linux-kernel - Re: [PATCH] USB: core: Improve unlocking of a mutex in two functions

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Date:   Sun, 5 Nov 2017 09:29:22 +0100
From:   SF Markus Elfring <elfring@...rs.sourceforge.net>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        linux-usb@...r.kernel.org, kernel-janitors@...r.kernel.org
Cc:     Alan Stern <stern@...land.harvard.edu>,
        Eugene Korenevsky <ekorenevsky@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Günter Röck <linux@...ck-us.net>,
        Jaejoong Kim <climbbb.kim@...il.com>,
        Johan Hovold <johan@...nel.org>,
        Jonathan Corbet <corbet@....net>,
        Mathias Nyman <mathias.nyman@...ux.intel.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] USB: core: Improve unlocking of a mutex in two functions

>> @@ -5529,8 +5528,7 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
>>                 dev_err(&udev->dev,
>>                         "can't restore configuration #%d (error=%d)\n",
>>                         udev->actconfig->desc.bConfigurationValue, ret);
>> -               mutex_unlock(hcd->bandwidth_mutex);
>> -               goto re_enumerate;
>> +               goto unlock;
>>         }
>>         mutex_unlock(hcd->bandwidth_mutex);
>>         usb_set_device_state(udev, USB_STATE_CONFIGURED);
>> @@ -5583,6 +5581,8 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
>>         udev->bos = bos;
>>         return 0;
>>
>> +unlock:
>> +       mutex_unlock(hcd->bandwidth_mutex);
> 
> This makes it harder for the reader,

I am curious if the view on the preferred code readability can be clarified further.


> as the mutex_unlock() is now far below the block
> of code that's protected by the lock.

I got an other software development opinion for this aspect.
Can the label be clear enough about the shown purpose already?

Regards,
Markus