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 87495C77B6E for ; Wed, 29 Mar 2023 14:18:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230083AbjC2OSA (ORCPT ); Wed, 29 Mar 2023 10:18:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230060AbjC2ORO (ORCPT ); Wed, 29 Mar 2023 10:17:14 -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 0757840EA for ; Wed, 29 Mar 2023 07:15:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680099297; 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=NG18J76VRrzhfHMvUgJjpISKtrp6GX9XUZPxH3Nxq0I=; b=BZBk9tbfGk1HZMKZ9Id9OSBeICMwdfL6+Xv9C1aqbVxcgFUcLcAbcZc947vaaHbjrI99/o p+flz5kt+zgG/u+vfilCKg3iW0r4tG+XoKyBjCVShF/EdDQjJkG8bon7sGgig0xF/Z4put PjesbE/DygjTWvNNIA3LV7eyIMEJ2Mo= 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-310-xuaB0LLNMnyvhGqA--dfEQ-1; Wed, 29 Mar 2023 10:14:52 -0400 X-MC-Unique: xuaB0LLNMnyvhGqA--dfEQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9B50B1C0758A; Wed, 29 Mar 2023 14:14:51 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id BA9AC2166B33; Wed, 29 Mar 2023 14:14:49 +0000 (UTC) From: David Howells To: Matthew Wilcox , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: David Howells , Al Viro , Christoph Hellwig , Jens Axboe , Jeff Layton , Christian Brauner , Chuck Lever III , Linus Torvalds , netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v2 19/48] af_unix: Support MSG_SPLICE_PAGES Date: Wed, 29 Mar 2023 15:13:25 +0100 Message-Id: <20230329141354.516864-20-dhowells@redhat.com> In-Reply-To: <20230329141354.516864-1-dhowells@redhat.com> References: <20230329141354.516864-1-dhowells@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Make AF_UNIX sendmsg() support MSG_SPLICE_PAGES, splicing in pages from the source iterator if given and if ITER_BVEC and copying the data in otherwise. This allows ->sendpage() to be replaced by something that can handle multiple multipage folios in a single transaction. 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 --- net/unix/af_unix.c | 93 ++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 77 insertions(+), 16 deletions(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 347122c3575e..84a0d97f1aa4 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2151,6 +2151,53 @@ static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other } #endif +/* + * Extract pages from an iterator and add them to the socket buffer. + */ +static ssize_t unix_extract_bvec_to_skb(struct sk_buff *skb, + struct iov_iter *iter, ssize_t maxsize) +{ + struct page *pages[8], **ppages = pages; + unsigned int i, nr; + ssize_t ret = 0; + + while (iter->count > 0) { + size_t off, len; + + nr = min(MAX_SKB_FRAGS - skb_shinfo(skb)->nr_frags, + ARRAY_SIZE(pages)); + if (nr == 0) + break; + + len = iov_iter_extract_pages(iter, &ppages, maxsize, nr, 0, &off); + if (len <= 0) { + if (!ret) + ret = len ?: -EIO; + break; + } + + i = 0; + do { + size_t part = min(PAGE_SIZE - off, len); + + if (skb_append_pagefrags(skb, pages[i++], off, part) < 0) { + if (!ret) + ret = -EMSGSIZE; + goto out; + } + off = 0; + ret += part; + maxsize -= part; + len -= part; + } while (len > 0); + if (maxsize <= 0) + break; + } + +out: + return ret; +} + static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) { @@ -2194,19 +2241,25 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, while (sent < len) { size = len - sent; - /* Keep two messages in the pipe so it schedules better */ - size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64); + if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) { + skb = sock_alloc_send_pskb(sk, 0, 0, + msg->msg_flags & MSG_DONTWAIT, + &err, 0); + } else { + /* Keep two messages in the pipe so it schedules better */ + size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64); - /* allow fallback to order-0 allocations */ - size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ); + /* allow fallback to order-0 allocations */ + size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ); - data_len = max_t(int, 0, size - SKB_MAX_HEAD(0)); + data_len = max_t(int, 0, size - SKB_MAX_HEAD(0)); - data_len = min_t(size_t, size, PAGE_ALIGN(data_len)); + data_len = min_t(size_t, size, PAGE_ALIGN(data_len)); - skb = sock_alloc_send_pskb(sk, size - data_len, data_len, - msg->msg_flags & MSG_DONTWAIT, &err, - get_order(UNIX_SKB_FRAGS_SZ)); + skb = sock_alloc_send_pskb(sk, size - data_len, data_len, + msg->msg_flags & MSG_DONTWAIT, &err, + get_order(UNIX_SKB_FRAGS_SZ)); + } if (!skb) goto out_err; @@ -2218,13 +2271,21 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, } fds_sent = true; - skb_put(skb, size - data_len); - skb->data_len = data_len; - skb->len = size; - err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size); - if (err) { - kfree_skb(skb); - goto out_err; + if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) { + size = unix_extract_bvec_to_skb(skb, &msg->msg_iter, size); + skb->data_len += size; + skb->len += size; + skb->truesize += size; + refcount_add(size, &sk->sk_wmem_alloc); + } else { + skb_put(skb, size - data_len); + skb->data_len = data_len; + skb->len = size; + err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size); + if (err) { + kfree_skb(skb); + goto out_err; + } } unix_state_lock(other);