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From:   Bartosz Golaszewski <brgl@bgdev.pl>
Date:   Wed, 20 Jun 2018 09:56:58 +0200
Message-ID: <CAMRc=MdUTV3ZgBA-5vBgsCWCGTKnq_7=ZEA7_9gEsJHRmXDfhg@mail.gmail.com>
Subject: Re: [PATCH 1/3] net: ethernet: fix suspend/resume in davinci_emac
To:     Florian Fainelli <f.fainelli@gmail.com>
Cc:     Grygorii Strashko <grygorii.strashko@ti.com>,
        "David S . Miller" <davem@davemloft.net>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>,
        Rob Herring <robh@kernel.org>, Lukas Wunner <lukas@wunner.de>,
        Kevin Hilman <khilman@kernel.org>,
        David Lechner <david@lechnology.com>,
        Sekhar Nori <nsekhar@ti.com>, Andrew Lunn <andrew@lunn.ch>,
        linux-omap@vger.kernel.org, netdev@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        stable <stable@vger.kernel.org>
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2018-06-19 18:55 GMT+02:00 Florian Fainelli <f.fainelli@gmail.com>:
> On 06/19/2018 09:09 AM, Bartosz Golaszewski wrote:
>> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>>
>> This patch reverts commit 3243ff2a05ec ("net: ethernet: davinci_emac:
>> Deduplicate bus_find_device() by name matching") and adds a comment
>> which should stop anyone from reintroducing the same "fix" in the future.
>>
>> We can't use bus_find_device_by_name() here because the device name is
>> not guaranteed to be 'davinci_mdio'. On some systems it can be
>> 'davinci_mdio.0' so we need to use strncmp() against the first part of
>> the string to correctly match it.
>>
>> Fixes: 3243ff2a05ec ("net: ethernet: davinci_emac: Deduplicate bus_find_device() by name matching")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>> ---
>>  drivers/net/ethernet/ti/davinci_emac.c | 15 +++++++++++++--
>>  1 file changed, 13 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/ti/davinci_emac.c b/drivers/net/ethernet/ti/davinci_emac.c
>> index 06d7c9e4dcda..a1a6445b5a7e 100644
>> --- a/drivers/net/ethernet/ti/davinci_emac.c
>> +++ b/drivers/net/ethernet/ti/davinci_emac.c
>> @@ -1385,6 +1385,11 @@ static int emac_devioctl(struct net_device *ndev, struct ifreq *ifrq, int cmd)
>>               return -EOPNOTSUPP;
>>  }
>>
>> +static int match_first_device(struct device *dev, void *data)
>> +{
>> +     return !strncmp(dev_name(dev), "davinci_mdio", 12);
>
>         const char *bus_name = "davinci_mdio";
>
>         return !strncmp(dev_name(dev), bus_name, strlen(bus_name));
>
> Or even better yet, if you want to make sure this really is a PHY device
> that you are trying to match, you could try to use sscanf() with PHY_ID_FMT.
> --
> Florian

I don't think this is necessary. This simple function would get too
complicated with the additional buffer for the sscanf'ed phy name etc.

Thanks,
Bart