1 files changed, 26 insertions, 27 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 953e843..1af963e 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -565,50 +565,49 @@ void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
  *	Drop dentry for @sd.  @sd must have been unlinked from its
  *	parent on entry to this function such that it can't be looked
  *	up anymore.
- *
- *	@sd->s_dentry which is protected with sysfs_assoc_lock points
- *	to the currently associated dentry but we're not holding a
- *	reference to it and racing with dput().  Grab dcache_lock and
- *	verify dentry before dropping it.  If @sd->s_dentry is NULL or
- *	dput() beats us, no need to bother.
  */
 static void sysfs_drop_dentry(struct sysfs_dirent *sd)
 {
-	struct dentry *dentry = NULL;
 	struct inode *inode;
+	struct dentry *dentry;
+
+	inode = ilookup(sysfs_sb, sd->s_ino);
+	if (!inode)
+		return;
 
-	/* We're not holding a reference to ->s_dentry dentry but the
-	 * field will stay valid as long as sysfs_assoc_lock is held.
+	/* Drop any existing dentries associated with sd.
+	 *
+	 * For the dentry to be properly freed we need to grab a
+	 * reference to the dentry under the dcache lock,  unhash it,
+	 * and then put it.  The playing with the dentry count allows
+	 * dput to immediately free the dentry  if it is not in use.
 	 */
-	spin_lock(&sysfs_assoc_lock);
+repeat:
 	spin_lock(&dcache_lock);
-
-	/* drop dentry if it's there and dput() didn't kill it yet */
-	if (sd->s_dentry && sd->s_dentry->d_inode) {
-		dentry = dget_locked(sd->s_dentry);
+	list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
+		if (d_unhashed(dentry))
+			continue;
+		dget_locked(dentry);
 		spin_lock(&dentry->d_lock);
 		__d_drop(dentry);
 		spin_unlock(&dentry->d_lock);
+		spin_unlock(&dcache_lock);
+		dput(dentry);
+		goto repeat;
 	}
-
 	spin_unlock(&dcache_lock);
-	spin_unlock(&sysfs_assoc_lock);
-
-	dput(dentry);
 
 	/* adjust nlink and update timestamp */
-	inode = ilookup(sysfs_sb, sd->s_ino);
-	if (inode) {
-		mutex_lock(&inode->i_mutex);
+	mutex_lock(&inode->i_mutex);
 
-		inode->i_ctime = CURRENT_TIME;
+	inode->i_ctime = CURRENT_TIME;
+	drop_nlink(inode);
+	if (sysfs_type(sd) == SYSFS_DIR)
 		drop_nlink(inode);
-		if (sysfs_type(sd) == SYSFS_DIR)
-			drop_nlink(inode);
 
-		mutex_unlock(&inode->i_mutex);
-		iput(inode);
-	}
+	mutex_unlock(&inode->i_mutex);
+
+	iput(inode);
 }
 
 /**