linux-kernel - [PATCH 02/24] Input: libps2 - use guard notation when temporarily pausing serio ports

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Message-ID: <20240905041732.2034348-3-dmitry.torokhov@gmail.com>
Date: Wed,  4 Sep 2024 21:17:07 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: linux-input@...r.kernel.org
Cc: Pali Rohár <pali@...nel.org>,
	Helge Deller <deller@....de>,
	"K. Y. Srinivasan" <kys@...rosoft.com>,
	Wei Liu <wei.liu@...nel.org>,
	Dexuan Cui <decui@...rosoft.com>,
	Samuel Holland <samuel@...lland.org>,
	Lyude Paul <thatslyude@...il.com>,
	Michal Simek <michal.simek@....com>,
	Hans de Goede <hdegoede@...hat.com>,
	linux-kernel@...r.kernel.org,
	linux-hyperv@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-sunxi@...ts.linux.dev
Subject: [PATCH 02/24] Input: libps2 - use guard notation when temporarily pausing serio ports

Using guard notation makes the code more compact and error handling
more robust by ensuring that serio ports are resumed in all code paths
when control leaves critical section.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
---
 drivers/input/serio/libps2.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c
index 6d78a1fe00c1..c22ea532276e 100644
--- a/drivers/input/serio/libps2.c
+++ b/drivers/input/serio/libps2.c
@@ -108,13 +108,11 @@ int ps2_sendbyte(struct ps2dev *ps2dev, u8 byte, unsigned int timeout)
 {
 	int retval;
 
-	serio_pause_rx(ps2dev->serio);
+	guard(serio_pause_rx)(ps2dev->serio);
 
 	retval = ps2_do_sendbyte(ps2dev, byte, timeout, 1);
 	dev_dbg(&ps2dev->serio->dev, "%02x - %x\n", byte, ps2dev->nak);
 
-	serio_continue_rx(ps2dev->serio);
-
 	return retval;
 }
 EXPORT_SYMBOL(ps2_sendbyte);
@@ -162,10 +160,10 @@ void ps2_drain(struct ps2dev *ps2dev, size_t maxbytes, unsigned int timeout)
 
 	ps2_begin_command(ps2dev);
 
-	serio_pause_rx(ps2dev->serio);
-	ps2dev->flags = PS2_FLAG_CMD;
-	ps2dev->cmdcnt = maxbytes;
-	serio_continue_rx(ps2dev->serio);
+	scoped_guard(serio_pause_rx, ps2dev->serio) {
+		ps2dev->flags = PS2_FLAG_CMD;
+		ps2dev->cmdcnt = maxbytes;
+	}
 
 	wait_event_timeout(ps2dev->wait,
 			   !(ps2dev->flags & PS2_FLAG_CMD),
@@ -224,9 +222,9 @@ static int ps2_adjust_timeout(struct ps2dev *ps2dev,
 		 * use alternative probe to detect it.
 		 */
 		if (ps2dev->cmdbuf[1] == 0xaa) {
-			serio_pause_rx(ps2dev->serio);
-			ps2dev->flags = 0;
-			serio_continue_rx(ps2dev->serio);
+			scoped_guard(serio_pause_rx, ps2dev->serio)
+				ps2dev->flags = 0;
+
 			timeout = 0;
 		}
 
@@ -235,9 +233,9 @@ static int ps2_adjust_timeout(struct ps2dev *ps2dev,
 		 * won't be 2nd byte of ID response.
 		 */
 		if (!ps2_is_keyboard_id(ps2dev->cmdbuf[1])) {
-			serio_pause_rx(ps2dev->serio);
-			ps2dev->flags = ps2dev->cmdcnt = 0;
-			serio_continue_rx(ps2dev->serio);
+			scoped_guard(serio_pause_rx, ps2dev->serio)
+				ps2dev->flags = ps2dev->cmdcnt = 0;
+
 			timeout = 0;
 		}
 		break;
@@ -283,6 +281,10 @@ int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
 
 	memcpy(send_param, param, send);
 
+	/*
+	 * Not using guard notation because we need to break critical
+	 * section below while waiting for the response.
+	 */
 	serio_pause_rx(ps2dev->serio);
 
 	ps2dev->cmdcnt = receive;
-- 
2.46.0.469.g59c65b2a67-goog