[ 018/108] macvtap: zerocopy: put page when fail to get all requested user pages

Ben Hutchings
2012-07-23T01:42:16Z

From: Jason Wang <jasowang@redhat.com>

commit 02ce04bb3d28c3333231f43bca677228dbc686fe upstream.

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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/net/macvtap.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

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