linux-kernel - Re: [PATCH v2 1/2] clk: Add of_clk_get_by_name

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Date:   Mon, 30 Jul 2018 13:57:07 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Phil Edworthy <phil.edworthy@...esas.com>
Cc:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Simon Horman <horms@...ge.net.au>,
        linux-clk <linux-clk@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2 1/2] clk: Add of_clk_get_by_name_optional() function

On Mon, 2018-07-30 at 10:55 +0200, Geert Uytterhoeven wrote:
> On Mon, Jul 30, 2018 at 10:36 AM Phil Edworthy
> <phil.edworthy@...esas.com> wrote:

> > +struct clk *of_clk_get_by_name_optional(struct device_node *np,
> > +                                       const char *name)
> > +{
> > +       if (!np)
> > +               return ERR_PTR(-ENOENT);
> 
> Shouldn't this return NULL?
> Or let __of_clk_get_by_name() handle that (cfr. above)?
> 
> Hmm, of_clk_get_by_name() has a similar check, while the current
> __of_clk_get_by_name() already handle np == NULL, too.

This check is needed to prevent NULL pointer dereference below.

And I agree that absence of device node should be considered as okay
case for optional clock (!CONFIG_OF case, for example).

> > +
> > +       return __of_clk_get_by_name(np, np->full_name, name, true);
> > +}

-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy