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Subject[PATCH v2 19/19] locking/lockdep: Change if to else-if when checking bfs errors
Date
After BFS searching, we check whether there is an error. These checks are
exclusive, so we can use "else if" instead of "if", which results in a bit
optimized code.

No functional change.

Signed-off-by: Yuyang Du <duyuyang@gmail.com>
---
kernel/locking/lockdep.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 1d38bf6..3efc00e 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1950,21 +1950,21 @@ static void print_lock_class_header(struct lock_class *class, int depth)

this.class = hlock_class(prev);
ret = find_usage_backwards(&this, bit_backwards, &target_entry);
- if (ret < 0) {
+ if (unlikely(ret < 0)) {
print_bfs_bug(ret);
return 0;
}
- if (ret == 1)
+ else if (ret == 1)
return ret;

that.parent = NULL;
that.class = hlock_class(next);
ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
- if (ret < 0) {
+ if (unlikely(ret < 0)) {
print_bfs_bug(ret);
return 0;
}
- if (ret == 1)
+ else if (ret == 1)
return ret;

print_bad_irq_dependency(curr, &this, &that,
@@ -2282,7 +2282,7 @@ static void print_deadlock_scenario(struct held_lock *nxt,
debug_atomic_inc(nr_redundant);
return 2;
}
- if (ret < 0) {
+ else if (unlikely(ret < 0)) {
print_bfs_bug(ret);
return 0;
}
@@ -2967,11 +2967,11 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
root.parent = NULL;
root.class = hlock_class(this);
ret = find_usage_forwards(&root, bit, &target_entry);
- if (ret < 0) {
+ if (unlikely(ret < 0)) {
print_bfs_bug(ret);
return 0;
}
- if (ret == 1)
+ else if (ret == 1)
return ret;

print_irq_inversion_bug(curr, &root, target_entry,
@@ -2994,11 +2994,11 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
root.parent = NULL;
root.class = hlock_class(this);
ret = find_usage_backwards(&root, bit, &target_entry);
- if (ret < 0) {
+ if (unlikely(ret < 0)) {
print_bfs_bug(ret);
return 0;
}
- if (ret == 1)
+ else if (ret == 1)
return ret;

print_irq_inversion_bug(curr, &root, target_entry,
--
1.8.3.1
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