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Diffstat (limited to 'kernel/lockdep.c')
-rw-r--r--kernel/lockdep.c136
1 files changed, 69 insertions, 67 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index f32ca78c198..9bad1788451 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -169,22 +169,17 @@ EXPORT_SYMBOL(lockdep_internal);
*/
static int class_filter(struct lock_class *class)
{
+#if 0
+ /* Example */
if (class->name_version == 1 &&
- !strcmp(class->name, "&rl->lock"))
+ !strcmp(class->name, "lockname"))
return 1;
if (class->name_version == 1 &&
- !strcmp(class->name, "&ni->mrec_lock"))
+ !strcmp(class->name, "&struct->lockfield"))
return 1;
- if (class->name_version == 1 &&
- !strcmp(class->name, "mft_ni_runlist_lock"))
- return 1;
- if (class->name_version == 1 &&
- !strcmp(class->name, "mft_ni_mrec_lock"))
- return 1;
- if (class->name_version == 1 &&
- !strcmp(class->name, "&vol->lcnbmp_lock"))
- return 1;
- return 0;
+#endif
+ /* Allow everything else. 0 would be filter everything else */
+ return 1;
}
#endif
@@ -408,23 +403,12 @@ static void lockdep_print_held_locks(struct task_struct *curr)
print_lock(curr->held_locks + i);
}
}
-/*
- * Helper to print a nice hierarchy of lock dependencies:
- */
-static void print_spaces(int nr)
-{
- int i;
-
- for (i = 0; i < nr; i++)
- printk(" ");
-}
static void print_lock_class_header(struct lock_class *class, int depth)
{
int bit;
- print_spaces(depth);
- printk("->");
+ printk("%*s->", depth, "");
print_lock_name(class);
printk(" ops: %lu", class->ops);
printk(" {\n");
@@ -433,17 +417,14 @@ static void print_lock_class_header(struct lock_class *class, int depth)
if (class->usage_mask & (1 << bit)) {
int len = depth;
- print_spaces(depth);
- len += printk(" %s", usage_str[bit]);
+ len += printk("%*s %s", depth, "", usage_str[bit]);
len += printk(" at:\n");
print_stack_trace(class->usage_traces + bit, len);
}
}
- print_spaces(depth);
- printk(" }\n");
+ printk("%*s }\n", depth, "");
- print_spaces(depth);
- printk(" ... key at: ");
+ printk("%*s ... key at: ",depth,"");
print_ip_sym((unsigned long)class->key);
}
@@ -463,8 +444,7 @@ static void print_lock_dependencies(struct lock_class *class, int depth)
DEBUG_LOCKS_WARN_ON(!entry->class);
print_lock_dependencies(entry->class, depth + 1);
- print_spaces(depth);
- printk(" ... acquired at:\n");
+ printk("%*s ... acquired at:\n",depth,"");
print_stack_trace(&entry->trace, 2);
printk("\n");
}
@@ -1124,7 +1104,7 @@ extern void __error_too_big_MAX_LOCKDEP_SUBCLASSES(void);
* itself, so actual lookup of the hash should be once per lock object.
*/
static inline struct lock_class *
-register_lock_class(struct lockdep_map *lock, unsigned int subclass)
+look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
{
struct lockdep_subclass_key *key;
struct list_head *hash_head;
@@ -1168,7 +1148,26 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass)
*/
list_for_each_entry(class, hash_head, hash_entry)
if (class->key == key)
- goto out_set;
+ return class;
+
+ return NULL;
+}
+
+/*
+ * Register a lock's class in the hash-table, if the class is not present
+ * yet. Otherwise we look it up. We cache the result in the lock object
+ * itself, so actual lookup of the hash should be once per lock object.
+ */
+static inline struct lock_class *
+register_lock_class(struct lockdep_map *lock, unsigned int subclass)
+{
+ struct lockdep_subclass_key *key;
+ struct list_head *hash_head;
+ struct lock_class *class;
+
+ class = look_up_lock_class(lock, subclass);
+ if (likely(class))
+ return class;
/*
* Debug-check: all keys must be persistent!
@@ -1183,6 +1182,9 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass)
return NULL;
}
+ key = lock->key->subkeys + subclass;
+ hash_head = classhashentry(key);
+
__raw_spin_lock(&hash_lock);
/*
* We have to do the hash-walk again, to avoid races
@@ -1229,8 +1231,8 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass)
out_unlock_set:
__raw_spin_unlock(&hash_lock);
-out_set:
- lock->class[subclass] = class;
+ if (!subclass)
+ lock->class_cache = class;
DEBUG_LOCKS_WARN_ON(class->subclass != subclass);
@@ -1934,7 +1936,7 @@ void lockdep_init_map(struct lockdep_map *lock, const char *name,
}
lock->name = name;
lock->key = key;
- memset(lock->class, 0, sizeof(lock->class[0])*MAX_LOCKDEP_SUBCLASSES);
+ lock->class_cache = NULL;
}
EXPORT_SYMBOL_GPL(lockdep_init_map);
@@ -1948,8 +1950,8 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
unsigned long ip)
{
struct task_struct *curr = current;
+ struct lock_class *class = NULL;
struct held_lock *hlock;
- struct lock_class *class;
unsigned int depth, id;
int chain_head = 0;
u64 chain_key;
@@ -1967,8 +1969,11 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
return 0;
}
- class = lock->class[subclass];
- /* not cached yet? */
+ if (!subclass)
+ class = lock->class_cache;
+ /*
+ * Not cached yet or subclass?
+ */
if (unlikely(!class)) {
class = register_lock_class(lock, subclass);
if (!class)
@@ -2469,48 +2474,44 @@ void lockdep_free_key_range(void *start, unsigned long size)
void lockdep_reset_lock(struct lockdep_map *lock)
{
- struct lock_class *class, *next, *entry;
+ struct lock_class *class, *next;
struct list_head *head;
unsigned long flags;
int i, j;
raw_local_irq_save(flags);
- __raw_spin_lock(&hash_lock);
/*
- * Remove all classes this lock has:
+ * Remove all classes this lock might have:
+ */
+ for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
+ /*
+ * If the class exists we look it up and zap it:
+ */
+ class = look_up_lock_class(lock, j);
+ if (class)
+ zap_class(class);
+ }
+ /*
+ * Debug check: in the end all mapped classes should
+ * be gone.
*/
+ __raw_spin_lock(&hash_lock);
for (i = 0; i < CLASSHASH_SIZE; i++) {
head = classhash_table + i;
if (list_empty(head))
continue;
list_for_each_entry_safe(class, next, head, hash_entry) {
- for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
- entry = lock->class[j];
- if (class == entry) {
- zap_class(class);
- lock->class[j] = NULL;
- break;
- }
+ if (unlikely(class == lock->class_cache)) {
+ __raw_spin_unlock(&hash_lock);
+ DEBUG_LOCKS_WARN_ON(1);
+ goto out_restore;
}
}
}
-
- /*
- * Debug check: in the end all mapped classes should
- * be gone.
- */
- for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
- entry = lock->class[j];
- if (!entry)
- continue;
- __raw_spin_unlock(&hash_lock);
- DEBUG_LOCKS_WARN_ON(1);
- raw_local_irq_restore(flags);
- return;
- }
-
__raw_spin_unlock(&hash_lock);
+
+out_restore:
raw_local_irq_restore(flags);
}
@@ -2571,7 +2572,7 @@ static inline int in_range(const void *start, const void *addr, const void *end)
static void
print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
- const void *mem_to)
+ const void *mem_to, struct held_lock *hlock)
{
if (!debug_locks_off())
return;
@@ -2583,6 +2584,7 @@ print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
printk( "-------------------------\n");
printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
curr->comm, curr->pid, mem_from, mem_to-1);
+ print_lock(hlock);
lockdep_print_held_locks(curr);
printk("\nstack backtrace:\n");
@@ -2616,7 +2618,7 @@ void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
!in_range(mem_from, lock_to, mem_to))
continue;
- print_freed_lock_bug(curr, mem_from, mem_to);
+ print_freed_lock_bug(curr, mem_from, mem_to, hlock);
break;
}
local_irq_restore(flags);