Hi Hans,
On Mon, Aug 22, 2016 at 02:40:39PM +0200, Hans Verkuil wrote:
> On 08/19/2016 12:23 PM, Sakari Ailus wrote:
> > devm functions are fine for managing resources that are directly related
> > to the device at hand and that have no other dependencies. However, a
> > process holding a file handle to a device created by a driver for a device
> > may result in the file handle left behind after the device is long gone.
> > This will result in accessing released (and potentially reallocated)
> > memory.
> >
> > Instead, rely on the media device which will stick around until all users
> > are gone.
> >
> > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > ---
> > drivers/media/platform/omap3isp/isp.c | 38 ++++++++++++++++++++-------
> > drivers/media/platform/omap3isp/ispccp2.c | 3 ++-
> > drivers/media/platform/omap3isp/isph3a_aewb.c | 20 +++++++++-----
> > drivers/media/platform/omap3isp/isph3a_af.c | 20 +++++++++-----
> > drivers/media/platform/omap3isp/isphist.c | 5 ++--
> > drivers/media/platform/omap3isp/ispstat.c | 2 ++
> > 6 files changed, 63 insertions(+), 25 deletions(-)
> >
> > diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
> > index 217d4da..3488ed3 100644
> > --- a/drivers/media/platform/omap3isp/isp.c
> > +++ b/drivers/media/platform/omap3isp/isp.c
> > @@ -1370,7 +1370,7 @@ static int isp_get_clocks(struct isp_device *isp)
> > unsigned int i;
> >
> > for (i = 0; i < ARRAY_SIZE(isp_clocks); ++i) {
> > - clk = devm_clk_get(isp->dev, isp_clocks[i]);
>
> I wonder, would it be possible to use the media device itself for these devm_
> functions? Since the media device is the last one to be released...
Do you happen to mean... struct media_device->devnode.dev?
Interesting idea, I can't see why not. That'd actually make the required
driver changes to fix the drivers quite a bit easier to make. And we could
still use devm_() functions.
--
Regards,
Sakari Ailus
e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
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