1 files changed, 41 insertions, 16 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 8ee6ec82f88..ee6578b578a 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -79,7 +79,9 @@ enum {
         MAX_IDLE_WORKERS_RATIO  = 4,            /* 1/4 of busy can be idle */
         IDLE_WORKER_TIMEOUT     = 300 * HZ,     /* keep idle ones for 5 mins */
 
-        MAYDAY_INITIAL_TIMEOUT  = HZ / 100,     /* call for help after 10ms */
+        MAYDAY_INITIAL_TIMEOUT  = HZ / 100 >= 2 ? HZ / 100 : 2,
+                                                /* call for help after 10ms
+                                                   (min two ticks) */
         MAYDAY_INTERVAL         = HZ / 10,      /* and then every 100ms */
         CREATE_COOLDOWN         = HZ,           /* time to breath after fail */
         TRUSTEE_COOLDOWN        = HZ / 10,      /* for trustee draining */
@@ -768,7 +770,11 @@ static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
 
         worker->flags &= ~flags;
 
-        /* if transitioning out of NOT_RUNNING, increment nr_running */
+        /*
+         * If transitioning out of NOT_RUNNING, increment nr_running.  Note
+         * that the nested NOT_RUNNING is not a noop.  NOT_RUNNING is mask
+         * of multiple flags, not a single flag.
+         */
         if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING))
                 if (!(worker->flags & WORKER_NOT_RUNNING))
                         atomic_inc(get_gcwq_nr_running(gcwq->cpu));
@@ -1840,7 +1846,7 @@ __acquires(&gcwq->lock)
         spin_unlock_irq(&gcwq->lock);
 
         work_clear_pending(work);
-        lock_map_acquire(&cwq->wq->lockdep_map);
+        lock_map_acquire_read(&cwq->wq->lockdep_map);
         lock_map_acquire(&lockdep_map);
         trace_workqueue_execute_start(work);
         f(work);
@@ -2043,6 +2049,15 @@ repeat:
                                 move_linked_works(work, scheduled, &n);
 
                 process_scheduled_works(rescuer);
+
+                /*
+                 * Leave this gcwq.  If keep_working() is %true, notify a
+                 * regular worker; otherwise, we end up with 0 concurrency
+                 * and stalling the execution.
+                 */
+                if (keep_working(gcwq))
+                        wake_up_worker(gcwq);
+
                 spin_unlock_irq(&gcwq->lock);
         }
 
@@ -2384,8 +2399,18 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
         insert_wq_barrier(cwq, barr, work, worker);
         spin_unlock_irq(&gcwq->lock);
 
-        lock_map_acquire(&cwq->wq->lockdep_map);
+        /*
+         * If @max_active is 1 or rescuer is in use, flushing another work
+         * item on the same workqueue may lead to deadlock.  Make sure the
+         * flusher is not running on the same workqueue by verifying write
+         * access.
+         */
+        if (cwq->wq->saved_max_active == 1 || cwq->wq->flags & WQ_RESCUER)
+                lock_map_acquire(&cwq->wq->lockdep_map);
+        else
+                lock_map_acquire_read(&cwq->wq->lockdep_map);
         lock_map_release(&cwq->wq->lockdep_map);
+
         return true;
 already_gone:
         spin_unlock_irq(&gcwq->lock);
@@ -2942,7 +2967,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *name,
          */
         spin_lock(&workqueue_lock);
 
-        if (workqueue_freezing && wq->flags & WQ_FREEZEABLE)
+        if (workqueue_freezing && wq->flags & WQ_FREEZABLE)
                 for_each_cwq_cpu(cpu, wq)
                         get_cwq(cpu, wq)->max_active = 0;
 
@@ -3054,7 +3079,7 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
 
                 spin_lock_irq(&gcwq->lock);
 
-                if (!(wq->flags & WQ_FREEZEABLE) ||
+                if (!(wq->flags & WQ_FREEZABLE) ||
                     !(gcwq->flags & GCWQ_FREEZING))
                         get_cwq(gcwq->cpu, wq)->max_active = max_active;
 
@@ -3304,7 +3329,7 @@ static int __cpuinit trustee_thread(void *__gcwq)
          * want to get it over with ASAP - spam rescuers, wake up as
          * many idlers as necessary and create new ones till the
          * worklist is empty.  Note that if the gcwq is frozen, there
-         * may be frozen works in freezeable cwqs.  Don't declare
+         * may be frozen works in freezable cwqs.  Don't declare
          * completion while frozen.
          */
         while (gcwq->nr_workers != gcwq->nr_idle ||
@@ -3562,9 +3587,9 @@ EXPORT_SYMBOL_GPL(work_on_cpu);
 /**
  * freeze_workqueues_begin - begin freezing workqueues
  *
- * Start freezing workqueues.  After this function returns, all
- * freezeable workqueues will queue new works to their frozen_works
- * list instead of gcwq->worklist.
+ * Start freezing workqueues.  After this function returns, all freezable
+ * workqueues will queue new works to their frozen_works list instead of
+ * gcwq->worklist.
  *
  * CONTEXT:
  * Grabs and releases workqueue_lock and gcwq->lock's.
@@ -3590,7 +3615,7 @@ void freeze_workqueues_begin(void)
                 list_for_each_entry(wq, &workqueues, list) {
                         struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
 
-                        if (cwq && wq->flags & WQ_FREEZEABLE)
+                        if (cwq && wq->flags & WQ_FREEZABLE)
                                 cwq->max_active = 0;
                 }
 
@@ -3601,7 +3626,7 @@ void freeze_workqueues_begin(void)
 }
 
 /**
- * freeze_workqueues_busy - are freezeable workqueues still busy?
+ * freeze_workqueues_busy - are freezable workqueues still busy?
  *
  * Check whether freezing is complete.  This function must be called
  * between freeze_workqueues_begin() and thaw_workqueues().
@@ -3610,8 +3635,8 @@ void freeze_workqueues_begin(void)
  * Grabs and releases workqueue_lock.
  *
  * RETURNS:
- * %true if some freezeable workqueues are still busy.  %false if
- * freezing is complete.
+ * %true if some freezable workqueues are still busy.  %false if freezing
+ * is complete.
  */
 bool freeze_workqueues_busy(void)
 {
@@ -3631,7 +3656,7 @@ bool freeze_workqueues_busy(void)
                 list_for_each_entry(wq, &workqueues, list) {
                         struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
 
-                        if (!cwq || !(wq->flags & WQ_FREEZEABLE))
+                        if (!cwq || !(wq->flags & WQ_FREEZABLE))
                                 continue;
 
                         BUG_ON(cwq->nr_active < 0);
@@ -3676,7 +3701,7 @@ void thaw_workqueues(void)
                 list_for_each_entry(wq, &workqueues, list) {
                         struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
 
-                        if (!cwq || !(wq->flags & WQ_FREEZEABLE))
+                        if (!cwq || !(wq->flags & WQ_FREEZABLE))
                                 continue;
 
                         /* restore max_active and repopulate worklist */