linux-kernel - Re: [RESEND PATCH v2 5/7] usb: xhci: plat: Remove checks for optional clock in error/remove path

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Message-ID: <20160427143343.6510ff57@xhacker>
Date:	Wed, 27 Apr 2016 14:33:43 +0800
From:	Jisheng Zhang <jszhang@...vell.com>
To:	Felipe Balbi <felipe.balbi@...ux.intel.com>,
	<mathias.nyman@...ux.intel.com>
CC:	<gregkh@...uxfoundation.org>, <linux-usb@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<yendapally.reddy@...adcom.com>
Subject: Re: [RESEND PATCH v2 5/7] usb: xhci: plat: Remove checks for
 optional clock in error/remove path

Dear Felipe,

On Wed, 27 Apr 2016 08:33:52 +0300 Felipe Balbi wrote:

> Jisheng Zhang <jszhang@...vell.com> writes:
> > Commit 63589e92c2d9 ("clk: Ignore error and NULL pointers passed to
> > clk_{unprepare, disable}()") allows NULL or error pointer to be passed
> > unconditionally.
> >
> > This patch is to simplify probe error and remove code paths.  
> 
> this seems wrong to me. xhci->clk isn't initialized to NULL, it's either
> initialized to a valid struct clk * or some ERR_PTR() value.

Commit 63589e92c2d9 could also ignore error value ;)

> 
> Care to explain ?
> 
> > Signed-off-by: Jisheng Zhang <jszhang@...vell.com>
> > ---
> >  drivers/usb/host/xhci-plat.c | 6 ++----
> >  1 file changed, 2 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> > index 0e69712..83669d0 100644
> > --- a/drivers/usb/host/xhci-plat.c
> > +++ b/drivers/usb/host/xhci-plat.c
> > @@ -266,8 +266,7 @@ put_usb3_hcd:
> >  	usb_put_hcd(xhci->shared_hcd);
> >  
> >  disable_clk:
> > -	if (!IS_ERR(clk))
> > -		clk_disable_unprepare(clk);
> > +	clk_disable_unprepare(clk);
> >  
> >  put_hcd:
> >  	usb_put_hcd(hcd);
> > @@ -287,8 +286,7 @@ static int xhci_plat_remove(struct platform_device *dev)
> >  	usb_remove_hcd(hcd);
> >  	usb_put_hcd(xhci->shared_hcd);
> >  
> > -	if (!IS_ERR(clk))
> > -		clk_disable_unprepare(clk);
> > +	clk_disable_unprepare(clk);
> >  	usb_put_hcd(hcd);
> >  
> >  	return 0;
> > -- 
> > 2.8.1
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-usb" in
> > the body of a message to majordomo@...r.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html  
>