From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by dpdk.org (Postfix) with ESMTP id 94CA99621 for ; Mon, 20 Jun 2016 08:27:50 +0200 (CEST) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga104.fm.intel.com with ESMTP; 19 Jun 2016 23:27:50 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,496,1459839600"; d="scan'208";a="1005659751" Received: from yliu-dev.sh.intel.com (HELO yliu-dev) ([10.239.67.162]) by fmsmga002.fm.intel.com with ESMTP; 19 Jun 2016 23:26:17 -0700 Date: Mon, 20 Jun 2016 14:27:10 +0800 From: Yuanhan Liu To: Huawei Xie Cc: dev@dpdk.org, yuanhan.liu@intel.com, thomas.monjalon@6wind.com, mst@redhat.com, jianfeng.tan@intel.com, stephen@networkplumber.org, konstantin.ananyev@intel.com, bruce.richardson@intel.com Message-ID: <20160620062710.GE23111@yliu-dev.sh.intel.com> References: <1466015437-36809-1-git-send-email-huawei.xie@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1466015437-36809-1-git-send-email-huawei.xie@intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Subject: Re: [dpdk-dev] [PATCH] virtio: fix idx in used ring retrieved only once X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Jun 2016 06:27:51 -0000 On Thu, Jun 16, 2016 at 02:30:37AM +0800, Huawei Xie wrote: > - while (vq->vq_used_cons_idx != vq->vq_ring.used->idx) { > + while (VIRTQUEUE_NUSED(vq)) { > uint32_t idx, desc_idx, used_idx; > struct vring_used_elem *uep; > > diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h > index 447760a..fcecc16 100644 > --- a/drivers/net/virtio/virtio_ring.h > +++ b/drivers/net/virtio/virtio_ring.h > @@ -79,7 +79,7 @@ struct vring_used_elem { > > struct vring_used { > uint16_t flags; > - uint16_t idx; > + volatile uint16_t idx; > struct vring_used_elem ring[0]; > }; > > diff --git a/drivers/net/virtio/virtio_rxtx_simple.c b/drivers/net/virtio/virtio_rxtx_simple.c > index 7b50119..a0ef8d2 100644 > --- a/drivers/net/virtio/virtio_rxtx_simple.c > +++ b/drivers/net/virtio/virtio_rxtx_simple.c > @@ -184,8 +184,7 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts, > if (unlikely(nb_pkts < RTE_VIRTIO_DESC_PER_LOOP)) > return 0; > > - nb_used = *(volatile uint16_t *)&vq->vq_ring.used->idx - > - vq->vq_used_cons_idx; > + nb_used = vq->vq_ring.used->idx - vq->vq_used_cons_idx; How about replacing it with VIRTQUEUE_NUSED here? --yliu