Move the general maps documentation into the maps.rst file from the
overall networking filter documentation and add a link instead.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
Documentation/bpf/maps.rst | 43 ++++++++++++++++++++++++++
Documentation/networking/filter.rst | 47 ++---------------------------
2 files changed, 46 insertions(+), 44 deletions(-)
diff --git a/Documentation/bpf/maps.rst b/Documentation/bpf/maps.rst
index 2084b0e7cde88..f41619e312ace 100644
--- a/Documentation/bpf/maps.rst
+++ b/Documentation/bpf/maps.rst
@@ -1,4 +1,47 @@
+
+=========
+eBPF maps
=========
+
+'maps' is a generic storage of different types for sharing data between kernel
+and userspace.
+
+The maps are accessed from user space via BPF syscall, which has commands:
+
+- create a map with given type and attributes
+ ``map_fd = bpf(BPF_MAP_CREATE, union bpf_attr *attr, u32 size)``
+ using attr->map_type, attr->key_size, attr->value_size, attr->max_entries
+ returns process-local file descriptor or negative error
+
+- lookup key in a given map
+ ``err = bpf(BPF_MAP_LOOKUP_ELEM, union bpf_attr *attr, u32 size)``
+ using attr->map_fd, attr->key, attr->value
+ returns zero and stores found elem into value or negative error
+
+- create or update key/value pair in a given map
+ ``err = bpf(BPF_MAP_UPDATE_ELEM, union bpf_attr *attr, u32 size)``
+ using attr->map_fd, attr->key, attr->value
+ returns zero or negative error
+
+- find and delete element by key in a given map
+ ``err = bpf(BPF_MAP_DELETE_ELEM, union bpf_attr *attr, u32 size)``
+ using attr->map_fd, attr->key
+
+- to delete map: close(fd)
+ Exiting process will delete maps automatically
+
+userspace programs use this syscall to create/access maps that eBPF programs
+are concurrently updating.
+
+maps can have different types: hash, array, bloom filter, radix-tree, etc.
+
+The map is defined by:
+
+ - type
+ - max number of elements
+ - key size in bytes
+ - value size in bytes
+
Map Types
=========
diff --git a/Documentation/networking/filter.rst b/Documentation/networking/filter.rst
index 83ffcaa5b91aa..43ef05b91f986 100644
--- a/Documentation/networking/filter.rst
+++ b/Documentation/networking/filter.rst
@@ -1232,9 +1232,9 @@ pointer type. The types of pointers describe their base, as follows:
Pointer to the value stored in a map element.
PTR_TO_MAP_VALUE_OR_NULL
Either a pointer to a map value, or NULL; map accesses
- (see section 'eBPF maps', below) return this type,
- which becomes a PTR_TO_MAP_VALUE when checked != NULL.
- Arithmetic on these pointers is forbidden.
+ (see maps.rst) return this type, which becomes a
+ a PTR_TO_MAP_VALUE when checked != NULL. Arithmetic on
+ these pointers is forbidden.
PTR_TO_STACK
Frame pointer.
PTR_TO_PACKET
@@ -1402,47 +1402,6 @@ using normal C code as::
which makes such programs easier to write comparing to LD_ABS insn
and significantly faster.
-eBPF maps
----------
-'maps' is a generic storage of different types for sharing data between kernel
-and userspace.
-
-The maps are accessed from user space via BPF syscall, which has commands:
-
-- create a map with given type and attributes
- ``map_fd = bpf(BPF_MAP_CREATE, union bpf_attr *attr, u32 size)``
- using attr->map_type, attr->key_size, attr->value_size, attr->max_entries
- returns process-local file descriptor or negative error
-
-- lookup key in a given map
- ``err = bpf(BPF_MAP_LOOKUP_ELEM, union bpf_attr *attr, u32 size)``
- using attr->map_fd, attr->key, attr->value
- returns zero and stores found elem into value or negative error
-
-- create or update key/value pair in a given map
- ``err = bpf(BPF_MAP_UPDATE_ELEM, union bpf_attr *attr, u32 size)``
- using attr->map_fd, attr->key, attr->value
- returns zero or negative error
-
-- find and delete element by key in a given map
- ``err = bpf(BPF_MAP_DELETE_ELEM, union bpf_attr *attr, u32 size)``
- using attr->map_fd, attr->key
-
-- to delete map: close(fd)
- Exiting process will delete maps automatically
-
-userspace programs use this syscall to create/access maps that eBPF programs
-are concurrently updating.
-
-maps can have different types: hash, array, bloom filter, radix-tree, etc.
-
-The map is defined by:
-
- - type
- - max number of elements
- - key size in bytes
- - value size in bytes
-
Pruning
-------
The verifier does not actually walk all possible paths through the program. For
--
2.30.2
