linux-kernel - Re: [PATCH 1/8] media: allegro: use 'time_left' variable with wait_for_completion

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Message-ID: <ZmqwQV6Qm1kqoM8t@pengutronix.de>
Date: Thu, 13 Jun 2024 10:39:29 +0200
From: Michael Tretter <m.tretter@...gutronix.de>
To: Wolfram Sang <wsa+renesas@...g-engineering.com>
Cc: linux-kernel@...r.kernel.org,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	linux-media@...r.kernel.org
Subject: Re: [PATCH 1/8] media: allegro: use 'time_left' variable with
 wait_for_completion_timeout()

Hi Wolfram,

On Mon, 03 Jun 2024 11:28:32 +0200, Wolfram Sang wrote:
> There is a confusing pattern in the kernel to use a variable named 'timeout' to
> store the result of wait_for_completion_timeout() causing patterns like:
> 
> 	timeout = wait_for_completion_timeout(...)
> 	if (!timeout) return -ETIMEDOUT;
> 
> with all kinds of permutations. Use 'time_left' as a variable to make the code
> self explaining.

Thanks for the patch.

There is another instance of wait_for_completion_timeout() in the
driver, which uses tmo instead of timeout. Maybe this patch should
change that, too.

Michael

> 
> Signed-off-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
> ---
>  .../media/platform/allegro-dvt/allegro-core.c    | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/media/platform/allegro-dvt/allegro-core.c b/drivers/media/platform/allegro-dvt/allegro-core.c
> index da61f9beb6b4..4016aef5fdb9 100644
> --- a/drivers/media/platform/allegro-dvt/allegro-core.c
> +++ b/drivers/media/platform/allegro-dvt/allegro-core.c
> @@ -2481,14 +2481,14 @@ static void allegro_mcu_interrupt(struct allegro_dev *dev)
>  static void allegro_destroy_channel(struct allegro_channel *channel)
>  {
>  	struct allegro_dev *dev = channel->dev;
> -	unsigned long timeout;
> +	unsigned long time_left;
>  
>  	if (channel_exists(channel)) {
>  		reinit_completion(&channel->completion);
>  		allegro_mcu_send_destroy_channel(dev, channel);
> -		timeout = wait_for_completion_timeout(&channel->completion,
> -						      msecs_to_jiffies(5000));
> -		if (timeout == 0)
> +		time_left = wait_for_completion_timeout(&channel->completion,
> +							msecs_to_jiffies(5000));
> +		if (time_left == 0)
>  			v4l2_warn(&dev->v4l2_dev,
>  				  "channel %d: timeout while destroying\n",
>  				  channel->mcu_channel_id);
> @@ -2544,7 +2544,7 @@ static void allegro_destroy_channel(struct allegro_channel *channel)
>  static int allegro_create_channel(struct allegro_channel *channel)
>  {
>  	struct allegro_dev *dev = channel->dev;
> -	unsigned long timeout;
> +	unsigned long time_left;
>  
>  	if (channel_exists(channel)) {
>  		v4l2_warn(&dev->v4l2_dev,
> @@ -2595,9 +2595,9 @@ static int allegro_create_channel(struct allegro_channel *channel)
>  
>  	reinit_completion(&channel->completion);
>  	allegro_mcu_send_create_channel(dev, channel);
> -	timeout = wait_for_completion_timeout(&channel->completion,
> -					      msecs_to_jiffies(5000));
> -	if (timeout == 0)
> +	time_left = wait_for_completion_timeout(&channel->completion,
> +						msecs_to_jiffies(5000));
> +	if (time_left == 0)
>  		channel->error = -ETIMEDOUT;
>  	if (channel->error)
>  		goto err;
> -- 
> 2.43.0
> 
>