[PATCH v2 03/16] device-dax: utilize new cdev_device_add helper function

Logan Gunthorpe
2017-02-26T06:38:04Z

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 <logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>
---
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 b62a52f..e60b519 100644
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -632,8 +632,6 @@ 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
@@ -644,7 +642,6 @@ 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)
@@ -654,7 +651,8 @@ 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,
@@ -705,18 +703,13 @@ 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;
@@ -728,7 +721,8 @@ 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);
@@ -741,8 +735,6 @@ 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