media: subdev: Fix use of sd->enabled_streams in call_s_stream()

call_s_stream() uses sd->enabled_streams to track whether streaming has
already been enabled. However,
v4l2_subdev_enable/disable_streams_fallback(), which was the original
user of this field, already uses it, and
v4l2_subdev_enable/disable_streams_fallback() will call call_s_stream().

This leads to a conflict as both functions set the field. Afaics, both
functions set the field to the same value, so it won't cause a runtime
bug, but it's still wrong and if we, e.g., change how
v4l2_subdev_enable/disable_streams_fallback() operates we might easily
cause bugs.

Fix this by adding a new field, 's_stream_enabled', for
call_s_stream().

Reviewed-by: Umang Jain <[email protected]>
Reviewed-by: Laurent Pinchart <[email protected]>
Tested-by: Umang Jain <[email protected]>
Signed-off-by: Tomi Valkeinen <[email protected]>
Signed-off-by: Sakari Ailus <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>

1 files changed, 2 insertions, 6 deletions

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 09b4122d9ab7..8675ad0688af 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -451,12 +451,8 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
 	 * The .s_stream() operation must never be called to start or stop an
 	 * already started or stopped subdev. Catch offenders but don't return
 	 * an error yet to avoid regressions.
-	 *
-	 * As .s_stream() is mutually exclusive with the .enable_streams() and
-	 * .disable_streams() operation, we can use the enabled_streams field
-	 * to store the subdev streaming state.
 	 */
-	if (WARN_ON(!!sd->enabled_streams == !!enable))
+	if (WARN_ON(sd->s_stream_enabled == !!enable))
 		return 0;
 
 	ret = sd->ops->video->s_stream(sd, enable);
@@ -467,7 +463,7 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
 	}
 
 	if (!ret) {
-		sd->enabled_streams = enable ? BIT(0) : 0;
+		sd->s_stream_enabled = enable;
 
 		if (enable)
 			v4l2_subdev_enable_privacy_led(sd);