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| author | Andrii Nakryiko <andriin@fb.com> | 2020-01-09 19:42:46 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-01-09 21:17:01 -0800 |
| commit | 492ab0205f500ebd20b4f0c9e95a1ba007b0c542 (patch) | |
| tree | 46cf10d9d9f327bc4d67268d1b91934a9303e0b5 /tools/lib | |
| parent | f5bfcd953d811dbb8913de36b96b38da6bb62135 (diff) | |
| download | linux-492ab0205f500ebd20b4f0c9e95a1ba007b0c542.tar.gz linux-492ab0205f500ebd20b4f0c9e95a1ba007b0c542.tar.bz2 linux-492ab0205f500ebd20b4f0c9e95a1ba007b0c542.zip | |
libbpf: Make bpf_map order and indices stable
Currently, libbpf re-sorts bpf_map structs after all the maps are added and
initialized, which might change their relative order and invalidate any
bpf_map pointer or index taken before that. This is inconvenient and
error-prone. For instance, it can cause .kconfig map index to point to a wrong
map.
Furthermore, libbpf itself doesn't rely on any specific ordering of bpf_maps,
so it's just an unnecessary complication right now. This patch drops sorting
of maps and makes their relative positions fixed. If efficient index is ever
needed, it's better to have a separate array of pointers as a search index,
instead of reordering bpf_map struct in-place. This will be less error-prone
and will allow multiple independent orderings, if necessary (e.g., either by
section index or by name).
Fixes: 166750bc1dd2 ("libbpf: Support libbpf-provided extern variables")
Reported-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200110034247.1220142-1-andriin@fb.com
Diffstat (limited to 'tools/lib')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 14 |
1 files changed, 0 insertions, 14 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 35a4422ef655..ee2620b2aa55 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1123,16 +1123,6 @@ bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size) return 0; } -static int compare_bpf_map(const void *_a, const void *_b) -{ - const struct bpf_map *a = _a; - const struct bpf_map *b = _b; - - if (a->sec_idx != b->sec_idx) - return a->sec_idx - b->sec_idx; - return a->sec_offset - b->sec_offset; -} - static bool bpf_map_type__is_map_in_map(enum bpf_map_type type) { if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS || @@ -2196,10 +2186,6 @@ static int bpf_object__init_maps(struct bpf_object *obj, if (err) return err; - if (obj->nr_maps) { - qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), - compare_bpf_map); - } return 0; } |