Input: add serio_pause_rx and serio_continue_rx so drivers can protect

       their critical sections from port's interrupt handler
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/serio/serio.c

@@ -541,15 +541,14 @@ void serio_unregister_driver(struct serio_driver *drv)
 /* called from serio_driver->connect/disconnect methods under serio_sem */
 int serio_open(struct serio *serio, struct serio_driver *drv)
 {
-	unsigned long flags;
-
-	spin_lock_irqsave(&serio->lock, flags);
+	serio_pause_rx(serio);
 	serio->drv = drv;
-	spin_unlock_irqrestore(&serio->lock, flags);
+	serio_continue_rx(serio);
+
 	if (serio->open && serio->open(serio)) {
-		spin_lock_irqsave(&serio->lock, flags);
+		serio_pause_rx(serio);
 		serio->drv = NULL;
-		spin_unlock_irqrestore(&serio->lock, flags);
+		serio_continue_rx(serio);
 		return -1;
 	}
 	return 0;
@@ -558,13 +557,12 @@ int serio_open(struct serio *serio, struct serio_driver *drv)
 /* called from serio_driver->connect/disconnect methods under serio_sem */
 void serio_close(struct serio *serio)
 {
-	unsigned long flags;
-
 	if (serio->close)
 		serio->close(serio);
-	spin_lock_irqsave(&serio->lock, flags);
+
+	serio_pause_rx(serio);
 	serio->drv = NULL;
-	spin_unlock_irqrestore(&serio->lock, flags);
+	serio_continue_rx(serio);
 }
 
 irqreturn_t serio_interrupt(struct serio *serio,

include/linux/serio.h

@@ -35,7 +35,7 @@ struct serio {
 	unsigned long type;
 	unsigned long event;
 
-	spinlock_t lock;
+	spinlock_t lock;		/* protects critical sections from port's interrupt handler */
 
 	int (*write)(struct serio *, unsigned char);
 	int (*open)(struct serio *);
@@ -43,7 +43,7 @@ struct serio {
 
 	struct serio *parent, *child;
 
-	struct serio_driver *drv; /* Accessed from interrupt, writes must be protected by serio_lock */
+	struct serio_driver *drv;	/* accessed from interrupt, must be protected by serio->lock */
 
 	struct device dev;
 
@@ -81,6 +81,7 @@ void serio_register_port(struct serio *serio);
 void serio_register_port_delayed(struct serio *serio);
 void serio_unregister_port(struct serio *serio);
 void serio_unregister_port_delayed(struct serio *serio);
+
 void serio_register_driver(struct serio_driver *drv);
 void serio_unregister_driver(struct serio_driver *drv);
 
@@ -104,6 +105,22 @@ static __inline__ void serio_cleanup(struct serio *serio)
 		serio->drv->cleanup(serio);
 }
 
+
+/*
+ * Use the following fucntions to protect critical sections in
+ * driver code from port's interrupt handler
+ */
+static __inline__ void serio_pause_rx(struct serio *serio)
+{
+	spin_lock_irq(&serio->lock);
+}
+
+static __inline__ void serio_continue_rx(struct serio *serio)
+{
+	spin_unlock_irq(&serio->lock);
+}
+
+
 #endif
 
 /*