Re: [PATCH] soc/tegra: refactor soc_is_tegra()

From: Thierry Reding
Date: Wed Nov 21 2018 - 09:43:26 EST


On Wed, Nov 21, 2018 at 02:34:57PM +0000, Jon Hunter wrote:
>
> On 21/11/2018 14:12, Yangtao Li wrote:
> > of_find_node_by_path() acquires a reference to the node returned by
> > it and that reference needs to be dropped by its caller.soc_is_tegra()
> > doesn't do that, so fix it.Call of_machine_is_compatible() to refactor
> > soc_is_tegra() whcih automatically manages the reference count.
> >
> > Signed-off-by: Yangtao Li <tiny.windzz@xxxxxxxxx>
> > ---
> > drivers/soc/tegra/common.c | 12 +++++++-----
> > 1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/soc/tegra/common.c b/drivers/soc/tegra/common.c
> > index cd8f41351add..0b40700b672a 100644
> > --- a/drivers/soc/tegra/common.c
> > +++ b/drivers/soc/tegra/common.c
> > @@ -22,11 +22,13 @@ static const struct of_device_id tegra_machine_match[] = {
> >
> > bool soc_is_tegra(void)
> > {
> > - struct device_node *root;
> > + struct of_device_id *match = tegra_machine_match;
> >
> > - root = of_find_node_by_path("/");
> > - if (!root)
> > - return false;
> > + while(match->compatible){
> > + if(of_machine_is_compatible(match->compatible))
> > + return true;
> > + match++;
> > + }
> >
> > - return of_match_node(tegra_machine_match, root) != NULL;
> > + return false;
> > }
>
> Ugh ... sorry, I thought that of_machine_is_compatible() looped through
> the matches. OK, let's stick with your initial fix.

Actually I prefer this one. Even if it is slightly more verbose, I think
it's much clearer what's actually going on. Also this hides all of the
OF node reference counting in a core function, so it's worth the extra
line, in my opinion.

Thierry

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