysfs_dirent tree. Simpler and safer. Please read the following message for more info. http://article.gmane.org/gmane.linux.kernel/510293 Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs/sysfs/sysfs.h')
-rw-r--r--fs/sysfs/sysfs.h9
1 files changed, 5 insertions, 4 deletions
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 718e2e123fae..60717660ac55 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -3,7 +3,7 @@ struct sysfs_elem_dir {
};
struct sysfs_elem_symlink {
- struct kobject * target_kobj;
+ struct sysfs_dirent * target_sd;
};
struct sysfs_elem_attr {
@@ -100,10 +100,11 @@ static inline struct kobject *sysfs_get_kobject(struct dentry *dentry)
spin_lock(&dcache_lock);
if (!d_unhashed(dentry)) {
struct sysfs_dirent * sd = dentry->d_fsdata;
+
if (sd->s_type & SYSFS_KOBJ_LINK)
- kobj = kobject_get(sd->s_elem.symlink.target_kobj);
- else
- kobj = kobject_get(sd->s_elem.dir.kobj);
+ sd = sd->s_elem.symlink.target_sd;
+
+ kobj = kobject_get(sd->s_elem.dir.kobj);
}
spin_unlock(&dcache_lock);