Merge branch 'sched-hrtimers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Thomas Gleixner:
 "This series of scheduler updates depends on sched/core and timers/core
  branches, which are already in your tree:

   - Scheduler balancing overhaul to plug a hard to trigger race which
     causes an oops in the balancer (Peter Zijlstra)

   - Lockdep updates which are related to the balancing updates (Peter
     Zijlstra)"

* 'sched-hrtimers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched,lockdep: Employ lock pinning
  lockdep: Implement lock pinning
  lockdep: Simplify lock_release()
  sched: Streamline the task migration locking a little
  sched: Move code around
  sched,dl: Fix sched class hopping CBS hole
  sched, dl: Convert switched_{from, to}_dl() / prio_changed_dl() to balance callbacks
  sched,dl: Remove return value from pull_dl_task()
  sched, rt: Convert switched_{from, to}_rt() / prio_changed_rt() to balance callbacks
  sched,rt: Remove return value from pull_rt_task()
  sched: Allow balance callbacks for check_class_changed()
  sched: Use replace normalize_task() with __sched_setscheduler()
  sched: Replace post_schedule with a balance callback list

1 files changed, 87 insertions, 90 deletions

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 456614136f1a..8acfbf773e06 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3157,6 +3157,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
         hlock->waittime_stamp = 0;
         hlock->holdtime_stamp = lockstat_clock();
 #endif
+        hlock->pin_count = 0;
 
         if (check && !mark_irqflags(curr, hlock))
                 return 0;
@@ -3260,26 +3261,6 @@ print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
         return 0;
 }
 
-/*
- * Common debugging checks for both nested and non-nested unlock:
- */
-static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
-                        unsigned long ip)
-{
-        if (unlikely(!debug_locks))
-                return 0;
-        /*
-         * Lockdep should run with IRQs disabled, recursion, head-ache, etc..
-         */
-        if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
-                return 0;
-
-        if (curr->lockdep_depth <= 0)
-                return print_unlock_imbalance_bug(curr, lock, ip);
-
-        return 1;
-}
-
 static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
 {
         if (hlock->instance == lock)
@@ -3376,31 +3357,35 @@ found_it:
 }
 
 /*
- * Remove the lock to the list of currently held locks in a
- * potentially non-nested (out of order) manner. This is a
- * relatively rare operation, as all the unlock APIs default
- * to nested mode (which uses lock_release()):
+ * Remove the lock to the list of currently held locks - this gets
+ * called on mutex_unlock()/spin_unlock*() (or on a failed
+ * mutex_lock_interruptible()).
+ *
+ * @nested is an hysterical artifact, needs a tree wide cleanup.
  */
 static int
-lock_release_non_nested(struct task_struct *curr,
-                        struct lockdep_map *lock, unsigned long ip)
+__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
 {
+        struct task_struct *curr = current;
         struct held_lock *hlock, *prev_hlock;
         unsigned int depth;
         int i;
 
-        /*
-         * Check whether the lock exists in the current stack
-         * of held locks:
-         */
+        if (unlikely(!debug_locks))
+                return 0;
+
         depth = curr->lockdep_depth;
         /*
          * So we're all set to release this lock.. wait what lock? We don't
          * own any locks, you've been drinking again?
          */
-        if (DEBUG_LOCKS_WARN_ON(!depth))
-                return 0;
+        if (DEBUG_LOCKS_WARN_ON(depth <= 0))
+                 return print_unlock_imbalance_bug(curr, lock, ip);
 
+        /*
+         * Check whether the lock exists in the current stack
+         * of held locks:
+         */
         prev_hlock = NULL;
         for (i = depth-1; i >= 0; i--) {
                 hlock = curr->held_locks + i;
@@ -3419,6 +3404,8 @@ found_it:
         if (hlock->instance == lock)
                 lock_release_holdtime(hlock);
 
+        WARN(hlock->pin_count, "releasing a pinned lock\n");
+
         if (hlock->references) {
                 hlock->references--;
                 if (hlock->references) {
@@ -3456,91 +3443,66 @@ found_it:
          */
         if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
                 return 0;
+
         return 1;
 }
 
-/*
- * Remove the lock to the list of currently held locks - this gets
- * called on mutex_unlock()/spin_unlock*() (or on a failed
- * mutex_lock_interruptible()). This is done for unlocks that nest
- * perfectly. (i.e. the current top of the lock-stack is unlocked)
- */
-static int lock_release_nested(struct task_struct *curr,
-                               struct lockdep_map *lock, unsigned long ip)
+static int __lock_is_held(struct lockdep_map *lock)
 {
-        struct held_lock *hlock;
-        unsigned int depth;
-
-        /*
-         * Pop off the top of the lock stack:
-         */
-        depth = curr->lockdep_depth - 1;
-        hlock = curr->held_locks + depth;
-
-        /*
-         * Is the unlock non-nested:
-         */
-        if (hlock->instance != lock || hlock->references)
-                return lock_release_non_nested(curr, lock, ip);
-        curr->lockdep_depth--;
-
-        /*
-         * No more locks, but somehow we've got hash left over, who left it?
-         */
-        if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0)))
-                return 0;
+        struct task_struct *curr = current;
+        int i;
 
-        curr->curr_chain_key = hlock->prev_chain_key;
+        for (i = 0; i < curr->lockdep_depth; i++) {
+                struct held_lock *hlock = curr->held_locks + i;
 
-        lock_release_holdtime(hlock);
+                if (match_held_lock(hlock, lock))
+                        return 1;
+        }
 
-#ifdef CONFIG_DEBUG_LOCKDEP
-        hlock->prev_chain_key = 0;
-        hlock->class_idx = 0;
-        hlock->acquire_ip = 0;
-        hlock->irq_context = 0;
-#endif
-        return 1;
+        return 0;
 }
 
-/*
- * Remove the lock to the list of currently held locks - this gets
- * called on mutex_unlock()/spin_unlock*() (or on a failed
- * mutex_lock_interruptible()). This is done for unlocks that nest
- * perfectly. (i.e. the current top of the lock-stack is unlocked)
- */
-static void
-__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
+static void __lock_pin_lock(struct lockdep_map *lock)
 {
         struct task_struct *curr = current;
+        int i;
 
-        if (!check_unlock(curr, lock, ip))
+        if (unlikely(!debug_locks))
                 return;
 
-        if (nested) {
-                if (!lock_release_nested(curr, lock, ip))
-                        return;
-        } else {
-                if (!lock_release_non_nested(curr, lock, ip))
+        for (i = 0; i < curr->lockdep_depth; i++) {
+                struct held_lock *hlock = curr->held_locks + i;
+
+                if (match_held_lock(hlock, lock)) {
+                        hlock->pin_count++;
                         return;
+                }
         }
 
-        check_chain_key(curr);
+        WARN(1, "pinning an unheld lock\n");
 }
 
-static int __lock_is_held(struct lockdep_map *lock)
+static void __lock_unpin_lock(struct lockdep_map *lock)
 {
         struct task_struct *curr = current;
         int i;
 
+        if (unlikely(!debug_locks))
+                return;
+
         for (i = 0; i < curr->lockdep_depth; i++) {
                 struct held_lock *hlock = curr->held_locks + i;
 
-                if (match_held_lock(hlock, lock))
-                        return 1;
+                if (match_held_lock(hlock, lock)) {
+                        if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n"))
+                                return;
+
+                        hlock->pin_count--;
+                        return;
+                }
         }
 
-        return 0;
+        WARN(1, "unpinning an unheld lock\n");
 }
 
 /*
@@ -3639,7 +3601,8 @@ void lock_release(struct lockdep_map *lock, int nested,
         check_flags(flags);
         current->lockdep_recursion = 1;
         trace_lock_release(lock, ip);
-        __lock_release(lock, nested, ip);
+        if (__lock_release(lock, nested, ip))
+                check_chain_key(current);
         current->lockdep_recursion = 0;
         raw_local_irq_restore(flags);
 }
@@ -3665,6 +3628,40 @@ int lock_is_held(struct lockdep_map *lock)
 }
 EXPORT_SYMBOL_GPL(lock_is_held);
 
+void lock_pin_lock(struct lockdep_map *lock)
+{
+        unsigned long flags;
+
+        if (unlikely(current->lockdep_recursion))
+                return;
+
+        raw_local_irq_save(flags);
+        check_flags(flags);
+
+        current->lockdep_recursion = 1;
+        __lock_pin_lock(lock);
+        current->lockdep_recursion = 0;
+        raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_pin_lock);
+
+void lock_unpin_lock(struct lockdep_map *lock)
+{
+        unsigned long flags;
+
+        if (unlikely(current->lockdep_recursion))
+                return;
+
+        raw_local_irq_save(flags);
+        check_flags(flags);
+
+        current->lockdep_recursion = 1;
+        __lock_unpin_lock(lock);
+        current->lockdep_recursion = 0;
+        raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_unpin_lock);
+
 void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
 {
         current->lockdep_reclaim_gfp = gfp_mask;