linux-kernel - [PATCH 11/11] media: xilinx: simplify get fourcc logic

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Date:   Wed, 16 Jun 2021 14:28:37 +0200
From:   Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
To:     unlisted-recipients:; (no To-header on input)
Cc:     linuxarm@...wei.com, mauro.chehab@...wei.com,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        Hyun Kwon <hyun.kwon@...inx.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Michal Simek <michal.simek@...inx.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-media@...r.kernel.org
Subject: [PATCH 11/11] media: xilinx: simplify get fourcc logic

Right now, there are two calls for xvip_get_format_by_fourcc().
If the first one fails, it is called again in order to pick
the first available format: V4L2_PIX_FMT_YUYV.

This ends by producing a smatch warnings:
	drivers/media/platform/xilinx/xilinx-dma.c:555 __xvip_dma_try_format() error: 'info' dereferencing possible ERR_PTR()
	drivers/media/platform/xilinx/xilinx-dma.c: drivers/media/platform/xilinx/xilinx-dma.c:664 xvip_dma_init() error: 'dma->fmtinfo' dereferencing possible ERR_PTR()

as it is hard for an static analyzer to ensure that calling
xvip_get_format_by_fourcc(XVIP_DMA_DEF_FORMAT) won't return an
error.

So, better to optimize the logic, ensuring that the function
will never return an error.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
---
 drivers/media/platform/xilinx/xilinx-dma.c | 5 +----
 drivers/media/platform/xilinx/xilinx-vip.c | 6 +++---
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/media/platform/xilinx/xilinx-dma.c b/drivers/media/platform/xilinx/xilinx-dma.c
index 2a56201cb853..338c3661d809 100644
--- a/drivers/media/platform/xilinx/xilinx-dma.c
+++ b/drivers/media/platform/xilinx/xilinx-dma.c
@@ -26,7 +26,6 @@
 #include "xilinx-vip.h"
 #include "xilinx-vipp.h"
 
-#define XVIP_DMA_DEF_FORMAT		V4L2_PIX_FMT_YUYV
 #define XVIP_DMA_DEF_WIDTH		1920
 #define XVIP_DMA_DEF_HEIGHT		1080
 
@@ -549,8 +548,6 @@ __xvip_dma_try_format(struct xvip_dma *dma, struct v4l2_pix_format *pix,
 	 * requested format isn't supported.
 	 */
 	info = xvip_get_format_by_fourcc(pix->pixelformat);
-	if (IS_ERR(info))
-		info = xvip_get_format_by_fourcc(XVIP_DMA_DEF_FORMAT);
 
 	pix->pixelformat = info->fourcc;
 	pix->field = V4L2_FIELD_NONE;
@@ -660,7 +657,7 @@ int xvip_dma_init(struct xvip_composite_device *xdev, struct xvip_dma *dma,
 	INIT_LIST_HEAD(&dma->queued_bufs);
 	spin_lock_init(&dma->queued_lock);
 
-	dma->fmtinfo = xvip_get_format_by_fourcc(XVIP_DMA_DEF_FORMAT);
+	dma->fmtinfo = xvip_get_format_by_fourcc(V4L2_PIX_FMT_YUYV);
 	dma->format.pixelformat = dma->fmtinfo->fourcc;
 	dma->format.colorspace = V4L2_COLORSPACE_SRGB;
 	dma->format.field = V4L2_FIELD_NONE;
diff --git a/drivers/media/platform/xilinx/xilinx-vip.c b/drivers/media/platform/xilinx/xilinx-vip.c
index 6ad61b08a31a..a4eb57683411 100644
--- a/drivers/media/platform/xilinx/xilinx-vip.c
+++ b/drivers/media/platform/xilinx/xilinx-vip.c
@@ -70,8 +70,8 @@ EXPORT_SYMBOL_GPL(xvip_get_format_by_code);
  * @fourcc: the format 4CC
  *
  * Return: a pointer to the format information structure corresponding to the
- * given V4L2 format @fourcc, or ERR_PTR if no corresponding format can be
- * found.
+ * given V4L2 format @fourcc. If not found, return a pointer to the first
+ * available format (V4L2_PIX_FMT_YUYV).
  */
 const struct xvip_video_format *xvip_get_format_by_fourcc(u32 fourcc)
 {
@@ -84,7 +84,7 @@ const struct xvip_video_format *xvip_get_format_by_fourcc(u32 fourcc)
 			return format;
 	}
 
-	return ERR_PTR(-EINVAL);
+	return &xvip_video_formats[0];
 }
 EXPORT_SYMBOL_GPL(xvip_get_format_by_fourcc);
 
-- 
2.31.1