Commit 1ab5d138 authored by Jason Wang's avatar Jason Wang Committed by Michael S. Tsirkin
Browse files

vhost: generalize adding used elem 



Use one generic vhost_copy_to_user() instead of two dedicated
accessor. This will simplify the conversion to fine grain
accessors. About 2% improvement of PPS were seen during vitio-user
txonly test.

Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent c1ea02f1

drivers/vhost/vhost.c

+1 −10
Original line number Diff line number Diff line
@@ -2273,16 +2273,7 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq, 


	start = vq->last_used_idx & (vq->num - 1);

	used = vq->used->ring + start;

	if (count == 1) {

		if (vhost_put_user(vq, heads[0].id, &used->id)) {

			vq_err(vq, "Failed to write used id");

			return -EFAULT;

		}

		if (vhost_put_user(vq, heads[0].len, &used->len)) {

			vq_err(vq, "Failed to write used len");

			return -EFAULT;

		}

	} else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) {

	if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) {

		vq_err(vq, "Failed to write used");

		return -EFAULT;

	}

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