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From:   Dan Vacura <w36195@motorola.com>
To:     linux-usb@vger.kernel.org
Cc:     Daniel Scally <dan.scally@ideasonboard.com>,
        Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
        Jeff Vanhoof <qjv001@motorola.com>, stable@vger.kernel.org,
        Dan Vacura <w36195@motorola.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Felipe Balbi <balbi@kernel.org>,
        Paul Elder <paul.elder@ideasonboard.com>,
        Michael Grzeschik <m.grzeschik@pengutronix.de>,
        linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org
Subject: [PATCH v4 4/6] usb: gadget: uvc: fix sg handling during video encode
Date:   Tue, 18 Oct 2022 16:50:40 -0500
Message-Id: <20221018215044.765044-5-w36195@motorola.com>
In-Reply-To: <20221018215044.765044-1-w36195@motorola.com>
References: <20221018215044.765044-1-w36195@motorola.com>
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From: Jeff Vanhoof <qjv001@motorola.com>

In uvc_video_encode_isoc_sg, the uvc_request's sg list is
incorrectly being populated leading to corrupt video being
received by the remote end. When building the sg list the
usage of buf->sg's 'dma_length' field is not correct and
instead its 'length' field should be used.

Fixes: e81e7f9a0eb9 ("usb: gadget: uvc: add scatter gather support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Jeff Vanhoof <qjv001@motorola.com>
Signed-off-by: Dan Vacura <w36195@motorola.com>
---
V1 -> V3:
- no change, new patch in series
V3 -> V4:
- no change

 drivers/usb/gadget/function/uvc_video.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index 5993e083819c..dd1c6b2ca7c6 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -157,10 +157,10 @@ uvc_video_encode_isoc_sg(struct usb_request *req, struct uvc_video *video,
 	sg = sg_next(sg);
 
 	for_each_sg(sg, iter, ureq->sgt.nents - 1, i) {
-		if (!len || !buf->sg || !sg_dma_len(buf->sg))
+		if (!len || !buf->sg || !buf->sg->length)
 			break;
 
-		sg_left = sg_dma_len(buf->sg) - buf->offset;
+		sg_left = buf->sg->length - buf->offset;
 		part = min_t(unsigned int, len, sg_left);
 
 		sg_set_page(iter, sg_page(buf->sg), part, buf->offset);
-- 
2.34.1