2024-06-03 09:32:41

by Wolfram Sang

Subject: [PATCH 1/8] media: allegro: use 'time_left' variable with wait_for_completion_timeout()

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.

Signed-off-by: Wolfram Sang <[email protected]>
---
.../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

2024-06-13 08:42:41

by Michael Tretter

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 <[email protected]>
> ---
> .../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
>
>