2 files changed, 7 insertions, 1 deletions

diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index b7f990962ff6..cbf9b0080bf8 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -2917,7 +2917,10 @@ vm_map_lookup_done(vm_map_t map, vm_map_entry_t entry)
 	vm_map_unlock_read(map);
 }
 
+#ifdef ENABLE_VFS_IOOPT
 /*
+ * Experimental support for zero-copy I/O
+ *
  * Implement uiomove with VM operations.  This handles (and collateral changes)
  * support every combination of source object modification, and COW type
  * operations.
@@ -3149,6 +3152,7 @@ vm_uiomove(
 	}
 	return 0;
 }
+#endif
 
 /*
  * Performs the copy_on_write operations necessary to allow the virtual copies
diff --git a/sys/vm/vm_map.h b/sys/vm/vm_map.h
index 8156682ce999..0b8777768255 100644
--- a/sys/vm/vm_map.h
+++ b/sys/vm/vm_map.h
@@ -300,11 +300,13 @@ int vm_map_submap (vm_map_t, vm_offset_t, vm_offset_t, vm_map_t);
 int vm_map_madvise (vm_map_t, vm_offset_t, vm_offset_t, int);
 void vm_map_simplify_entry (vm_map_t, vm_map_entry_t);
 void vm_init2 (void);
-int vm_uiomove (vm_map_t, vm_object_t, off_t, int, vm_offset_t, int *);
 void vm_freeze_copyopts (vm_object_t, vm_pindex_t, vm_pindex_t);
 int vm_map_stack (vm_map_t, vm_offset_t, vm_size_t, vm_prot_t, vm_prot_t, int);
 int vm_map_growstack (struct proc *p, vm_offset_t addr);
 int vmspace_swap_count (struct vmspace *vmspace);
 
+#ifdef ENABLE_VFS_IOOPT		/* Experimental support for zero-copy I/O */
+int vm_uiomove(vm_map_t, vm_object_t, off_t, int, vm_offset_t, int *);
+#endif
 #endif				/* _KERNEL */
 #endif				/* _VM_MAP_ */