linux-kernel - Re: [PATCH] scsi: core: Switch to kvfree

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Message-ID: <YbpGq1GkO/14i939@pc638.lan>
Date:   Wed, 15 Dec 2021 20:48:59 +0100
From:   Uladzislau Rezki <urezki@...il.com>
To:     "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        linux-scsi@...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>
Subject: Re: [PATCH] scsi: core: Switch to kvfree_rcu() API

On Wed, Dec 15, 2021 at 12:18:45PM +0100, Uladzislau Rezki (Sony) wrote:
> 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: James E.J. Bottomley <jejb@...ux.ibm.com>
> TO: Martin K. Petersen <martin.petersen@...cle.com>
> TO: linux-scsi@...r.kernel.org
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
> ---
>  drivers/scsi/device_handler/scsi_dh_alua.c | 3 +--
>  drivers/scsi/device_handler/scsi_dh_rdac.c | 3 +--
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
> index 37d06f993b76..308246ce346a 100644
> --- a/drivers/scsi/device_handler/scsi_dh_alua.c
> +++ b/drivers/scsi/device_handler/scsi_dh_alua.c
> @@ -1238,8 +1238,7 @@ static void alua_bus_detach(struct scsi_device *sdev)
>  		kref_put(&pg->kref, release_port_group);
>  	}
>  	sdev->handler_data = NULL;
> -	synchronize_rcu();
> -	kfree(h);
> +	kvfree_rcu(h);
>  }
>  
>  static struct scsi_device_handler alua_dh = {
> diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
> index 66652ab409cc..dc687021ff3a 100644
> --- a/drivers/scsi/device_handler/scsi_dh_rdac.c
> +++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
> @@ -782,8 +782,7 @@ static void rdac_bus_detach( struct scsi_device *sdev )
>  	}
>  	spin_unlock(&list_lock);
>  	sdev->handler_data = NULL;
> -	synchronize_rcu();
> -	kfree(h);
> +	kvfree_rcu(h);
>  }
>  
>  static struct scsi_device_handler rdac_dh = {
> -- 
> 2.30.2
> 
+ James E.J. Bottomley <jejb@...ux.ibm.com>
+ Martin K. Petersen <martin.petersen@...cle.com>
+ linux-scsi@...r.kernel.org

--
Vlad Rezki