[PATCH 4/7] libbpf: Return const btf_member from btf_members inline function

[Jiri Olsa]

I'm getting following errors when compiling with -Wcast-qual:

  bpf/btf.h: In function ‘btf_member* btf_members(const btf_type*)’:
  bpf/btf.h:264:36: warning: cast from type ‘const btf_type*’ to type
  ‘btf_member*’ casts away qualifiers [-Wcast-qual]
    264 |  return (struct btf_member *)(t + 1);
        |                                    ^

The argument is const so the cast to following struct btf_member
pointer should be const as well. Casting the const away in btf.c
call where it's correctly used without const in deduplication
code.

Signed-off-by: Jiri Olsa <jo...@kernel.org>
---
 tools/lib/bpf/btf.c    | 4 ++--
 tools/lib/bpf/btf.h    | 4 ++--
 tools/lib/bpf/libbpf.c | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 5a39e9506760..560d1ae33675 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -1463,7 +1463,7 @@ static int btf_for_each_str_off(struct btf_dedup *d, 
str_off_fn_t fn, void *ctx)
                switch (btf_kind(t)) {
                case BTF_KIND_STRUCT:
                case BTF_KIND_UNION: {
-                       struct btf_member *m = btf_members(t);
+                       struct btf_member *m = (struct btf_member *) 
btf_members(t);
                        __u16 vlen = btf_vlen(t);
 
                        for (j = 0; j < vlen; j++) {
@@ -2797,7 +2797,7 @@ static int btf_dedup_remap_type(struct btf_dedup *d, 
__u32 type_id)
 
        case BTF_KIND_STRUCT:
        case BTF_KIND_UNION: {
-               struct btf_member *member = btf_members(t);
+               struct btf_member *member = (struct btf_member *) 
btf_members(t);
                __u16 vlen = btf_vlen(t);
 
                for (i = 0; i < vlen; i++) {
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index 3b3216fa348f..cd1bd018ba8b 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -259,9 +259,9 @@ static inline const struct btf_enum *btf_enum(const struct 
btf_type *t)
        return (const struct btf_enum *)(t + 1);
 }
 
-static inline struct btf_member *btf_members(const struct btf_type *t)
+static inline const struct btf_member *btf_members(const struct btf_type *t)
 {
-       return (struct btf_member *)(t + 1);
+       return (const struct btf_member *)(t + 1);
 }
 
 /* Get bit offset of a member with specified index. */
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 2233f919dd88..7d3d6284dd2e 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1389,7 +1389,7 @@ static void bpf_object__sanitize_btf(struct bpf_object 
*obj)
                } else if (!has_datasec && btf_is_datasec(t)) {
                        /* replace DATASEC with STRUCT */
                        const struct btf_var_secinfo *v = btf_var_secinfos(t);
-                       struct btf_member *m = btf_members(t);
+                       struct btf_member *m = (struct btf_member *) 
btf_members(t);
                        struct btf_type *vt;
                        char *name;
 
-- 
2.21.0