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From:   Colin King <colin.king@canonical.com>
To:     Mirela Rabulea <mirela.rabulea@nxp.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        linux-media@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc:     kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH][next] media: imx-jpeg: Pass the v4l2_jpeg_header header argument by reference
Date:   Tue, 23 Mar 2021 14:24:21 +0000
Message-Id: <20210323142421.348695-1-colin.king@canonical.com>
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From: Colin Ian King <colin.king@canonical.com>

Currently the header argument is being passed by value, so a copy of 256
byte structure on the stack is potentially occurring. Fix this by passing
by reference to avoid any large stack copies.

Addresses-Coverity: ("Big parameter passed by value")
Fixes: 2db16c6ed72c ("media: imx-jpeg: Add V4L2 driver for i.MX8 JPEG Encoder/Decoder")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/media/platform/imx-jpeg/mxc-jpeg.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/media/platform/imx-jpeg/mxc-jpeg.c b/drivers/media/platform/imx-jpeg/mxc-jpeg.c
index adb1715c75d7..f13a8efc35ad 100644
--- a/drivers/media/platform/imx-jpeg/mxc-jpeg.c
+++ b/drivers/media/platform/imx-jpeg/mxc-jpeg.c
@@ -1114,21 +1114,21 @@ static int mxc_jpeg_valid_comp_id(struct device *dev,
 }
 
 static u32 mxc_jpeg_get_image_format(struct device *dev,
-				     const struct v4l2_jpeg_header header)
+				     const struct v4l2_jpeg_header *header)
 {
 	int i;
 	u32 fourcc = 0;
 
 	for (i = 0; i < MXC_JPEG_NUM_FORMATS; i++)
-		if (mxc_formats[i].subsampling == header.frame.subsampling &&
-		    mxc_formats[i].nc == header.frame.num_components) {
+		if (mxc_formats[i].subsampling == header->frame.subsampling &&
+		    mxc_formats[i].nc == header->frame.num_components) {
 			fourcc = mxc_formats[i].fourcc;
 			break;
 		}
 	if (fourcc == 0) {
 		dev_err(dev, "Could not identify image format nc=%d, subsampling=%d\n",
-			header.frame.num_components,
-			header.frame.subsampling);
+			header->frame.num_components,
+			header->frame.subsampling);
 		return fourcc;
 	}
 	/*
@@ -1137,7 +1137,7 @@ static u32 mxc_jpeg_get_image_format(struct device *dev,
 	 * ITU-T T.872 chapter 6.5.3 APP14 marker segment for colour encoding
 	 */
 	if (fourcc == V4L2_PIX_FMT_YUV24 || fourcc == V4L2_PIX_FMT_RGB24) {
-		if (header.app14_tf == V4L2_JPEG_APP14_TF_CMYK_RGB)
+		if (header->app14_tf == V4L2_JPEG_APP14_TF_CMYK_RGB)
 			fourcc = V4L2_PIX_FMT_RGB24;
 		else
 			fourcc = V4L2_PIX_FMT_YUV24;
@@ -1258,7 +1258,7 @@ static int mxc_jpeg_parse(struct mxc_jpeg_ctx *ctx,
 	if (!mxc_jpeg_valid_comp_id(dev, psof, psos))
 		dev_warn(dev, "JPEG component ids should be 0-3 or 1-4");
 
-	fourcc = mxc_jpeg_get_image_format(dev, header);
+	fourcc = mxc_jpeg_get_image_format(dev, &header);
 	if (fourcc == 0)
 		return -EINVAL;
 
-- 
2.30.2