Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

4 files changed, 73 insertions, 39 deletions

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index b535483bc556..7084e7e146c0 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -2,6 +2,9 @@
 #include <linux/spinlock.h>
 #include <linux/virtio_config.h>
 
+/* Unique numbering for virtio devices. */
+static unsigned int dev_index;
+
 static ssize_t device_show(struct device *_d,
 			   struct device_attribute *attr, char *buf)
 {
@@ -80,19 +83,51 @@ static void add_status(struct virtio_device *dev, unsigned status)
 	dev->config->set_status(dev, dev->config->get_status(dev) | status);
 }
 
+void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
+					 unsigned int fbit)
+{
+	unsigned int i;
+	struct virtio_driver *drv = container_of(vdev->dev.driver,
+						 struct virtio_driver, driver);
+
+	for (i = 0; i < drv->feature_table_size; i++)
+		if (drv->feature_table[i] == fbit)
+			return;
+	BUG();
+}
+EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
+
 static int virtio_dev_probe(struct device *_d)
 {
-	int err;
+	int err, i;
 	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
 	struct virtio_driver *drv = container_of(dev->dev.driver,
 						 struct virtio_driver, driver);
+	u32 device_features;
 
+	/* We have a driver! */
 	add_status(dev, VIRTIO_CONFIG_S_DRIVER);
+
+	/* Figure out what features the device supports. */
+	device_features = dev->config->get_features(dev);
+
+	/* Features supported by both device and driver into dev->features. */
+	memset(dev->features, 0, sizeof(dev->features));
+	for (i = 0; i < drv->feature_table_size; i++) {
+		unsigned int f = drv->feature_table[i];
+		BUG_ON(f >= 32);
+		if (device_features & (1 << f))
+			set_bit(f, dev->features);
+	}
+
 	err = drv->probe(dev);
 	if (err)
 		add_status(dev, VIRTIO_CONFIG_S_FAILED);
-	else
+	else {
+		/* They should never have set feature bits beyond 32 */
+		dev->config->set_features(dev, dev->features[0]);
 		add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
+	}
 	return err;
 }
 
@@ -114,6 +149,8 @@ static int virtio_dev_remove(struct device *_d)
 
 int register_virtio_driver(struct virtio_driver *driver)
 {
+	/* Catch this early. */
+	BUG_ON(driver->feature_table_size && !driver->feature_table);
 	driver->driver.bus = &virtio_bus;
 	driver->driver.probe = virtio_dev_probe;
 	driver->driver.remove = virtio_dev_remove;
@@ -132,7 +169,10 @@ int register_virtio_device(struct virtio_device *dev)
 	int err;
 
 	dev->dev.bus = &virtio_bus;
-	sprintf(dev->dev.bus_id, "%u", dev->index);
+
+	/* Assign a unique device index and hence name. */
+	dev->index = dev_index++;
+	sprintf(dev->dev.bus_id, "virtio%u", dev->index);
 
 	/* We always start by resetting the device, in case a previous
 	 * driver messed it up.  This also tests that code path a little. */
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 0b3efc31ee6d..bfef604160d1 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -155,9 +155,9 @@ static void virtballoon_changed(struct virtio_device *vdev)
 static inline s64 towards_target(struct virtio_balloon *vb)
 {
 	u32 v;
-	__virtio_config_val(vb->vdev,
-			    offsetof(struct virtio_balloon_config, num_pages),
-			    &v);
+	vb->vdev->config->get(vb->vdev,
+			      offsetof(struct virtio_balloon_config, num_pages),
+			      &v, sizeof(v));
 	return v - vb->num_pages;
 }
 
@@ -227,7 +227,7 @@ static int virtballoon_probe(struct virtio_device *vdev)
 	}
 
 	vb->tell_host_first
-		= vdev->config->feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST);
+		= virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST);
 
 	return 0;
 
@@ -259,7 +259,11 @@ static void virtballoon_remove(struct virtio_device *vdev)
 	kfree(vb);
 }
 
+static unsigned int features[] = { VIRTIO_BALLOON_F_MUST_TELL_HOST };
+
 static struct virtio_driver virtio_balloon = {
+	.feature_table = features,
+	.feature_table_size = ARRAY_SIZE(features),
 	.driver.name =	KBUILD_MODNAME,
 	.driver.owner =	THIS_MODULE,
 	.id_table =	id_table,
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index c0df924766a7..eae7236310e4 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -78,32 +78,28 @@ static struct device virtio_pci_root = {
 	.bus_id		= "virtio-pci",
 };
 
-/* Unique numbering for devices under the kvm root */
-static unsigned int dev_index;
-
 /* Convert a generic virtio device to our structure */
 static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
 {
 	return container_of(vdev, struct virtio_pci_device, vdev);
 }
 
-/* virtio config->feature() implementation */
-static bool vp_feature(struct virtio_device *vdev, unsigned bit)
+/* virtio config->get_features() implementation */
+static u32 vp_get_features(struct virtio_device *vdev)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
-	u32 mask;
-
-	/* Since this function is supposed to have the side effect of
-	 * enabling a queried feature, we simulate that by doing a read
-	 * from the host feature bitmask and then writing to the guest
-	 * feature bitmask */
-	mask = ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
-	if (mask & (1 << bit)) {
-		mask |= (1 << bit);
-		iowrite32(mask, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
-	}
 
-	return !!(mask & (1 << bit));
+	/* When someone needs more than 32 feature bits, we'll need to
+	 * steal a bit to indicate that the rest are somewhere else. */
+	return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
+}
+
+/* virtio config->set_features() implementation */
+static void vp_set_features(struct virtio_device *vdev, u32 features)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+
+	iowrite32(features, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
 }
 
 /* virtio config->get() implementation */
@@ -145,14 +141,14 @@ static void vp_set_status(struct virtio_device *vdev, u8 status)
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 	/* We should never be setting status to 0. */
 	BUG_ON(status == 0);
-	return iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
+	iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 }
 
 static void vp_reset(struct virtio_device *vdev)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 	/* 0 status means a reset. */
-	return iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
+	iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 }
 
 /* the notify function used when creating a virt queue */
@@ -293,7 +289,6 @@ static void vp_del_vq(struct virtqueue *vq)
 }
 
 static struct virtio_config_ops virtio_pci_config_ops = {
-	.feature	= vp_feature,
 	.get		= vp_get,
 	.set		= vp_set,
 	.get_status	= vp_get_status,
@@ -301,6 +296,8 @@ static struct virtio_config_ops virtio_pci_config_ops = {
 	.reset		= vp_reset,
 	.find_vq	= vp_find_vq,
 	.del_vq		= vp_del_vq,
+	.get_features	= vp_get_features,
+	.set_features	= vp_set_features,
 };
 
 /* the PCI probing function */
@@ -325,10 +322,6 @@ static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
 	if (vp_dev == NULL)
 		return -ENOMEM;
 
-	snprintf(vp_dev->vdev.dev.bus_id, BUS_ID_SIZE, "virtio%d", dev_index);
-	vp_dev->vdev.index = dev_index;
-	dev_index++;
-
 	vp_dev->vdev.dev.parent = &virtio_pci_root;
 	vp_dev->vdev.config = &virtio_pci_config_ops;
 	vp_dev->pci_dev = pci_dev;
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index c2fa5c630813..72bf8bc09014 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -184,6 +184,11 @@ static void *vring_get_buf(struct virtqueue *_vq, unsigned int *len)
 
 	START_USE(vq);
 
+	if (unlikely(vq->broken)) {
+		END_USE(vq);
+		return NULL;
+	}
+
 	if (!more_used(vq)) {
 		pr_debug("No more buffers in queue\n");
 		END_USE(vq);
@@ -222,7 +227,6 @@ static bool vring_enable_cb(struct virtqueue *_vq)
 	struct vring_virtqueue *vq = to_vvq(_vq);
 
 	START_USE(vq);
-	BUG_ON(!(vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT));
 
 	/* We optimistically turn back on interrupts, then check if there was
 	 * more to do. */
@@ -249,13 +253,6 @@ irqreturn_t vring_interrupt(int irq, void *_vq)
 	if (unlikely(vq->broken))
 		return IRQ_HANDLED;
 
-	/* Other side may have missed us turning off the interrupt,
-	 * but we should preserve disable semantic for virtio users. */
-	if (unlikely(vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) {
-		pr_debug("virtqueue interrupt after disable for %p\n", vq);
-		return IRQ_HANDLED;
-	}
-
 	pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback);
 	if (vq->vq.callback)
 		vq->vq.callback(&vq->vq);