linux-kernel - [PATCH 08/10] serial: arc_uart: simplify flags handling in arc_serial_rx

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Message-ID: <20230712081811.29004-9-jirislaby@kernel.org>
Date:   Wed, 12 Jul 2023 10:18:09 +0200
From:   "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
To:     gregkh@...uxfoundation.org
Cc:     linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Jiri Slaby (SUSE)" <jirislaby@...nel.org>,
        Vineet Gupta <vgupta@...nel.org>
Subject: [PATCH 08/10] 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@...nel.org>
Cc: Vineet Gupta <vgupta@...nel.org>
---
 drivers/tty/serial/arc_uart.c | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c
index 4b2512eef577..835903488acb 100644
--- 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;
-- 
2.41.0