GIF89a;
avail->ring[(vr)->num]) #define vring_avail_event(vr) (*(__virtio16 *)&(vr)->used->ring[(vr)->num]) static __inline__ void vring_init(struct vring *vr, unsigned int num, void *p, unsigned long align) { vr->num = num; vr->desc = p; vr->avail = p + num*sizeof(struct vring_desc); vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + sizeof(__virtio16) + align-1) & ~(align - 1)); } static __inline__ unsigned vring_size(unsigned int num, unsigned long align) { return ((sizeof(struct vring_desc) * num + sizeof(__virtio16) * (3 + num) + align - 1) & ~(align - 1)) + sizeof(__virtio16) * 3 + sizeof(struct vring_used_elem) * num; } /* The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX */ /* Assuming a given event_idx value from the other size, if * we have just incremented index from old to new_idx, * should we trigger an event? */ static __inline__ int vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old) { /* Note: Xen has similar logic for notification hold-off * in include/xen/interface/io/ring.h with req_event and req_prod * corresponding to event_idx + 1 and new_idx respectively. * Note also that req_event and req_prod in Xen start at 1, * event indexes in virtio start at 0. */ return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old); } #endif /* _LINUX_VIRTIO_RING_H */