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Subject[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: Mark Gross <mark.gross@intel.com>

thanks,

--mgross

diff -urN -X linux-2.6.20-rc2-mm1/Documentation/dontdiff linux-2.6.20-rc2-mm1/drivers/char/tlclk.c linux-2.6.20-rc2-mm1-tlclk/drivers/char/tlclk.c
--- linux-2.6.20-rc2-mm1/drivers/char/tlclk.c 2007-01-03 08:46:18.000000000 -0800
+++ linux-2.6.20-rc2-mm1-tlclk/drivers/char/tlclk.c 2007-01-11 13:37:30.000000000 -0800
@@ -186,6 +186,7 @@
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 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_release(struct inode *inode, struct file *filp)
{
free_irq(telclk_interrupt, tlclk_interrupt);
+ useflags &= ~0x1;

return 0;
}
@@ -230,26 +241,25 @@
{
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 @@
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 @@
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 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 @@

/* 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);
-
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