linux-kernel - [PATCH v3 16/21] fold dentry

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Message-Id: <20231124060422.576198-16-viro@zeniv.linux.org.uk>
Date:   Fri, 24 Nov 2023 06:04:17 +0000
From:   Al Viro <viro@...iv.linux.org.uk>
To:     linux-fsdevel@...r.kernel.org
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Christian Brauner <brauner@...nel.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v3 16/21] fold dentry_kill() into dput()

Reviewed-by: Christian Brauner <brauner@...nel.org>
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/dcache.c | 37 ++++++++++++-------------------------
 1 file changed, 12 insertions(+), 25 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index a7f99d46c41b..5284b02747cd 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -756,28 +756,6 @@ void d_mark_dontcache(struct inode *inode)
 }
 EXPORT_SYMBOL(d_mark_dontcache);
 
-/*
- * Finish off a dentry we've decided to kill.
- * dentry->d_lock must be held, returns with it unlocked.
- * Returns dentry requiring refcount drop, or NULL if we're done.
- */
-static struct dentry *dentry_kill(struct dentry *dentry)
-	__releases(dentry->d_lock)
-{
-
-	dentry->d_lockref.count--;
-	rcu_read_lock();
-	if (likely(lock_for_kill(dentry))) {
-		struct dentry *parent = dentry->d_parent;
-		rcu_read_unlock();
-		__dentry_kill(dentry);
-		return parent != dentry ? parent : NULL;
-	}
-	rcu_read_unlock();
-	spin_unlock(&dentry->d_lock);
-	return NULL;
-}
-
 /*
  * Try to do a lockless dput(), and return whether that was successful.
  *
@@ -915,9 +893,18 @@ void dput(struct dentry *dentry)
 		}
 
 		/* Slow case: now with the dentry lock held */
-		rcu_read_unlock();
-		dentry->d_lockref.count = 1;
-		dentry = dentry_kill(dentry);
+		if (likely(lock_for_kill(dentry))) {
+			struct dentry *parent = dentry->d_parent;
+			rcu_read_unlock();
+			__dentry_kill(dentry);
+			if (dentry == parent)
+				return;
+			dentry = parent;
+		} else {
+			rcu_read_unlock();
+			spin_unlock(&dentry->d_lock);
+			return;
+		}
 	}
 }
 EXPORT_SYMBOL(dput);
-- 
2.39.2