bpf: Expose check_uarg_tail_zero()

This patch exposes check_uarg_tail_zero() which will
be reused by a later BTF patch.  Its name is changed to
bpf_check_uarg_tail_zero().

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

include/linux/bpf.h

@@ -463,6 +463,8 @@ int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
 int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value);
 
 int bpf_get_file_flag(int flags);
+int bpf_check_uarg_tail_zero(void __user *uaddr, size_t expected_size,
+			     size_t actual_size);
 
 /* memcpy that is used with 8-byte aligned pointers, power-of-8 size and
  * forced to use 'long' read/writes to try to atomically copy long counters.