[Devel] [PATCH 06/11] checkpoint: enable c/r for bsr driver

[Nathan Lynch]

BSR (Barrier Synchronization Register) is a IBM POWER-specific
register which can be used for fast synchronization on large systems
without cacheline bouncing.  This is a system-wide register and it is
not virtualized or context-switched.

Enable checkpoint and restart of BSR device mappings.  It is up to the
user/admin to initialize a job's BSR correctly when restarting or
migrating.

Signed-off-by: Nathan Lynch <ntl at pobox.com>
---
 drivers/char/bsr.c |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/drivers/char/bsr.c b/drivers/char/bsr.c
index 7fef305..e4ca911 100644
--- a/drivers/char/bsr.c
+++ b/drivers/char/bsr.c
@@ -24,6 +24,7 @@
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
 #include <linux/module.h>
+#include <linux/checkpoint.h>
 #include <linux/cdev.h>
 #include <linux/list.h>
 #include <linux/mm.h>
@@ -116,6 +117,12 @@ static struct device_attribute bsr_dev_attrs[] = {
 	__ATTR_NULL
 };
 
+#ifdef CONFIG_CHECKPOINT
+static const struct vm_operations_struct bsr_vm_ops = {
+       .checkpoint = device_vma_checkpoint,
+};
+#endif 
+
 static int bsr_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	unsigned long size   = vma->vm_end - vma->vm_start;
@@ -138,6 +145,9 @@ static int bsr_mmap(struct file *filp, struct vm_area_struct *vma)
 	if (ret)
 		return -EAGAIN;
 
+#ifdef CONFIG_CHECKPOINT
+	vma->vm_ops = &bsr_vm_ops;
+#endif
 	return 0;
 }
 
@@ -154,6 +164,9 @@ static const struct file_operations bsr_fops = {
 	.owner = THIS_MODULE,
 	.mmap  = bsr_mmap,
 	.open  = bsr_open,
+#ifdef CONFIG_CHECKPOINT
+	.checkpoint = generic_file_checkpoint,
+#endif
 };
 
 static void bsr_cleanup_devs(void)
-- 
1.7.2.2

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