bpf, sockmap: Reschedule is now done through backlog

[ Upstream commit bce22552f92ea7c577f49839b8e8f7d29afaf880 ]

Now that the backlog manages the reschedule() logic correctly we can drop
the partial fix to reschedule from recvmsg hook.

Rescheduling on recvmsg hook was added to address a corner case where we
still had data in the backlog state but had nothing to kick it and
reschedule the backlog worker to run and finish copying data out of the
state. This had a couple limitations, first it required user space to
kick it introducing an unnecessary EBUSY and retry. Second it only
handled the ingress case and egress redirects would still be hung.

With the correct fix, pushing the reschedule logic down to where the
enomem error occurs we can drop this fix.

Fixes: bec217197b412 ("skmsg: Schedule psock work if the cached skb exists on the psock")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20230523025618.113937-4-john.fastabend@gmail.com
Stable-dep-of: 405df89dd52c ("bpf, sockmap: Improved check for empty queue")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index ccd5b9568bb8570f710bc3eb688711ac26600a26..8667163c8efe53532a2566e5b52be3c042315a1f 100644 (file)
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -481,8 +481,6 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
                msg_rx = sk_psock_peek_msg(psock);
        }
 out:
-       if (psock->work_state.skb && copied > 0)
-               schedule_delayed_work(&psock->work, 0);
        return copied;
 }
 EXPORT_SYMBOL_GPL(sk_msg_recvmsg);