From: Jason Wang <jasowang@redhat.com>
Date: Wed, 2 May 2012 03:41:44 +0000 (+0800)
Subject: macvtap: zerocopy: fix truesize underestimation
X-Git-Tag: v3.4.12~52
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=bfd1678ca0143060686d87ae0c07bebab6f0245b;p=karo-tx-linux.git

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>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 0302bc5adc69..cf096e0693e2 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -520,6 +520,7 @@ 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) {
@@ -535,10 +536,11 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
 		if (num_pages != size)
 			/* 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);