1 files changed, 66 insertions, 0 deletions
diff --git a/device/blkio.c b/device/blkio.c
new file mode 100644
index 0000000..0dfa33c
--- /dev/null
+++ b/device/blkio.c
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+/* 
+ * Mach Operating System
+ * Copyright (c) 1991,1990,1989 Carnegie Mellon University
+ * All Rights Reserved.
+ * 
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+ * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ * 
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ * 
+ * any improvements or extensions that they make and grant Carnegie Mellon
+ * the rights to redistribute these changes.
+ */
+/*
+ *	Author: David B. Golub, Carnegie Mellon University
+ *	Date: 	7/89
+ *
+ * 	Block IO driven from generic kernel IO interface.
+ */
+#include <mach/kern_return.h>
+
+#include <device/blkio.h>
+#include <device/buf.h>
+#include <device/param.h>
+#include <device/device_types.h>
+#include <device/io_req.h>
+#include <device/ds_routines.h>
+
+
+/*
+ * 'standard' max_count routine.  VM continuations mean that this
+ * code can cope with arbitrarily-sized write operations (they won't be
+ * atomic, but any caller that cares will do the op synchronously).
+ */
+#define MAX_PHYS        (256 * 1024)
+
+void minphys(io_req_t ior)
+{
+	if ((ior->io_op & (IO_WRITE | IO_READ | IO_OPEN)) == IO_WRITE)
+	    return;
+
+        if (ior->io_count > MAX_PHYS)
+            ior->io_count = MAX_PHYS;
+}
+
+/*
+ * Dummy routine placed in device switch entries to indicate that
+ * block device may be mapped.
+ */
+vm_offset_t block_io_mmap(dev_t dev, vm_offset_t off, int prot)
+{
+	return (0);
+}
+