Commit f6161a8f authored Nov 20, 2018 by Yonghong Song Committed by Alexei Starovoitov Nov 20, 2018

bpf: fix a compilation error when CONFIG_BPF_SYSCALL is not defined

Kernel test robot (lkp@intel.com) reports a compilation error at
  https://www.spinics.net/lists/netdev/msg534913.html


introduced by commit 838e9690 ("bpf: Introduce bpf_func_info").

If CONFIG_BPF is defined and CONFIG_BPF_SYSCALL is not defined,
the following error will appear:
  kernel/bpf/core.c:414: undefined reference to `btf_type_by_id'
  kernel/bpf/core.c:415: undefined reference to `btf_name_by_offset'

When CONFIG_BPF_SYSCALL is not defined,
let us define stub inline functions for btf_type_by_id()
and btf_name_by_offset() in include/linux/btf.h.
This way, the compilation failure can be avoided.

Fixes: 838e9690 ("bpf: Introduce bpf_func_info")
Reported-by: kbuild test robot <lkp@intel.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

parent 740baecd

include/linux/btf.h

+14 −0

Original line number	Diff line number	Diff line
		@@ -46,7 +46,21 @@ void btf_type_seq_show(const struct btf btf, u32 type_id, void obj,
		struct seq_file *m);
		int btf_get_fd_by_id(u32 id);
		u32 btf_id(const struct btf *btf);

		#ifdef CONFIG_BPF_SYSCALL
		const struct btf_type btf_type_by_id(const struct btf btf, u32 type_id);
		const char btf_name_by_offset(const struct btf btf, u32 offset);
		#else
		static inline const struct btf_type btf_type_by_id(const struct btf btf,
		u32 type_id)
		{
		return NULL;
		}
		static inline const char btf_name_by_offset(const struct btf btf,
		u32 offset)
		{
		return NULL;
		}
		#endif

		#endif

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