linux-kernel - [PATCH v4 1/2] media: uvcvideo: Refactor streamon/streamoff

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Message-Id: <20220920-resend-powersave-v4-1-47484ae40761@chromium.org>
Date:   Fri, 02 Dec 2022 18:19:31 +0100
From:   Ricardo Ribalda <ribalda@...omium.org>
To:     Mauro Carvalho Chehab <mchehab@...nel.org>
Cc:     linux-media@...r.kernel.org, Yunke Cao <yunkec@...omium.org>,
        Max Staudt <mstaudt@...omium.org>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Tomasz Figa <tfiga@...omium.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Sergey Senozhatsky <senozhatsky@...omium.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Ricardo Ribalda <ribalda@...omium.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4 1/2] media: uvcvideo: Refactor streamon/streamoff

Add a new variable to handle the streaming state and handle the
streamoff errors, that were not handled before.

Suggested-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Reviewed-by: Max Staudt <mstaudt@...omium.org>
Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
---
 drivers/media/usb/uvc/uvc_v4l2.c | 19 ++++++++++++++++---
 drivers/media/usb/uvc/uvcvideo.h |  1 +
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index f4d4c33b6dfb..1389a87b8ae1 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -840,13 +840,19 @@ static int uvc_ioctl_streamon(struct file *file, void *fh,
 {
 	struct uvc_fh *handle = fh;
 	struct uvc_streaming *stream = handle->stream;
-	int ret;
+	int ret = -EBUSY;
 
 	if (!uvc_has_privileges(handle))
 		return -EBUSY;
 
 	mutex_lock(&stream->mutex);
+
+	if (handle->is_streaming)
+		goto unlock;
 	ret = uvc_queue_streamon(&stream->queue, type);
+	handle->is_streaming = !ret;
+
+unlock:
 	mutex_unlock(&stream->mutex);
 
 	return ret;
@@ -857,15 +863,22 @@ static int uvc_ioctl_streamoff(struct file *file, void *fh,
 {
 	struct uvc_fh *handle = fh;
 	struct uvc_streaming *stream = handle->stream;
+	int ret = 0;
 
 	if (!uvc_has_privileges(handle))
 		return -EBUSY;
 
 	mutex_lock(&stream->mutex);
-	uvc_queue_streamoff(&stream->queue, type);
+
+	if (!handle->is_streaming)
+		goto unlock;
+	ret = uvc_queue_streamoff(&stream->queue, type);
+	handle->is_streaming = !!ret;
+
+unlock:
 	mutex_unlock(&stream->mutex);
 
-	return 0;
+	return ret;
 }
 
 static int uvc_ioctl_enum_input(struct file *file, void *fh,
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index df93db259312..45310f55475f 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -581,6 +581,7 @@ enum uvc_handle_state {
 
 struct uvc_fh {
 	struct v4l2_fh vfh;
+	bool is_streaming;
 	struct uvc_video_chain *chain;
 	struct uvc_streaming *stream;
 	enum uvc_handle_state state;

-- 
2.39.0.rc0.267.gcb52ba06e7-goog-b4-0.11.0-dev-696ae