Commit-ID: 2904d9fa45d3ce7153f1e10d78c570ecf7f19c35 Gitweb: https://git.kernel.org/tip/2904d9fa45d3ce7153f1e10d78c570ecf7f19c35 Author: Bart Van Assche <bvanass...@acm.org> AuthorDate: Thu, 6 Dec 2018 17:11:34 -0800 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Tue, 11 Dec 2018 14:54:53 +0100
locking/lockdep: Introduce lock_class_cache_is_registered() This patch does not change any functionality but makes the lockdep_reset_lock() function easier to read. Signed-off-by: Bart Van Assche <bvanass...@acm.org> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Johannes Berg <johan...@sipsolutions.net> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Sasha Levin <sasha.le...@oracle.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Waiman Long <long...@redhat.com> Cc: johannes.b...@intel.com Cc: t...@kernel.org Link: https://lkml.kernel.org/r/20181207011148.251812-11-bvanass...@acm.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/locking/lockdep.c | 50 +++++++++++++++++++++++++++++------------------- 1 file changed, 30 insertions(+), 20 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index b5c8fcb6c070..81388d028ac7 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4201,13 +4201,33 @@ void lockdep_free_key_range(void *start, unsigned long size) */ } -void lockdep_reset_lock(struct lockdep_map *lock) +/* + * Check whether any element of the @lock->class_cache[] array refers to a + * registered lock class. The caller must hold either the graph lock or the + * RCU read lock. + */ +static bool lock_class_cache_is_registered(struct lockdep_map *lock) { struct lock_class *class; struct hlist_head *head; - unsigned long flags; int i, j; - int locked; + + for (i = 0; i < CLASSHASH_SIZE; i++) { + head = classhash_table + i; + hlist_for_each_entry_rcu(class, head, hash_entry) { + for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) + if (lock->class_cache[j] == class) + return true; + } + } + return false; +} + +void lockdep_reset_lock(struct lockdep_map *lock) +{ + struct lock_class *class; + unsigned long flags; + int j, locked; raw_local_irq_save(flags); @@ -4227,24 +4247,14 @@ void lockdep_reset_lock(struct lockdep_map *lock) * be gone. */ locked = graph_lock(); - for (i = 0; i < CLASSHASH_SIZE; i++) { - head = classhash_table + i; - hlist_for_each_entry_rcu(class, head, hash_entry) { - int match = 0; - - for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) - match |= class == lock->class_cache[j]; - - if (unlikely(match)) { - if (debug_locks_off_graph_unlock()) { - /* - * We all just reset everything, how did it match? - */ - WARN_ON(1); - } - goto out_restore; - } + if (unlikely(lock_class_cache_is_registered(lock))) { + if (debug_locks_off_graph_unlock()) { + /* + * We all just reset everything, how did it match? + */ + WARN_ON(1); } + goto out_restore; } if (locked) graph_unlock();
