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From:   Ricardo Ribalda <ribalda@chromium.org>
Date:   Tue, 03 Jan 2023 15:36:22 +0100
Subject: [PATCH v3 4/8] media: uvcvideo: Do not return positive errors in
 uvc_query_ctrl()
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Message-Id: <20220920-resend-v4l2-compliance-v3-4-598d33a15815@chromium.org>
References: <20220920-resend-v4l2-compliance-v3-0-598d33a15815@chromium.org>
In-Reply-To: <20220920-resend-v4l2-compliance-v3-0-598d33a15815@chromium.org>
To:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     Hans Verkuil <hverkuil@xs4all.nl>, linux-media@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Ricardo Ribalda <ribalda@chromium.org>,
        Hans Verkuil <hans.verkuil@cisco.com>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>
Precedence: bulk

If the returned size of the query does not match the expected size or it
is zero, return -EPIPE instead of 0 or a positive value.

This will avoid confusing the caller (and ultimately userspace) that
doesn't expect a positive or zero value.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 drivers/media/usb/uvc/uvc_video.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index e56ccde9bd10..feba058fcb06 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -83,7 +83,7 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
 		dev_err(&dev->udev->dev,
 			"Failed to query (%s) UVC control %u on unit %u: %d (exp. %u).\n",
 			uvc_query_name(query), cs, unit, ret, size);
-		return ret;
+		return ret < 0 ? ret : -EPIPE;
 	}
 
 	/* Reuse data[0] to request the error code. */

-- 
2.39.0.314.g84b9a713c41-goog-b4-0.11.0-dev-696ae