From patchwork Tue Jun 27 13:49:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13294527 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 BC939EB64D9 for ; Tue, 27 Jun 2023 13:50:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231265AbjF0Nuo (ORCPT ); Tue, 27 Jun 2023 09:50:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45866 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229652AbjF0Num (ORCPT ); Tue, 27 Jun 2023 09:50:42 -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 6AFD62963 for ; Tue, 27 Jun 2023 06:49:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1687873792; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=X74eAowOy71RsSeBwMWseaSFX+Cm6edwrYk6pqXDWys=; b=aA4w5dAgpByxhLIZhyine/dg/juGDqoJVPP019jwoqJgKISY9UW77M38hwWV4q8Cb2tUTF 5dnvFEmns7hiQm5EzM3bccLhxn/dGbTk8Hu+ppD1+3TgjtDQKYjG8JQ6fCAPkrf7NaX2o1 bB6jn++eMkq3crU9RsrAaukF12+LSbg= 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-441-sTOnqNXOOL-ZA_JCSExp0A-1; Tue, 27 Jun 2023 09:49:50 -0400 X-MC-Unique: sTOnqNXOOL-ZA_JCSExp0A-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 44F08380226D; Tue, 27 Jun 2023 13:49:50 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id A5164111F3B0; Tue, 27 Jun 2023 13:49:48 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells To: Ilya Dryomov , netdev@vger.kernel.org cc: dhowells@redhat.com, Xiubo Li , Jeff Layton , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jens Axboe , Matthew Wilcox , ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v3] libceph: Partially revert changes to support MSG_SPLICE_PAGES MIME-Version: 1.0 Content-ID: <3199651.1687873788.1@warthog.procyon.org.uk> Date: Tue, 27 Jun 2023 14:49:48 +0100 Message-ID: <3199652.1687873788@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org Fix the mishandling of MSG_DONTWAIT and also reinstates the per-page checking of the source pages (which might have come from a DIO write by userspace) by partially reverting the changes to support MSG_SPLICE_PAGES and doing things a little differently. In messenger_v1: (1) The ceph_tcp_sendpage() is resurrected and the callers reverted to use that. (2) The callers now pass MSG_MORE unconditionally. Previously, they were passing in MSG_MORE|MSG_SENDPAGE_NOTLAST and then degrading that to just MSG_MORE on the last call to ->sendpage(). (3) Make ceph_tcp_sendpage() a wrapper around sendmsg() rather than sendpage(), setting MSG_SPLICE_PAGES if sendpage_ok() returns true on the page. In messenger_v2: (4) Bring back do_try_sendpage() and make the callers use that. (5) Make do_try_sendpage() use sendmsg() for both cases and set MSG_SPLICE_PAGES if sendpage_ok() is set. Fixes: 40a8c17aa770 ("ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage") Fixes: fa094ccae1e7 ("ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage()") Reported-by: Ilya Dryomov Link: https://lore.kernel.org/r/CAOi1vP9vjLfk3W+AJFeexC93jqPaPUn2dD_4NrzxwoZTbYfOnw@mail.gmail.com/ Link: https://lore.kernel.org/r/CAOi1vP_Bn918j24S94MuGyn+Gxk212btw7yWeDrRcW1U8pc_BA@mail.gmail.com/ Signed-off-by: David Howells cc: Ilya Dryomov cc: Xiubo Li cc: Jeff Layton cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Matthew Wilcox cc: ceph-devel@vger.kernel.org cc: netdev@vger.kernel.org Link: https://lore.kernel.org/r/3101881.1687801973@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/3111635.1687813501@warthog.procyon.org.uk/ # v2 Reviewed-by: Ilya Dryomov --- Notes: ver #3) - Use ITER_SOURCE not ITER_DEST when sending. ver #2) - Removed mention of MSG_SENDPAGE_NOTLAST in comments. - Changed some refs to sendpage to MSG_SPLICE_PAGES in comments. - Init msg_iter in ceph_tcp_sendpage(). - Move setting of MSG_SPLICE_PAGES in do_try_sendpage() next to comment and adjust how it is cleared. net/ceph/messenger_v1.c | 58 ++++++++++++++++++++----------- net/ceph/messenger_v2.c | 88 ++++++++++++++++++++++++++++++++++++++---------- 2 files changed, 107 insertions(+), 39 deletions(-) diff --git a/net/ceph/messenger_v1.c b/net/ceph/messenger_v1.c index 814579f27f04..3d57bb48a2b4 100644 --- a/net/ceph/messenger_v1.c +++ b/net/ceph/messenger_v1.c @@ -74,6 +74,39 @@ static int ceph_tcp_sendmsg(struct socket *sock, struct kvec *iov, return r; } +/* + * @more: MSG_MORE or 0. + */ +static int ceph_tcp_sendpage(struct socket *sock, struct page *page, + int offset, size_t size, int more) +{ + struct msghdr msg = { + .msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL | more, + }; + struct bio_vec bvec; + int ret; + + /* + * MSG_SPLICE_PAGES cannot properly handle pages with page_count == 0, + * we need to fall back to sendmsg if that's the case. + * + * Same goes for slab pages: skb_can_coalesce() allows + * coalescing neighboring slab objects into a single frag which + * triggers one of hardened usercopy checks. + */ + if (sendpage_ok(page)) + msg.msg_flags |= MSG_SPLICE_PAGES; + + bvec_set_page(&bvec, page, size, offset); + iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, size); + + ret = sock_sendmsg(sock, &msg); + if (ret == -EAGAIN) + ret = 0; + + return ret; +} + static void con_out_kvec_reset(struct ceph_connection *con) { BUG_ON(con->v1.out_skip); @@ -450,10 +483,6 @@ static int write_partial_message_data(struct ceph_connection *con) */ crc = do_datacrc ? le32_to_cpu(msg->footer.data_crc) : 0; while (cursor->total_resid) { - struct bio_vec bvec; - struct msghdr msghdr = { - .msg_flags = MSG_SPLICE_PAGES, - }; struct page *page; size_t page_offset; size_t length; @@ -465,13 +494,8 @@ static int write_partial_message_data(struct ceph_connection *con) } page = ceph_msg_data_next(cursor, &page_offset, &length); - if (length != cursor->total_resid) - msghdr.msg_flags |= MSG_MORE; - - bvec_set_page(&bvec, page, length, page_offset); - iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, length); - - ret = sock_sendmsg(con->sock, &msghdr); + ret = ceph_tcp_sendpage(con->sock, page, page_offset, length, + MSG_MORE); if (ret <= 0) { if (do_datacrc) msg->footer.data_crc = cpu_to_le32(crc); @@ -501,22 +525,14 @@ static int write_partial_message_data(struct ceph_connection *con) */ static int write_partial_skip(struct ceph_connection *con) { - struct bio_vec bvec; - struct msghdr msghdr = { - .msg_flags = MSG_SPLICE_PAGES | MSG_MORE, - }; int ret; dout("%s %p %d left\n", __func__, con, con->v1.out_skip); while (con->v1.out_skip > 0) { size_t size = min(con->v1.out_skip, (int)PAGE_SIZE); - if (size == con->v1.out_skip) - msghdr.msg_flags &= ~MSG_MORE; - bvec_set_page(&bvec, ZERO_PAGE(0), size, 0); - iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, size); - - ret = sock_sendmsg(con->sock, &msghdr); + ret = ceph_tcp_sendpage(con->sock, ceph_zero_page, 0, size, + MSG_MORE); if (ret <= 0) goto out; con->v1.out_skip -= ret; diff --git a/net/ceph/messenger_v2.c b/net/ceph/messenger_v2.c index 87ac97073e75..1a888b86a494 100644 --- a/net/ceph/messenger_v2.c +++ b/net/ceph/messenger_v2.c @@ -117,38 +117,90 @@ static int ceph_tcp_recv(struct ceph_connection *con) return ret; } +static int do_sendmsg(struct socket *sock, struct iov_iter *it) +{ + struct msghdr msg = { .msg_flags = CEPH_MSG_FLAGS }; + int ret; + + msg.msg_iter = *it; + while (iov_iter_count(it)) { + ret = sock_sendmsg(sock, &msg); + if (ret <= 0) { + if (ret == -EAGAIN) + ret = 0; + return ret; + } + + iov_iter_advance(it, ret); + } + + WARN_ON(msg_data_left(&msg)); + return 1; +} + +static int do_try_sendpage(struct socket *sock, struct iov_iter *it) +{ + struct msghdr msg = { .msg_flags = CEPH_MSG_FLAGS }; + struct bio_vec bv; + int ret; + + if (WARN_ON(!iov_iter_is_bvec(it))) + return -EINVAL; + + while (iov_iter_count(it)) { + /* iov_iter_iovec() for ITER_BVEC */ + bvec_set_page(&bv, it->bvec->bv_page, + min(iov_iter_count(it), + it->bvec->bv_len - it->iov_offset), + it->bvec->bv_offset + it->iov_offset); + + /* + * MSG_SPLICE_PAGES cannot properly handle pages with + * page_count == 0, we need to fall back to sendmsg if + * that's the case. + * + * Same goes for slab pages: skb_can_coalesce() allows + * coalescing neighboring slab objects into a single frag + * which triggers one of hardened usercopy checks. + */ + if (sendpage_ok(bv.bv_page)) + msg.msg_flags |= MSG_SPLICE_PAGES; + else + msg.msg_flags &= ~MSG_SPLICE_PAGES; + + iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bv, 1, bv.bv_len); + ret = sock_sendmsg(sock, &msg); + if (ret <= 0) { + if (ret == -EAGAIN) + ret = 0; + return ret; + } + + iov_iter_advance(it, ret); + } + + return 1; +} + /* * Write as much as possible. The socket is expected to be corked, * so we don't bother with MSG_MORE here. * * Return: - * >0 - done, nothing (else) to write + * 1 - done, nothing (else) to write * 0 - socket is full, need to wait * <0 - error */ static int ceph_tcp_send(struct ceph_connection *con) { - struct msghdr msg = { - .msg_iter = con->v2.out_iter, - .msg_flags = CEPH_MSG_FLAGS, - }; int ret; - if (WARN_ON(!iov_iter_is_bvec(&con->v2.out_iter))) - return -EINVAL; - - if (con->v2.out_iter_sendpage) - msg.msg_flags |= MSG_SPLICE_PAGES; - dout("%s con %p have %zu try_sendpage %d\n", __func__, con, iov_iter_count(&con->v2.out_iter), con->v2.out_iter_sendpage); - - ret = sock_sendmsg(con->sock, &msg); - if (ret > 0) - iov_iter_advance(&con->v2.out_iter, ret); - else if (ret == -EAGAIN) - ret = 0; - + if (con->v2.out_iter_sendpage) + ret = do_try_sendpage(con->sock, &con->v2.out_iter); + else + ret = do_sendmsg(con->sock, &con->v2.out_iter); dout("%s con %p ret %d left %zu\n", __func__, con, ret, iov_iter_count(&con->v2.out_iter)); return ret;