[PATCH bpf-next v5 3/7] bpf: Generalize bpf_sk_storage
From: KP Singh
Date: Wed Jul 22 2020 - 13:14:53 EST
From: KP Singh <kpsingh@xxxxxxxxxx>
Refactor the functionality in bpf_sk_storage.c so that concept of
storage linked to kernel objects can be extended to other objects like
inode, task_struct etc.
Each new local storage will still be a separate map and provide its own
set of helpers. This allows for future object specific extensions and
still share a lot of the underlying implementation.
Signed-off-by: KP Singh <kpsingh@xxxxxxxxxx>
---
include/linux/bpf.h | 13 ++
include/net/bpf_sk_storage.h | 55 +++++
include/uapi/linux/bpf.h | 8 +-
net/core/bpf_sk_storage.c | 387 ++++++++++++++++++++-------------
tools/include/uapi/linux/bpf.h | 8 +-
5 files changed, 320 insertions(+), 151 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index bae557ff2da8..9b83665b56e4 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -33,6 +33,9 @@ struct btf;
struct btf_type;
struct exception_table_entry;
struct seq_operations;
+struct bpf_local_storage;
+struct bpf_local_storage_map;
+struct bpf_local_storage_elem;
extern struct idr btf_idr;
extern spinlock_t btf_idr_lock;
@@ -93,6 +96,16 @@ struct bpf_map_ops {
__poll_t (*map_poll)(struct bpf_map *map, struct file *filp,
struct poll_table_struct *pts);
+ /* Functions called by bpf_local_storage maps */
+ bool (*map_local_storage_unlink)(struct bpf_local_storage *local_storage,
+ struct bpf_local_storage_elem *selem,
+ bool uncharge_omem);
+ struct bpf_local_storage_elem *(*map_selem_alloc)(
+ struct bpf_local_storage_map *smap, void *owner, void *value,
+ bool charge_omem);
+ struct bpf_local_storage_data *(*map_local_storage_update)(
+ void *owner, struct bpf_map *map, void *value, u64 flags);
+
/* BTF name and id of struct allocated by map_alloc */
const char * const map_btf_name;
int *map_btf_id;
diff --git a/include/net/bpf_sk_storage.h b/include/net/bpf_sk_storage.h
index 950c5aaba15e..e3185cfb91da 100644
--- a/include/net/bpf_sk_storage.h
+++ b/include/net/bpf_sk_storage.h
@@ -3,8 +3,15 @@
#ifndef _BPF_SK_STORAGE_H
#define _BPF_SK_STORAGE_H
+#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 <net/sock.h>
+#include <uapi/linux/sock_diag.h>
+#include <uapi/linux/btf.h>
struct sock;
@@ -34,6 +41,54 @@ 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(struct bpf_local_storage *local_storage,
+ struct bpf_local_storage_elem *selem);
+
+bool bpf_selem_unlink_storage(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 *value);
+
+struct bpf_local_storage *
+bpf_local_storage_alloc(struct bpf_local_storage_map *smap);
+
+int bpf_local_storage_publish(struct bpf_local_storage_elem *first_selem,
+ struct bpf_local_storage **addr,
+ struct bpf_local_storage *curr);
+
+int bpf_local_storage_check_update_flags(struct bpf_map *map, u64 map_flags);
+
+struct bpf_local_storage_data *
+bpf_local_storage_update(void *owner, struct bpf_map *map,
+ struct bpf_local_storage *local_storage, 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/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 54d0c886e3ba..b9d2e4792d08 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3630,9 +3630,13 @@ enum {
BPF_F_SYSCTL_BASE_NAME = (1ULL << 0),
};
-/* BPF_FUNC_sk_storage_get flags */
+/* BPF_FUNC_<local>_storage_get flags */
enum {
- BPF_SK_STORAGE_GET_F_CREATE = (1ULL << 0),
+ BPF_LOCAL_STORAGE_GET_F_CREATE = (1ULL << 0),
+ /* BPF_SK_STORAGE_GET_F_CREATE is only kept for backward compatibility
+ * and BPF_LOCAL_STORAGE_GET_F_CREATE must be used instead.
+ */
+ BPF_SK_STORAGE_GET_F_CREATE = BPF_LOCAL_STORAGE_GET_F_CREATE,
};
/* BPF_FUNC_read_branch_records flags. */
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index aa3e3a47acb5..f6bb02f076ad 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -83,7 +83,7 @@ struct bpf_local_storage_elem {
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 */
- struct sock *owner; /* The object that owns the the above "list" of
+ void *owner; /* The object that owns the the above "list" of
* bpf_local_storage_elem.
*/
struct rcu_head rcu;
@@ -119,15 +119,11 @@ static bool selem_linked_to_map(const struct bpf_local_storage_elem *selem)
return !hlist_unhashed(&selem->map_node);
}
-static struct bpf_local_storage_elem *
-bpf_selem_alloc(struct bpf_local_storage_map *smap, struct sock *sk,
- void *value, bool charge_omem)
+struct bpf_local_storage_elem *
+bpf_selem_alloc(struct bpf_local_storage_map *smap, void *value)
{
struct bpf_local_storage_elem *selem;
- if (charge_omem && omem_charge(sk, smap->elem_size))
- return NULL;
-
selem = kzalloc(smap->elem_size, GFP_ATOMIC | __GFP_NOWARN);
if (selem) {
if (value)
@@ -135,6 +131,23 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, struct sock *sk,
return selem;
}
+ return NULL;
+}
+
+static struct bpf_local_storage_elem *
+sk_selem_alloc(struct bpf_local_storage_map *smap, void *owner, void *value,
+ bool charge_omem)
+{
+ struct bpf_local_storage_elem *selem;
+ struct sock *sk = owner;
+
+ if (charge_omem && omem_charge(sk, smap->elem_size))
+ return NULL;
+
+ selem = bpf_selem_alloc(smap, value);
+ if (selem)
+ return selem;
+
if (charge_omem)
atomic_sub(smap->elem_size, &sk->sk_omem_alloc);
@@ -145,51 +158,65 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, struct sock *sk,
* The caller must ensure selem->smap is still valid to be
* dereferenced for its smap->elem_size and smap->cache_idx.
*/
-static bool bpf_selem_unlink_storage(struct bpf_local_storage *local_storage,
- struct bpf_local_storage_elem *selem,
- bool uncharge_omem)
+bool bpf_selem_unlink_storage(struct bpf_local_storage *local_storage,
+ struct bpf_local_storage_elem *selem,
+ bool uncharge_omem)
{
struct bpf_local_storage_map *smap;
bool free_local_storage;
- struct sock *sk;
smap = rcu_dereference(SDATA(selem)->smap);
- sk = local_storage->owner;
+ /* 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.
+ */
+ free_local_storage = smap->map.ops->map_local_storage_unlink(
+ local_storage, selem, uncharge_omem);
+ 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 bool unlink_sk_storage(struct bpf_local_storage *local_storage,
+ struct bpf_local_storage_elem *selem,
+ bool uncharge_omem)
+{
+ struct bpf_local_storage_map *smap;
+ struct sock *sk = local_storage->owner;
+ bool free_local_storage;
+
+ smap = rcu_dereference(SDATA(selem)->smap);
/* All uncharging on sk->sk_omem_alloc must be done first.
* sk may be freed once the last selem is unlinked from local_storage.
*/
- if (uncharge_omem)
- atomic_sub(smap->elem_size, &sk->sk_omem_alloc);
free_local_storage = hlist_is_singular_node(&selem->snode,
&local_storage->list);
+
+ if (uncharge_omem)
+ atomic_sub(smap->elem_size, &sk->sk_omem_alloc);
+
if (free_local_storage) {
- atomic_sub(sizeof(struct bpf_local_storage), &sk->sk_omem_alloc);
- local_storage->owner = NULL;
+ atomic_sub(sizeof(struct bpf_local_storage),
+ &sk->sk_omem_alloc);
+
/* After this RCU_INIT, sk may be freed and cannot be used */
RCU_INIT_POINTER(sk->sk_bpf_storage, 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.
- */
+ local_storage->owner = NULL;
}
- 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;
}
@@ -214,14 +241,14 @@ static void __bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem)
kfree_rcu(local_storage, rcu);
}
-static void bpf_selem_link_storage(struct bpf_local_storage *local_storage,
- struct bpf_local_storage_elem *selem)
+void bpf_selem_link_storage(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);
}
-static void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem)
+void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem)
{
struct bpf_local_storage_map *smap;
struct bpf_local_storage_map_bucket *b;
@@ -238,8 +265,8 @@ static void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem)
raw_spin_unlock_bh(&b->lock);
}
-static void bpf_selem_link_map(struct bpf_local_storage_map *smap,
- struct bpf_local_storage_elem *selem)
+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);
@@ -249,7 +276,7 @@ static void bpf_selem_link_map(struct bpf_local_storage_map *smap,
raw_spin_unlock_bh(&b->lock);
}
-static void bpf_selem_unlink(struct bpf_local_storage_elem *selem)
+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
@@ -259,7 +286,7 @@ static void bpf_selem_unlink(struct bpf_local_storage_elem *selem)
__bpf_selem_unlink_storage(selem);
}
-static struct bpf_local_storage_data *
+struct bpf_local_storage_data *
bpf_local_storage_lookup(struct bpf_local_storage *local_storage,
struct bpf_local_storage_map *smap,
bool cacheit_lockit)
@@ -325,59 +352,53 @@ static int check_flags(const struct bpf_local_storage_data *old_sdata,
return 0;
}
-static int sk_storage_alloc(struct sock *sk,
+struct bpf_local_storage *
+bpf_local_storage_alloc(struct bpf_local_storage_map *smap)
+{
+ struct bpf_local_storage *storage;
+
+ storage = kzalloc(sizeof(*storage), GFP_ATOMIC | __GFP_NOWARN);
+ if (!storage)
+ return NULL;
+
+ INIT_HLIST_HEAD(&storage->list);
+ raw_spin_lock_init(&storage->lock);
+ return storage;
+}
+
+static int sk_storage_alloc(void *owner,
struct bpf_local_storage_map *smap,
struct bpf_local_storage_elem *first_selem)
{
- struct bpf_local_storage *prev_sk_storage, *sk_storage;
+ struct bpf_local_storage *curr;
+ struct sock *sk = owner;
int err;
- err = omem_charge(sk, sizeof(*sk_storage));
+ err = omem_charge(sk, sizeof(*curr));
if (err)
return err;
- sk_storage = kzalloc(sizeof(*sk_storage), GFP_ATOMIC | __GFP_NOWARN);
- if (!sk_storage) {
+ curr = bpf_local_storage_alloc(smap);
+ if (!curr) {
err = -ENOMEM;
goto uncharge;
}
- INIT_HLIST_HEAD(&sk_storage->list);
- raw_spin_lock_init(&sk_storage->lock);
- sk_storage->owner = sk;
- bpf_selem_link_storage(sk_storage, first_selem);
+ curr->owner = sk;
+
+ bpf_selem_link_storage(curr, first_selem);
bpf_selem_link_map(smap, first_selem);
- /* Publish sk_storage to sk. sk->sk_lock cannot be acquired.
- * Hence, atomic ops is used to set sk->sk_bpf_storage
- * from NULL to the newly allocated sk_storage ptr.
- *
- * From now on, the sk->sk_bpf_storage pointer is protected
- * by the sk_storage->lock. Hence, when freeing
- * the sk->sk_bpf_storage, the sk_storage->lock must
- * be held before setting sk->sk_bpf_storage to NULL.
- */
- prev_sk_storage = cmpxchg((struct bpf_local_storage **)&sk->sk_bpf_storage,
- NULL, sk_storage);
- if (unlikely(prev_sk_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_sk_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().
- */
- }
+ err = bpf_local_storage_publish(first_selem,
+ (struct bpf_local_storage **)&sk->sk_bpf_storage, curr);
+ if (err)
+ goto uncharge;
return 0;
uncharge:
- kfree(sk_storage);
- atomic_sub(sizeof(*sk_storage), &sk->sk_omem_alloc);
+ kfree(curr);
+ atomic_sub(sizeof(*curr), &sk->sk_omem_alloc);
return err;
}
@@ -386,54 +407,28 @@ static int sk_storage_alloc(struct sock *sk,
* Otherwise, it will become a leak (and other memory issues
* during map destruction).
*/
-static struct bpf_local_storage_data *
-bpf_local_storage_update(struct sock *sk, struct bpf_map *map, void *value,
+struct bpf_local_storage_data *
+bpf_local_storage_update(void *owner, struct bpf_map *map,
+ struct bpf_local_storage *local_storage, 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;
struct bpf_local_storage_map *smap;
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(map)))
- return ERR_PTR(-EINVAL);
-
smap = (struct bpf_local_storage_map *)map;
- local_storage = rcu_dereference(sk->sk_bpf_storage);
- if (!local_storage || hlist_empty(&local_storage->list)) {
- /* Very first elem for this object */
- err = check_flags(NULL, map_flags);
- if (err)
- return ERR_PTR(err);
-
- selem = bpf_selem_alloc(smap, sk, value, true);
- if (!selem)
- return ERR_PTR(-ENOMEM);
-
- err = sk_storage_alloc(sk, smap, selem);
- if (err) {
- kfree(selem);
- atomic_sub(smap->elem_size, &sk->sk_omem_alloc);
- 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);
+ 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(map, old_sdata->data,
value, false);
@@ -471,10 +466,9 @@ bpf_local_storage_update(struct sock *sk, struct bpf_map *map, void *value,
* 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().
+ * old_sdata will not be uncharged later during bpf_selem_unlink().
*/
- selem = bpf_selem_alloc(smap, sk, value, !old_sdata);
+ selem = map->ops->map_selem_alloc(smap, owner, value, !old_sdata);
if (!selem) {
err = -ENOMEM;
goto unlock_err;
@@ -501,6 +495,87 @@ bpf_local_storage_update(struct sock *sk, struct bpf_map *map, void *value,
return ERR_PTR(err);
}
+int bpf_local_storage_check_update_flags(struct bpf_map *map, u64 map_flags)
+{
+ /* 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(map)))
+ return -EINVAL;
+
+ return 0;
+}
+
+/* Publish local_storage to the address. This is used because we are already
+ * in a region where we cannot grab a lock on the object owning the storage (
+ * (e.g sk->sk_lock). Hence, atomic ops is used.
+ *
+ * From now on, the addr pointer is protected
+ * by the local_storage->lock. Hence, upon freeing,
+ * the local_storage->lock must be held before unlinking the storage from the
+ * owner.
+ */
+int bpf_local_storage_publish(struct bpf_local_storage_elem *first_selem,
+ struct bpf_local_storage **addr,
+ struct bpf_local_storage *curr)
+{
+ struct bpf_local_storage *prev;
+
+ prev = cmpxchg(addr, NULL, curr);
+ if (unlikely(prev)) {
+ /* 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().
+ */
+ bpf_selem_unlink_map(first_selem);
+ return -EAGAIN;
+ }
+
+ return 0;
+}
+
+static struct bpf_local_storage_data *
+sk_storage_update(void *owner, struct bpf_map *map, 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;
+ struct bpf_local_storage_map *smap;
+ struct sock *sk;
+ int err;
+
+ err = bpf_local_storage_check_update_flags(map, map_flags);
+ if (err)
+ return ERR_PTR(err);
+
+ sk = owner;
+ local_storage = rcu_dereference(sk->sk_bpf_storage);
+ smap = (struct bpf_local_storage_map *)map;
+
+ if (!local_storage || hlist_empty(&local_storage->list)) {
+ /* Very first elem */
+ selem = map->ops->map_selem_alloc(smap, owner, value, !old_sdata);
+ if (!selem)
+ return ERR_PTR(-ENOMEM);
+
+ err = sk_storage_alloc(owner, smap, selem);
+ if (err) {
+ kfree(selem);
+ atomic_sub(smap->elem_size, &sk->sk_omem_alloc);
+ return ERR_PTR(err);
+ }
+
+ return SDATA(selem);
+ }
+
+ return bpf_local_storage_update(owner, map, local_storage, value,
+ map_flags);
+}
+
static int sk_storage_delete(struct sock *sk, struct bpf_map *map)
{
struct bpf_local_storage_data *sdata;
@@ -566,7 +641,7 @@ void bpf_sk_storage_free(struct sock *sk)
* Thus, no elem can be added-to or deleted-from the
* sk_storage->list by the bpf_prog or by the bpf-map's syscall.
*
- * It is racing with bpf_sk_storage_map_free() alone
+ * It is racing with bpf_local_storage_map_free() alone
* when unlinking elem from the sk_storage->list and
* the map's bucket->list.
*/
@@ -586,17 +661,12 @@ void bpf_sk_storage_free(struct sock *sk)
kfree_rcu(sk_storage, rcu);
}
-static void bpf_local_storage_map_free(struct bpf_map *map)
+void bpf_local_storage_map_free(struct bpf_local_storage_map *smap)
{
struct bpf_local_storage_elem *selem;
- struct bpf_local_storage_map *smap;
struct bpf_local_storage_map_bucket *b;
unsigned int i;
- smap = (struct bpf_local_storage_map *)map;
-
- bpf_local_storage_cache_idx_free(&sk_cache, smap->cache_idx);
-
/* 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
@@ -606,42 +676,51 @@ static void bpf_local_storage_map_free(struct bpf_map *map)
/* bpf prog and the userspace can no longer access this map
* now. No new selem (of this map) can be added
- * to the sk->sk_bpf_storage or to the map bucket's list.
+ * to the bpf_local_storage or to the map bucket's list.
*
* The elem of this map can be cleaned up here
- * or
- * by bpf_sk_storage_free() during __sk_destruct().
+ * or by bpf_local_storage_free() during the destruction of the
+ * owner object. eg. __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))) {
+ 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();
}
- /* bpf_sk_storage_free() may still need to access the map.
- * e.g. bpf_sk_storage_free() has unlinked selem from the map
+ /* bpf_local_storage_free() may still need to access the map.
+ * e.g. bpf_local_storage_free() has unlinked selem from the map
* which then made the above while((selem = ...)) loop
* exited immediately.
*
- * However, the bpf_sk_storage_free() still needs to access
+ * However, the bpf_local_storage_free() still needs to access
* the smap->elem_size to do the uncharging in
- * bpf_selem_unlink_storage().
+ * bpf_selem_unlink().
*
* Hence, wait another rcu grace period for the
- * bpf_sk_storage_free() to finish.
+ * bpf_local_storage_free() to finish.
*/
synchronize_rcu();
kvfree(smap->buckets);
- kfree(map);
+ kfree(smap);
+}
+
+static void sk_storage_map_free(struct bpf_map *map)
+{
+ struct bpf_local_storage_map *smap;
+
+ smap = (struct bpf_local_storage_map *)map;
+ bpf_local_storage_cache_idx_free(&sk_cache, smap->cache_idx);
+ bpf_local_storage_map_free(smap);
}
/* U16_MAX is much more than enough for sk local storage
@@ -653,7 +732,7 @@ static void bpf_local_storage_map_free(struct bpf_map *map)
sizeof(struct bpf_local_storage_elem)), \
(U16_MAX - sizeof(struct bpf_local_storage_elem)))
-static int bpf_sk_storage_map_alloc_check(union bpf_attr *attr)
+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) ||
@@ -672,7 +751,7 @@ static int bpf_sk_storage_map_alloc_check(union bpf_attr *attr)
return 0;
}
-static struct bpf_map *bpf_local_storage_map_alloc(union bpf_attr *attr)
+struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr)
{
struct bpf_local_storage_map *smap;
unsigned int i;
@@ -710,9 +789,21 @@ static struct bpf_map *bpf_local_storage_map_alloc(union bpf_attr *attr)
raw_spin_lock_init(&smap->buckets[i].lock);
}
- smap->elem_size = sizeof(struct bpf_local_storage_elem) + attr->value_size;
- smap->cache_idx = bpf_local_storage_cache_idx_get(&sk_cache);
+ 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;
+
+ smap = bpf_local_storage_map_alloc(attr);
+ if (IS_ERR(smap))
+ return ERR_CAST(smap);
+
+ smap->cache_idx = bpf_local_storage_cache_idx_get(&sk_cache);
return &smap->map;
}
@@ -722,10 +813,10 @@ static int notsupp_get_next_key(struct bpf_map *map, void *key,
return -ENOTSUPP;
}
-static int bpf_sk_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)
+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;
@@ -766,8 +857,7 @@ static int bpf_fd_sk_storage_update_elem(struct bpf_map *map, void *key,
fd = *(int *)key;
sock = sockfd_lookup(fd, &err);
if (sock) {
- sdata = bpf_local_storage_update(sock->sk, map, value,
- map_flags);
+ sdata = sk_storage_update(sock->sk, map, value, map_flags);
sockfd_put(sock);
return PTR_ERR_OR_ZERO(sdata);
}
@@ -798,7 +888,7 @@ bpf_sk_storage_clone_elem(struct sock *newsk,
{
struct bpf_local_storage_elem *copy_selem;
- copy_selem = bpf_selem_alloc(smap, newsk, NULL, true);
+ copy_selem = sk_selem_alloc(smap, newsk, NULL, true);
if (!copy_selem)
return NULL;
@@ -900,7 +990,7 @@ BPF_CALL_4(bpf_sk_storage_get, struct bpf_map *, map, struct sock *, sk,
* destruction).
*/
refcount_inc_not_zero(&sk->sk_refcnt)) {
- sdata = bpf_local_storage_update(sk, map, value, BPF_NOEXIST);
+ sdata = sk_storage_update(sk, map, value, BPF_NOEXIST);
/* sk must be a fullsock (guaranteed by verifier),
* so sock_gen_put() is unnecessary.
*/
@@ -927,16 +1017,19 @@ BPF_CALL_2(bpf_sk_storage_delete, struct bpf_map *, map, struct sock *, sk)
static int sk_storage_map_btf_id;
const struct bpf_map_ops sk_storage_map_ops = {
- .map_alloc_check = bpf_sk_storage_map_alloc_check,
- .map_alloc = bpf_local_storage_map_alloc,
- .map_free = bpf_local_storage_map_free,
+ .map_alloc_check = bpf_local_storage_map_alloc_check,
+ .map_alloc = sk_storage_map_alloc,
+ .map_free = sk_storage_map_free,
.map_get_next_key = notsupp_get_next_key,
.map_lookup_elem = bpf_fd_sk_storage_lookup_elem,
.map_update_elem = bpf_fd_sk_storage_update_elem,
.map_delete_elem = bpf_fd_sk_storage_delete_elem,
- .map_check_btf = bpf_sk_storage_map_check_btf,
+ .map_check_btf = bpf_local_storage_map_check_btf,
.map_btf_name = "bpf_local_storage_map",
.map_btf_id = &sk_storage_map_btf_id,
+ .map_selem_alloc = sk_selem_alloc,
+ .map_local_storage_update = sk_storage_update,
+ .map_local_storage_unlink = unlink_sk_storage,
};
const struct bpf_func_proto bpf_sk_storage_get_proto = {
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 54d0c886e3ba..b9d2e4792d08 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3630,9 +3630,13 @@ enum {
BPF_F_SYSCTL_BASE_NAME = (1ULL << 0),
};
-/* BPF_FUNC_sk_storage_get flags */
+/* BPF_FUNC_<local>_storage_get flags */
enum {
- BPF_SK_STORAGE_GET_F_CREATE = (1ULL << 0),
+ BPF_LOCAL_STORAGE_GET_F_CREATE = (1ULL << 0),
+ /* BPF_SK_STORAGE_GET_F_CREATE is only kept for backward compatibility
+ * and BPF_LOCAL_STORAGE_GET_F_CREATE must be used instead.
+ */
+ BPF_SK_STORAGE_GET_F_CREATE = BPF_LOCAL_STORAGE_GET_F_CREATE,
};
/* BPF_FUNC_read_branch_records flags. */
--
2.28.0.rc0.105.gf9edc3c819-goog