libbpf: Fix is_pow_of_2

Move the correct definition from linker.c into libbpf_internal.h.

Fixes: 0087a68 ("libbpf: Automatically fix up BPF_MAP_TYPE_RINGBUF size, if necessary")
Reported-by: Yuze Chi <chiyuze@google.com>
Signed-off-by: Yuze Chi <chiyuze@google.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220603055156.2830463-1-irogers@google.com

Author: Yuze Chi

tools/lib/bpf/libbpf.c

@@ -5071,11 +5071,6 @@ bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
 
 static void bpf_map__destroy(struct bpf_map *map);
 
-static bool is_pow_of_2(size_t x)
-{
-	return x && (x & (x - 1));
-}
-
 static size_t adjust_ringbuf_sz(size_t sz)
 {
 	__u32 page_sz = sysconf(_SC_PAGE_SIZE);

tools/lib/bpf/libbpf_internal.h

@@ -580,4 +580,9 @@ struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man,
 					   const char *usdt_provider, const char *usdt_name,
 					   __u64 usdt_cookie);
 
+static inline bool is_pow_of_2(size_t x)
+{
+	return x && (x & (x - 1)) == 0;
+}
+
 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */

tools/lib/bpf/linker.c

@@ -697,11 +697,6 @@ static int linker_load_obj_file(struct bpf_linker *linker, const char *filename,
 	return err;
 }
 
-static bool is_pow_of_2(size_t x)
-{
-	return x && (x & (x - 1)) == 0;
-}
-
 static int linker_sanity_check_elf(struct src_obj *obj)
 {
 	struct src_sec *sec;