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Subject[PATCH] Misc mISDN timerdev fixes
Hi Karsten,

For some reason i looked at the mISDN timerdev code and noticed
some minor issues (which I fixed) and a major one (which I only
commented). The major one is a SMP timer race. I think it needs
reference counting on the timer object to fix properly.

-Andi

--

Misc mISDN timerdev fixes

- Remove noop VFS stubs. The VFS does that on a NULL pointer anyways.
- Fix timer handler prototype to be correct
- Comment ugly SMP race I didn't fix.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

Index: linux-2.6.27-rc4-misc/drivers/isdn/mISDN/timerdev.c
===================================================================
--- linux-2.6.27-rc4-misc.orig/drivers/isdn/mISDN/timerdev.c
+++ linux-2.6.27-rc4-misc/drivers/isdn/mISDN/timerdev.c
@@ -124,18 +124,6 @@ mISDN_read(struct file *filep, char *buf
return ret;
}

-static loff_t
-mISDN_llseek(struct file *filep, loff_t offset, int orig)
-{
- return -ESPIPE;
-}
-
-static ssize_t
-mISDN_write(struct file *filep, const char *buf, size_t count, loff_t *off)
-{
- return -EOPNOTSUPP;
-}
-
static unsigned int
mISDN_poll(struct file *filep, poll_table *wait)
{
@@ -157,8 +145,9 @@ mISDN_poll(struct file *filep, poll_tabl
}

static void
-dev_expire_timer(struct mISDNtimer *timer)
+dev_expire_timer(unsigned long data)
{
+ struct mISDNtimer *timer = (void *)data;
u_long flags;

spin_lock_irqsave(&timer->dev->lock, flags);
@@ -191,7 +180,7 @@ misdn_add_timer(struct mISDNtimerdev *de
spin_unlock_irqrestore(&dev->lock, flags);
timer->dev = dev;
timer->tl.data = (long)timer;
- timer->tl.function = (void *) dev_expire_timer;
+ timer->tl.function = dev_expire_timer;
init_timer(&timer->tl);
timer->tl.expires = jiffies + ((HZ * (u_long)timeout) / 1000);
add_timer(&timer->tl);
@@ -211,6 +200,9 @@ misdn_del_timer(struct mISDNtimerdev *de
list_for_each_entry(timer, &dev->pending, list) {
if (timer->id == id) {
list_del_init(&timer->list);
+ /* RED-PEN AK: race -- timer can be still running on
+ * other CPU. Needs reference count I think
+ */
del_timer(&timer->tl);
ret = timer->id;
kfree(timer);
@@ -268,9 +260,7 @@ mISDN_ioctl(struct inode *inode, struct
}

static struct file_operations mISDN_fops = {
- .llseek = mISDN_llseek,
.read = mISDN_read,
- .write = mISDN_write,
.poll = mISDN_poll,
.ioctl = mISDN_ioctl,
.open = mISDN_open,

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