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Message-ID: <c4871911-5cb6-4237-a0a3-001ecb8bd7e5@kernel.dk>
Date: Thu, 14 Mar 2024 10:14:24 -0600
From: Jens Axboe <axboe@...nel.dk>
To: Pavel Begunkov <asml.silence@...il.com>, David Wei <dw@...idwei.uk>,
io-uring@...r.kernel.org, netdev@...r.kernel.org
Cc: Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
Jesper Dangaard Brouer <hawk@...nel.org>, David Ahern <dsahern@...nel.org>,
Mina Almasry <almasrymina@...gle.com>
Subject: Re: [RFC PATCH v4 13/16] io_uring: add io_recvzc request
(Apparently this went out without my comments attached, only one thing
worth noting so repeating that)
>>> @@ -695,7 +701,7 @@ static inline bool io_recv_finish(struct io_kiocb *req, int *ret,
>>> unsigned int cflags;
>>> cflags = io_put_kbuf(req, issue_flags);
>>> - if (msg->msg_inq && msg->msg_inq != -1)
>>> + if (msg && msg->msg_inq && msg->msg_inq != -1)
>>> cflags |= IORING_CQE_F_SOCK_NONEMPTY;
>>> if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
>>> @@ -723,7 +729,7 @@ static inline bool io_recv_finish(struct io_kiocb *req, int *ret,
>>> goto enobufs;
>>> /* Known not-empty or unknown state, retry */
>>> - if (cflags & IORING_CQE_F_SOCK_NONEMPTY || msg->msg_inq == -1) {
>>> + if (cflags & IORING_CQE_F_SOCK_NONEMPTY || (msg && msg->msg_inq == -1)) {
>>> if (sr->nr_multishot_loops++ < MULTISHOT_MAX_RETRY)
>>> return false;
>>> /* mshot retries exceeded, force a requeue */
>>
>> Maybe refactor this a bit so that you don't need to add these NULL
>> checks? That seems pretty fragile, hard to read, and should be doable
>> without extra checks.
>
> That chunk can be completely thrown away, we're not using
> io_recv_finish() here anymore
OK good!
>>> @@ -1053,6 +1058,85 @@ struct io_zc_rx_ifq *io_zc_verify_sock(struct io_kiocb *req,
>>> return ifq;
>>> }
>>> +int io_recvzc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
>>> +{
>>> + struct io_recvzc *zc = io_kiocb_to_cmd(req, struct io_recvzc);
>>> +
>>> + /* non-iopoll defer_taskrun only */
>>> + if (!req->ctx->task_complete)
>>> + return -EINVAL;
>>
>> What's the reasoning behind this?
>
> CQ locking, see the comment a couple lines below
My question here was more towards "is this something we want to do".
Maybe this is just a temporary work-around and it's nothing to discuss,
but I'm not sure we want to have opcodes only work on certain ring
setups.
--
Jens Axboe
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