diff options
Diffstat (limited to 'kernel/watch_queue.c')
| -rw-r--r-- | kernel/watch_queue.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/kernel/watch_queue.c b/kernel/watch_queue.c index 538520861e8b..932a88ac1f39 100644 --- a/kernel/watch_queue.c +++ b/kernel/watch_queue.c @@ -101,7 +101,7 @@ static bool post_one_notification(struct watch_queue *wqueue, struct pipe_inode_info *pipe = wqueue->pipe; struct pipe_buffer *buf; struct page *page; - unsigned int head, tail, note, offset, len; + unsigned int head, tail, note, offset, len, nr_notes; bool done = false; spin_lock_irq(&pipe->rd_wait.lock); @@ -111,8 +111,10 @@ static bool post_one_notification(struct watch_queue *wqueue, if (pipe_full(head, tail, pipe->ring_size)) goto lost; - note = find_first_bit(wqueue->notes_bitmap, wqueue->nr_notes); - if (note >= wqueue->nr_notes) + /* Pairs with the smp_store_release() in watch_queue_set_size(). */ + nr_notes = smp_load_acquire(&wqueue->nr_notes); + note = find_first_bit(wqueue->notes_bitmap, nr_notes); + if (note >= nr_notes) goto lost; page = wqueue->notes[note / WATCH_QUEUE_NOTES_PER_PAGE]; @@ -297,7 +299,8 @@ long watch_queue_set_size(struct pipe_inode_info *pipe, unsigned int nr_notes) wqueue->notes = pages; wqueue->notes_bitmap = bitmap; wqueue->nr_pages = nr_pages; - wqueue->nr_notes = nr_notes; + /* Pairs with the smp_load_acquire() in post_one_notification(). */ + smp_store_release(&wqueue->nr_notes, nr_notes); return 0; error_p: |