serial: core: don't check port twice in a row

There is no need to check port for NULL in uart_port_deref() since we call it
only when port is defined.

There are few places that violate this. Fix them here as well.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 11 insertions, 6 deletions

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index f2303f390345..d0847375ea64 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -73,7 +73,7 @@ static inline struct uart_port *uart_port_ref(struct uart_state *state)
 
 static inline void uart_port_deref(struct uart_port *uport)
 {
-        if (uport && atomic_dec_and_test(&uport->state->refcount))
+        if (atomic_dec_and_test(&uport->state->refcount))
                 wake_up(&uport->state->remove_wait);
 }
 
@@ -88,9 +88,10 @@ static inline void uart_port_deref(struct uart_port *uport)
 #define uart_port_unlock(uport, flags)                                  \
         ({                                                              \
                 struct uart_port *__uport = uport;                      \
-                if (__uport)                                            \
+                if (__uport) {                                          \
                         spin_unlock_irqrestore(&__uport->lock, flags);  \
-                uart_port_deref(__uport);                               \
+                        uart_port_deref(__uport);                       \
+                }                                                       \
         })
 
 static inline struct uart_port *uart_port_check(struct uart_state *state)
@@ -1515,7 +1516,10 @@ static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
         unsigned long char_time, expire;
 
         port = uart_port_ref(state);
-        if (!port || port->type == PORT_UNKNOWN || port->fifosize == 0) {
+        if (!port)
+                return;
+
+        if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
                 uart_port_deref(port);
                 return;
         }
@@ -2365,9 +2369,10 @@ static int uart_poll_get_char(struct tty_driver *driver, int line)
 
         if (state) {
                 port = uart_port_ref(state);
-                if (port)
+                if (port) {
                         ret = port->ops->poll_get_char(port);
-                uart_port_deref(port);
+                        uart_port_deref(port);
+                }
         }
         return ret;
 }