linux-kernel - Re: [PATCH 1/1] drivers: clk: sunxi: Fix memory leakage in clk-sunxi.c

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Date:	Mon, 14 Oct 2013 21:32:01 +0200
From:	Maxime Ripard <maxime.ripard@...e-electrons.com>
To:	"Victor N. Ramos Mello" <victornrm@...il.com>
Cc:	Mike Turquette <mturquette@...aro.org>,
	Emilio López <emilio@...pez.com.ar>,
	Gregory CLEMENT <gregory.clement@...e-electrons.com>,
	Stephen Boyd <sboyd@...eaurora.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] drivers: clk: sunxi: Fix memory leakage in
 clk-sunxi.c

Hi Victor,

On Sat, Oct 12, 2013 at 07:05:54PM -0300, Victor N. Ramos Mello wrote:
> From: "Victor N. Ramos Mello" <victornrm@...il.com>
> 
> Fix a possible memory leak in sun4i_osc_clk_setup().
> Moved clock-frequency check to save superfluous allocation.
> 
> Signed-off-by: Victor N. Ramos Mello <victornrm@...il.com>
> ---
>  drivers/clk/sunxi/clk-sunxi.c |   16 +++++++++-------
>  1 files changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
> index 34ee69f..a741770 100644
> --- a/drivers/clk/sunxi/clk-sunxi.c
> +++ b/drivers/clk/sunxi/clk-sunxi.c
> @@ -38,18 +38,16 @@ static void __init sun4i_osc_clk_setup(struct device_node *node)
>  	const char *clk_name = node->name;
>  	u32 rate;
>  
> +	if (of_property_read_u32(node, "clock-frequency", &rate))
> +		return;
> +
>  	/* allocate fixed-rate and gate clock structs */
>  	fixed = kzalloc(sizeof(struct clk_fixed_rate), GFP_KERNEL);
>  	if (!fixed)
>  		return;
>  	gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL);
> -	if (!gate) {
> -		kfree(fixed);
> -		return;
> -	}
> -
> -	if (of_property_read_u32(node, "clock-frequency", &rate))
> -		return;
> +	if (!gate)
> +		goto err_gate;
>  
>  	/* set up gate and fixed rate properties */
>  	gate->reg = of_iomap(node, 0);
> @@ -67,7 +65,11 @@ static void __init sun4i_osc_clk_setup(struct device_node *node)
>  	if (!IS_ERR(clk)) {
>  		of_clk_add_provider(node, of_clk_src_simple_get, clk);
>  		clk_register_clkdev(clk, clk_name, NULL);
> +		return;
>  	}
> +	kfree(gate);
> +err_gate:
> +	kfree(fixed);

While the patch is appreciated, I find the logic here a bit backward
compared to what's usually done.

I'd rather see here something like

if (IS_ERR(clk))
	goto err_gate;

of_clk_add_provider(...);
clk_register_clkdev(...);

return;

err_gate:
	kfree(gate);
err_fixed:
	kfree(fixed);

But maybe it's just me.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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