dm snapshot: allocate a per-target structure for snapshot-origin target

[linux-2.6-block.git] / kernel / workqueue.c

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 82ef9f3b7473a81ef5004362c7281ae9f4aea82a..8edc87185427cb17fa02ed93498fcf6f8301cb7e 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -516,6 +516,13 @@ void destroy_work_on_stack(struct work_struct *work)
 }
 EXPORT_SYMBOL_GPL(destroy_work_on_stack);
 
+void destroy_delayed_work_on_stack(struct delayed_work *work)
+{
+       destroy_timer_on_stack(&work->timer);
+       debug_object_free(&work->work, &work_debug_descr);
+}
+EXPORT_SYMBOL_GPL(destroy_delayed_work_on_stack);
+
 #else
 static inline void debug_work_activate(struct work_struct *work) { }
 static inline void debug_work_deactivate(struct work_struct *work) { }
@@ -1851,6 +1858,12 @@ static void destroy_worker(struct worker *worker)
        if (worker->flags & WORKER_IDLE)
                pool->nr_idle--;
 
+       /*
+        * Once WORKER_DIE is set, the kworker may destroy itself at any
+        * point.  Pin to ensure the task stays until we're done with it.
+        */
+       get_task_struct(worker->task);
+
        list_del_init(&worker->entry);
        worker->flags |= WORKER_DIE;
 
@@ -1859,6 +1872,7 @@ static void destroy_worker(struct worker *worker)
        spin_unlock_irq(&pool->lock);
 
        kthread_stop(worker->task);
+       put_task_struct(worker->task);
        kfree(worker);
 
        spin_lock_irq(&pool->lock);
@@ -1902,6 +1916,12 @@ static void send_mayday(struct work_struct *work)
 
        /* mayday mayday mayday */
        if (list_empty(&pwq->mayday_node)) {
+               /*
+                * If @pwq is for an unbound wq, its base ref may be put at
+                * any time due to an attribute change.  Pin @pwq until the
+                * rescuer is done with it.
+                */
+               get_pwq(pwq);
                list_add_tail(&pwq->mayday_node, &wq->maydays);
                wake_up_process(wq->rescuer->task);
        }
@@ -2384,6 +2404,7 @@ static int rescuer_thread(void *__rescuer)
        struct worker *rescuer = __rescuer;
        struct workqueue_struct *wq = rescuer->rescue_wq;
        struct list_head *scheduled = &rescuer->scheduled;
+       bool should_stop;
 
        set_user_nice(current, RESCUER_NICE_LEVEL);
 
@@ -2395,11 +2416,15 @@ static int rescuer_thread(void *__rescuer)
 repeat:
        set_current_state(TASK_INTERRUPTIBLE);
 
-       if (kthread_should_stop()) {
-               __set_current_state(TASK_RUNNING);
-               rescuer->task->flags &= ~PF_WQ_WORKER;
-               return 0;
-       }
+       /*
+        * By the time the rescuer is requested to stop, the workqueue
+        * shouldn't have any work pending, but @wq->maydays may still have
+        * pwq(s) queued.  This can happen by non-rescuer workers consuming
+        * all the work items before the rescuer got to them.  Go through
+        * @wq->maydays processing before acting on should_stop so that the
+        * list is always empty on exit.
+        */
+       should_stop = kthread_should_stop();
 
        /* see whether any pwq is asking for help */
        spin_lock_irq(&wq_mayday_lock);
@@ -2430,6 +2455,12 @@ repeat:
 
                process_scheduled_works(rescuer);
 
+               /*
+                * Put the reference grabbed by send_mayday().  @pool won't
+                * go away while we're holding its lock.
+                */
+               put_pwq(pwq);
+
                /*
                 * Leave this pool.  If keep_working() is %true, notify a
                 * regular worker; otherwise, we end up with 0 concurrency
@@ -2445,6 +2476,12 @@ repeat:
 
        spin_unlock_irq(&wq_mayday_lock);
 
+       if (should_stop) {
+               __set_current_state(TASK_RUNNING);
+               rescuer->task->flags &= ~PF_WQ_WORKER;
+               return 0;
+       }
+
        /* rescuers should never participate in concurrency management */
        WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING));
        schedule();
@@ -3218,7 +3255,7 @@ static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr,
                return -ENOMEM;
 
        if (sscanf(buf, "%d", &attrs->nice) == 1 &&
-           attrs->nice >= -20 && attrs->nice <= 19)
+           attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE)
                ret = apply_workqueue_attrs(wq, attrs);
        else
                ret = -EINVAL;
@@ -4086,7 +4123,8 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
        if (!pwq) {
                pr_warning("workqueue: allocation failed while updating NUMA affinity of \"%s\"\n",
                           wq->name);
-               goto out_unlock;
+               mutex_lock(&wq->mutex);
+               goto use_dfl_pwq;
        }
 
        /*