[PATCH 1/4] locking/lockdep: Use hashtable.h for lock_keys_hash

[PATCH 1/4] locking/lockdep: Use hashtable.h for lock_keys_hash

[Sasha Levin]

Convert the lock_keys_hash array in lockdep.c to use the generic
hashtable implementation from hashtable.h instead of the manual
hlist_head array implementation.

This simplifies the code and makes it more maintainable by using the
standard hashtable API defined in hashtable.h, while preserving the
RCU-safe behavior with proper RCU variants of the hashtable functions.

Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/locking/lockdep.c | 34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 4470680f02269..160cf8310eda0 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -57,6 +57,7 @@
 #include <linux/lockdep.h>
 #include <linux/context_tracking.h>
 #include <linux/console.h>
+#include <linux/hashtable.h>
 
 #include <asm/sections.h>
 
@@ -212,8 +213,7 @@ static DECLARE_BITMAP(list_entries_in_use, MAX_LOCKDEP_ENTRIES);
  * in use.
  */
 #define KEYHASH_BITS		(MAX_LOCKDEP_KEYS_BITS - 1)
-#define KEYHASH_SIZE		(1UL << KEYHASH_BITS)
-static struct hlist_head lock_keys_hash[KEYHASH_SIZE];
+static DEFINE_HASHTABLE(lock_keys_hash, KEYHASH_BITS);
 unsigned long nr_lock_classes;
 unsigned long nr_zapped_classes;
 unsigned long max_lock_class_idx;
@@ -1209,32 +1209,28 @@ static void init_data_structures_once(void)
 	init_chain_block_buckets();
 }
 
-static inline struct hlist_head *keyhashentry(const struct lock_class_key *key)
-{
-	unsigned long hash = hash_long((uintptr_t)key, KEYHASH_BITS);
-
-	return lock_keys_hash + hash;
-}
 
 /* Register a dynamically allocated key. */
 void lockdep_register_key(struct lock_class_key *key)
 {
-	struct hlist_head *hash_head;
 	struct lock_class_key *k;
+	unsigned long hash;
 	unsigned long flags;
 
 	if (WARN_ON_ONCE(static_obj(key)))
 		return;
-	hash_head = keyhashentry(key);
+
+	hash = hash_long((uintptr_t)key, KEYHASH_BITS);
 
 	raw_local_irq_save(flags);
 	if (!graph_lock())
 		goto restore_irqs;
-	hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
+
+	hash_for_each_possible_rcu(lock_keys_hash, k, hash_entry, hash) {
 		if (WARN_ON_ONCE(k == key))
 			goto out_unlock;
 	}
-	hlist_add_head_rcu(&key->hash_entry, hash_head);
+	hash_add_rcu(lock_keys_hash, &key->hash_entry, hash);
 out_unlock:
 	graph_unlock();
 restore_irqs:
@@ -1245,8 +1241,8 @@ EXPORT_SYMBOL_GPL(lockdep_register_key);
 /* Check whether a key has been registered as a dynamic key. */
 static bool is_dynamic_key(const struct lock_class_key *key)
 {
-	struct hlist_head *hash_head;
 	struct lock_class_key *k;
+	unsigned long hash;
 	bool found = false;
 
 	if (WARN_ON_ONCE(static_obj(key)))
@@ -1260,10 +1256,10 @@ static bool is_dynamic_key(const struct lock_class_key *key)
 	if (!debug_locks)
 		return true;
 
-	hash_head = keyhashentry(key);
+	hash = hash_long((uintptr_t)key, KEYHASH_BITS);
 
 	rcu_read_lock();
-	hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
+	hash_for_each_possible_rcu(lock_keys_hash, k, hash_entry, hash) {
 		if (k == key) {
 			found = true;
 			break;
@@ -6561,9 +6557,9 @@ void lockdep_reset_lock(struct lockdep_map *lock)
  */
 void lockdep_unregister_key(struct lock_class_key *key)
 {
-	struct hlist_head *hash_head = keyhashentry(key);
 	struct lock_class_key *k;
 	struct pending_free *pf;
+	unsigned long hash;
 	unsigned long flags;
 	bool found = false;
 	bool need_callback = false;
@@ -6573,12 +6569,14 @@ void lockdep_unregister_key(struct lock_class_key *key)
 	if (WARN_ON_ONCE(static_obj(key)))
 		return;
 
+	hash = hash_long((uintptr_t)key, KEYHASH_BITS);
+
 	raw_local_irq_save(flags);
 	lockdep_lock();
 
-	hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
+	hash_for_each_possible(lock_keys_hash, k, hash_entry, hash) {
 		if (k == key) {
-			hlist_del_rcu(&k->hash_entry);
+			hash_del_rcu(&k->hash_entry);
 			found = true;
 			break;
 		}
-- 
2.39.5

[PATCH 2/4] locking/lockdep: Use hashtable.h for classhash_table

[Sasha Levin]

Convert classhash_table in lockdep.c to use the generic hashtable
implementation from hashtable.h instead of the manual hlist_head array
implementation.

This simplifies the code and makes it more maintainable by using the
standard hashtable API and removes the need for custom hash lookup
functions.

Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/locking/lockdep.c | 69 ++++++++++++++--------------------------
 1 file changed, 24 insertions(+), 45 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 160cf8310eda0..b071bbf0d955c 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -404,12 +404,8 @@ static struct delayed_free {
 /*
  * The lockdep classes are in a hash-table as well, for fast lookup:
  */
-#define CLASSHASH_BITS		(MAX_LOCKDEP_KEYS_BITS - 1)
-#define CLASSHASH_SIZE		(1UL << CLASSHASH_BITS)
-#define __classhashfn(key)	hash_long((unsigned long)key, CLASSHASH_BITS)
-#define classhashentry(key)	(classhash_table + __classhashfn((key)))
-
-static struct hlist_head classhash_table[CLASSHASH_SIZE];
+#define CLASSHASH_BITS		(MAX_LOCKDEP_KEYS_BITS-1)
+static DEFINE_HASHTABLE(classhash_table, CLASSHASH_BITS);
 
 /*
  * We put the lock dependency chains into a hash-table as well, to cache
@@ -886,8 +882,8 @@ static noinstr struct lock_class *
 look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass)
 {
 	struct lockdep_subclass_key *key;
-	struct hlist_head *hash_head;
 	struct lock_class *class;
+	unsigned long hash;
 
 	if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
 		instrumentation_begin();
@@ -920,8 +916,7 @@ look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass)
 			sizeof(struct lockdep_map));
 
 	key = lock->key->subkeys + subclass;
-
-	hash_head = classhashentry(key);
+	hash = (unsigned long)key;
 
 	/*
 	 * We do an RCU walk of the hash, see lockdep_free_key_range().
@@ -929,7 +924,7 @@ look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass)
 	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
 		return NULL;
 
-	hlist_for_each_entry_rcu_notrace(class, hash_head, hash_entry) {
+	hash_for_each_possible_rcu_notrace(classhash_table, class, hash_entry, hash) {
 		if (class->key == key) {
 			/*
 			 * Huh! same key, different name? Did someone trample
@@ -1084,7 +1079,6 @@ static bool __check_data_structures(void)
 {
 	struct lock_class *class;
 	struct lock_chain *chain;
-	struct hlist_head *head;
 	struct lock_list *e;
 	int i;
 
@@ -1110,12 +1104,9 @@ static bool __check_data_structures(void)
 	}
 
 	/* Check the chain_key of all lock chains. */
-	for (i = 0; i < ARRAY_SIZE(chainhash_table); i++) {
-		head = chainhash_table + i;
-		hlist_for_each_entry_rcu(chain, head, entry) {
-			if (!check_lock_chain_key(chain))
-				return false;
-		}
+	hash_for_each_rcu(chainhash_table, i, chain, entry) {
+		if (!check_lock_chain_key(chain))
+			return false;
 	}
 
 	/*
@@ -1279,8 +1270,8 @@ static struct lock_class *
 register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
 {
 	struct lockdep_subclass_key *key;
-	struct hlist_head *hash_head;
 	struct lock_class *class;
+	unsigned long hash;
 	int idx;
 
 	DEBUG_LOCKS_WARN_ON(!irqs_disabled());
@@ -1297,7 +1288,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
 	}
 
 	key = lock->key->subkeys + subclass;
-	hash_head = classhashentry(key);
+	hash = (unsigned long)key;
 
 	if (!graph_lock()) {
 		return NULL;
@@ -1306,7 +1297,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
 	 * We have to do the hash-walk again, to avoid races
 	 * with another CPU:
 	 */
-	hlist_for_each_entry_rcu(class, hash_head, hash_entry) {
+	hash_for_each_possible_rcu(classhash_table, class, hash_entry, hash) {
 		if (class->key == key)
 			goto out_unlock_set;
 	}
@@ -1343,7 +1334,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
 	 * We use RCU's safe list-add method to make
 	 * parallel walking of the hash-list safe:
 	 */
-	hlist_add_head_rcu(&class->hash_entry, hash_head);
+	hash_add_rcu(classhash_table, &class->hash_entry, hash);
 	/*
 	 * Remove the class from the free list and add it to the global list
 	 * of classes.
@@ -6206,14 +6197,10 @@ static void remove_class_from_lock_chains(struct pending_free *pf,
 					  struct lock_class *class)
 {
 	struct lock_chain *chain;
-	struct hlist_head *head;
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(chainhash_table); i++) {
-		head = chainhash_table + i;
-		hlist_for_each_entry_rcu(chain, head, entry) {
-			remove_class_from_lock_chain(pf, chain, class);
-		}
+	hash_for_each_rcu(chainhash_table, i, chain, entry) {
+		remove_class_from_lock_chain(pf, chain, class);
 	}
 }
 
@@ -6370,18 +6357,14 @@ static void __lockdep_free_key_range(struct pending_free *pf, void *start,
 				     unsigned long size)
 {
 	struct lock_class *class;
-	struct hlist_head *head;
 	int i;
 
 	/* Unhash all classes that were created by a module. */
-	for (i = 0; i < CLASSHASH_SIZE; i++) {
-		head = classhash_table + i;
-		hlist_for_each_entry_rcu(class, head, hash_entry) {
-			if (!within(class->key, start, size) &&
-			    !within(class->name, start, size))
-				continue;
-			zap_class(pf, class);
-		}
+	hash_for_each_rcu(classhash_table, i, class, hash_entry) {
+		if (!within(class->key, start, size) &&
+		    !within(class->name, start, size))
+			continue;
+		zap_class(pf, class);
 	}
 }
 
@@ -6454,16 +6437,12 @@ void lockdep_free_key_range(void *start, unsigned long size)
 static bool lock_class_cache_is_registered(struct lockdep_map *lock)
 {
 	struct lock_class *class;
-	struct hlist_head *head;
 	int i, j;
 
-	for (i = 0; i < CLASSHASH_SIZE; i++) {
-		head = classhash_table + i;
-		hlist_for_each_entry_rcu(class, head, hash_entry) {
-			for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
-				if (lock->class_cache[j] == class)
-					return true;
-		}
+	hash_for_each_rcu(classhash_table, i, class, hash_entry) {
+		for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
+			if (lock->class_cache[j] == class)
+				return true;
 	}
 	return false;
 }
@@ -6605,7 +6584,7 @@ void __init lockdep_init(void)
 	pr_info("... MAX_LOCKDEP_SUBCLASSES:  %lu\n", MAX_LOCKDEP_SUBCLASSES);
 	pr_info("... MAX_LOCK_DEPTH:          %lu\n", MAX_LOCK_DEPTH);
 	pr_info("... MAX_LOCKDEP_KEYS:        %lu\n", MAX_LOCKDEP_KEYS);
-	pr_info("... CLASSHASH_SIZE:          %lu\n", CLASSHASH_SIZE);
+	pr_info("... CLASSHASH_SIZE:          %lu\n", HASH_SIZE(classhash_table));
 	pr_info("... MAX_LOCKDEP_ENTRIES:     %lu\n", MAX_LOCKDEP_ENTRIES);
 	pr_info("... MAX_LOCKDEP_CHAINS:      %lu\n", MAX_LOCKDEP_CHAINS);
 	pr_info("... CHAINHASH_SIZE:          %lu\n", CHAINHASH_SIZE);
-- 
2.39.5

[PATCH 3/4] locking/lockdep: Use hashtable.h for chainhash_table

[Sasha Levin]

Convert chainhash_table in lockdep.c to use the generic hashtable
implementation from hashtable.h instead of the manual hlist_head array
implementation.

This simplifies the code and makes it more maintainable by using the
standard hashtable API and removes the need for custom hash lookup
functions.

Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/locking/lockdep.c | 26 +++++++++-----------------
 1 file changed, 9 insertions(+), 17 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index b071bbf0d955c..151fec00f1c2c 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -412,11 +412,7 @@ static DEFINE_HASHTABLE(classhash_table, CLASSHASH_BITS);
  * their existence:
  */
 #define CHAINHASH_BITS		(MAX_LOCKDEP_CHAINS_BITS-1)
-#define CHAINHASH_SIZE		(1UL << CHAINHASH_BITS)
-#define __chainhashfn(chain)	hash_long(chain, CHAINHASH_BITS)
-#define chainhashentry(chain)	(chainhash_table + __chainhashfn((chain)))
-
-static struct hlist_head chainhash_table[CHAINHASH_SIZE];
+DEFINE_HASHTABLE(chainhash_table, CHAINHASH_BITS);
 
 /*
  * the id of held_lock
@@ -3716,7 +3712,6 @@ static inline int add_chain_cache(struct task_struct *curr,
 				  struct held_lock *hlock,
 				  u64 chain_key)
 {
-	struct hlist_head *hash_head = chainhashentry(chain_key);
 	struct lock_chain *chain;
 	int i, j;
 
@@ -3767,7 +3762,7 @@ static inline int add_chain_cache(struct task_struct *curr,
 		chain_hlocks[chain->base + j] = lock_id;
 	}
 	chain_hlocks[chain->base + j] = hlock_id(hlock);
-	hlist_add_head_rcu(&chain->entry, hash_head);
+	hash_add_rcu(chainhash_table, &chain->entry, chain_key);
 	debug_atomic_inc(chain_lookup_misses);
 	inc_chains(chain->irq_context);
 
@@ -3780,10 +3775,9 @@ static inline int add_chain_cache(struct task_struct *curr,
  */
 static inline struct lock_chain *lookup_chain_cache(u64 chain_key)
 {
-	struct hlist_head *hash_head = chainhashentry(chain_key);
 	struct lock_chain *chain;
 
-	hlist_for_each_entry_rcu(chain, hash_head, entry) {
+	hash_for_each_possible_rcu(chainhash_table, chain, entry, chain_key) {
 		if (READ_ONCE(chain->chain_key) == chain_key) {
 			debug_atomic_inc(chain_lookup_hits);
 			return chain;
@@ -6142,7 +6136,6 @@ EXPORT_SYMBOL_GPL(lock_acquired);
 void lockdep_reset(void)
 {
 	unsigned long flags;
-	int i;
 
 	raw_local_irq_save(flags);
 	lockdep_init_task(current);
@@ -6151,8 +6144,7 @@ void lockdep_reset(void)
 	nr_softirq_chains = 0;
 	nr_process_chains = 0;
 	debug_locks = 1;
-	for (i = 0; i < CHAINHASH_SIZE; i++)
-		INIT_HLIST_HEAD(chainhash_table + i);
+	hash_init(chainhash_table);
 	raw_local_irq_restore(flags);
 }
 
@@ -6183,10 +6175,10 @@ static void remove_class_from_lock_chain(struct pending_free *pf,
 	dec_chains(chain->irq_context);
 
 	/*
-	 * Note: calling hlist_del_rcu() from inside a
-	 * hlist_for_each_entry_rcu() loop is safe.
+	 * Note: calling hash_del_rcu() from inside a
+	 * hash_for_each_rcu() loop is safe.
 	 */
-	hlist_del_rcu(&chain->entry);
+	hash_del_rcu(&chain->entry);
 	__set_bit(chain - lock_chains, pf->lock_chains_being_freed);
 	nr_zapped_lock_chains++;
 #endif
@@ -6229,7 +6221,7 @@ static void zap_class(struct pending_free *pf, struct lock_class *class)
 	if (list_empty(&class->locks_after) &&
 	    list_empty(&class->locks_before)) {
 		list_move_tail(&class->lock_entry, &pf->zapped);
-		hlist_del_rcu(&class->hash_entry);
+		hash_del_rcu(&class->hash_entry);
 		WRITE_ONCE(class->key, NULL);
 		WRITE_ONCE(class->name, NULL);
 		nr_lock_classes--;
@@ -6587,7 +6579,7 @@ void __init lockdep_init(void)
 	pr_info("... CLASSHASH_SIZE:          %lu\n", HASH_SIZE(classhash_table));
 	pr_info("... MAX_LOCKDEP_ENTRIES:     %lu\n", MAX_LOCKDEP_ENTRIES);
 	pr_info("... MAX_LOCKDEP_CHAINS:      %lu\n", MAX_LOCKDEP_CHAINS);
-	pr_info("... CHAINHASH_SIZE:          %lu\n", CHAINHASH_SIZE);
+	pr_info("... CHAINHASH_SIZE:          %lu\n", HASH_SIZE(chainhash_table));
 
 	pr_info(" memory used by lock dependency info: %zu kB\n",
 	       (sizeof(lock_classes) +
-- 
2.39.5

[PATCH 4/4] locking/lockdep: Use hashtable.h for stack_trace_hash

[Sasha Levin]

Convert stack_trace_hash in lockdep.c to use the generic hashtable
implementation from hashtable.h instead of the manual hlist_head array
implementation.

This simplifies the code and makes it more maintainable by using the
standard hashtable API and removes the need for custom hash lookup
functions.

Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/locking/lockdep.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 151fec00f1c2c..987b81f2ddb77 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -541,7 +541,8 @@ struct lock_trace {
  * Stack-trace: sequence of lock_trace structures. Protected by the graph_lock.
  */
 static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
-static struct hlist_head stack_trace_hash[STACK_TRACE_HASH_SIZE];
+#define STACK_TRACE_HASH_BITS (ilog2(STACK_TRACE_HASH_SIZE))
+static DEFINE_HASHTABLE(stack_trace_hash, STACK_TRACE_HASH_BITS);
 
 static bool traces_identical(struct lock_trace *t1, struct lock_trace *t2)
 {
@@ -553,7 +554,6 @@ static bool traces_identical(struct lock_trace *t1, struct lock_trace *t2)
 static struct lock_trace *save_trace(void)
 {
 	struct lock_trace *trace, *t2;
-	struct hlist_head *hash_head;
 	u32 hash;
 	int max_entries;
 
@@ -580,13 +580,13 @@ static struct lock_trace *save_trace(void)
 	hash = jhash(trace->entries, trace->nr_entries *
 		     sizeof(trace->entries[0]), 0);
 	trace->hash = hash;
-	hash_head = stack_trace_hash + (hash & (STACK_TRACE_HASH_SIZE - 1));
-	hlist_for_each_entry(t2, hash_head, hash_entry) {
+
+	hash_for_each_possible(stack_trace_hash, t2, hash_entry, hash)
 		if (traces_identical(trace, t2))
 			return t2;
-	}
+
 	nr_stack_trace_entries += LOCK_TRACE_SIZE_IN_LONGS + trace->nr_entries;
-	hlist_add_head(&trace->hash_entry, hash_head);
+	hash_add(stack_trace_hash, &trace->hash_entry, hash);
 
 	return trace;
 }
@@ -598,11 +598,8 @@ u64 lockdep_stack_trace_count(void)
 	u64 c = 0;
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(stack_trace_hash); i++) {
-		hlist_for_each_entry(trace, &stack_trace_hash[i], hash_entry) {
-			c++;
-		}
-	}
+	hash_for_each(stack_trace_hash, i, trace, hash_entry)
+		c++;
 
 	return c;
 }
@@ -613,7 +610,7 @@ u64 lockdep_stack_hash_count(void)
 	u64 c = 0;
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(stack_trace_hash); i++)
+	for (i = 0; i < HASH_SIZE(stack_trace_hash); i++)
 		if (!hlist_empty(&stack_trace_hash[i]))
 			c++;
 
-- 
2.39.5

Re: [PATCH 1/4] locking/lockdep: Use hashtable.h for lock_keys_hash

[Boqun Feng]

Hi Sasha,

Thanks for the patches. I want to let you know that we are currently
doing some changes on the hashlist usage in lockdep:

	https://lore.kernel.org/lkml/20250414060055.341516-1-boqun.feng@gmail.com/	

so, it may take a while for me to back looking into this (until that get
sorted).

Regards,
Boqun

On Thu, Mar 20, 2025 at 10:31:17AM -0400, Sasha Levin wrote:
> Convert the lock_keys_hash array in lockdep.c to use the generic
> hashtable implementation from hashtable.h instead of the manual
> hlist_head array implementation.
> 
> This simplifies the code and makes it more maintainable by using the
> standard hashtable API defined in hashtable.h, while preserving the
> RCU-safe behavior with proper RCU variants of the hashtable functions.
> 
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  kernel/locking/lockdep.c | 34 ++++++++++++++++------------------
>  1 file changed, 16 insertions(+), 18 deletions(-)
> 
> diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> index 4470680f02269..160cf8310eda0 100644
> --- a/kernel/locking/lockdep.c
> +++ b/kernel/locking/lockdep.c
> @@ -57,6 +57,7 @@
>  #include <linux/lockdep.h>
>  #include <linux/context_tracking.h>
>  #include <linux/console.h>
> +#include <linux/hashtable.h>
>  
>  #include <asm/sections.h>
>  
> @@ -212,8 +213,7 @@ static DECLARE_BITMAP(list_entries_in_use, MAX_LOCKDEP_ENTRIES);
>   * in use.
>   */
>  #define KEYHASH_BITS		(MAX_LOCKDEP_KEYS_BITS - 1)
> -#define KEYHASH_SIZE		(1UL << KEYHASH_BITS)
> -static struct hlist_head lock_keys_hash[KEYHASH_SIZE];
> +static DEFINE_HASHTABLE(lock_keys_hash, KEYHASH_BITS);
>  unsigned long nr_lock_classes;
>  unsigned long nr_zapped_classes;
>  unsigned long max_lock_class_idx;
> @@ -1209,32 +1209,28 @@ static void init_data_structures_once(void)
>  	init_chain_block_buckets();
>  }
>  
> -static inline struct hlist_head *keyhashentry(const struct lock_class_key *key)
> -{
> -	unsigned long hash = hash_long((uintptr_t)key, KEYHASH_BITS);
> -
> -	return lock_keys_hash + hash;
> -}
>  
>  /* Register a dynamically allocated key. */
>  void lockdep_register_key(struct lock_class_key *key)
>  {
> -	struct hlist_head *hash_head;
>  	struct lock_class_key *k;
> +	unsigned long hash;
>  	unsigned long flags;
>  
>  	if (WARN_ON_ONCE(static_obj(key)))
>  		return;
> -	hash_head = keyhashentry(key);
> +
> +	hash = hash_long((uintptr_t)key, KEYHASH_BITS);
>  
>  	raw_local_irq_save(flags);
>  	if (!graph_lock())
>  		goto restore_irqs;
> -	hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
> +
> +	hash_for_each_possible_rcu(lock_keys_hash, k, hash_entry, hash) {
>  		if (WARN_ON_ONCE(k == key))
>  			goto out_unlock;
>  	}
> -	hlist_add_head_rcu(&key->hash_entry, hash_head);
> +	hash_add_rcu(lock_keys_hash, &key->hash_entry, hash);
>  out_unlock:
>  	graph_unlock();
>  restore_irqs:
> @@ -1245,8 +1241,8 @@ EXPORT_SYMBOL_GPL(lockdep_register_key);
>  /* Check whether a key has been registered as a dynamic key. */
>  static bool is_dynamic_key(const struct lock_class_key *key)
>  {
> -	struct hlist_head *hash_head;
>  	struct lock_class_key *k;
> +	unsigned long hash;
>  	bool found = false;
>  
>  	if (WARN_ON_ONCE(static_obj(key)))
> @@ -1260,10 +1256,10 @@ static bool is_dynamic_key(const struct lock_class_key *key)
>  	if (!debug_locks)
>  		return true;
>  
> -	hash_head = keyhashentry(key);
> +	hash = hash_long((uintptr_t)key, KEYHASH_BITS);
>  
>  	rcu_read_lock();
> -	hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
> +	hash_for_each_possible_rcu(lock_keys_hash, k, hash_entry, hash) {
>  		if (k == key) {
>  			found = true;
>  			break;
> @@ -6561,9 +6557,9 @@ void lockdep_reset_lock(struct lockdep_map *lock)
>   */
>  void lockdep_unregister_key(struct lock_class_key *key)
>  {
> -	struct hlist_head *hash_head = keyhashentry(key);
>  	struct lock_class_key *k;
>  	struct pending_free *pf;
> +	unsigned long hash;
>  	unsigned long flags;
>  	bool found = false;
>  	bool need_callback = false;
> @@ -6573,12 +6569,14 @@ void lockdep_unregister_key(struct lock_class_key *key)
>  	if (WARN_ON_ONCE(static_obj(key)))
>  		return;
>  
> +	hash = hash_long((uintptr_t)key, KEYHASH_BITS);
> +
>  	raw_local_irq_save(flags);
>  	lockdep_lock();
>  
> -	hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
> +	hash_for_each_possible(lock_keys_hash, k, hash_entry, hash) {
>  		if (k == key) {
> -			hlist_del_rcu(&k->hash_entry);
> +			hash_del_rcu(&k->hash_entry);
>  			found = true;
>  			break;
>  		}
> -- 
> 2.39.5
>