libbpf: Add "bool skipped" to struct bpf_map

Fix error: "failed to pin map: Bad file descriptor, path:
/sys/fs/bpf/_rodata_str1_1."

In the old kernel, the global data map will not be created, see [0]. So
we should skip the pinning of the global data map to avoid
bpf_object__pin_maps returning error. Therefore, when the map is not
created, we mark “map->skipped" as true and then check during relocation
and during pinning.

Fixes: 16e0c35c6f ("libbpf: Load global data maps lazily on legacy kernels")
Signed-off-by: Shuyi Cheng <chengshuyi@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
This commit is contained in:
Shuyi Cheng 2021-12-10 17:39:57 +08:00 committed by Andrii Nakryiko
parent b69c5c07a6
commit 229fae38d0
1 changed files with 8 additions and 3 deletions

View File

@ -431,6 +431,7 @@ struct bpf_map {
char *pin_path;
bool pinned;
bool reused;
bool skipped;
__u64 map_extra;
};
@ -5087,8 +5088,10 @@ bpf_object__create_maps(struct bpf_object *obj)
* kernels.
*/
if (bpf_map__is_internal(map) &&
!kernel_supports(obj, FEAT_GLOBAL_DATA))
!kernel_supports(obj, FEAT_GLOBAL_DATA)) {
map->skipped = true;
continue;
}
retried = false;
retry:
@ -5717,8 +5720,7 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog)
} else {
const struct bpf_map *map = &obj->maps[relo->map_idx];
if (bpf_map__is_internal(map) &&
!kernel_supports(obj, FEAT_GLOBAL_DATA)) {
if (map->skipped) {
pr_warn("prog '%s': relo #%d: kernel doesn't support global data\n",
prog->name, i);
return -ENOTSUP;
@ -7926,6 +7928,9 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
char *pin_path = NULL;
char buf[PATH_MAX];
if (map->skipped)
continue;
if (path) {
int len;