From nobody Wed Feb 11 12:35:38 2026 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 520C0C7618D for ; Thu, 6 Apr 2023 09:45:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236827AbjDFJpT (ORCPT ); Thu, 6 Apr 2023 05:45:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52820 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236618AbjDFJop (ORCPT ); Thu, 6 Apr 2023 05:44:45 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D2AFA83E4 for ; Thu, 6 Apr 2023 02:43:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680774216; 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=DWLW7zv5E95PcNMvzADLtZC4cFCYwscW+4auTp2qbuU=; b=a1OUmHAjCNCQXlK+zBGRs38y+NnH4cTuau0gBa9InFov9qHaI0KeqASNt98jKDiBXyb+0v ZV+Et4YNoLnxVRJtncdeb6/JjAR87uPHC07oH5uVJ8X/IVmifldj7mPyC3pDAc6dcwerA9 v+yY3AniwOjtTFpGt+0EnsGKWls11q8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-44-vEeTLutcMDW3WDa_hFgwtA-1; Thu, 06 Apr 2023 05:43:31 -0400 X-MC-Unique: vEeTLutcMDW3WDa_hFgwtA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0F9C2800B23; Thu, 6 Apr 2023 09:43:31 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id F03781121314; Thu, 6 Apr 2023 09:43:28 +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 , 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, David Ahern Subject: [PATCH net-next v5 13/19] ip, udp: Support MSG_SPLICE_PAGES Date: Thu, 6 Apr 2023 10:42:39 +0100 Message-Id: <20230406094245.3633290-14-dhowells@redhat.com> In-Reply-To: <20230406094245.3633290-1-dhowells@redhat.com> References: <20230406094245.3633290-1-dhowells@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Make IP/UDP sendmsg() support MSG_SPLICE_PAGES. This causes pages to 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: Willem de Bruijn cc: David Ahern cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Matthew Wilcox cc: netdev@vger.kernel.org --- net/ipv4/ip_output.c | 47 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 22a90a9392eb..c6c318eb3d37 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -957,6 +957,41 @@ csum_page(struct page *page, int offset, int copy) return csum; } =20 +/* + * Add (or copy) data pages for MSG_SPLICE_PAGES. + */ +static int __ip_splice_pages(struct sock *sk, struct sk_buff *skb, + void *from, int *pcopy) +{ + struct msghdr *msg =3D from; + struct page *page =3D NULL, **pages =3D &page; + ssize_t copy =3D *pcopy; + size_t off; + int err; + + copy =3D iov_iter_extract_pages(&msg->msg_iter, &pages, copy, 1, 0, &off); + if (copy <=3D 0) + return copy ?: -EIO; + + err =3D skb_append_pagefrags(skb, page, off, copy); + if (err < 0) { + iov_iter_revert(&msg->msg_iter, copy); + return err; + } + + if (skb->ip_summed =3D=3D CHECKSUM_NONE) { + __wsum csum; + + csum =3D csum_page(page, off, copy); + skb->csum =3D csum_block_add(skb->csum, csum, skb->len); + } + + skb_len_add(skb, copy); + refcount_add(copy, &sk->sk_wmem_alloc); + *pcopy =3D copy; + return 0; +} + static int __ip_append_data(struct sock *sk, struct flowi4 *fl4, struct sk_buff_head *queue, @@ -1048,6 +1083,14 @@ static int __ip_append_data(struct sock *sk, skb_zcopy_set(skb, uarg, &extra_uref); } } + } else if ((flags & MSG_SPLICE_PAGES) && length) { + if (inet->hdrincl) + return -EPERM; + if (rt->dst.dev->features & NETIF_F_SG) + /* We need an empty buffer to attach stuff to */ + paged =3D true; + else + flags &=3D ~MSG_SPLICE_PAGES; } =20 cork->length +=3D length; @@ -1207,6 +1250,10 @@ static int __ip_append_data(struct sock *sk, err =3D -EFAULT; goto error; } + } else if (flags & MSG_SPLICE_PAGES) { + err =3D __ip_splice_pages(sk, skb, from, ©); + if (err < 0) + goto error; } else if (!zc) { int i =3D skb_shinfo(skb)->nr_frags;