[deliverable/linux.git] / include / linux / virtio_ring.h

#ifndef _LINUX_VIRTIO_RING_H
#define _LINUX_VIRTIO_RING_H

#include <asm/barrier.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.
 */

static inline void virtio_mb(bool weak_barriers)
{
#ifdef CONFIG_SMP
	if (weak_barriers)
		smp_mb();
	else
#endif
		mb();
}

static inline void virtio_rmb(bool weak_barriers)
{
	if (weak_barriers)
		dma_rmb();
	else
		rmb();
}

static inline void virtio_wmb(bool weak_barriers)
{
	if (weak_barriers)
		dma_wmb();
	else
		wmb();
}

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,
				      bool (*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 */
Commit	Line	Data
	1	#ifndef _LINUX_VIRTIO_RING_H
	2	#define _LINUX_VIRTIO_RING_H
	3
	4	#include <asm/barrier.h>
	5	#include <linux/irqreturn.h>
	6	#include <uapi/linux/virtio_ring.h>
	7
	8	/*
	9	* Barriers in virtio are tricky. Non-SMP virtio guests can't assume
	10	* they're not on an SMP host system, so they need to assume real
	11	* barriers. Non-SMP virtio hosts could skip the barriers, but does
	12	* anyone care?
	13	*
	14	* For virtio_pci on SMP, we don't need to order with respect to MMIO
	15	* accesses through relaxed memory I/O windows, so smp_mb() et al are
	16	* sufficient.
	17	*
	18	* For using virtio to talk to real devices (eg. other heterogeneous
	19	* CPUs) we do need real barriers. In theory, we could be using both
	20	* kinds of virtio, so it's a runtime decision, and the branch is
	21	* actually quite cheap.
	22	*/
	23
	24	static inline void virtio_mb(bool weak_barriers)
	25	{
	26	#ifdef CONFIG_SMP
	27	if (weak_barriers)
	28	smp_mb();
	29	else
	30	#endif
	31	mb();
	32	}
	33
	34	static inline void virtio_rmb(bool weak_barriers)
	35	{
	36	if (weak_barriers)
	37	dma_rmb();
	38	else
	39	rmb();
	40	}
	41
	42	static inline void virtio_wmb(bool weak_barriers)
	43	{
	44	if (weak_barriers)
	45	dma_wmb();
	46	else
	47	wmb();
	48	}
	49
	50	struct virtio_device;
	51	struct virtqueue;
	52
	53	struct virtqueue *vring_new_virtqueue(unsigned int index,
	54	unsigned int num,
	55	unsigned int vring_align,
	56	struct virtio_device *vdev,
	57	bool weak_barriers,
	58	void *pages,
	59	bool (notify)(struct virtqueue vq),
	60	void (callback)(struct virtqueue vq),
	61	const char *name);
	62	void vring_del_virtqueue(struct virtqueue *vq);
	63	/* Filter out transport-specific feature bits. */
	64	void vring_transport_features(struct virtio_device *vdev);
	65
	66	irqreturn_t vring_interrupt(int irq, void *_vq);
	67	#endif /* _LINUX_VIRTIO_RING_H */