netdev - Re: [PATCH 7/9] net: macb: avoid uninitialized variables

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Date:	Wed, 27 Jan 2016 16:51:36 +0100
From:	Nicolas Ferre <nicolas.ferre@...el.com>
To:	Arnd Bergmann <arnd@...db.de>,
	"David S. Miller" <davem@...emloft.net>
CC:	<linux-arm-kernel@...ts.infradead.org>, <netdev@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 7/9] net: macb: avoid uninitialized variables

Le 27/01/2016 15:04, Arnd Bergmann a écrit :
> The macb_clk_init function returns three clock pointers, unless
> the it fails to get the first ones. We correctly handle the
> failure case by propagating the error from macb_probe, but
> gcc does not realize this and incorrectly warns about a later
> use of those:
> 
> In file included from /git/arm-soc/drivers/net/ethernet/cadence/macb.c:12:0:
> drivers/net/ethernet/cadence/macb.c: In function 'macb_probe':
> include/linux/clk.h:484:2: error: 'tx_clk' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>   clk_disable(clk);
>   ^
> drivers/net/ethernet/cadence/macb.c:2822:28: note: 'tx_clk' was declared here
>   struct clk *pclk, *hclk, *tx_clk;
>                             ^
> In file included from /git/arm-soc/drivers/net/ethernet/cadence/macb.c:12:0:
> include/linux/clk.h:484:2: error: 'hclk' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>   clk_disable(clk);
>   ^
> drivers/net/ethernet/cadence/macb.c:2822:21: note: 'hclk' was declared here
>   struct clk *pclk, *hclk, *tx_clk;
>                      ^
> 
> This shuts up the misleading warnings by ensuring that the
> macb_clk_init() always stores something into all three pointers.
> 
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

Okay Arnd, thanks!

Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>

> ---
>  drivers/net/ethernet/cadence/macb.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
> index 9d9984a87d42..d3aa74f9db79 100644
> --- a/drivers/net/ethernet/cadence/macb.c
> +++ b/drivers/net/ethernet/cadence/macb.c
> @@ -2268,6 +2268,7 @@ static int macb_clk_init(struct platform_device *pdev, struct clk **pclk,
>  {
>  	int err;
>  
> +	*tx_clk = *hclk = NULL;
>  	*pclk = devm_clk_get(&pdev->dev, "pclk");
>  	if (IS_ERR(*pclk)) {
>  		err = PTR_ERR(*pclk);
> 


-- 
Nicolas Ferre