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

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Date:   Wed, 15 Dec 2021 20:42:27 +0100
From:   Uladzislau Rezki <urezki@...il.com>
To:     Trond Myklebust <trond.myklebust@...merspace.com>,
        linux-nfs@...r.kernel.org
Cc:     LKML <linux-kernel@...r.kernel.org>, RCU <rcu@...r.kernel.org>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        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>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...ymobile.com>,
        Uladzislau Rezki <uladzislau.rezki@...y.com>
Subject: Re: [PATCH] fs: nfs: sysfs: Switch to kvfree_rcu() API

On Wed, Dec 15, 2021 at 12:18:40PM +0100, Uladzislau Rezki (Sony) wrote:
> 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
> 
+ Trond Myklebust <trond.myklebust@...merspace.com>                                                                                                                                    
+ linux-nfs@...r.kernel.org  

--
Vlad Rezki