macvtap: zerocopy: fix offset calculation when building skb
commit 3afc9621f15701c557e60f61eba9242bac2771dd upstream.
This patch fixes the offset calculation when building skb:
- offset1 were used as skb data offset not vector offset
- reset offset to zero only when we advance to next vector
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 c1d602d..0302bc5 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -506,10 +506,11 @@
if (copy > size) {
++from;
--count;
- }
+ offset = 0;
+ } else
+ offset += size;
copy -= size;
offset1 += size;
- offset = 0;
}
if (len == offset1)
@@ -520,13 +521,13 @@
int num_pages;
unsigned long base;
- len = from->iov_len - offset1;
+ len = from->iov_len - offset;
if (!len) {
- offset1 = 0;
+ offset = 0;
++from;
continue;
}
- base = (unsigned long)from->iov_base + offset1;
+ base = (unsigned long)from->iov_base + offset;
size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
if (i + size > MAX_SKB_FRAGS)
return -EMSGSIZE;
@@ -548,7 +549,7 @@
len -= size;
i++;
}
- offset1 = 0;
+ offset = 0;
++from;
}
return 0;