macvtap: zerocopy: fix truesize underestimation

commit 4ef67ebedffa44ed9939b34708ac2fee06d2f65f upstream.

As the skb fragment were pinned/built from user pages, we should
account the page instead of length for truesize.

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>

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 45050085c8ce0439d58e46dafa77a7348c92a75e..c7a84eb75d1ae5b909f2b49054127c16babf9799 100644 (file)
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -518,6 +518,7 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
                struct page *page[MAX_SKB_FRAGS];
                int num_pages;
                unsigned long base;
+               unsigned long truesize;
 
                len = from->iov_len - offset;
                if (!len) {
@@ -532,10 +533,11 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
                    (num_pages > MAX_SKB_FRAGS - skb_shinfo(skb)->nr_frags))
                        /* put_page is in skb free */
                        return -EFAULT;
+               truesize = size * PAGE_SIZE;
                skb->data_len += len;
                skb->len += len;
-               skb->truesize += len;
-               atomic_add(len, &skb->sk->sk_wmem_alloc);
+               skb->truesize += truesize;
+               atomic_add(truesize, &skb->sk->sk_wmem_alloc);
                while (len) {
                        int off = base & ~PAGE_MASK;
                        int size = min_t(int, len, PAGE_SIZE - off);