linux-kernel - [PATCH 01/13] tty: simplify tty_dev_name_to

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Message-ID: <20240805102046.307511-2-jirislaby@kernel.org>
Date: Mon,  5 Aug 2024 12:20:34 +0200
From: "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
To: gregkh@...uxfoundation.org
Cc: linux-serial@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	"Jiri Slaby (SUSE)" <jirislaby@...nel.org>
Subject: [PATCH 01/13] tty: simplify tty_dev_name_to_number() using guard(mutex)

In tty_dev_name_to_number(), a guard can help to make the code easier to
follow. Especially how 0 is returned in the successful case. So use a
guard there.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
---
 drivers/tty/tty_io.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index bc9aebcb873f..267682bcfea0 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -350,22 +350,19 @@ int tty_dev_name_to_number(const char *name, dev_t *number)
 		return ret;
 
 	prefix_length = str - name;
-	mutex_lock(&tty_mutex);
+
+	guard(mutex)(&tty_mutex);
 
 	list_for_each_entry(p, &tty_drivers, tty_drivers)
 		if (prefix_length == strlen(p->name) && strncmp(name,
 					p->name, prefix_length) == 0) {
 			if (index < p->num) {
 				*number = MKDEV(p->major, p->minor_start + index);
-				goto out;
+				return 0;
 			}
 		}
 
-	/* if here then driver wasn't found */
-	ret = -ENODEV;
-out:
-	mutex_unlock(&tty_mutex);
-	return ret;
+	return -ENODEV;
 }
 EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
 
-- 
2.46.0