linux-kernel - [PATCH 09/10] serial: serial_core: simplify uart

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251119100140.830761-10-jirislaby@kernel.org>
Date: Wed, 19 Nov 2025 11:01:39 +0100
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 09/10] serial: serial_core: simplify uart_ioctl() returns

Neither uart_do_autoconfig(), nor uart_wait_modem_status() can return
-ENOIOCTLCMD. The ENOIOCTLCMD checks are there to check if 'cmd' matched
against TIOCSERCONFIG, and TIOCMIWAIT respectively. (With 0 or error in
'ret', it does not matter.)

Therefore, the code can simply return from the TIOCSERCONFIG and
TIOCMIWAIT spots immediately.

To be more explicit, use 'if' instead of switch-case for those single
values.

And return without jumping to the 'out' label -- it can be removed too.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
---
 drivers/tty/serial/serial_core.c | 35 ++++++++------------------------
 1 file changed, 9 insertions(+), 26 deletions(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 4757293ece8c..74018fb8a4e7 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1560,37 +1560,20 @@ uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
 	void __user *uarg = (void __user *)arg;
 	int ret = -ENOIOCTLCMD;
 
-
-	/*
-	 * These ioctls don't rely on the hardware to be present.
-	 */
-	switch (cmd) {
-	case TIOCSERCONFIG:
+	/* This ioctl doesn't rely on the hardware to be present. */
+	if (cmd == TIOCSERCONFIG) {
 		down_write(&tty->termios_rwsem);
 		ret = uart_do_autoconfig(tty, state);
 		up_write(&tty->termios_rwsem);
-		break;
-	}
-
-	if (ret != -ENOIOCTLCMD)
-		goto out;
-
-	if (tty_io_error(tty)) {
-		ret = -EIO;
-		goto out;
+		return ret;
 	}
 
-	/*
-	 * The following should only be used when hardware is present.
-	 */
-	switch (cmd) {
-	case TIOCMIWAIT:
-		ret = uart_wait_modem_status(state, arg);
-		break;
-	}
+	if (tty_io_error(tty))
+		return -EIO;
 
-	if (ret != -ENOIOCTLCMD)
-		goto out;
+	/* This should only be used when the hardware is present. */
+	if (cmd == TIOCMIWAIT)
+		return uart_wait_modem_status(state, arg);
 
 	/* rs485_config requires more locking than others */
 	if (cmd == TIOCSRS485)
@@ -1638,7 +1621,7 @@ uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
 	mutex_unlock(&port->mutex);
 	if (cmd == TIOCSRS485)
 		up_write(&tty->termios_rwsem);
-out:
+
 	return ret;
 }
 
-- 
2.51.1