[PATCH] Fix warning and undefined behavior in mmc voltage handling

[PATCH] Fix warning and undefined behavior in mmc voltage handling

[Pavel Machek]

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!voltage_ranges is tested for too late, allowing warning and undefined
behavior. Fix that.

Signed-off-by: Pavel Machek <pavel@ucw.cz>

---

Plus I guess author should add parenthesis in the expression. a / b /
c is _not_ common idiom.

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 3a4402a..b3fa9c9 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -363,11 +363,11 @@ int mmc_of_parse_voltage(struct device_node *np, u32 *mask)
 	int num_ranges, i;
 
 	voltage_ranges = of_get_property(np, "voltage-ranges", &num_ranges);
-	num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
 	if (!voltage_ranges) {
 		pr_debug("%pOF: voltage-ranges unspecified\n", np);
 		return 0;
 	}
+	num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
 	if (!num_ranges) {
 		pr_err("%pOF: voltage-ranges empty\n", np);
 		return -EINVAL;

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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Re: [PATCH] Fix warning and undefined behavior in mmc voltage handling

[Ulf Hansson]

On Fri, 12 Apr 2019 at 11:34, Pavel Machek <pavel@ucw.cz> wrote:
>
> !voltage_ranges is tested for too late, allowing warning and undefined
> behavior. Fix that.
>
> Signed-off-by: Pavel Machek <pavel@ucw.cz>

Pavel, thanks for your patch.

Would you mind re-posting to linux-mmc so I can get it into the
patchtracker. Please also change the prefix of the header to "mmc:
core:".

Otherwise this looks good to me.

Kind regards
Uffe

>
> ---
>
> Plus I guess author should add parenthesis in the expression. a / b /
> c is _not_ common idiom.
>
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index 3a4402a..b3fa9c9 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -363,11 +363,11 @@ int mmc_of_parse_voltage(struct device_node *np, u32 *mask)
>         int num_ranges, i;
>
>         voltage_ranges = of_get_property(np, "voltage-ranges", &num_ranges);
> -       num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
>         if (!voltage_ranges) {
>                 pr_debug("%pOF: voltage-ranges unspecified\n", np);
>                 return 0;
>         }
> +       num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
>         if (!num_ranges) {
>                 pr_err("%pOF: voltage-ranges empty\n", np);
>                 return -EINVAL;
>
> --
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: [PATCH] Fix warning and undefined behavior in mmc voltage handling

[Pavel Machek]

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On Tue 2019-04-16 09:48:51, Ulf Hansson wrote:
> On Fri, 12 Apr 2019 at 11:34, Pavel Machek <pavel@ucw.cz> wrote:
> >
> > !voltage_ranges is tested for too late, allowing warning and undefined
> > behavior. Fix that.
> >
> > Signed-off-by: Pavel Machek <pavel@ucw.cz>
> 
> Pavel, thanks for your patch.
> 
> Would you mind re-posting to linux-mmc so I can get it into the
> patchtracker. Please also change the prefix of the header to "mmc:
> core:".

Done.

> > Plus I guess author should add parenthesis in the expression. a / b /
> > c is _not_ common idiom.

Can you do something about the a / b / c situation?

> > -       num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
> > +       num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;

I guess it is:
       num_ranges = (num_ranges / sizeof(*voltage_ranges)) / 2;

...but...

									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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Re: [PATCH] Fix warning and undefined behavior in mmc voltage handling

[Ulf Hansson]

On Tue, 16 Apr 2019 at 10:00, Pavel Machek <pavel@ucw.cz> wrote:
>
> On Tue 2019-04-16 09:48:51, Ulf Hansson wrote:
> > On Fri, 12 Apr 2019 at 11:34, Pavel Machek <pavel@ucw.cz> wrote:
> > >
> > > !voltage_ranges is tested for too late, allowing warning and undefined
> > > behavior. Fix that.
> > >
> > > Signed-off-by: Pavel Machek <pavel@ucw.cz>
> >
> > Pavel, thanks for your patch.
> >
> > Would you mind re-posting to linux-mmc so I can get it into the
> > patchtracker. Please also change the prefix of the header to "mmc:
> > core:".
>
> Done.

Thanks!

>
> > > Plus I guess author should add parenthesis in the expression. a / b /
> > > c is _not_ common idiom.
>
> Can you do something about the a / b / c situation?

Sure.

>
> > > -       num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
> > > +       num_ranges = num_ranges / sizeof(*voltage_ranges) / 2;
>
> I guess it is:
>        num_ranges = (num_ranges / sizeof(*voltage_ranges)) / 2;

Just send a patch on top, then I will apply it.

Kind regards
Uffe