[PATCH vhost 5/6] virtio_net: enable premapped by default

[Xuan Zhuo <xuanzhuo@linux.alibaba.com>]

Currently, big, merge, and small modes all support the premapped mode.
We can now enable premapped mode by default. Furthermore,
virtqueue_set_dma_premapped() must succeed when called immediately after
find_vqs(). Consequently, we can assume that premapped mode is always
enabled.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 7ea7e9bcd5d7..f0faf7c0fe59 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -860,15 +860,13 @@ static void *virtnet_rq_alloc(struct receive_queue *rq, u32 size, gfp_t gfp)
 
 static void virtnet_rq_set_premapped(struct virtnet_info *vi)
 {
-	int i;
-
-	/* disable for big mode */
-	if (!vi->mergeable_rx_bufs && vi->big_packets)
-		return;
+	int i, err;
 
 	for (i = 0; i < vi->max_queue_pairs; i++) {
-		if (virtqueue_set_dma_premapped(vi->rq[i].vq))
-			continue;
+		err = virtqueue_set_dma_premapped(vi->rq[i].vq);
+
+		/* never happen */
+		BUG_ON(err);
 
 		vi->rq[i].do_dma = true;
 	}
-- 
2.32.0.3.g01195cf9f