linux-kernel - Re: [PATCH v2] clk: let clk_disable() return immediately if clk is NULL or error

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Date:	Thu, 7 Apr 2016 17:33:28 -0700
From:	Stephen Boyd <sboyd@...eaurora.org>
To:	Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc:	linux-clk@...r.kernel.org, Ralf Baechle <ralf@...ux-mips.org>,
	Michael Turquette <mturquette@...libre.com>,
	linux-mips@...ux-mips.org, linux-sh@...r.kernel.org,
	Haojian Zhuang <haojian.zhuang@...il.com>,
	Eric Miao <eric.y.miao@...il.com>,
	Hartley Sweeten <hsweeten@...ionengravers.com>,
	Greg Ungerer <gerg@...inux.org>,
	Ryan Mallon <rmallon@...il.com>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Steven Miao <realmz6@...il.com>,
	Simon Horman <horms@...ge.net.au>,
	Wan ZongShun <mcuos.com@...il.com>,
	Rich Felker <dalias@...c.org>,
	Yoshinori Sato <ysato@...rs.sourceforge.jp>,
	adi-buildroot-devel@...ts.sourceforge.net,
	Russell King <linux@....linux.org.uk>,
	linux-m68k@...ts.linux-m68k.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-renesas-soc@...r.kernel.org,
	Magnus Damm <magnus.damm@...il.com>,
	John Crispin <blogic@...nwrt.org>
Subject: Re: [PATCH v2] clk: let clk_disable() return immediately if clk is
 NULL or error

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@...ionext.com>
> Acked-by: Greg Ungerer <gerg@...inux.org>
> Acked-by: Wan Zongshun <mcuos.com@...il.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?

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