Merge branch 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

Pull workqueue changes from Tejun Heo:
 "This is workqueue updates for v3.7-rc1.  A lot of activities this
  round including considerable API and behavior cleanups.

   * delayed_work combines a timer and a work item.  The handling of the
     timer part has always been a bit clunky leading to confusing
     cancelation API with weird corner-case behaviors.  delayed_work is
     updated to use new IRQ safe timer and cancelation now works as
     expected.

   * Another deficiency of delayed_work was lack of the counterpart of
     mod_timer() which led to cancel+queue combinations or open-coded
     timer+work usages.  mod_delayed_work[_on]() are added.

     These two delayed_work changes make delayed_work provide interface
     and behave like timer which is executed with process context.

   * A work item could be executed concurrently on multiple CPUs, which
     is rather unintuitive and made flush_work() behavior confusing and
     half-broken under certain circumstances.  This problem doesn't
     exist for non-reentrant workqueues.  While non-reentrancy check
     isn't free, the overhead is incurred only when a work item bounces
     across different CPUs and even in simulated pathological scenario
     the overhead isn't too high.

     All workqueues are made non-reentrant.  This removes the
     distinction between flush_[delayed_]work() and
     flush_[delayed_]_work_sync().  The former is now as strong as the
     latter and the specified work item is guaranteed to have finished
     execution of any previous queueing on return.

   * In addition to the various bug fixes, Lai redid and simplified CPU
     hotplug handling significantly.

   * Joonsoo introduced system_highpri_wq and used it during CPU
     hotplug.

  There are two merge commits - one to pull in IRQ safe timer from
  tip/timers/core and the other to pull in CPU hotplug fixes from
  wq/for-3.6-fixes as Lai's hotplug restructuring depended on them."

Fixed a number of trivial conflicts, but the more interesting conflicts
were silent ones where the deprecated interfaces had been used by new
code in the merge window, and thus didn't cause any real data conflicts.

Tejun pointed out a few of them, I fixed a couple more.

* 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (46 commits)
  workqueue: remove spurious WARN_ON_ONCE(in_irq()) from try_to_grab_pending()
  workqueue: use cwq_set_max_active() helper for workqueue_set_max_active()
  workqueue: introduce cwq_set_max_active() helper for thaw_workqueues()
  workqueue: remove @delayed from cwq_dec_nr_in_flight()
  workqueue: fix possible stall on try_to_grab_pending() of a delayed work item
  workqueue: use hotcpu_notifier() for workqueue_cpu_down_callback()
  workqueue: use __cpuinit instead of __devinit for cpu callbacks
  workqueue: rename manager_mutex to assoc_mutex
  workqueue: WORKER_REBIND is no longer necessary for idle rebinding
  workqueue: WORKER_REBIND is no longer necessary for busy rebinding
  workqueue: reimplement idle worker rebinding
  workqueue: deprecate __cancel_delayed_work()
  workqueue: reimplement cancel_delayed_work() using try_to_grab_pending()
  workqueue: use mod_delayed_work() instead of __cancel + queue
  workqueue: use irqsafe timer for delayed_work
  workqueue: clean up delayed_work initializers and add missing one
  workqueue: make deferrable delayed_work initializer names consistent
  workqueue: cosmetic whitespace updates for macro definitions
  workqueue: deprecate system_nrt[_freezable]_wq
  workqueue: deprecate flush[_delayed]_work_sync()
  ...

1 files changed, 122 insertions, 98 deletions

diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index af155450cab..2b58905d350 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -16,6 +16,7 @@ struct workqueue_struct;
 
 struct work_struct;
 typedef void (*work_func_t)(struct work_struct *work);
+void delayed_work_timer_fn(unsigned long __data);
 
 /*
  * The first word is the work queue pointer and the flags rolled into
@@ -67,9 +68,18 @@ enum {
 	WORK_STRUCT_FLAG_BITS	= WORK_STRUCT_COLOR_SHIFT +
 				  WORK_STRUCT_COLOR_BITS,
 
+	/* data contains off-queue information when !WORK_STRUCT_CWQ */
+	WORK_OFFQ_FLAG_BASE	= WORK_STRUCT_FLAG_BITS,
+
+	WORK_OFFQ_CANCELING	= (1 << WORK_OFFQ_FLAG_BASE),
+
+	WORK_OFFQ_FLAG_BITS	= 1,
+	WORK_OFFQ_CPU_SHIFT	= WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
+
+	/* convenience constants */
 	WORK_STRUCT_FLAG_MASK	= (1UL << WORK_STRUCT_FLAG_BITS) - 1,
 	WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
-	WORK_STRUCT_NO_CPU	= WORK_CPU_NONE << WORK_STRUCT_FLAG_BITS,
+	WORK_STRUCT_NO_CPU	= (unsigned long)WORK_CPU_NONE << WORK_OFFQ_CPU_SHIFT,
 
 	/* bit mask for work_busy() return values */
 	WORK_BUSY_PENDING	= 1 << 0,
@@ -92,6 +102,7 @@ struct work_struct {
 struct delayed_work {
 	struct work_struct work;
 	struct timer_list timer;
+	int cpu;
 };
 
 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
@@ -115,41 +126,38 @@ struct execute_work {
 #define __WORK_INIT_LOCKDEP_MAP(n, k)
 #endif
 
-#define __WORK_INITIALIZER(n, f) {				\
-	.data = WORK_DATA_STATIC_INIT(),			\
-	.entry	= { &(n).entry, &(n).entry },			\
-	.func = (f),						\
-	__WORK_INIT_LOCKDEP_MAP(#n, &(n))			\
+#define __WORK_INITIALIZER(n, f) {					\
+	.data = WORK_DATA_STATIC_INIT(),				\
+	.entry	= { &(n).entry, &(n).entry },				\
+	.func = (f),							\
+	__WORK_INIT_LOCKDEP_MAP(#n, &(n))				\
 	}
 
-#define __DELAYED_WORK_INITIALIZER(n, f) {			\
-	.work = __WORK_INITIALIZER((n).work, (f)),		\
-	.timer = TIMER_INITIALIZER(NULL, 0, 0),			\
+#define __DELAYED_WORK_INITIALIZER(n, f, tflags) {			\
+	.work = __WORK_INITIALIZER((n).work, (f)),			\
+	.timer = __TIMER_INITIALIZER(delayed_work_timer_fn,		\
+				     0, (unsigned long)&(n),		\
+				     (tflags) | TIMER_IRQSAFE),		\
 	}
 
-#define __DEFERRED_WORK_INITIALIZER(n, f) {			\
-	.work = __WORK_INITIALIZER((n).work, (f)),		\
-	.timer = TIMER_DEFERRED_INITIALIZER(NULL, 0, 0),	\
-	}
-
-#define DECLARE_WORK(n, f)					\
+#define DECLARE_WORK(n, f)						\
 	struct work_struct n = __WORK_INITIALIZER(n, f)
 
-#define DECLARE_DELAYED_WORK(n, f)				\
-	struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f)
+#define DECLARE_DELAYED_WORK(n, f)					\
+	struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
 
-#define DECLARE_DEFERRED_WORK(n, f)				\
-	struct delayed_work n = __DEFERRED_WORK_INITIALIZER(n, f)
+#define DECLARE_DEFERRABLE_WORK(n, f)					\
+	struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
 
 /*
  * initialize a work item's function pointer
  */
-#define PREPARE_WORK(_work, _func)				\
-	do {							\
-		(_work)->func = (_func);			\
+#define PREPARE_WORK(_work, _func)					\
+	do {								\
+		(_work)->func = (_func);				\
 	} while (0)
 
-#define PREPARE_DELAYED_WORK(_work, _func)			\
+#define PREPARE_DELAYED_WORK(_work, _func)				\
 	PREPARE_WORK(&(_work)->work, (_func))
 
 #ifdef CONFIG_DEBUG_OBJECTS_WORK
@@ -179,7 +187,7 @@ static inline unsigned int work_static(struct work_struct *work) { return 0; }
 									\
 		__init_work((_work), _onstack);				\
 		(_work)->data = (atomic_long_t) WORK_DATA_INIT();	\
-		lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0);\
+		lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0); \
 		INIT_LIST_HEAD(&(_work)->entry);			\
 		PREPARE_WORK((_work), (_func));				\
 	} while (0)
@@ -193,33 +201,44 @@ static inline unsigned int work_static(struct work_struct *work) { return 0; }
 	} while (0)
 #endif
 
-#define INIT_WORK(_work, _func)					\
-	do {							\
-		__INIT_WORK((_work), (_func), 0);		\
+#define INIT_WORK(_work, _func)						\
+	do {								\
+		__INIT_WORK((_work), (_func), 0);			\
 	} while (0)
 
-#define INIT_WORK_ONSTACK(_work, _func)				\
-	do {							\
-		__INIT_WORK((_work), (_func), 1);		\
+#define INIT_WORK_ONSTACK(_work, _func)					\
+	do {								\
+		__INIT_WORK((_work), (_func), 1);			\
 	} while (0)
 
-#define INIT_DELAYED_WORK(_work, _func)				\
-	do {							\
-		INIT_WORK(&(_work)->work, (_func));		\
-		init_timer(&(_work)->timer);			\
+#define __INIT_DELAYED_WORK(_work, _func, _tflags)			\
+	do {								\
+		INIT_WORK(&(_work)->work, (_func));			\
+		__setup_timer(&(_work)->timer, delayed_work_timer_fn,	\
+			      (unsigned long)(_work),			\
+			      (_tflags) | TIMER_IRQSAFE);		\
 	} while (0)
 
-#define INIT_DELAYED_WORK_ONSTACK(_work, _func)			\
-	do {							\
-		INIT_WORK_ONSTACK(&(_work)->work, (_func));	\
-		init_timer_on_stack(&(_work)->timer);		\
+#define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags)		\
+	do {								\
+		INIT_WORK_ONSTACK(&(_work)->work, (_func));		\
+		__setup_timer_on_stack(&(_work)->timer,			\
+				       delayed_work_timer_fn,		\
+				       (unsigned long)(_work),		\
+				       (_tflags) | TIMER_IRQSAFE);	\
 	} while (0)
 
-#define INIT_DELAYED_WORK_DEFERRABLE(_work, _func)		\
-	do {							\
-		INIT_WORK(&(_work)->work, (_func));		\
-		init_timer_deferrable(&(_work)->timer);		\
-	} while (0)
+#define INIT_DELAYED_WORK(_work, _func)					\
+	__INIT_DELAYED_WORK(_work, _func, 0)
+
+#define INIT_DELAYED_WORK_ONSTACK(_work, _func)				\
+	__INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
+
+#define INIT_DEFERRABLE_WORK(_work, _func)				\
+	__INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
+
+#define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func)			\
+	__INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
 
 /**
  * work_pending - Find out whether a work item is currently pending
@@ -278,10 +297,6 @@ enum {
  * system_long_wq is similar to system_wq but may host long running
  * works.  Queue flushing might take relatively long.
  *
- * system_nrt_wq is non-reentrant and guarantees that any given work
- * item is never executed in parallel by multiple CPUs.  Queue
- * flushing might take relatively long.
- *
  * system_unbound_wq is unbound workqueue.  Workers are not bound to
  * any specific CPU, not concurrency managed, and all queued works are
  * executed immediately as long as max_active limit is not reached and
@@ -289,16 +304,25 @@ enum {
  *
  * system_freezable_wq is equivalent to system_wq except that it's
  * freezable.
- *
- * system_nrt_freezable_wq is equivalent to system_nrt_wq except that
- * it's freezable.
  */
 extern struct workqueue_struct *system_wq;
 extern struct workqueue_struct *system_long_wq;
-extern struct workqueue_struct *system_nrt_wq;
 extern struct workqueue_struct *system_unbound_wq;
 extern struct workqueue_struct *system_freezable_wq;
-extern struct workqueue_struct *system_nrt_freezable_wq;
+
+static inline struct workqueue_struct * __deprecated __system_nrt_wq(void)
+{
+	return system_wq;
+}
+
+static inline struct workqueue_struct * __deprecated __system_nrt_freezable_wq(void)
+{
+	return system_freezable_wq;
+}
+
+/* equivlalent to system_wq and system_freezable_wq, deprecated */
+#define system_nrt_wq			__system_nrt_wq()
+#define system_nrt_freezable_wq		__system_nrt_freezable_wq()
 
 extern struct workqueue_struct *
 __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
@@ -321,22 +345,22 @@ __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
  * Pointer to the allocated workqueue on success, %NULL on failure.
  */
 #ifdef CONFIG_LOCKDEP
-#define alloc_workqueue(fmt, flags, max_active, args...)	\
-({								\
-	static struct lock_class_key __key;			\
-	const char *__lock_name;				\
-								\
-	if (__builtin_constant_p(fmt))				\
-		__lock_name = (fmt);				\
-	else							\
-		__lock_name = #fmt;				\
-								\
-	__alloc_workqueue_key((fmt), (flags), (max_active),	\
-			      &__key, __lock_name, ##args);	\
+#define alloc_workqueue(fmt, flags, max_active, args...)		\
+({									\
+	static struct lock_class_key __key;				\
+	const char *__lock_name;					\
+									\
+	if (__builtin_constant_p(fmt))					\
+		__lock_name = (fmt);					\
+	else								\
+		__lock_name = #fmt;					\
+									\
+	__alloc_workqueue_key((fmt), (flags), (max_active),		\
+			      &__key, __lock_name, ##args);		\
 })
 #else
-#define alloc_workqueue(fmt, flags, max_active, args...)	\
-	__alloc_workqueue_key((fmt), (flags), (max_active),	\
+#define alloc_workqueue(fmt, flags, max_active, args...)		\
+	__alloc_workqueue_key((fmt), (flags), (max_active),		\
 			      NULL, NULL, ##args)
 #endif
 
@@ -353,46 +377,50 @@ __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
  * RETURNS:
  * Pointer to the allocated workqueue on success, %NULL on failure.
  */
-#define alloc_ordered_workqueue(fmt, flags, args...)		\
+#define alloc_ordered_workqueue(fmt, flags, args...)			\
 	alloc_workqueue(fmt, WQ_UNBOUND | (flags), 1, ##args)
 
-#define create_workqueue(name)					\
+#define create_workqueue(name)						\
 	alloc_workqueue((name), WQ_MEM_RECLAIM, 1)
-#define create_freezable_workqueue(name)			\
+#define create_freezable_workqueue(name)				\
 	alloc_workqueue((name), WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, 1)
-#define create_singlethread_workqueue(name)			\
+#define create_singlethread_workqueue(name)				\
 	alloc_workqueue((name), WQ_UNBOUND | WQ_MEM_RECLAIM, 1)
 
 extern void destroy_workqueue(struct workqueue_struct *wq);
 
-extern int queue_work(struct workqueue_struct *wq, struct work_struct *work);
-extern int queue_work_on(int cpu, struct workqueue_struct *wq,
+extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
 			struct work_struct *work);
-extern int queue_delayed_work(struct workqueue_struct *wq,
+extern bool queue_work(struct workqueue_struct *wq, struct work_struct *work);
+extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 			struct delayed_work *work, unsigned long delay);
-extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
+extern bool queue_delayed_work(struct workqueue_struct *wq,
 			struct delayed_work *work, unsigned long delay);
+extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
+			struct delayed_work *dwork, unsigned long delay);
+extern bool mod_delayed_work(struct workqueue_struct *wq,
+			struct delayed_work *dwork, unsigned long delay);
 
 extern void flush_workqueue(struct workqueue_struct *wq);
 extern void drain_workqueue(struct workqueue_struct *wq);
 extern void flush_scheduled_work(void);
 
-extern int schedule_work(struct work_struct *work);
-extern int schedule_work_on(int cpu, struct work_struct *work);
-extern int schedule_delayed_work(struct delayed_work *work, unsigned long delay);
-extern int schedule_delayed_work_on(int cpu, struct delayed_work *work,
-					unsigned long delay);
+extern bool schedule_work_on(int cpu, struct work_struct *work);
+extern bool schedule_work(struct work_struct *work);
+extern bool schedule_delayed_work_on(int cpu, struct delayed_work *work,
+				     unsigned long delay);
+extern bool schedule_delayed_work(struct delayed_work *work,
+				  unsigned long delay);
 extern int schedule_on_each_cpu(work_func_t func);
 extern int keventd_up(void);
 
 int execute_in_process_context(work_func_t fn, struct execute_work *);
 
 extern bool flush_work(struct work_struct *work);
-extern bool flush_work_sync(struct work_struct *work);
 extern bool cancel_work_sync(struct work_struct *work);
 
 extern bool flush_delayed_work(struct delayed_work *dwork);
-extern bool flush_delayed_work_sync(struct delayed_work *work);
+extern bool cancel_delayed_work(struct delayed_work *dwork);
 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
 
 extern void workqueue_set_max_active(struct workqueue_struct *wq,
@@ -402,27 +430,11 @@ extern unsigned int work_cpu(struct work_struct *work);
 extern unsigned int work_busy(struct work_struct *work);
 
 /*
- * Kill off a pending schedule_delayed_work().  Note that the work callback
- * function may still be running on return from cancel_delayed_work(), unless
- * it returns 1 and the work doesn't re-arm itself. Run flush_workqueue() or
- * cancel_work_sync() to wait on it.
- */
-static inline bool cancel_delayed_work(struct delayed_work *work)
-{
-	bool ret;
-
-	ret = del_timer_sync(&work->timer);
-	if (ret)
-		work_clear_pending(&work->work);
-	return ret;
-}
-
-/*
  * Like above, but uses del_timer() instead of del_timer_sync(). This means,
  * if it returns 0 the timer function may be running and the queueing is in
  * progress.
  */
-static inline bool __cancel_delayed_work(struct delayed_work *work)
+static inline bool __deprecated __cancel_delayed_work(struct delayed_work *work)
 {
 	bool ret;
 
@@ -432,6 +444,18 @@ static inline bool __cancel_delayed_work(struct delayed_work *work)
 	return ret;
 }
 
+/* used to be different but now identical to flush_work(), deprecated */
+static inline bool __deprecated flush_work_sync(struct work_struct *work)
+{
+	return flush_work(work);
+}
+
+/* used to be different but now identical to flush_delayed_work(), deprecated */
+static inline bool __deprecated flush_delayed_work_sync(struct delayed_work *dwork)
+{
+	return flush_delayed_work(dwork);
+}
+
 #ifndef CONFIG_SMP
 static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
 {