admin/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2025-12-07 20:06:24 +00:00
Code Issues Packages Projects Releases Wiki Activity

libbpf: split feature detectors definitions from cached results

Browse Source 
Split a list of supported feature detectors with their corresponding
callbacks from actual cached supported/missing values. This will allow
to have more flexible per-token or per-object feature detectors in
subsequent refactorings.

Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231213190842.3844987-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Andrii Nakryiko
2023-12-13 11:08:34 -08:00
committed by Alexei Starovoitov
parent f5fdb51fb9
commit c6c5be3eee
1 changed files with 12 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
tools/lib/bpf/libbpf.c
View File

@@ -4999,12 +4999,17 @@ enum kern_feature_result {
FEAT_MISSING = 2,
};
struct kern_feature_cache {
enum kern_feature_result res[__FEAT_CNT];
};
typedef int (*feature_probe_fn)(void);
static struct kern_feature_cache feature_cache;
static struct kern_feature_desc {
const char *desc;
feature_probe_fn probe;
enum kern_feature_result res;
} feature_probes[__FEAT_CNT] = {
[FEAT_PROG_NAME] = {
"BPF program name", probe_kern_prog_name,
@@ -5072,6 +5077,7 @@ static struct kern_feature_desc {
bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id)
{
struct kern_feature_desc *feat = &feature_probes[feat_id];
struct kern_feature_cache *cache = &feature_cache;
int ret;
if (obj && obj->gen_loader)
@@ -5080,19 +5086,19 @@ bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id)
*/
return true;
if (READ_ONCE(feat->res) == FEAT_UNKNOWN) {
if (READ_ONCE(cache->res[feat_id]) == FEAT_UNKNOWN) {
ret = feat->probe();
if (ret > 0) {
WRITE_ONCE(feat->res, FEAT_SUPPORTED);
WRITE_ONCE(cache->res[feat_id], FEAT_SUPPORTED);
} else if (ret == 0) {
WRITE_ONCE(feat->res, FEAT_MISSING);
WRITE_ONCE(cache->res[feat_id], FEAT_MISSING);
} else {
pr_warn("Detection of kernel %s support failed: %d\n", feat->desc, ret);
WRITE_ONCE(feat->res, FEAT_MISSING);
WRITE_ONCE(cache->res[feat_id], FEAT_MISSING);
}
}
return READ_ONCE(feat->res) == FEAT_SUPPORTED;
return READ_ONCE(cache->res[feat_id]) == FEAT_SUPPORTED;
}
static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd)