linux-kernel - [PATCH] chardev: Switch to guard(mutex)

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Message-Id: <20251215060657.87947-1-chenzhang@kylinos.cn>
Date: Mon, 15 Dec 2025 14:06:57 +0800
From: chen zhang <chenzhang@...inos.cn>
To: viro@...iv.linux.org.uk,
	brauner@...nel.org,
	jack@...e.cz
Cc: linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	chenzhang_0901@....com,
	chen zhang <chenzhang@...inos.cn>
Subject: [PATCH] chardev: Switch to guard(mutex)

Instead of using the 'goto label; mutex_unlock()' pattern use
'guard(mutex)' which will release the mutex when it goes out of scope.

Signed-off-by: chen zhang <chenzhang@...inos.cn>
---
 fs/char_dev.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/fs/char_dev.c b/fs/char_dev.c
index c2ddb998f3c9..ca6037304e19 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -117,14 +117,15 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
 	if (cd == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	mutex_lock(&chrdevs_lock);
+	guard(mutex)(&chrdevs_lock);
 
 	if (major == 0) {
 		ret = find_dynamic_major();
 		if (ret < 0) {
 			pr_err("CHRDEV \"%s\" dynamic allocation region is full\n",
 			       name);
-			goto out;
+			kfree(cd);
+			return ERR_PTR(ret);
 		}
 		major = ret;
 	}
@@ -144,7 +145,8 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
 		if (curr->baseminor >= baseminor + minorct)
 			break;
 
-		goto out;
+		kfree(cd);
+		return ERR_PTR(ret);
 	}
 
 	cd->major = major;
@@ -160,12 +162,7 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
 		prev->next = cd;
 	}
 
-	mutex_unlock(&chrdevs_lock);
 	return cd;
-out:
-	mutex_unlock(&chrdevs_lock);
-	kfree(cd);
-	return ERR_PTR(ret);
 }
 
 static struct char_device_struct *
-- 
2.25.1