[PATCH v5 03/16] device-dax: utilize new cdev_device_add helper function

[Logan Gunthorpe]

Replace the open coded registration of the cdev and dev with the
new device_add_cdev() helper. The helper replaces a common pattern by
taking the proper reference against the parent device and adding both
the cdev and the device.

Signed-off-by: Logan Gunthorpe <log...@deltatee.com>
Reviewed-by: Dan Williams <dan.j.willi...@intel.com>
Reviewed-by: Johannes Thumshirn <jthumsh...@suse.de>
---
 drivers/dax/dax.c | 18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index a5ed59a..e5f8555 100644
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -677,8 +677,6 @@ static void dax_dev_release(struct device *dev)
 
 static void kill_dax_dev(struct dax_dev *dax_dev)
 {
-       struct cdev *cdev = &dax_dev->cdev;
-
        /*
         * Note, rcu is not protecting the liveness of dax_dev, rcu is
         * ensuring that any fault handlers that might have seen
@@ -689,7 +687,6 @@ static void kill_dax_dev(struct dax_dev *dax_dev)
        dax_dev->alive = false;
        synchronize_rcu();
        unmap_mapping_range(dax_dev->inode->i_mapping, 0, 0, 1);
-       cdev_del(cdev);
 }
 
 static void unregister_dax_dev(void *dev)
@@ -699,7 +696,8 @@ static void unregister_dax_dev(void *dev)
        dev_dbg(dev, "%s\n", __func__);
 
        kill_dax_dev(dax_dev);
-       device_unregister(dev);
+       cdev_device_del(&dax_dev->cdev, dev);
+       put_device(dev);
 }
 
 struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
@@ -750,18 +748,13 @@ struct dax_dev *devm_create_dax_dev(struct dax_region 
*dax_region,
                goto err_inode;
        }
 
-       /* device_initialize() so cdev can reference kobj parent */
+       /* from here on we're committed to teardown via dax_dev_release() */
        device_initialize(dev);
 
        cdev = &dax_dev->cdev;
        cdev_init(cdev, &dax_fops);
        cdev->owner = parent->driver->owner;
-       cdev->kobj.parent = &dev->kobj;
-       rc = cdev_add(&dax_dev->cdev, dev_t, 1);
-       if (rc)
-               goto err_cdev;
 
-       /* from here on we're committed to teardown via dax_dev_release() */
        dax_dev->num_resources = count;
        dax_dev->alive = true;
        dax_dev->region = dax_region;
@@ -773,7 +766,8 @@ struct dax_dev *devm_create_dax_dev(struct dax_region 
*dax_region,
        dev->groups = dax_attribute_groups;
        dev->release = dax_dev_release;
        dev_set_name(dev, "dax%d.%d", dax_region->id, dax_dev->id);
-       rc = device_add(dev);
+
+       rc = cdev_device_add(cdev, dev);
        if (rc) {
                kill_dax_dev(dax_dev);
                put_device(dev);
@@ -786,8 +780,6 @@ struct dax_dev *devm_create_dax_dev(struct dax_region 
*dax_region,
 
        return dax_dev;
 
- err_cdev:
-       iput(dax_dev->inode);
  err_inode:
        ida_simple_remove(&dax_minor_ida, minor);
  err_minor:
-- 
2.1.4