linux-kernel - RE: [PATCH 1/3] net: fec: Remove redundant checks for NULL clk pointer

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Date:	Tue, 1 Dec 2015 02:04:39 +0000
From:	Duan Andy <fugang.duan@...escale.com>
To:	Lothar Waßmann <LW@...O-electronics.de>,
	Andrew Lunn <andrew@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Fabio Estevam <Fabio.Estevam@...escale.com>,
	Greg Ungerer <gerg@...inux.org>,
	Kevin Hao <haokexin@...il.com>,
	Lucas Stach <l.stach@...gutronix.de>,
	Philippe Reynes <tremyfr@...il.com>,
	Richard Cochran <richardcochran@...il.com>,
	Russell King <rmk+kernel@....linux.org.uk>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	"Stefan Agner" <stefan@...er.ch>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
	"Uwe Kleine-K?nig" <u.kleine-koenig@...gutronix.de>
Subject: RE: [PATCH 1/3] net: fec: Remove redundant checks for NULL clk
 pointer

From: Lothar Waßmann <LW@...O-electronics.de> Sent: Monday, November 30, 2015 7:33 PM
> To: Andrew Lunn; David S. Miller; Estevam Fabio-R49496; Greg Ungerer;
> Kevin Hao; Lothar Waßmann; Lucas Stach; Duan Fugang-B38611; Philippe
> Reynes; Richard Cochran; Russell King; Sascha Hauer; Stefan Agner; linux-
> kernel@...r.kernel.org; netdev@...r.kernel.org; Jeff Kirsher; Uwe Kleine-
> König
> Subject: [PATCH 1/3] net: fec: Remove redundant checks for NULL clk
> pointer
> 
> NULL is a valid argument to clk_enable()/clk_disable(). Remove redundant
> checks before calling those functions.
> 
> Signed-off-by: Lothar Waßmann <LW@...O-electronics.de>
> ---
>  drivers/net/ethernet/freescale/fec_main.c | 23 +++++++++--------------
>  1 file changed, 9 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> b/drivers/net/ethernet/freescale/fec_main.c
> index d2328fc..e17d74f 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -1873,35 +1873,30 @@ static int fec_enet_clk_enable(struct net_device
> *ndev, bool enable)
>  			}
>  			mutex_unlock(&fep->ptp_clk_mutex);
>  		}
> -		if (fep->clk_ref) {
> -			ret = clk_prepare_enable(fep->clk_ref);
> -			if (ret)
> -				goto failed_clk_ref;
> -		}
> +
> +		ret = clk_prepare_enable(fep->clk_ref);
> +		if (ret)
> +			goto failed_clk_ref;

If you want to clean up the code, pls also remove "fep->clk_enet_out" check in this brace.


>  	} else {
>  		clk_disable_unprepare(fep->clk_ahb);
> -		if (fep->clk_enet_out)
> -			clk_disable_unprepare(fep->clk_enet_out);
> +		clk_disable_unprepare(fep->clk_enet_out);
>  		if (fep->clk_ptp) {
>  			mutex_lock(&fep->ptp_clk_mutex);
>  			clk_disable_unprepare(fep->clk_ptp);
>  			fep->ptp_clk_on = false;
>  			mutex_unlock(&fep->ptp_clk_mutex);
>  		}
> -		if (fep->clk_ref)
> -			clk_disable_unprepare(fep->clk_ref);
> +		clk_disable_unprepare(fep->clk_ref);
>  	}
> 
>  	return 0;
> 
>  failed_clk_ref:
> -	if (fep->clk_ref)
> -		clk_disable_unprepare(fep->clk_ref);
> +	clk_disable_unprepare(fep->clk_ref);
>  failed_clk_ptp:
> -	if (fep->clk_enet_out)
> -		clk_disable_unprepare(fep->clk_enet_out);
> +	clk_disable_unprepare(fep->clk_enet_out);
>  failed_clk_enet_out:
> -		clk_disable_unprepare(fep->clk_ahb);
> +	clk_disable_unprepare(fep->clk_ahb);
> 
>  	return ret;
>  }
> --
> 2.1.4