linux-kernel - [PATCH v2 1/3] media: uvcvideo: Return the number of processed controls

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250224-uvc-data-backup-v2-1-de993ed9823b@chromium.org>
Date: Mon, 24 Feb 2025 10:34:53 +0000
From: Ricardo Ribalda <ribalda@...omium.org>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>, 
 Hans de Goede <hdegoede@...hat.com>, 
 Mauro Carvalho Chehab <mchehab@...nel.org>
Cc: linux-media@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Ricardo Ribalda <ribalda@...omium.org>, stable@...nel.org
Subject: [PATCH v2 1/3] media: uvcvideo: Return the number of processed
 controls

If we let know our callers that we have not done anything, they will be
able to optimize their decisions.

Cc: stable@...nel.org
Fixes: b4012002f3a3 ("[media] uvcvideo: Add support for control events")
Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
---
 drivers/media/usb/uvc/uvc_ctrl.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index 4e58476d305e..f2484f6d21c1 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1846,12 +1846,17 @@ int uvc_ctrl_begin(struct uvc_video_chain *chain)
 	return mutex_lock_interruptible(&chain->ctrl_mutex) ? -ERESTARTSYS : 0;
 }
 
+/*
+ * Returns the number of uvc controls that have been correctly set, or a
+ * negative number if there has been an error.
+ */
 static int uvc_ctrl_commit_entity(struct uvc_device *dev,
 				  struct uvc_fh *handle,
 				  struct uvc_entity *entity,
 				  int rollback,
 				  struct uvc_control **err_ctrl)
 {
+	unsigned int processed_ctrls = 0;
 	struct uvc_control *ctrl;
 	unsigned int i;
 	int ret;
@@ -1886,6 +1891,9 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev,
 		else
 			ret = 0;
 
+		if (!ret)
+			processed_ctrls++;
+
 		if (rollback || ret < 0)
 			memcpy(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT),
 			       uvc_ctrl_data(ctrl, UVC_CTRL_DATA_BACKUP),
@@ -1904,7 +1912,7 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev,
 			uvc_ctrl_set_handle(handle, ctrl, handle);
 	}
 
-	return 0;
+	return processed_ctrls;
 }
 
 static int uvc_ctrl_find_ctrl_idx(struct uvc_entity *entity,
@@ -1951,6 +1959,7 @@ int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback,
 
 	if (!rollback)
 		uvc_ctrl_send_events(handle, ctrls->controls, ctrls->count);
+	ret = 0;
 done:
 	mutex_unlock(&chain->ctrl_mutex);
 	return ret;

-- 
2.48.1.601.g30ceb7b040-goog