Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 15e26f6a authored by Lars Ellenberg's avatar Lars Ellenberg Committed by Philipp Reisner
Browse files

drbd: add drbd_queue_work_if_unqueued helper 



We sometimes do
    if (list_empty(&w.list))
	drbd_queue_work(&q, &w.list);

Removal (list_del_init) may happen outside all locks, after all
pending work entries have been moved to an on-stack local work list.

For not dynamically allocated, but embeded, work structs,
we must avoid to re-add until it really was removed.

Move that list_empty check inside the spin_lock(&q->q_lock)
within the helper function, and change to list_empty_careful().

This may have been the reason for a list_add corruption
inside drbd_queue_work().

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent 7f34f614

drivers/block/drbd/drbd_int.h

+11 −0
Original line number Diff line number Diff line
@@ -1777,6 +1777,17 @@ drbd_queue_work(struct drbd_work_queue *q, struct drbd_work *w) 
	wake_up(&q->q_wait);

}



static inline void

drbd_queue_work_if_unqueued(struct drbd_work_queue *q, struct drbd_work *w)

{

	unsigned long flags;

	spin_lock_irqsave(&q->q_lock, flags);

	if (list_empty_careful(&w->list))

		list_add_tail(&w->list, &q->q);

	spin_unlock_irqrestore(&q->q_lock, flags);

	wake_up(&q->q_wait);

}



static inline void

drbd_device_post_work(struct drbd_device *device, int work_bit)

{

drivers/block/drbd/drbd_worker.c

+4 −4
Original line number Diff line number Diff line
@@ -452,8 +452,8 @@ void resync_timer_fn(unsigned long data) 
{

	struct drbd_device *device = (struct drbd_device *) data;



	if (list_empty(&device->resync_work.list))

		drbd_queue_work(&first_peer_device(device)->connection->sender_work,

	drbd_queue_work_if_unqueued(

		&first_peer_device(device)->connection->sender_work,

		&device->resync_work);

}
@@ -1968,7 +1968,7 @@ static void do_unqueued_work(struct drbd_connection *connection) 
static bool dequeue_work_batch(struct drbd_work_queue *queue, struct list_head *work_list)

{

	spin_lock_irq(&queue->q_lock);

	list_splice_init(&queue->q, work_list);

	list_splice_tail_init(&queue->q, work_list);

	spin_unlock_irq(&queue->q_lock);

	return !list_empty(work_list);

}