[tip:locking/core] locking/lockdep: Factor out the find_held_lock() helper function

tip-bot for J. R. Okajima
2017-03-16T11:25:46Z

Commit-ID: 41c2c5b86a5e1a691ddacfc03b631b87a0b19043
Gitweb: http://git.kernel.org/tip/41c2c5b86a5e1a691ddacfc03b631b87a0b19043
Author: J. R. Okajima <hooanon05g@gmail.com>
AuthorDate: Fri, 3 Feb 2017 01:38:15 +0900
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 16 Mar 2017 09:57:06 +0100

locking/lockdep: Factor out the find_held_lock() helper function

A simple consolidataion to factor out repeated patterns.

The behaviour should not change.

Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1486053497-9948-1-git-send-email-hooanon05g@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/locking/lockdep.c | 114 ++++++++++++++++++++++-------------------------
1 file changed, 54 insertions(+), 60 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index a95e5d1..0d28b82 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3437,13 +3437,49 @@ static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
return 0;
}

+/* @depth must not be zero */
+static struct held_lock *find_held_lock(struct task_struct *curr,
+ struct lockdep_map *lock,
+ unsigned int depth, int *idx)
+{
+ struct held_lock *ret, *hlock, *prev_hlock;
+ int i;
+
+ i = depth - 1;
+ hlock = curr->held_locks + i;
+ ret = hlock;
+ if (match_held_lock(hlock, lock))
+ goto out;
+
+ ret = NULL;
+ for (i--, prev_hlock = hlock--;
+ i >= 0;
+ i--, prev_hlock = hlock--) {
+ /*
+ * We must not cross into another context:
+ */
+ if (prev_hlock->irq_context != hlock->irq_context) {
+ ret = NULL;
+ break;
+ }
+ if (match_held_lock(hlock, lock)) {
+ ret = hlock;
+ break;
+ }
+ }
+
+out:
+ *idx = i;
+ return ret;
+}
+
static int
__lock_set_class(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, unsigned int subclass,
unsigned long ip)
{
struct task_struct *curr = current;
- struct held_lock *hlock, *prev_hlock;
+ struct held_lock *hlock;
struct lock_class *class;
unsigned int depth;
int i;
@@ -3456,21 +3492,10 @@ __lock_set_class(struct lockdep_map *lock, const char *name,
if (DEBUG_LOCKS_WARN_ON(!depth))
return 0;

- prev_hlock = NULL;
- for (i = depth-1; i >= 0; i--) {
- hlock = curr->held_locks + i;
- /*
- * We must not cross into another context:
- */
- if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
- break;
- if (match_held_lock(hlock, lock))
- goto found_it;
- prev_hlock = hlock;
- }
- return print_unlock_imbalance_bug(curr, lock, ip);
+ hlock = find_held_lock(curr, lock, depth, &i);
+ if (!hlock)
+ return print_unlock_imbalance_bug(curr, lock, ip);

-found_it:
lockdep_init_map(lock, name, key, 0);
class = register_lock_class(lock, subclass, 0);
hlock->class_idx = class - lock_classes + 1;
@@ -3508,7 +3533,7 @@ static int
__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
{
struct task_struct *curr = current;
- struct held_lock *hlock, *prev_hlock;
+ struct held_lock *hlock;
unsigned int depth;
int i;

@@ -3527,21 +3552,10 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
* Check whether the lock exists in the current stack
* of held locks:
*/
- prev_hlock = NULL;
- for (i = depth-1; i >= 0; i--) {
- hlock = curr->held_locks + i;
- /*
- * We must not cross into another context:
- */
- if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
- break;
- if (match_held_lock(hlock, lock))
- goto found_it;
- prev_hlock = hlock;
- }
- return print_unlock_imbalance_bug(curr, lock, ip);
+ hlock = find_held_lock(curr, lock, depth, &i);
+ if (!hlock)
+ return print_unlock_imbalance_bug(curr, lock, ip);

-found_it:
if (hlock->instance == lock)
lock_release_holdtime(hlock);

@@ -3903,7 +3917,7 @@ static void
__lock_contended(struct lockdep_map *lock, unsigned long ip)
{
struct task_struct *curr = current;
- struct held_lock *hlock, *prev_hlock;
+ struct held_lock *hlock;
struct lock_class_stats *stats;
unsigned int depth;
int i, contention_point, contending_point;
@@ -3916,22 +3930,12 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip)
if (DEBUG_LOCKS_WARN_ON(!depth))
return;

- prev_hlock = NULL;
- for (i = depth-1; i >= 0; i--) {
- hlock = curr->held_locks + i;
- /*
- * We must not cross into another context:
- */
- if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
- break;
- if (match_held_lock(hlock, lock))
- goto found_it;
- prev_hlock = hlock;
+ hlock = find_held_lock(curr, lock, depth, &i);
+ if (!hlock) {
+ print_lock_contention_bug(curr, lock, ip);
+ return;
}
- print_lock_contention_bug(curr, lock, ip);
- return;

-found_it:
if (hlock->instance != lock)
return;

@@ -3955,7 +3959,7 @@ static void
__lock_acquired(struct lockdep_map *lock, unsigned long ip)
{
struct task_struct *curr = current;
- struct held_lock *hlock, *prev_hlock;
+ struct held_lock *hlock;
struct lock_class_stats *stats;
unsigned int depth;
u64 now, waittime = 0;
@@ -3969,22 +3973,12 @@ __lock_acquired(struct lockdep_map *lock, unsigned long ip)
if (DEBUG_LOCKS_WARN_ON(!depth))
return;

- prev_hlock = NULL;
- for (i = depth-1; i >= 0; i--) {
- hlock = curr->held_locks + i;
- /*
- * We must not cross into another context:
- */
- if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
- break;
- if (match_held_lock(hlock, lock))
- goto found_it;
- prev_hlock = hlock;
+ hlock = find_held_lock(curr, lock, depth, &i);
+ if (!hlock) {
+ print_lock_contention_bug(curr, lock, _RET_IP_);
+ return;
}
- print_lock_contention_bug(curr, lock, _RET_IP_);
- return;

-found_it:
if (hlock->instance != lock)
return;