On Thu, Oct 11 2007, malahal@xxxxxxxxxx wrote:
> > @@ -3600,24 +3618,132 @@ static struct notifier_block __devinitdata blk_cpu_notifier = {
> > };
> >
> > /**
> > - * blk_complete_request - end I/O on a request
> > - * @req: the request being processed
> > + * blk_delete_timer - Delete/cancel timer for a given function.
> > + * @req: request that we are canceling timer for
> > *
> > - * Description:
> > - * Ends all I/O on a request. It does not handle partial completions,
> > - * unless the driver actually implements this in its completion callback
> > - * through requeueing. Theh actual completion happens out-of-order,
> > - * through a softirq handler. The user must have registered a completion
> > - * callback through blk_queue_softirq_done().
> > - **/
> > + * Return value:
> > + * 1 if we were able to detach the timer. 0 if we blew it, and the
> > + * timer function has already started to run.
> > + */
> > +int blk_delete_timer(struct request *req)
> > +{
> > + if (!req->q->rq_timed_out_fn)
> > + return 1;
> >
> > -void blk_complete_request(struct request *req)
> > + if (!list_empty(&req->timeout_list)) {
>
> This could race with timeout handler. In other words, this routine may
> return 1 while blk_rq_timed_out() is running on the request.
My current code is fine, it deletes the request from the list before
calling blk_rq_timed_out().
> > + ret = q->rq_timed_out_fn(req);
> > + switch (ret) {
> > + case BLK_EH_HANDLED:
> > + __blk_complete_request(req);
> > + break;
> > + case BLK_EH_RESET_TIMER:
> > + blk_add_timer(req);
>
> You will need to delete the req from the timeout_list before calling
> blk_add_timer again. You may need to remove the req from the list in
> other cases too.
Yep, that is exactly what I did.
--
Jens Axboe
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