rhashtable: Use separate lockdep keys for each lock

Use separate lockdep keys for the different types of locks in
rhashtable (mutex, spin lock, and bucket locks).  They are
separate and not normally nested with respect to each other.

Also move the rhashtable_init/rhltable_init kdoc to the header
file as that's where the macros are defined.

Fixes: 4333ab90aaae ("rhashtable: use private lockdep class for all locks.")
Reported-by: syzbot+4d0e4d2db6dfde01b52f@syzkaller.appspotmail.com
Assisted-by: Gemini:gemini-3.6-flash
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: NeilBrown <neil@brown.name>
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

2 files changed, 9 insertions, 63 deletions

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 5da0e53a8d42..a3a4a1f7751e 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -207,7 +207,6 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
 		return NULL;
 
 #ifdef CONFIG_LOCKDEP
-	/* bitlocks must use nesting level 2 or more */
 	lockdep_init_map(&tbl->dep_map, "rhashtable_bucket", ht->lockdep_key, 0);
 #endif
 
@@ -432,7 +431,7 @@ static void rht_deferred_worker(struct work_struct *work)
 	int err = 0;
 
 	ht = container_of(work, struct rhashtable, run_work);
-	mutex_lock_nested(&ht->mutex, 1);
+	mutex_lock(&ht->mutex);
 
 	tbl = rht_dereference(ht->tbl, ht);
 	tbl = rhashtable_last_table(ht, tbl);
@@ -1122,51 +1121,9 @@ static u32 rhashtable_jhash2(const void *key, u32 length, u32 seed)
 	return jhash2(key, length, seed);
 }
 
-/**
- * rhashtable_init - initialize a new hash table
- * @ht:		hash table to be initialized
- * @params:	configuration parameters
- *
- * Initializes a new hash table based on the provided configuration
- * parameters. A table can be configured either with a variable or
- * fixed length key:
- *
- * Configuration Example 1: Fixed length keys
- * struct test_obj {
- *	int			key;
- *	void *			my_member;
- *	struct rhash_head	node;
- * };
- *
- * struct rhashtable_params params = {
- *	.head_offset = offsetof(struct test_obj, node),
- *	.key_offset = offsetof(struct test_obj, key),
- *	.key_len = sizeof(int),
- *	.hashfn = jhash,
- * };
- *
- * Configuration Example 2: Variable length keys
- * struct test_obj {
- *	[...]
- *	struct rhash_head	node;
- * };
- *
- * u32 my_hash_fn(const void *data, u32 len, u32 seed)
- * {
- *	struct test_obj *obj = data;
- *
- *	return [... hash ...];
- * }
- *
- * struct rhashtable_params params = {
- *	.head_offset = offsetof(struct test_obj, node),
- *	.hashfn = jhash,
- *	.obj_hashfn = my_hash_fn,
- * };
- */
 int __rhashtable_init_noprof(struct rhashtable *ht,
-		    const struct rhashtable_params *params,
-		    struct lock_class_key *key)
+			     const struct rhashtable_params *params,
+			     struct rhashtable_lockdep_keys *keys)
 {
 	struct bucket_table *tbl;
 	size_t size;
@@ -1176,13 +1133,11 @@ int __rhashtable_init_noprof(struct rhashtable *ht,
 		return -EINVAL;
 
 	memset(ht, 0, sizeof(*ht));
-	/* mutex_lock must use nesting level 1 */
-	mutex_init_with_key(&ht->mutex, key);
+	mutex_init_with_key(&ht->mutex, &keys->mutex_key);
 	spin_lock_init(&ht->lock);
-	/* spin_lock can use nesting level 0 */
-	lockdep_set_class(&ht->lock, key);
+	lockdep_set_class(&ht->lock, &keys->lock_key);
 #ifdef CONFIG_LOCKDEP
-	ht->lockdep_key = key;
+	ht->lockdep_key = &keys->bucket_key;
 #endif
 	memcpy(&ht->p, params, sizeof(*params));
 
@@ -1236,22 +1191,13 @@ int __rhashtable_init_noprof(struct rhashtable *ht,
 }
 EXPORT_SYMBOL_GPL(__rhashtable_init_noprof);
 
-/**
- * rhltable_init - initialize a new hash list table
- * @hlt:	hash list table to be initialized
- * @params:	configuration parameters
- *
- * Initializes a new hash list table.
- *
- * See documentation for rhashtable_init.
- */
 int __rhltable_init_noprof(struct rhltable *hlt,
 			   const struct rhashtable_params *params,
-			   struct lock_class_key *key)
+			   struct rhashtable_lockdep_keys *keys)
 {
 	int err;
 
-	err = __rhashtable_init_noprof(&hlt->ht, params, key);
+	err = __rhashtable_init_noprof(&hlt->ht, params, keys);
 	hlt->ht.rhlist = true;
 	return err;
 }
diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c
index 85a615e74591..b767a38a74f9 100644
--- a/lib/test_rhashtable.c
+++ b/lib/test_rhashtable.c
@@ -477,7 +477,7 @@ static unsigned int __init print_ht(struct rhltable *rhlt)
 
 	ht = &rhlt->ht;
 	/* Take the mutex to avoid RCU warning */
-	mutex_lock_nested(&ht->mutex, 1);
+	mutex_lock(&ht->mutex);
 	tbl = rht_dereference(ht->tbl, ht);
 	for (i = 0; i < tbl->size; i++) {
 		struct rhash_head *pos, *next;