Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   David Vernet <void@manifault.com>
To:     bpf@vger.kernel.org
Cc:     andrii@kernel.org, ast@kernel.org, martin.lau@linux.dev,
        daniel@iogearbox.net, song@kernel.org, yhs@fb.com,
        john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
        haoluo@google.com, jolsa@kernel.org, linux-kernel@vger.kernel.org,
        kernel-team@fb.com
Subject: [PATCH 0/2] Allow bpf_user_ringbuf_drain() callbacks to return 1
Date:   Wed, 12 Oct 2022 18:20:13 -0500
Message-Id: <20221012232015.1510043-1-void@manifault.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The bpf_user_ringbuf_drain() helper function allows a BPF program to
specify a callback that is invoked when draining entries from a
BPF_MAP_TYPE_USER_RINGBUF ring buffer map. The API is meant to allow the
callback to return 0 if it wants to continue draining samples, and 1 if
it's done draining. Unfortunately, bpf_user_ringbuf_drain() landed shortly
after commit 1bfe26fb0827 ("bpf: Add verifier support for custom
callback return range"), which changed the default behavior of callbacks
to only support returning 0, and the corresponding necessary change to
bpf_user_ringbuf_drain() callbacks was missed.

This patch set fixes this oversight, and updates the user_ringbuf
selftests to return 1 in a callback to catch future instances of
regression.

This patch set should be merged to the bpf tree.

David Vernet (2):
  bpf: Allow bpf_user_ringbuf_drain() callbacks to return 1
  selftests/bpf: Make bpf_user_ringbuf_drain() selftest callback return
    1

 kernel/bpf/verifier.c                                    | 1 +
 tools/testing/selftests/bpf/progs/user_ringbuf_success.c | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

-- 
2.38.0