[RFC PATCH v2 3/7] Revert "virtio_net: xsk: rx: support fill with xsk buffer"

["Michael S. Tsirkin" <mst@xxxxxxxxxx>]

This reverts commit e9f3962441c0a4d6f16c656e6c8aa02a3ccdd568.

leads to crashes with no ACCESS_PLATFORM when
sysctl net.core.high_order_alloc_disable=1

Cc: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
Reported-by: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
 drivers/net/virtio_net.c | 70 +++-------------------------------------
 1 file changed, 4 insertions(+), 66 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 041c483a06c5..3cb0f8adf2e6 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -354,8 +354,6 @@ struct receive_queue {
 
 	/* xdp rxq used by xsk */
 	struct xdp_rxq_info xsk_rxq_info;
-
-	struct xdp_buff **xsk_buffs;
 };
 
 /* This structure can contain rss message with maximum settings for indirection table and keysize
@@ -1056,53 +1054,6 @@ static void check_sq_full_and_disable(struct virtnet_info *vi,
 	}
 }
 
-static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
-{
-	sg->dma_address = addr;
-	sg->length = len;
-}
-
-static int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct receive_queue *rq,
-				   struct xsk_buff_pool *pool, gfp_t gfp)
-{
-	struct xdp_buff **xsk_buffs;
-	dma_addr_t addr;
-	int err = 0;
-	u32 len, i;
-	int num;
-
-	xsk_buffs = rq->xsk_buffs;
-
-	num = xsk_buff_alloc_batch(pool, xsk_buffs, rq->vq->num_free);
-	if (!num)
-		return -ENOMEM;
-
-	len = xsk_pool_get_rx_frame_size(pool) + vi->hdr_len;
-
-	for (i = 0; i < num; ++i) {
-		/* Use the part of XDP_PACKET_HEADROOM as the virtnet hdr space.
-		 * We assume XDP_PACKET_HEADROOM is larger than hdr->len.
-		 * (see function virtnet_xsk_pool_enable)
-		 */
-		addr = xsk_buff_xdp_get_dma(xsk_buffs[i]) - vi->hdr_len;
-
-		sg_init_table(rq->sg, 1);
-		sg_fill_dma(rq->sg, addr, len);
-
-		err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, xsk_buffs[i], gfp);
-		if (err)
-			goto err;
-	}
-
-	return num;
-
-err:
-	for (; i < num; ++i)
-		xsk_buff_free(xsk_buffs[i]);
-
-	return err;
-}
-
 static int virtnet_xsk_wakeup(struct net_device *dev, u32 qid, u32 flag)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
@@ -2294,11 +2245,7 @@ static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
 			  gfp_t gfp)
 {
 	int err;
-
-	if (rq->xsk_pool) {
-		err = virtnet_add_recvbuf_xsk(vi, rq, rq->xsk_pool, gfp);
-		goto kick;
-	}
+	bool oom;
 
 	do {
 		if (vi->mergeable_rx_bufs)
@@ -2308,11 +2255,10 @@ static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
 		else
 			err = add_recvbuf_small(vi, rq, gfp);
 
+		oom = err == -ENOMEM;
 		if (err)
 			break;
 	} while (rq->vq->num_free);
-
-kick:
 	if (virtqueue_kick_prepare(rq->vq) && virtqueue_notify(rq->vq)) {
 		unsigned long flags;
 
@@ -2321,7 +2267,7 @@ static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
 		u64_stats_update_end_irqrestore(&rq->stats.syncp, flags);
 	}
 
-	return err != -ENOMEM;
+	return !oom;
 }
 
 static void skb_recv_done(struct virtqueue *rvq)
@@ -5168,7 +5114,7 @@ static int virtnet_xsk_pool_enable(struct net_device *dev,
 	struct receive_queue *rq;
 	struct device *dma_dev;
 	struct send_queue *sq;
-	int err, size;
+	int err;
 
 	if (vi->hdr_len > xsk_pool_get_headroom(pool))
 		return -EINVAL;
@@ -5199,12 +5145,6 @@ static int virtnet_xsk_pool_enable(struct net_device *dev,
 	if (!dma_dev)
 		return -EINVAL;
 
-	size = virtqueue_get_vring_size(rq->vq);
-
-	rq->xsk_buffs = kvcalloc(size, sizeof(*rq->xsk_buffs), GFP_KERNEL);
-	if (!rq->xsk_buffs)
-		return -ENOMEM;
-
 	err = xsk_pool_dma_map(pool, dma_dev, 0);
 	if (err)
 		goto err_xsk_map;
@@ -5239,8 +5179,6 @@ static int virtnet_xsk_pool_disable(struct net_device *dev, u16 qid)
 
 	xsk_pool_dma_unmap(pool, 0);
 
-	kvfree(rq->xsk_buffs);
-
 	return err;
 }
 
-- 
MST