static void detach_buf_split()

in virtio_ring.c [692:740]

• 34 lines of code
• 7 McCabe index (conditional complexity)

static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head,
			     void **ctx)
{
	unsigned int i, j;
	__virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);

	/* Clear data ptr. */
	vq->split.desc_state[head].data = NULL;

	/* Put back on free list: unmap first-level descriptors and find end */
	i = head;

	while (vq->split.vring.desc[i].flags & nextflag) {
		vring_unmap_one_split(vq, i);
		i = vq->split.desc_extra[i].next;
		vq->vq.num_free++;
	}

	vring_unmap_one_split(vq, i);
	vq->split.desc_extra[i].next = vq->free_head;
	vq->free_head = head;

	/* Plus final descriptor */
	vq->vq.num_free++;

	if (vq->indirect) {
		struct vring_desc *indir_desc =
				vq->split.desc_state[head].indir_desc;
		u32 len;

		/* Free the indirect table, if any, now that it's unmapped. */
		if (!indir_desc)
			return;

		len = vq->split.desc_extra[head].len;

		BUG_ON(!(vq->split.desc_extra[head].flags &
				VRING_DESC_F_INDIRECT));
		BUG_ON(len == 0 || len % sizeof(struct vring_desc));

		for (j = 0; j < len / sizeof(struct vring_desc); j++)
			vring_unmap_one_split_indirect(vq, &indir_desc[j]);

		kfree(indir_desc);
		vq->split.desc_state[head].indir_desc = NULL;
	} else if (ctx) {
		*ctx = vq->split.desc_state[head].indir_desc;
	}
}