Subject: [PATCH] clk: let clk_disable() return immediately if clk is NULL or error

From: [email-masked] (Greg Ungerer)
Date: Thu, 10 Dec 2015 19:40:21 +1000

Hi Masahiro,

On 05/12/15 16:17, Masahiro Yamada wrote:
> The clk_disable() in the common clock framework (drivers/clk/clk.c)
> returns immediately if the given clk is NULL or an error pointer.
> It allows drivers to call clk_disable() (and clk_disable_unprepare())
> with a clock that might be NULL or an error pointer as long as the
> drivers are only used along 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 from callers.  Let's add IS_ERR_OR_NULL(clk)
> checks to all callees.
>
> Signed-off-by: Masahiro Yamada <[email-masked]>

I have no problems with the m68k/coldfire change:

Acked-by: Greg Ungerer <[email-masked]>

Regards
Greg

> ---
>
>  arch/arm/mach-ep93xx/clock.c     |  2 +-
>  arch/arm/mach-lpc32xx/clock.c    |  3 +++
>  arch/arm/mach-mmp/clock.c        |  3 +++
>  arch/arm/mach-sa1100/clock.c     | 15 ++++++++-------
>  arch/arm/mach-w90x900/clock.c    |  3 +++
>  arch/blackfin/mach-bf609/clock.c |  3 +++
>  arch/m68k/coldfire/clk.c         |  4 ++++
>  arch/mips/bcm63xx/clk.c          |  3 +++
>  arch/mips/lantiq/clk.c           |  3 +++
>  drivers/sh/clk/core.c            |  2 +-
>  10 files changed, 32 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm/mach-ep93xx/clock.c b/arch/arm/mach-ep93xx/clock.c
> index 39ef3b6..4e11f7d 100644
> --- a/arch/arm/mach-ep93xx/clock.c
> +++ b/arch/arm/mach-ep93xx/clock.c
> @@ -293,7 +293,7 @@ void clk_disable(struct clk *clk)
>  {
>  	unsigned long flags;
>
> -	if (!clk)
> +	if (IS_ERR_OR_NULL(clk))
>  		return;
>
>  	spin_lock_irqsave(&clk_lock, flags);
> diff --git a/arch/arm/mach-lpc32xx/clock.c b/arch/arm/mach-lpc32xx/clock.c
> index 661c8f4..07faac2 100644
> --- a/arch/arm/mach-lpc32xx/clock.c
> +++ b/arch/arm/mach-lpc32xx/clock.c
> @@ -1125,6 +1125,9 @@ void clk_disable(struct clk *clk)
>  {
>  	unsigned long flags;
>
> +	if (IS_ERR_OR_NULL(clk))
> +		return;
> +
>  	spin_lock_irqsave(&global_clkregs_lock, flags);
>  	local_clk_disable(clk);
>  	spin_unlock_irqrestore(&global_clkregs_lock, flags);
> diff --git a/arch/arm/mach-mmp/clock.c b/arch/arm/mach-mmp/clock.c
> index 7c6f95f..7b33122 100644
> --- a/arch/arm/mach-mmp/clock.c
> +++ b/arch/arm/mach-mmp/clock.c
> @@ -67,6 +67,9 @@ void clk_disable(struct clk *clk)
>  {
>  	unsigned long flags;
>
> +	if (IS_ERR_OR_NULL(clk))
> +		return;
> +
>  	WARN_ON(clk->enabled == 0);
>
>  	spin_lock_irqsave(&clocks_lock, flags);
> diff --git a/arch/arm/mach-sa1100/clock.c b/arch/arm/mach-sa1100/clock.c
> index cbf53bb..ea103fd 100644
> --- a/arch/arm/mach-sa1100/clock.c
> +++ b/arch/arm/mach-sa1100/clock.c
> @@ -85,13 +85,14 @@ void clk_disable(struct clk *clk)
>  {
>  	unsigned long flags;
>
> -	if (clk) {
> -		WARN_ON(clk->enabled == 0);
> -		spin_lock_irqsave(&clocks_lock, flags);
> -		if (--clk->enabled == 0)
> -			clk->ops->disable(clk);
> -		spin_unlock_irqrestore(&clocks_lock, flags);
> -	}
> +	if (IS_ERR_OR_NULL(clk))
> +		return;
> +
> +	WARN_ON(clk->enabled == 0);
> +	spin_lock_irqsave(&clocks_lock, flags);
> +	if (--clk->enabled == 0)
> +		clk->ops->disable(clk);
> +	spin_unlock_irqrestore(&clocks_lock, flags);
>  }
>  EXPORT_SYMBOL(clk_disable);
>
> diff --git a/arch/arm/mach-w90x900/clock.c b/arch/arm/mach-w90x900/clock.c
> index 2c371ff..90ec250 100644
> --- a/arch/arm/mach-w90x900/clock.c
> +++ b/arch/arm/mach-w90x900/clock.c
> @@ -46,6 +46,9 @@ void clk_disable(struct clk *clk)
>  {
>  	unsigned long flags;
>
> +	if (IS_ERR_OR_NULL(clk))
> +		return;
> +
>  	WARN_ON(clk->enabled == 0);
>
>  	spin_lock_irqsave(&clocks_lock, flags);
> diff --git a/arch/blackfin/mach-bf609/clock.c b/arch/blackfin/mach-bf609/clock.c
> index 3783058..fed8015 100644
> --- a/arch/blackfin/mach-bf609/clock.c
> +++ b/arch/blackfin/mach-bf609/clock.c
> @@ -97,6 +97,9 @@ EXPORT_SYMBOL(clk_enable);
>
>  void clk_disable(struct clk *clk)
>  {
> +	if (IS_ERR_OR_NULL(clk))
> +		return;
> +
>  	if (clk->ops && clk->ops->disable)
>  		clk->ops->disable(clk);
>  }
> diff --git a/arch/m68k/coldfire/clk.c b/arch/m68k/coldfire/clk.c
> index fddfdcc..eb0e8c1 100644
> --- a/arch/m68k/coldfire/clk.c
> +++ b/arch/m68k/coldfire/clk.c
> @@ -101,6 +101,10 @@ EXPORT_SYMBOL(clk_enable);
>  void clk_disable(struct clk *clk)
>  {
>  	unsigned long flags;
> +
> +	if (IS_ERR_OR_NULL(clk))
> +		return;
> +
>  	spin_lock_irqsave(&clk_lock, flags);
>  	if ((--clk->enabled == 0) && clk->clk_ops)
>  		clk->clk_ops->disable(clk);
> diff --git a/arch/mips/bcm63xx/clk.c b/arch/mips/bcm63xx/clk.c
> index 6375652..d6a39bf 100644
> --- a/arch/mips/bcm63xx/clk.c
> +++ b/arch/mips/bcm63xx/clk.c
> @@ -326,6 +326,9 @@ EXPORT_SYMBOL(clk_enable);
>
>  void clk_disable(struct clk *clk)
>  {
> +	if (IS_ERR_OR_NULL(clk))
> +		return;
> +
>  	mutex_lock(&clocks_mutex);
>  	clk_disable_unlocked(clk);
>  	mutex_unlock(&clocks_mutex);
> diff --git a/arch/mips/lantiq/clk.c b/arch/mips/lantiq/clk.c
> index a0706fd..c8d87b1 100644
> --- a/arch/mips/lantiq/clk.c
> +++ b/arch/mips/lantiq/clk.c
> @@ -130,6 +130,9 @@ EXPORT_SYMBOL(clk_enable);
>
>  void clk_disable(struct clk *clk)
>  {
> +	if (IS_ERR_OR_NULL(clk))
> +		return;
> +
>  	if (unlikely(!clk_good(clk)))
>  		return;
>
> diff --git a/drivers/sh/clk/core.c b/drivers/sh/clk/core.c
> index be56b22..3dd20cf 100644
> --- a/drivers/sh/clk/core.c
> +++ b/drivers/sh/clk/core.c
> @@ -252,7 +252,7 @@ void clk_disable(struct clk *clk)
>  {
>  	unsigned long flags;
>
> -	if (!clk)
> +	if (IS_ERR_OR_NULL(clk))
>  		return;
>
>  	spin_lock_irqsave(&clock_lock, flags);
>