[PATCH iproute2 -next 1/5] {f,m}_bpf: make tail calls working
STALE3962d
REVIEWED: 5 (5M)
From: Daniel Borkmann <daniel@iogearbox.net>
Date: 2015-11-26 12:58:38
Subsystem:
the rest · Maintainer:
Linus Torvalds
Revision v1 of 9 in this series; 1 review trailer.
Revisions (9)
Now that we have the possibility of sharing maps, it's time we get the ELF loader fully working with regards to tail calls. Since program array maps are pinned, we can keep them finally alive. I've noticed two bugs that are being fixed in bpf_fill_prog_arrays() with this patch. Example code comes as follow-up. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> --- tc/tc_bpf.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/tc/tc_bpf.c b/tc/tc_bpf.c
index bc7bc9f..73a0f41 100644
--- a/tc/tc_bpf.c
+++ b/tc/tc_bpf.c@@ -1139,11 +1139,26 @@ static int bpf_fetch_prog_sec(struct bpf_elf_ctx *ctx, const char *section) return ret; } +static int bpf_find_map_by_id(struct bpf_elf_ctx *ctx, uint32_t id) +{ + int i, ret = -1; + + for (i = 0; i < ARRAY_SIZE(ctx->map_fds); i++) { + if (ctx->map_fds[i] && ctx->maps[i].id == id && + ctx->maps[i].type == BPF_MAP_TYPE_PROG_ARRAY) { + ret = i; + break; + } + } + + return ret; +} + static int bpf_fill_prog_arrays(struct bpf_elf_ctx *ctx) { struct bpf_elf_sec_data data; uint32_t map_id, key_id; - int fd, i, ret; + int fd, i, ret, idx; for (i = 1; i < ctx->elf_hdr.e_shnum; i++) { if (ctx->sec_done[i])
@@ -1153,20 +1168,20 @@ static int bpf_fill_prog_arrays(struct bpf_elf_ctx *ctx) if (ret < 0) continue; - ret = sscanf(data.sec_name, "%u/%u", &map_id, &key_id); - if (ret != 2 || map_id >= ARRAY_SIZE(ctx->map_fds) || - !ctx->map_fds[map_id]) + ret = sscanf(data.sec_name, "%i/%i", &map_id, &key_id); + if (ret != 2) continue; - if (ctx->maps[map_id].type != BPF_MAP_TYPE_PROG_ARRAY || - ctx->maps[map_id].max_elem <= key_id) + + idx = bpf_find_map_by_id(ctx, map_id); + if (idx < 0) continue; fd = bpf_fetch_prog_sec(ctx, data.sec_name); if (fd < 0) return -EIO; - ret = bpf_map_update(ctx->map_fds[map_id], &key_id, - &fd, BPF_NOEXIST); + ret = bpf_map_update(ctx->map_fds[idx], &key_id, + &fd, BPF_ANY); if (ret < 0) return -ENOENT;
--
1.9.3