1 files changed, 23 insertions, 4 deletions

diff --git a/fs/char_dev.c b/fs/char_dev.c
index 3f152b92a94..f77f7702fab 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -368,6 +368,7 @@ void cdev_put(struct cdev *p)
  */
 static int chrdev_open(struct inode *inode, struct file *filp)
 {
+	const struct file_operations *fops;
 	struct cdev *p;
 	struct cdev *new = NULL;
 	int ret = 0;
@@ -400,10 +401,11 @@ static int chrdev_open(struct inode *inode, struct file *filp)
 		return ret;
 
 	ret = -ENXIO;
-	filp->f_op = fops_get(p->ops);
-	if (!filp->f_op)
+	fops = fops_get(p->ops);
+	if (!fops)
 		goto out_cdev_put;
 
+	replace_fops(filp, fops);
 	if (filp->f_op->open) {
 		ret = filp->f_op->open(inode, filp);
 		if (ret)
@@ -471,9 +473,19 @@ static int exact_lock(dev_t dev, void *data)
  */
 int cdev_add(struct cdev *p, dev_t dev, unsigned count)
 {
+	int error;
+
 	p->dev = dev;
 	p->count = count;
-	return kobj_map(cdev_map, dev, count, NULL, exact_match, exact_lock, p);
+
+	error = kobj_map(cdev_map, dev, count, NULL,
+			 exact_match, exact_lock, p);
+	if (error)
+		return error;
+
+	kobject_get(p->kobj.parent);
+
+	return 0;
 }
 
 static void cdev_unmap(dev_t dev, unsigned count)
@@ -498,14 +510,20 @@ void cdev_del(struct cdev *p)
 static void cdev_default_release(struct kobject *kobj)
 {
 	struct cdev *p = container_of(kobj, struct cdev, kobj);
+	struct kobject *parent = kobj->parent;
+
 	cdev_purge(p);
+	kobject_put(parent);
 }
 
 static void cdev_dynamic_release(struct kobject *kobj)
 {
 	struct cdev *p = container_of(kobj, struct cdev, kobj);
+	struct kobject *parent = kobj->parent;
+
 	cdev_purge(p);
 	kfree(p);
+	kobject_put(parent);
 }
 
 static struct kobj_type ktype_cdev_default = {
@@ -558,7 +576,8 @@ static struct kobject *base_probe(dev_t dev, int *part, void *data)
 void __init chrdev_init(void)
 {
 	cdev_map = kobj_map_init(base_probe, &chrdevs_lock);
-	bdi_init(&directly_mappable_cdev_bdi);
+	if (bdi_init(&directly_mappable_cdev_bdi))
+		panic("Failed to init directly mappable cdev bdi");
 }