[PATCH v5] media: vimc: streamer: if kthread_stop fails, ignore the error

[PATCH v5] media: vimc: streamer: if kthread_stop fails, ignore the error

[Dafna Hirschfeld]

Ignore errors returned from kthread_stop since the
vimc subdevices should still be notified that
streaming stopped so they can release the memory for
the streaming, and also kthread should be set to NULL.
kthread_stop can return -EINTR in case the thread
did not yet run. This can happen if userspace calls
streamon and streamoff right after.

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
---
changes from v4: change dev_warn to dev_dbg, delete and add a empty lines
Changes from v3: change the comment to explain when kthread fails
changes since v2: add a comment explaning why we ignore the error
Changes from v1: undo deletion of an empty line

 drivers/media/platform/vimc/vimc-streamer.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/vimc/vimc-streamer.c b/drivers/media/platform/vimc/vimc-streamer.c
index cd6b55433c9e..9d2b1ff2ba45 100644
--- a/drivers/media/platform/vimc/vimc-streamer.c
+++ b/drivers/media/platform/vimc/vimc-streamer.c
@@ -215,8 +215,14 @@ int vimc_streamer_s_stream(struct vimc_stream *stream,
 			return 0;
 
 		ret = kthread_stop(stream->kthread);
+		/*
+		 * kthread_stop returns -EINTR in cases when streamon was
+		 * immediately followed by streamoff, and the thread didn't had
+		 * a chance to run. Ignore errors to stop the stream in the
+		 * pipeline.
+		 */
 		if (ret)
-			return ret;
+			dev_dbg(ved->dev, "kthread_stop returned '%d'\n", ret);
 
 		stream->kthread = NULL;
 
-- 
2.17.1

Re: [PATCH v5] media: vimc: streamer: if kthread_stop fails, ignore the error

[Helen Koike]

On 1/22/20 7:52 AM, Dafna Hirschfeld wrote:
> Ignore errors returned from kthread_stop since the
> vimc subdevices should still be notified that
> streaming stopped so they can release the memory for
> the streaming, and also kthread should be set to NULL.
> kthread_stop can return -EINTR in case the thread
> did not yet run. This can happen if userspace calls
> streamon and streamoff right after.
> 
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>

Acked-by: Helen Koike <helen.koike@collabora.com>

Thanks
Helen

> ---
> changes from v4: change dev_warn to dev_dbg, delete and add a empty lines
> Changes from v3: change the comment to explain when kthread fails
> changes since v2: add a comment explaning why we ignore the error
> Changes from v1: undo deletion of an empty line
> 
>  drivers/media/platform/vimc/vimc-streamer.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/vimc/vimc-streamer.c b/drivers/media/platform/vimc/vimc-streamer.c
> index cd6b55433c9e..9d2b1ff2ba45 100644
> --- a/drivers/media/platform/vimc/vimc-streamer.c
> +++ b/drivers/media/platform/vimc/vimc-streamer.c
> @@ -215,8 +215,14 @@ int vimc_streamer_s_stream(struct vimc_stream *stream,
>  			return 0;
>  
>  		ret = kthread_stop(stream->kthread);
> +		/*
> +		 * kthread_stop returns -EINTR in cases when streamon was
> +		 * immediately followed by streamoff, and the thread didn't had
> +		 * a chance to run. Ignore errors to stop the stream in the
> +		 * pipeline.
> +		 */
>  		if (ret)
> -			return ret;
> +			dev_dbg(ved->dev, "kthread_stop returned '%d'\n", ret);
>  
>  		stream->kthread = NULL;
>  
>