From: Al Viro <viro@zeniv.linux.org.uk>
Date: Tue, 21 Apr 2026 19:52:13 +0000 (-0400)
Subject: d_walk(): shrink rcu_read_lock() scope
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3ef89feb387f2da13df290ce3e38fe8284160a86;p=thirdparty%2Flinux.git

d_walk(): shrink rcu_read_lock() scope

we only need it to bridge over from ->d_lock scope of child to ->d_lock
scope of parent; dropping ->d_lock at rename_retry doesn't need to be
in rcu_read_lock() scope.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/dcache.c b/fs/dcache.c
index cf4bd6c37d04..94749442fa68 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1491,14 +1491,15 @@ resume:
 	/*
 	 * All done at this level ... ascend and resume the search.
 	 */
-	rcu_read_lock();
 ascend:
 	if (this_parent != parent) {
 		dentry = this_parent;
 		this_parent = dentry->d_parent;
 
+		rcu_read_lock();
 		spin_unlock(&dentry->d_lock);
 		spin_lock(&this_parent->d_lock);
+		rcu_read_unlock();
 
 		/* might go back up the wrong parent if we have had a rename. */
 		if (need_seqretry(&rename_lock, seq))
@@ -1506,7 +1507,6 @@ ascend:
 		/* go into the first sibling still alive */
 		hlist_for_each_entry_continue(dentry, d_sib) {
 			if (likely(!(dentry->d_flags & DCACHE_DENTRY_KILLED))) {
-				rcu_read_unlock();
 				goto resume;
 			}
 		}
@@ -1514,7 +1514,6 @@ ascend:
 	}
 	if (need_seqretry(&rename_lock, seq))
 		goto rename_retry;
-	rcu_read_unlock();
 
 out_unlock:
 	spin_unlock(&this_parent->d_lock);
@@ -1523,7 +1522,6 @@ out_unlock:
 
 rename_retry:
 	spin_unlock(&this_parent->d_lock);
-	rcu_read_unlock();
 	BUG_ON(seq & 1);
 	if (!retry)
 		return;