Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH] net: dsa: lan9303: correctly check return value of
 devm_gpiod_get_optional
To:     Pan Bian <bianpan2016@163.com>, Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@savoirfairelinux.com>,
        Florian Fainelli <f.fainelli@gmail.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
References: <1510501089-9451-1-git-send-email-bianpan2016@163.com>
From:   Phil Reid <preid@electromag.com.au>
Message-ID: <251e5e33-8bbb-d745-63c8-95d7b34d95f0@electromag.com.au>
Date:   Mon, 13 Nov 2017 12:08:49 +0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101
 Thunderbird/52.4.0
MIME-Version: 1.0
In-Reply-To: <1510501089-9451-1-git-send-email-bianpan2016@163.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-AU
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 12/11/2017 23:38, Pan Bian wrote:
> Function devm_gpiod_get_optional() returns an ERR_PTR on failure. Its
> return value should not be validated by a NULL check. Instead, use IS_ERR.
> 
> Signed-off-by: Pan Bian <bianpan2016@163.com>
> ---
>   drivers/net/dsa/lan9303-core.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/dsa/lan9303-core.c b/drivers/net/dsa/lan9303-core.c
> index b471413..6d3fc8f 100644
> --- a/drivers/net/dsa/lan9303-core.c
> +++ b/drivers/net/dsa/lan9303-core.c
> @@ -828,7 +828,7 @@ static void lan9303_probe_reset_gpio(struct lan9303 *chip,
>   	chip->reset_gpio = devm_gpiod_get_optional(chip->dev, "reset",
>   						   GPIOD_OUT_LOW);
>   
> -	if (!chip->reset_gpio) {
> +	if (IS_ERR(chip->reset_gpio)) {
>   		dev_dbg(chip->dev, "No reset GPIO defined\n");
>   		return;
>   	}
> 
Should not an error actually report the error and error out (ie fail probe).
But a null is the optional return and ok. (ie when -ENOENT return from sub gpiod_get call).

IS_ERR should be a separate condition check I think.

related lan9303_handle_reset() always returns 0.

lan9303_probe checks  lan9303_handle_reset() return value.

Probably should be checking lan9303_probe_reset_gpio() instead.

-- 
Regards
Phil Reid

From 1583886067017678448@xxx Sun Nov 12 18:31:02 +0000 2017
X-GM-THRID: 1583875313307114870
X-Gmail-Labels: Inbox,Category Forums,HistoricalUnread