linux-kernel - [PATCH 6/6] serial: 8250_platform: simplify IRQF

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Message-ID: <20251119092457.826789-7-jirislaby@kernel.org>
Date: Wed, 19 Nov 2025 10:24:57 +0100
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 6/6] serial: 8250_platform: simplify IRQF_SHARED handling

IRQF_SHARED is the only flag handled in __serial8250_isa_init_ports()
and serial8250_probe_platform(). There is no need to precompute the
flags. Instead, initialize port->irqflags directly in the for loop.

Note the "if (bool)" is cheap and these are not hot paths anyway.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
---
 drivers/tty/serial/8250/8250_platform.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_platform.c b/drivers/tty/serial/8250/8250_platform.c
index 4c1166a46a1f..af16a36193bf 100644
--- a/drivers/tty/serial/8250/8250_platform.c
+++ b/drivers/tty/serial/8250/8250_platform.c
@@ -58,7 +58,7 @@ EXPORT_SYMBOL(serial8250_set_isa_configurator);
 
 static void __init __serial8250_isa_init_ports(void)
 {
-	int i, irqflag = 0;
+	int i;
 
 	if (nr_uarts > UART_NR)
 		nr_uarts = UART_NR;
@@ -75,9 +75,6 @@ static void __init __serial8250_isa_init_ports(void)
 	univ8250_port_ops = *univ8250_port_base_ops;
 	univ8250_rsa_support(&univ8250_port_ops);
 
-	if (share_irqs)
-		irqflag = IRQF_SHARED;
-
 	for (i = 0; i < ARRAY_SIZE(old_serial_port) && i < nr_uarts; i++) {
 		struct uart_8250_port *up = serial8250_get_port(i);
 		struct uart_port *port = &up->port;
@@ -92,7 +89,9 @@ static void __init __serial8250_isa_init_ports(void)
 		port->iotype   = old_serial_port[i].io_type;
 		port->regshift = old_serial_port[i].iomem_reg_shift;
 
-		port->irqflags |= irqflag;
+		if (share_irqs)
+			port->irqflags |= IRQF_SHARED;
+
 		if (serial8250_isa_config != NULL)
 			serial8250_isa_config(i, &up->port, &up->capabilities);
 	}
@@ -155,15 +154,12 @@ static int serial8250_probe_acpi(struct platform_device *pdev)
 
 static int serial8250_probe_platform(struct platform_device *dev, struct plat_serial8250_port *p)
 {
-	int ret, i, irqflag = 0;
+	int ret, i;
 
 	struct uart_8250_port *uart __free(kfree) = kzalloc(sizeof(*uart), GFP_KERNEL);
 	if (!uart)
 		return -ENOMEM;
 
-	if (share_irqs)
-		irqflag = IRQF_SHARED;
-
 	for (i = 0; p && p->flags != 0; p++, i++) {
 		uart->port.iobase	= p->iobase;
 		uart->port.membase	= p->membase;
@@ -191,7 +187,10 @@ static int serial8250_probe_platform(struct platform_device *dev, struct plat_se
 		uart->port.get_mctrl	= p->get_mctrl;
 		uart->port.pm		= p->pm;
 		uart->port.dev		= &dev->dev;
-		uart->port.irqflags	|= irqflag;
+
+		if (share_irqs)
+			uart->port.irqflags |= IRQF_SHARED;
+
 		ret = serial8250_register_8250_port(uart);
 		if (ret < 0) {
 			dev_err(&dev->dev, "unable to register port at index %d "
-- 
2.51.1