Messages in this thread | | | Date | Fri, 8 Apr 2016 12:06:00 +0200 | From | Ralf Baechle <> | Subject | Re: [PATCH v2] clk: let clk_disable() return immediately if clk is NULL or error |
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On Thu, Apr 07, 2016 at 05:33:28PM -0700, Stephen Boyd wrote:
> On 04/05, Masahiro Yamada wrote: > > The clk_disable() in the common clock framework (drivers/clk/clk.c) > > returns immediately if a given clk is NULL or an error pointer. It > > allows clock consumers to call clk_disable() without IS_ERR_OR_NULL > > checking if drivers are only used with the common clock framework. > > > > Unfortunately, NULL/error checking is missing from some of non-common > > clk_disable() implementations. This prevents us from completely > > dropping NULL/error checking from callers. Let's make it tree-wide > > consistent by adding IS_ERR_OR_NULL(clk) to all callees. > > > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > > Acked-by: Greg Ungerer <gerg@uclinux.org> > > Acked-by: Wan Zongshun <mcuos.com@gmail.com> > > --- > > > > Stephen, > > > > This patch has been unapplied for a long time. > > > > Please let me know if there is something wrong with this patch. > > > > I'm mostly confused why we wouldn't want to encourage people to > call clk_disable or unprepare on a clk that's an error pointer. > Typically an error pointer should be dealt with, instead of > silently ignored, so why wasn't it dealt with by passing it up > the probe() path?
While your argument makes perfect sense, Many clk_disable implementations are already doing similar checks, for example:
arch/arm/mach-davinci/clock.c:
void clk_disable(struct clk *clk) { unsigned long flags;
if (clk == NULL || IS_ERR(clk)) return; [...]
arch/arm/mach-omap1/clock.c
void clk_disable(struct clk *clk) { unsigned long flags;
if (clk == NULL || IS_ERR(clk)) return; [...]
arch/avr32/mach-at32ap/clock.c
void clk_disable(struct clk *clk) { unsigned long flags;
if (IS_ERR_OR_NULL(clk)) return; [...]
arch/mips/lantiq/clk.c:
static inline int clk_good(struct clk *clk) { return clk && !IS_ERR(clk); }
[...]
void clk_disable(struct clk *clk) { if (unlikely(!clk_good(clk))) return;
if (clk->disable) [...]
So should we go and weed out these checks?
Ralf
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