Re: [PATCH] dvb-core: Fix potential mutex_unlock without mutex_lockin dvb_dvr_read

From: Andrew Morton
Date: Thu Apr 30 2009 - 17:52:07 EST


On Thu, 30 Apr 2009 22:42:06 +0100
Simon Arlott <simon@xxxxxxxxxxx> wrote:

> >> diff --git a/drivers/media/dvb/dvb-core/dmxdev.c b/drivers/media/dvb/dvb-core/dmxdev.c
> >> index c35fbb8..d6d098a 100644
> >> --- a/drivers/media/dvb/dvb-core/dmxdev.c
> >> +++ b/drivers/media/dvb/dvb-core/dmxdev.c
> >> @@ -247,7 +247,7 @@ static ssize_t dvb_dvr_read(struct file *file, char __user *buf, size_t count,
> >> int ret;
> >>
> >> if (dmxdev->exit) {
> >> - mutex_unlock(&dmxdev->mutex);
> >> + //mutex_unlock(&dmxdev->mutex);
> >> return -ENODEV;
> >> }
> >
> > Is there any value in retaining all the commented-out lock operations,
> > or can we zap 'em?
>
> I'm assuming they should really be there - it's just not practical
> because the call to dvb_dmxdev_buffer_read is likely to block waiting
> for data.

well.. such infomation is much better communicated via a nice comment,
rather than mystery-dead-code?

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