[PATCH 5.18 1088/1095] bpf: Fix sparse warning for bpf_kptr_xchg_proto

[Greg Kroah-Hartman]

From: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>

commit 5b74c690e1c55953ec99fd9dab74f72dbee4fe95 upstream.

Kernel Test Robot complained about missing static storage class
annotation for bpf_kptr_xchg_proto variable.

sparse: symbol 'bpf_kptr_xchg_proto' was not declared. Should it be static?

This caused by missing extern definition in the header. Add it to
suppress the sparse warning.

Fixes: c0a5a21c25f3 ("bpf: Allow storing referenced kptr in map")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
Link: https://lore.kernel.org/r/20220511194654.765705-2-memxor@xxxxxxxxx
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 include/linux/bpf.h |    1 +
 1 file changed, 1 insertion(+)

--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2228,6 +2228,7 @@ extern const struct bpf_func_proto bpf_f
 extern const struct bpf_func_proto bpf_loop_proto;
 extern const struct bpf_func_proto bpf_strncmp_proto;
 extern const struct bpf_func_proto bpf_copy_from_user_task_proto;
+extern const struct bpf_func_proto bpf_kptr_xchg_proto;
 
 const struct bpf_func_proto *tracing_prog_func_proto(
   enum bpf_func_id func_id, const struct bpf_prog *prog);