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

Pull locking updates from Ingo Molnar: "The main change in this cycle are initial preparatory bits of dynamic lockdep keys support from Bart Van Assche. There are also misc changes, a comment cleanup and a data structure cleanup" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/fair: Clean up comment in nohz_idle_balance() locking/lockdep: Stop using RCU primitives to access 'all_lock_classes' locking/lockdep: Make concurrent lockdep_reset_lock() calls safe locking/lockdep: Remove a superfluous INIT_LIST_HEAD() statement locking/lockdep: Introduce lock_class_cache_is_registered() locking/lockdep: Inline __lockdep_init_map() locking/lockdep: Declare local symbols static tools/lib/lockdep/tests: Test the lockdep_reset_lock() implementation tools/lib/lockdep: Add dummy print_irqtrace_events() implementation tools/lib/lockdep: Rename "trywlock" into "trywrlock" tools/lib/lockdep/tests: Run lockdep tests a second time under Valgrind tools/lib/lockdep/tests: Improve testing accuracy tools/lib/lockdep/tests: Fix shellcheck warnings tools/lib/lockdep/tests: Display compiler warning and error messages locking/lockdep: Remove ::version from lock_class structure

Linus Torvalds committed 7 years ago

Commit 1eefdec2 parents 684019d 80eb86526 files · +131 −53Browse files

Showing the changes to kernel/locking (1 of 26 files). Show all

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kernel/locking/lockdep.c+43−33
@@ -138,6 +138,9 @@ static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; · 137 unmodified lines
138138 * get freed - this significantly simplifies the debugging code.
139139 */
140140 unsigned long nr_lock_classes;
141+#ifndef CONFIG_DEBUG_LOCKDEP
142+static
143+#endif
141144 struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
142145
143146 static inline struct lock_class *hlock_class(struct held_lock *hlock)
@@ -626,7 +629,8 @@ static int static_obj(void *obj) · 482 unmodified lines
626629
627630 /*
628631 * To make lock name printouts unique, we calculate a unique
629− * class->name_version generation counter:
632+ * class->name_version generation counter. The caller must hold the graph
633+ * lock.
630634 */
631635 static int count_matching_names(struct lock_class *new_class)
632636 {
@@ -636,7 +640,7 @@ static int count_matching_names(struct lock_class *new_class) · 3 unmodified lines
636640 if (!new_class->name)
637641 return 0;
638642
639− list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) {
643+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
640644 if (new_class->key - new_class->subclass == class->key)
641645 return class->name_version;
642646 if (class->name && !strcmp(class->name, new_class->name))
@@ -789,7 +793,6 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) · 146 unmodified lines
789793 class->key = key;
790794 class->name = lock->name;
791795 class->subclass = subclass;
792− INIT_LIST_HEAD(&class->lock_entry);
793796 INIT_LIST_HEAD(&class->locks_before);
794797 INIT_LIST_HEAD(&class->locks_after);
795798 class->name_version = count_matching_names(class);
@@ -801,7 +804,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) · 5 unmodified lines
801804 /*
802805 * Add it to the global list of classes:
803806 */
804− list_add_tail_rcu(&class->lock_entry, &all_lock_classes);
807+ list_add_tail(&class->lock_entry, &all_lock_classes);
805808
806809 if (verbose(class)) {
807810 graph_unlock();
@@ -3088,7 +3091,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, · 2280 unmodified lines
30883091 /*
30893092 * Initialize a lock instance's lock-class mapping info:
30903093 */
3091−static void __lockdep_init_map(struct lockdep_map *lock, const char *name,
3094+void lockdep_init_map(struct lockdep_map *lock, const char *name,
30923095 struct lock_class_key *key, int subclass)
30933096 {
30943097 int i;
@@ -3144,12 +3147,6 @@ static void __lockdep_init_map(struct lockdep_map *lock, const char *name, · 49 unmodified lines
31443147 raw_local_irq_restore(flags);
31453148 }
31463149 }
3147−
3148−void lockdep_init_map(struct lockdep_map *lock, const char *name,
3149− struct lock_class_key *key, int subclass)
3150−{
3151− __lockdep_init_map(lock, name, key, subclass);
3152−}
31533150 EXPORT_SYMBOL_GPL(lockdep_init_map);
31543151
31553152 struct lock_class_key __lockdep_no_validate__;
@@ -4126,6 +4123,9 @@ void lockdep_reset(void) · 970 unmodified lines
41264123 raw_local_irq_restore(flags);
41274124 }
41284125
4126+/*
4127+ * Remove all references to a lock class. The caller must hold the graph lock.
4128+ */
41294129 static void zap_class(struct lock_class *class)
41304130 {
41314131 int i;
@@ -4142,7 +4142,7 @@ static void zap_class(struct lock_class *class) · 10 unmodified lines
41424142 * Unhash the class and remove it from the all_lock_classes list:
41434143 */
41444144 hlist_del_rcu(&class->hash_entry);
4145− list_del_rcu(&class->lock_entry);
4145+ list_del(&class->lock_entry);
41464146
41474147 RCU_INIT_POINTER(class->key, NULL);
41484148 RCU_INIT_POINTER(class->name, NULL);
@@ -4204,15 +4204,36 @@ void lockdep_free_key_range(void *start, unsigned long size) · 55 unmodified lines
42044204 */
42054205 }
42064206
4207−void lockdep_reset_lock(struct lockdep_map *lock)
4207+/*
4208+ * Check whether any element of the @lock->class_cache[] array refers to a
4209+ * registered lock class. The caller must hold either the graph lock or the
4210+ * RCU read lock.
4211+ */
4212+static bool lock_class_cache_is_registered(struct lockdep_map *lock)
42084213 {
42094214 struct lock_class *class;
42104215 struct hlist_head *head;
4211− unsigned long flags;
42124216 int i, j;
4213− int locked;
4217+
4218+ for (i = 0; i < CLASSHASH_SIZE; i++) {
4219+ head = classhash_table + i;
4220+ hlist_for_each_entry_rcu(class, head, hash_entry) {
4221+ for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
4222+ if (lock->class_cache[j] == class)
4223+ return true;
4224+ }
4225+ }
4226+ return false;
4227+}
4228+
4229+void lockdep_reset_lock(struct lockdep_map *lock)
4230+{
4231+ struct lock_class *class;
4232+ unsigned long flags;
4233+ int j, locked;
42144234
42154235 raw_local_irq_save(flags);
4236+ locked = graph_lock();
42164237
42174238 /*
42184239 * Remove all classes this lock might have:
@@ -4229,25 +4250,14 @@ void lockdep_reset_lock(struct lockdep_map *lock) · 10 unmodified lines
42294250 * Debug check: in the end all mapped classes should
42304251 * be gone.
42314252 */
4232− locked = graph_lock();
4233− for (i = 0; i < CLASSHASH_SIZE; i++) {
4234− head = classhash_table + i;
4235− hlist_for_each_entry_rcu(class, head, hash_entry) {
4236− int match = 0;
4237−
4238− for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
4239− match |= class == lock->class_cache[j];
4240−
4241− if (unlikely(match)) {
4242− if (debug_locks_off_graph_unlock()) {
4243− /*
4244− * We all just reset everything, how did it match?
4245− */
4246− WARN_ON(1);
4247− }
4248− goto out_restore;
4249− }
4253+ if (unlikely(lock_class_cache_is_registered(lock))) {
4254+ if (debug_locks_off_graph_unlock()) {
4255+ /*
4256+ * We all just reset everything, how did it match?
4257+ */
4258+ WARN_ON(1);
42504259 }
4260+ goto out_restore;
42514261 }
42524262 if (locked)
42534263 graph_unlock();