[PATCH] tty: serial: return appropriate error on failure

when a user with CAP_SYS_ADMIN disabled calls ioctl (TIOCSSERIAL),
uart_set_info() returns 0 instead of -EPERM and the user remains unware
about what went wrong. Fix this.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215205

Signed-off-by: Vihas Mak <redacted>
---
 drivers/tty/serial/serial_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 61e3dd022..c204bdecc 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c

@@ -960,7 +960,7 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 		uport->fifosize = new_info->xmit_fifo_size;
 
  check_and_exit:
-	retval = 0;
+	retval = retval < 0 ? retval : 0;
 	if (uport->type == PORT_UNKNOWN)
 		goto exit;
 	if (tty_port_initialized(port)) {

-- 
2.30.2