new helper: skb_copy_and_csum_datagram_msg()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
new helper: memcpy_from_msg()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
switch ipxrtr_route_packet() from iovec to msghdr

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
new helper: memcpy_to_msg()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
switch drivers/net/tun.c to ->read_iter()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
switch macvtap to ->read_iter()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
new helpers: skb_copy_datagram_from_iter() and zerocopy_sg_from_iter()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
{macvtap,tun}_get_user(): switch to iov_iter

allows to switch macvtap and tun from ->aio_write() to ->write_iter()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
kill zerocopy_sg_from_iovec()

no users left

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
switch AF_PACKET and AF_UNIX to skb_copy_datagram_from_iter()

... and kill skb_copy_datagram_iovec()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
switch sctp_user_addto_chunk() and sctp_datamsg_from_user() to passing iov_iter

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
tipc_sendmsg(): pass msghdr instead of its ->msg_iov

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
tipc_msg_build(): pass msghdr instead of its ->msg_iov

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
vmci_transport: switch ->enqeue_dgram, ->enqueue_stream and ->dequeue_stream to msghdr

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[atm] switch vcc_sendmsg() to copy_from_iter()

... and make it handle multi-segment iovecs - deals with that
"fix this later" issue for free.  A bit of shame, really - it
had been there since 2.3.15pre3 when the whole thing went into the
tree, practically a historical artefact by now...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
rds: switch ->inc_copy_to_user() to passing iov_iter

instances get considerably simpler from that...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
rds: switch rds_message_copy_from_user() to iov_iter

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Merge branch 'for-davem' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

More work from Al Viro to move away from modifying iovecs
by using iov_iter instead.

Signed-off-by: David S. Miller <davem@davemloft.net>