static inline int __vringh_complete()

in vringh.c [431:478]

• 39 lines of code
• 6 McCabe index (conditional complexity)

static inline int __vringh_complete(struct vringh *vrh,
				    const struct vring_used_elem *used,
				    unsigned int num_used,
				    int (*putu16)(const struct vringh *vrh,
						  __virtio16 *p, u16 val),
				    int (*putused)(const struct vringh *vrh,
						   struct vring_used_elem *dst,
						   const struct vring_used_elem
						   *src, unsigned num))
{
	struct vring_used *used_ring;
	int err;
	u16 used_idx, off;

	used_ring = vrh->vring.used;
	used_idx = vrh->last_used_idx + vrh->completed;

	off = used_idx % vrh->vring.num;

	/* Compiler knows num_used == 1 sometimes, hence extra check */
	if (num_used > 1 && unlikely(off + num_used >= vrh->vring.num)) {
		u16 part = vrh->vring.num - off;
		err = putused(vrh, &used_ring->ring[off], used, part);
		if (!err)
			err = putused(vrh, &used_ring->ring[0], used + part,
				      num_used - part);
	} else
		err = putused(vrh, &used_ring->ring[off], used, num_used);

	if (err) {
		vringh_bad("Failed to write %u used entries %u at %p",
			   num_used, off, &used_ring->ring[off]);
		return err;
	}

	/* Make sure buffer is written before we update index. */
	virtio_wmb(vrh->weak_barriers);

	err = putu16(vrh, &vrh->vring.used->idx, used_idx + num_used);
	if (err) {
		vringh_bad("Failed to update used index at %p",
			   &vrh->vring.used->idx);
		return err;
	}

	vrh->completed += num_used;
	return 0;
}