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@kernel.org>
Link: https://patch.msgid.link/20251119100140.830761-10-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 4757293ece8c65af1f5a73b99e8b9a44fceb5bbb..74018fb8a4e71dfe3a066e8de671c4151fdd4473 100644 (file)
--- 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 @@ out_up:
        mutex_unlock(&port->mutex);
        if (cmd == TIOCSRS485)
                up_write(&tty->termios_rwsem);
-out:
+
        return ret;
 }