From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B71B5C7EE2C for ; Mon, 15 May 2023 17:32:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244356AbjEORcy (ORCPT ); Mon, 15 May 2023 13:32:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244346AbjEORci (ORCPT ); Mon, 15 May 2023 13:32:38 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D3E086582 for ; Mon, 15 May 2023 10:29:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7107762D16 for ; Mon, 15 May 2023 17:29:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9613BC4339C; Mon, 15 May 2023 17:29:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1684171797; bh=HND/fi/LqnYdV2Zi8PU1A7sFl5ZI6OJIRED2DbA++Ck=; h=Date:Subject:To:References:From:In-Reply-To:From; b=XiRplXtyYExfvilBR2iLNVYsspJo/KXDLuQSOk4j4nuogvDxo1OY4kRrQWW2rqQS/ 9Fuo8DH6r5LLGKFdb6ok23FhAveft33S1H9dUan0MgPIx250D28Ytqk46RReBiW+t6 GQ16W4t8W530TUBsOv2IADOpHVW31tL5LqhxXRGaEPsVKX4j1qv8Cwrit1yXuSGgys m6bmq3NyuRcO94ozmN9iag8QwlYjYA4HsNdhQiA6pRBhjnSmpacX12QueagbabFvpn Lnt1WpdRZHvY5vSnU1f88LcvOOzTvIM6jQ9jUwTLBndvQP0tBOW/DERKNkOEjH8bdH dhNDgYTs4pIrg== Message-ID: <99faed2d-8ea6-fc85-7f21-e15b24d041f1@kernel.org> Date: Mon, 15 May 2023 11:29:56 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH net-next 2/2] net/tcp: optimise io_uring zc ubuf refcounting Content-Language: en-US To: Pavel Begunkov , io-uring@vger.kernel.org, netdev@vger.kernel.org, edumazet@google.com, davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com References: From: David Ahern In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 5/15/23 10:06 AM, Pavel Begunkov wrote: > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > index 40f591f7fce1..3d18e295bb2f 100644 > --- a/net/ipv4/tcp.c > +++ b/net/ipv4/tcp.c > @@ -1231,7 +1231,6 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) > if ((flags & MSG_ZEROCOPY) && size) { > if (msg->msg_ubuf) { > uarg = msg->msg_ubuf; > - net_zcopy_get(uarg); > zc = sk->sk_route_caps & NETIF_F_SG; > } else if (sock_flag(sk, SOCK_ZEROCOPY)) { > skb = tcp_write_queue_tail(sk); > @@ -1458,7 +1457,9 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) > tcp_push(sk, flags, mss_now, tp->nonagle, size_goal); > } > out_nopush: > - net_zcopy_put(uarg); > + /* msg->msg_ubuf is pinned by the caller so we don't take extra refs */ > + if (uarg && !msg->msg_ubuf) > + net_zcopy_put(uarg); > return copied + copied_syn; > > do_error: > @@ -1467,7 +1468,9 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) > if (copied + copied_syn) > goto out; > out_err: > - net_zcopy_put_abort(uarg, true); > + /* msg->msg_ubuf is pinned by the caller so we don't take extra refs */ > + if (uarg && !msg->msg_ubuf) > + net_zcopy_put_abort(uarg, true); > err = sk_stream_error(sk, flags, err); > /* make sure we wake any epoll edge trigger waiter */ > if (unlikely(tcp_rtx_and_write_queues_empty(sk) && err == -EAGAIN)) { Both net_zcopy_put_abort and net_zcopy_put have an `if (uarg)` check.