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/[email protected]
Signed-off-by: Dmitry Torokhov <[email protected]>

Author: dtor

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