On Wed, Jan 27, 2021 at 9:15 AM Denis Salopek [off-list ref] 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 <redacted>
Cc: Juraj Vijtiuk <redacted>
Cc: Luka Oreskovic <redacted>
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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