linux-kernel - Re: [PATCH v3 08/10] clk: clock-wizard: Make the output names unique

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Message-ID: <20191128074505.GC1781@kadam>
Date:   Thu, 28 Nov 2019 10:45:05 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     shubhrajyoti.datta@...il.com
Cc:     linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        devel@...verdev.osuosl.org, mark.rutland@....com,
        devicetree@...r.kernel.org, sboyd@...nel.org,
        gregkh@...uxfoundation.org, mturquette@...libre.com,
        Shubhrajyoti Datta <shubhrajyoti.datta@...inx.com>,
        robh+dt@...nel.org, soren.brinkmann@...inx.com
Subject: Re: [PATCH v3 08/10] clk: clock-wizard: Make the output names unique

On Thu, Nov 28, 2019 at 12:06:15PM +0530, shubhrajyoti.datta@...il.com wrote:
> From: Shubhrajyoti Datta <shubhrajyoti.datta@...inx.com>
> 
> Incase there are more than one instance of the clocking wizard.
> And if the output name given is the same then the probe fails.
> Fix the same by appending the device name to the output name to
> make it unique.
> 
> Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@...inx.com>
> ---
>  drivers/clk/clk-xlnx-clock-wizard.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/clk/clk-xlnx-clock-wizard.c b/drivers/clk/clk-xlnx-clock-wizard.c
> index 75ea745..9993543 100644
> --- a/drivers/clk/clk-xlnx-clock-wizard.c
> +++ b/drivers/clk/clk-xlnx-clock-wizard.c
> @@ -555,6 +555,9 @@ static int clk_wzrd_probe(struct platform_device *pdev)
>  		ret = -ENOMEM;
>  		goto err_disable_clk;
>  	}
> +	outputs = of_property_count_strings(np, "clock-output-names");
> +	if (outputs == 1)
> +		flags = CLK_SET_RATE_PARENT;
>  	clk_wzrd->clks_internal[wzrd_clk_mul] = clk_register_fixed_factor
>  			(&pdev->dev, clk_name,
>  			 __clk_get_name(clk_wzrd->clk_in1),
> @@ -566,9 +569,6 @@ static int clk_wzrd_probe(struct platform_device *pdev)
>  		goto err_disable_clk;
>  	}
>  
> -	outputs = of_property_count_strings(np, "clock-output-names");
> -	if (outputs == 1)
> -		flags = CLK_SET_RATE_PARENT;
>  	clk_name = kasprintf(GFP_KERNEL, "%s_mul_div", dev_name(&pdev->dev));
>  	if (!clk_name) {
>  		ret = -ENOMEM;
> @@ -591,6 +591,7 @@ static int clk_wzrd_probe(struct platform_device *pdev)
>  	/* register div per output */
>  	for (i = outputs - 1; i >= 0 ; i--) {
>  		const char *clkout_name;
> +		const char *clkout_name_wiz;
>  
>  		if (of_property_read_string_index(np, "clock-output-names", i,
>  						  &clkout_name)) {
> @@ -599,9 +600,11 @@ static int clk_wzrd_probe(struct platform_device *pdev)
>  			ret = -EINVAL;
>  			goto err_rm_int_clks;
>  		}
> +		clkout_name_wiz = kasprintf(GFP_KERNEL, "%s_%s",
> +					    dev_name(&pdev->dev), clkout_name);

If this kasprintf() crashes then clk_wzrd_register_divf() will fail.
But that was a headache to review.  Just add a check for NULL.  We need
a kfree() as well.

One alternative would be to just declare a buffer on the stack and use
snprintf().  We don't need to keep the name around after the call to
clk_wzrd_register_divf().

regards,
dan carpenter