linux-kernel - [PATCH] fs: nfs: sysfs: Switch to kvfree

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Date:   Wed, 15 Dec 2021 12:18:40 +0100
From:   "Uladzislau Rezki (Sony)" <urezki@...il.com>
To:     LKML <linux-kernel@...r.kernel.org>, RCU <rcu@...r.kernel.org>,
        "Paul E . McKenney" <paulmck@...nel.org>
Cc:     Michal Hocko <mhocko@...e.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Daniel Axtens <dja@...ens.net>,
        Frederic Weisbecker <frederic@...nel.org>,
        Neeraj Upadhyay <neeraju@...eaurora.org>,
        Joel Fernandes <joel@...lfernandes.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Theodore Y . Ts'o" <tytso@....edu>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Uladzislau Rezki <urezki@...il.com>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...ymobile.com>,
        Uladzislau Rezki <uladzislau.rezki@...y.com>
Subject: [PATCH] fs: nfs: sysfs: Switch to kvfree_rcu() API

From: Uladzislau Rezki <uladzislau.rezki@...y.com>

Instead of invoking a synchronize_rcu() to free a pointer
after a grace period we can directly make use of new API
that does the same but in more efficient way.

TO: Trond Myklebust <trond.myklebust@...merspace.com>
TO: linux-nfs@...r.kernel.org
Signed-off-by: Uladzislau Rezki <uladzislau.rezki@...y.com>
---
 fs/nfs/sysfs.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/nfs/sysfs.c b/fs/nfs/sysfs.c
index 8cb70755e3c9..ff88d5d58e1e 100644
--- a/fs/nfs/sysfs.c
+++ b/fs/nfs/sysfs.c
@@ -113,10 +113,9 @@ static ssize_t nfs_netns_identifier_store(struct kobject *kobj,
 	if (!p)
 		return -ENOMEM;
 	old = rcu_dereference_protected(xchg(&c->identifier, (char __rcu *)p), 1);
-	if (old) {
-		synchronize_rcu();
-		kfree(old);
-	}
+	if (old)
+		kvfree_rcu(old);
+
 	return count;
 }
 
-- 
2.30.2