From: Nick Piggin <npiggin@kernel.dk>
Date: Fri, 7 Jan 2011 06:49:41 +0000 (+1100)
Subject: fs: dcache reduce locking in d_alloc
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=89ad485f01fd83c47f17a128db3bd7b89c0f244f;p=linux-beck.git

fs: dcache reduce locking in d_alloc

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
---

diff --git a/fs/dcache.c b/fs/dcache.c
index 98a05696593e..ccdc5c2512df 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1253,11 +1253,13 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
 
 	if (parent) {
 		spin_lock(&parent->d_lock);
-		spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
+		/*
+		 * don't need child lock because it is not subject
+		 * to concurrency here
+		 */
 		dentry->d_parent = dget_dlock(parent);
 		dentry->d_sb = parent->d_sb;
 		list_add(&dentry->d_u.d_child, &parent->d_subdirs);
-		spin_unlock(&dentry->d_lock);
 		spin_unlock(&parent->d_lock);
 	}