Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  virtio: fix race in enable_cb
  virtio: Enable netpoll interface for netconsole logging
  virtio: handle > 2 billion page balloon targets
  virtio: Fix sysfs bits to have proper block symlink
  virtio: Use spin_lock_irqsave/restore for virtio-pci

6 files changed, 34 insertions, 14 deletions

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 3b1a68d6eddb..0cfbe8c594a5 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -238,6 +238,7 @@ static int virtblk_probe(struct virtio_device *vdev)
 	vblk->disk->first_minor = index_to_minor(index);
 	vblk->disk->private_data = vblk;
 	vblk->disk->fops = &virtblk_fops;
+	vblk->disk->driverfs_dev = &vdev->dev;
 	index++;
 
 	/* If barriers are supported, tell block layer that queue is ordered */
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 19fd4cb0ddf8..b58472cf76f8 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -203,8 +203,11 @@ again:
 	if (received < budget) {
 		netif_rx_complete(vi->dev, napi);
 		if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
-		    && netif_rx_reschedule(vi->dev, napi))
+		    && napi_schedule_prep(napi)) {
+			vi->rvq->vq_ops->disable_cb(vi->rvq);
+			__netif_rx_schedule(vi->dev, napi);
 			goto again;
+		}
 	}
 
 	return received;
@@ -278,10 +281,11 @@ again:
 		pr_debug("%s: virtio not prepared to send\n", dev->name);
 		netif_stop_queue(dev);
 
-		/* Activate callback for using skbs: if this fails it
+		/* Activate callback for using skbs: if this returns false it
 		 * means some were used in the meantime. */
 		if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
-			printk("Unlikely: restart svq failed\n");
+			printk("Unlikely: restart svq race\n");
+			vi->svq->vq_ops->disable_cb(vi->svq);
 			netif_start_queue(dev);
 			goto again;
 		}
@@ -294,6 +298,15 @@ again:
 	return 0;
 }
 
+#ifdef CONFIG_NET_POLL_CONTROLLER
+static void virtnet_netpoll(struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+
+	napi_schedule(&vi->napi);
+}
+#endif
+
 static int virtnet_open(struct net_device *dev)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
@@ -336,6 +349,9 @@ static int virtnet_probe(struct virtio_device *vdev)
 	dev->stop = virtnet_close;
 	dev->hard_start_xmit = start_xmit;
 	dev->features = NETIF_F_HIGHDMA;
+#ifdef CONFIG_NET_POLL_CONTROLLER
+	dev->poll_controller = virtnet_netpoll;
+#endif
 	SET_NETDEV_DEV(dev, &vdev->dev);
 
 	/* Do we support "hardware" checksums? */
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index c8a4332d1132..0b3efc31ee6d 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -152,7 +152,7 @@ static void virtballoon_changed(struct virtio_device *vdev)
 	wake_up(&vb->config_change);
 }
 
-static inline int towards_target(struct virtio_balloon *vb)
+static inline s64 towards_target(struct virtio_balloon *vb)
 {
 	u32 v;
 	__virtio_config_val(vb->vdev,
@@ -176,7 +176,7 @@ static int balloon(void *_vballoon)
 
 	set_freezable();
 	while (!kthread_should_stop()) {
-		int diff;
+		s64 diff;
 
 		try_to_freeze();
 		wait_event_interruptible(vb->config_change,
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 26f787ddd5ff..59a8f73dec73 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -177,6 +177,7 @@ static irqreturn_t vp_interrupt(int irq, void *opaque)
 	struct virtio_pci_device *vp_dev = opaque;
 	struct virtio_pci_vq_info *info;
 	irqreturn_t ret = IRQ_NONE;
+	unsigned long flags;
 	u8 isr;
 
 	/* reading the ISR has the effect of also clearing it so it's very
@@ -197,12 +198,12 @@ static irqreturn_t vp_interrupt(int irq, void *opaque)
 			drv->config_changed(&vp_dev->vdev);
 	}
 
-	spin_lock(&vp_dev->lock);
+	spin_lock_irqsave(&vp_dev->lock, flags);
 	list_for_each_entry(info, &vp_dev->virtqueues, node) {
 		if (vring_interrupt(irq, info->vq) == IRQ_HANDLED)
 			ret = IRQ_HANDLED;
 	}
-	spin_unlock(&vp_dev->lock);
+	spin_unlock_irqrestore(&vp_dev->lock, flags);
 
 	return ret;
 }
@@ -214,6 +215,7 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 	struct virtio_pci_vq_info *info;
 	struct virtqueue *vq;
+	unsigned long flags;
 	u16 num;
 	int err;
 
@@ -255,9 +257,9 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
 	vq->priv = info;
 	info->vq = vq;
 
-	spin_lock(&vp_dev->lock);
+	spin_lock_irqsave(&vp_dev->lock, flags);
 	list_add(&info->node, &vp_dev->virtqueues);
-	spin_unlock(&vp_dev->lock);
+	spin_unlock_irqrestore(&vp_dev->lock, flags);
 
 	return vq;
 
@@ -274,10 +276,11 @@ static void vp_del_vq(struct virtqueue *vq)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
 	struct virtio_pci_vq_info *info = vq->priv;
+	unsigned long flags;
 
-	spin_lock(&vp_dev->lock);
+	spin_lock_irqsave(&vp_dev->lock, flags);
 	list_del(&info->node);
-	spin_unlock(&vp_dev->lock);
+	spin_unlock_irqrestore(&vp_dev->lock, flags);
 
 	vring_del_virtqueue(vq);
 
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 3a28c1382131..aa714028641e 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -232,7 +232,6 @@ static bool vring_enable_cb(struct virtqueue *_vq)
 	vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
 	mb();
 	if (unlikely(more_used(vq))) {
-		vq->vring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
 		END_USE(vq);
 		return false;
 	}
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 260d1fcf29a4..12c18ac1b973 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -43,8 +43,9 @@ struct virtqueue
  *	vq: the struct virtqueue we're talking about.
  * @enable_cb: restart callbacks after disable_cb.
  *	vq: the struct virtqueue we're talking about.
- *	This returns "false" (and doesn't re-enable) if there are pending
- *	buffers in the queue, to avoid a race.
+ *	This re-enables callbacks; it returns "false" if there are pending
+ *	buffers in the queue, to detect a possible race between the driver
+ *	checking for more work, and enabling callbacks.
  *
  * Locking rules are straightforward: the driver is responsible for
  * locking.  No two operations may be invoked simultaneously.