linux-kernel - Re: [PATCH] can: Delete unnecessary checks before the macro call “dev_kfree

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Message-ID: <dc19a08f-eba9-ebd3-ef0a-3f99e06c9916@geanix.com>
Date:   Thu, 22 Aug 2019 11:13:41 +0200
From:   Sean Nyekjaer <sean@...nix.com>
To:     Markus Elfring <Markus.Elfring@....de>, linux-can@...r.kernel.org,
        netdev@...r.kernel.org, Allison Randal <allison@...utok.net>,
        "David S. Miller" <davem@...emloft.net>,
        Enrico Weigelt <lkml@...ux.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Gustavo A. R. Silva" <gustavo@...eddedor.com>,
        Lukas Wunner <lukas@...ner.de>,
        Marc Kleine-Budde <mkl@...gutronix.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Weitao Hou <houweitaoo@...il.com>,
        Wolfgang Grandegger <wg@...ndegger.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] can: Delete unnecessary checks before the macro call “dev_kfree_skb”



On 21/08/2019 21.30, Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Wed, 21 Aug 2019 21:16:15 +0200
> 
> The dev_kfree_skb() function performs also input parameter validation.
> Thus the test around the shown calls is not needed.
> 
> This issue was detected by using the Coccinelle software.
> 
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
Acked-by: Sean Nyekjaer <sean@...nix.com>
> ---
>   drivers/net/can/spi/hi311x.c  | 3 +--
>   drivers/net/can/spi/mcp251x.c | 3 +--
>   2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/can/spi/hi311x.c b/drivers/net/can/spi/hi311x.c
> index 03a711c3221b..7c7c7e78214c 100644
> --- a/drivers/net/can/spi/hi311x.c
> +++ b/drivers/net/can/spi/hi311x.c
> @@ -184,8 +184,7 @@ static void hi3110_clean(struct net_device *net)
> 
>   	if (priv->tx_skb || priv->tx_len)
>   		net->stats.tx_errors++;
> -	if (priv->tx_skb)
> -		dev_kfree_skb(priv->tx_skb);
> +	dev_kfree_skb(priv->tx_skb);
>   	if (priv->tx_len)
>   		can_free_echo_skb(priv->net, 0);
>   	priv->tx_skb = NULL;
> diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
> index 12358f06d194..1c496d2adb45 100644
> --- a/drivers/net/can/spi/mcp251x.c
> +++ b/drivers/net/can/spi/mcp251x.c
> @@ -274,8 +274,7 @@ static void mcp251x_clean(struct net_device *net)
> 
>   	if (priv->tx_skb || priv->tx_len)
>   		net->stats.tx_errors++;
> -	if (priv->tx_skb)
> -		dev_kfree_skb(priv->tx_skb);
> +	dev_kfree_skb(priv->tx_skb);
>   	if (priv->tx_len)
>   		can_free_echo_skb(priv->net, 0);
>   	priv->tx_skb = NULL;
> --
> 2.23.0
> 

Good catch Markus :-)

/Sean