From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Hurley <peter@hurleysoftware.com>
Subject: Re: [PATCH v2 -next 10/13] serial: earlycon: Allow earlycon params
 with name only
Date: Thu, 05 Mar 2015 11:07:08 -0500
Message-ID: <54F87F2C.9070508@hurleysoftware.com>
References: <1425225958-17908-1-git-send-email-peter@hurleysoftware.com> <1425225958-17908-11-git-send-email-peter@hurleysoftware.com> <CAL_Jsq+bL4qB797M0s+ZHSSrh=d_7bhP2AZQxAbqjmp5Gd0MXg@mail.gmail.com> <54F87C15.6020801@hurleysoftware.com>
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Sender: linux-kernel-owner@vger.kernel.org
To: Rob Herring <robh@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Andrew Morton <akpm@linux-foundation.org>, Jiri Slaby <jslaby@suse.cz>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>
List-Id: linux-serial@vger.kernel.org

On 03/05/2015 10:53 AM, Peter Hurley wrote:
> On 03/05/2015 10:46 AM, Rob Herring wrote:
>> On Sun, Mar 1, 2015 at 10:05 AM, Peter Hurley <peter@hurleysoftware.com> wrote:
>>> Allow earlycon param strings of the form
>>>    earlycon=<name>
>>
>> Humm, that should already be the case with ARM semihosting (smh).
>>
>> Rob
> 
> Then it's passing a bogus options string to parse_options()

No, that's not right.

It's passing an empty string (the '\0' at the end) to parse_options()
which is failing with -EINVAL, which upon returning sets buf to NULL.

My way has less obfuscation but the commit log needs to change.

Regards,
Peter Hurley

>>>
>>> Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
>>> ---
>>>  drivers/tty/serial/earlycon.c | 11 +++++++----
>>>  1 file changed, 7 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
>>> index da5e8c8..025ea01 100644
>>> --- a/drivers/tty/serial/earlycon.c
>>> +++ b/drivers/tty/serial/earlycon.c
>>> @@ -109,13 +109,16 @@ int __init setup_earlycon(char *buf, const char *match,
>>>         len = strlen(match);
>>>         if (strncmp(buf, match, len))
>>>                 return 0;
>>> -       if (buf[len] && (buf[len] != ','))
>>> -               return 0;
>>>
>>> -       buf += len + 1;
>>> +       if (buf[len]) {
>>> +               if (buf[len] != ',')
>>> +                       return 0;
>>> +               buf += len + 1;
>>> +       } else
>>> +               buf = NULL;
>>>
>>>         /* On parsing error, pass the options buf to the setup function */
>>> -       if (!parse_options(&early_console_dev, buf))
>>> +       if (buf && !parse_options(&early_console_dev, buf))
>>>                 buf = NULL;
>>>
>>>         port->uartclk = BASE_BAUD * 16;
>>> --
>>> 2.3.0
>>>
>