linux-kernel - [PATCH 10/33] serial: 8250: invert conditions in RSA functions

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Message-ID: <20250611100319.186924-11-jirislaby@kernel.org>
Date: Wed, 11 Jun 2025 12:02:56 +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>
Subject: [PATCH 10/33] serial: 8250: invert conditions in RSA functions

The code can short-return in case something does not hold. So invert the
conditions and return in those cases immediately. This makes the code
flow more natural and less nested.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
---
 drivers/tty/serial/8250/8250_port.c | 59 +++++++++++++++++------------
 1 file changed, 34 insertions(+), 25 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 233316a88df2..e7652d62ab2f 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -743,15 +743,16 @@ static int __enable_rsa(struct uart_8250_port *up)
  */
 static void enable_rsa(struct uart_8250_port *up)
 {
-	if (up->port.type == PORT_RSA) {
-		if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) {
-			uart_port_lock_irq(&up->port);
-			__enable_rsa(up);
-			uart_port_unlock_irq(&up->port);
-		}
-		if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)
-			serial_out(up, UART_RSA_FRR, 0);
+	if (up->port.type != PORT_RSA)
+		return;
+
+	if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) {
+		uart_port_lock_irq(&up->port);
+		__enable_rsa(up);
+		uart_port_unlock_irq(&up->port);
 	}
+	if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)
+		serial_out(up, UART_RSA_FRR, 0);
 }
 
 /*
@@ -764,37 +765,45 @@ static void disable_rsa(struct uart_8250_port *up)
 	unsigned char mode;
 	int result;
 
-	if (up->port.type == PORT_RSA &&
-	    up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) {
-		uart_port_lock_irq(&up->port);
+	if (up->port.type != PORT_RSA)
+		return;
 
-		mode = serial_in(up, UART_RSA_MSR);
-		result = !(mode & UART_RSA_MSR_FIFO);
+	if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16)
+		return;
 
-		if (!result) {
-			serial_out(up, UART_RSA_MSR, mode & ~UART_RSA_MSR_FIFO);
-			mode = serial_in(up, UART_RSA_MSR);
-			result = !(mode & UART_RSA_MSR_FIFO);
-		}
+	uart_port_lock_irq(&up->port);
+	mode = serial_in(up, UART_RSA_MSR);
+	result = !(mode & UART_RSA_MSR_FIFO);
 
-		if (result)
-			up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;
-		uart_port_unlock_irq(&up->port);
+	if (!result) {
+		serial_out(up, UART_RSA_MSR, mode & ~UART_RSA_MSR_FIFO);
+		mode = serial_in(up, UART_RSA_MSR);
+		result = !(mode & UART_RSA_MSR_FIFO);
 	}
+
+	if (result)
+		up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;
+	uart_port_unlock_irq(&up->port);
 }
 
 static void rsa_autoconfig(struct uart_8250_port *up)
 {
 	/* Only probe for RSA ports if we got the region. */
-	if (up->port.type == PORT_16550A && up->probe & UART_PROBE_RSA &&
-	    __enable_rsa(up))
+	if (up->port.type != PORT_16550A)
+		return;
+	if (!(up->probe & UART_PROBE_RSA))
+		return;
+
+	if (__enable_rsa(up))
 		up->port.type = PORT_RSA;
 }
 
 static void rsa_reset(struct uart_8250_port *up)
 {
-	if (up->port.type == PORT_RSA)
-		serial_out(up, UART_RSA_FRR, 0);
+	if (up->port.type != PORT_RSA)
+		return;
+
+	serial_out(up, UART_RSA_FRR, 0);
 }
 #else
 static inline void enable_rsa(struct uart_8250_port *up) {}
-- 
2.49.0