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author | Mauricio Vasquez B <mauricio.vasquez@polito.it> | 2018-10-18 15:16:25 +0200 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2018-10-19 13:24:31 -0700 |
commit | f1a2e44a3aeccb3ff18d3ccc0b0203e70b95bd92 (patch) | |
tree | 454766bd47fa6030b9e60c96da4536413e661fb7 /kernel/bpf/core.c | |
parent | 2ea864c58f19bf70a0e2415f9f1c53814e07f1b4 (diff) | |
download | linux-stable-f1a2e44a3aeccb3ff18d3ccc0b0203e70b95bd92.tar.gz linux-stable-f1a2e44a3aeccb3ff18d3ccc0b0203e70b95bd92.tar.bz2 linux-stable-f1a2e44a3aeccb3ff18d3ccc0b0203e70b95bd92.zip |
bpf: add queue and stack maps
Queue/stack maps implement a FIFO/LIFO data storage for ebpf programs.
These maps support peek, pop and push operations that are exposed to eBPF
programs through the new bpf_map[peek/pop/push] helpers. Those operations
are exposed to userspace applications through the already existing
syscalls in the following way:
BPF_MAP_LOOKUP_ELEM -> peek
BPF_MAP_LOOKUP_AND_DELETE_ELEM -> pop
BPF_MAP_UPDATE_ELEM -> push
Queue/stack maps are implemented using a buffer, tail and head indexes,
hence BPF_F_NO_PREALLOC is not supported.
As opposite to other maps, queue and stack do not use RCU for protecting
maps values, the bpf_map[peek/pop] have a ARG_PTR_TO_UNINIT_MAP_VALUE
argument that is a pointer to a memory zone where to save the value of a
map. Basically the same as ARG_PTR_TO_UNINIT_MEM, but the size has not
be passed as an extra argument.
Our main motivation for implementing queue/stack maps was to keep track
of a pool of elements, like network ports in a SNAT, however we forsee
other use cases, like for exampling saving last N kernel events in a map
and then analysing from userspace.
Signed-off-by: Mauricio Vasquez B <mauricio.vasquez@polito.it>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/core.c')
-rw-r--r-- | kernel/bpf/core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index defcf4df6d91..7c7eeea8cffc 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1783,6 +1783,9 @@ BPF_CALL_0(bpf_user_rnd_u32) const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; const struct bpf_func_proto bpf_map_update_elem_proto __weak; const struct bpf_func_proto bpf_map_delete_elem_proto __weak; +const struct bpf_func_proto bpf_map_push_elem_proto __weak; +const struct bpf_func_proto bpf_map_pop_elem_proto __weak; +const struct bpf_func_proto bpf_map_peek_elem_proto __weak; const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; |