diff options
| author | Lars Ellenberg <lars.ellenberg@linbit.com> | 2014-04-28 11:43:21 +0200 |
|---|---|---|
| committer | Philipp Reisner <philipp.reisner@linbit.com> | 2014-07-10 18:35:07 +0200 |
| commit | 15e26f6a3c6de2c665b4a30b9a70a902111f281f (patch) | |
| tree | d8050e5998e46e3f6f541b3941dd727714ae07ba /drivers/block | |
| parent | 7f34f61490ee87a470cf229069d59b0987f42a59 (diff) | |
| download | linux-0-day-15e26f6a3c6de2c665b4a30b9a70a902111f281f.tar.gz linux-0-day-15e26f6a3c6de2c665b4a30b9a70a902111f281f.tar.xz | |
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: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/drbd/drbd_int.h | 11 | ||||
| -rw-r--r-- | drivers/block/drbd/drbd_worker.c | 8 |
2 files changed, 15 insertions, 4 deletions
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index c88d6c6be70bb..a71f8bb9dc803 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -1778,6 +1778,17 @@ drbd_queue_work(struct drbd_work_queue *q, struct drbd_work *w) } 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) { if (!test_and_set_bit(work_bit, &device->flags)) { diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c index 9f0acb011f308..49b88731b349e 100644 --- a/drivers/block/drbd/drbd_worker.c +++ b/drivers/block/drbd/drbd_worker.c @@ -452,9 +452,9 @@ 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, - &device->resync_work); + drbd_queue_work_if_unqueued( + &first_peer_device(device)->connection->sender_work, + &device->resync_work); } static void fifo_set(struct fifo_buffer *fb, int value) @@ -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); } |