linux-kernel - Re: [PATCH] spi: Fix reference count leak in slave

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Message-ID: <Z9qgENjcGFF-rDJe@smile.fi.intel.com>
Date: Wed, 19 Mar 2025 12:44:32 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Miaoqian Lin <linmq006@...il.com>
Cc: Mark Brown <broonie@...nel.org>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] spi: Fix reference count leak in slave_show()

On Wed, Mar 19, 2025 at 11:23:04AM +0800, Miaoqian Lin wrote:
> Fix a reference count leak in slave_show() by properly putting the device
> reference obtained from device_find_any_child().

...

>  	struct device *child;
> +	int ret;
>  
>  	child = device_find_any_child(&ctlr->dev);
> -	return sysfs_emit(buf, "%s\n", child ? to_spi_device(child)->modalias : NULL);
> +	ret = sysfs_emit(buf, "%s\n", child ? to_spi_device(child)->modalias : NULL);
> +	put_device(child);
> +
> +	return ret;

Can be written better in case of NULL:

	child = device_find_any_child(&ctlr->dev);
	if (child)
		return sysfs_emit(buf, "%s\n", child ? to_spi_device(child)->modalias);

	put_device(child);
	return sysfs_emit(buf, "%s\n", NULL);

No variable needed.

-- 
With Best Regards,
Andy Shevchenko