From bf46a2c73f867767afa378be5f00fa99d7f5c73c Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:09 -0700
Subject: [PATCH 01/16] Input: byd - use guard notation when pausing serio port

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.

Link: https://lore.kernel.org/r/20240905041732.2034348-5-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/mouse/byd.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/input/mouse/byd.c b/drivers/input/mouse/byd.c
index 221a553f45cd..654b38d249f3 100644
--- a/drivers/input/mouse/byd.c
+++ b/drivers/input/mouse/byd.c
@@ -254,13 +254,12 @@ static void byd_clear_touch(struct timer_list *t)
 	struct byd_data *priv = from_timer(priv, t, timer);
 	struct psmouse *psmouse = priv->psmouse;
 
-	serio_pause_rx(psmouse->ps2dev.serio);
+	guard(serio_pause_rx)(psmouse->ps2dev.serio);
+
 	priv->touch = false;
 
 	byd_report_input(psmouse);
 
-	serio_continue_rx(psmouse->ps2dev.serio);
-
 	/*
 	 * Move cursor back to center of pad when we lose touch - this
 	 * specifically improves user experience when moving cursor with one
-- 
2.51.0


From 5866065f5698557a3a15116c4e9436055185c4d2 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:10 -0700
Subject: [PATCH 02/16] Input: synaptics - use guard notation when pausing
 serio port

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.

Link: https://lore.kernel.org/r/20240905041732.2034348-6-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/mouse/synaptics.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index 380aa1614442..2735f86c23cc 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -650,9 +650,8 @@ static int synaptics_pt_start(struct serio *serio)
 	struct psmouse *parent = psmouse_from_serio(serio->parent);
 	struct synaptics_data *priv = parent->private;
 
-	serio_pause_rx(parent->ps2dev.serio);
+	guard(serio_pause_rx)(parent->ps2dev.serio);
 	priv->pt_port = serio;
-	serio_continue_rx(parent->ps2dev.serio);
 
 	return 0;
 }
@@ -662,9 +661,8 @@ static void synaptics_pt_stop(struct serio *serio)
 	struct psmouse *parent = psmouse_from_serio(serio->parent);
 	struct synaptics_data *priv = parent->private;
 
-	serio_pause_rx(parent->ps2dev.serio);
+	guard(serio_pause_rx)(parent->ps2dev.serio);
 	priv->pt_port = NULL;
-	serio_continue_rx(parent->ps2dev.serio);
 }
 
 static int synaptics_is_pt_packet(u8 *buf)
-- 
2.51.0


From 30cb2f6350c0f0e3f683fb3430541e6d1945468a Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:11 -0700
Subject: [PATCH 03/16] Input: atkbd - use guard notation when pausing serio
 port

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.

Link: https://lore.kernel.org/r/20240905041732.2034348-7-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/keyboard/atkbd.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/input/keyboard/atkbd.c b/drivers/input/keyboard/atkbd.c
index 5855d4fc6e6a..ec94fcfa4cde 100644
--- a/drivers/input/keyboard/atkbd.c
+++ b/drivers/input/keyboard/atkbd.c
@@ -713,9 +713,9 @@ static int atkbd_event(struct input_dev *dev,
 
 static inline void atkbd_enable(struct atkbd *atkbd)
 {
-	serio_pause_rx(atkbd->ps2dev.serio);
+	guard(serio_pause_rx)(atkbd->ps2dev.serio);
+
 	atkbd->enabled = true;
-	serio_continue_rx(atkbd->ps2dev.serio);
 }
 
 /*
@@ -725,9 +725,9 @@ static inline void atkbd_enable(struct atkbd *atkbd)
 
 static inline void atkbd_disable(struct atkbd *atkbd)
 {
-	serio_pause_rx(atkbd->ps2dev.serio);
+	guard(serio_pause_rx)(atkbd->ps2dev.serio);
+
 	atkbd->enabled = false;
-	serio_continue_rx(atkbd->ps2dev.serio);
 }
 
 static int atkbd_activate(struct atkbd *atkbd)
-- 
2.51.0


From bc656ececfac95a9ff9a58cbfc3042228c18c857 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:12 -0700
Subject: [PATCH 04/16] Input: sunkbd - use guard notation when pausing serio
 port

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.

Link: https://lore.kernel.org/r/20240905041732.2034348-8-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/keyboard/sunkbd.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/input/keyboard/sunkbd.c b/drivers/input/keyboard/sunkbd.c
index 72fb46029710..3299e1919b37 100644
--- a/drivers/input/keyboard/sunkbd.c
+++ b/drivers/input/keyboard/sunkbd.c
@@ -241,9 +241,8 @@ static void sunkbd_reinit(struct work_struct *work)
 
 static void sunkbd_enable(struct sunkbd *sunkbd, bool enable)
 {
-	serio_pause_rx(sunkbd->serio);
-	sunkbd->enabled = enable;
-	serio_continue_rx(sunkbd->serio);
+	scoped_guard(serio_pause_rx, sunkbd->serio)
+		sunkbd->enabled = enable;
 
 	if (!enable) {
 		wake_up_interruptible(&sunkbd->wait);
-- 
2.51.0


From 69a2229b05046eb42258b45df1f43248de8a3472 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:13 -0700
Subject: [PATCH 05/16] Input: synaptics-rmi4 - use guard notation when pausing
 serio port in F03

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.

Link: https://lore.kernel.org/r/20240905041732.2034348-9-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/rmi4/rmi_f03.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/input/rmi4/rmi_f03.c b/drivers/input/rmi4/rmi_f03.c
index 1e11ea30d7bd..e1157ff0f00a 100644
--- a/drivers/input/rmi4/rmi_f03.c
+++ b/drivers/input/rmi4/rmi_f03.c
@@ -61,14 +61,14 @@ void rmi_f03_commit_buttons(struct rmi_function *fn)
 	struct f03_data *f03 = dev_get_drvdata(&fn->dev);
 	struct serio *serio = f03->serio;
 
-	serio_pause_rx(serio);
+	guard(serio_pause_rx)(serio);
+
 	if (serio->drv) {
 		serio->drv->interrupt(serio, PSMOUSE_OOB_EXTRA_BTNS,
 				      SERIO_OOB_DATA);
 		serio->drv->interrupt(serio, f03->overwrite_buttons,
 				      SERIO_OOB_DATA);
 	}
-	serio_continue_rx(serio);
 }
 
 static int rmi_f03_pt_write(struct serio *id, unsigned char val)
-- 
2.51.0


From c91ae81e028f9aa363a38ef46ec5a6ca11a10f10 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:14 -0700
Subject: [PATCH 06/16] Input: elo - use guard notation when pausing serio port

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.

Link: https://lore.kernel.org/r/20240905041732.2034348-10-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/touchscreen/elo.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/input/touchscreen/elo.c b/drivers/input/touchscreen/elo.c
index eb883db55420..ad209e6e82a6 100644
--- a/drivers/input/touchscreen/elo.c
+++ b/drivers/input/touchscreen/elo.c
@@ -225,10 +225,10 @@ static int elo_command_10(struct elo *elo, unsigned char *packet)
 
 	mutex_lock(&elo->cmd_mutex);
 
-	serio_pause_rx(elo->serio);
-	elo->expected_packet = toupper(packet[0]);
-	init_completion(&elo->cmd_done);
-	serio_continue_rx(elo->serio);
+	scoped_guard(serio_pause_rx, elo->serio) {
+		elo->expected_packet = toupper(packet[0]);
+		init_completion(&elo->cmd_done);
+	}
 
 	if (serio_write(elo->serio, ELO10_LEAD_BYTE))
 		goto out;
-- 
2.51.0


From 44f920069911437dbce84084de02b5cba4ba94f7 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:15 -0700
Subject: [PATCH 07/16] Input: gscps2 - use guard notation when acquiring
 spinlock

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

Link: https://lore.kernel.org/r/20240905041732.2034348-11-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/serio/gscps2.c | 114 +++++++++++++++++++----------------
 1 file changed, 62 insertions(+), 52 deletions(-)

diff --git a/drivers/input/serio/gscps2.c b/drivers/input/serio/gscps2.c
index d94c01eb3fc9..cf0603d1a113 100644
--- a/drivers/input/serio/gscps2.c
+++ b/drivers/input/serio/gscps2.c
@@ -145,7 +145,6 @@ static void gscps2_flush(struct gscps2port *ps2port)
 
 static inline int gscps2_writeb_output(struct gscps2port *ps2port, u8 data)
 {
-	unsigned long flags;
 	char __iomem *addr = ps2port->addr;
 
 	if (!wait_TBE(addr)) {
@@ -156,9 +155,8 @@ static inline int gscps2_writeb_output(struct gscps2port *ps2port, u8 data)
 	while (gscps2_readb_status(addr) & GSC_STAT_RBNE)
 		/* wait */;
 
-	spin_lock_irqsave(&ps2port->lock, flags);
-	writeb(data, addr+GSC_XMTDATA);
-	spin_unlock_irqrestore(&ps2port->lock, flags);
+	scoped_guard(spinlock_irqsave, &ps2port->lock)
+		writeb(data, addr+GSC_XMTDATA);
 
 	/* this is ugly, but due to timing of the port it seems to be necessary. */
 	mdelay(6);
@@ -177,19 +175,19 @@ static inline int gscps2_writeb_output(struct gscps2port *ps2port, u8 data)
 
 static void gscps2_enable(struct gscps2port *ps2port, int enable)
 {
-	unsigned long flags;
 	u8 data;
 
 	/* now enable/disable the port */
-	spin_lock_irqsave(&ps2port->lock, flags);
-	gscps2_flush(ps2port);
-	data = gscps2_readb_control(ps2port->addr);
-	if (enable)
-		data |= GSC_CTRL_ENBL;
-	else
-		data &= ~GSC_CTRL_ENBL;
-	gscps2_writeb_control(data, ps2port->addr);
-	spin_unlock_irqrestore(&ps2port->lock, flags);
+	scoped_guard(spinlock_irqsave, &ps2port->lock) {
+		gscps2_flush(ps2port);
+		data = gscps2_readb_control(ps2port->addr);
+		if (enable)
+			data |= GSC_CTRL_ENBL;
+		else
+			data &= ~GSC_CTRL_ENBL;
+		gscps2_writeb_control(data, ps2port->addr);
+	}
+
 	wait_TBE(ps2port->addr);
 	gscps2_flush(ps2port);
 }
@@ -203,15 +201,56 @@ static void gscps2_reset(struct gscps2port *ps2port)
 	unsigned long flags;
 
 	/* reset the interface */
-	spin_lock_irqsave(&ps2port->lock, flags);
+	guard(spinlock_irqsave)(&ps2port->lock);
 	gscps2_flush(ps2port);
 	writeb(0xff, ps2port->addr + GSC_RESET);
 	gscps2_flush(ps2port);
-	spin_unlock_irqrestore(&ps2port->lock, flags);
 }
 
 static LIST_HEAD(ps2port_list);
 
+static void gscps2_read_data(struct gscps2port *ps2port)
+{
+	u8 status;
+
+	do {
+		status = gscps2_readb_status(ps2port->addr);
+		if (!(status & GSC_STAT_RBNE))
+			break;
+
+		ps2port->buffer[ps2port->append].ste = status;
+		ps2port->buffer[ps2port->append].data =
+				gscps2_readb_input(ps2port->addr);
+	} while (true);
+}
+
+static bool gscps2_report_data(struct gscps2port *ps2port)
+{
+	unsigned int rxflags;
+	u8 data, status;
+
+	while (ps2port->act != ps2port->append) {
+		/*
+		 * Did new data arrived while we read existing data ?
+		 * If yes, exit now and let the new irq handler start
+		 * over again.
+		 */
+		if (gscps2_readb_status(ps2port->addr) & GSC_STAT_CMPINTR)
+			return true;
+
+		status = ps2port->buffer[ps2port->act].str;
+		data   = ps2port->buffer[ps2port->act].data;
+
+		ps2port->act = (ps2port->act + 1) & BUFFER_SIZE;
+		rxflags = ((status & GSC_STAT_TERR) ? SERIO_TIMEOUT : 0 ) |
+			  ((status & GSC_STAT_PERR) ? SERIO_PARITY  : 0 );
+
+		serio_interrupt(ps2port->port, data, rxflags);
+	}
+
+	return false;
+}
+
 /**
  * gscps2_interrupt() - Interruption service routine
  *
@@ -229,47 +268,18 @@ static irqreturn_t gscps2_interrupt(int irq, void *dev)
 	struct gscps2port *ps2port;
 
 	list_for_each_entry(ps2port, &ps2port_list, node) {
+		guard(spinlock_irqsave)(&ps2port->lock);
 
-	  unsigned long flags;
-	  spin_lock_irqsave(&ps2port->lock, flags);
-
-	  while ( (ps2port->buffer[ps2port->append].str =
-		   gscps2_readb_status(ps2port->addr)) & GSC_STAT_RBNE ) {
-		ps2port->buffer[ps2port->append].data =
-				gscps2_readb_input(ps2port->addr);
-		ps2port->append = ((ps2port->append+1) & BUFFER_SIZE);
-	  }
-
-	  spin_unlock_irqrestore(&ps2port->lock, flags);
-
+		gscps2_read_data(ps2port);
 	} /* list_for_each_entry */
 
 	/* all data was read from the ports - now report the data to upper layer */
-
 	list_for_each_entry(ps2port, &ps2port_list, node) {
-
-	  while (ps2port->act != ps2port->append) {
-
-	    unsigned int rxflags;
-	    u8 data, status;
-
-	    /* Did new data arrived while we read existing data ?
-	       If yes, exit now and let the new irq handler start over again */
-	    if (gscps2_readb_status(ps2port->addr) & GSC_STAT_CMPINTR)
-		return IRQ_HANDLED;
-
-	    status = ps2port->buffer[ps2port->act].str;
-	    data   = ps2port->buffer[ps2port->act].data;
-
-	    ps2port->act = ((ps2port->act+1) & BUFFER_SIZE);
-	    rxflags =	((status & GSC_STAT_TERR) ? SERIO_TIMEOUT : 0 ) |
-			((status & GSC_STAT_PERR) ? SERIO_PARITY  : 0 );
-
-	    serio_interrupt(ps2port->port, data, rxflags);
-
-	  } /* while() */
-
-	} /* list_for_each_entry */
+		if (gscps2_report_data(ps2port)) {
+			/* More data ready - break early to restart interrupt */
+			break;
+		}
+	}
 
 	return IRQ_HANDLED;
 }
-- 
2.51.0


From 79d01971fad360256167c4665907f1fe5ebd5e41 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:16 -0700
Subject: [PATCH 08/16] Input: hyperv-keyboard - use guard notation when
 acquiring spinlock

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

Link: https://lore.kernel.org/r/20240905041732.2034348-12-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/serio/hyperv-keyboard.c | 38 +++++++++++++--------------
 1 file changed, 18 insertions(+), 20 deletions(-)

diff --git a/drivers/input/serio/hyperv-keyboard.c b/drivers/input/serio/hyperv-keyboard.c
index 31d9dacd2fd1..0ee7505427ac 100644
--- a/drivers/input/serio/hyperv-keyboard.c
+++ b/drivers/input/serio/hyperv-keyboard.c
@@ -102,7 +102,6 @@ static void hv_kbd_on_receive(struct hv_device *hv_dev,
 {
 	struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);
 	struct synth_kbd_keystroke *ks_msg;
-	unsigned long flags;
 	u32 msg_type = __le32_to_cpu(msg->header.type);
 	u32 info;
 	u16 scan_code;
@@ -147,21 +146,22 @@ static void hv_kbd_on_receive(struct hv_device *hv_dev,
 		/*
 		 * Inject the information through the serio interrupt.
 		 */
-		spin_lock_irqsave(&kbd_dev->lock, flags);
-		if (kbd_dev->started) {
-			if (info & IS_E0)
-				serio_interrupt(kbd_dev->hv_serio,
-						XTKBD_EMUL0, 0);
-			if (info & IS_E1)
-				serio_interrupt(kbd_dev->hv_serio,
-						XTKBD_EMUL1, 0);
-			scan_code = __le16_to_cpu(ks_msg->make_code);
-			if (info & IS_BREAK)
-				scan_code |= XTKBD_RELEASE;
+		scoped_guard(spinlock_irqsave, &kbd_dev->lock) {
+			if (kbd_dev->started) {
+				if (info & IS_E0)
+					serio_interrupt(kbd_dev->hv_serio,
+							XTKBD_EMUL0, 0);
+				if (info & IS_E1)
+					serio_interrupt(kbd_dev->hv_serio,
+							XTKBD_EMUL1, 0);
+				scan_code = __le16_to_cpu(ks_msg->make_code);
+				if (info & IS_BREAK)
+					scan_code |= XTKBD_RELEASE;
 
-			serio_interrupt(kbd_dev->hv_serio, scan_code, 0);
+				serio_interrupt(kbd_dev->hv_serio,
+						scan_code, 0);
+			}
 		}
-		spin_unlock_irqrestore(&kbd_dev->lock, flags);
 
 		/*
 		 * Only trigger a wakeup on key down, otherwise
@@ -292,11 +292,10 @@ static int hv_kbd_connect_to_vsp(struct hv_device *hv_dev)
 static int hv_kbd_start(struct serio *serio)
 {
 	struct hv_kbd_dev *kbd_dev = serio->port_data;
-	unsigned long flags;
 
-	spin_lock_irqsave(&kbd_dev->lock, flags);
+	guard(spinlock_irqsave)(&kbd_dev->lock);
+
 	kbd_dev->started = true;
-	spin_unlock_irqrestore(&kbd_dev->lock, flags);
 
 	return 0;
 }
@@ -304,11 +303,10 @@ static int hv_kbd_start(struct serio *serio)
 static void hv_kbd_stop(struct serio *serio)
 {
 	struct hv_kbd_dev *kbd_dev = serio->port_data;
-	unsigned long flags;
 
-	spin_lock_irqsave(&kbd_dev->lock, flags);
+	guard(spinlock_irqsave)(&kbd_dev->lock);
+
 	kbd_dev->started = false;
-	spin_unlock_irqrestore(&kbd_dev->lock, flags);
 }
 
 static int hv_kbd_probe(struct hv_device *hv_dev,
-- 
2.51.0


From c374a0cdab372c350ce9e2f8cb438d6175bac9f2 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:17 -0700
Subject: [PATCH 09/16] Input: i8042 - tease apart interrupt handler

In preparation to using guard notation when acquiring mutexes and
spinlocks factor out handling of active multiplexing mode from
i8042_interrupt().

Link: https://lore.kernel.org/r/20240905041732.2034348-13-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/serio/i8042.c | 139 +++++++++++++++++++++---------------
 1 file changed, 83 insertions(+), 56 deletions(-)

diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 8ec4872b4471..674cd155ec8f 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -178,7 +178,7 @@ static unsigned char i8042_suppress_kbd_ack;
 static struct platform_device *i8042_platform_device;
 static struct notifier_block i8042_kbd_bind_notifier_block;
 
-static irqreturn_t i8042_interrupt(int irq, void *dev_id);
+static bool i8042_handle_data(int irq);
 static bool (*i8042_platform_filter)(unsigned char data, unsigned char str,
 				     struct serio *serio);
 
@@ -434,7 +434,7 @@ static void i8042_port_close(struct serio *serio)
 	 * See if there is any data appeared while we were messing with
 	 * port state.
 	 */
-	i8042_interrupt(0, NULL);
+	i8042_handle_data(0);
 }
 
 /*
@@ -518,12 +518,68 @@ static bool i8042_filter(unsigned char data, unsigned char str,
 }
 
 /*
- * i8042_interrupt() is the most important function in this driver -
- * it handles the interrupts from the i8042, and sends incoming bytes
- * to the upper layers.
+ * i8042_handle_mux() handles case when data is coming from one of
+ * the multiplexed ports. It would be simple if not for quirks with
+ * handling errors:
+ *
+ * When MUXERR condition is signalled the data register can only contain
+ * 0xfd, 0xfe or 0xff if implementation follows the spec. Unfortunately
+ * it is not always the case. Some KBCs also report 0xfc when there is
+ * nothing connected to the port while others sometimes get confused which
+ * port the data came from and signal error leaving the data intact. They
+ * _do not_ revert to legacy mode (actually I've never seen KBC reverting
+ * to legacy mode yet, when we see one we'll add proper handling).
+ * Anyway, we process 0xfc, 0xfd, 0xfe and 0xff as timeouts, and for the
+ * rest assume that the data came from the same serio last byte
+ * was transmitted (if transmission happened not too long ago).
  */
+static int i8042_handle_mux(u8 str, u8 *data, unsigned int *dfl)
+{
+	static unsigned long last_transmit;
+	static unsigned long last_port;
+	unsigned int mux_port;
+
+	mux_port = (str >> 6) & 3;
+	*dfl = 0;
+
+	if (str & I8042_STR_MUXERR) {
+		dbg("MUX error, status is %02x, data is %02x\n",
+		    str, *data);
+
+		switch (*data) {
+		default:
+			if (time_before(jiffies, last_transmit + HZ/10)) {
+				mux_port = last_port;
+				break;
+			}
+			fallthrough;	/* report timeout */
+		case 0xfc:
+		case 0xfd:
+		case 0xfe:
+			*dfl = SERIO_TIMEOUT;
+			*data = 0xfe;
+			break;
+		case 0xff:
+			*dfl = SERIO_PARITY;
+			*data = 0xfe;
+			break;
+		}
+	}
 
-static irqreturn_t i8042_interrupt(int irq, void *dev_id)
+	last_port = mux_port;
+	last_transmit = jiffies;
+
+	return I8042_MUX_PORT_NO + mux_port;
+}
+
+/*
+ * i8042_handle_data() is the most important function in this driver -
+ * it reads the data from the i8042, determines its destination serio
+ * port, and sends received byte to the upper layers.
+ *
+ * Returns true if there was data waiting, false otherwise.
+ */
+static bool i8042_handle_data(int irq)
 {
 	struct i8042_port *port;
 	struct serio *serio;
@@ -532,63 +588,24 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
 	unsigned int dfl;
 	unsigned int port_no;
 	bool filtered;
-	int ret = 1;
 
 	spin_lock_irqsave(&i8042_lock, flags);
 
 	str = i8042_read_status();
 	if (unlikely(~str & I8042_STR_OBF)) {
 		spin_unlock_irqrestore(&i8042_lock, flags);
-		if (irq)
-			dbg("Interrupt %d, without any data\n", irq);
-		ret = 0;
-		goto out;
+		return false;
 	}
 
 	data = i8042_read_data();
 
 	if (i8042_mux_present && (str & I8042_STR_AUXDATA)) {
-		static unsigned long last_transmit;
-		static unsigned char last_str;
-
-		dfl = 0;
-		if (str & I8042_STR_MUXERR) {
-			dbg("MUX error, status is %02x, data is %02x\n",
-			    str, data);
-/*
- * When MUXERR condition is signalled the data register can only contain
- * 0xfd, 0xfe or 0xff if implementation follows the spec. Unfortunately
- * it is not always the case. Some KBCs also report 0xfc when there is
- * nothing connected to the port while others sometimes get confused which
- * port the data came from and signal error leaving the data intact. They
- * _do not_ revert to legacy mode (actually I've never seen KBC reverting
- * to legacy mode yet, when we see one we'll add proper handling).
- * Anyway, we process 0xfc, 0xfd, 0xfe and 0xff as timeouts, and for the
- * rest assume that the data came from the same serio last byte
- * was transmitted (if transmission happened not too long ago).
- */
-
-			switch (data) {
-				default:
-					if (time_before(jiffies, last_transmit + HZ/10)) {
-						str = last_str;
-						break;
-					}
-					fallthrough;	/* report timeout */
-				case 0xfc:
-				case 0xfd:
-				case 0xfe: dfl = SERIO_TIMEOUT; data = 0xfe; break;
-				case 0xff: dfl = SERIO_PARITY;  data = 0xfe; break;
-			}
-		}
-
-		port_no = I8042_MUX_PORT_NO + ((str >> 6) & 3);
-		last_str = str;
-		last_transmit = jiffies;
+		port_no = i8042_handle_mux(str, &data, &dfl);
 	} else {
 
-		dfl = ((str & I8042_STR_PARITY) ? SERIO_PARITY : 0) |
-		      ((str & I8042_STR_TIMEOUT && !i8042_notimeout) ? SERIO_TIMEOUT : 0);
+		dfl = (str & I8042_STR_PARITY) ? SERIO_PARITY : 0;
+		if ((str & I8042_STR_TIMEOUT) && !i8042_notimeout)
+			dfl |= SERIO_TIMEOUT;
 
 		port_no = (str & I8042_STR_AUXDATA) ?
 				I8042_AUX_PORT_NO : I8042_KBD_PORT_NO;
@@ -609,8 +626,17 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
 	if (likely(serio && !filtered))
 		serio_interrupt(serio, data, dfl);
 
- out:
-	return IRQ_RETVAL(ret);
+	return true;
+}
+
+static irqreturn_t i8042_interrupt(int irq, void *dev_id)
+{
+	if (unlikely(!i8042_handle_data(irq))) {
+		dbg("Interrupt %d, without any data\n", irq);
+		return IRQ_NONE;
+	}
+
+	return IRQ_HANDLED;
 }
 
 /*
@@ -1216,13 +1242,14 @@ static int i8042_controller_resume(bool s2r_wants_reset)
 	if (i8042_mux_present) {
 		if (i8042_set_mux_mode(true, NULL) || i8042_enable_mux_ports())
 			pr_warn("failed to resume active multiplexor, mouse won't work\n");
-	} else if (i8042_ports[I8042_AUX_PORT_NO].serio)
+	} else if (i8042_ports[I8042_AUX_PORT_NO].serio) {
 		i8042_enable_aux_port();
+	}
 
 	if (i8042_ports[I8042_KBD_PORT_NO].serio)
 		i8042_enable_kbd_port();
 
-	i8042_interrupt(0, NULL);
+	i8042_handle_data(0);
 
 	return 0;
 }
@@ -1253,7 +1280,7 @@ static int i8042_pm_suspend(struct device *dev)
 static int i8042_pm_resume_noirq(struct device *dev)
 {
 	if (i8042_forcenorestore || !pm_resume_via_firmware())
-		i8042_interrupt(0, NULL);
+		i8042_handle_data(0);
 
 	return 0;
 }
@@ -1290,7 +1317,7 @@ static int i8042_pm_resume(struct device *dev)
 
 static int i8042_pm_thaw(struct device *dev)
 {
-	i8042_interrupt(0, NULL);
+	i8042_handle_data(0);
 
 	return 0;
 }
-- 
2.51.0


From 7dc406b736b9acf01379d2235d97bb4873b504e7 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:18 -0700
Subject: [PATCH 10/16] Input: i8042 - use guard notation when acquiring
 spinlock

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

Link: https://lore.kernel.org/r/20240905041732.2034348-14-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/serio/i8042.c | 204 +++++++++++++++---------------------
 1 file changed, 82 insertions(+), 122 deletions(-)

diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 674cd155ec8f..86916fe3925f 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -197,42 +197,26 @@ EXPORT_SYMBOL(i8042_unlock_chip);
 int i8042_install_filter(bool (*filter)(unsigned char data, unsigned char str,
 					struct serio *serio))
 {
-	unsigned long flags;
-	int ret = 0;
+	guard(spinlock_irqsave)(&i8042_lock);
 
-	spin_lock_irqsave(&i8042_lock, flags);
-
-	if (i8042_platform_filter) {
-		ret = -EBUSY;
-		goto out;
-	}
+	if (i8042_platform_filter)
+		return -EBUSY;
 
 	i8042_platform_filter = filter;
-
-out:
-	spin_unlock_irqrestore(&i8042_lock, flags);
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(i8042_install_filter);
 
 int i8042_remove_filter(bool (*filter)(unsigned char data, unsigned char str,
 				       struct serio *port))
 {
-	unsigned long flags;
-	int ret = 0;
-
-	spin_lock_irqsave(&i8042_lock, flags);
+	guard(spinlock_irqsave)(&i8042_lock);
 
-	if (i8042_platform_filter != filter) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (i8042_platform_filter != filter)
+		return -EINVAL;
 
 	i8042_platform_filter = NULL;
-
-out:
-	spin_unlock_irqrestore(&i8042_lock, flags);
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(i8042_remove_filter);
 
@@ -271,28 +255,22 @@ static int i8042_wait_write(void)
 
 static int i8042_flush(void)
 {
-	unsigned long flags;
 	unsigned char data, str;
 	int count = 0;
-	int retval = 0;
 
-	spin_lock_irqsave(&i8042_lock, flags);
+	guard(spinlock_irqsave)(&i8042_lock);
 
 	while ((str = i8042_read_status()) & I8042_STR_OBF) {
-		if (count++ < I8042_BUFFER_SIZE) {
-			udelay(50);
-			data = i8042_read_data();
-			dbg("%02x <- i8042 (flush, %s)\n",
-			    data, str & I8042_STR_AUXDATA ? "aux" : "kbd");
-		} else {
-			retval = -EIO;
-			break;
-		}
-	}
+		if (count++ >= I8042_BUFFER_SIZE)
+			return -EIO;
 
-	spin_unlock_irqrestore(&i8042_lock, flags);
+		udelay(50);
+		data = i8042_read_data();
+		dbg("%02x <- i8042 (flush, %s)\n",
+		    data, str & I8042_STR_AUXDATA ? "aux" : "kbd");
+	}
 
-	return retval;
+	return 0;
 }
 
 /*
@@ -349,17 +327,12 @@ static int __i8042_command(unsigned char *param, int command)
 
 int i8042_command(unsigned char *param, int command)
 {
-	unsigned long flags;
-	int retval;
-
 	if (!i8042_present)
 		return -1;
 
-	spin_lock_irqsave(&i8042_lock, flags);
-	retval = __i8042_command(param, command);
-	spin_unlock_irqrestore(&i8042_lock, flags);
+	guard(spinlock_irqsave)(&i8042_lock);
 
-	return retval;
+	return __i8042_command(param, command);
 }
 EXPORT_SYMBOL(i8042_command);
 
@@ -369,19 +342,18 @@ EXPORT_SYMBOL(i8042_command);
 
 static int i8042_kbd_write(struct serio *port, unsigned char c)
 {
-	unsigned long flags;
-	int retval = 0;
+	int error;
 
-	spin_lock_irqsave(&i8042_lock, flags);
+	guard(spinlock_irqsave)(&i8042_lock);
 
-	if (!(retval = i8042_wait_write())) {
-		dbg("%02x -> i8042 (kbd-data)\n", c);
-		i8042_write_data(c);
-	}
+	error = i8042_wait_write();
+	if (error)
+		return error;
 
-	spin_unlock_irqrestore(&i8042_lock, flags);
+	dbg("%02x -> i8042 (kbd-data)\n", c);
+	i8042_write_data(c);
 
-	return retval;
+	return 0;
 }
 
 /*
@@ -460,9 +432,8 @@ static int i8042_start(struct serio *serio)
 		device_set_wakeup_enable(&serio->dev, true);
 	}
 
-	spin_lock_irq(&i8042_lock);
+	guard(spinlock_irq)(&i8042_lock);
 	port->exists = true;
-	spin_unlock_irq(&i8042_lock);
 
 	return 0;
 }
@@ -476,10 +447,10 @@ static void i8042_stop(struct serio *serio)
 {
 	struct i8042_port *port = serio->port_data;
 
-	spin_lock_irq(&i8042_lock);
-	port->exists = false;
-	port->serio = NULL;
-	spin_unlock_irq(&i8042_lock);
+	scoped_guard(spinlock_irq, &i8042_lock) {
+		port->exists = false;
+		port->serio = NULL;
+	}
 
 	/*
 	 * We need to make sure that interrupt handler finishes using
@@ -583,45 +554,41 @@ static bool i8042_handle_data(int irq)
 {
 	struct i8042_port *port;
 	struct serio *serio;
-	unsigned long flags;
 	unsigned char str, data;
 	unsigned int dfl;
 	unsigned int port_no;
 	bool filtered;
 
-	spin_lock_irqsave(&i8042_lock, flags);
-
-	str = i8042_read_status();
-	if (unlikely(~str & I8042_STR_OBF)) {
-		spin_unlock_irqrestore(&i8042_lock, flags);
-		return false;
-	}
-
-	data = i8042_read_data();
+	scoped_guard(spinlock_irqsave, &i8042_lock) {
+		str = i8042_read_status();
+		if (unlikely(~str & I8042_STR_OBF))
+			return false;
 
-	if (i8042_mux_present && (str & I8042_STR_AUXDATA)) {
-		port_no = i8042_handle_mux(str, &data, &dfl);
-	} else {
+		data = i8042_read_data();
 
-		dfl = (str & I8042_STR_PARITY) ? SERIO_PARITY : 0;
-		if ((str & I8042_STR_TIMEOUT) && !i8042_notimeout)
-			dfl |= SERIO_TIMEOUT;
+		if (i8042_mux_present && (str & I8042_STR_AUXDATA)) {
+			port_no = i8042_handle_mux(str, &data, &dfl);
+		} else {
 
-		port_no = (str & I8042_STR_AUXDATA) ?
-				I8042_AUX_PORT_NO : I8042_KBD_PORT_NO;
-	}
+			dfl = (str & I8042_STR_PARITY) ? SERIO_PARITY : 0;
+			if ((str & I8042_STR_TIMEOUT) && !i8042_notimeout)
+				dfl |= SERIO_TIMEOUT;
 
-	port = &i8042_ports[port_no];
-	serio = port->exists ? port->serio : NULL;
+			port_no = (str & I8042_STR_AUXDATA) ?
+					I8042_AUX_PORT_NO : I8042_KBD_PORT_NO;
+		}
 
-	filter_dbg(port->driver_bound, data, "<- i8042 (interrupt, %d, %d%s%s)\n",
-		   port_no, irq,
-		   dfl & SERIO_PARITY ? ", bad parity" : "",
-		   dfl & SERIO_TIMEOUT ? ", timeout" : "");
+		port = &i8042_ports[port_no];
+		serio = port->exists ? port->serio : NULL;
 
-	filtered = i8042_filter(data, str, serio);
+		filter_dbg(port->driver_bound,
+			   data, "<- i8042 (interrupt, %d, %d%s%s)\n",
+			   port_no, irq,
+			   dfl & SERIO_PARITY ? ", bad parity" : "",
+			   dfl & SERIO_TIMEOUT ? ", timeout" : "");
 
-	spin_unlock_irqrestore(&i8042_lock, flags);
+		filtered = i8042_filter(data, str, serio);
+	}
 
 	if (likely(serio && !filtered))
 		serio_interrupt(serio, data, dfl);
@@ -779,24 +746,22 @@ static bool i8042_irq_being_tested;
 
 static irqreturn_t i8042_aux_test_irq(int irq, void *dev_id)
 {
-	unsigned long flags;
 	unsigned char str, data;
-	int ret = 0;
 
-	spin_lock_irqsave(&i8042_lock, flags);
+	guard(spinlock_irqsave)(&i8042_lock);
+
 	str = i8042_read_status();
-	if (str & I8042_STR_OBF) {
-		data = i8042_read_data();
-		dbg("%02x <- i8042 (aux_test_irq, %s)\n",
-		    data, str & I8042_STR_AUXDATA ? "aux" : "kbd");
-		if (i8042_irq_being_tested &&
-		    data == 0xa5 && (str & I8042_STR_AUXDATA))
-			complete(&i8042_aux_irq_delivered);
-		ret = 1;
-	}
-	spin_unlock_irqrestore(&i8042_lock, flags);
+	if (!(str & I8042_STR_OBF))
+		return IRQ_NONE;
+
+	data = i8042_read_data();
+	dbg("%02x <- i8042 (aux_test_irq, %s)\n",
+	    data, str & I8042_STR_AUXDATA ? "aux" : "kbd");
+
+	if (i8042_irq_being_tested && data == 0xa5 && (str & I8042_STR_AUXDATA))
+		complete(&i8042_aux_irq_delivered);
 
-	return IRQ_RETVAL(ret);
+	return IRQ_HANDLED;
 }
 
 /*
@@ -837,7 +802,6 @@ static int i8042_check_aux(void)
 	int retval = -1;
 	bool irq_registered = false;
 	bool aux_loop_broken = false;
-	unsigned long flags;
 	unsigned char param;
 
 /*
@@ -921,18 +885,15 @@ static int i8042_check_aux(void)
 	if (i8042_enable_aux_port())
 		goto out;
 
-	spin_lock_irqsave(&i8042_lock, flags);
-
-	init_completion(&i8042_aux_irq_delivered);
-	i8042_irq_being_tested = true;
-
-	param = 0xa5;
-	retval = __i8042_command(&param, I8042_CMD_AUX_LOOP & 0xf0ff);
-
-	spin_unlock_irqrestore(&i8042_lock, flags);
+	scoped_guard(spinlock_irqsave, &i8042_lock) {
+		init_completion(&i8042_aux_irq_delivered);
+		i8042_irq_being_tested = true;
 
-	if (retval)
-		goto out;
+		param = 0xa5;
+		retval = __i8042_command(&param, I8042_CMD_AUX_LOOP & 0xf0ff);
+		if (retval)
+			goto out;
+	}
 
 	if (wait_for_completion_timeout(&i8042_aux_irq_delivered,
 					msecs_to_jiffies(250)) == 0) {
@@ -1020,7 +981,6 @@ static int i8042_controller_selftest(void)
 
 static int i8042_controller_init(void)
 {
-	unsigned long flags;
 	int n = 0;
 	unsigned char ctr[2];
 
@@ -1057,14 +1017,14 @@ static int i8042_controller_init(void)
  * Handle keylock.
  */
 
-	spin_lock_irqsave(&i8042_lock, flags);
-	if (~i8042_read_status() & I8042_STR_KEYLOCK) {
-		if (i8042_unlock)
-			i8042_ctr |= I8042_CTR_IGNKEYLOCK;
-		else
-			pr_warn("Warning: Keylock active\n");
+	scoped_guard(spinlock_irqsave, &i8042_lock) {
+		if (~i8042_read_status() & I8042_STR_KEYLOCK) {
+			if (i8042_unlock)
+				i8042_ctr |= I8042_CTR_IGNKEYLOCK;
+			else
+				pr_warn("Warning: Keylock active\n");
+		}
 	}
-	spin_unlock_irqrestore(&i8042_lock, flags);
 
 /*
  * If the chip is configured into nontranslated mode by the BIOS, don't
-- 
2.51.0


From 31b6b9a46d0af9c1ec7133e41302b3ef76016b04 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:19 -0700
Subject: [PATCH 11/16] Input: ps2-gpio - use guard notation when acquiring
 mutex

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

Link: https://lore.kernel.org/r/20240905041732.2034348-15-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/serio/ps2-gpio.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/input/serio/ps2-gpio.c b/drivers/input/serio/ps2-gpio.c
index 3a431395c464..3e4ae2cc6552 100644
--- a/drivers/input/serio/ps2-gpio.c
+++ b/drivers/input/serio/ps2-gpio.c
@@ -133,12 +133,12 @@ static int ps2_gpio_write(struct serio *serio, unsigned char val)
 	int ret = 0;
 
 	if (in_task()) {
-		mutex_lock(&drvdata->tx.mutex);
+		guard(mutex)(&drvdata->tx.mutex);
+
 		__ps2_gpio_write(serio, val);
 		if (!wait_for_completion_timeout(&drvdata->tx.complete,
 						 msecs_to_jiffies(10000)))
 			ret = SERIO_TIMEOUT;
-		mutex_unlock(&drvdata->tx.mutex);
 	} else {
 		__ps2_gpio_write(serio, val);
 	}
-- 
2.51.0


From 9d58ae181d0dbaf445a18079528b8e3b7f669f9b Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:20 -0700
Subject: [PATCH 12/16] Input: ps2mult - use guard notation when acquiring
 spinlock

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

Link: https://lore.kernel.org/r/20240905041732.2034348-16-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/serio/ps2mult.c | 25 +++++++------------------
 1 file changed, 7 insertions(+), 18 deletions(-)

diff --git a/drivers/input/serio/ps2mult.c b/drivers/input/serio/ps2mult.c
index 937ecdea491d..b96cee52fc52 100644
--- a/drivers/input/serio/ps2mult.c
+++ b/drivers/input/serio/ps2mult.c
@@ -76,9 +76,8 @@ static int ps2mult_serio_write(struct serio *serio, unsigned char data)
 	struct ps2mult *psm = serio_get_drvdata(mx_port);
 	struct ps2mult_port *port = serio->port_data;
 	bool need_escape;
-	unsigned long flags;
 
-	spin_lock_irqsave(&psm->lock, flags);
+	guard(spinlock_irqsave)(&psm->lock);
 
 	if (psm->out_port != port)
 		ps2mult_select_port(psm, port);
@@ -93,8 +92,6 @@ static int ps2mult_serio_write(struct serio *serio, unsigned char data)
 
 	serio_write(mx_port, data);
 
-	spin_unlock_irqrestore(&psm->lock, flags);
-
 	return 0;
 }
 
@@ -102,11 +99,10 @@ static int ps2mult_serio_start(struct serio *serio)
 {
 	struct ps2mult *psm = serio_get_drvdata(serio->parent);
 	struct ps2mult_port *port = serio->port_data;
-	unsigned long flags;
 
-	spin_lock_irqsave(&psm->lock, flags);
+	guard(spinlock_irqsave)(&psm->lock);
+
 	port->registered = true;
-	spin_unlock_irqrestore(&psm->lock, flags);
 
 	return 0;
 }
@@ -115,11 +111,10 @@ static void ps2mult_serio_stop(struct serio *serio)
 {
 	struct ps2mult *psm = serio_get_drvdata(serio->parent);
 	struct ps2mult_port *port = serio->port_data;
-	unsigned long flags;
 
-	spin_lock_irqsave(&psm->lock, flags);
+	guard(spinlock_irqsave)(&psm->lock);
+
 	port->registered = false;
-	spin_unlock_irqrestore(&psm->lock, flags);
 }
 
 static int ps2mult_create_port(struct ps2mult *psm, int i)
@@ -148,16 +143,12 @@ static int ps2mult_create_port(struct ps2mult *psm, int i)
 
 static void ps2mult_reset(struct ps2mult *psm)
 {
-	unsigned long flags;
-
-	spin_lock_irqsave(&psm->lock, flags);
+	guard(spinlock_irqsave)(&psm->lock);
 
 	serio_write(psm->mx_serio, PS2MULT_SESSION_END);
 	serio_write(psm->mx_serio, PS2MULT_SESSION_START);
 
 	ps2mult_select_port(psm, &psm->ports[PS2MULT_KBD_PORT]);
-
-	spin_unlock_irqrestore(&psm->lock, flags);
 }
 
 static int ps2mult_connect(struct serio *serio, struct serio_driver *drv)
@@ -234,11 +225,10 @@ static irqreturn_t ps2mult_interrupt(struct serio *serio,
 {
 	struct ps2mult *psm = serio_get_drvdata(serio);
 	struct ps2mult_port *in_port;
-	unsigned long flags;
 
 	dev_dbg(&serio->dev, "Received %02x flags %02x\n", data, dfl);
 
-	spin_lock_irqsave(&psm->lock, flags);
+	guard(spinlock_irqsave)(&psm->lock);
 
 	if (psm->escape) {
 		psm->escape = false;
@@ -285,7 +275,6 @@ static irqreturn_t ps2mult_interrupt(struct serio *serio,
 	}
 
  out:
-	spin_unlock_irqrestore(&psm->lock, flags);
 	return IRQ_HANDLED;
 }
 
-- 
2.51.0


From 424bc7e00a3495afb6ea85696b530b3f47bc24fb Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:21 -0700
Subject: [PATCH 13/16] Input: q40kbd - use guard notation when acquiring
 spinlock

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

Link: https://lore.kernel.org/r/20240905041732.2034348-17-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/serio/q40kbd.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/input/serio/q40kbd.c b/drivers/input/serio/q40kbd.c
index cd4d5be946a3..cdd5c4ef9b36 100644
--- a/drivers/input/serio/q40kbd.c
+++ b/drivers/input/serio/q40kbd.c
@@ -39,17 +39,14 @@ struct q40kbd {
 static irqreturn_t q40kbd_interrupt(int irq, void *dev_id)
 {
 	struct q40kbd *q40kbd = dev_id;
-	unsigned long flags;
 
-	spin_lock_irqsave(&q40kbd->lock, flags);
+	guard(spinlock_irqsave)(&q40kbd->lock);
 
 	if (Q40_IRQ_KEYB_MASK & master_inb(INTERRUPT_REG))
 		serio_interrupt(q40kbd->port, master_inb(KEYCODE_REG), 0);
 
 	master_outb(-1, KEYBOARD_UNLOCK_REG);
 
-	spin_unlock_irqrestore(&q40kbd->lock, flags);
-
 	return IRQ_HANDLED;
 }
 
@@ -60,14 +57,11 @@ static irqreturn_t q40kbd_interrupt(int irq, void *dev_id)
 static void q40kbd_flush(struct q40kbd *q40kbd)
 {
 	int maxread = 100;
-	unsigned long flags;
 
-	spin_lock_irqsave(&q40kbd->lock, flags);
+	guard(spinlock_irqsave)(&q40kbd->lock);
 
 	while (maxread-- && (Q40_IRQ_KEYB_MASK & master_inb(INTERRUPT_REG)))
 		master_inb(KEYCODE_REG);
-
-	spin_unlock_irqrestore(&q40kbd->lock, flags);
 }
 
 static void q40kbd_stop(void)
-- 
2.51.0


From d8ea63cb4475f1e7ac2979d7181e2b9114c7f5b2 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:22 -0700
Subject: [PATCH 14/16] Input: sa1111ps2 - use guard notation when acquiring
 spinlock

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

Link: https://lore.kernel.org/r/20240905041732.2034348-18-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/serio/sa1111ps2.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/input/serio/sa1111ps2.c b/drivers/input/serio/sa1111ps2.c
index 1311caf7dba4..375c6f5f905c 100644
--- a/drivers/input/serio/sa1111ps2.c
+++ b/drivers/input/serio/sa1111ps2.c
@@ -92,7 +92,8 @@ static irqreturn_t ps2_txint(int irq, void *dev_id)
 	struct ps2if *ps2if = dev_id;
 	unsigned int status;
 
-	spin_lock(&ps2if->lock);
+	guard(spinlock)(&ps2if->lock);
+
 	status = readl_relaxed(ps2if->base + PS2STAT);
 	if (ps2if->head == ps2if->tail) {
 		disable_irq_nosync(irq);
@@ -101,7 +102,6 @@ static irqreturn_t ps2_txint(int irq, void *dev_id)
 		writel_relaxed(ps2if->buf[ps2if->tail], ps2if->base + PS2DATA);
 		ps2if->tail = (ps2if->tail + 1) & (sizeof(ps2if->buf) - 1);
 	}
-	spin_unlock(&ps2if->lock);
 
 	return IRQ_HANDLED;
 }
@@ -113,10 +113,9 @@ static irqreturn_t ps2_txint(int irq, void *dev_id)
 static int ps2_write(struct serio *io, unsigned char val)
 {
 	struct ps2if *ps2if = io->port_data;
-	unsigned long flags;
 	unsigned int head;
 
-	spin_lock_irqsave(&ps2if->lock, flags);
+	guard(spinlock_irqsave)(&ps2if->lock);
 
 	/*
 	 * If the TX register is empty, we can go straight out.
@@ -133,7 +132,6 @@ static int ps2_write(struct serio *io, unsigned char val)
 		}
 	}
 
-	spin_unlock_irqrestore(&ps2if->lock, flags);
 	return 0;
 }
 
-- 
2.51.0


From f7d15dcc249e54aedcfc71dddb6418b0bb2b8531 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:23 -0700
Subject: [PATCH 15/16] Input: serport - use guard notation when acquiring
 spinlock

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

Link: https://lore.kernel.org/r/20240905041732.2034348-19-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/serio/serport.c | 27 ++++++++-------------------
 1 file changed, 8 insertions(+), 19 deletions(-)

diff --git a/drivers/input/serio/serport.c b/drivers/input/serio/serport.c
index 5a2b5404ffc2..74ac88796187 100644
--- a/drivers/input/serio/serport.c
+++ b/drivers/input/serio/serport.c
@@ -50,11 +50,9 @@ static int serport_serio_write(struct serio *serio, unsigned char data)
 static int serport_serio_open(struct serio *serio)
 {
 	struct serport *serport = serio->port_data;
-	unsigned long flags;
 
-	spin_lock_irqsave(&serport->lock, flags);
+	guard(spinlock_irqsave)(&serport->lock);
 	set_bit(SERPORT_ACTIVE, &serport->flags);
-	spin_unlock_irqrestore(&serport->lock, flags);
 
 	return 0;
 }
@@ -63,11 +61,9 @@ static int serport_serio_open(struct serio *serio)
 static void serport_serio_close(struct serio *serio)
 {
 	struct serport *serport = serio->port_data;
-	unsigned long flags;
 
-	spin_lock_irqsave(&serport->lock, flags);
+	guard(spinlock_irqsave)(&serport->lock);
 	clear_bit(SERPORT_ACTIVE, &serport->flags);
-	spin_unlock_irqrestore(&serport->lock, flags);
 }
 
 /*
@@ -118,14 +114,13 @@ static void serport_ldisc_receive(struct tty_struct *tty, const u8 *cp,
 				  const u8 *fp, size_t count)
 {
 	struct serport *serport = tty->disc_data;
-	unsigned long flags;
 	unsigned int ch_flags = 0;
 	int i;
 
-	spin_lock_irqsave(&serport->lock, flags);
+	guard(spinlock_irqsave)(&serport->lock);
 
 	if (!test_bit(SERPORT_ACTIVE, &serport->flags))
-		goto out;
+		return;
 
 	for (i = 0; i < count; i++) {
 		if (fp) {
@@ -146,9 +141,6 @@ static void serport_ldisc_receive(struct tty_struct *tty, const u8 *cp,
 
 		serio_interrupt(serport->serio, cp[i], ch_flags);
 	}
-
-out:
-	spin_unlock_irqrestore(&serport->lock, flags);
 }
 
 /*
@@ -246,11 +238,9 @@ static int serport_ldisc_compat_ioctl(struct tty_struct *tty,
 static void serport_ldisc_hangup(struct tty_struct *tty)
 {
 	struct serport *serport = tty->disc_data;
-	unsigned long flags;
 
-	spin_lock_irqsave(&serport->lock, flags);
-	set_bit(SERPORT_DEAD, &serport->flags);
-	spin_unlock_irqrestore(&serport->lock, flags);
+	scoped_guard(spinlock_irqsave, &serport->lock)
+		set_bit(SERPORT_DEAD, &serport->flags);
 
 	wake_up_interruptible(&serport->wait);
 }
@@ -258,12 +248,11 @@ static void serport_ldisc_hangup(struct tty_struct *tty)
 static void serport_ldisc_write_wakeup(struct tty_struct * tty)
 {
 	struct serport *serport = tty->disc_data;
-	unsigned long flags;
 
-	spin_lock_irqsave(&serport->lock, flags);
+	guard(spinlock_irqsave)(&serport->lock);
+
 	if (test_bit(SERPORT_ACTIVE, &serport->flags))
 		serio_drv_write_wakeup(serport->serio);
-	spin_unlock_irqrestore(&serport->lock, flags);
 }
 
 /*
-- 
2.51.0


From 924c5eeb17490136d9ec688b0926bbae27eb0a1f Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Wed, 4 Sep 2024 21:17:24 -0700
Subject: [PATCH 16/16] Input: serio - use guard notation when acquiring
 mutexes and spinlocks

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

Link: https://lore.kernel.org/r/20240905041732.2034348-20-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/serio/serio.c | 165 +++++++++++++++---------------------
 1 file changed, 66 insertions(+), 99 deletions(-)

diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
index 97d8eacb9112..4468018cef66 100644
--- a/drivers/input/serio/serio.c
+++ b/drivers/input/serio/serio.c
@@ -38,33 +38,27 @@ static void serio_attach_driver(struct serio_driver *drv);
 
 static int serio_connect_driver(struct serio *serio, struct serio_driver *drv)
 {
-	int retval;
-
-	mutex_lock(&serio->drv_mutex);
-	retval = drv->connect(serio, drv);
-	mutex_unlock(&serio->drv_mutex);
+	guard(mutex)(&serio->drv_mutex);
 
-	return retval;
+	return drv->connect(serio, drv);
 }
 
 static int serio_reconnect_driver(struct serio *serio)
 {
-	int retval = -1;
+	guard(mutex)(&serio->drv_mutex);
 
-	mutex_lock(&serio->drv_mutex);
 	if (serio->drv && serio->drv->reconnect)
-		retval = serio->drv->reconnect(serio);
-	mutex_unlock(&serio->drv_mutex);
+		return serio->drv->reconnect(serio);
 
-	return retval;
+	return -1;
 }
 
 static void serio_disconnect_driver(struct serio *serio)
 {
-	mutex_lock(&serio->drv_mutex);
+	guard(mutex)(&serio->drv_mutex);
+
 	if (serio->drv)
 		serio->drv->disconnect(serio);
-	mutex_unlock(&serio->drv_mutex);
 }
 
 static int serio_match_port(const struct serio_device_id *ids, struct serio *serio)
@@ -147,9 +141,8 @@ static LIST_HEAD(serio_event_list);
 static struct serio_event *serio_get_event(void)
 {
 	struct serio_event *event = NULL;
-	unsigned long flags;
 
-	spin_lock_irqsave(&serio_event_lock, flags);
+	guard(spinlock_irqsave)(&serio_event_lock);
 
 	if (!list_empty(&serio_event_list)) {
 		event = list_first_entry(&serio_event_list,
@@ -157,7 +150,6 @@ static struct serio_event *serio_get_event(void)
 		list_del_init(&event->node);
 	}
 
-	spin_unlock_irqrestore(&serio_event_lock, flags);
 	return event;
 }
 
@@ -171,9 +163,8 @@ static void serio_remove_duplicate_events(void *object,
 					  enum serio_event_type type)
 {
 	struct serio_event *e, *next;
-	unsigned long flags;
 
-	spin_lock_irqsave(&serio_event_lock, flags);
+	guard(spinlock_irqsave)(&serio_event_lock);
 
 	list_for_each_entry_safe(e, next, &serio_event_list, node) {
 		if (object == e->object) {
@@ -189,15 +180,13 @@ static void serio_remove_duplicate_events(void *object,
 			serio_free_event(e);
 		}
 	}
-
-	spin_unlock_irqrestore(&serio_event_lock, flags);
 }
 
 static void serio_handle_event(struct work_struct *work)
 {
 	struct serio_event *event;
 
-	mutex_lock(&serio_mutex);
+	guard(mutex)(&serio_mutex);
 
 	while ((event = serio_get_event())) {
 
@@ -228,8 +217,6 @@ static void serio_handle_event(struct work_struct *work)
 		serio_remove_duplicate_events(event->object, event->type);
 		serio_free_event(event);
 	}
-
-	mutex_unlock(&serio_mutex);
 }
 
 static DECLARE_WORK(serio_event_work, serio_handle_event);
@@ -237,11 +224,9 @@ static DECLARE_WORK(serio_event_work, serio_handle_event);
 static int serio_queue_event(void *object, struct module *owner,
 			     enum serio_event_type event_type)
 {
-	unsigned long flags;
 	struct serio_event *event;
-	int retval = 0;
 
-	spin_lock_irqsave(&serio_event_lock, flags);
+	guard(spinlock_irqsave)(&serio_event_lock);
 
 	/*
 	 * Scan event list for the other events for the same serio port,
@@ -253,7 +238,7 @@ static int serio_queue_event(void *object, struct module *owner,
 	list_for_each_entry_reverse(event, &serio_event_list, node) {
 		if (event->object == object) {
 			if (event->type == event_type)
-				goto out;
+				return 0;
 			break;
 		}
 	}
@@ -261,16 +246,14 @@ static int serio_queue_event(void *object, struct module *owner,
 	event = kmalloc(sizeof(*event), GFP_ATOMIC);
 	if (!event) {
 		pr_err("Not enough memory to queue event %d\n", event_type);
-		retval = -ENOMEM;
-		goto out;
+		return -ENOMEM;
 	}
 
 	if (!try_module_get(owner)) {
 		pr_warn("Can't get module reference, dropping event %d\n",
 			event_type);
 		kfree(event);
-		retval = -EINVAL;
-		goto out;
+		return -EINVAL;
 	}
 
 	event->type = event_type;
@@ -280,9 +263,7 @@ static int serio_queue_event(void *object, struct module *owner,
 	list_add_tail(&event->node, &serio_event_list);
 	queue_work(system_long_wq, &serio_event_work);
 
-out:
-	spin_unlock_irqrestore(&serio_event_lock, flags);
-	return retval;
+	return 0;
 }
 
 /*
@@ -292,9 +273,8 @@ out:
 static void serio_remove_pending_events(void *object)
 {
 	struct serio_event *event, *next;
-	unsigned long flags;
 
-	spin_lock_irqsave(&serio_event_lock, flags);
+	guard(spinlock_irqsave)(&serio_event_lock);
 
 	list_for_each_entry_safe(event, next, &serio_event_list, node) {
 		if (event->object == object) {
@@ -302,8 +282,6 @@ static void serio_remove_pending_events(void *object)
 			serio_free_event(event);
 		}
 	}
-
-	spin_unlock_irqrestore(&serio_event_lock, flags);
 }
 
 /*
@@ -315,23 +293,19 @@ static void serio_remove_pending_events(void *object)
 static struct serio *serio_get_pending_child(struct serio *parent)
 {
 	struct serio_event *event;
-	struct serio *serio, *child = NULL;
-	unsigned long flags;
+	struct serio *serio;
 
-	spin_lock_irqsave(&serio_event_lock, flags);
+	guard(spinlock_irqsave)(&serio_event_lock);
 
 	list_for_each_entry(event, &serio_event_list, node) {
 		if (event->type == SERIO_REGISTER_PORT) {
 			serio = event->object;
-			if (serio->parent == parent) {
-				child = serio;
-				break;
-			}
+			if (serio->parent == parent)
+				return serio;
 		}
 	}
 
-	spin_unlock_irqrestore(&serio_event_lock, flags);
-	return child;
+	return NULL;
 }
 
 /*
@@ -382,29 +356,27 @@ static ssize_t drvctl_store(struct device *dev, struct device_attribute *attr, c
 	struct device_driver *drv;
 	int error;
 
-	error = mutex_lock_interruptible(&serio_mutex);
-	if (error)
-		return error;
-
-	if (!strncmp(buf, "none", count)) {
-		serio_disconnect_port(serio);
-	} else if (!strncmp(buf, "reconnect", count)) {
-		serio_reconnect_subtree(serio);
-	} else if (!strncmp(buf, "rescan", count)) {
-		serio_disconnect_port(serio);
-		serio_find_driver(serio);
-		serio_remove_duplicate_events(serio, SERIO_RESCAN_PORT);
-	} else if ((drv = driver_find(buf, &serio_bus)) != NULL) {
-		serio_disconnect_port(serio);
-		error = serio_bind_driver(serio, to_serio_driver(drv));
-		serio_remove_duplicate_events(serio, SERIO_RESCAN_PORT);
-	} else {
-		error = -EINVAL;
+	scoped_cond_guard(mutex_intr, return -EINTR, &serio_mutex) {
+		if (!strncmp(buf, "none", count)) {
+			serio_disconnect_port(serio);
+		} else if (!strncmp(buf, "reconnect", count)) {
+			serio_reconnect_subtree(serio);
+		} else if (!strncmp(buf, "rescan", count)) {
+			serio_disconnect_port(serio);
+			serio_find_driver(serio);
+			serio_remove_duplicate_events(serio, SERIO_RESCAN_PORT);
+		} else if ((drv = driver_find(buf, &serio_bus)) != NULL) {
+			serio_disconnect_port(serio);
+			error = serio_bind_driver(serio, to_serio_driver(drv));
+			serio_remove_duplicate_events(serio, SERIO_RESCAN_PORT);
+			if (error)
+				return error;
+		} else {
+			return -EINVAL;
+		}
 	}
 
-	mutex_unlock(&serio_mutex);
-
-	return error ? error : count;
+	return count;
 }
 
 static ssize_t serio_show_bind_mode(struct device *dev, struct device_attribute *attr, char *buf)
@@ -526,9 +498,9 @@ static void serio_add_port(struct serio *serio)
 	int error;
 
 	if (parent) {
-		serio_pause_rx(parent);
+		guard(serio_pause_rx)(parent);
+
 		list_add_tail(&serio->child_node, &parent->children);
-		serio_continue_rx(parent);
 	}
 
 	list_add_tail(&serio->node, &serio_list);
@@ -560,9 +532,9 @@ static void serio_destroy_port(struct serio *serio)
 		serio->stop(serio);
 
 	if (serio->parent) {
-		serio_pause_rx(serio->parent);
+		guard(serio_pause_rx)(serio->parent);
+
 		list_del_init(&serio->child_node);
-		serio_continue_rx(serio->parent);
 		serio->parent = NULL;
 	}
 
@@ -701,10 +673,10 @@ EXPORT_SYMBOL(__serio_register_port);
  */
 void serio_unregister_port(struct serio *serio)
 {
-	mutex_lock(&serio_mutex);
+	guard(mutex)(&serio_mutex);
+
 	serio_disconnect_port(serio);
 	serio_destroy_port(serio);
-	mutex_unlock(&serio_mutex);
 }
 EXPORT_SYMBOL(serio_unregister_port);
 
@@ -715,12 +687,12 @@ void serio_unregister_child_port(struct serio *serio)
 {
 	struct serio *s, *next;
 
-	mutex_lock(&serio_mutex);
+	guard(mutex)(&serio_mutex);
+
 	list_for_each_entry_safe(s, next, &serio->children, child_node) {
 		serio_disconnect_port(s);
 		serio_destroy_port(s);
 	}
-	mutex_unlock(&serio_mutex);
 }
 EXPORT_SYMBOL(serio_unregister_child_port);
 
@@ -784,10 +756,10 @@ static void serio_driver_remove(struct device *dev)
 
 static void serio_cleanup(struct serio *serio)
 {
-	mutex_lock(&serio->drv_mutex);
+	guard(mutex)(&serio->drv_mutex);
+
 	if (serio->drv && serio->drv->cleanup)
 		serio->drv->cleanup(serio);
-	mutex_unlock(&serio->drv_mutex);
 }
 
 static void serio_shutdown(struct device *dev)
@@ -850,7 +822,7 @@ void serio_unregister_driver(struct serio_driver *drv)
 {
 	struct serio *serio;
 
-	mutex_lock(&serio_mutex);
+	guard(mutex)(&serio_mutex);
 
 	drv->manual_bind = true;	/* so serio_find_driver ignores it */
 	serio_remove_pending_events(drv);
@@ -866,15 +838,14 @@ start_over:
 	}
 
 	driver_unregister(&drv->driver);
-	mutex_unlock(&serio_mutex);
 }
 EXPORT_SYMBOL(serio_unregister_driver);
 
 static void serio_set_drv(struct serio *serio, struct serio_driver *drv)
 {
-	serio_pause_rx(serio);
+	guard(serio_pause_rx)(serio);
+
 	serio->drv = drv;
-	serio_continue_rx(serio);
 }
 
 static int serio_bus_match(struct device *dev, const struct device_driver *drv)
@@ -935,14 +906,14 @@ static int serio_resume(struct device *dev)
 	struct serio *serio = to_serio_port(dev);
 	int error = -ENOENT;
 
-	mutex_lock(&serio->drv_mutex);
-	if (serio->drv && serio->drv->fast_reconnect) {
-		error = serio->drv->fast_reconnect(serio);
-		if (error && error != -ENOENT)
-			dev_warn(dev, "fast reconnect failed with error %d\n",
-				 error);
+	scoped_guard(mutex, &serio->drv_mutex) {
+		if (serio->drv && serio->drv->fast_reconnect) {
+			error = serio->drv->fast_reconnect(serio);
+			if (error && error != -ENOENT)
+				dev_warn(dev, "fast reconnect failed with error %d\n",
+					 error);
+		}
 	}
-	mutex_unlock(&serio->drv_mutex);
 
 	if (error) {
 		/*
@@ -989,21 +960,17 @@ EXPORT_SYMBOL(serio_close);
 irqreturn_t serio_interrupt(struct serio *serio,
 		unsigned char data, unsigned int dfl)
 {
-	unsigned long flags;
-	irqreturn_t ret = IRQ_NONE;
+	guard(spinlock_irqsave)(&serio->lock);
 
-	spin_lock_irqsave(&serio->lock, flags);
+	if (likely(serio->drv))
+		return serio->drv->interrupt(serio, data, dfl);
 
-        if (likely(serio->drv)) {
-                ret = serio->drv->interrupt(serio, data, dfl);
-	} else if (!dfl && device_is_registered(&serio->dev)) {
+	if (!dfl && device_is_registered(&serio->dev)) {
 		serio_rescan(serio);
-		ret = IRQ_HANDLED;
+		return IRQ_HANDLED;
 	}
 
-	spin_unlock_irqrestore(&serio->lock, flags);
-
-	return ret;
+	return IRQ_NONE;
 }
 EXPORT_SYMBOL(serio_interrupt);
 
-- 
2.51.0