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Date:   Mon, 28 Feb 2022 14:03:26 -0600
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Stuart Yoder <stuyoder@gmail.com>,
        Laurentiu Tudor <laurentiu.tudor@nxp.com>,
        Abel Vesa <abel.vesa@nxp.com>, Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
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Subject: Re: [PATCH v3 01/11] driver: platform: Add helper for safer setting
 of driver_override
Message-ID: <20220228200326.GA516164@bhelgaas>
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In-Reply-To: <20220227135214.145599-2-krzysztof.kozlowski@canonical.com>
Precedence: bulk

On Sun, Feb 27, 2022 at 02:52:04PM +0100, Krzysztof Kozlowski wrote:
> Several core drivers and buses expect that driver_override is a
> dynamically allocated memory thus later they can kfree() it.

> +int driver_set_override(struct device *dev, const char **override,
> +			const char *s, size_t len)
> +{
> +	const char *new, *old;
> +	char *cp;
> +
> +	if (!dev || !override || !s)
> +		return -EINVAL;
> +
> +	/* We need to keep extra room for a newline */

It would help a lot to extend this comment with a hint about where the
room for a newline is needed.  It was confusing even before, but it's
much more so now that the check is in a completely different file than
the "show" functions that need the space.

> +	if (len >= (PAGE_SIZE - 1))
> +		return -EINVAL;