cifs: Don't advance the I/O iterator before terminating subrequest

There's now no need to make sure subreq->io_iter is advanced to match
subreq->transferred before calling one of the netfs subrequest termination
functions as the check has been removed netfslib and the iterator is reset
prior to retrying a subreq.

Fixes: 3ee1a1f ("cifs: Cut over to using netfslib")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: dhowells

fs/smb/client/smb2pdu.c

@@ -4577,8 +4577,6 @@ smb2_readv_callback(struct mid_q_entry *mid)
 		if (rdata->subreq.start < rdata->subreq.rreq->i_size)
 			rdata->result = 0;
 	}
-	if (rdata->result == 0 || rdata->result == -EAGAIN)
-		iov_iter_advance(&rdata->subreq.io_iter, rdata->got_bytes);
 	rdata->credits.value = 0;
 	netfs_subreq_terminated(&rdata->subreq,
 				(rdata->result == 0 || rdata->result == -EAGAIN) ?
@@ -4789,7 +4787,6 @@ smb2_writev_callback(struct mid_q_entry *mid)
 			wdata->result = -ENOSPC;
 		else
 			wdata->subreq.len = written;
-		iov_iter_advance(&wdata->subreq.io_iter, written);
 		break;
 	case MID_REQUEST_SUBMITTED:
 	case MID_RETRY_NEEDED: