From patchwork Tue Jan 21 12:23:51 2020 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: 11343805 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 21C3B1398 for ; Tue, 21 Jan 2020 13:08:16 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id ECE1120882 for ; Tue, 21 Jan 2020 13:08:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Byg0lRMu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ECE1120882 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:53560 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ittGQ-0007qY-JE for patchwork-qemu-devel@patchwork.kernel.org; Tue, 21 Jan 2020 08:08:14 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:52331) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1itsg6-0002DH-Vs for qemu-devel@nongnu.org; Tue, 21 Jan 2020 07:30:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1itsg3-0004DY-21 for qemu-devel@nongnu.org; Tue, 21 Jan 2020 07:30:42 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:37691 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1itsg2-0004DO-UI for qemu-devel@nongnu.org; Tue, 21 Jan 2020 07:30:39 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579609838; 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: in-reply-to:in-reply-to:references:references; bh=saxJp3gmNUaoX28RCBi9UCp8pebRIGJmfaOnCtZ8AMk=; b=Byg0lRMu7EWjzreaMU6Um4xncA+QgXI7ys9BNuMoFO/wdjf+/3WEnVSdbrSJxgzPz9dn4G Kr4qaTcoFjmrZJuh61LB4QqZKMX7NbraA5rNppZaq50n6UTvVVne3TkRgxa8yPAK8NsnH9 VDgU99L/2AiAJPbde7GTW1IHpgBytGI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-139-yfCZIGSfPBGcjPx1gKiTBw-1; Tue, 21 Jan 2020 07:30:35 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 027CC802B94; Tue, 21 Jan 2020 12:30:34 +0000 (UTC) Received: from dgilbert-t580.localhost (unknown [10.36.118.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8B36D60BE0; Tue, 21 Jan 2020 12:30:29 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com, berrange@redhat.com, slp@redhat.com, philmd@redhat.com Subject: [PATCH v2 067/109] contrib/libvhost-user: Protect slave fd with mutex Date: Tue, 21 Jan 2020 12:23:51 +0000 Message-Id: <20200121122433.50803-68-dgilbert@redhat.com> In-Reply-To: <20200121122433.50803-1-dgilbert@redhat.com> References: <20200121122433.50803-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: yfCZIGSfPBGcjPx1gKiTBw-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: m.mizuma@jp.fujitsu.com, misono.tomohiro@jp.fujitsu.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: "Dr. David Alan Gilbert" In future patches we'll be performing commands on the slave-fd driven by commands on queues, since those queues will be driven by individual threads we need to make sure they don't attempt to use the slave-fd for multiple commands in parallel. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Daniel P. Berrangé --- contrib/libvhost-user/libvhost-user.c | 24 ++++++++++++++++++++---- contrib/libvhost-user/libvhost-user.h | 3 +++ 2 files changed, 23 insertions(+), 4 deletions(-) diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c index ec27b78ff1..63e41062a4 100644 --- a/contrib/libvhost-user/libvhost-user.c +++ b/contrib/libvhost-user/libvhost-user.c @@ -392,26 +392,37 @@ vu_send_reply(VuDev *dev, int conn_fd, VhostUserMsg *vmsg) return vu_message_write(dev, conn_fd, vmsg); } +/* + * Processes a reply on the slave channel. + * Entered with slave_mutex held and releases it before exit. + * Returns true on success. + */ static bool vu_process_message_reply(VuDev *dev, const VhostUserMsg *vmsg) { VhostUserMsg msg_reply; + bool result = false; if ((vmsg->flags & VHOST_USER_NEED_REPLY_MASK) == 0) { - return true; + result = true; + goto out; } if (!vu_message_read(dev, dev->slave_fd, &msg_reply)) { - return false; + goto out; } if (msg_reply.request != vmsg->request) { DPRINT("Received unexpected msg type. Expected %d received %d", vmsg->request, msg_reply.request); - return false; + goto out; } - return msg_reply.payload.u64 == 0; + result = msg_reply.payload.u64 == 0; + +out: + pthread_mutex_unlock(&dev->slave_mutex); + return result; } /* Kick the log_call_fd if required. */ @@ -1105,10 +1116,13 @@ bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq, int fd, return false; } + pthread_mutex_lock(&dev->slave_mutex); if (!vu_message_write(dev, dev->slave_fd, &vmsg)) { + pthread_mutex_unlock(&dev->slave_mutex); return false; } + /* Also unlocks the slave_mutex */ return vu_process_message_reply(dev, &vmsg); } @@ -1628,6 +1642,7 @@ vu_deinit(VuDev *dev) close(dev->slave_fd); dev->slave_fd = -1; } + pthread_mutex_destroy(&dev->slave_mutex); if (dev->sock != -1) { close(dev->sock); @@ -1663,6 +1678,7 @@ vu_init(VuDev *dev, dev->remove_watch = remove_watch; dev->iface = iface; dev->log_call_fd = -1; + pthread_mutex_init(&dev->slave_mutex, NULL); dev->slave_fd = -1; dev->max_queues = max_queues; diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h index 46b600799b..1844b6f8d4 100644 --- a/contrib/libvhost-user/libvhost-user.h +++ b/contrib/libvhost-user/libvhost-user.h @@ -19,6 +19,7 @@ #include #include #include +#include #include "standard-headers/linux/virtio_ring.h" /* Based on qemu/hw/virtio/vhost-user.c */ @@ -355,6 +356,8 @@ struct VuDev { VuVirtq *vq; VuDevInflightInfo inflight_info; int log_call_fd; + /* Must be held while using slave_fd */ + pthread_mutex_t slave_mutex; int slave_fd; uint64_t log_size; uint8_t *log_table;