On Mon, Jun 28, 2010 at 10:11:43AM -0700, Sridhar Samudrala wrote: > On Sun, 2010-06-27 at 11:59 +0300, Michael S. Tsirkin wrote: > > When ring parsing fails, we currently handle this > > as ring empty condition. This means that we enable > > kicks and recheck ring empty: if this not empty, > > we re-start polling which of course will fail again. > > > > Instead, let's return a negative error code and stop polling. > > One minor comment on error return below. With that change, > > Acked-by: Sridhar Samudrala <[email protected]>
Right. In fact, we don't really use the return code, and the generated binary is smaller if we return -EINVAL always. So that's what I'll do. > > > > Signed-off-by: Michael S. Tsirkin <[email protected]> > > --- > > > > Dave, I'm sending this out so it can get reviewed. > > I'll put this on my vhost tree > > so no need for you to pick this patch directly. > > > > drivers/vhost/net.c | 12 ++++++++++-- > > drivers/vhost/vhost.c | 33 +++++++++++++++++---------------- > > drivers/vhost/vhost.h | 8 ++++---- > > 3 files changed, 31 insertions(+), 22 deletions(-) > > > > 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; > > This should be -EINVAL > > } > > > > /* 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); _______________________________________________ Virtualization mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/virtualization
