aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2011-01-21 13:38:57 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-21 13:38:57 -0800
commit5bf7a6503ff416214b9a53569677dbf07657e6fd (patch)
tree0dc8e8dbc30a23d466a327bef05e78c571f2b8a3
parent0f5c2ac58f22fd41deaeeb45ee752d4ae55f0d01 (diff)
parent42c025f3de9042d9c9abd9a6f6205d1a0f4bcadf (diff)
downloadlinux-linaro-5bf7a6503ff416214b9a53569677dbf07657e6fd.tar.gz
Merge branch 'fixes-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
* 'fixes-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: note the nested NOT_RUNNING test in worker_clr_flags() isn't a noop workqueue: relax lockdep annotation on flush_work()
-rw-r--r--include/linux/lockdep.h3
-rw-r--r--kernel/workqueue.c20
2 files changed, 20 insertions, 3 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index f638fd78d10..4aef1dda640 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -514,12 +514,15 @@ static inline void print_irqtrace_events(struct task_struct *curr)
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# ifdef CONFIG_PROVE_LOCKING
# define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 2, NULL, _THIS_IP_)
+# define lock_map_acquire_read(l) lock_acquire(l, 0, 0, 2, 2, NULL, _THIS_IP_)
# else
# define lock_map_acquire(l) lock_acquire(l, 0, 0, 0, 1, NULL, _THIS_IP_)
+# define lock_map_acquire_read(l) lock_acquire(l, 0, 0, 2, 1, NULL, _THIS_IP_)
# endif
# define lock_map_release(l) lock_release(l, 1, _THIS_IP_)
#else
# define lock_map_acquire(l) do { } while (0)
+# define lock_map_acquire_read(l) do { } while (0)
# define lock_map_release(l) do { } while (0)
#endif
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 8ee6ec82f88..11869faa681 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -768,7 +768,11 @@ 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 +1844,7 @@ __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);
@@ -2384,8 +2388,18 @@ 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);