From d2e1446d81725c351dc73a03b397ce043fb18452 Mon Sep 17 00:00:00 2001
From: Meizu OpenSource <patchwork@meizu.com>
Date: Mon, 15 Aug 2016 10:19:42 +0800
Subject: first commit

---
 include/linux/virtio_ring.h | 81 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 include/linux/virtio_ring.h

(limited to 'include/linux/virtio_ring.h')

diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
new file mode 100644
index 000000000..ca3ad41c2
--- /dev/null
+++ b/include/linux/virtio_ring.h
@@ -0,0 +1,81 @@
+#ifndef _LINUX_VIRTIO_RING_H
+#define _LINUX_VIRTIO_RING_H
+
+#include <linux/irqreturn.h>
+#include <uapi/linux/virtio_ring.h>
+
+/*
+ * Barriers in virtio are tricky.  Non-SMP virtio guests can't assume
+ * they're not on an SMP host system, so they need to assume real
+ * barriers.  Non-SMP virtio hosts could skip the barriers, but does
+ * anyone care?
+ *
+ * For virtio_pci on SMP, we don't need to order with respect to MMIO
+ * accesses through relaxed memory I/O windows, so smp_mb() et al are
+ * sufficient.
+ *
+ * For using virtio to talk to real devices (eg. other heterogeneous
+ * CPUs) we do need real barriers.  In theory, we could be using both
+ * kinds of virtio, so it's a runtime decision, and the branch is
+ * actually quite cheap.
+ */
+
+#ifdef CONFIG_SMP
+static inline void virtio_mb(bool weak_barriers)
+{
+	if (weak_barriers)
+		smp_mb();
+	else
+		mb();
+}
+
+static inline void virtio_rmb(bool weak_barriers)
+{
+	if (weak_barriers)
+		smp_rmb();
+	else
+		rmb();
+}
+
+static inline void virtio_wmb(bool weak_barriers)
+{
+	if (weak_barriers)
+		smp_wmb();
+	else
+		wmb();
+}
+#else
+static inline void virtio_mb(bool weak_barriers)
+{
+	mb();
+}
+
+static inline void virtio_rmb(bool weak_barriers)
+{
+	rmb();
+}
+
+static inline void virtio_wmb(bool weak_barriers)
+{
+	wmb();
+}
+#endif
+
+struct virtio_device;
+struct virtqueue;
+
+struct virtqueue *vring_new_virtqueue(unsigned int index,
+				      unsigned int num,
+				      unsigned int vring_align,
+				      struct virtio_device *vdev,
+				      bool weak_barriers,
+				      void *pages,
+				      void (*notify)(struct virtqueue *vq),
+				      void (*callback)(struct virtqueue *vq),
+				      const char *name);
+void vring_del_virtqueue(struct virtqueue *vq);
+/* Filter out transport-specific feature bits. */
+void vring_transport_features(struct virtio_device *vdev);
+
+irqreturn_t vring_interrupt(int irq, void *_vq);
+#endif /* _LINUX_VIRTIO_RING_H */
-- 
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