mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 11:19:37 +00:00
powerpc/pmac: Don't add_timer() twice
If the interrupt and the timeout happen roughly at the same time, we can get into a situation where the timer function is run while the interrupt has already been processed. In this case, the timer function might end up doing an add_timer on an already pending timer, causing a BUG_ON() to trigger. Instead, just skip the whole timeout operation if we see that the timer is pending. The spinlock ensures that the only way that happens is if we already started a new operation and thus the timeout can be ignored. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
parent
2ef822c553
commit
3027691e58
1 changed files with 9 additions and 0 deletions
|
@ -366,11 +366,20 @@ static void kw_i2c_timeout(unsigned long data)
|
|||
unsigned long flags;
|
||||
|
||||
spin_lock_irqsave(&host->lock, flags);
|
||||
|
||||
/*
|
||||
* If the timer is pending, that means we raced with the
|
||||
* irq, in which case we just return
|
||||
*/
|
||||
if (timer_pending(&host->timeout_timer))
|
||||
goto skip;
|
||||
|
||||
kw_i2c_handle_interrupt(host, kw_read_reg(reg_isr));
|
||||
if (host->state != state_idle) {
|
||||
host->timeout_timer.expires = jiffies + KW_POLL_TIMEOUT;
|
||||
add_timer(&host->timeout_timer);
|
||||
}
|
||||
skip:
|
||||
spin_unlock_irqrestore(&host->lock, flags);
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue