1 files changed, 80 insertions, 0 deletions

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index a266d5165b63..18f9f434d17e 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;
@@ -3403,6 +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) {
@@ -3459,6 +3462,49 @@ static int __lock_is_held(struct lockdep_map *lock)
         return 0;
 }
 
+static void __lock_pin_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)) {
+                        hlock->pin_count++;
+                        return;
+                }
+        }
+
+        WARN(1, "pinning an unheld lock\n");
+}
+
+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)) {
+                        if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n"))
+                                return;
+
+                        hlock->pin_count--;
+                        return;
+                }
+        }
+
+        WARN(1, "unpinning an unheld lock\n");
+}
+
 /*
  * Check whether we follow the irq-flags state precisely:
  */
@@ -3582,6 +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;