Commit fc9702273e2e ("bpf: Add mmap() support for BPF_MAP_TYPE_ARRAY")
added code that calls vmalloc_user_node_flags() and therefore requires
mm/vmalloc.c. However, that file is not built for the !CONFIG_MMU case.
This leads to a build failure when using ARM with the config provided
by at least one particular kbuild test robot report [1].
[1] https://lore/kernel.org/r/201911251639.UWS3hE3Y%lkp@xxxxxxxxx
Fix the build by providing a stub function for __bpf_map_area_alloc().
Fixes: fc9702273e2e ("bpf: Add mmap() support for BPF_MAP_TYPE_ARRAY")
Reported-by: kbuild test robot <lkp@xxxxxxxxx>
Cc: Andrii Nakryiko <andriin@xxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: John Fastabend <john.fastabend@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>