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    Subject[PATCH 5.16 0268/1039] libbpf: Add "bool skipped" to struct bpf_map
    Date
    From: Shuyi Cheng <chengshuyi@linux.alibaba.com>

    [ Upstream commit 229fae38d0fc0d6ff58d57cbeb1432da55e58d4f ]

    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: 16e0c35c6f7a ("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>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    tools/lib/bpf/libbpf.c | 11 ++++++++---
    1 file changed, 8 insertions(+), 3 deletions(-)

    diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
    index 4050a0f8dad66..fd25e30e70cc2 100644
    --- a/tools/lib/bpf/libbpf.c
    +++ b/tools/lib/bpf/libbpf.c
    @@ -400,6 +400,7 @@ struct bpf_map {
    char *pin_path;
    bool pinned;
    bool reused;
    + bool skipped;
    __u64 map_extra;
    };

    @@ -5003,8 +5004,10 @@ 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:
    @@ -5607,8 +5610,7 @@ 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;
    @@ -7733,6 +7735,9 @@ 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;

    --
    2.34.1


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