From c50fe92b8dc1b0867eaaeee365f6b5d0f4ff5217 Mon Sep 17 00:00:00 2001
From: Alan Cox <alc@FreeBSD.org>
Date: Sun, 5 May 2002 22:42:40 +0000
Subject: [PATCH]  o Condition the compilation of uiomoveco() and vm_uiomove() 
   on ENABLE_VFS_IOOPT.  o Add a comment to the effect that this code is
 experimental    support for zero-copy I/O.

---
 sys/kern/kern_subr.c | 10 +++++++---
 sys/sys/uio.h        |  2 ++
 sys/vm/vm_map.c      |  4 ++++
 sys/vm/vm_map.h      |  4 +++-
 4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/sys/kern/kern_subr.c b/sys/kern/kern_subr.c
index 9f2ede2d4c95..73aa75bbef89 100644
--- a/sys/kern/kern_subr.c
+++ b/sys/kern/kern_subr.c
@@ -134,6 +134,10 @@ uiomove(cp, n, uio)
 	return (error);
 }
 
+#ifdef ENABLE_VFS_IOOPT
+/*
+ * Experimental support for zero-copy I/O
+ */
 int
 uiomoveco(cp, n, uio, obj)
 	caddr_t cp;
@@ -207,8 +211,9 @@ uiomoveco(cp, n, uio, obj)
 	return (0);
 }
 
-#ifdef ENABLE_VFS_IOOPT
-
+/*
+ * Experimental support for zero-copy I/O
+ */
 int
 uioread(n, uio, obj, nread)
 	int n;
@@ -274,7 +279,6 @@ uioread(n, uio, obj, nread)
 	}
 	return error;
 }
-
 #endif
 
 /*
diff --git a/sys/sys/uio.h b/sys/sys/uio.h
index e09ca3fa023e..59e54f185426 100644
--- a/sys/sys/uio.h
+++ b/sys/sys/uio.h
@@ -86,8 +86,10 @@ struct vm_object;
 
 void	uio_yield(void);
 int	uiomove(caddr_t, int, struct uio *);
+#ifdef ENABLE_VFS_IOOPT		/* Experimental support for zero-copy I/O */
 int	uiomoveco(caddr_t, int, struct uio *, struct vm_object *);
 int	uioread(int, struct uio *, struct vm_object *, int *);
+#endif
 int	copyinfrom(const void *src, void *dst, size_t len, int seg);
 int	copyinstrfrom(const void *src, void *dst, size_t len,
 	    size_t *copied, int seg);
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_ */