device-dax: Introduce bus + driver model
In support of multiple device-dax instances per device-dax-region and
allowing the 'kmem' driver to attach to dax-instances instead of the
current device-node access, convert the dax sub-system from a class to a
bus. Recall that the kmem driver takes reserved / special purpose
memories and assigns them to be managed by the core-mm.
Aside from the fact the device-dax instances are registered and probed
on a bus, two other lifetime-management changes are made:
1/ Delay attaching a cdev until driver probe time
2/ A new run_dax() helper is introduced to allow restoring dax-operation
after a kill_dax() event. So, at driver ->probe() time we run_dax()
and at ->remove() time we kill_dax() and invalidate all mappings.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 0ecc1a2..ccb22d8d 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -366,11 +366,15 @@ void kill_dax(struct dax_device *dax_dev)
spin_lock(&dax_host_lock);
hlist_del_init(&dax_dev->list);
spin_unlock(&dax_host_lock);
-
- dax_dev->private = NULL;
}
EXPORT_SYMBOL_GPL(kill_dax);
+void run_dax(struct dax_device *dax_dev)
+{
+ set_bit(DAXDEV_ALIVE, &dax_dev->flags);
+}
+EXPORT_SYMBOL_GPL(run_dax);
+
static struct inode *dax_alloc_inode(struct super_block *sb)
{
struct dax_device *dax_dev;
@@ -585,6 +589,8 @@ EXPORT_SYMBOL_GPL(dax_inode);
void *dax_get_private(struct dax_device *dax_dev)
{
+ if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags))
+ return NULL;
return dax_dev->private;
}
EXPORT_SYMBOL_GPL(dax_get_private);
@@ -598,7 +604,7 @@ static void init_once(void *_dax_dev)
inode_init_once(inode);
}
-static int __dax_fs_init(void)
+static int dax_fs_init(void)
{
int rc;
@@ -630,35 +636,45 @@ static int __dax_fs_init(void)
return rc;
}
-static void __dax_fs_exit(void)
+static void dax_fs_exit(void)
{
kern_unmount(dax_mnt);
unregister_filesystem(&dax_fs_type);
kmem_cache_destroy(dax_cache);
}
-static int __init dax_fs_init(void)
+static int __init dax_core_init(void)
{
int rc;
- rc = __dax_fs_init();
+ rc = dax_fs_init();
if (rc)
return rc;
rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax");
if (rc)
- __dax_fs_exit();
- return rc;
+ goto err_chrdev;
+
+ rc = dax_bus_init();
+ if (rc)
+ goto err_bus;
+ return 0;
+
+err_bus:
+ unregister_chrdev_region(dax_devt, MINORMASK+1);
+err_chrdev:
+ dax_fs_exit();
+ return 0;
}
-static void __exit dax_fs_exit(void)
+static void __exit dax_core_exit(void)
{
unregister_chrdev_region(dax_devt, MINORMASK+1);
ida_destroy(&dax_minor_ida);
- __dax_fs_exit();
+ dax_fs_exit();
}
MODULE_AUTHOR("Intel Corporation");
MODULE_LICENSE("GPL v2");
-subsys_initcall(dax_fs_init);
-module_exit(dax_fs_exit);
+subsys_initcall(dax_core_init);
+module_exit(dax_core_exit);