Re: [PATCH bpf-next] bpf: add lookup_and_delete_elem support to hashtab

[Andrii Nakryiko <andrii.nakryiko@gmail.com>]

On Wed, Jan 27, 2021 at 9:15 AM Denis Salopek <denis.salopek@sartura.hr> wrote:
>
> Extend the existing bpf_map_lookup_and_delete_elem() functionality to
> hashtab maps, in addition to stacks and queues.
> Create a new hashtab bpf_map_ops function that does lookup and deletion
> of the element under the same bucket lock and add the created map_ops to
> bpf.h.
> Add the appropriate test case to 'maps' selftests.
>
> Signed-off-by: Denis Salopek <denis.salopek@sartura.hr>
> Cc: Juraj Vijtiuk <juraj.vijtiuk@sartura.hr>
> Cc: Luka Oreskovic <luka.oreskovic@sartura.hr>
> Cc: Luka Perkov <luka.perkov@sartura.hr>
> ---

I think this patch somehow got lost, even though it seems like a good
addition. I'd recommend rebasing and re-submitting to let people take
a fresh look at this.

It would also be nice to have a test_progs test added, not just
test_maps. I'd also look at supporting lookup_and_delete for other
kinds of hash maps (LRU, per-CPU), so that the support is more
complete. Thanks!

>  include/linux/bpf.h                     |  1 +
>  kernel/bpf/hashtab.c                    | 38 +++++++++++++++++++++++++
>  kernel/bpf/syscall.c                    |  9 ++++++
>  tools/testing/selftests/bpf/test_maps.c |  7 +++++
>  4 files changed, 55 insertions(+)
>

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