tty: Drop duplicate NULL check in TTY port functions

The free_page(addr), which becomes free_pages(addr, 0) checks addr against 0.
No need to repeat this check in the callers, i.e.  tty_port_free_xmit_buf()
and tty_port_destructor().

Note, INIT_KFIFO() is safe without that check, because it operates on
a separate member and doesn't rely on the FIFO itself to be allocated.

Acked-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220204153253.11006-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 4282895..880608a 100644 (file)
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -240,11 +240,9 @@ EXPORT_SYMBOL(tty_port_alloc_xmit_buf);
 void tty_port_free_xmit_buf(struct tty_port *port)
 {
        mutex_lock(&port->buf_mutex);
-       if (port->xmit_buf != NULL) {
-               free_page((unsigned long)port->xmit_buf);
-               port->xmit_buf = NULL;
-               INIT_KFIFO(port->xmit_fifo);
-       }
+       free_page((unsigned long)port->xmit_buf);
+       port->xmit_buf = NULL;
+       INIT_KFIFO(port->xmit_fifo);
        mutex_unlock(&port->buf_mutex);
 }
 EXPORT_SYMBOL(tty_port_free_xmit_buf);
@@ -271,8 +269,7 @@ static void tty_port_destructor(struct kref *kref)
        /* check if last port ref was dropped before tty release */
        if (WARN_ON(port->itty))
                return;
-       if (port->xmit_buf)
-               free_page((unsigned long)port->xmit_buf);
+       free_page((unsigned long)port->xmit_buf);
        tty_port_destroy(port);
        if (port->ops && port->ops->destruct)
                port->ops->destruct(port);