macvtap: zerocopy: put page when fail to get all requested user pages

When get_user_pages_fast() fails to get all requested pages, we could not use
kfree_skb() to free it as it has not been put in the skb fragments. So we need
to call put_page() instead.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 7cb2684a8792..9ab182a40648 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -531,9 +531,11 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
                 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
                 num_pages = get_user_pages_fast(base, size, 0, &page[i]);
                 if ((num_pages != size) ||
-                    (num_pages > MAX_SKB_FRAGS - skb_shinfo(skb)->nr_frags))
-                        /* put_page is in skb free */
+                    (num_pages > MAX_SKB_FRAGS - skb_shinfo(skb)->nr_frags)) {
+                        for (i = 0; i < num_pages; i++)
+                                put_page(page[i]);
                         return -EFAULT;
+                }
                 truesize = size * PAGE_SIZE;
                 skb->data_len += len;
                 skb->len += len;