From 23450319e2890986c247ec0aa1442f060e657e6d Mon Sep 17 00:00:00 2001 From: Suleiman Souhlal Date: Tue, 10 Apr 2007 22:38:37 +0200 Subject: ide: correctly prevent IDE timer expiry function to run if request was already handled It is possible for the timer expiry function to run even though the request has already been handled: ide_timer_expiry() only checks that the handler is not NULL, but it is possible that we have handled a request (thus clearing the handler) and then started a new request (thus starting the timer again, and setting a handler). A simple way to exhibit this is to set the DMA timeout to 1 jiffy and run dd: The kernel will panic after a few minutes because ide_timer_expiry() tries to add a timer when it's already active. To fix this, we simply add a request generation count that gets incremented at every interrupt, and check in ide_timer_expiry() that we have not already handled a new interrupt before running the expiry function. Signed-off-by: Suleiman Souhlal Signed-off-by: Bartlomiej Zolnierkiewicz --- drivers/ide/ide-io.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/ide/ide-io.c') diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c index 0e02800..8670112 100644 --- a/drivers/ide/ide-io.c +++ b/drivers/ide/ide-io.c @@ -1226,6 +1226,7 @@ static void ide_do_request (ide_hwgroup_t *hwgroup, int masked_irq) #endif /* so that ide_timer_expiry knows what to do */ hwgroup->sleeping = 1; + hwgroup->req_gen_timer = hwgroup->req_gen; mod_timer(&hwgroup->timer, sleep); /* we purposely leave hwgroup->busy==1 * while sleeping */ @@ -1411,7 +1412,8 @@ void ide_timer_expiry (unsigned long data) spin_lock_irqsave(&ide_lock, flags); - if ((handler = hwgroup->handler) == NULL) { + if (((handler = hwgroup->handler) == NULL) || + (hwgroup->req_gen != hwgroup->req_gen_timer)) { /* * Either a marginal timeout occurred * (got the interrupt just as timer expired), @@ -1439,6 +1441,7 @@ void ide_timer_expiry (unsigned long data) if ((wait = expiry(drive)) > 0) { /* reset timer */ hwgroup->timer.expires = jiffies + wait; + hwgroup->req_gen_timer = hwgroup->req_gen; add_timer(&hwgroup->timer); spin_unlock_irqrestore(&ide_lock, flags); return; @@ -1653,6 +1656,7 @@ irqreturn_t ide_intr (int irq, void *dev_id) printk(KERN_ERR "%s: ide_intr: hwgroup->busy was 0 ??\n", drive->name); } hwgroup->handler = NULL; + hwgroup->req_gen++; del_timer(&hwgroup->timer); spin_unlock(&ide_lock); -- cgit v1.1