From f7f2addc5c990ddaac48c4f1a6f299710baf86ca Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Fri, 4 Nov 2011 13:56:56 -0400
Subject: [PATCH] Add test-case to do wb->wc and vice-versa forever..

---
 root_image/drivers/Makefile            |  1 +
 root_image/drivers/wb_to_wc/Makefile   | 37 ++++++++++++++++++
 root_image/drivers/wb_to_wc/wb_to_wc.c | 53 ++++++++++++++++++++++++++
 3 files changed, 91 insertions(+)
 create mode 100644 root_image/drivers/wb_to_wc/Makefile
 create mode 100644 root_image/drivers/wb_to_wc/wb_to_wc.c

diff --git a/root_image/drivers/Makefile b/root_image/drivers/Makefile
index 3c1b76a..6dbdb75 100644
--- a/root_image/drivers/Makefile
+++ b/root_image/drivers/Makefile
@@ -1,4 +1,5 @@
 obj-m += dump/
+obj-m += wb_to_wc/
 
 .PHONY:	distclean
 distclean:	clean
diff --git a/root_image/drivers/wb_to_wc/Makefile b/root_image/drivers/wb_to_wc/Makefile
new file mode 100644
index 0000000..cc280a6
--- /dev/null
+++ b/root_image/drivers/wb_to_wc/Makefile
@@ -0,0 +1,37 @@
+# Comment/uncomment the following line to disable/enable debugging
+#DEBUG = y
+
+# Add your debugging flag (or not) to CFLAGS
+ifeq ($(DEBUG),y)
+  DEBFLAGS = -O -g # "-O" is needed to expand inlines
+else
+  DEBFLAGS = -O2
+endif
+
+EXTRA_CFLAGS += $(DEBFLAGS) -I$(LDDINCDIR)
+
+ifneq ($(KERNELRELEASE),)
+# call from kernel build system
+
+obj-m	:= wb_to_wc.o
+
+else
+
+KERNELDIR ?= /lib/modules/$(shell uname -r)/build
+PWD       := $(shell pwd)
+
+default:
+	$(MAKE) -C $(KERNELDIR) M=$(PWD) LDDINCDIR=$(PWD)/../include modules
+
+endif
+
+clean:
+	rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions
+
+depend .depend dep:
+	$(CC) $(CFLAGS) -M *.c > .depend
+
+
+ifeq (.depend,$(wildcard .depend))
+include .depend
+endif
diff --git a/root_image/drivers/wb_to_wc/wb_to_wc.c b/root_image/drivers/wb_to_wc/wb_to_wc.c
new file mode 100644
index 0000000..cd2439a
--- /dev/null
+++ b/root_image/drivers/wb_to_wc/wb_to_wc.c
@@ -0,0 +1,53 @@
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#define WB_TO_WC  "0.1"
+
+MODULE_AUTHOR("Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>");
+MODULE_DESCRIPTION("wb_to_wc_and_back");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(WB_TO_WC);
+
+#define MAX_PAGES 20
+static int thread(void *arg)
+{
+	struct page *a[MAX_PAGES];
+	unsigned int i, j;
+	do {
+		for (j = 0, i = 0;i < MAX_PAGES; i++, j++) {
+			a[i] = alloc_page(GFP_KERNEL);
+			if (!a[i])
+				break;
+		}
+		set_pages_array_wc(a, j);
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout_interruptible(HZ);
+		for (i = 0; i < j; i++) {
+			unsigned long *addr = page_address(a[i]);
+			if (addr) {
+				memset(addr, 0xc2, PAGE_SIZE);
+			}
+		}
+		set_pages_array_wb(a, j);
+		for (i = 0; i< MAX_PAGES; i++) {
+			if (a[i])
+				__free_page(a[i]);
+			a[i] = NULL;
+		}
+	} while (!kthread_should_stop());
+	return 0;
+}
+static struct task_struct *t;
+static int __init wb_to_wc_init(void)
+{
+	t = kthread_run(thread, NULL, "wb_to_wc_and_back");
+	return 0;
+}
+static void __exit wb_to_wc_exit(void)
+{
+	if (t)
+		kthread_stop(t);
+}
+module_init(wb_to_wc_init);
+module_exit(wb_to_wc_exit);
-- 
2.39.5