linux-kernel - Re: [PATCH RESEND] ext4: Switch to kvfree

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Message-ID: <YbpE3uOu3ur/X5L4@pc638.lan>
Date:   Wed, 15 Dec 2021 20:41:18 +0100
From:   Uladzislau Rezki <urezki@...il.com>
To:     Theodore Ts'o <tytso@....edu>, linux-ext4@...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 RESEND] ext4: Switch to kvfree_rcu() API

On Wed, Dec 15, 2021 at 12:18:39PM +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: "Theodore Ts'o" <tytso@....edu>
> TO: linux-ext4@...r.kernel.org
> Signed-off-by: Uladzislau Rezki <uladzislau.rezki@...y.com>
> ---
>  fs/ext4/super.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 4e33b5eca694..111b0498a232 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -1886,8 +1886,7 @@ static int clear_qf_name(struct super_block *sb, int qtype)
>  		return -1;
>  	}
>  	rcu_assign_pointer(sbi->s_qf_names[qtype], NULL);
> -	synchronize_rcu();
> -	kfree(old_qname);
> +	kvfree_rcu(old_qname);
>  	return 1;
>  }
>  #endif
> -- 
> 2.30.2
> 
+ "Theodore Ts'o" <tytso@....edu>
+ linux-ext4@...r.kernel.org

--
Vlad Rezki