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| 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/drbd/drbd_int.h | |
| parent | drbd: drbd_rs_number_requests: fix unit mismatch in comparison (diff) | |
| download | linux-15e26f6a3c6de2c665b4a30b9a70a902111f281f.tar.xz linux-15e26f6a3c6de2c665b4a30b9a70a902111f281f.zip | |
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/drbd/drbd_int.h')
| -rw-r--r-- | drivers/block/drbd/drbd_int.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index c88d6c6be70b..a71f8bb9dc80 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)) { |