linux-kernel - [PATCH 5/6] serial: use uart_port_ref

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Message-ID: <20250425111315.1036184-6-jirislaby@kernel.org>
Date: Fri, 25 Apr 2025 13:13:14 +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 5/6] serial: use uart_port_ref_lock() helper

uart_get_icount() and uart_carrier_raised() open code
uart_port_ref_lock(). Use the helper instead.

The difference is we use _irqsave() variants of a spinlock now. But
that's "safer" than _irq().

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
---
 drivers/tty/serial/serial_core.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 52e764be42c4..1f7708a91fc6 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1276,14 +1276,13 @@ static int uart_get_icount(struct tty_struct *tty,
 	struct uart_state *state = tty->driver_data;
 	struct uart_icount cnow;
 	struct uart_port *uport;
+	unsigned long flags;
 
-	uport = uart_port_ref(state);
+	uport = uart_port_ref_lock(state, &flags);
 	if (!uport)
 		return -EIO;
-	uart_port_lock_irq(uport);
 	memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
-	uart_port_unlock_irq(uport);
-	uart_port_deref(uport);
+	uart_port_unlock_deref(uport, flags);
 
 	icount->cts         = cnow.cts;
 	icount->dsr         = cnow.dsr;
@@ -1915,9 +1914,10 @@ static bool uart_carrier_raised(struct tty_port *port)
 {
 	struct uart_state *state = container_of(port, struct uart_state, port);
 	struct uart_port *uport;
+	unsigned long flags;
 	int mctrl;
 
-	uport = uart_port_ref(state);
+	uport = uart_port_ref_lock(state, &flags);
 	/*
 	 * Should never observe uport == NULL since checks for hangup should
 	 * abort the tty_port_block_til_ready() loop before checking for carrier
@@ -1926,11 +1926,9 @@ static bool uart_carrier_raised(struct tty_port *port)
 	 */
 	if (WARN_ON(!uport))
 		return true;
-	uart_port_lock_irq(uport);
 	uart_enable_ms(uport);
 	mctrl = uport->ops->get_mctrl(uport);
-	uart_port_unlock_irq(uport);
-	uart_port_deref(uport);
+	uart_port_unlock_deref(uport, flags);
 
 	return mctrl & TIOCM_CAR;
 }
-- 
2.49.0