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Commit 79603a35 authored by Mark Gross's avatar Mark Gross Committed by Linus Torvalds
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[PATCH] tlclk: bug fix + misc fixes 



The following patch fixes a few problems with the tlclk driver.
* bug in the select_amcb1_transmit_clock
* racy read sys call
* racy open sys call
* use of add_timer where mod_timer would be better
* change to the timer data parameter use

Signed-off-by: default avatarMark Gross <mark.gross@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent cda9205d

drivers/char/tlclk.c

+28 −15
Original line number Diff line number Diff line
@@ -186,6 +186,7 @@ static int got_event; /* if events processing have been done */ 
static void switchover_timeout(unsigned long data);

static struct timer_list switchover_timer =

	TIMER_INITIALIZER(switchover_timeout , 0, 0);

static unsigned long tlclk_timer_data;



static struct tlclk_alarms *alarm_events;
@@ -197,10 +198,19 @@ static irqreturn_t tlclk_interrupt(int irq, void *dev_id); 


static DECLARE_WAIT_QUEUE_HEAD(wq);



static unsigned long useflags;

static DEFINE_MUTEX(tlclk_mutex);



static int tlclk_open(struct inode *inode, struct file *filp)

{

	int result;



	if (test_and_set_bit(0, &useflags))

		return -EBUSY;

		/* this legacy device is always one per system and it doesn't

		 * know how to handle multiple concurrent clients.

		 */



	/* Make sure there is no interrupt pending while

	 * initialising interrupt handler */

	inb(TLCLK_REG6);
@@ -221,6 +231,7 @@ static int tlclk_open(struct inode *inode, struct file *filp) 
static int tlclk_release(struct inode *inode, struct file *filp)

{

	free_irq(telclk_interrupt, tlclk_interrupt);

	clear_bit(0, &useflags);



	return 0;

}
@@ -230,26 +241,25 @@ static ssize_t tlclk_read(struct file *filp, char __user *buf, size_t count, 
{

	if (count < sizeof(struct tlclk_alarms))

		return -EIO;

	if (mutex_lock_interruptible(&tlclk_mutex))

		return -EINTR;





	wait_event_interruptible(wq, got_event);

	if (copy_to_user(buf, alarm_events, sizeof(struct tlclk_alarms)))

	if (copy_to_user(buf, alarm_events, sizeof(struct tlclk_alarms))) {

		mutex_unlock(&tlclk_mutex);

		return -EFAULT;

	}



	memset(alarm_events, 0, sizeof(struct tlclk_alarms));

	got_event = 0;



	mutex_unlock(&tlclk_mutex);

	return  sizeof(struct tlclk_alarms);

}



static ssize_t tlclk_write(struct file *filp, const char __user *buf, size_t count,

	    loff_t *f_pos)

{

	return 0;

}



static const struct file_operations tlclk_fops = {

	.read = tlclk_read,

	.write = tlclk_write,

	.open = tlclk_open,

	.release = tlclk_release,
@@ -540,7 +550,7 @@ static ssize_t store_select_amcb1_transmit_clock(struct device *d, 
			SET_PORT_BITS(TLCLK_REG3, 0xf8, 0x7);

			switch (val) {

			case CLK_8_592MHz:

				SET_PORT_BITS(TLCLK_REG0, 0xfc, 1);

				SET_PORT_BITS(TLCLK_REG0, 0xfc, 2);

				break;

			case CLK_11_184MHz:

				SET_PORT_BITS(TLCLK_REG0, 0xfc, 0);
@@ -549,7 +559,7 @@ static ssize_t store_select_amcb1_transmit_clock(struct device *d, 
				SET_PORT_BITS(TLCLK_REG0, 0xfc, 3);

				break;

			case CLK_44_736MHz:

				SET_PORT_BITS(TLCLK_REG0, 0xfc, 2);

				SET_PORT_BITS(TLCLK_REG0, 0xfc, 1);

				break;

			}

		} else
@@ -839,11 +849,13 @@ static void __exit tlclk_cleanup(void) 


static void switchover_timeout(unsigned long data)

{

	if ((data & 1)) {

		if ((inb(TLCLK_REG1) & 0x08) != (data & 0x08))

	unsigned long flags = *(unsigned long *) data;



	if ((flags & 1)) {

		if ((inb(TLCLK_REG1) & 0x08) != (flags & 0x08))

			alarm_events->switchover_primary++;

	} else {

		if ((inb(TLCLK_REG1) & 0x08) != (data & 0x08))

		if ((inb(TLCLK_REG1) & 0x08) != (flags & 0x08))

			alarm_events->switchover_secondary++;

	}
@@ -901,8 +913,9 @@ static irqreturn_t tlclk_interrupt(int irq, void *dev_id) 


		/* TIMEOUT in ~10ms */

		switchover_timer.expires = jiffies + msecs_to_jiffies(10);

		switchover_timer.data = inb(TLCLK_REG1);

		add_timer(&switchover_timer);

		tlclk_timer_data = inb(TLCLK_REG1);

		switchover_timer.data = (unsigned long) &tlclk_timer_data;

		mod_timer(&switchover_timer, switchover_timer.expires);

	} else {

		got_event = 1;

		wake_up(&wq);