From nobody Sun Dec 14 22:12:05 2025 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 6CF40EB64DD for ; Fri, 23 Jun 2023 22:56:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232494AbjFWW42 (ORCPT ); Fri, 23 Jun 2023 18:56:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231834AbjFWW4O (ORCPT ); Fri, 23 Jun 2023 18:56:14 -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 5F5202709 for ; Fri, 23 Jun 2023 15:55:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1687560928; 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=96le6Nv7f7Jm2em1nCUehde2Ld5Ng9GbgAM0NyDY2H8=; b=irqyeMHGueA41WpjvkmmFLE373NjfuT8TSLHIg8Heb7miYm/ivTRYr+h7c3zDBwQ1XCrej yNOyqHClanlJidBB1XaFcwPSFF7yvrnj0Qnt5BtrprPP/QvT8wos3RPkfmU2QASGB+WHLS 17feecjMBkMlnbzXkKzupeFNwqdQT58= 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-470-JAj_tgg_MAmagZcoZ9ODJA-1; Fri, 23 Jun 2023 18:55:25 -0400 X-MC-Unique: JAj_tgg_MAmagZcoZ9ODJA-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 C11F21C05ED2; Fri, 23 Jun 2023 22:55:24 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 594DEF5ADA; Fri, 23 Jun 2023 22:55:23 +0000 (UTC) From: David Howells To: netdev@vger.kernel.org Cc: David Howells , Alexander Duyck , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Willem de Bruijn , David Ahern , Matthew Wilcox , Jens Axboe , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v5 02/16] net: Use sendmsg(MSG_SPLICE_PAGES) not sendpage in skb_send_sock() Date: Fri, 23 Jun 2023 23:54:59 +0100 Message-ID: <20230623225513.2732256-3-dhowells@redhat.com> In-Reply-To: <20230623225513.2732256-1-dhowells@redhat.com> References: <20230623225513.2732256-1-dhowells@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Use sendmsg() with MSG_SPLICE_PAGES rather than sendpage in skb_send_sock(). This causes pages to be spliced from the source iterator if possible. This allows ->sendpage() to be replaced by something that can handle multiple multipage folios in a single transaction. Note that this could perhaps be improved to fill out a bvec array with all the frags and then make a single sendmsg call, possibly sticking the header on the front also. Signed-off-by: David Howells cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Matthew Wilcox cc: netdev@vger.kernel.org --- Notes: ver #2) - Wrap lines at 80. net/core/skbuff.c | 50 ++++++++++++++++++++++++++--------------------- 1 file changed, 28 insertions(+), 22 deletions(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index fee2b1c105fe..6c5915efbc17 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2989,32 +2989,32 @@ int skb_splice_bits(struct sk_buff *skb, struct soc= k *sk, unsigned int offset, } EXPORT_SYMBOL_GPL(skb_splice_bits); =20 -static int sendmsg_unlocked(struct sock *sk, struct msghdr *msg, - struct kvec *vec, size_t num, size_t size) +static int sendmsg_locked(struct sock *sk, struct msghdr *msg) { struct socket *sock =3D sk->sk_socket; + size_t size =3D msg_data_left(msg); =20 if (!sock) return -EINVAL; - return kernel_sendmsg(sock, msg, vec, num, size); + + if (!sock->ops->sendmsg_locked) + return sock_no_sendmsg_locked(sk, msg, size); + + return sock->ops->sendmsg_locked(sk, msg, size); } =20 -static int sendpage_unlocked(struct sock *sk, struct page *page, int offse= t, - size_t size, int flags) +static int sendmsg_unlocked(struct sock *sk, struct msghdr *msg) { struct socket *sock =3D sk->sk_socket; =20 if (!sock) return -EINVAL; - return kernel_sendpage(sock, page, offset, size, flags); + return sock_sendmsg(sock, msg); } =20 -typedef int (*sendmsg_func)(struct sock *sk, struct msghdr *msg, - struct kvec *vec, size_t num, size_t size); -typedef int (*sendpage_func)(struct sock *sk, struct page *page, int offse= t, - size_t size, int flags); +typedef int (*sendmsg_func)(struct sock *sk, struct msghdr *msg); static int __skb_send_sock(struct sock *sk, struct sk_buff *skb, int offse= t, - int len, sendmsg_func sendmsg, sendpage_func sendpage) + int len, sendmsg_func sendmsg) { unsigned int orig_len =3D len; struct sk_buff *head =3D skb; @@ -3034,8 +3034,9 @@ static int __skb_send_sock(struct sock *sk, struct sk= _buff *skb, int offset, memset(&msg, 0, sizeof(msg)); msg.msg_flags =3D MSG_DONTWAIT; =20 - ret =3D INDIRECT_CALL_2(sendmsg, kernel_sendmsg_locked, - sendmsg_unlocked, sk, &msg, &kv, 1, slen); + iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &kv, 1, slen); + ret =3D INDIRECT_CALL_2(sendmsg, sendmsg_locked, + sendmsg_unlocked, sk, &msg); if (ret <=3D 0) goto error; =20 @@ -3066,11 +3067,18 @@ static int __skb_send_sock(struct sock *sk, struct = sk_buff *skb, int offset, slen =3D min_t(size_t, len, skb_frag_size(frag) - offset); =20 while (slen) { - ret =3D INDIRECT_CALL_2(sendpage, kernel_sendpage_locked, - sendpage_unlocked, sk, - skb_frag_page(frag), - skb_frag_off(frag) + offset, - slen, MSG_DONTWAIT); + struct bio_vec bvec; + struct msghdr msg =3D { + .msg_flags =3D MSG_SPLICE_PAGES | MSG_DONTWAIT, + }; + + bvec_set_page(&bvec, skb_frag_page(frag), slen, + skb_frag_off(frag) + offset); + iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, + slen); + + ret =3D INDIRECT_CALL_2(sendmsg, sendmsg_locked, + sendmsg_unlocked, sk, &msg); if (ret <=3D 0) goto error; =20 @@ -3107,16 +3115,14 @@ static int __skb_send_sock(struct sock *sk, struct = sk_buff *skb, int offset, int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset, int len) { - return __skb_send_sock(sk, skb, offset, len, kernel_sendmsg_locked, - kernel_sendpage_locked); + return __skb_send_sock(sk, skb, offset, len, sendmsg_locked); } EXPORT_SYMBOL_GPL(skb_send_sock_locked); =20 /* Send skb data on a socket. Socket must be unlocked. */ int skb_send_sock(struct sock *sk, struct sk_buff *skb, int offset, int le= n) { - return __skb_send_sock(sk, skb, offset, len, sendmsg_unlocked, - sendpage_unlocked); + return __skb_send_sock(sk, skb, offset, len, sendmsg_unlocked); } =20 /**