sysfs: Remove s_dentry

The only uses of s_dentry left are the code that maintains
s_dentry and trivial users that don't actually need it.
So this patch removes the s_dentry maintenance code and
restructures the trivial uses to use something else.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 4 insertions, 30 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 1c3dc5d01ccd..36b6c796d4d5 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -289,22 +289,7 @@ static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
 {
         struct sysfs_dirent * sd = dentry->d_fsdata;
 
-        if (sd) {
-                /* sd->s_dentry is protected with sysfs_assoc_lock.
-                 * This allows sysfs_drop_dentry() to dereference it.
-                 */
-                spin_lock(&sysfs_assoc_lock);
-
-                /* The dentry might have been deleted or another
-                 * lookup could have happened updating sd->s_dentry to
-                 * point the new dentry.  Ignore if it isn't pointing
-                 * to this dentry.
-                 */
-                if (sd->s_dentry == dentry)
-                        sd->s_dentry = NULL;
-                spin_unlock(&sysfs_assoc_lock);
-                sysfs_put(sd);
-        }
+        sysfs_put(sd);
         iput(inode);
 }
 
@@ -352,9 +337,6 @@ struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
  *      @sd: target sysfs_dirent
  *      @dentry: dentry to associate
  *
- *      Associate @sd with @dentry.  This is protected by
- *      sysfs_assoc_lock to avoid race with sysfs_d_iput().
- *
  *      LOCKING:
  *      mutex_lock(sysfs_mutex)
  */
@@ -362,12 +344,6 @@ static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry)
 {
         dentry->d_op = &sysfs_dentry_ops;
         dentry->d_fsdata = sysfs_get(sd);
-
-        /* protect sd->s_dentry against sysfs_d_iput */
-        spin_lock(&sysfs_assoc_lock);
-        sd->s_dentry = dentry;
-        spin_unlock(&sysfs_assoc_lock);
-
         d_rehash(dentry);
 }
 
@@ -846,7 +822,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 
         /* rename */
         d_add(new_dentry, NULL);
-        d_move(sd->s_dentry, new_dentry);
+        d_move(old_dentry, new_dentry);
 
         error = 0;
         goto out_unlock;
@@ -881,7 +857,7 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
                 error = PTR_ERR(old_dentry);
                 goto out_dput;
         }
-        old_parent = sd->s_parent->s_dentry;
+        old_parent = old_dentry->d_parent;
 
         new_parent = sysfs_get_dentry(new_parent_sd);
         if (IS_ERR(new_parent)) {
@@ -907,7 +883,7 @@ again:
         } else
                 error = 0;
         d_add(new_dentry, NULL);
-        d_move(sd->s_dentry, new_dentry);
+        d_move(old_dentry, new_dentry);
         dput(new_dentry);
 
         /* Remove from old parent's list and insert into new parent's list. */
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 8989cbb51a39..28bf359981fc 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -56,7 +56,6 @@ static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
                 iput(inode);
                 return -ENOMEM;
         }
-        sysfs_root.s_dentry = root;
         root->d_fsdata = &sysfs_root;
         sb->s_root = root;
         return 0;
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 179e6a26ece1..791b3ed91a9b 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -37,7 +37,6 @@ struct sysfs_dirent {
         unsigned int            s_flags;
         umode_t                 s_mode;
         ino_t                   s_ino;
-        struct dentry           * s_dentry;
         struct iattr            * s_iattr;
         atomic_t                s_event;
 };