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Thu, 23 Jan 2020 16:48:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579798088; 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=e74Ge0Ww7yZZA67xuglCD/tn2A4GJ0jR8Z8DEmaF9SQ=; b=RwGFtI5Ucn8CAocm3otN5mHMcprt5RHF85Rl8XSihrvMQGPHpJsF18+iVhYGGmVY9aei/B vHjwddSBehzwvKwXAMsg/CANxvwUEOc0ev42zBIze+qbCxy+JRbv5iDnIsRiKfb0OhFVfT FJAh/b/PT0WRYBsvg7oozb0+5CItl60= From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com Subject: [PULL 066/108] contrib/libvhost-user: Protect slave fd with mutex Date: Thu, 23 Jan 2020 16:45:48 +0000 Message-Id: <20200123164630.91498-67-dgilbert@redhat.com> In-Reply-To: <20200123164630.91498-1-dgilbert@redhat.com> References: <20200123164630.91498-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-MC-Unique: hwASJZ4ANoCnM53LfsY8OQ-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] 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: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" 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. Berrang=C3=A9 Signed-off-by: Dr. David Alan Gilbert --- 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); } =20 +/* + * 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 =3D false; =20 if ((vmsg->flags & VHOST_USER_NEED_REPLY_MASK) =3D=3D 0) { - return true; + result =3D true; + goto out; } =20 if (!vu_message_read(dev, dev->slave_fd, &msg_reply)) { - return false; + goto out; } =20 if (msg_reply.request !=3D vmsg->request) { DPRINT("Received unexpected msg type. Expected %d received %d", vmsg->request, msg_reply.request); - return false; + goto out; } =20 - return msg_reply.payload.u64 =3D=3D 0; + result =3D msg_reply.payload.u64 =3D=3D 0; + +out: + pthread_mutex_unlock(&dev->slave_mutex); + return result; } =20 /* 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; } =20 + pthread_mutex_lock(&dev->slave_mutex); if (!vu_message_write(dev, dev->slave_fd, &vmsg)) { + pthread_mutex_unlock(&dev->slave_mutex); return false; } =20 + /* Also unlocks the slave_mutex */ return vu_process_message_reply(dev, &vmsg); } =20 @@ -1628,6 +1642,7 @@ vu_deinit(VuDev *dev) close(dev->slave_fd); dev->slave_fd =3D -1; } + pthread_mutex_destroy(&dev->slave_mutex); =20 if (dev->sock !=3D -1) { close(dev->sock); @@ -1663,6 +1678,7 @@ vu_init(VuDev *dev, dev->remove_watch =3D remove_watch; dev->iface =3D iface; dev->log_call_fd =3D -1; + pthread_mutex_init(&dev->slave_mutex, NULL); dev->slave_fd =3D -1; dev->max_queues =3D max_queues; =20 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" =20 /* 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; --=20 2.24.1