From: luoliang __COMPAT_read_enum() and __COMPAT_struct_has_field() open-code the vlen lookup via the raw BTF_INFO_VLEN(t->info) UAPI macro, whose result type is __u32 (t->info is __u32 and 0xffff is promoted to unsigned). Comparing it against the int loop counter triggers -Wsign-compare in every example scheduler that includes compat.h. libbpf already exposes btf_vlen() for exactly this purpose; it returns __u16, the natural width of the vlen field, and the usual integer promotions turn the 'int < __u16' comparison into a plain 'int < int' so the warning goes away without any cast. This matches the pattern already used in-kernel (e.g. kernel/bpf/inode.c) and in tools/bpf/bpftool. Replace the three open-coded lookups with btf_vlen(t). No functional change. Signed-off-by: Liang Luo --- tools/sched_ext/include/scx/compat.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/sched_ext/include/scx/compat.h b/tools/sched_ext/include/scx/compat.h index 039854c490d5..df5ca1ce20f6 100644 --- a/tools/sched_ext/include/scx/compat.h +++ b/tools/sched_ext/include/scx/compat.h @@ -42,7 +42,7 @@ static inline bool __COMPAT_read_enum(const char *type, const char *name, u64 *v if (btf_is_enum(t)) { struct btf_enum *e = btf_enum(t); - for (i = 0; i < BTF_INFO_VLEN(t->info); i++) { + for (i = 0; i < btf_vlen(t); i++) { n = btf__name_by_offset(__COMPAT_vmlinux_btf, e[i].name_off); SCX_BUG_ON(!n, "btf__name_by_offset()"); if (!strcmp(n, name)) { @@ -53,7 +53,7 @@ static inline bool __COMPAT_read_enum(const char *type, const char *name, u64 *v } else if (btf_is_enum64(t)) { struct btf_enum64 *e = btf_enum64(t); - for (i = 0; i < BTF_INFO_VLEN(t->info); i++) { + for (i = 0; i < btf_vlen(t); i++) { n = btf__name_by_offset(__COMPAT_vmlinux_btf, e[i].name_off); SCX_BUG_ON(!n, "btf__name_by_offset()"); if (!strcmp(n, name)) { @@ -97,7 +97,7 @@ static inline bool __COMPAT_struct_has_field(const char *type, const char *field m = btf_members(t); - for (i = 0; i < BTF_INFO_VLEN(t->info); i++) { + for (i = 0; i < btf_vlen(t); i++) { n = btf__name_by_offset(__COMPAT_vmlinux_btf, m[i].name_off); SCX_BUG_ON(!n, "btf__name_by_offset()"); if (!strcmp(n, field)) -- 2.43.0