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

[Michael S. Tsirkin]

This reverts commit e9f3962441c0a4d6f16c656e6c8aa02a3ccdd568.

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

Cc: Xuan Zhuo <xuanz...@linux.alibaba.com>
Reported-by: Si-Wei Liu <si-wei....@oracle.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
---
 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