fs: use hlist_unhashed

Use hlist_unhashed() instead of opencoded equivalent.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/dcache.c b/fs/dcache.c
index d9ca1e5..1c323dd 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -89,7 +89,7 @@
 	if (dentry->d_op && dentry->d_op->d_release)
 		dentry->d_op->d_release(dentry);
 	/* if dentry was never inserted into hash, immediate free is OK */
-	if (dentry->d_hash.pprev == NULL)
+	if (hlist_unhashed(&dentry->d_hash))
 		__d_free(dentry);
 	else
 		call_rcu(&dentry->d_u.d_rcu, d_callback);