virtio-net: realign page_to_skb() after merges

We ended up merging two versions of the same patch set:

commit 8fb7da9e9907 ("virtio_net: get build_skb() buf by data ptr")
commit 5c37711d9f27 ("virtio-net: fix for unable to handle page fault for address")

into net, and

commit 7bf64460e3b2 ("virtio-net: get build_skb() buf by data ptr")
commit 6c66c147b9a4 ("virtio-net: fix for unable to handle page fault for address")

into net-next. Redo the merge from commit 126285651b7f ("Merge
ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net"), so that
the most recent code remains.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 56c3f85..74482a5 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -380,7 +380,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
                                   struct page *page, unsigned int offset,
                                   unsigned int len, unsigned int truesize,
                                   bool hdr_valid, unsigned int metasize,
-                                  bool whole_page)
+                                  unsigned int headroom)
 {
        struct sk_buff *skb;
        struct virtio_net_hdr_mrg_rxbuf *hdr;
@@ -398,28 +398,16 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
        else
                hdr_padded_len = sizeof(struct padded_vnet_hdr);
 
-       /* If whole_page, there is an offset between the beginning of the
+       /* If headroom is not 0, there is an offset between the beginning of the
         * data and the allocated space, otherwise the data and the allocated
         * space are aligned.
         *
         * Buffers with headroom use PAGE_SIZE as alloc size, see
         * add_recvbuf_mergeable() + get_mergeable_buf_len()
         */
-       if (whole_page) {
-               /* Buffers with whole_page use PAGE_SIZE as alloc size,
-                * see add_recvbuf_mergeable() + get_mergeable_buf_len()
-                */
-               truesize = PAGE_SIZE;
-
-               /* page maybe head page, so we should get the buf by p, not the
-                * page
-                */
-               tailroom = truesize - len - offset_in_page(p);
-               buf = (char *)((unsigned long)p & PAGE_MASK);
-       } else {
-               tailroom = truesize - len;
-               buf = p;
-       }
+       truesize = headroom ? PAGE_SIZE : truesize;
+       tailroom = truesize - len - headroom;
+       buf = p - headroom;
 
        len -= hdr_len;
        offset += hdr_padded_len;
@@ -978,7 +966,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
                                put_page(page);
                                head_skb = page_to_skb(vi, rq, xdp_page, offset,
                                                       len, PAGE_SIZE, false,
-                                                      metasize, true);
+                                                      metasize,
+                                                      VIRTIO_XDP_HEADROOM);
                                return head_skb;
                        }
                        break;
@@ -1029,7 +1018,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
        rcu_read_unlock();
 
        head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog,
-                              metasize, !!headroom);
+                              metasize, headroom);
        curr_skb = head_skb;
 
        if (unlikely(!curr_skb))