From patchwork Wed Mar 29 14:13:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13192576 X-Patchwork-Delegate: kuba@kernel.org 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 27AB5C77B6C for ; Wed, 29 Mar 2023 14:18:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231169AbjC2OSK (ORCPT ); Wed, 29 Mar 2023 10:18:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230488AbjC2ORS (ORCPT ); Wed, 29 Mar 2023 10:17:18 -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 9529C5264 for ; Wed, 29 Mar 2023 07:15:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680099269; 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=4TWX2aSvGOZ9Qof5Bdvg67w1lje6zmFD7Oc0vC/yB3w=; b=a9G+vdovvcQ4yj/mn4iy+Jan/3nSaGVNiLyGCz237oj7mbYZ6F6iDYuDLN/C1S9JQ+AZ8n 4xLZC5w7rcMIUOY8Lf4gGxYvnIpBw4S/NH9gqQxXstONw1gScyxpUc0uk8leRWXNtUGn3e kiMMfF2e4/hHyHGoElDVGkry8szRAA4= 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-106-aG1NERqFMhu5XfuNhb_KOw-1; Wed, 29 Mar 2023 10:14:25 -0400 X-MC-Unique: aG1NERqFMhu5XfuNhb_KOw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E1811811E7C; Wed, 29 Mar 2023 14:14:24 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id 082972027040; Wed, 29 Mar 2023 14:14:22 +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 09/48] tcp: Make sendmsg(MSG_SPLICE_PAGES) copy unspliceable data Date: Wed, 29 Mar 2023 15:13:15 +0100 Message-Id: <20230329141354.516864-10-dhowells@redhat.com> In-Reply-To: <20230329141354.516864-1-dhowells@redhat.com> References: <20230329141354.516864-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC If sendmsg() with MSG_SPLICE_PAGES encounters a page that shouldn't be spliced - a slab page, for instance, or one with a zero count - make tcp_sendmsg() copy it. Signed-off-by: David Howells cc: Eric Dumazet cc: "David S. Miller" cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Matthew Wilcox cc: netdev@vger.kernel.org --- net/ipv4/tcp.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 910b327c236e..6ef0518eb706 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1417,10 +1417,10 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) goto do_error; copy = err; } else if (zc == 2) { - /* Splice in data. */ + /* Splice in data if we can; copy if we can't. */ struct page *page = NULL, **pages = &page; size_t off = 0, part; - bool can_coalesce; + bool can_coalesce, put = false; int i = skb_shinfo(skb)->nr_frags; copy = iov_iter_extract_pages(&msg->msg_iter, &pages, @@ -1447,12 +1447,34 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) goto wait_for_space; copy = part; + if (!sendpage_ok(page)) { + const void *p = kmap_local_page(page); + void *q; + + q = page_frag_memdup(NULL, p + off, copy, + sk->sk_allocation, ULONG_MAX); + kunmap_local(p); + if (!q) { + iov_iter_revert(&msg->msg_iter, copy); + err = copy ?: -ENOMEM; + goto do_error; + } + page = virt_to_page(q); + off = offset_in_page(q); + put = true; + can_coalesce = false; + } + if (can_coalesce) { skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); } else { - get_page(page); + if (!put) + get_page(page); + put = false; skb_fill_page_desc_noacc(skb, i, page, off, copy); } + if (put) + put_page(page); page = NULL; if (!(flags & MSG_NO_SHARED_FRAGS))