target: Allow control CDBs with data > 1 page

We need to handle >1 page control cdbs, so extend the code to do a vmap
if bigger than 1 page. It seems like kmap() is still preferable if just
a page, fewer TLB shootdowns(?), so keep using that when possible.

Rename function pair for their new scope.

Signed-off-by: Andy Grover <agrover@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index 4866499..e5e6ff9 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -59,7 +59,7 @@
 int	transport_set_vpd_ident(struct t10_vpd *, unsigned char *);
 
 /* core helpers also used by command snooping in pscsi */
-void	*transport_kmap_first_data_page(struct se_cmd *);
-void	transport_kunmap_first_data_page(struct se_cmd *);
+void	*transport_kmap_data_sg(struct se_cmd *);
+void	transport_kunmap_data_sg(struct se_cmd *);
 
 #endif /* TARGET_CORE_BACKEND_H */