bpf: Split bpf_local_storage to bpf_sk_storage

A purely mechanical change:

	bpf_sk_storage.c = bpf_sk_storage.c + bpf_local_storage.c
	bpf_sk_storage.h = bpf_sk_storage.h + bpf_local_storage.h

Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200825182919.1118197-5-kpsingh@chromium.org

5 files changed, 766 insertions, 731 deletions

diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h
new file mode 100644
index 000000000000..b2c9463f36a1
--- /dev/null
+++ b/include/linux/bpf_local_storage.h
@@ -0,0 +1,163 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2019 Facebook
+ * Copyright 2020 Google LLC.
+ */
+
+#ifndef _BPF_LOCAL_STORAGE_H
+#define _BPF_LOCAL_STORAGE_H
+
+#include <linux/bpf.h>
+#include <linux/rculist.h>
+#include <linux/list.h>
+#include <linux/hash.h>
+#include <linux/types.h>
+#include <uapi/linux/btf.h>
+
+#define BPF_LOCAL_STORAGE_CACHE_SIZE	16
+
+struct bpf_local_storage_map_bucket {
+	struct hlist_head list;
+	raw_spinlock_t lock;
+};
+
+/* Thp map is not the primary owner of a bpf_local_storage_elem.
+ * Instead, the container object (eg. sk->sk_bpf_storage) is.
+ *
+ * The map (bpf_local_storage_map) is for two purposes
+ * 1. Define the size of the "local storage".  It is
+ *    the map's value_size.
+ *
+ * 2. Maintain a list to keep track of all elems such
+ *    that they can be cleaned up during the map destruction.
+ *
+ * When a bpf local storage is being looked up for a
+ * particular object,  the "bpf_map" pointer is actually used
+ * as the "key" to search in the list of elem in
+ * the respective bpf_local_storage owned by the object.
+ *
+ * e.g. sk->sk_bpf_storage is the mini-map with the "bpf_map" pointer
+ * as the searching key.
+ */
+struct bpf_local_storage_map {
+	struct bpf_map map;
+	/* Lookup elem does not require accessing the map.
+	 *
+	 * Updating/Deleting requires a bucket lock to
+	 * link/unlink the elem from the map.  Having
+	 * multiple buckets to improve contention.
+	 */
+	struct bpf_local_storage_map_bucket *buckets;
+	u32 bucket_log;
+	u16 elem_size;
+	u16 cache_idx;
+};
+
+struct bpf_local_storage_data {
+	/* smap is used as the searching key when looking up
+	 * from the object's bpf_local_storage.
+	 *
+	 * Put it in the same cacheline as the data to minimize
+	 * the number of cachelines access during the cache hit case.
+	 */
+	struct bpf_local_storage_map __rcu *smap;
+	u8 data[] __aligned(8);
+};
+
+/* Linked to bpf_local_storage and bpf_local_storage_map */
+struct bpf_local_storage_elem {
+	struct hlist_node map_node;	/* Linked to bpf_local_storage_map */
+	struct hlist_node snode;	/* Linked to bpf_local_storage */
+	struct bpf_local_storage __rcu *local_storage;
+	struct rcu_head rcu;
+	/* 8 bytes hole */
+	/* The data is stored in aother cacheline to minimize
+	 * the number of cachelines access during a cache hit.
+	 */
+	struct bpf_local_storage_data sdata ____cacheline_aligned;
+};
+
+struct bpf_local_storage {
+	struct bpf_local_storage_data __rcu *cache[BPF_LOCAL_STORAGE_CACHE_SIZE];
+	struct hlist_head list; /* List of bpf_local_storage_elem */
+	void *owner;		/* The object that owns the above "list" of
+				 * bpf_local_storage_elem.
+				 */
+	struct rcu_head rcu;
+	raw_spinlock_t lock;	/* Protect adding/removing from the "list" */
+};
+
+/* U16_MAX is much more than enough for sk local storage
+ * considering a tcp_sock is ~2k.
+ */
+#define BPF_LOCAL_STORAGE_MAX_VALUE_SIZE				       \
+	min_t(u32,                                                             \
+	      (KMALLOC_MAX_SIZE - MAX_BPF_STACK -                              \
+	       sizeof(struct bpf_local_storage_elem)),                         \
+	      (U16_MAX - sizeof(struct bpf_local_storage_elem)))
+
+#define SELEM(_SDATA)                                                          \
+	container_of((_SDATA), struct bpf_local_storage_elem, sdata)
+#define SDATA(_SELEM) (&(_SELEM)->sdata)
+
+#define BPF_LOCAL_STORAGE_CACHE_SIZE	16
+
+struct bpf_local_storage_cache {
+	spinlock_t idx_lock;
+	u64 idx_usage_counts[BPF_LOCAL_STORAGE_CACHE_SIZE];
+};
+
+#define DEFINE_BPF_STORAGE_CACHE(name)				\
+static struct bpf_local_storage_cache name = {			\
+	.idx_lock = __SPIN_LOCK_UNLOCKED(name.idx_lock),	\
+}
+
+u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache);
+void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache,
+				      u16 idx);
+
+/* Helper functions for bpf_local_storage */
+int bpf_local_storage_map_alloc_check(union bpf_attr *attr);
+
+struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr);
+
+struct bpf_local_storage_data *
+bpf_local_storage_lookup(struct bpf_local_storage *local_storage,
+			 struct bpf_local_storage_map *smap,
+			 bool cacheit_lockit);
+
+void bpf_local_storage_map_free(struct bpf_local_storage_map *smap);
+
+int bpf_local_storage_map_check_btf(const struct bpf_map *map,
+				    const struct btf *btf,
+				    const struct btf_type *key_type,
+				    const struct btf_type *value_type);
+
+void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage,
+				   struct bpf_local_storage_elem *selem);
+
+bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage,
+				     struct bpf_local_storage_elem *selem,
+				     bool uncharge_omem);
+
+void bpf_selem_unlink(struct bpf_local_storage_elem *selem);
+
+void bpf_selem_link_map(struct bpf_local_storage_map *smap,
+			struct bpf_local_storage_elem *selem);
+
+void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem);
+
+struct bpf_local_storage_elem *
+bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, void *value,
+		bool charge_mem);
+
+int
+bpf_local_storage_alloc(void *owner,
+			struct bpf_local_storage_map *smap,
+			struct bpf_local_storage_elem *first_selem);
+
+struct bpf_local_storage_data *
+bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap,
+			 void *value, u64 map_flags);
+
+#endif /* _BPF_LOCAL_STORAGE_H */
diff --git a/include/net/bpf_sk_storage.h b/include/net/bpf_sk_storage.h
index 9e631b5466e3..3c516dd07caf 100644
--- a/include/net/bpf_sk_storage.h
+++ b/include/net/bpf_sk_storage.h
@@ -12,6 +12,7 @@
 #include <net/sock.h>
 #include <uapi/linux/sock_diag.h>
 #include <uapi/linux/btf.h>
+#include <linux/bpf_local_storage.h>
 
 struct sock;
 
@@ -26,66 +27,6 @@ struct sk_buff;
 struct nlattr;
 struct sock;
 
-#define BPF_LOCAL_STORAGE_CACHE_SIZE	16
-
-struct bpf_local_storage_cache {
-	spinlock_t idx_lock;
-	u64 idx_usage_counts[BPF_LOCAL_STORAGE_CACHE_SIZE];
-};
-
-#define DEFINE_BPF_STORAGE_CACHE(name)				\
-static struct bpf_local_storage_cache name = {			\
-	.idx_lock = __SPIN_LOCK_UNLOCKED(name.idx_lock),	\
-}
-
-u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache);
-void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache,
-				      u16 idx);
-
-/* Helper functions for bpf_local_storage */
-int bpf_local_storage_map_alloc_check(union bpf_attr *attr);
-
-struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr);
-
-struct bpf_local_storage_data *
-bpf_local_storage_lookup(struct bpf_local_storage *local_storage,
-			 struct bpf_local_storage_map *smap,
-			 bool cacheit_lockit);
-
-void bpf_local_storage_map_free(struct bpf_local_storage_map *smap);
-
-int bpf_local_storage_map_check_btf(const struct bpf_map *map,
-				    const struct btf *btf,
-				    const struct btf_type *key_type,
-				    const struct btf_type *value_type);
-
-void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage,
-				   struct bpf_local_storage_elem *selem);
-
-bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage,
-				     struct bpf_local_storage_elem *selem,
-				     bool uncharge_omem);
-
-void bpf_selem_unlink(struct bpf_local_storage_elem *selem);
-
-void bpf_selem_link_map(struct bpf_local_storage_map *smap,
-			struct bpf_local_storage_elem *selem);
-
-void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem);
-
-struct bpf_local_storage_elem *
-bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, void *value,
-		bool charge_mem);
-
-int
-bpf_local_storage_alloc(void *owner,
-			struct bpf_local_storage_map *smap,
-			struct bpf_local_storage_elem *first_selem);
-
-struct bpf_local_storage_data *
-bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap,
-			 void *value, u64 map_flags);
-
 #ifdef CONFIG_BPF_SYSCALL
 int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk);
 struct bpf_sk_storage_diag *
diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
index 19e137aae40e..6961ff400cba 100644
--- a/kernel/bpf/Makefile
+++ b/kernel/bpf/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_BPF_JIT) += dispatcher.o
 ifeq ($(CONFIG_NET),y)
 obj-$(CONFIG_BPF_SYSCALL) += devmap.o
 obj-$(CONFIG_BPF_SYSCALL) += cpumap.o
+obj-$(CONFIG_BPF_SYSCALL) += bpf_local_storage.o
 obj-$(CONFIG_BPF_SYSCALL) += offload.o
 obj-$(CONFIG_BPF_SYSCALL) += net_namespace.o
 endif
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
new file mode 100644
index 000000000000..ffa7d11fc2bd
--- /dev/null
+++ b/kernel/bpf/bpf_local_storage.c
@@ -0,0 +1,600 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2019 Facebook  */
+#include <linux/rculist.h>
+#include <linux/list.h>
+#include <linux/hash.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/bpf.h>
+#include <linux/btf_ids.h>
+#include <linux/bpf_local_storage.h>
+#include <net/sock.h>
+#include <uapi/linux/sock_diag.h>
+#include <uapi/linux/btf.h>
+
+#define BPF_LOCAL_STORAGE_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_CLONE)
+
+static struct bpf_local_storage_map_bucket *
+select_bucket(struct bpf_local_storage_map *smap,
+	      struct bpf_local_storage_elem *selem)
+{
+	return &smap->buckets[hash_ptr(selem, smap->bucket_log)];
+}
+
+static int mem_charge(struct bpf_local_storage_map *smap, void *owner, u32 size)
+{
+	struct bpf_map *map = &smap->map;
+
+	if (!map->ops->map_local_storage_charge)
+		return 0;
+
+	return map->ops->map_local_storage_charge(smap, owner, size);
+}
+
+static void mem_uncharge(struct bpf_local_storage_map *smap, void *owner,
+			 u32 size)
+{
+	struct bpf_map *map = &smap->map;
+
+	if (map->ops->map_local_storage_uncharge)
+		map->ops->map_local_storage_uncharge(smap, owner, size);
+}
+
+static struct bpf_local_storage __rcu **
+owner_storage(struct bpf_local_storage_map *smap, void *owner)
+{
+	struct bpf_map *map = &smap->map;
+
+	return map->ops->map_owner_storage_ptr(owner);
+}
+
+static bool selem_linked_to_storage(const struct bpf_local_storage_elem *selem)
+{
+	return !hlist_unhashed(&selem->snode);
+}
+
+static bool selem_linked_to_map(const struct bpf_local_storage_elem *selem)
+{
+	return !hlist_unhashed(&selem->map_node);
+}
+
+struct bpf_local_storage_elem *
+bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner,
+		void *value, bool charge_mem)
+{
+	struct bpf_local_storage_elem *selem;
+
+	if (charge_mem && mem_charge(smap, owner, smap->elem_size))
+		return NULL;
+
+	selem = kzalloc(smap->elem_size, GFP_ATOMIC | __GFP_NOWARN);
+	if (selem) {
+		if (value)
+			memcpy(SDATA(selem)->data, value, smap->map.value_size);
+		return selem;
+	}
+
+	if (charge_mem)
+		mem_uncharge(smap, owner, smap->elem_size);
+
+	return NULL;
+}
+
+/* local_storage->lock must be held and selem->local_storage == local_storage.
+ * The caller must ensure selem->smap is still valid to be
+ * dereferenced for its smap->elem_size and smap->cache_idx.
+ */
+bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage,
+				     struct bpf_local_storage_elem *selem,
+				     bool uncharge_mem)
+{
+	struct bpf_local_storage_map *smap;
+	bool free_local_storage;
+	void *owner;
+
+	smap = rcu_dereference(SDATA(selem)->smap);
+	owner = local_storage->owner;
+
+	/* All uncharging on the owner must be done first.
+	 * The owner may be freed once the last selem is unlinked
+	 * from local_storage.
+	 */
+	if (uncharge_mem)
+		mem_uncharge(smap, owner, smap->elem_size);
+
+	free_local_storage = hlist_is_singular_node(&selem->snode,
+						    &local_storage->list);
+	if (free_local_storage) {
+		mem_uncharge(smap, owner, sizeof(struct bpf_local_storage));
+		local_storage->owner = NULL;
+
+		/* After this RCU_INIT, owner may be freed and cannot be used */
+		RCU_INIT_POINTER(*owner_storage(smap, owner), NULL);
+
+		/* local_storage is not freed now.  local_storage->lock is
+		 * still held and raw_spin_unlock_bh(&local_storage->lock)
+		 * will be done by the caller.
+		 *
+		 * Although the unlock will be done under
+		 * rcu_read_lock(),  it is more intutivie to
+		 * read if kfree_rcu(local_storage, rcu) is done
+		 * after the raw_spin_unlock_bh(&local_storage->lock).
+		 *
+		 * Hence, a "bool free_local_storage" is returned
+		 * to the caller which then calls the kfree_rcu()
+		 * after unlock.
+		 */
+	}
+	hlist_del_init_rcu(&selem->snode);
+	if (rcu_access_pointer(local_storage->cache[smap->cache_idx]) ==
+	    SDATA(selem))
+		RCU_INIT_POINTER(local_storage->cache[smap->cache_idx], NULL);
+
+	kfree_rcu(selem, rcu);
+
+	return free_local_storage;
+}
+
+static void __bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem)
+{
+	struct bpf_local_storage *local_storage;
+	bool free_local_storage = false;
+
+	if (unlikely(!selem_linked_to_storage(selem)))
+		/* selem has already been unlinked from sk */
+		return;
+
+	local_storage = rcu_dereference(selem->local_storage);
+	raw_spin_lock_bh(&local_storage->lock);
+	if (likely(selem_linked_to_storage(selem)))
+		free_local_storage = bpf_selem_unlink_storage_nolock(
+			local_storage, selem, true);
+	raw_spin_unlock_bh(&local_storage->lock);
+
+	if (free_local_storage)
+		kfree_rcu(local_storage, rcu);
+}
+
+void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage,
+				   struct bpf_local_storage_elem *selem)
+{
+	RCU_INIT_POINTER(selem->local_storage, local_storage);
+	hlist_add_head(&selem->snode, &local_storage->list);
+}
+
+void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem)
+{
+	struct bpf_local_storage_map *smap;
+	struct bpf_local_storage_map_bucket *b;
+
+	if (unlikely(!selem_linked_to_map(selem)))
+		/* selem has already be unlinked from smap */
+		return;
+
+	smap = rcu_dereference(SDATA(selem)->smap);
+	b = select_bucket(smap, selem);
+	raw_spin_lock_bh(&b->lock);
+	if (likely(selem_linked_to_map(selem)))
+		hlist_del_init_rcu(&selem->map_node);
+	raw_spin_unlock_bh(&b->lock);
+}
+
+void bpf_selem_link_map(struct bpf_local_storage_map *smap,
+			struct bpf_local_storage_elem *selem)
+{
+	struct bpf_local_storage_map_bucket *b = select_bucket(smap, selem);
+
+	raw_spin_lock_bh(&b->lock);
+	RCU_INIT_POINTER(SDATA(selem)->smap, smap);
+	hlist_add_head_rcu(&selem->map_node, &b->list);
+	raw_spin_unlock_bh(&b->lock);
+}
+
+void bpf_selem_unlink(struct bpf_local_storage_elem *selem)
+{
+	/* Always unlink from map before unlinking from local_storage
+	 * because selem will be freed after successfully unlinked from
+	 * the local_storage.
+	 */
+	bpf_selem_unlink_map(selem);
+	__bpf_selem_unlink_storage(selem);
+}
+
+struct bpf_local_storage_data *
+bpf_local_storage_lookup(struct bpf_local_storage *local_storage,
+			 struct bpf_local_storage_map *smap,
+			 bool cacheit_lockit)
+{
+	struct bpf_local_storage_data *sdata;
+	struct bpf_local_storage_elem *selem;
+
+	/* Fast path (cache hit) */
+	sdata = rcu_dereference(local_storage->cache[smap->cache_idx]);
+	if (sdata && rcu_access_pointer(sdata->smap) == smap)
+		return sdata;
+
+	/* Slow path (cache miss) */
+	hlist_for_each_entry_rcu(selem, &local_storage->list, snode)
+		if (rcu_access_pointer(SDATA(selem)->smap) == smap)
+			break;
+
+	if (!selem)
+		return NULL;
+
+	sdata = SDATA(selem);
+	if (cacheit_lockit) {
+		/* spinlock is needed to avoid racing with the
+		 * parallel delete.  Otherwise, publishing an already
+		 * deleted sdata to the cache will become a use-after-free
+		 * problem in the next bpf_local_storage_lookup().
+		 */
+		raw_spin_lock_bh(&local_storage->lock);
+		if (selem_linked_to_storage(selem))
+			rcu_assign_pointer(local_storage->cache[smap->cache_idx],
+					   sdata);
+		raw_spin_unlock_bh(&local_storage->lock);
+	}
+
+	return sdata;
+}
+
+static int check_flags(const struct bpf_local_storage_data *old_sdata,
+		       u64 map_flags)
+{
+	if (old_sdata && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
+		/* elem already exists */
+		return -EEXIST;
+
+	if (!old_sdata && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
+		/* elem doesn't exist, cannot update it */
+		return -ENOENT;
+
+	return 0;
+}
+
+int bpf_local_storage_alloc(void *owner,
+			    struct bpf_local_storage_map *smap,
+			    struct bpf_local_storage_elem *first_selem)
+{
+	struct bpf_local_storage *prev_storage, *storage;
+	struct bpf_local_storage **owner_storage_ptr;
+	int err;
+
+	err = mem_charge(smap, owner, sizeof(*storage));
+	if (err)
+		return err;
+
+	storage = kzalloc(sizeof(*storage), GFP_ATOMIC | __GFP_NOWARN);
+	if (!storage) {
+		err = -ENOMEM;
+		goto uncharge;
+	}
+
+	INIT_HLIST_HEAD(&storage->list);
+	raw_spin_lock_init(&storage->lock);
+	storage->owner = owner;
+
+	bpf_selem_link_storage_nolock(storage, first_selem);
+	bpf_selem_link_map(smap, first_selem);
+
+	owner_storage_ptr =
+		(struct bpf_local_storage **)owner_storage(smap, owner);
+	/* Publish storage to the owner.
+	 * Instead of using any lock of the kernel object (i.e. owner),
+	 * cmpxchg will work with any kernel object regardless what
+	 * the running context is, bh, irq...etc.
+	 *
+	 * From now on, the owner->storage pointer (e.g. sk->sk_bpf_storage)
+	 * is protected by the storage->lock.  Hence, when freeing
+	 * the owner->storage, the storage->lock must be held before
+	 * setting owner->storage ptr to NULL.
+	 */
+	prev_storage = cmpxchg(owner_storage_ptr, NULL, storage);
+	if (unlikely(prev_storage)) {
+		bpf_selem_unlink_map(first_selem);
+		err = -EAGAIN;
+		goto uncharge;
+
+		/* Note that even first_selem was linked to smap's
+		 * bucket->list, first_selem can be freed immediately
+		 * (instead of kfree_rcu) because
+		 * bpf_local_storage_map_free() does a
+		 * synchronize_rcu() before walking the bucket->list.
+		 * Hence, no one is accessing selem from the
+		 * bucket->list under rcu_read_lock().
+		 */
+	}
+
+	return 0;
+
+uncharge:
+	kfree(storage);
+	mem_uncharge(smap, owner, sizeof(*storage));
+	return err;
+}
+
+/* sk cannot be going away because it is linking new elem
+ * to sk->sk_bpf_storage. (i.e. sk->sk_refcnt cannot be 0).
+ * Otherwise, it will become a leak (and other memory issues
+ * during map destruction).
+ */
+struct bpf_local_storage_data *
+bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap,
+			 void *value, u64 map_flags)
+{
+	struct bpf_local_storage_data *old_sdata = NULL;
+	struct bpf_local_storage_elem *selem;
+	struct bpf_local_storage *local_storage;
+	int err;
+
+	/* BPF_EXIST and BPF_NOEXIST cannot be both set */
+	if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST) ||
+	    /* BPF_F_LOCK can only be used in a value with spin_lock */
+	    unlikely((map_flags & BPF_F_LOCK) &&
+		     !map_value_has_spin_lock(&smap->map)))
+		return ERR_PTR(-EINVAL);
+
+	local_storage = rcu_dereference(*owner_storage(smap, owner));
+	if (!local_storage || hlist_empty(&local_storage->list)) {
+		/* Very first elem for the owner */
+		err = check_flags(NULL, map_flags);
+		if (err)
+			return ERR_PTR(err);
+
+		selem = bpf_selem_alloc(smap, owner, value, true);
+		if (!selem)
+			return ERR_PTR(-ENOMEM);
+
+		err = bpf_local_storage_alloc(owner, smap, selem);
+		if (err) {
+			kfree(selem);
+			mem_uncharge(smap, owner, smap->elem_size);
+			return ERR_PTR(err);
+		}
+
+		return SDATA(selem);
+	}
+
+	if ((map_flags & BPF_F_LOCK) && !(map_flags & BPF_NOEXIST)) {
+		/* Hoping to find an old_sdata to do inline update
+		 * such that it can avoid taking the local_storage->lock
+		 * and changing the lists.
+		 */
+		old_sdata =
+			bpf_local_storage_lookup(local_storage, smap, false);
+		err = check_flags(old_sdata, map_flags);
+		if (err)
+			return ERR_PTR(err);
+		if (old_sdata && selem_linked_to_storage(SELEM(old_sdata))) {
+			copy_map_value_locked(&smap->map, old_sdata->data,
+					      value, false);
+			return old_sdata;
+		}
+	}
+
+	raw_spin_lock_bh(&local_storage->lock);
+
+	/* Recheck local_storage->list under local_storage->lock */
+	if (unlikely(hlist_empty(&local_storage->list))) {
+		/* A parallel del is happening and local_storage is going
+		 * away.  It has just been checked before, so very
+		 * unlikely.  Return instead of retry to keep things
+		 * simple.
+		 */
+		err = -EAGAIN;
+		goto unlock_err;
+	}
+
+	old_sdata = bpf_local_storage_lookup(local_storage, smap, false);
+	err = check_flags(old_sdata, map_flags);
+	if (err)
+		goto unlock_err;
+
+	if (old_sdata && (map_flags & BPF_F_LOCK)) {
+		copy_map_value_locked(&smap->map, old_sdata->data, value,
+				      false);
+		selem = SELEM(old_sdata);
+		goto unlock;
+	}
+
+	/* local_storage->lock is held.  Hence, we are sure
+	 * we can unlink and uncharge the old_sdata successfully
+	 * later.  Hence, instead of charging the new selem now
+	 * and then uncharge the old selem later (which may cause
+	 * a potential but unnecessary charge failure),  avoid taking
+	 * a charge at all here (the "!old_sdata" check) and the
+	 * old_sdata will not be uncharged later during
+	 * bpf_selem_unlink_storage_nolock().
+	 */
+	selem = bpf_selem_alloc(smap, owner, value, !old_sdata);
+	if (!selem) {
+		err = -ENOMEM;
+		goto unlock_err;
+	}
+
+	/* First, link the new selem to the map */
+	bpf_selem_link_map(smap, selem);
+
+	/* Second, link (and publish) the new selem to local_storage */
+	bpf_selem_link_storage_nolock(local_storage, selem);
+
+	/* Third, remove old selem, SELEM(old_sdata) */
+	if (old_sdata) {
+		bpf_selem_unlink_map(SELEM(old_sdata));
+		bpf_selem_unlink_storage_nolock(local_storage, SELEM(old_sdata),
+						false);
+	}
+
+unlock:
+	raw_spin_unlock_bh(&local_storage->lock);
+	return SDATA(selem);
+
+unlock_err:
+	raw_spin_unlock_bh(&local_storage->lock);
+	return ERR_PTR(err);
+}
+
+u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache)
+{
+	u64 min_usage = U64_MAX;
+	u16 i, res = 0;
+
+	spin_lock(&cache->idx_lock);
+
+	for (i = 0; i < BPF_LOCAL_STORAGE_CACHE_SIZE; i++) {
+		if (cache->idx_usage_counts[i] < min_usage) {
+			min_usage = cache->idx_usage_counts[i];
+			res = i;
+
+			/* Found a free cache_idx */
+			if (!min_usage)
+				break;
+		}
+	}
+	cache->idx_usage_counts[res]++;
+
+	spin_unlock(&cache->idx_lock);
+
+	return res;
+}
+
+void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache,
+				      u16 idx)
+{
+	spin_lock(&cache->idx_lock);
+	cache->idx_usage_counts[idx]--;
+	spin_unlock(&cache->idx_lock);
+}
+
+void bpf_local_storage_map_free(struct bpf_local_storage_map *smap)
+{
+	struct bpf_local_storage_elem *selem;
+	struct bpf_local_storage_map_bucket *b;
+	unsigned int i;
+
+	/* Note that this map might be concurrently cloned from
+	 * bpf_sk_storage_clone. Wait for any existing bpf_sk_storage_clone
+	 * RCU read section to finish before proceeding. New RCU
+	 * read sections should be prevented via bpf_map_inc_not_zero.
+	 */
+	synchronize_rcu();
+
+	/* bpf prog and the userspace can no longer access this map
+	 * now.  No new selem (of this map) can be added
+	 * to the owner->storage or to the map bucket's list.
+	 *
+	 * The elem of this map can be cleaned up here
+	 * or when the storage is freed e.g.
+	 * by bpf_sk_storage_free() during __sk_destruct().
+	 */
+	for (i = 0; i < (1U << smap->bucket_log); i++) {
+		b = &smap->buckets[i];
+
+		rcu_read_lock();
+		/* No one is adding to b->list now */
+		while ((selem = hlist_entry_safe(
+				rcu_dereference_raw(hlist_first_rcu(&b->list)),
+				struct bpf_local_storage_elem, map_node))) {
+			bpf_selem_unlink(selem);
+			cond_resched_rcu();
+		}
+		rcu_read_unlock();
+	}
+
+	/* While freeing the storage we may still need to access the map.
+	 *
+	 * e.g. when bpf_sk_storage_free() has unlinked selem from the map
+	 * which then made the above while((selem = ...)) loop
+	 * exit immediately.
+	 *
+	 * However, while freeing the storage one still needs to access the
+	 * smap->elem_size to do the uncharging in
+	 * bpf_selem_unlink_storage_nolock().
+	 *
+	 * Hence, wait another rcu grace period for the storage to be freed.
+	 */
+	synchronize_rcu();
+
+	kvfree(smap->buckets);
+	kfree(smap);
+}
+
+int bpf_local_storage_map_alloc_check(union bpf_attr *attr)
+{
+	if (attr->map_flags & ~BPF_LOCAL_STORAGE_CREATE_FLAG_MASK ||
+	    !(attr->map_flags & BPF_F_NO_PREALLOC) ||
+	    attr->max_entries ||
+	    attr->key_size != sizeof(int) || !attr->value_size ||
+	    /* Enforce BTF for userspace sk dumping */
+	    !attr->btf_key_type_id || !attr->btf_value_type_id)
+		return -EINVAL;
+
+	if (!bpf_capable())
+		return -EPERM;
+
+	if (attr->value_size > BPF_LOCAL_STORAGE_MAX_VALUE_SIZE)
+		return -E2BIG;
+
+	return 0;
+}
+
+struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_local_storage_map *smap;
+	unsigned int i;
+	u32 nbuckets;
+	u64 cost;
+	int ret;
+
+	smap = kzalloc(sizeof(*smap), GFP_USER | __GFP_NOWARN);
+	if (!smap)
+		return ERR_PTR(-ENOMEM);
+	bpf_map_init_from_attr(&smap->map, attr);
+
+	nbuckets = roundup_pow_of_two(num_possible_cpus());
+	/* Use at least 2 buckets, select_bucket() is undefined behavior with 1 bucket */
+	nbuckets = max_t(u32, 2, nbuckets);
+	smap->bucket_log = ilog2(nbuckets);
+	cost = sizeof(*smap->buckets) * nbuckets + sizeof(*smap);
+
+	ret = bpf_map_charge_init(&smap->map.memory, cost);
+	if (ret < 0) {
+		kfree(smap);
+		return ERR_PTR(ret);
+	}
+
+	smap->buckets = kvcalloc(sizeof(*smap->buckets), nbuckets,
+				 GFP_USER | __GFP_NOWARN);
+	if (!smap->buckets) {
+		bpf_map_charge_finish(&smap->map.memory);
+		kfree(smap);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	for (i = 0; i < nbuckets; i++) {
+		INIT_HLIST_HEAD(&smap->buckets[i].list);
+		raw_spin_lock_init(&smap->buckets[i].lock);
+	}
+
+	smap->elem_size =
+		sizeof(struct bpf_local_storage_elem) + attr->value_size;
+
+	return smap;
+}
+
+int bpf_local_storage_map_check_btf(const struct bpf_map *map,
+				    const struct btf *btf,
+				    const struct btf_type *key_type,
+				    const struct btf_type *value_type)
+{
+	u32 int_data;
+
+	if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
+		return -EINVAL;
+
+	int_data = *(u32 *)(key_type + 1);
+	if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data))
+		return -EINVAL;
+
+	return 0;
+}
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index cd8b7017913b..f29d9a9b4ea4 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -7,97 +7,14 @@
 #include <linux/spinlock.h>
 #include <linux/bpf.h>
 #include <linux/btf_ids.h>
+#include <linux/bpf_local_storage.h>
 #include <net/bpf_sk_storage.h>
 #include <net/sock.h>
 #include <uapi/linux/sock_diag.h>
 #include <uapi/linux/btf.h>
 
-#define BPF_LOCAL_STORAGE_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_CLONE)
-
 DEFINE_BPF_STORAGE_CACHE(sk_cache);
 
-struct bpf_local_storage_map_bucket {
-	struct hlist_head list;
-	raw_spinlock_t lock;
-};
-
-/* Thp map is not the primary owner of a bpf_local_storage_elem.
- * Instead, the container object (eg. sk->sk_bpf_storage) is.
- *
- * The map (bpf_local_storage_map) is for two purposes
- * 1. Define the size of the "local storage".  It is
- *    the map's value_size.
- *
- * 2. Maintain a list to keep track of all elems such
- *    that they can be cleaned up during the map destruction.
- *
- * When a bpf local storage is being looked up for a
- * particular object,  the "bpf_map" pointer is actually used
- * as the "key" to search in the list of elem in
- * the respective bpf_local_storage owned by the object.
- *
- * e.g. sk->sk_bpf_storage is the mini-map with the "bpf_map" pointer
- * as the searching key.
- */
-struct bpf_local_storage_map {
-	struct bpf_map map;
-	/* Lookup elem does not require accessing the map.
-	 *
-	 * Updating/Deleting requires a bucket lock to
-	 * link/unlink the elem from the map.  Having
-	 * multiple buckets to improve contention.
-	 */
-	struct bpf_local_storage_map_bucket *buckets;
-	u32 bucket_log;
-	u16 elem_size;
-	u16 cache_idx;
-};
-
-struct bpf_local_storage_data {
-	/* smap is used as the searching key when looking up
-	 * from the object's bpf_local_storage.
-	 *
-	 * Put it in the same cacheline as the data to minimize
-	 * the number of cachelines access during the cache hit case.
-	 */
-	struct bpf_local_storage_map __rcu *smap;
-	u8 data[] __aligned(8);
-};
-
-/* Linked to bpf_local_storage and bpf_local_storage_map */
-struct bpf_local_storage_elem {
-	struct hlist_node map_node;	/* Linked to bpf_local_storage_map */
-	struct hlist_node snode;	/* Linked to bpf_local_storage */
-	struct bpf_local_storage __rcu *local_storage;
-	struct rcu_head rcu;
-	/* 8 bytes hole */
-	/* The data is stored in aother cacheline to minimize
-	 * the number of cachelines access during a cache hit.
-	 */
-	struct bpf_local_storage_data sdata ____cacheline_aligned;
-};
-
-#define SELEM(_SDATA)							\
-	container_of((_SDATA), struct bpf_local_storage_elem, sdata)
-#define SDATA(_SELEM) (&(_SELEM)->sdata)
-
-struct bpf_local_storage {
-	struct bpf_local_storage_data __rcu *cache[BPF_LOCAL_STORAGE_CACHE_SIZE];
-	struct hlist_head list; /* List of bpf_local_storage_elem */
-	void *owner;		/* The object that owns the above "list" of
-				 * bpf_local_storage_elem.
-				 */
-	struct rcu_head rcu;
-	raw_spinlock_t lock;	/* Protect adding/removing from the "list" */
-};
-
-static struct bpf_local_storage_map_bucket *
-select_bucket(struct bpf_local_storage_map *smap,
-	      struct bpf_local_storage_elem *selem)
-{
-	return &smap->buckets[hash_ptr(selem, smap->bucket_log)];
-}
-
 static int omem_charge(struct sock *sk, unsigned int size)
 {
 	/* same check as in sock_kmalloc() */
@@ -110,223 +27,6 @@ static int omem_charge(struct sock *sk, unsigned int size)
 	return -ENOMEM;
 }
 
-static int mem_charge(struct bpf_local_storage_map *smap, void *owner, u32 size)
-{
-	struct bpf_map *map = &smap->map;
-
-	if (!map->ops->map_local_storage_charge)
-		return 0;
-
-	return map->ops->map_local_storage_charge(smap, owner, size);
-}
-
-static void mem_uncharge(struct bpf_local_storage_map *smap, void *owner,
-			 u32 size)
-{
-	struct bpf_map *map = &smap->map;
-
-	if (map->ops->map_local_storage_uncharge)
-		map->ops->map_local_storage_uncharge(smap, owner, size);
-}
-
-static struct bpf_local_storage __rcu **
-owner_storage(struct bpf_local_storage_map *smap, void *owner)
-{
-	struct bpf_map *map = &smap->map;
-
-	return map->ops->map_owner_storage_ptr(owner);
-}
-
-static bool selem_linked_to_storage(const struct bpf_local_storage_elem *selem)
-{
-	return !hlist_unhashed(&selem->snode);
-}
-
-static bool selem_linked_to_map(const struct bpf_local_storage_elem *selem)
-{
-	return !hlist_unhashed(&selem->map_node);
-}
-
-struct bpf_local_storage_elem *
-bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner,
-		void *value, bool charge_mem)
-{
-	struct bpf_local_storage_elem *selem;
-
-	if (charge_mem && mem_charge(smap, owner, smap->elem_size))
-		return NULL;
-
-	selem = kzalloc(smap->elem_size, GFP_ATOMIC | __GFP_NOWARN);
-	if (selem) {
-		if (value)
-			memcpy(SDATA(selem)->data, value, smap->map.value_size);
-		return selem;
-	}
-
-	if (charge_mem)
-		mem_uncharge(smap, owner, smap->elem_size);
-
-	return NULL;
-}
-
-/* local_storage->lock must be held and selem->local_storage == local_storage.
- * The caller must ensure selem->smap is still valid to be
- * dereferenced for its smap->elem_size and smap->cache_idx.
- */
-bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage,
-				     struct bpf_local_storage_elem *selem,
-				     bool uncharge_mem)
-{
-	struct bpf_local_storage_map *smap;
-	bool free_local_storage;
-	void *owner;
-
-	smap = rcu_dereference(SDATA(selem)->smap);
-	owner = local_storage->owner;
-
-	/* All uncharging on the owner must be done first.
-	 * The owner may be freed once the last selem is unlinked
-	 * from local_storage.
-	 */
-	if (uncharge_mem)
-		mem_uncharge(smap, owner, smap->elem_size);
-
-	free_local_storage = hlist_is_singular_node(&selem->snode,
-						    &local_storage->list);
-	if (free_local_storage) {
-		mem_uncharge(smap, owner, sizeof(struct bpf_local_storage));
-		local_storage->owner = NULL;
-
-		/* After this RCU_INIT, owner may be freed and cannot be used */
-		RCU_INIT_POINTER(*owner_storage(smap, owner), NULL);
-
-		/* local_storage is not freed now.  local_storage->lock is
-		 * still held and raw_spin_unlock_bh(&local_storage->lock)
-		 * will be done by the caller.
-		 *
-		 * Although the unlock will be done under
-		 * rcu_read_lock(),  it is more intutivie to
-		 * read if kfree_rcu(local_storage, rcu) is done
-		 * after the raw_spin_unlock_bh(&local_storage->lock).
-		 *
-		 * Hence, a "bool free_local_storage" is returned
-		 * to the caller which then calls the kfree_rcu()
-		 * after unlock.
-		 */
-	}
-	hlist_del_init_rcu(&selem->snode);
-	if (rcu_access_pointer(local_storage->cache[smap->cache_idx]) ==
-	    SDATA(selem))
-		RCU_INIT_POINTER(local_storage->cache[smap->cache_idx], NULL);
-
-	kfree_rcu(selem, rcu);
-
-	return free_local_storage;
-}
-
-static void __bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem)
-{
-	struct bpf_local_storage *local_storage;
-	bool free_local_storage = false;
-
-	if (unlikely(!selem_linked_to_storage(selem)))
-		/* selem has already been unlinked from sk */
-		return;
-
-	local_storage = rcu_dereference(selem->local_storage);
-	raw_spin_lock_bh(&local_storage->lock);
-	if (likely(selem_linked_to_storage(selem)))
-		free_local_storage = bpf_selem_unlink_storage_nolock(
-			local_storage, selem, true);
-	raw_spin_unlock_bh(&local_storage->lock);
-
-	if (free_local_storage)
-		kfree_rcu(local_storage, rcu);
-}
-
-void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage,
-				   struct bpf_local_storage_elem *selem)
-{
-	RCU_INIT_POINTER(selem->local_storage, local_storage);
-	hlist_add_head(&selem->snode, &local_storage->list);
-}
-
-void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem)
-{
-	struct bpf_local_storage_map *smap;
-	struct bpf_local_storage_map_bucket *b;
-
-	if (unlikely(!selem_linked_to_map(selem)))
-		/* selem has already be unlinked from smap */
-		return;
-
-	smap = rcu_dereference(SDATA(selem)->smap);
-	b = select_bucket(smap, selem);
-	raw_spin_lock_bh(&b->lock);
-	if (likely(selem_linked_to_map(selem)))
-		hlist_del_init_rcu(&selem->map_node);
-	raw_spin_unlock_bh(&b->lock);
-}
-
-void bpf_selem_link_map(struct bpf_local_storage_map *smap,
-			struct bpf_local_storage_elem *selem)
-{
-	struct bpf_local_storage_map_bucket *b = select_bucket(smap, selem);
-
-	raw_spin_lock_bh(&b->lock);
-	RCU_INIT_POINTER(SDATA(selem)->smap, smap);
-	hlist_add_head_rcu(&selem->map_node, &b->list);
-	raw_spin_unlock_bh(&b->lock);
-}
-
-void bpf_selem_unlink(struct bpf_local_storage_elem *selem)
-{
-	/* Always unlink from map before unlinking from local_storage
-	 * because selem will be freed after successfully unlinked from
-	 * the local_storage.
-	 */
-	bpf_selem_unlink_map(selem);
-	__bpf_selem_unlink_storage(selem);
-}
-
-struct bpf_local_storage_data *
-bpf_local_storage_lookup(struct bpf_local_storage *local_storage,
-			 struct bpf_local_storage_map *smap,
-			 bool cacheit_lockit)
-{
-	struct bpf_local_storage_data *sdata;
-	struct bpf_local_storage_elem *selem;
-
-	/* Fast path (cache hit) */
-	sdata = rcu_dereference(local_storage->cache[smap->cache_idx]);
-	if (sdata && rcu_access_pointer(sdata->smap) == smap)
-		return sdata;
-
-	/* Slow path (cache miss) */
-	hlist_for_each_entry_rcu(selem, &local_storage->list, snode)
-		if (rcu_access_pointer(SDATA(selem)->smap) == smap)
-			break;
-
-	if (!selem)
-		return NULL;
-
-	sdata = SDATA(selem);
-	if (cacheit_lockit) {
-		/* spinlock is needed to avoid racing with the
-		 * parallel delete.  Otherwise, publishing an already
-		 * deleted sdata to the cache will become a use-after-free
-		 * problem in the next bpf_local_storage_lookup().
-		 */
-		raw_spin_lock_bh(&local_storage->lock);
-		if (selem_linked_to_storage(selem))
-			rcu_assign_pointer(local_storage->cache[smap->cache_idx],
-					   sdata);
-		raw_spin_unlock_bh(&local_storage->lock);
-	}
-
-	return sdata;
-}
-
 static struct bpf_local_storage_data *
 sk_storage_lookup(struct sock *sk, struct bpf_map *map, bool cacheit_lockit)
 {
@@ -341,202 +41,6 @@ sk_storage_lookup(struct sock *sk, struct bpf_map *map, bool cacheit_lockit)
 	return bpf_local_storage_lookup(sk_storage, smap, cacheit_lockit);
 }
 
-static int check_flags(const struct bpf_local_storage_data *old_sdata,
-		       u64 map_flags)
-{
-	if (old_sdata && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
-		/* elem already exists */
-		return -EEXIST;
-
-	if (!old_sdata && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
-		/* elem doesn't exist, cannot update it */
-		return -ENOENT;
-
-	return 0;
-}
-
-int bpf_local_storage_alloc(void *owner,
-			    struct bpf_local_storage_map *smap,
-			    struct bpf_local_storage_elem *first_selem)
-{
-	struct bpf_local_storage *prev_storage, *storage;
-	struct bpf_local_storage **owner_storage_ptr;
-	int err;
-
-	err = mem_charge(smap, owner, sizeof(*storage));
-	if (err)
-		return err;
-
-	storage = kzalloc(sizeof(*storage), GFP_ATOMIC | __GFP_NOWARN);
-	if (!storage) {
-		err = -ENOMEM;
-		goto uncharge;
-	}
-
-	INIT_HLIST_HEAD(&storage->list);
-	raw_spin_lock_init(&storage->lock);
-	storage->owner = owner;
-
-	bpf_selem_link_storage_nolock(storage, first_selem);
-	bpf_selem_link_map(smap, first_selem);
-
-	owner_storage_ptr =
-		(struct bpf_local_storage **)owner_storage(smap, owner);
-	/* Publish storage to the owner.
-	 * Instead of using any lock of the kernel object (i.e. owner),
-	 * cmpxchg will work with any kernel object regardless what
-	 * the running context is, bh, irq...etc.
-	 *
-	 * From now on, the owner->storage pointer (e.g. sk->sk_bpf_storage)
-	 * is protected by the storage->lock.  Hence, when freeing
-	 * the owner->storage, the storage->lock must be held before
-	 * setting owner->storage ptr to NULL.
-	 */
-	prev_storage = cmpxchg(owner_storage_ptr, NULL, storage);
-	if (unlikely(prev_storage)) {
-		bpf_selem_unlink_map(first_selem);
-		err = -EAGAIN;
-		goto uncharge;
-
-		/* Note that even first_selem was linked to smap's
-		 * bucket->list, first_selem can be freed immediately
-		 * (instead of kfree_rcu) because
-		 * bpf_local_storage_map_free() does a
-		 * synchronize_rcu() before walking the bucket->list.
-		 * Hence, no one is accessing selem from the
-		 * bucket->list under rcu_read_lock().
-		 */
-	}
-
-	return 0;
-
-uncharge:
-	kfree(storage);
-	mem_uncharge(smap, owner, sizeof(*storage));
-	return err;
-}
-
-/* sk cannot be going away because it is linking new elem
- * to sk->sk_bpf_storage. (i.e. sk->sk_refcnt cannot be 0).
- * Otherwise, it will become a leak (and other memory issues
- * during map destruction).
- */
-struct bpf_local_storage_data *
-bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap,
-			 void *value, u64 map_flags)
-{
-	struct bpf_local_storage_data *old_sdata = NULL;
-	struct bpf_local_storage_elem *selem;
-	struct bpf_local_storage *local_storage;
-	int err;
-
-	/* BPF_EXIST and BPF_NOEXIST cannot be both set */
-	if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST) ||
-	    /* BPF_F_LOCK can only be used in a value with spin_lock */
-	    unlikely((map_flags & BPF_F_LOCK) &&
-		     !map_value_has_spin_lock(&smap->map)))
-		return ERR_PTR(-EINVAL);
-
-	local_storage = rcu_dereference(*owner_storage(smap, owner));
-	if (!local_storage || hlist_empty(&local_storage->list)) {
-		/* Very first elem for the owner */
-		err = check_flags(NULL, map_flags);
-		if (err)
-			return ERR_PTR(err);
-
-		selem = bpf_selem_alloc(smap, owner, value, true);
-		if (!selem)
-			return ERR_PTR(-ENOMEM);
-
-		err = bpf_local_storage_alloc(owner, smap, selem);
-		if (err) {
-			kfree(selem);
-			mem_uncharge(smap, owner, smap->elem_size);
-			return ERR_PTR(err);
-		}
-
-		return SDATA(selem);
-	}
-
-	if ((map_flags & BPF_F_LOCK) && !(map_flags & BPF_NOEXIST)) {
-		/* Hoping to find an old_sdata to do inline update
-		 * such that it can avoid taking the local_storage->lock
-		 * and changing the lists.
-		 */
-		old_sdata =
-			bpf_local_storage_lookup(local_storage, smap, false);
-		err = check_flags(old_sdata, map_flags);
-		if (err)
-			return ERR_PTR(err);
-		if (old_sdata && selem_linked_to_storage(SELEM(old_sdata))) {
-			copy_map_value_locked(&smap->map, old_sdata->data,
-					      value, false);
-			return old_sdata;
-		}
-	}
-
-	raw_spin_lock_bh(&local_storage->lock);
-
-	/* Recheck local_storage->list under local_storage->lock */
-	if (unlikely(hlist_empty(&local_storage->list))) {
-		/* A parallel del is happening and local_storage is going
-		 * away.  It has just been checked before, so very
-		 * unlikely.  Return instead of retry to keep things
-		 * simple.
-		 */
-		err = -EAGAIN;
-		goto unlock_err;
-	}
-
-	old_sdata = bpf_local_storage_lookup(local_storage, smap, false);
-	err = check_flags(old_sdata, map_flags);
-	if (err)
-		goto unlock_err;
-
-	if (old_sdata && (map_flags & BPF_F_LOCK)) {
-		copy_map_value_locked(&smap->map, old_sdata->data, value,
-				      false);
-		selem = SELEM(old_sdata);
-		goto unlock;
-	}
-
-	/* local_storage->lock is held.  Hence, we are sure
-	 * we can unlink and uncharge the old_sdata successfully
-	 * later.  Hence, instead of charging the new selem now
-	 * and then uncharge the old selem later (which may cause
-	 * a potential but unnecessary charge failure),  avoid taking
-	 * a charge at all here (the "!old_sdata" check) and the
-	 * old_sdata will not be uncharged later during
-	 * bpf_selem_unlink_storage_nolock().
-	 */
-	selem = bpf_selem_alloc(smap, owner, value, !old_sdata);
-	if (!selem) {
-		err = -ENOMEM;
-		goto unlock_err;
-	}
-
-	/* First, link the new selem to the map */
-	bpf_selem_link_map(smap, selem);
-
-	/* Second, link (and publish) the new selem to local_storage */
-	bpf_selem_link_storage_nolock(local_storage, selem);
-
-	/* Third, remove old selem, SELEM(old_sdata) */
-	if (old_sdata) {
-		bpf_selem_unlink_map(SELEM(old_sdata));
-		bpf_selem_unlink_storage_nolock(local_storage, SELEM(old_sdata),
-						false);
-	}
-
-unlock:
-	raw_spin_unlock_bh(&local_storage->lock);
-	return SDATA(selem);
-
-unlock_err:
-	raw_spin_unlock_bh(&local_storage->lock);
-	return ERR_PTR(err);
-}
-
 static int sk_storage_delete(struct sock *sk, struct bpf_map *map)
 {
 	struct bpf_local_storage_data *sdata;
@@ -550,38 +54,6 @@ static int sk_storage_delete(struct sock *sk, struct bpf_map *map)
 	return 0;
 }
 
-u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache)
-{
-	u64 min_usage = U64_MAX;
-	u16 i, res = 0;
-
-	spin_lock(&cache->idx_lock);
-
-	for (i = 0; i < BPF_LOCAL_STORAGE_CACHE_SIZE; i++) {
-		if (cache->idx_usage_counts[i] < min_usage) {
-			min_usage = cache->idx_usage_counts[i];
-			res = i;
-
-			/* Found a free cache_idx */
-			if (!min_usage)
-				break;
-		}
-	}
-	cache->idx_usage_counts[res]++;
-
-	spin_unlock(&cache->idx_lock);
-
-	return res;
-}
-
-void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache,
-				      u16 idx)
-{
-	spin_lock(&cache->idx_lock);
-	cache->idx_usage_counts[idx]--;
-	spin_unlock(&cache->idx_lock);
-}
-
 /* Called by __sk_destruct() & bpf_sk_storage_clone() */
 void bpf_sk_storage_free(struct sock *sk)
 {
@@ -622,59 +94,6 @@ void bpf_sk_storage_free(struct sock *sk)
 		kfree_rcu(sk_storage, rcu);
 }
 
-void bpf_local_storage_map_free(struct bpf_local_storage_map *smap)
-{
-	struct bpf_local_storage_elem *selem;
-	struct bpf_local_storage_map_bucket *b;
-	unsigned int i;
-
-	/* Note that this map might be concurrently cloned from
-	 * bpf_sk_storage_clone. Wait for any existing bpf_sk_storage_clone
-	 * RCU read section to finish before proceeding. New RCU
-	 * read sections should be prevented via bpf_map_inc_not_zero.
-	 */
-	synchronize_rcu();
-
-	/* bpf prog and the userspace can no longer access this map
-	 * now.  No new selem (of this map) can be added
-	 * to the owner->storage or to the map bucket's list.
-	 *
-	 * The elem of this map can be cleaned up here
-	 * or when the storage is freed e.g.
-	 * by bpf_sk_storage_free() during __sk_destruct().
-	 */
-	for (i = 0; i < (1U << smap->bucket_log); i++) {
-		b = &smap->buckets[i];
-
-		rcu_read_lock();
-		/* No one is adding to b->list now */
-		while ((selem = hlist_entry_safe(
-				rcu_dereference_raw(hlist_first_rcu(&b->list)),
-				struct bpf_local_storage_elem, map_node))) {
-			bpf_selem_unlink(selem);
-			cond_resched_rcu();
-		}
-		rcu_read_unlock();
-	}
-
-	/* While freeing the storage we may still need to access the map.
-	 *
-	 * e.g. when bpf_sk_storage_free() has unlinked selem from the map
-	 * which then made the above while((selem = ...)) loop
-	 * exit immediately.
-	 *
-	 * However, while freeing the storage one still needs to access the
-	 * smap->elem_size to do the uncharging in
-	 * bpf_selem_unlink_storage_nolock().
-	 *
-	 * Hence, wait another rcu grace period for the storage to be freed.
-	 */
-	synchronize_rcu();
-
-	kvfree(smap->buckets);
-	kfree(smap);
-}
-
 static void sk_storage_map_free(struct bpf_map *map)
 {
 	struct bpf_local_storage_map *smap;
@@ -684,78 +103,6 @@ static void sk_storage_map_free(struct bpf_map *map)
 	bpf_local_storage_map_free(smap);
 }
 
-/* U16_MAX is much more than enough for sk local storage
- * considering a tcp_sock is ~2k.
- */
-#define BPF_LOCAL_STORAGE_MAX_VALUE_SIZE				\
-	min_t(u32,							\
-	      (KMALLOC_MAX_SIZE - MAX_BPF_STACK -			\
-	       sizeof(struct bpf_local_storage_elem)),			\
-	      (U16_MAX - sizeof(struct bpf_local_storage_elem)))
-
-int bpf_local_storage_map_alloc_check(union bpf_attr *attr)
-{
-	if (attr->map_flags & ~BPF_LOCAL_STORAGE_CREATE_FLAG_MASK ||
-	    !(attr->map_flags & BPF_F_NO_PREALLOC) ||
-	    attr->max_entries ||
-	    attr->key_size != sizeof(int) || !attr->value_size ||
-	    /* Enforce BTF for userspace sk dumping */
-	    !attr->btf_key_type_id || !attr->btf_value_type_id)
-		return -EINVAL;
-
-	if (!bpf_capable())
-		return -EPERM;
-
-	if (attr->value_size > BPF_LOCAL_STORAGE_MAX_VALUE_SIZE)
-		return -E2BIG;
-
-	return 0;
-}
-
-struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr)
-{
-	struct bpf_local_storage_map *smap;
-	unsigned int i;
-	u32 nbuckets;
-	u64 cost;
-	int ret;
-
-	smap = kzalloc(sizeof(*smap), GFP_USER | __GFP_NOWARN);
-	if (!smap)
-		return ERR_PTR(-ENOMEM);
-	bpf_map_init_from_attr(&smap->map, attr);
-
-	nbuckets = roundup_pow_of_two(num_possible_cpus());
-	/* Use at least 2 buckets, select_bucket() is undefined behavior with 1 bucket */
-	nbuckets = max_t(u32, 2, nbuckets);
-	smap->bucket_log = ilog2(nbuckets);
-	cost = sizeof(*smap->buckets) * nbuckets + sizeof(*smap);
-
-	ret = bpf_map_charge_init(&smap->map.memory, cost);
-	if (ret < 0) {
-		kfree(smap);
-		return ERR_PTR(ret);
-	}
-
-	smap->buckets = kvcalloc(sizeof(*smap->buckets), nbuckets,
-				 GFP_USER | __GFP_NOWARN);
-	if (!smap->buckets) {
-		bpf_map_charge_finish(&smap->map.memory);
-		kfree(smap);
-		return ERR_PTR(-ENOMEM);
-	}
-
-	for (i = 0; i < nbuckets; i++) {
-		INIT_HLIST_HEAD(&smap->buckets[i].list);
-		raw_spin_lock_init(&smap->buckets[i].lock);
-	}
-
-	smap->elem_size =
-		sizeof(struct bpf_local_storage_elem) + attr->value_size;
-
-	return smap;
-}
-
 static struct bpf_map *sk_storage_map_alloc(union bpf_attr *attr)
 {
 	struct bpf_local_storage_map *smap;
@@ -774,23 +121,6 @@ static int notsupp_get_next_key(struct bpf_map *map, void *key,
 	return -ENOTSUPP;
 }
 
-int bpf_local_storage_map_check_btf(const struct bpf_map *map,
-				    const struct btf *btf,
-				    const struct btf_type *key_type,
-				    const struct btf_type *value_type)
-{
-	u32 int_data;
-
-	if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
-		return -EINVAL;
-
-	int_data = *(u32 *)(key_type + 1);
-	if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data))
-		return -EINVAL;
-
-	return 0;
-}
-
 static void *bpf_fd_sk_storage_lookup_elem(struct bpf_map *map, void *key)
 {
 	struct bpf_local_storage_data *sdata;