dax: refactor dax-fs into a generic provider of 'struct dax_device' instances
We want dax capable drivers to be able to publish a set of dax
operations [1]. However, we do not want to further abuse block_devices
to advertise these operations. Instead we will attach these operations
to a dax device and add a lookup mechanism to go from block device path
to a dax device. A dax capable driver like pmem or brd is responsible
for registering a dax device, alongside a block device, and then a dax
capable filesystem is responsible for retrieving the dax device by path
name if it wants to call dax_operations.
For now, we refactor the dax pseudo-fs to be a generic facility, rather
than an implementation detail, of the device-dax use case. Where a "dax
device" is just an inode + dax infrastructure, and "Device DAX" is a
mapping service layered on top of that base 'struct dax_device'.
"Filesystem DAX" is then a mapping service that layers a filesystem on
top of that same base device. Filesystem DAX is associated with a
block_device for now, but perhaps directly to a dax device in the
future, or for new pmem-only filesystems.
[1]: https://lkml.org/lkml/2017/1/19/880
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dax/dax.h b/drivers/dax/dax.h
index ea176d8..2472d9d 100644
--- a/drivers/dax/dax.h
+++ b/drivers/dax/dax.h
@@ -1,5 +1,5 @@
/*
- * Copyright(c) 2016 Intel Corporation. All rights reserved.
+ * Copyright(c) 2016 - 2017 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
@@ -12,14 +12,12 @@
*/
#ifndef __DAX_H__
#define __DAX_H__
-struct device;
-struct dev_dax;
-struct resource;
-struct dax_region;
-void dax_region_put(struct dax_region *dax_region);
-struct dax_region *alloc_dax_region(struct device *parent,
- int region_id, struct resource *res, unsigned int align,
- void *addr, unsigned long flags);
-struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
- struct resource *res, int count);
+struct dax_device;
+struct dax_device *alloc_dax(void *private);
+void put_dax(struct dax_device *dax_dev);
+bool dax_alive(struct dax_device *dax_dev);
+void kill_dax(struct dax_device *dax_dev);
+struct dax_device *inode_dax(struct inode *inode);
+struct inode *dax_inode(struct dax_device *dax_dev);
+void *dax_get_private(struct dax_device *dax_dev);
#endif /* __DAX_H__ */