| Message ID | 20230223011238.12313-6-kuifeng@meta.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | Transit between BPF TCP congestion controls. | expand |
| Context | Check | Description |
|---|---|---|
| bpf/vmtest-bpf-next-PR | fail | merge-conflict |
| netdev/tree_selection | success | Clearly marked for bpf-next, async |
| netdev/apply | fail | Patch does not apply to bpf-next |
| bpf/vmtest-bpf-next-VM_Test-1 | success | Logs for ${{ matrix.test }} on ${{ matrix.arch }} with ${{ matrix.toolchain }} |
| bpf/vmtest-bpf-next-VM_Test-2 | success | Logs for ShellCheck |
| bpf/vmtest-bpf-next-VM_Test-3 | fail | Logs for build for aarch64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-4 | fail | Logs for build for aarch64 with llvm-16 |
| bpf/vmtest-bpf-next-VM_Test-5 | fail | Logs for build for s390x with gcc |
| bpf/vmtest-bpf-next-VM_Test-6 | success | Logs for build for x86_64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-7 | success | Logs for build for x86_64 with llvm-16 |
| bpf/vmtest-bpf-next-VM_Test-8 | success | Logs for llvm-toolchain |
| bpf/vmtest-bpf-next-VM_Test-9 | success | Logs for set-matrix |
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 40f239cd1150..0cb3e5ed4d18 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -11524,6 +11524,42 @@ struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map) return &link->link; } +/* + * Swap the back struct_ops of a link with a new struct_ops map. + */ +int bpf_link__update_map(struct bpf_link *link, const struct bpf_map *map) +{ + struct bpf_link_struct_ops *st_ops_link; + __u32 zero = 0; + int err, fd; + + if (!bpf_map__is_struct_ops(map) || map->fd == -1) + return -EINVAL; + + /* Ensure the type of a link is correct */ + if (link->detach != bpf_link__detach_struct_ops) + return -EINVAL; + + err = bpf_map_update_elem(map->fd, &zero, map->st_ops->kern_vdata, 0); + if (err) { + err = -errno; + free(link); + return err; + } + + fd = bpf_link_update(link->fd, map->fd, NULL); + if (fd < 0) { + err = -errno; + free(link); + return err; + } + + st_ops_link = container_of(link, struct bpf_link_struct_ops, link); + st_ops_link->map_fd = map->fd; + + return 0; +} + typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(struct perf_event_header *hdr, void *private_data); diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 2efd80f6f7b9..5e62878d184c 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -695,6 +695,7 @@ bpf_program__attach_freplace(const struct bpf_program *prog, struct bpf_map; LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map); +LIBBPF_API int bpf_link__update_map(struct bpf_link *link, const struct bpf_map *map); struct bpf_iter_attach_opts { size_t sz; /* size of this struct for forward/backward compatibility */ diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 11c36a3c1a9f..e83571b04c19 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -384,4 +384,6 @@ LIBBPF_1.1.0 { } LIBBPF_1.0.0; LIBBPF_1.2.0 { + global: + bpf_link__update_map; } LIBBPF_1.1.0;
Introduce bpf_link__update_struct_ops(), which will allow you to effortlessly transition the struct_ops map of any given bpf_link into an alternative. Signed-off-by: Kui-Feng Lee <kuifeng@meta.com> --- tools/lib/bpf/libbpf.c | 36 ++++++++++++++++++++++++++++++++++++ tools/lib/bpf/libbpf.h | 1 + tools/lib/bpf/libbpf.map | 2 ++ 3 files changed, 39 insertions(+)