linux-kernel - Re: [PATCH] p54: Fix an error handling path in p54spi

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Message-ID: <59fdf712-5825-9c0d-ee28-7b6b485d96bd@wanadoo.fr>
Date:   Sun, 12 Jun 2022 23:02:50 +0200
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     Christian Lamparter <chunkeey@...il.com>
Cc:     Kalle Valo <kvalo@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        "John W. Linville" <linville@...driver.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org,
        Christian Lamparter <chunkeey@....de>,
        linux-wireless <linux-wireless@...r.kernel.org>,
        Netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH] p54: Fix an error handling path in p54spi_probe()

Le 12/06/2022 à 22:45, Christian Lamparter a écrit :
> Hi,
> 
> On Sun, Jun 12, 2022 at 9:55 PM Christophe JAILLET
> <christophe.jaillet@...adoo.fr> wrote:
>>
>> If an error occurs after a successful call to p54spi_request_firmware(), it
>> must be undone by a corresponding release_firmware()
> 
> Yes, good catch. That makes sense.
> 
>> as already done in the error handling path of p54spi_request_firmware() and in
>> the .remove() function.
>>
>> Add the missing call in the error handling path and update some goto
>> label accordingly.
> 
>  From what I know, "release_firmware(some *fw)" includes a check for
> *fw != NULL already.

Correct.

> 
> we could just add a single release_firmware(priv->firmware) to any of the error

Not my favorite style, but if it is preferred this way, NP.

> paths labels (i.e.: err_free_common) and then we remove the extra
> release_firmware(...) in p54spi_request_firmware so that we don't try to free
> it twice.

Sure. I'll add a comment to explain where is is released in case of error.

> 
> (This also skips the need for having "err_release_firmaware" .. which
> unfortunately has a small typo)
> 
> Regards,
> Christian
> 
>> Fixes: cd8d3d321285 ("p54spi: p54spi driver")
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
>> ---
>>   drivers/net/wireless/intersil/p54/p54spi.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/wireless/intersil/p54/p54spi.c b/drivers/net/wireless/intersil/p54/p54spi.c
>> index f99b7ba69fc3..679ac164c994 100644
>> --- a/drivers/net/wireless/intersil/p54/p54spi.c
>> +++ b/drivers/net/wireless/intersil/p54/p54spi.c
>> @@ -650,14 +650,16 @@ static int p54spi_probe(struct spi_device *spi)
>>
>>          ret = p54spi_request_eeprom(hw);
>>          if (ret)
>> -               goto err_free_common;
>> +               goto err_release_firmaware;
>>
>>          ret = p54_register_common(hw, &priv->spi->dev);
>>          if (ret)
>> -               goto err_free_common;
>> +               goto err_release_firmaware;
>>
>>          return 0;
>>
>> +err_release_firmaware:
>> +       release_firmware(priv->firmware);
>>   err_free_common:
>>          free_irq(gpio_to_irq(p54spi_gpio_irq), spi);
>>   err_free_gpio_irq:
>> --
>> 2.34.1
>>
>