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>

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 7cb2684..9ab182a 100644 (file)
--- 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;