From 63350994825046216104c9c4c99db9e7a2715a97 Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Wed, 22 Oct 2014 14:08:53 +0100 Subject: [PATCH 12/14] xen-netback: make feature-rx-notify mandatory Origin: https://git.kernel.org/linus/bc96f648df1bbc2729abbb84513cf4f64273a1f1 Frontends that do not provide feature-rx-notify may stall because netback depends on the notification from frontend to wake the guest Rx thread (even if can_queue is false). This could be fixed but feature-rx-notify was introduced in 2006 and I am not aware of any frontends that do not implement this. Signed-off-by: David Vrabel Acked-by: Wei Liu Signed-off-by: David S. Miller (cherry picked from commit bc96f648df1bbc2729abbb84513cf4f64273a1f1) --- drivers/net/xen-netback/common.h | 5 ----- drivers/net/xen-netback/interface.c | 12 +----------- drivers/net/xen-netback/xenbus.c | 13 ++++--------- 3 files changed, 5 insertions(+), 25 deletions(-) diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h index d4eb8d2..93ca77c 100644 --- a/drivers/net/xen-netback/common.h +++ b/drivers/net/xen-netback/common.h @@ -228,9 +228,6 @@ struct xenvif { u8 ip_csum:1; u8 ipv6_csum:1; - /* Internal feature information. */ - u8 can_queue:1; /* can queue packets for receiver? */ - /* Is this interface disabled? True when backend discovers * frontend is rogue. */ @@ -272,8 +269,6 @@ void xenvif_xenbus_fini(void); int xenvif_schedulable(struct xenvif *vif); -int xenvif_must_stop_queue(struct xenvif_queue *queue); - int xenvif_queue_stopped(struct xenvif_queue *queue); void xenvif_wake_queue(struct xenvif_queue *queue); diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index 18cdc81..6879251 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -60,16 +60,6 @@ void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue) atomic_dec(&queue->inflight_packets); } -static inline void xenvif_stop_queue(struct xenvif_queue *queue) -{ - struct net_device *dev = queue->vif->dev; - - if (!queue->vif->can_queue) - return; - - netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id)); -} - int xenvif_schedulable(struct xenvif *vif) { return netif_running(vif->dev) && @@ -209,7 +199,7 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev) if (!xenvif_rx_ring_slots_available(queue, min_slots_needed)) { queue->rx_stalled.function = xenvif_rx_stalled; queue->rx_stalled.data = (unsigned long)queue; - xenvif_stop_queue(queue); + netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id)); mod_timer(&queue->rx_stalled, jiffies + rx_drain_timeout_jiffies); } diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c index 9c47b89..5e5cca1 100644 --- a/drivers/net/xen-netback/xenbus.c +++ b/drivers/net/xen-netback/xenbus.c @@ -873,15 +873,10 @@ static int read_xenbus_vif_flags(struct backend_info *be) if (!rx_copy) return -EOPNOTSUPP; - if (vif->dev->tx_queue_len != 0) { - if (xenbus_scanf(XBT_NIL, dev->otherend, - "feature-rx-notify", "%d", &val) < 0) - val = 0; - if (val) - vif->can_queue = 1; - else - /* Must be non-zero for pfifo_fast to work. */ - vif->dev->tx_queue_len = 1; + if (xenbus_scanf(XBT_NIL, dev->otherend, + "feature-rx-notify", "%d", &val) < 0 || val == 0) { + xenbus_dev_fatal(dev, -EINVAL, "feature-rx-notify is mandatory"); + return -EINVAL; } if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg", -- 1.7.10.4