From patchwork Sun Jun 27 08:59:07 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 108247 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.4/8.14.3) with ESMTP id o5R94sh3000773 for ; Sun, 27 Jun 2010 09:04:54 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753520Ab0F0JEi (ORCPT ); Sun, 27 Jun 2010 05:04:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:24217 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752701Ab0F0JEh (ORCPT ); Sun, 27 Jun 2010 05:04:37 -0400 Received: from int-mx03.intmail.prod.int.phx2.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.16]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o5R94CBX006242 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sun, 27 Jun 2010 05:04:12 -0400 Received: from redhat.com (vpn-6-62.tlv.redhat.com [10.35.6.62]) by int-mx03.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with SMTP id o5R946dv007335; Sun, 27 Jun 2010 05:04:06 -0400 Date: Sun, 27 Jun 2010 11:59:07 +0300 From: "Michael S. Tsirkin" To: Sridhar Samudrala , Arnd Bergmann , "Paul E. McKenney" , Juan Quintela , Rusty Russell , Jes.Sorensen@redhat.com, kraxel@redhat.com, Takuya Yoshikawa , kvm@vger.kernel.org, virtualization@lists.osdl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] vhost: break out of polling loop on error Message-ID: <20100627085907.GA8588@redhat.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.19 (2009-01-05) X-Scanned-By: MIMEDefang 2.67 on 10.5.11.16 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Sun, 27 Jun 2010 09:04:55 +0000 (UTC) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 0f41c91..54096ee 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -98,7 +98,8 @@ static void tx_poll_start(struct vhost_net *net, struct socket *sock) static void handle_tx(struct vhost_net *net) { struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX]; - unsigned head, out, in, s; + unsigned out, in, s; + int head; struct msghdr msg = { .msg_name = NULL, .msg_namelen = 0, @@ -135,6 +136,9 @@ static void handle_tx(struct vhost_net *net) ARRAY_SIZE(vq->iov), &out, &in, NULL, NULL); + /* On error, stop handling until the next kick. */ + if (head < 0) + break; /* Nothing new? Wait for eventfd to tell us they refilled. */ if (head == vq->num) { wmem = atomic_read(&sock->sk->sk_wmem_alloc); @@ -192,7 +196,8 @@ static void handle_tx(struct vhost_net *net) static void handle_rx(struct vhost_net *net) { struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX]; - unsigned head, out, in, log, s; + unsigned out, in, log, s; + int head; struct vhost_log *vq_log; struct msghdr msg = { .msg_name = NULL, @@ -228,6 +233,9 @@ static void handle_rx(struct vhost_net *net) ARRAY_SIZE(vq->iov), &out, &in, vq_log, &log); + /* On error, stop handling until the next kick. */ + if (head < 0) + break; /* OK, now we need to know about added descriptors. */ if (head == vq->num) { if (unlikely(vhost_enable_notify(vq))) { diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 3b83382..5ccd384 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -873,12 +873,13 @@ static unsigned get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq, * number of output then some number of input descriptors, it's actually two * iovecs, but we pack them into one and note how many of each there were. * - * This function returns the descriptor number found, or vq->num (which - * is never a valid descriptor number) if none was found. */ -unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, - struct iovec iov[], unsigned int iov_size, - unsigned int *out_num, unsigned int *in_num, - struct vhost_log *log, unsigned int *log_num) + * This function returns the descriptor number found, or vq->num (which is + * never a valid descriptor number) if none was found. A negative code is + * returned on error. */ +int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, + struct iovec iov[], unsigned int iov_size, + unsigned int *out_num, unsigned int *in_num, + struct vhost_log *log, unsigned int *log_num) { struct vring_desc desc; unsigned int i, head, found = 0; @@ -890,13 +891,13 @@ unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, if (get_user(vq->avail_idx, &vq->avail->idx)) { vq_err(vq, "Failed to access avail idx at %p\n", &vq->avail->idx); - return vq->num; + return -EFAULT; } if ((u16)(vq->avail_idx - last_avail_idx) > vq->num) { vq_err(vq, "Guest moved used index from %u to %u", last_avail_idx, vq->avail_idx); - return vq->num; + return -EFAULT; } /* If there's nothing new since last we looked, return invalid. */ @@ -912,14 +913,14 @@ unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, vq_err(vq, "Failed to read head: idx %d address %p\n", last_avail_idx, &vq->avail->ring[last_avail_idx % vq->num]); - return vq->num; + return -EFAULT; } /* If their number is silly, that's an error. */ if (head >= vq->num) { vq_err(vq, "Guest says index %u > %u is available", head, vq->num); - return vq->num; + return -EINVAL; } /* When we start there are none of either input nor output. */ @@ -933,19 +934,19 @@ unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, if (i >= vq->num) { vq_err(vq, "Desc index is %u > %u, head = %u", i, vq->num, head); - return vq->num; + return -EINVAL; } if (++found > vq->num) { vq_err(vq, "Loop detected: last one at %u " "vq size %u head %u\n", i, vq->num, head); - return vq->num; + return -EINVAL; } ret = copy_from_user(&desc, vq->desc + i, sizeof desc); if (ret) { vq_err(vq, "Failed to get descriptor: idx %d addr %p\n", i, vq->desc + i); - return vq->num; + return -EFAULT; } if (desc.flags & VRING_DESC_F_INDIRECT) { ret = get_indirect(dev, vq, iov, iov_size, @@ -954,7 +955,7 @@ unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, if (ret < 0) { vq_err(vq, "Failure detected " "in indirect descriptor at idx %d\n", i); - return vq->num; + return ret; } continue; } @@ -964,7 +965,7 @@ unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, if (ret < 0) { vq_err(vq, "Translation failure %d descriptor idx %d\n", ret, i); - return vq->num; + return ret; } if (desc.flags & VRING_DESC_F_WRITE) { /* If this is an input descriptor, @@ -981,7 +982,7 @@ unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, if (*in_num) { vq_err(vq, "Descriptor has out after in: " "idx %d\n", i); - return vq->num; + return -EINVAL; } *out_num += ret; } diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 44591ba..11ee13d 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -120,10 +120,10 @@ long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg); int vhost_vq_access_ok(struct vhost_virtqueue *vq); int vhost_log_access_ok(struct vhost_dev *); -unsigned vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *, - struct iovec iov[], unsigned int iov_count, - unsigned int *out_num, unsigned int *in_num, - struct vhost_log *log, unsigned int *log_num); +int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *, + struct iovec iov[], unsigned int iov_count, + unsigned int *out_num, unsigned int *in_num, + struct vhost_log *log, unsigned int *log_num); void vhost_discard_vq_desc(struct vhost_virtqueue *); int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);