Fix datagram recvmsg NULL iov handling regression.
commit
ef8aef55ce61fd0e2af798695f7386ac756ae1e7 in mainline
Subject: [PATCH] [NET]: Do not dereference iov if length is zero
When msg_iovlen is zero we shouldn't try to dereference
msg_iov. Right now the only thing that tries to do so
is skb_copy_and_csum_datagram_iovec. Since the total
length should also be zero if msg_iovlen is zero, it's
sufficient to check the total length there and simply
return if it's zero.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>