Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx> writes: > On Mon, Sep 27, 2021 at 06:07:30PM IST, Toke Høiland-Jørgensen wrote: >> Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx> writes: >> >> > In xdp_redirect_map_multi.bpf.c, on newer kernels samples compilation >> > fails when vmlinux.h is generated from a kernel supporting broadcast for >> > devmap. Hence, avoid naming collisions to prevent build failure. >> >> Hmm, shouldn't the sample just be getting the value from the kernel in >> the first place instead of re-defining it? >> > > True, but in general my assumption was that it could be built with a older > kernel's vmlinux.h, but be ran on a newer one. If that's not strictly needed, I > can just drop it. But the code is still making assumptions about the contents of vmlinux.h, isn't it? Like the size (and existence) of struct bpf_devmap_val. > This can also be the case if you haven't built the kernel in the tree > (just did a make headers_install), it then falls back to generating > the vmlinux.h from the running kernel. This seems a bit brittle. Given that the samples are distributed with the kernel sources, I would expect them to always correspond to the kernel version in the source tree they're in and not randomly break if the running kernel is different... -Toke
