From: Yonghong Song <yhs@fb.com>
To: <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Cong Wang <xiyou.wangcong@gmail.com>,
Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>
Subject: [PATCH bpf-next v2 00/11] bpf: add bpf_for_each_map_elem() helper
Date: Wed, 17 Feb 2021 10:18:03 -0800 [thread overview]
Message-ID: <20210217181803.3189437-1-yhs@fb.com> (raw)
This patch set introduced bpf_for_each_map_elem() helper.
The helper permits bpf program iterates through all elements
for a particular map.
The work originally inspired by an internal discussion where
firewall rules are kept in a map and bpf prog wants to
check packet 5 tuples against all rules in the map.
A bounded loop can be used but it has a few drawbacks.
As the loop iteration goes up, verification time goes up too.
For really large maps, verification may fail.
A helper which abstracts out the loop itself will not have
verification time issue.
A recent discussion in [1] involves to iterate all hash map
elements in bpf program. Currently iterating all hashmap elements
in bpf program is not easy if key space is really big.
Having a helper to abstract out the loop itself is even more
meaningful.
The proposed helper signature looks like:
long bpf_for_each_map_elem(map, callback_fn, callback_ctx, flags)
where callback_fn is a static function and callback_ctx is
a piece of data allocated on the caller stack which can be
accessed by the callback_fn. The callback_fn signature might be
different for different maps. For example, for hash/array maps,
the signature is
long callback_fn(map, key, val, callback_ctx)
In the rest of series, Patches 1/2/3 did some refactoring. Patch 4
implemented core kernel support for the helper. Patches 5 and 6
added hashmap and arraymap support. Patches 7/8 added libbpf
support. Patch 9 added bpftool support. Patches 10 and 11 added
selftests for hashmap and arraymap.
[1]: https://lore.kernel.org/bpf/20210122205415.113822-1-xiyou.wangcong@gmail.com/
Yonghong Song (11):
bpf: factor out visit_func_call_insn() in check_cfg()
bpf: factor out verbose_invalid_scalar()
bpf: refactor check_func_call() to allow callback function
bpf: add bpf_for_each_map_elem() helper
bpf: add hashtab support for bpf_for_each_map_elem() helper
bpf: add arraymap support for bpf_for_each_map_elem() helper
libbpf: move function is_ldimm64() earlier in libbpf.c
libbpf: support local function pointer relocation
bpftool: print local function pointer properly
selftests/bpf: add hashmap test for bpf_for_each_map_elem() helper
selftests/bpf: add arraymap test for bpf_for_each_map_elem() helper
include/linux/bpf.h | 17 +
include/linux/bpf_verifier.h | 3 +
include/uapi/linux/bpf.h | 29 +-
kernel/bpf/arraymap.c | 39 ++
kernel/bpf/bpf_iter.c | 16 +
kernel/bpf/hashtab.c | 63 ++++
kernel/bpf/helpers.c | 2 +
kernel/bpf/verifier.c | 346 +++++++++++++++---
kernel/trace/bpf_trace.c | 2 +
tools/bpf/bpftool/xlated_dumper.c | 3 +
tools/include/uapi/linux/bpf.h | 29 +-
tools/lib/bpf/libbpf.c | 52 ++-
.../selftests/bpf/prog_tests/for_each.c | 132 +++++++
.../bpf/progs/for_each_array_map_elem.c | 61 +++
.../bpf/progs/for_each_hash_map_elem.c | 95 +++++
15 files changed, 829 insertions(+), 60 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/for_each.c
create mode 100644 tools/testing/selftests/bpf/progs/for_each_array_map_elem.c
create mode 100644 tools/testing/selftests/bpf/progs/for_each_hash_map_elem.c
--
2.24.1
next reply other threads:[~2021-02-17 18:19 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-17 18:18 Yonghong Song [this message]
2021-02-17 18:18 ` [PATCH bpf-next v2 01/11] bpf: factor out visit_func_call_insn() in check_cfg() Yonghong Song
2021-02-17 18:18 ` [PATCH bpf-next v2 02/11] bpf: factor out verbose_invalid_scalar() Yonghong Song
2021-02-17 18:18 ` [PATCH bpf-next v2 03/11] bpf: refactor check_func_call() to allow callback function Yonghong Song
2021-02-17 18:18 ` [PATCH bpf-next v2 04/11] bpf: add bpf_for_each_map_elem() helper Yonghong Song
2021-02-22 20:59 ` Alexei Starovoitov
2021-02-23 18:39 ` Yonghong Song
2021-02-23 18:46 ` Alexei Starovoitov
2021-02-23 19:37 ` Yonghong Song
2021-02-17 18:18 ` [PATCH bpf-next v2 05/11] bpf: add hashtab support for " Yonghong Song
2021-02-22 22:56 ` Alexei Starovoitov
2021-02-23 18:41 ` Yonghong Song
2021-02-17 18:18 ` [PATCH bpf-next v2 06/11] bpf: add arraymap " Yonghong Song
2021-02-17 18:18 ` [PATCH bpf-next v2 07/11] libbpf: move function is_ldimm64() earlier in libbpf.c Yonghong Song
2021-02-23 8:06 ` Andrii Nakryiko
2021-02-17 18:18 ` [PATCH bpf-next v2 08/11] libbpf: support local function pointer relocation Yonghong Song
2021-02-23 8:03 ` Andrii Nakryiko
2021-02-23 18:55 ` Yonghong Song
2021-02-23 19:07 ` Alexei Starovoitov
2021-02-23 19:21 ` Andrii Nakryiko
2021-02-23 19:19 ` Andrii Nakryiko
2021-02-23 19:47 ` Yonghong Song
2021-02-23 21:24 ` Andrii Nakryiko
2021-02-17 18:18 ` [PATCH bpf-next v2 09/11] bpftool: print local function pointer properly Yonghong Song
2021-02-23 8:06 ` Andrii Nakryiko
2021-02-23 19:00 ` Yonghong Song
2021-02-17 18:18 ` [PATCH bpf-next v2 10/11] selftests/bpf: add hashmap test for bpf_for_each_map_elem() helper Yonghong Song
2021-02-17 18:18 ` [PATCH bpf-next v2 11/11] selftests/bpf: add arraymap " Yonghong Song
2021-02-17 18:29 ` [PATCH bpf-next v2 00/11] bpf: add " Yonghong Song
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