Re: [PATCH 10/11] soc: ti: knav_qmss_queue: use of_property_read_bool

Julia Lawall
2016-08-05T12:59:22Z

On Fri, 5 Aug 2016, Robin Murphy wrote:

> Hi Julia,
>
> On 05/08/16 09:56, Julia Lawall wrote:
> > Use of_property_read_bool to check for the existence of a property.
>
> This caught my eye since Rob told me off for doing the same recently[1].
>
> > The semantic patch that makes this change is as follows:
> > (http://coccinelle.lip6.fr/)
> >
> > // <smpl>
> > @@
> > expression e1,e2;
> > statement S2,S1;
> > @@
> > - if (of_get_property(e1,e2,NULL))
> > + if (of_property_read_bool(e1,e2))
> > S1 else S2
> > // </smpl>
> >
> > Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
> >
> > ---
> > drivers/soc/ti/knav_qmss_queue.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/soc/ti/knav_qmss_queue.c b/drivers/soc/ti/knav_qmss_queue.c
> > index b73e353..56b5d7c 100644
> > --- a/drivers/soc/ti/knav_qmss_queue.c
> > +++ b/drivers/soc/ti/knav_qmss_queue.c
> > @@ -1240,7 +1240,7 @@ static int knav_setup_queue_range(struct knav_device *kdev,
> > if (of_get_property(node, "qalloc-by-id", NULL))
>
> According to the binding, "qalloc-by-id" _is_ a boolean property, so
> this one really does deserve to be of_property_read_bool()...
>
> > range->flags |= RANGE_RESERVED;
> >
> > - if (of_get_property(node, "accumulator", NULL)) {
> > + if (of_property_read_bool(node, "accumulator")) {
>
> ...whereas "accumulator" must have a value, so this isn't technically
> appropriate. In general, most of these "if the property exists, read the
> property and do stuff" checks are probably a sign of code that could be
> simplified by refactoring the "do stuff" step to just specifically
> handle the "read the property" step returning -EINVAL when it's not present.

Thanks for the very helpful feedback. I will rethink the patch set in
light of this information.

julia

> Robin.
>
> [1]:https://www.mail-archive.com/iommu@lists.linux-foundation.org/msg13375.html
>
> > ret = knav_init_acc_range(kdev, node, range);
> > if (ret < 0) {
> > devm_kfree(dev, range);
> >
> >
> > _______________________________________________
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> >
>
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