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Commit 4e8d340d authored by Dmitry Torokhov's avatar Dmitry Torokhov
Browse files

Input: i8042 - fix locking in interrupt routine 



We need to protect not only i8042 status and data register from concurrent
access from IRQ 1 and 12 but the rest of the shared state as well, so let's
move release of i8042_lock in i8042_interrupt() a little bit further down.

Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 7105d2ea

drivers/input/serio/i8042.c

+26 −8
Original line number Diff line number Diff line
@@ -368,6 +368,25 @@ static void i8042_stop(struct serio *serio) 
	port->serio = NULL;

}



/*

 * i8042_filter() filters out unwanted bytes from the input data stream.

 * It is called from i8042_interrupt and thus is running with interrupts

 * off and i8042_lock held.

 */

static bool i8042_filter(unsigned char data, unsigned char str)

{

	if (unlikely(i8042_suppress_kbd_ack)) {

		if ((~str & I8042_STR_AUXDATA) &&

		    (data == 0xfa || data == 0xfe)) {

			i8042_suppress_kbd_ack--;

			dbg("Extra keyboard ACK - filtered out\n");

			return true;

		}

	}



	return false;

}



/*

 * i8042_interrupt() is the most important function in this driver -

 * it handles the interrupts from the i8042, and sends incoming bytes
@@ -381,9 +400,11 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id) 
	unsigned char str, data;

	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);
@@ -391,8 +412,8 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id) 
		ret = 0;

		goto out;

	}



	data = i8042_read_data();

	spin_unlock_irqrestore(&i8042_lock, flags);



	if (i8042_mux_present && (str & I8042_STR_AUXDATA)) {

		static unsigned long last_transmit;
@@ -447,14 +468,11 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id) 
	    dfl & SERIO_PARITY ? ", bad parity" : "",

	    dfl & SERIO_TIMEOUT ? ", timeout" : "");



	if (unlikely(i8042_suppress_kbd_ack))

		if (port_no == I8042_KBD_PORT_NO &&

		    (data == 0xfa || data == 0xfe)) {

			i8042_suppress_kbd_ack--;

			goto out;

		}

	filtered = i8042_filter(data, str);



	spin_unlock_irqrestore(&i8042_lock, flags);



	if (likely(port->exists))

	if (likely(port->exists && !filtered))

		serio_interrupt(port->serio, data, dfl);



 out: