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authorLinus Torvalds <torvalds@linux-foundation.org>2018-12-26 14:25:52 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-26 14:25:52 -0800
commit1eefdec18eded41833401cfd64749643ff72e7da (patch)
treecf9d35939e239b7d1ed3194bec7f4d51409c2d50 /kernel/locking
parent684019dd1f0092b4ffce4958c84aff0891deac83 (diff)
parent80eb865768703c0f85a0603762742ae1dedf21f0 (diff)
downloadlinux-1eefdec18eded41833401cfd64749643ff72e7da.tar.bz2
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
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/lockdep.c76
1 files changed, 43 insertions, 33 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index ef27f98714c0..95932333a48b 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -138,6 +138,9 @@ static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
* get freed - this significantly simplifies the debugging code.
*/
unsigned long nr_lock_classes;
+#ifndef CONFIG_DEBUG_LOCKDEP
+static
+#endif
struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
static inline struct lock_class *hlock_class(struct held_lock *hlock)
@@ -626,7 +629,8 @@ static int static_obj(void *obj)
/*
* To make lock name printouts unique, we calculate a unique
- * class->name_version generation counter:
+ * class->name_version generation counter. The caller must hold the graph
+ * lock.
*/
static int count_matching_names(struct lock_class *new_class)
{
@@ -636,7 +640,7 @@ static int count_matching_names(struct lock_class *new_class)
if (!new_class->name)
return 0;
- list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) {
+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
if (new_class->key - new_class->subclass == class->key)
return class->name_version;
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)
class->key = key;
class->name = lock->name;
class->subclass = subclass;
- INIT_LIST_HEAD(&class->lock_entry);
INIT_LIST_HEAD(&class->locks_before);
INIT_LIST_HEAD(&class->locks_after);
class->name_version = count_matching_names(class);
@@ -801,7 +804,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
/*
* Add it to the global list of classes:
*/
- list_add_tail_rcu(&class->lock_entry, &all_lock_classes);
+ list_add_tail(&class->lock_entry, &all_lock_classes);
if (verbose(class)) {
graph_unlock();
@@ -3088,7 +3091,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
/*
* Initialize a lock instance's lock-class mapping info:
*/
-static void __lockdep_init_map(struct lockdep_map *lock, const char *name,
+void lockdep_init_map(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, int subclass)
{
int i;
@@ -3144,12 +3147,6 @@ static void __lockdep_init_map(struct lockdep_map *lock, const char *name,
raw_local_irq_restore(flags);
}
}
-
-void lockdep_init_map(struct lockdep_map *lock, const char *name,
- struct lock_class_key *key, int subclass)
-{
- __lockdep_init_map(lock, name, key, subclass);
-}
EXPORT_SYMBOL_GPL(lockdep_init_map);
struct lock_class_key __lockdep_no_validate__;
@@ -4126,6 +4123,9 @@ void lockdep_reset(void)
raw_local_irq_restore(flags);
}
+/*
+ * Remove all references to a lock class. The caller must hold the graph lock.
+ */
static void zap_class(struct lock_class *class)
{
int i;
@@ -4142,7 +4142,7 @@ static void zap_class(struct lock_class *class)
* Unhash the class and remove it from the all_lock_classes list:
*/
hlist_del_rcu(&class->hash_entry);
- list_del_rcu(&class->lock_entry);
+ list_del(&class->lock_entry);
RCU_INIT_POINTER(class->key, NULL);
RCU_INIT_POINTER(class->name, NULL);
@@ -4204,15 +4204,36 @@ 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);
+ locked = graph_lock();
/*
* Remove all classes this lock might have:
@@ -4229,25 +4250,14 @@ void lockdep_reset_lock(struct lockdep_map *lock)
* Debug check: in the end all mapped classes should
* 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();