linux-kernel - [PATCH v3 08/31] media: staging: media: imx6-mipi-csi2: use guard() to simplify code

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Message-Id: <20250821-95_cam-v3-8-c9286fbb34b9@nxp.com>
Date: Thu, 21 Aug 2025 16:15:43 -0400
From: Frank Li <Frank.Li@....com>
To: Rui Miguel Silva <rmfrfs@...il.com>, 
 Laurent Pinchart <laurent.pinchart@...asonboard.com>, 
 Martin Kepplinger <martink@...teo.de>, Purism Kernel Team <kernel@...i.sm>, 
 Mauro Carvalho Chehab <mchehab@...nel.org>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, 
 Eugen Hristev <eugen.hristev@...aro.org>, Shawn Guo <shawnguo@...nel.org>, 
 Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, Peng Fan <peng.fan@....com>, 
 Alice Yuan <alice.yuan@....com>, Vinod Koul <vkoul@...nel.org>, 
 Kishon Vijay Abraham I <kishon@...nel.org>, 
 Philipp Zabel <p.zabel@...gutronix.de>, 
 Steve Longerbeam <slongerbeam@...il.com>, 
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: linux-media@...r.kernel.org, devicetree@...r.kernel.org, 
 linux-kernel@...r.kernel.org, imx@...ts.linux.dev, 
 linux-arm-kernel@...ts.infradead.org, linux-phy@...ts.infradead.org, 
 linux-staging@...ts.linux.dev, Frank Li <Frank.Li@....com>
Subject: [PATCH v3 08/31] media: staging: media: imx6-mipi-csi2: use
 guard() to simplify code

Use guard() to simplify mutex locking. No functional change.

Signed-off-by: Frank Li <Frank.Li@....com>
---
 drivers/staging/media/imx/imx6-mipi-csi2.c | 54 +++++++++++-------------------
 1 file changed, 19 insertions(+), 35 deletions(-)

diff --git a/drivers/staging/media/imx/imx6-mipi-csi2.c b/drivers/staging/media/imx/imx6-mipi-csi2.c
index f8d0b3b8b250774af51f2aba731e639131aceff9..54e9491d3428686288a5bc9bb58a5a0a25aca696 100644
--- a/drivers/staging/media/imx/imx6-mipi-csi2.c
+++ b/drivers/staging/media/imx/imx6-mipi-csi2.c
@@ -413,21 +413,17 @@ static int csi2_s_stream(struct v4l2_subdev *sd, int enable)
 	struct csi2_dev *csi2 = sd_to_dev(sd);
 	int i, ret = 0;
 
-	mutex_lock(&csi2->lock);
+	guard(mutex)(&csi2->lock);
 
-	if (!csi2->src_sd) {
-		ret = -EPIPE;
-		goto out;
-	}
+	if (!csi2->src_sd)
+		return -EPIPE;
 
 	for (i = 0; i < CSI2_NUM_SRC_PADS; i++) {
 		if (csi2->sink_linked[i])
 			break;
 	}
-	if (i >= CSI2_NUM_SRC_PADS) {
-		ret = -EPIPE;
-		goto out;
-	}
+	if (i >= CSI2_NUM_SRC_PADS)
+		return -EPIPE;
 
 	/*
 	 * enable/disable streaming only if stream_count is
@@ -442,14 +438,12 @@ static int csi2_s_stream(struct v4l2_subdev *sd, int enable)
 	else
 		csi2_stop(csi2);
 	if (ret)
-		goto out;
+		return ret;
 
 update_count:
 	csi2->stream_count += enable ? 1 : -1;
 	if (csi2->stream_count < 0)
 		csi2->stream_count = 0;
-out:
-	mutex_unlock(&csi2->lock);
 	return ret;
 }
 
@@ -467,32 +461,28 @@ static int csi2_link_setup(struct media_entity *entity,
 
 	remote_sd = media_entity_to_v4l2_subdev(remote->entity);
 
-	mutex_lock(&csi2->lock);
+	guard(mutex)(&csi2->lock);
 
 	if (local->flags & MEDIA_PAD_FL_SOURCE) {
 		if (flags & MEDIA_LNK_FL_ENABLED) {
-			if (csi2->sink_linked[local->index - 1]) {
-				ret = -EBUSY;
-				goto out;
-			}
+			if (csi2->sink_linked[local->index - 1])
+				return -EBUSY;
+
 			csi2->sink_linked[local->index - 1] = true;
 		} else {
 			csi2->sink_linked[local->index - 1] = false;
 		}
 	} else {
 		if (flags & MEDIA_LNK_FL_ENABLED) {
-			if (csi2->src_sd) {
-				ret = -EBUSY;
-				goto out;
-			}
+			if (csi2->src_sd)
+				return -EBUSY;
+
 			csi2->src_sd = remote_sd;
 		} else {
 			csi2->src_sd = NULL;
 		}
 	}
 
-out:
-	mutex_unlock(&csi2->lock);
 	return ret;
 }
 
@@ -513,14 +503,12 @@ static int csi2_get_fmt(struct v4l2_subdev *sd,
 	struct csi2_dev *csi2 = sd_to_dev(sd);
 	struct v4l2_mbus_framefmt *fmt;
 
-	mutex_lock(&csi2->lock);
+	guard(mutex)(&csi2->lock);
 
 	fmt = __csi2_get_fmt(csi2, sd_state, sdformat->pad, sdformat->which);
 
 	sdformat->format = *fmt;
 
-	mutex_unlock(&csi2->lock);
-
 	return 0;
 }
 
@@ -530,17 +518,14 @@ static int csi2_set_fmt(struct v4l2_subdev *sd,
 {
 	struct csi2_dev *csi2 = sd_to_dev(sd);
 	struct v4l2_mbus_framefmt *fmt;
-	int ret = 0;
 
 	if (sdformat->pad >= CSI2_NUM_PADS)
 		return -EINVAL;
 
-	mutex_lock(&csi2->lock);
+	guard(mutex)(&csi2->lock);
 
-	if (csi2->stream_count > 0) {
-		ret = -EBUSY;
-		goto out;
-	}
+	if (csi2->stream_count > 0)
+		return -EBUSY;
 
 	/* Output pads mirror active input pad, no limits on input pads */
 	if (sdformat->pad != CSI2_SINK_PAD)
@@ -549,9 +534,8 @@ static int csi2_set_fmt(struct v4l2_subdev *sd,
 	fmt = __csi2_get_fmt(csi2, sd_state, sdformat->pad, sdformat->which);
 
 	*fmt = sdformat->format;
-out:
-	mutex_unlock(&csi2->lock);
-	return ret;
+
+	return 0;
 }
 
 static int csi2_registered(struct v4l2_subdev *sd)

-- 
2.34.1