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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2008-08-11 03:30:21 -0400
committerIngo Molnar <mingo@elte.hu>2008-08-11 03:30:21 -0400
commit64aa348edc617dea17bbd01ddee4e47886d5ec8c (patch)
tree002b5fa796aff225d0cb9d0c32bb3ba96da6eaaf /kernel/lockdep.c
parent5e710e37bde120bb069f691bee68e69ef4393173 (diff)
lockdep: lock_set_subclass - reset a held lock's subclass
this can be used to reset a held lock's subclass, for arbitrary-depth iterated data structures such as trees or lists which have per-node locks. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/lockdep.c')
-rw-r--r--kernel/lockdep.c69
1 files changed, 69 insertions, 0 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 6999e64fc248..e14d383dcb0b 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2660,6 +2660,55 @@ static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
2660 return 1; 2660 return 1;
2661} 2661}
2662 2662
2663static int
2664__lock_set_subclass(struct lockdep_map *lock,
2665 unsigned int subclass, unsigned long ip)
2666{
2667 struct task_struct *curr = current;
2668 struct held_lock *hlock, *prev_hlock;
2669 struct lock_class *class;
2670 unsigned int depth;
2671 int i;
2672
2673 depth = curr->lockdep_depth;
2674 if (DEBUG_LOCKS_WARN_ON(!depth))
2675 return 0;
2676
2677 prev_hlock = NULL;
2678 for (i = depth-1; i >= 0; i--) {
2679 hlock = curr->held_locks + i;
2680 /*
2681 * We must not cross into another context:
2682 */
2683 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
2684 break;
2685 if (hlock->instance == lock)
2686 goto found_it;
2687 prev_hlock = hlock;
2688 }
2689 return print_unlock_inbalance_bug(curr, lock, ip);
2690
2691found_it:
2692 class = register_lock_class(lock, subclass, 0);
2693 hlock->class = class;
2694
2695 curr->lockdep_depth = i;
2696 curr->curr_chain_key = hlock->prev_chain_key;
2697
2698 for (; i < depth; i++) {
2699 hlock = curr->held_locks + i;
2700 if (!__lock_acquire(hlock->instance,
2701 hlock->class->subclass, hlock->trylock,
2702 hlock->read, hlock->check, hlock->hardirqs_off,
2703 hlock->acquire_ip))
2704 return 0;
2705 }
2706
2707 if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
2708 return 0;
2709 return 1;
2710}
2711
2663/* 2712/*
2664 * Remove the lock to the list of currently held locks in a 2713 * Remove the lock to the list of currently held locks in a
2665 * potentially non-nested (out of order) manner. This is a 2714 * potentially non-nested (out of order) manner. This is a
@@ -2824,6 +2873,26 @@ static void check_flags(unsigned long flags)
2824#endif 2873#endif
2825} 2874}
2826 2875
2876void
2877lock_set_subclass(struct lockdep_map *lock,
2878 unsigned int subclass, unsigned long ip)
2879{
2880 unsigned long flags;
2881
2882 if (unlikely(current->lockdep_recursion))
2883 return;
2884
2885 raw_local_irq_save(flags);
2886 current->lockdep_recursion = 1;
2887 check_flags(flags);
2888 if (__lock_set_subclass(lock, subclass, ip))
2889 check_chain_key(current);
2890 current->lockdep_recursion = 0;
2891 raw_local_irq_restore(flags);
2892}
2893
2894EXPORT_SYMBOL_GPL(lock_set_subclass);
2895
2827/* 2896/*
2828 * We are not always called with irqs disabled - do that here, 2897 * We are not always called with irqs disabled - do that here,
2829 * and also avoid lockdep recursion: 2898 * and also avoid lockdep recursion: