spa_async_tasks
done = (spa->spa_async_thread == NULL && !spa->spa_async_tasks);
(spa_async_tasks(dp->dp_spa) & SPA_ASYNC_RESILVER));
tasks = spa->spa_async_tasks;
spa->spa_async_tasks = 0;
non_config_tasks = spa->spa_async_tasks & ~SPA_ASYNC_CONFIG_UPDATE;
config_task = spa->spa_async_tasks & SPA_ASYNC_CONFIG_UPDATE;
spa->spa_async_tasks |= task;
return (spa->spa_async_tasks);
extern int spa_async_tasks(spa_t *spa);
uint16_t spa_async_tasks; /* async task mask */