linux-kernel - [PATCH v3] crypto: ccp: Use scoped guard for mutex

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Message-ID: <20241203162257.6566-1-mario.limonciello@amd.com>
Date: Tue, 3 Dec 2024 10:22:57 -0600
From: Mario Limonciello <mario.limonciello@....com>
To: Herbert Xu <herbert@...dor.apana.org.au>
CC: Mario Limonciello <mario.limonciello@....com>, Tom Lendacky
	<thomas.lendacky@....com>, John Allen <john.allen@....com>, "open list:AMD
 CRYPTOGRAPHIC COPROCESSOR (CCP) DRIVER - DB..."
	<linux-crypto@...r.kernel.org>, open list <linux-kernel@...r.kernel.org>
Subject: [PATCH v3] crypto: ccp: Use scoped guard for mutex

Use a scoped guard to simplify the cleanup handling.

Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
v3:
 * Fix logic error
---
 drivers/crypto/ccp/dbc.c | 53 +++++++++++++++-------------------------
 1 file changed, 20 insertions(+), 33 deletions(-)

diff --git a/drivers/crypto/ccp/dbc.c b/drivers/crypto/ccp/dbc.c
index 5b105a23f6997..410084a9039c9 100644
--- a/drivers/crypto/ccp/dbc.c
+++ b/drivers/crypto/ccp/dbc.c
@@ -7,6 +7,8 @@
  * Author: Mario Limonciello <mario.limonciello@....com>
  */
 
+#include <linux/mutex.h>
+
 #include "dbc.h"
 
 #define DBC_DEFAULT_TIMEOUT		(10 * MSEC_PER_SEC)
@@ -137,64 +139,49 @@ static long dbc_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return -ENODEV;
 	dbc_dev = psp_master->dbc_data;
 
-	mutex_lock(&dbc_dev->ioctl_mutex);
+	guard(mutex)(&dbc_dev->ioctl_mutex);
 
 	switch (cmd) {
 	case DBCIOCNONCE:
-		if (copy_from_user(dbc_dev->payload, argp, sizeof(struct dbc_user_nonce))) {
-			ret = -EFAULT;
-			goto unlock;
-		}
+		if (copy_from_user(dbc_dev->payload, argp, sizeof(struct dbc_user_nonce)))
+			return -EFAULT;
 
 		ret = send_dbc_nonce(dbc_dev);
 		if (ret)
-			goto unlock;
+			return ret;
 
-		if (copy_to_user(argp, dbc_dev->payload, sizeof(struct dbc_user_nonce))) {
-			ret = -EFAULT;
-			goto unlock;
-		}
+		if (copy_to_user(argp, dbc_dev->payload, sizeof(struct dbc_user_nonce)))
+			return -EFAULT;
 		break;
 	case DBCIOCUID:
-		if (copy_from_user(dbc_dev->payload, argp, sizeof(struct dbc_user_setuid))) {
-			ret = -EFAULT;
-			goto unlock;
-		}
+		if (copy_from_user(dbc_dev->payload, argp, sizeof(struct dbc_user_setuid)))
+			return -EFAULT;
 
 		*dbc_dev->payload_size = dbc_dev->header_size + sizeof(struct dbc_user_setuid);
 		ret = send_dbc_cmd(dbc_dev, PSP_DYNAMIC_BOOST_SET_UID);
 		if (ret)
-			goto unlock;
+			return ret;
 
-		if (copy_to_user(argp, dbc_dev->payload, sizeof(struct dbc_user_setuid))) {
-			ret = -EFAULT;
-			goto unlock;
-		}
+		if (copy_to_user(argp, dbc_dev->payload, sizeof(struct dbc_user_setuid)))
+			return -EFAULT;
 		break;
 	case DBCIOCPARAM:
-		if (copy_from_user(dbc_dev->payload, argp, sizeof(struct dbc_user_param))) {
-			ret = -EFAULT;
-			goto unlock;
-		}
+		if (copy_from_user(dbc_dev->payload, argp, sizeof(struct dbc_user_param)))
+			return -EFAULT;
 
 		*dbc_dev->payload_size = dbc_dev->header_size + sizeof(struct dbc_user_param);
 		ret = send_dbc_parameter(dbc_dev);
 		if (ret)
-			goto unlock;
+			return ret;
 
-		if (copy_to_user(argp, dbc_dev->payload, sizeof(struct dbc_user_param)))  {
-			ret = -EFAULT;
-			goto unlock;
-		}
+		if (copy_to_user(argp, dbc_dev->payload, sizeof(struct dbc_user_param)))
+			return -EFAULT;
 		break;
 	default:
-		ret = -EINVAL;
-
+		return -EINVAL;
 	}
-unlock:
-	mutex_unlock(&dbc_dev->ioctl_mutex);
 
-	return ret;
+	return 0;
 }
 
 static const struct file_operations dbc_fops = {

base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37
-- 
2.43.0