linux-kernel - [PATCH v5 2/3] media: uvcvideo: Always use uvc_status

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Message-Id: <20231122-guenter-mini-v5-2-15d8cd8ed74f@chromium.org>
Date:   Wed, 22 Nov 2023 11:45:48 +0000
From:   Ricardo Ribalda <ribalda@...omium.org>
To:     Mauro Carvalho Chehab <mchehab@...nel.org>
Cc:     Guenter Roeck <linux@...ck-us.net>,
        Tomasz Figa <tfiga@...omium.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Alan Stern <stern@...land.harvard.edu>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        Sean Paul <seanpaul@...omium.org>,
        Ricardo Ribalda <ribalda@...omium.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>
Subject: [PATCH v5 2/3] media: uvcvideo: Always use uvc_status_stop()

The only thread safe way to stop the status handler is with uvc_status.

Let's remove all the code paths partially stopping uvc_status.

Reviewed-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
---
 drivers/media/usb/uvc/uvc_ctrl.c   | 4 ----
 drivers/media/usb/uvc/uvc_driver.c | 2 +-
 drivers/media/usb/uvc/uvc_status.c | 8 ++++----
 drivers/media/usb/uvc/uvc_v4l2.c   | 2 +-
 drivers/media/usb/uvc/uvcvideo.h   | 2 +-
 5 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index e59a463c2761..8e22a07e3e7b 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -2765,10 +2765,6 @@ void uvc_ctrl_cleanup_device(struct uvc_device *dev)
 	struct uvc_entity *entity;
 	unsigned int i;
 
-	/* Can be uninitialized if we are aborting on probe error. */
-	if (dev->async_ctrl.work.func)
-		cancel_work_sync(&dev->async_ctrl.work);
-
 	/* Free controls and control mappings for all entities. */
 	list_for_each_entry(entity, &dev->entities, list) {
 		for (i = 0; i < entity->ncontrols; ++i) {
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index ded2cb6ce14f..d5dbf2644272 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -2282,7 +2282,7 @@ static int uvc_suspend(struct usb_interface *intf, pm_message_t message)
 	    UVC_SC_VIDEOCONTROL) {
 		mutex_lock(&dev->lock);
 		if (dev->users)
-			uvc_status_stop(dev);
+			uvc_status_stop(dev, true);
 		mutex_unlock(&dev->lock);
 		return 0;
 	}
diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c
index a78a88c710e2..9c5da1244999 100644
--- a/drivers/media/usb/uvc/uvc_status.c
+++ b/drivers/media/usb/uvc/uvc_status.c
@@ -292,7 +292,7 @@ int uvc_status_init(struct uvc_device *dev)
 
 void uvc_status_unregister(struct uvc_device *dev)
 {
-	usb_kill_urb(dev->int_urb);
+	uvc_status_stop(dev, false);
 	uvc_input_unregister(dev);
 }
 
@@ -310,7 +310,7 @@ int uvc_status_start(struct uvc_device *dev, gfp_t flags)
 	return usb_submit_urb(dev->int_urb, flags);
 }
 
-void uvc_status_stop(struct uvc_device *dev)
+void uvc_status_stop(struct uvc_device *dev, bool run_async_work)
 {
 	struct uvc_ctrl_work *w = &dev->async_ctrl;
 
@@ -326,7 +326,7 @@ void uvc_status_stop(struct uvc_device *dev)
 	 * Cancel any pending asynchronous work. If any status event was queued,
 	 * process it synchronously.
 	 */
-	if (cancel_work_sync(&w->work))
+	if (cancel_work_sync(&w->work) && run_async_work)
 		uvc_ctrl_status_event(w->chain, w->ctrl, w->data);
 
 	/* Kill the urb. */
@@ -338,7 +338,7 @@ void uvc_status_stop(struct uvc_device *dev)
 	 * cancelled before returning or it could then race with a future
 	 * uvc_status_start() call.
 	 */
-	if (cancel_work_sync(&w->work))
+	if (cancel_work_sync(&w->work) && run_async_work)
 		uvc_ctrl_status_event(w->chain, w->ctrl, w->data);
 
 	/*
diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index f4988f03640a..f90206263ff4 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -672,7 +672,7 @@ static int uvc_v4l2_release(struct file *file)
 
 	mutex_lock(&stream->dev->lock);
 	if (--stream->dev->users == 0)
-		uvc_status_stop(stream->dev);
+		uvc_status_stop(stream->dev, false);
 	mutex_unlock(&stream->dev->lock);
 
 	usb_autopm_put_interface(stream->dev->intf);
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 6fb0a78b1b00..ba8f8c1f2c83 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -745,7 +745,7 @@ int uvc_status_init(struct uvc_device *dev);
 void uvc_status_unregister(struct uvc_device *dev);
 void uvc_status_cleanup(struct uvc_device *dev);
 int uvc_status_start(struct uvc_device *dev, gfp_t flags);
-void uvc_status_stop(struct uvc_device *dev);
+void uvc_status_stop(struct uvc_device *dev, bool run_async_work);
 
 /* Controls */
 extern const struct uvc_control_mapping uvc_ctrl_power_line_mapping_limited;

-- 
2.43.0.rc1.413.gea7ed67945-goog