On Wed, Apr 18 2007, Jens Axboe wrote:
> I had something similar for generic_unplug_request() as well, but didn't
> see/hear any reports of it being tried out. Here's a complete debugging
> patch for this and other potential dangers.
Which had a bug (do the check _after_ deleting from the rbtree,
otherwise it'll go rightfully BUG() the first time).
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 6853fb7..9aa7bf7 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -644,12 +644,15 @@ static void cfq_remove_request(struct request *rq)
{
struct cfq_queue *cfqq = RQ_CFQQ(rq);
+ BUG_ON(!irqs_disabled());
if (cfqq->next_rq == rq)
cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq);
list_del_init(&rq->queuelist);
cfq_del_rq_rb(rq);
+ BUG_ON(!cfqq->next_rq && !RB_EMPTY_ROOT(&cfqq->sort_list));
+
if (rq_is_meta(rq)) {
WARN_ON(!cfqq->meta_pending);
cfqq->meta_pending--;
@@ -1231,6 +1234,8 @@ static void cfq_exit_single_io_context(struct
cfq_io_context *cic)
{
struct cfq_data *cfqd = cic->key;
+ BUG_ON(irqs_disabled());
+
if (cfqd) {
request_queue_t *q = cfqd->queue;
@@ -1699,6 +1704,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue
*cfqq,
/*
* check if this request is a better next-serve candidate)) {
*/
+ BUG_ON(!irqs_disabled());
cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
BUG_ON(!cfqq->next_rq);
@@ -2014,6 +2020,7 @@ static void cfq_exit_queue(elevator_t *e)
cfq_shutdown_timer_wq(cfqd);
+ BUG_ON(irqs_disabled());
spin_lock_irq(q->queue_lock);
if (cfqd->active_queue)
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 3de0695..c16863e 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -1602,6 +1602,8 @@ EXPORT_SYMBOL(__generic_unplug_device);
**/
void generic_unplug_device(request_queue_t *q)
{
+ BUG_ON(irqs_disabled());
+
spin_lock_irq(q->queue_lock);
__generic_unplug_device(q);
spin_unlock_irq(q->queue_lock);
--
Jens Axboe
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
