From: Jason Wang <jasowang@redhat.com>
Date: Thu, 20 Nov 2014 08:31:05 +0000 (+0800)
Subject: macvtap: advance iov iterator when needed in macvtap_put_user()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=7cc76f51508219a74dca835745e4f84393820017;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

macvtap: advance iov iterator when needed in macvtap_put_user()

When mergeable buffer is used, vnet_hdr_sz is greater than sizeof struct
virtio_net_hdr. So we need advance the iov iterators in this case.

Fixes 6c36d2e26cda1ad3e2c4b90dd843825fc62fe5b4 ("macvtap: Use iovec iterators")
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index cea99d4a8263..42a80d3de839 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -797,6 +797,8 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q,
 		if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) !=
 		    sizeof(vnet_hdr))
 			return -EFAULT;
+
+		iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr));
 	}
 	total = vnet_hdr_len;
 	total += skb->len;