Hi Josef,
Smatch complains about this change introduces a double unlock.
fs/btrfs/async-thread.c +608 find_worker(49) error: double unlock 'spin_lock:&workers->lock'
579 spin_unlock_irqrestore(&workers->lock, flags);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
We unlock here.
580 /* we're below the limit, start another worker */
581 ret = __btrfs_start_workers(workers);
582 if (ret)
583 goto fallback;
584 goto again;
585 }
586 }
587 goto found;
588
589 fallback:
590 fallback = NULL;
591 /*
592 * we have failed to find any workers, just
593 * return the first one we can find.
594 */
595 if (!list_empty(&workers->worker_list))
596 fallback = workers->worker_list.next;
597 if (!list_empty(&workers->idle_list))
598 fallback = workers->idle_list.next;
599 BUG_ON(!fallback);
600 worker = list_entry(fallback,
601 struct btrfs_worker_thread, worker_list);
602 found:
603 /*
604 * this makes sure the worker doesn't exit before it is placed
605 * onto a busy/idle list
606 */
607 atomic_inc(&worker->num_pending);
608 spin_unlock_irqrestore(&workers->lock, flags);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
And again here.
Btw, does find_worker() ever get called with IRQs disabled? If so then
__btrfs_start_workers() enables them. Maybe that function should use
spin_lock_irqsave() instead of spin_lock_irq().
regards,
dan carpenter
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