Re: [PATCH] Correctly prevent IDE timer expiry function to run if request was already handled

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

On Friday 06 April 2007, Suleiman Souhlal wrote:
> 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 <suleiman@google.com>

applied, thanks for fixing this