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docs/bpf: Fix sphinx warnings in BPF map docs

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Fix duplicate C declaration warnings when using sphinx >= 3.1.

Reported-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Akira Yokosawa <akiyks@gmail.com>
Link: https://lore.kernel.org/bpf/ed4dac84-1b12-5c58-e4de-93ab9ac67c09@gmail.com
Link: https://lore.kernel.org/bpf/20221122143933.91321-1-donald.hunter@gmail.com
This commit is contained in:
Donald Hunter 2022-11-22 14:39:33 +00:00 committed by Daniel Borkmann
parent 8e898aaa73
commit 539886a32a
5 changed files with 99 additions and 20 deletions
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20
Documentation/bpf/map_array.rst
View File

@ -32,7 +32,11 @@ Usage
Kernel BPF
----------
.. c:function::
bpf_map_lookup_elem()
~~~~~~~~~~~~~~~~~~~~~
.. code-block:: c
void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
Array elements can be retrieved using the ``bpf_map_lookup_elem()`` helper.
@ -40,7 +44,11 @@ This helper returns a pointer into the array element, so to avoid data races
with userspace reading the value, the user must use primitives like
``__sync_fetch_and_add()`` when updating the value in-place.
.. c:function::
bpf_map_update_elem()
~~~~~~~~~~~~~~~~~~~~~
.. code-block:: c
long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
Array elements can be updated using the ``bpf_map_update_elem()`` helper.
@ -53,7 +61,7 @@ To clear an array element, you may use ``bpf_map_update_elem()`` to insert a
zero value to that index.
Per CPU Array
~~~~~~~~~~~~~
-------------
Values stored in ``BPF_MAP_TYPE_ARRAY`` can be accessed by multiple programs
across different CPUs. To restrict storage to a single CPU, you may use a
@ -63,7 +71,11 @@ When using a ``BPF_MAP_TYPE_PERCPU_ARRAY`` the ``bpf_map_update_elem()`` and
``bpf_map_lookup_elem()`` helpers automatically access the 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 array

33
Documentation/bpf/map_hash.rst
View File

@ -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

24
Documentation/bpf/map_lpm_trie.rst
View File

@ -35,7 +35,11 @@ Usage
Kernel BPF
----------
.. c:function::
bpf_map_lookup_elem()
~~~~~~~~~~~~~~~~~~~~~
.. code-block:: c
void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
The longest prefix entry for a given data value can be found using the
@ -48,7 +52,11 @@ performing longest prefix lookups. For example, when searching for the
longest prefix match for an IPv4 address, ``prefixlen`` should be set to
``32``.
.. c:function::
bpf_map_update_elem()
~~~~~~~~~~~~~~~~~~~~~
.. code-block:: c
long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
Prefix entries can be added or updated using the ``bpf_map_update_elem()``
@ -61,7 +69,11 @@ case of failure.
The flags parameter must be one of BPF_ANY, BPF_NOEXIST or BPF_EXIST,
but the value is ignored, giving BPF_ANY semantics.
.. c:function::
bpf_map_delete_elem()
~~~~~~~~~~~~~~~~~~~~~
.. code-block:: c
long bpf_map_delete_elem(struct bpf_map *map, const void *key)
Prefix entries can be deleted using the ``bpf_map_delete_elem()``
@ -74,7 +86,11 @@ Userspace
Access from userspace uses libbpf APIs with the same names as above, with
the map identified by ``fd``.
.. 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)
A userspace program can iterate through the entries in an LPM trie using

6
Documentation/bpf/map_of_maps.rst
View File

@ -45,7 +45,11 @@ Usage
Kernel BPF Helper
-----------------
.. c:function::
bpf_map_lookup_elem()
~~~~~~~~~~~~~~~~~~~~~
.. code-block:: c
void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
Inner maps can be retrieved using the ``bpf_map_lookup_elem()`` helper. This

36
Documentation/bpf/map_queue_stack.rst
View File

@ -28,7 +28,11 @@ Usage
Kernel BPF
----------
.. c:function::
bpf_map_push_elem()
~~~~~~~~~~~~~~~~~~~
.. code-block:: c
long bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
An element ``value`` can be added to a queue or stack using the
@ -38,14 +42,22 @@ when the queue or stack is full, the oldest element will be removed to
make room for ``value`` to be added. Returns ``0`` on success, or
negative error in case of failure.
.. c:function::
bpf_map_peek_elem()
~~~~~~~~~~~~~~~~~~~
.. code-block:: c
long bpf_map_peek_elem(struct bpf_map *map, void *value)
This helper fetches an element ``value`` from a queue or stack without
removing it. Returns ``0`` on success, or negative error in case of
failure.
.. c:function::
bpf_map_pop_elem()
~~~~~~~~~~~~~~~~~~
.. code-block:: c
long bpf_map_pop_elem(struct bpf_map *map, void *value)
This helper removes an element into ``value`` from a queue or
@ -55,7 +67,11 @@ stack. Returns ``0`` on success, or negative error in case of failure.
Userspace
---------
.. c:function::
bpf_map_update_elem()
~~~~~~~~~~~~~~~~~~~~~
.. code-block:: c
int bpf_map_update_elem (int fd, const void *key, const void *value, __u64 flags)
A userspace program can push ``value`` onto a queue or stack using libbpf's
@ -64,7 +80,11 @@ A userspace program can push ``value`` onto a queue or stack using libbpf's
same semantics as the ``bpf_map_push_elem`` kernel helper. Returns ``0`` on
success, or negative error in case of failure.
.. c:function::
bpf_map_lookup_elem()
~~~~~~~~~~~~~~~~~~~~~
.. code-block:: c
int bpf_map_lookup_elem (int fd, const void *key, void *value)
A userspace program can peek at the ``value`` at the head of a queue or stack
@ -72,7 +92,11 @@ using the libbpf ``bpf_map_lookup_elem`` function. The ``key`` parameter must be
set to ``NULL``. Returns ``0`` on success, or negative error in case of
failure.
.. c:function::
bpf_map_lookup_and_delete_elem()
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. code-block:: c
int bpf_map_lookup_and_delete_elem (int fd, const void *key, void *value)
A userspace program can pop a ``value`` from the head of a queue or stack using