diff options
| -rw-r--r-- | fs/sysfs/dir.c | 91 |
1 files changed, 16 insertions, 75 deletions
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 9fe83d23dc2c..1c3dc5d01ccd 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -78,9 +78,8 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd) * @sd: sysfs_dirent of interest * * Get dentry for @sd. Dentry is looked up if currently not - * present. This function climbs sysfs_dirent tree till it - * reaches a sysfs_dirent with valid dentry attached and descends - * down from there looking up dentry for each step. + * present. This function descends from the root looking up + * dentry for each step. * * LOCKING: * mutex_lock(sysfs_rename_mutex) @@ -90,86 +89,28 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd) */ struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd) { - struct sysfs_dirent *cur; - struct dentry *parent_dentry, *dentry; - int i, depth; + struct dentry *dentry = dget(sysfs_sb->s_root); - /* Find the first parent which has valid s_dentry and get the - * dentry. - */ - mutex_lock(&sysfs_mutex); - restart0: - spin_lock(&sysfs_assoc_lock); - restart1: - spin_lock(&dcache_lock); - - dentry = NULL; - depth = 0; - cur = sd; - while (!cur->s_dentry || !cur->s_dentry->d_inode) { - if (cur->s_flags & SYSFS_FLAG_REMOVED) { - dentry = ERR_PTR(-ENOENT); - depth = 0; - break; - } - cur = cur->s_parent; - depth++; - } - if (!IS_ERR(dentry)) - dentry = dget_locked(cur->s_dentry); + while (dentry->d_fsdata != sd) { + struct sysfs_dirent *cur; + struct dentry *parent; - spin_unlock(&dcache_lock); - spin_unlock(&sysfs_assoc_lock); - - /* from the found dentry, look up depth times */ - while (depth--) { - /* find and get depth'th ancestor */ - for (cur = sd, i = 0; cur && i < depth; i++) + /* find the first ancestor which hasn't been looked up */ + cur = sd; + while (cur->s_parent != dentry->d_fsdata) cur = cur->s_parent; - /* This can happen if tree structure was modified due - * to move/rename. Restart. - */ - if (i != depth) { - dput(dentry); - goto restart0; - } - - sysfs_get(cur); - - mutex_unlock(&sysfs_mutex); - /* look it up */ - parent_dentry = dentry; - mutex_lock(&parent_dentry->d_inode->i_mutex); - dentry = lookup_one_len_kern(cur->s_name, parent_dentry, + parent = dentry; + mutex_lock(&parent->d_inode->i_mutex); + dentry = lookup_one_len_kern(cur->s_name, parent, strlen(cur->s_name)); - mutex_unlock(&parent_dentry->d_inode->i_mutex); - dput(parent_dentry); - - if (IS_ERR(dentry)) { - sysfs_put(cur); - return dentry; - } + mutex_unlock(&parent->d_inode->i_mutex); + dput(parent); - mutex_lock(&sysfs_mutex); - spin_lock(&sysfs_assoc_lock); - - /* This, again, can happen if tree structure has - * changed and we looked up the wrong thing. Restart. - */ - if (cur->s_dentry != dentry) { - dput(dentry); - sysfs_put(cur); - goto restart1; - } - - spin_unlock(&sysfs_assoc_lock); - - sysfs_put(cur); + if (IS_ERR(dentry)) + break; } - - mutex_unlock(&sysfs_mutex); return dentry; } |