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Diffstat (limited to 'Documentation/bpf/map_hash.rst')
| -rw-r--r-- | Documentation/bpf/map_hash.rst | 33 |
1 files changed, 28 insertions, 5 deletions
diff --git a/Documentation/bpf/map_hash.rst b/Documentation/bpf/map_hash.rst index e85120878b27..8669426264c6 100644 --- a/Documentation/bpf/map_hash.rst +++ b/Documentation/bpf/map_hash.rst @@ -34,7 +34,14 @@ the ``BPF_F_NO_COMMON_LRU`` flag when calling ``bpf_map_create``. Usage ===== -.. c:function:: +Kernel BPF +---------- + +bpf_map_update_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags) Hash entries can be added or updated using the ``bpf_map_update_elem()`` @@ -49,14 +56,22 @@ parameter can be used to control the update behaviour: ``bpf_map_update_elem()`` returns 0 on success, or negative error in case of failure. -.. c:function:: +bpf_map_lookup_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + void *bpf_map_lookup_elem(struct bpf_map *map, const void *key) Hash entries can be retrieved using the ``bpf_map_lookup_elem()`` helper. This helper returns a pointer to the value associated with ``key``, or ``NULL`` if no entry was found. -.. c:function:: +bpf_map_delete_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + long bpf_map_delete_elem(struct bpf_map *map, const void *key) Hash entries can be deleted using the ``bpf_map_delete_elem()`` @@ -70,7 +85,11 @@ For ``BPF_MAP_TYPE_PERCPU_HASH`` and ``BPF_MAP_TYPE_LRU_PERCPU_HASH`` the ``bpf_map_update_elem()`` and ``bpf_map_lookup_elem()`` helpers automatically access the hash slot for the current CPU. -.. c:function:: +bpf_map_lookup_percpu_elem() +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + void *bpf_map_lookup_percpu_elem(struct bpf_map *map, const void *key, u32 cpu) The ``bpf_map_lookup_percpu_elem()`` helper can be used to lookup the @@ -89,7 +108,11 @@ See ``tools/testing/selftests/bpf/progs/test_spin_lock.c``. Userspace --------- -.. c:function:: +bpf_map_get_next_key() +~~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + int bpf_map_get_next_key(int fd, const void *cur_key, void *next_key) In userspace, it is possible to iterate through the keys of a hash using |