On Sunday, November 14, 2010 22:53:29 Arnd Bergmann wrote:
> On Sunday 14 November 2010, Hans Verkuil wrote:
> > This patch series converts 24 v4l drivers to unlocked_ioctl. These are low
> > hanging fruit but you have to start somewhere :-)
> >
> > The first patch replaces mutex_lock in the V4L2 core by
> > mutex_lock_interruptible
> > for most fops.
>
> The patches all look good as far as I can tell, but I suppose the title is
> obsolete now that the BKL has been replaced with a v4l-wide mutex, which
> is what you are removing in the series.
I guess I have to rename it, even though strictly speaking the branch I'm
working in doesn't have your patch merged yet.
BTW, replacing the BKL with a static mutex is rather scary: the BKL gives up
the lock whenever you sleep, the mutex doesn't. Since sleeping is very common
in V4L (calling VIDIOC_DQBUF will typically sleep while waiting for a new frame
to arrive), this will make it impossible for another process to access *any*
v4l2 device node while the ioctl is sleeping.
I am not sure whether that is what you intended. Or am I missing something?
Regards,
Hans
--
Hans Verkuil - video4linux developer - sponsored by Cisco
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