tun: fix tun_chr_aio_write so that aio works
aio_write gets const struct iovec * but tun_chr_aio_write casts this to struct
iovec * and modifies the iovec. As a result, attempts to use io_submit
to send packets to a tun device fail with weird errors such as EINVAL.
Since tun is the only user of skb_copy_datagram_from_iovec, we can
fix this simply by changing the later so that it does not
touch the iovec passed to it.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 4dbb05c..914d5fa 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -435,13 +435,15 @@
* @skb: buffer to copy
* @offset: offset in the buffer to start copying to
* @from: io vector to copy to
+ * @from_offset: offset in the io vector to start copying from
* @len: amount of data to copy to buffer from iovec
*
* Returns 0 or -EFAULT.
- * Note: the iovec is modified during the copy.
+ * Note: the iovec is not modified during the copy.
*/
int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset,
- struct iovec *from, int len)
+ const struct iovec *from, int from_offset,
+ int len)
{
int start = skb_headlen(skb);
int i, copy = start - offset;
@@ -450,11 +452,12 @@
if (copy > 0) {
if (copy > len)
copy = len;
- if (memcpy_fromiovec(skb->data + offset, from, copy))
+ if (memcpy_fromiovecend(skb->data + offset, from, 0, copy))
goto fault;
if ((len -= copy) == 0)
return 0;
offset += copy;
+ from_offset += copy;
}
/* Copy paged appendix. Hmm... why does this look so complicated? */
@@ -473,8 +476,9 @@
if (copy > len)
copy = len;
vaddr = kmap(page);
- err = memcpy_fromiovec(vaddr + frag->page_offset +
- offset - start, from, copy);
+ err = memcpy_fromiovecend(vaddr + frag->page_offset +
+ offset - start,
+ from, from_offset, copy);
kunmap(page);
if (err)
goto fault;
@@ -482,6 +486,7 @@
if (!(len -= copy))
return 0;
offset += copy;
+ from_offset += copy;
}
start = end;
}
@@ -500,11 +505,14 @@
copy = len;
if (skb_copy_datagram_from_iovec(list,
offset - start,
- from, copy))
+ from,
+ from_offset,
+ copy))
goto fault;
if ((len -= copy) == 0)
return 0;
offset += copy;
+ from_offset += copy;
}
start = end;
}