On Fri, 15 Jul 2016 20:32:24 +0900
Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, Jul 15, 2016 at 02:34:00PM +0530, Anup Patel wrote:
> > From: Jan Viktorin <viktorin@xxxxxxxxxxxxxx>
> >
> > The variable i contains a total number of resources (including
> > IORESOURCE_IRQ). However, we want the dmem_region_start to point
> > after the last resource of type IORESOURCE_MEM. The original behaviour
> > leads (very likely) to skipping several UIO mapping regions and makes
> > them useless. Fix this by computing dmem_region_start from the uiomem
> > which points to the last used UIO mapping.
> >
> > Fixes: 0a0c3b5a24bd ("Add new uio device for dynamic memory allocation")
> >
> > Signed-off-by: Jan Viktorin <viktorin@xxxxxxxxxxxxxx>
> > ---
> > drivers/uio/uio_dmem_genirq.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Why isn't this patch first in the series, with a stable marking, and
> your signed off on it (you are forwarding it on to me, so you need to
> add your mark to it as well, I can't take it otherwise.)
>
> > diff --git a/drivers/uio/uio_dmem_genirq.c b/drivers/uio/uio_dmem_genirq.c
> > index 915facb..e1134a4 100644
> > --- a/drivers/uio/uio_dmem_genirq.c
> > +++ b/drivers/uio/uio_dmem_genirq.c
> > @@ -229,7 +229,7 @@ static int uio_dmem_genirq_probe(struct platform_device *pdev)
> > ++uiomem;
> > }
> >
> > - priv->dmem_region_start = i;
> > + priv->dmem_region_start = uiomem - &uioinfo->mem[0];
>
> Are you sure about this? It doesn't look correct at first glance, I'm
The loop over resources counts all resources in _i_ and mem resources in _uiomem_
pointer. Thus, the dmem_region_start cannot be derived from _i_ but from _uiomem_.
> loath to take this without a bunch of testing. Were you able to test
> this out to verify it doesn't break working hardware?
This is a good point, however, what is the working hardware? I could not find
any application of the uio_dmem_genirq anywhere online. Any example, nothing.
I am afraid that nobody is using more then 1 memory resource with this driver
and so nobody could discover this to be a bug. I was working with more then 2
resources.
I'd be glad if somebody else can test it on any other working setup.
Regards
Jan
>
> thanks,
>
> greg k-h
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