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locking/lockdep: Add a skip() function to __bfs() 

Some __bfs() walks will have additional iteration constraints (beyond
the path being strong). Provide an additional function to allow
terminating graph walks.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
This commit is contained in:
Boqun Feng 2020-12-10 11:02:40 +01:00 committed by Peter Zijlstra
parent dfd5e3f5fe
commit bc2dd71b28
1 changed files with 19 additions and 10 deletions
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29
kernel/locking/lockdep.c
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@ -1672,6 +1672,7 @@ static inline struct lock_list *__bfs_next(struct lock_list *lock, int offset)
static enum bfs_result __bfs(struct lock_list *source_entry, static enum bfs_result __bfs(struct lock_list *source_entry,
void *data, void *data,
bool (*match)(struct lock_list *entry, void *data), bool (*match)(struct lock_list *entry, void *data),
bool (*skip)(struct lock_list *entry, void *data),
struct lock_list **target_entry, struct lock_list **target_entry,
int offset) int offset)
{ {
@ -1732,7 +1733,12 @@ static enum bfs_result __bfs(struct lock_list *source_entry,
/* /*
* Step 3: we haven't visited this and there is a strong * Step 3: we haven't visited this and there is a strong
* dependency path to this, so check with @match. * dependency path to this, so check with @match.
* If @skip is provide and returns true, we skip this
* lock (and any path this lock is in).
*/ */
if (skip && skip(lock, data))
continue;
if (match(lock, data)) { if (match(lock, data)) {
*target_entry = lock; *target_entry = lock;
return BFS_RMATCH; return BFS_RMATCH;
@ -1775,9 +1781,10 @@ static inline enum bfs_result
__bfs_forwards(struct lock_list *src_entry, __bfs_forwards(struct lock_list *src_entry,
void *data, void *data,
bool (*match)(struct lock_list *entry, void *data), bool (*match)(struct lock_list *entry, void *data),
bool (*skip)(struct lock_list *entry, void *data),
struct lock_list **target_entry) struct lock_list **target_entry)
{ {
return __bfs(src_entry, data, match, target_entry, return __bfs(src_entry, data, match, skip, target_entry,
offsetof(struct lock_class, locks_after)); offsetof(struct lock_class, locks_after));
} }
@ -1786,9 +1793,10 @@ static inline enum bfs_result
__bfs_backwards(struct lock_list *src_entry, __bfs_backwards(struct lock_list *src_entry,
void *data, void *data,
bool (*match)(struct lock_list *entry, void *data), bool (*match)(struct lock_list *entry, void *data),
bool (*skip)(struct lock_list *entry, void *data),
struct lock_list **target_entry) struct lock_list **target_entry)
{ {
return __bfs(src_entry, data, match, target_entry, return __bfs(src_entry, data, match, skip, target_entry,
offsetof(struct lock_class, locks_before)); offsetof(struct lock_class, locks_before));
} }
@ -2019,7 +2027,7 @@ static unsigned long __lockdep_count_forward_deps(struct lock_list *this)
unsigned long count = 0; unsigned long count = 0;
struct lock_list *target_entry; struct lock_list *target_entry;
__bfs_forwards(this, (void *)&count, noop_count, &target_entry); __bfs_forwards(this, (void *)&count, noop_count, NULL, &target_entry);
return count; return count;
} }
@ -2044,7 +2052,7 @@ static unsigned long __lockdep_count_backward_deps(struct lock_list *this)
unsigned long count = 0; unsigned long count = 0;
struct lock_list *target_entry; struct lock_list *target_entry;
__bfs_backwards(this, (void *)&count, noop_count, &target_entry); __bfs_backwards(this, (void *)&count, noop_count, NULL, &target_entry);
return count; return count;
} }
@ -2072,11 +2080,12 @@ unsigned long lockdep_count_backward_deps(struct lock_class *class)
static noinline enum bfs_result static noinline enum bfs_result
check_path(struct held_lock *target, struct lock_list *src_entry, check_path(struct held_lock *target, struct lock_list *src_entry,
bool (*match)(struct lock_list *entry, void *data), bool (*match)(struct lock_list *entry, void *data),
bool (*skip)(struct lock_list *entry, void *data),
struct lock_list **target_entry) struct lock_list **target_entry)
{ {
enum bfs_result ret; enum bfs_result ret;
ret = __bfs_forwards(src_entry, target, match, target_entry); ret = __bfs_forwards(src_entry, target, match, skip, target_entry);
if (unlikely(bfs_error(ret))) if (unlikely(bfs_error(ret)))
print_bfs_bug(ret); print_bfs_bug(ret);
@ -2103,7 +2112,7 @@ check_noncircular(struct held_lock *src, struct held_lock *target,
debug_atomic_inc(nr_cyclic_checks); debug_atomic_inc(nr_cyclic_checks);
ret = check_path(target, &src_entry, hlock_conflict, &target_entry); ret = check_path(target, &src_entry, hlock_conflict, NULL, &target_entry);
if (unlikely(ret == BFS_RMATCH)) { if (unlikely(ret == BFS_RMATCH)) {
if (!*trace) { if (!*trace) {
@ -2152,7 +2161,7 @@ check_redundant(struct held_lock *src, struct held_lock *target)
debug_atomic_inc(nr_redundant_checks); debug_atomic_inc(nr_redundant_checks);
ret = check_path(target, &src_entry, hlock_equal, &target_entry); ret = check_path(target, &src_entry, hlock_equal, NULL, &target_entry);
if (ret == BFS_RMATCH) if (ret == BFS_RMATCH)
debug_atomic_inc(nr_redundant); debug_atomic_inc(nr_redundant);
@ -2246,7 +2255,7 @@ find_usage_forwards(struct lock_list *root, unsigned long usage_mask,
debug_atomic_inc(nr_find_usage_forwards_checks); debug_atomic_inc(nr_find_usage_forwards_checks);
result = __bfs_forwards(root, &usage_mask, usage_match, target_entry); result = __bfs_forwards(root, &usage_mask, usage_match, NULL, target_entry);
return result; return result;
} }
@ -2263,7 +2272,7 @@ find_usage_backwards(struct lock_list *root, unsigned long usage_mask,
debug_atomic_inc(nr_find_usage_backwards_checks); debug_atomic_inc(nr_find_usage_backwards_checks);
result = __bfs_backwards(root, &usage_mask, usage_match, target_entry); result = __bfs_backwards(root, &usage_mask, usage_match, NULL, target_entry);
return result; return result;
} }
@ -2628,7 +2637,7 @@ static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
*/ */
bfs_init_rootb(&this, prev); bfs_init_rootb(&this, prev);
ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, NULL); ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, NULL, NULL);
if (bfs_error(ret)) { if (bfs_error(ret)) {
print_bfs_bug(ret); print_bfs_bug(ret);
return 0; return 0;