1 files changed, 237 insertions, 83 deletions

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 5d845ffd7982..32d0ad058380 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -30,7 +30,7 @@
 
 #define HASH_DEFAULT_SIZE	64UL
 #define HASH_MIN_SIZE		4U
-#define BUCKET_LOCKS_PER_CPU   128UL
+#define BUCKET_LOCKS_PER_CPU	32UL
 
 static u32 head_hashfn(struct rhashtable *ht,
 		       const struct bucket_table *tbl,
@@ -70,21 +70,25 @@ static int alloc_bucket_locks(struct rhashtable *ht, struct bucket_table *tbl,
 	unsigned int nr_pcpus = num_possible_cpus();
 #endif
 
-	nr_pcpus = min_t(unsigned int, nr_pcpus, 32UL);
+	nr_pcpus = min_t(unsigned int, nr_pcpus, 64UL);
 	size = roundup_pow_of_two(nr_pcpus * ht->p.locks_mul);
 
 	/* Never allocate more than 0.5 locks per bucket */
 	size = min_t(unsigned int, size, tbl->size >> 1);
 
 	if (sizeof(spinlock_t) != 0) {
+		tbl->locks = NULL;
 #ifdef CONFIG_NUMA
 		if (size * sizeof(spinlock_t) > PAGE_SIZE &&
 		    gfp == GFP_KERNEL)
 			tbl->locks = vmalloc(size * sizeof(spinlock_t));
-		else
 #endif
-		tbl->locks = kmalloc_array(size, sizeof(spinlock_t),
-					   gfp);
+		if (gfp != GFP_KERNEL)
+			gfp |= __GFP_NOWARN | __GFP_NORETRY;
+
+		if (!tbl->locks)
+			tbl->locks = kmalloc_array(size, sizeof(spinlock_t),
+						   gfp);
 		if (!tbl->locks)
 			return -ENOMEM;
 		for (i = 0; i < size; i++)
@@ -321,12 +325,14 @@ static int rhashtable_expand(struct rhashtable *ht)
 static int rhashtable_shrink(struct rhashtable *ht)
 {
 	struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht);
-	unsigned int size;
+	unsigned int nelems = atomic_read(&ht->nelems);
+	unsigned int size = 0;
 	int err;
 
 	ASSERT_RHT_MUTEX(ht);
 
-	size = roundup_pow_of_two(atomic_read(&ht->nelems) * 3 / 2);
+	if (nelems)
+		size = roundup_pow_of_two(nelems * 3 / 2);
 	if (size < ht->p.min_size)
 		size = ht->p.min_size;
 
@@ -372,22 +378,8 @@ static void rht_deferred_worker(struct work_struct *work)
 		schedule_work(&ht->run_work);
 }
 
-static bool rhashtable_check_elasticity(struct rhashtable *ht,
-					struct bucket_table *tbl,
-					unsigned int hash)
-{
-	unsigned int elasticity = ht->elasticity;
-	struct rhash_head *head;
-
-	rht_for_each(head, tbl, hash)
-		if (!--elasticity)
-			return true;
-
-	return false;
-}
-
-int rhashtable_insert_rehash(struct rhashtable *ht,
-			     struct bucket_table *tbl)
+static int rhashtable_insert_rehash(struct rhashtable *ht,
+				    struct bucket_table *tbl)
 {
 	struct bucket_table *old_tbl;
 	struct bucket_table *new_tbl;
@@ -433,61 +425,172 @@ fail:
 
 	return err;
 }
-EXPORT_SYMBOL_GPL(rhashtable_insert_rehash);
 
-struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
-					    const void *key,
-					    struct rhash_head *obj,
-					    struct bucket_table *tbl)
+static void *rhashtable_lookup_one(struct rhashtable *ht,
+				   struct bucket_table *tbl, unsigned int hash,
+				   const void *key, struct rhash_head *obj)
 {
+	struct rhashtable_compare_arg arg = {
+		.ht = ht,
+		.key = key,
+	};
+	struct rhash_head __rcu **pprev;
 	struct rhash_head *head;
-	unsigned int hash;
-	int err;
+	int elasticity;
 
-	tbl = rhashtable_last_table(ht, tbl);
-	hash = head_hashfn(ht, tbl, obj);
-	spin_lock_nested(rht_bucket_lock(tbl, hash), SINGLE_DEPTH_NESTING);
+	elasticity = ht->elasticity;
+	pprev = &tbl->buckets[hash];
+	rht_for_each(head, tbl, hash) {
+		struct rhlist_head *list;
+		struct rhlist_head *plist;
 
-	err = -EEXIST;
-	if (key && rhashtable_lookup_fast(ht, key, ht->p))
-		goto exit;
+		elasticity--;
+		if (!key ||
+		    (ht->p.obj_cmpfn ?
+		     ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) :
+		     rhashtable_compare(&arg, rht_obj(ht, head))))
+			continue;
 
-	err = -E2BIG;
-	if (unlikely(rht_grow_above_max(ht, tbl)))
-		goto exit;
+		if (!ht->rhlist)
+			return rht_obj(ht, head);
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		plist = container_of(head, struct rhlist_head, rhead);
+
+		RCU_INIT_POINTER(list->next, plist);
+		head = rht_dereference_bucket(head->next, tbl, hash);
+		RCU_INIT_POINTER(list->rhead.next, head);
+		rcu_assign_pointer(*pprev, obj);
 
-	err = -EAGAIN;
-	if (rhashtable_check_elasticity(ht, tbl, hash) ||
-	    rht_grow_above_100(ht, tbl))
-		goto exit;
+		return NULL;
+	}
 
-	err = 0;
+	if (elasticity <= 0)
+		return ERR_PTR(-EAGAIN);
+
+	return ERR_PTR(-ENOENT);
+}
+
+static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht,
+						  struct bucket_table *tbl,
+						  unsigned int hash,
+						  struct rhash_head *obj,
+						  void *data)
+{
+	struct bucket_table *new_tbl;
+	struct rhash_head *head;
+
+	if (!IS_ERR_OR_NULL(data))
+		return ERR_PTR(-EEXIST);
+
+	if (PTR_ERR(data) != -EAGAIN && PTR_ERR(data) != -ENOENT)
+		return ERR_CAST(data);
+
+	new_tbl = rcu_dereference(tbl->future_tbl);
+	if (new_tbl)
+		return new_tbl;
+
+	if (PTR_ERR(data) != -ENOENT)
+		return ERR_CAST(data);
+
+	if (unlikely(rht_grow_above_max(ht, tbl)))
+		return ERR_PTR(-E2BIG);
+
+	if (unlikely(rht_grow_above_100(ht, tbl)))
+		return ERR_PTR(-EAGAIN);
 
 	head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
 	RCU_INIT_POINTER(obj->next, head);
+	if (ht->rhlist) {
+		struct rhlist_head *list;
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		RCU_INIT_POINTER(list->next, NULL);
+	}
 
 	rcu_assign_pointer(tbl->buckets[hash], obj);
 
 	atomic_inc(&ht->nelems);
+	if (rht_grow_above_75(ht, tbl))
+		schedule_work(&ht->run_work);
 
-exit:
-	spin_unlock(rht_bucket_lock(tbl, hash));
+	return NULL;
+}
 
-	if (err == 0)
-		return NULL;
-	else if (err == -EAGAIN)
-		return tbl;
-	else
-		return ERR_PTR(err);
+static void *rhashtable_try_insert(struct rhashtable *ht, const void *key,
+				   struct rhash_head *obj)
+{
+	struct bucket_table *new_tbl;
+	struct bucket_table *tbl;
+	unsigned int hash;
+	spinlock_t *lock;
+	void *data;
+
+	tbl = rcu_dereference(ht->tbl);
+
+	/* All insertions must grab the oldest table containing
+	 * the hashed bucket that is yet to be rehashed.
+	 */
+	for (;;) {
+		hash = rht_head_hashfn(ht, tbl, obj, ht->p);
+		lock = rht_bucket_lock(tbl, hash);
+		spin_lock_bh(lock);
+
+		if (tbl->rehash <= hash)
+			break;
+
+		spin_unlock_bh(lock);
+		tbl = rcu_dereference(tbl->future_tbl);
+	}
+
+	data = rhashtable_lookup_one(ht, tbl, hash, key, obj);
+	new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data);
+	if (PTR_ERR(new_tbl) != -EEXIST)
+		data = ERR_CAST(new_tbl);
+
+	while (!IS_ERR_OR_NULL(new_tbl)) {
+		tbl = new_tbl;
+		hash = rht_head_hashfn(ht, tbl, obj, ht->p);
+		spin_lock_nested(rht_bucket_lock(tbl, hash),
+				 SINGLE_DEPTH_NESTING);
+
+		data = rhashtable_lookup_one(ht, tbl, hash, key, obj);
+		new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data);
+		if (PTR_ERR(new_tbl) != -EEXIST)
+			data = ERR_CAST(new_tbl);
+
+		spin_unlock(rht_bucket_lock(tbl, hash));
+	}
+
+	spin_unlock_bh(lock);
+
+	if (PTR_ERR(data) == -EAGAIN)
+		data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?:
+			       -EAGAIN);
+
+	return data;
+}
+
+void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
+			     struct rhash_head *obj)
+{
+	void *data;
+
+	do {
+		rcu_read_lock();
+		data = rhashtable_try_insert(ht, key, obj);
+		rcu_read_unlock();
+	} while (PTR_ERR(data) == -EAGAIN);
+
+	return data;
 }
 EXPORT_SYMBOL_GPL(rhashtable_insert_slow);
 
 /**
- * rhashtable_walk_init - Initialise an iterator
+ * rhashtable_walk_enter - Initialise an iterator
  * @ht:		Table to walk over
  * @iter:	Hash table Iterator
- * @gfp:	GFP flags for allocations
  *
  * This function prepares a hash table walk.
  *
@@ -502,30 +605,22 @@ EXPORT_SYMBOL_GPL(rhashtable_insert_slow);
  * This function may sleep so you must not call it from interrupt
  * context or with spin locks held.
  *
- * You must call rhashtable_walk_exit if this function returns
- * successfully.
+ * You must call rhashtable_walk_exit after this function returns.
  */
-int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter,
-			 gfp_t gfp)
+void rhashtable_walk_enter(struct rhashtable *ht, struct rhashtable_iter *iter)
 {
 	iter->ht = ht;
 	iter->p = NULL;
 	iter->slot = 0;
 	iter->skip = 0;
 
-	iter->walker = kmalloc(sizeof(*iter->walker), gfp);
-	if (!iter->walker)
-		return -ENOMEM;
-
 	spin_lock(&ht->lock);
-	iter->walker->tbl =
+	iter->walker.tbl =
 		rcu_dereference_protected(ht->tbl, lockdep_is_held(&ht->lock));
-	list_add(&iter->walker->list, &iter->walker->tbl->walkers);
+	list_add(&iter->walker.list, &iter->walker.tbl->walkers);
 	spin_unlock(&ht->lock);
-
-	return 0;
 }
-EXPORT_SYMBOL_GPL(rhashtable_walk_init);
+EXPORT_SYMBOL_GPL(rhashtable_walk_enter);
 
 /**
  * rhashtable_walk_exit - Free an iterator
@@ -536,10 +631,9 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_init);
 void rhashtable_walk_exit(struct rhashtable_iter *iter)
 {
 	spin_lock(&iter->ht->lock);
-	if (iter->walker->tbl)
-		list_del(&iter->walker->list);
+	if (iter->walker.tbl)
+		list_del(&iter->walker.list);
 	spin_unlock(&iter->ht->lock);
-	kfree(iter->walker);
 }
 EXPORT_SYMBOL_GPL(rhashtable_walk_exit);
 
@@ -565,12 +659,12 @@ int rhashtable_walk_start(struct rhashtable_iter *iter)
 	rcu_read_lock();
 
 	spin_lock(&ht->lock);
-	if (iter->walker->tbl)
-		list_del(&iter->walker->list);
+	if (iter->walker.tbl)
+		list_del(&iter->walker.list);
 	spin_unlock(&ht->lock);
 
-	if (!iter->walker->tbl) {
-		iter->walker->tbl = rht_dereference_rcu(ht->tbl, ht);
+	if (!iter->walker.tbl) {
+		iter->walker.tbl = rht_dereference_rcu(ht->tbl, ht);
 		return -EAGAIN;
 	}
 
@@ -592,12 +686,17 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_start);
  */
 void *rhashtable_walk_next(struct rhashtable_iter *iter)
 {
-	struct bucket_table *tbl = iter->walker->tbl;
+	struct bucket_table *tbl = iter->walker.tbl;
+	struct rhlist_head *list = iter->list;
 	struct rhashtable *ht = iter->ht;
 	struct rhash_head *p = iter->p;
+	bool rhlist = ht->rhlist;
 
 	if (p) {
-		p = rht_dereference_bucket_rcu(p->next, tbl, iter->slot);
+		if (!rhlist || !(list = rcu_dereference(list->next))) {
+			p = rcu_dereference(p->next);
+			list = container_of(p, struct rhlist_head, rhead);
+		}
 		goto next;
 	}
 
@@ -605,6 +704,18 @@ void *rhashtable_walk_next(struct rhashtable_iter *iter)
 		int skip = iter->skip;
 
 		rht_for_each_rcu(p, tbl, iter->slot) {
+			if (rhlist) {
+				list = container_of(p, struct rhlist_head,
+						    rhead);
+				do {
+					if (!skip)
+						goto next;
+					skip--;
+					list = rcu_dereference(list->next);
+				} while (list);
+
+				continue;
+			}
 			if (!skip)
 				break;
 			skip--;
@@ -614,7 +725,8 @@ next:
 		if (!rht_is_a_nulls(p)) {
 			iter->skip++;
 			iter->p = p;
-			return rht_obj(ht, p);
+			iter->list = list;
+			return rht_obj(ht, rhlist ? &list->rhead : p);
 		}
 
 		iter->skip = 0;
@@ -625,8 +737,8 @@ next:
 	/* Ensure we see any new tables. */
 	smp_rmb();
 
-	iter->walker->tbl = rht_dereference_rcu(tbl->future_tbl, ht);
-	if (iter->walker->tbl) {
+	iter->walker.tbl = rht_dereference_rcu(tbl->future_tbl, ht);
+	if (iter->walker.tbl) {
 		iter->slot = 0;
 		iter->skip = 0;
 		return ERR_PTR(-EAGAIN);
@@ -646,7 +758,7 @@ void rhashtable_walk_stop(struct rhashtable_iter *iter)
 	__releases(RCU)
 {
 	struct rhashtable *ht;
-	struct bucket_table *tbl = iter->walker->tbl;
+	struct bucket_table *tbl = iter->walker.tbl;
 
 	if (!tbl)
 		goto out;
@@ -655,9 +767,9 @@ void rhashtable_walk_stop(struct rhashtable_iter *iter)
 
 	spin_lock(&ht->lock);
 	if (tbl->rehash < tbl->size)
-		list_add(&iter->walker->list, &tbl->walkers);
+		list_add(&iter->walker.list, &tbl->walkers);
 	else
-		iter->walker->tbl = NULL;
+		iter->walker.tbl = NULL;
 	spin_unlock(&ht->lock);
 
 	iter->p = NULL;
@@ -803,6 +915,48 @@ int rhashtable_init(struct rhashtable *ht,
 EXPORT_SYMBOL_GPL(rhashtable_init);
 
 /**
+ * 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(struct rhltable *hlt, const struct rhashtable_params *params)
+{
+	int err;
+
+	/* No rhlist NULLs marking for now. */
+	if (params->nulls_base)
+		return -EINVAL;
+
+	err = rhashtable_init(&hlt->ht, params);
+	hlt->ht.rhlist = true;
+	return err;
+}
+EXPORT_SYMBOL_GPL(rhltable_init);
+
+static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj,
+				void (*free_fn)(void *ptr, void *arg),
+				void *arg)
+{
+	struct rhlist_head *list;
+
+	if (!ht->rhlist) {
+		free_fn(rht_obj(ht, obj), arg);
+		return;
+	}
+
+	list = container_of(obj, struct rhlist_head, rhead);
+	do {
+		obj = &list->rhead;
+		list = rht_dereference(list->next, ht);
+		free_fn(rht_obj(ht, obj), arg);
+	} while (list);
+}
+
+/**
  * rhashtable_free_and_destroy - free elements and destroy hash table
  * @ht:		the hash table to destroy
  * @free_fn:	callback to release resources of element
@@ -839,7 +993,7 @@ void rhashtable_free_and_destroy(struct rhashtable *ht,
 			     pos = next,
 			     next = !rht_is_a_nulls(pos) ?
 					rht_dereference(pos->next, ht) : NULL)
-				free_fn(rht_obj(ht, pos), arg);
+				rhashtable_free_one(ht, pos, free_fn, arg);
 		}
 	}