Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-lguest-and-virtio

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-lguest-and-virtio:
  lguest: barrier me harder
  lguest: use bool instead of int
  lguest: use KVM hypercalls
  lguest: wire up pte_update/pte_update_defer
  lguest: fix spurious BUG_ON() on invalid guest stack.
  virtio: more neatening of virtio_ring macros.
  virtio: fix BAD_RING, START_US and END_USE macros

1 files changed, 14 insertions, 8 deletions

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 5777196bf6c9..5c52369ab9bb 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -23,15 +23,21 @@
 
 #ifdef DEBUG
 /* For development, we want to crash whenever the ring is screwed. */
-#define BAD_RING(vq, fmt...)                    \
-        do { dev_err(&vq->vq.vdev->dev, fmt); BUG(); } while(0)
-#define START_USE(vq) \
-        do { if ((vq)->in_use) panic("in_use = %i\n", (vq)->in_use); (vq)->in_use = __LINE__; mb(); } while(0)
-#define END_USE(vq) \
-        do { BUG_ON(!(vq)->in_use); (vq)->in_use = 0; mb(); } while(0)
+#define BAD_RING(_vq, fmt...)                   \
+        do { dev_err(&(_vq)->vq.vdev->dev, fmt); BUG(); } while(0)
+/* Caller is supposed to guarantee no reentry. */
+#define START_USE(_vq)                                          \
+        do {                                                    \
+                if ((_vq)->in_use)                              \
+                        panic("in_use = %i\n", (_vq)->in_use);  \
+                (_vq)->in_use = __LINE__;                       \
+                mb();                                           \
+        } while(0)
+#define END_USE(_vq) \
+        do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; mb(); } while(0)
 #else
-#define BAD_RING(vq, fmt...)                    \
-        do { dev_err(&vq->vq.vdev->dev, fmt); (vq)->broken = true; } while(0)
+#define BAD_RING(_vq, fmt...)                   \
+        do { dev_err(&_vq->vq.vdev->dev, fmt); (_vq)->broken = true; } while(0)
 #define START_USE(vq)
 #define END_USE(vq)
 #endif