serial: arc_uart: simplify flags handling in arc_serial_rx_chars()

* move the declaration of flg (with the initializer) to the loop, so
  there is no need to reset it to TTY_NORMAL by an 'else' branch.
* use TTY_NORMAL as initializer above, not a magic zero constant
* remove the outer 'if' from this construct:
  if (S & (A | B)) {
    if (S & A)
      X;
    if (S & B)
      Y;
  }
* drop unlikely() as I doubt it has any benefits here. If it does,
  provide numbers.

All four make the code easier to read.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Cc: Vineet Gupta <vgupta@kernel.org>
Acked-by: Vineet Gupta <vgupta@kernel.org>
Link: https://lore.kernel.org/r/20230712081811.29004-9-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c
index 4b2512e..8359034 100644 (file)
--- a/drivers/tty/serial/arc_uart.c
+++ b/drivers/tty/serial/arc_uart.c
@@ -195,8 +195,6 @@ static void arc_serial_start_tx(struct uart_port *port)
 
 static void arc_serial_rx_chars(struct uart_port *port, unsigned int status)
 {
-       unsigned int ch, flg = 0;
-
        /*
         * UART has 4 deep RX-FIFO. Driver's recongnition of this fact
         * is very subtle. Here's how ...
@@ -207,24 +205,23 @@ static void arc_serial_rx_chars(struct uart_port *port, unsigned int status)
         * controller, which is indeed the Rx-FIFO.
         */
        do {
+               unsigned int ch, flg = TTY_NORMAL;
+
                /*
                 * This could be an Rx Intr for err (no data),
                 * so check err and clear that Intr first
                 */
-               if (unlikely(status & (RXOERR | RXFERR))) {
-                       if (status & RXOERR) {
-                               port->icount.overrun++;
-                               flg = TTY_OVERRUN;
-                               UART_CLR_STATUS(port, RXOERR);
-                       }
-
-                       if (status & RXFERR) {
-                               port->icount.frame++;
-                               flg = TTY_FRAME;
-                               UART_CLR_STATUS(port, RXFERR);
-                       }
-               } else
-                       flg = TTY_NORMAL;
+               if (status & RXOERR) {
+                       port->icount.overrun++;
+                       flg = TTY_OVERRUN;
+                       UART_CLR_STATUS(port, RXOERR);
+               }
+
+               if (status & RXFERR) {
+                       port->icount.frame++;
+                       flg = TTY_FRAME;
+                       UART_CLR_STATUS(port, RXFERR);
+               }
 
                if (status & RXEMPTY)
                        continue;