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 3CBBBC77B70 for ; Tue, 11 Apr 2023 16:10:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230051AbjDKQKv (ORCPT ); Tue, 11 Apr 2023 12:10:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39744 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229949AbjDKQKs (ORCPT ); Tue, 11 Apr 2023 12:10:48 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8657449E2 for ; Tue, 11 Apr 2023 09:09:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681229378; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3NDU5jXq/4v/LV+bxGx3XkpL7tqbKHeQbhHOvrmy/nQ=; b=MS5z4Vm3TsjNc8oq+ztF/IjMHlgnWWYu1Ha8Ew9ByFu3Eb7XUW/v0ICbkvno69WYOwMtvY L/vOLoW7iCvLdSJ0A4xzEDikN4PPqrBeAkZauzn1zy5KLtp4aFJFlFRsLfUZPo8tt1dhAK sPF3mfR6PPlWfM/0fjdRNYDAiRm/mLY= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-515-CzdXFcUzNB6gKH1eCyNJrg-1; Tue, 11 Apr 2023 12:09:32 -0400 X-MC-Unique: CzdXFcUzNB6gKH1eCyNJrg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C58DD38149B1; Tue, 11 Apr 2023 16:09:31 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id AA4EE47CDC; Tue, 11 Apr 2023 16:09:29 +0000 (UTC) From: David Howells To: netdev@vger.kernel.org Cc: David Howells , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Willem de Bruijn , David Ahern , Matthew Wilcox , Al Viro , Christoph Hellwig , Jens Axboe , Jeff Layton , Christian Brauner , Chuck Lever III , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH net-next v6 07/18] tcp: Support MSG_SPLICE_PAGES Date: Tue, 11 Apr 2023 17:08:51 +0100 Message-Id: <20230411160902.4134381-8-dhowells@redhat.com> In-Reply-To: <20230411160902.4134381-1-dhowells@redhat.com> References: <20230411160902.4134381-1-dhowells@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Make TCP's sendmsg() support MSG_SPLICE_PAGES. This causes pages to be spliced or copied (if it cannot be spliced) from the source iterator. This allows ->sendpage() to be replaced by something that can handle multiple multipage folios in a single transaction. Signed-off-by: David Howells cc: Eric Dumazet cc: "David S. Miller" cc: David Ahern cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Matthew Wilcox cc: netdev@vger.kernel.org --- Notes: ver #6) - Use common helper. net/ipv4/tcp.c | 43 ++++++++++++++++++++++++++++++++++++------- 1 file changed, 36 insertions(+), 7 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index fd68d49490f2..0b2213da5aaf 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1221,7 +1221,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) int flags, err, copied = 0; int mss_now = 0, size_goal, copied_syn = 0; int process_backlog = 0; - bool zc = false; + int zc = 0; long timeo; flags = msg->msg_flags; @@ -1232,17 +1232,22 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) if (msg->msg_ubuf) { uarg = msg->msg_ubuf; net_zcopy_get(uarg); - zc = sk->sk_route_caps & NETIF_F_SG; + if (sk->sk_route_caps & NETIF_F_SG) + zc = 1; } else if (sock_flag(sk, SOCK_ZEROCOPY)) { uarg = msg_zerocopy_realloc(sk, size, skb_zcopy(skb)); if (!uarg) { err = -ENOBUFS; goto out_err; } - zc = sk->sk_route_caps & NETIF_F_SG; - if (!zc) + if (sk->sk_route_caps & NETIF_F_SG) + zc = MSG_ZEROCOPY; + else uarg_to_msgzc(uarg)->zerocopy = 0; } + } else if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES) && size) { + if (sk->sk_route_caps & NETIF_F_SG) + zc = MSG_SPLICE_PAGES; } if (unlikely(flags & MSG_FASTOPEN || inet_sk(sk)->defer_connect) && @@ -1305,7 +1310,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) goto do_error; while (msg_data_left(msg)) { - int copy = 0; + ssize_t copy = 0; skb = tcp_write_queue_tail(sk); if (skb) @@ -1346,7 +1351,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) if (copy > msg_data_left(msg)) copy = msg_data_left(msg); - if (!zc) { + if (zc == 0) { bool merge = true; int i = skb_shinfo(skb)->nr_frags; struct page_frag *pfrag = sk_page_frag(sk); @@ -1391,7 +1396,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) page_ref_inc(pfrag->page); } pfrag->offset += copy; - } else { + } else if (zc == MSG_ZEROCOPY) { /* First append to a fragless skb builds initial * pure zerocopy skb */ @@ -1412,6 +1417,30 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) if (err < 0) goto do_error; copy = err; + } else if (zc == MSG_SPLICE_PAGES) { + /* Splice in data if we can; copy if we can't. */ + if (tcp_downgrade_zcopy_pure(sk, skb)) + goto wait_for_space; + copy = tcp_wmem_schedule(sk, copy); + if (!copy) + goto wait_for_space; + + err = skb_splice_from_iter(skb, &msg->msg_iter, copy, + sk->sk_allocation); + if (err < 0) { + if (err == -EMSGSIZE) { + tcp_mark_push(tp, skb); + goto new_segment; + } + goto do_error; + } + copy = err; + + if (!(flags & MSG_NO_SHARED_FRAGS)) + skb_shinfo(skb)->flags |= SKBFL_SHARED_FRAG; + + sk_wmem_queued_add(sk, copy); + sk_mem_charge(sk, copy); } if (!copied)