linux-kernel - Re: [PATCH 1/1] extcon: deduplicate code in extcon_set_state

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Date:   Thu, 16 Dec 2021 12:05:18 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     Alexander Stein <alexander.stein@...tq-group.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] extcon: deduplicate code in extcon_set_state_sync()

On 11/23/21 11:53 PM, Alexander Stein wrote:
> Finding the cable index and checking for changed status is also done
> in extcon_set_state(). So calling extcon_set_state_sync() will do these
> checks twice. Remove them and use these checks from extcon_set_state().
> 
> Signed-off-by: Alexander Stein <alexander.stein@...tq-group.com>
> ---
> I noticed this duplicated code while debugging an extcon related issue.
> I do not know if it is allowed in the kernel to assume some behavior in
> EXPORT_SYMBOL* functions, but as the two functions mentioned are in the
> same source file it should be ok.
> In the case it is not okay to assume some behaviour,
> extcon_set_state_sync() is missing a check for !edev, like
> extcon_set_state() does.
> 
>  drivers/extcon/extcon.c | 14 +-------------
>  1 file changed, 1 insertion(+), 13 deletions(-)
> 
> diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
> index e7a9561a826d..a09e704fd0fa 100644
> --- a/drivers/extcon/extcon.c
> +++ b/drivers/extcon/extcon.c
> @@ -576,19 +576,7 @@ EXPORT_SYMBOL_GPL(extcon_set_state);
>   */
>  int extcon_set_state_sync(struct extcon_dev *edev, unsigned int id, bool state)
>  {
> -	int ret, index;
> -	unsigned long flags;
> -
> -	index = find_cable_index_by_id(edev, id);
> -	if (index < 0)
> -		return index;
> -
> -	/* Check whether the external connector's state is changed. */
> -	spin_lock_irqsave(&edev->lock, flags);
> -	ret = is_extcon_changed(edev, index, state);
> -	spin_unlock_irqrestore(&edev->lock, flags);
> -	if (!ret)
> -		return 0;
> +	int ret;
>  
>  	ret = extcon_set_state(edev, id, state);
>  	if (ret < 0)
> 

Applied it. Thanks.

-- 
Best Regards,
Chanwoo Choi
Samsung Electronics