Merge tag 'lockdep-for-tip.2025.07.16' of git://git.kernel.org/pub/scm/linux/kernel/git/boqun/linux into locking/core

Locking changes for v6.17:

- General
  - Mark devm_mutex_init() as __must_check
  - Add #[must_use] to Lock::try_lock()
  - Remove OWNER_SPINNABLE in rwsem
  - Remove redundant #ifdefs in mutex
- Lockdep
  - Avoid returning struct in lock_stats()
  - Change `static const` into enum for LOCKF_*_IRQ_*
  - Temporarily use synchronize_rcu_expedited() in
    lockdep_unregister_key() to speed things up.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>

5 files changed, 34 insertions, 33 deletions

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index dd2bbf73718b..2d4c5bab5af8 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -297,33 +297,30 @@ static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
 	dst->nr += src->nr;
 }
 
-struct lock_class_stats lock_stats(struct lock_class *class)
+void lock_stats(struct lock_class *class, struct lock_class_stats *stats)
 {
-	struct lock_class_stats stats;
 	int cpu, i;
 
-	memset(&stats, 0, sizeof(struct lock_class_stats));
+	memset(stats, 0, sizeof(struct lock_class_stats));
 	for_each_possible_cpu(cpu) {
 		struct lock_class_stats *pcs =
 			&per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
 
-		for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
-			stats.contention_point[i] += pcs->contention_point[i];
+		for (i = 0; i < ARRAY_SIZE(stats->contention_point); i++)
+			stats->contention_point[i] += pcs->contention_point[i];
 
-		for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
-			stats.contending_point[i] += pcs->contending_point[i];
+		for (i = 0; i < ARRAY_SIZE(stats->contending_point); i++)
+			stats->contending_point[i] += pcs->contending_point[i];
 
-		lock_time_add(&pcs->read_waittime, &stats.read_waittime);
-		lock_time_add(&pcs->write_waittime, &stats.write_waittime);
+		lock_time_add(&pcs->read_waittime, &stats->read_waittime);
+		lock_time_add(&pcs->write_waittime, &stats->write_waittime);
 
-		lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
-		lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
+		lock_time_add(&pcs->read_holdtime, &stats->read_holdtime);
+		lock_time_add(&pcs->write_holdtime, &stats->write_holdtime);
 
-		for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
-			stats.bounces[i] += pcs->bounces[i];
+		for (i = 0; i < ARRAY_SIZE(stats->bounces); i++)
+			stats->bounces[i] += pcs->bounces[i];
 	}
-
-	return stats;
 }
 
 void clear_lock_stats(struct lock_class *class)
@@ -6619,8 +6616,16 @@ void lockdep_unregister_key(struct lock_class_key *key)
 	if (need_callback)
 		call_rcu(&delayed_free.rcu_head, free_zapped_rcu);
 
-	/* Wait until is_dynamic_key() has finished accessing k->hash_entry. */
-	synchronize_rcu();
+	/*
+	 * Wait until is_dynamic_key() has finished accessing k->hash_entry.
+	 *
+	 * Some operations like __qdisc_destroy() will call this in a debug
+	 * kernel, and the network traffic is disabled while waiting, hence
+	 * the delay of the wait matters in debugging cases. Currently use a
+	 * synchronize_rcu_expedited() to speed up the wait at the cost of
+	 * system IPIs. TODO: Replace RCU with hazptr for this.
+	 */
+	synchronize_rcu_expedited();
 }
 EXPORT_SYMBOL_GPL(lockdep_unregister_key);
 
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index 82156caf77d1..0e5e6ffe91a3 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -47,29 +47,31 @@ enum {
 	__LOCKF(USED_READ)
 };
 
+enum {
 #define LOCKDEP_STATE(__STATE)	LOCKF_ENABLED_##__STATE |
-static const unsigned long LOCKF_ENABLED_IRQ =
+	LOCKF_ENABLED_IRQ =
 #include "lockdep_states.h"
-	0;
+	0,
 #undef LOCKDEP_STATE
 
 #define LOCKDEP_STATE(__STATE)	LOCKF_USED_IN_##__STATE |
-static const unsigned long LOCKF_USED_IN_IRQ =
+	LOCKF_USED_IN_IRQ =
 #include "lockdep_states.h"
-	0;
+	0,
 #undef LOCKDEP_STATE
 
 #define LOCKDEP_STATE(__STATE)	LOCKF_ENABLED_##__STATE##_READ |
-static const unsigned long LOCKF_ENABLED_IRQ_READ =
+	LOCKF_ENABLED_IRQ_READ =
 #include "lockdep_states.h"
-	0;
+	0,
 #undef LOCKDEP_STATE
 
 #define LOCKDEP_STATE(__STATE)	LOCKF_USED_IN_##__STATE##_READ |
-static const unsigned long LOCKF_USED_IN_IRQ_READ =
+	LOCKF_USED_IN_IRQ_READ =
 #include "lockdep_states.h"
-	0;
+	0,
 #undef LOCKDEP_STATE
+};
 
 #define LOCKF_ENABLED_IRQ_ALL (LOCKF_ENABLED_IRQ | LOCKF_ENABLED_IRQ_READ)
 #define LOCKF_USED_IN_IRQ_ALL (LOCKF_USED_IN_IRQ | LOCKF_USED_IN_IRQ_READ)
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index b52c07c4707c..1916db9aa46b 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -657,7 +657,7 @@ static int lock_stat_open(struct inode *inode, struct file *file)
 			if (!test_bit(idx, lock_classes_in_use))
 				continue;
 			iter->class = class;
-			iter->stats = lock_stats(class);
+			lock_stats(class, &iter->stats);
 			iter++;
 		}
 
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index a39ecccbd106..d4210dc97b6a 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -191,9 +191,7 @@ static void
 __mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
 		   struct list_head *list)
 {
-#ifdef CONFIG_DETECT_HUNG_TASK_BLOCKER
 	hung_task_set_blocker(lock, BLOCKER_TYPE_MUTEX);
-#endif
 	debug_mutex_add_waiter(lock, waiter, current);
 
 	list_add_tail(&waiter->list, list);
@@ -209,9 +207,7 @@ __mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter)
 		__mutex_clear_flag(lock, MUTEX_FLAGS);
 
 	debug_mutex_remove_waiter(lock, waiter, current);
-#ifdef CONFIG_DETECT_HUNG_TASK_BLOCKER
 	hung_task_clear_blocker();
-#endif
 }
 
 /*
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 2ddb827e3bea..8572dba95af4 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -727,8 +727,6 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
 	return ret;
 }
 
-#define OWNER_SPINNABLE		(OWNER_NULL | OWNER_WRITER | OWNER_READER)
-
 static inline enum owner_state
 rwsem_owner_state(struct task_struct *owner, unsigned long flags)
 {
@@ -835,7 +833,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
 		enum owner_state owner_state;
 
 		owner_state = rwsem_spin_on_owner(sem);
-		if (!(owner_state & OWNER_SPINNABLE))
+		if (owner_state == OWNER_NONSPINNABLE)
 			break;
 
 		/*