One of our internal services started to use sk_msg program and currently it used existing prog attach/detach2 as demonstrated in selftests. But attach/detach of all other bpf programs are based on bpf_link. Consistent attach/detach APIs for all programs will make things easy to undersand and less error prone. So this patch added bpf_link support for BPF_PROG_TYPE_SK_MSG. Based on comments from previous RFC patch, I added BPF_PROG_TYPE_SK_SKB support as well as both program types have similar treatment w.r.t. bpf_link handling. For the patch series, patch 1 added kernel support. Patch 2 added libbpf support. Patch 3 added bpftool support and patches 4/5 added some new tests. Changelogs: v4 -> v5: - increase scope of mutex protection in link_release. - remove previous-leftover entry in libbpf.map. - make some code changes for better understanding. v3 -> v4: - use a single mutex lock to protect both attach/detach/update and release/fill_info/show_fdinfo. - simplify code for sock_map_link_lookup(). - fix a few bugs. - add more tests. v2 -> v3: - consolidate link types of sk_msg and sk_skb to a single link type BPF_PROG_TYPE_SOCKMAP. - fix bpf_link lifecycle issue. in v2, after bpf_link is attached, a subsequent prog_attach could change that bpf_link. this patch makes bpf_link having correct behavior such that it won't go away facing other prog/link attach for the same map and the same attach type. Yonghong Song (5): bpf: Add bpf_link support for sk_msg and sk_skb progs libbpf: Add bpf_link support for BPF_PROG_TYPE_SOCKMAP bpftool: Add link dump support for BPF_LINK_TYPE_SOCKMAP selftests/bpf: Refactor out helper functions for a few tests selftests/bpf: Add some tests with new bpf_program__attach_sockmap() APIs include/linux/bpf.h | 6 + include/linux/skmsg.h | 4 + include/uapi/linux/bpf.h | 5 + kernel/bpf/syscall.c | 4 + net/core/sock_map.c | 270 ++++++++++++++++-- tools/bpf/bpftool/link.c | 9 + tools/include/uapi/linux/bpf.h | 5 + tools/lib/bpf/libbpf.c | 7 + tools/lib/bpf/libbpf.h | 2 + tools/lib/bpf/libbpf.map | 5 + tools/lib/bpf/libbpf_version.h | 2 +- .../selftests/bpf/prog_tests/sockmap_basic.c | 171 ++++++++++- .../selftests/bpf/prog_tests/sockmap_listen.c | 38 +++ .../bpf/progs/test_skmsg_load_helpers.c | 27 +- .../bpf/progs/test_sockmap_pass_prog.c | 17 +- .../progs/test_sockmap_skb_verdict_attach.c | 2 +- 16 files changed, 537 insertions(+), 37 deletions(-) -- 2.43.0