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[2620:137:e000::1:20]) by mx.google.com with ESMTP id lv21-20020a170906bc9500b00947797f2840si1078731ejb.320.2023.03.31.09.35.52; Fri, 31 Mar 2023 09:36:16 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=DNrYTrhc; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233153AbjCaQQs (ORCPT + 99 others); Fri, 31 Mar 2023 12:16:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42198 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233391AbjCaQQa (ORCPT ); Fri, 31 Mar 2023 12:16:30 -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 DA8C42658C for ; Fri, 31 Mar 2023 09:11:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680279057; 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=KbTdePCQuY00Eh43/mGhCoyrcL0EDX5k9L0XaPYIsA0=; b=DNrYTrhcDpY+5WJqIl+waxiTz4PVv9bTa4MGMutlH6CHO6bxVH8cJuEPnDRMaLUmseHKM7 A3vwdzrc145tImcq6UJP4biY8cP6JfS+2GVhEMLjwt+SeT1I+o3johwwKvolHrlVagztYY XUl2hzO4a4SBgvO0cXmLGcu3oPCmHmk= 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-615--qgn__EoP-eE5uusdvkQ2A-1; Fri, 31 Mar 2023 12:10:54 -0400 X-MC-Unique: -qgn__EoP-eE5uusdvkQ2A-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 7FD543802AC1; Fri, 31 Mar 2023 16:10:52 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id 63D4851FF; Fri, 31 Mar 2023 16:10:50 +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, Tom Herbert , Tom Herbert Subject: [PATCH v3 33/55] kcm: Support MSG_SPLICE_PAGES Date: Fri, 31 Mar 2023 17:08:52 +0100 Message-Id: <20230331160914.1608208-34-dhowells@redhat.com> In-Reply-To: <20230331160914.1608208-1-dhowells@redhat.com> References: <20230331160914.1608208-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 X-Spam-Status: No, score=-0.2 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1761901885533544298?= X-GMAIL-MSGID: =?utf-8?q?1761901885533544298?= Make AF_KCM sendmsg() support MSG_SPLICE_PAGES. This causes pages to be spliced from the source iterator if possible and copied 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: Tom Herbert cc: Tom Herbert cc: Jakub Kicinski cc: Eric Dumazet cc: "David S. Miller" cc: Paolo Abeni cc: Jens Axboe cc: Matthew Wilcox cc: netdev@vger.kernel.org --- net/kcm/kcmsock.c | 89 ++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 72 insertions(+), 17 deletions(-) diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c index cfe828bd7fc6..0a3f79d81595 100644 --- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -989,29 +989,84 @@ static int kcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) merge = false; } - copy = min_t(int, msg_data_left(msg), - pfrag->size - pfrag->offset); + if (msg->msg_flags & MSG_SPLICE_PAGES) { + struct page *page = NULL, **pages = &page; + size_t off; + bool put = false; + + err = iov_iter_extract_pages(&msg->msg_iter, &pages, + INT_MAX, 1, 0, &off); + if (err <= 0) { + err = err ?: -EIO; + goto out_error; + } + copy = err; - if (!sk_wmem_schedule(sk, copy)) - goto wait_for_memory; + if (skb_can_coalesce(skb, i, page, off)) { + skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); + goto coalesced; + } - err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb, - pfrag->page, - pfrag->offset, - copy); - if (err) - goto out_error; + if (!sk_wmem_schedule(sk, copy)) { + iov_iter_revert(&msg->msg_iter, copy); + goto wait_for_memory; + } + + if (!sendpage_ok(page)) { + const void *p = kmap_local_page(page); + void *q; - /* Update the skb. */ - if (merge) { - skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); + 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 = -ENOMEM; + goto out_error; + } + page = virt_to_page(q); + off = offset_in_page(q); + put = true; + } + + skb_fill_page_desc_noacc(skb, i, page, off, copy); + if (put) + put_page(page); +coalesced: + skb_shinfo(skb)->flags |= SKBFL_SHARED_FRAG; + skb->len += copy; + skb->data_len += copy; + skb->truesize += copy; + sk->sk_wmem_queued += copy; + sk_mem_charge(sk, copy); + + if (head != skb) + head->truesize += copy; } else { - skb_fill_page_desc(skb, i, pfrag->page, - pfrag->offset, copy); - get_page(pfrag->page); + copy = min_t(int, msg_data_left(msg), + pfrag->size - pfrag->offset); + if (!sk_wmem_schedule(sk, copy)) + goto wait_for_memory; + + err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb, + pfrag->page, + pfrag->offset, + copy); + if (err) + goto out_error; + + /* Update the skb. */ + if (merge) { + skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); + } else { + skb_fill_page_desc(skb, i, pfrag->page, + pfrag->offset, copy); + get_page(pfrag->page); + } + + pfrag->offset += copy; } - pfrag->offset += copy; copied += copy; if (head != skb) { head->len += copy;