From patchwork Tue Jul 19 17:02:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 12922799 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0D015C433EF for ; Tue, 19 Jul 2022 17:27:29 +0000 (UTC) Received: from localhost ([::1]:35058 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oDr0K-0006z7-61 for qemu-devel@archiver.kernel.org; Tue, 19 Jul 2022 13:27:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43128) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oDqd1-0007GI-5G for qemu-devel@nongnu.org; Tue, 19 Jul 2022 13:03:23 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:45635) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oDqcy-00031z-H6 for qemu-devel@nongnu.org; Tue, 19 Jul 2022 13:03:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658250199; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jT5SCI9yceEEWoJ6eZlL1Ya13QG2Pfnwc9vFeYp3jBA=; b=SnsiyTGVsL9GPg9aU0Fhds6KLrHKVpgNHbmDHo/bS6Oli697FDA3j5+sZQKTbAbpRttsUF MrujgwsgHxj7O/KyIc43H2A8vxJUlDfx+axGHZdYiOz1auZH3smXJnU2oJ5iK40dxWDoaM DFlHp4oRu6f9PwF01S8Ec22fL/4Vm7A= 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-635-yAdT5zA5Nsa6M-gSlxSyJg-1; Tue, 19 Jul 2022 13:03:06 -0400 X-MC-Unique: yAdT5zA5Nsa6M-gSlxSyJg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id A2F3B3C10156; Tue, 19 Jul 2022 17:02:56 +0000 (UTC) Received: from dgilbert-t580.localhost (unknown [10.33.36.162]) by smtp.corp.redhat.com (Postfix) with ESMTP id ACD4440CF8E5; Tue, 19 Jul 2022 17:02:55 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, leobras@redhat.com, quintela@redhat.com, berrange@redhat.com, peterx@redhat.com, iii@linux.ibm.com, huangy81@chinatelecom.cn Subject: [PULL 25/29] QIOChannelSocket: Fix zero-copy flush returning code 1 when nothing sent Date: Tue, 19 Jul 2022 18:02:17 +0100 Message-Id: <20220719170221.576190-26-dgilbert@redhat.com> In-Reply-To: <20220719170221.576190-1-dgilbert@redhat.com> References: <20220719170221.576190-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Received-SPF: pass client-ip=170.10.129.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Leonardo Bras If flush is called when no buffer was sent with MSG_ZEROCOPY, it currently returns 1. This return code should be used only when Linux fails to use MSG_ZEROCOPY on a lot of sendmsg(). Fix this by returning early from flush if no sendmsg(...,MSG_ZEROCOPY) was attempted. Fixes: 2bc58ffc2926 ("QIOChannelSocket: Implement io_writev zero copy flag & io_flush for CONFIG_LINUX") Signed-off-by: Leonardo Bras Reviewed-by: Daniel P. Berrangé Acked-by: Daniel P. Berrangé Reviewed-by: Juan Quintela Reviewed-by: Peter Xu Message-Id: <20220711211112.18951-2-leobras@redhat.com> Signed-off-by: Dr. David Alan Gilbert --- io/channel-socket.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/io/channel-socket.c b/io/channel-socket.c index 4466bb1cd4..74a936cc1f 100644 --- a/io/channel-socket.c +++ b/io/channel-socket.c @@ -716,12 +716,18 @@ static int qio_channel_socket_flush(QIOChannel *ioc, struct cmsghdr *cm; char control[CMSG_SPACE(sizeof(*serr))]; int received; - int ret = 1; + int ret; + + if (sioc->zero_copy_queued == sioc->zero_copy_sent) { + return 0; + } msg.msg_control = control; msg.msg_controllen = sizeof(control); memset(control, 0, sizeof(control)); + ret = 1; + while (sioc->zero_copy_sent < sioc->zero_copy_queued) { received = recvmsg(sioc->fd, &msg, MSG_ERRQUEUE); if (received < 0) {