linux-kernel - Re: [PATCH] usb: misc: usb3503: call clk_disable

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Date:   Thu, 8 Sep 2022 14:01:15 +0800
From:   Dongliang Mu <mudongliangabcd@...il.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Dongliang Mu <dzm91@...t.edu.cn>, USB <linux-usb@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] usb: misc: usb3503: call clk_disable_unprepare in the
 error handling

On Wed, Sep 7, 2022 at 10:25 PM Greg Kroah-Hartman
<gregkh@...uxfoundation.org> wrote:
>
> On Sat, Sep 03, 2022 at 03:15:40PM +0800, Dongliang Mu wrote:
> > From: Dongliang Mu <mudongliangabcd@...il.com>
> >
> > Smatch reports the following warning:
> >
> > vers/usb/misc/usb3503.c:267 usb3503_probe() warn: 'hub->clk'
> > from clk_prepare_enable() not released on lines: 240,246,252
> >
> > Fix this by adding a flag to indicate if hub->clk is prepared or not and
> > invoke clk_disable_unprepare in the error handling.
> >
> > Signed-off-by: Dongliang Mu <mudongliangabcd@...il.com>
> > ---
> >  drivers/usb/misc/usb3503.c | 18 +++++++++++++++---
> >  1 file changed, 15 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/usb/misc/usb3503.c b/drivers/usb/misc/usb3503.c
> > index 330f494cd158..add47dd964b2 100644
> > --- a/drivers/usb/misc/usb3503.c
> > +++ b/drivers/usb/misc/usb3503.c
> > @@ -160,6 +160,7 @@ static int usb3503_probe(struct usb3503 *hub)
> >       struct usb3503_platform_data *pdata = dev_get_platdata(dev);
> >       struct device_node *np = dev->of_node;
> >       int err;
> > +     int is_clk_enable = 0;
>
> bool?
>
> >       u32 mode = USB3503_MODE_HUB;
> >       const u32 *property;
> >       enum gpiod_flags flags;
> > @@ -217,6 +218,8 @@ static int usb3503_probe(struct usb3503 *hub)
> >                       return err;
> >               }
> >
> > +             // set a flag for successful clk_prepare_enable
>
> Comment isn't needed.
>
> > +             is_clk_enable = 1;
> >               property = of_get_property(np, "disabled-ports", &len);
> >               if (property && (len / sizeof(u32)) > 0) {
> >                       int i;
> > @@ -236,20 +239,29 @@ static int usb3503_probe(struct usb3503 *hub)
> >       else
> >               flags = GPIOD_OUT_HIGH;
> >       hub->intn = devm_gpiod_get_optional(dev, "intn", flags);
> > -     if (IS_ERR(hub->intn))
> > +     if (IS_ERR(hub->intn)) {
> > +             if (is_clk_enable)
> > +                     clk_disable_unprepare(hub->clk);
> >               return PTR_ERR(hub->intn);
>
> This is getting messy, any way to make a common error handler at the
> bottom of the function instead?  That's the common kernel coding style
> for this type of thing.

I have addressed all the issues mentioned above:
1. change is_clk_enable to is_clk_enabled, and change its type to bool.
2. remove the comment and move the error handling code to the end of
probe function.
>
> thanks,
>
> greg k-h