Use the Block Transfer Engine in the Altix SN2 SHub for background
zeroing

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.16-rc1-mm3/arch/ia64/sn/kernel/bte.c
===================================================================
--- linux-2.6.16-rc1-mm3.orig/arch/ia64/sn/kernel/bte.c	2006-01-16 23:44:47.000000000 -0800
+++ linux-2.6.16-rc1-mm3/arch/ia64/sn/kernel/bte.c	2006-01-26 22:16:29.000000000 -0800
@@ -3,7 +3,9 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (c) 2000-2005 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2000-2006 Silicon Graphics, Inc.  All Rights Reserved.
+ *
+ * Support for zeroing pages, Christoph Lameter, SGI, January 2006.
  */
 
 #include <linux/config.h>
@@ -20,6 +22,7 @@
 #include <linux/bootmem.h>
 #include <linux/string.h>
 #include <linux/sched.h>
+#include <linux/mm.h>
 
 #include <asm/sn/bte.h>
 
@@ -473,5 +476,20 @@ void bte_init_node(nodepda_t * mynodepda
 		mynodepda->bte_if[i].cleanup_active = 0;
 		mynodepda->bte_if[i].bh_error = 0;
 	}
+}
+
+static int bte_zero_func(void *p, unsigned long len)
+{
+	if (len >= BTE_MAX_XFER || system_state != SYSTEM_RUNNING)
+		return EINVAL;
+
+	return bte_zero(ia64_tpa(p), len, 0, NULL);
+}
+
+static struct zero_driver bte_bzero = {
+	.zero_func = bte_zero_func,
+};
 
+void sn_bte_bzero_init(void) {
+	register_zero_driver(&bte_bzero);
 }
Index: linux-2.6.16-rc1-mm3/arch/ia64/sn/kernel/setup.c
===================================================================
--- linux-2.6.16-rc1-mm3.orig/arch/ia64/sn/kernel/setup.c	2006-01-26 22:14:12.000000000 -0800
+++ linux-2.6.16-rc1-mm3/arch/ia64/sn/kernel/setup.c	2006-01-26 22:15:42.000000000 -0800
@@ -386,6 +386,7 @@ void __init sn_setup(char **cmdline_p)
 	long status, ticks_per_sec, drift;
 	u32 version = sn_sal_rev();
 	extern void sn_cpu_init(void);
+	extern void sn_bte_bzero_init(void);
 
 	ia64_sn_plat_set_error_handling_features();	// obsolete
 	ia64_sn_set_os_feature(OSF_MCA_SLV_TO_OS_INIT_SLV);
@@ -489,6 +490,7 @@ void __init sn_setup(char **cmdline_p)
 	screen_info = sn_screen_info;
 
 	sn_timer_init();
+	sn_bte_bzero_init();
 
 	/*
 	 * set pm_power_off to a SAL call to allow