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Commit 7b6be844 authored by Dan Williams's avatar Dan Williams
Browse files

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: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 5f0694b3

drivers/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -71,7 +71,7 @@ obj-$(CONFIG_PARPORT) += parport/ 
obj-$(CONFIG_NVM)		+= lightnvm/

obj-y				+= base/ block/ misc/ mfd/ nfc/

obj-$(CONFIG_LIBNVDIMM)		+= nvdimm/

obj-$(CONFIG_DEV_DAX)		+= dax/

obj-$(CONFIG_DAX)		+= dax/

obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf/

obj-$(CONFIG_NUBUS)		+= nubus/

obj-y				+= macintosh/

drivers/dax/Kconfig

+7 −3
Original line number Diff line number Diff line 
menuconfig DEV_DAX

menuconfig DAX

	tristate "DAX: direct access to differentiated memory"

	select SRCU

	default m if NVDIMM_DAX



if DAX



config DEV_DAX

	tristate "Device DAX: direct access mapping device"

	depends on TRANSPARENT_HUGEPAGE

	select SRCU

	help

	  Support raw access to differentiated (persistence, bandwidth,

	  latency...) memory via an mmap(2) capable character
@@ -11,7 +16,6 @@ menuconfig DEV_DAX 
	  baseline memory pool.  Mappings of a /dev/daxX.Y device impose

	  restrictions that make the mapping behavior deterministic.



if DEV_DAX



config DEV_DAX_PMEM

	tristate "PMEM DAX: direct access to persistent memory"

drivers/dax/Makefile

+4 −1
Original line number Diff line number Diff line 
obj-$(CONFIG_DEV_DAX) += dax.o

obj-$(CONFIG_DAX) += dax.o

obj-$(CONFIG_DEV_DAX) += device_dax.o

obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o



dax-y := super.o

dax_pmem-y := pmem.o

device_dax-y := device.o

drivers/dax/dax.h

+9 −11
Original line number Diff line number Diff line 
/*

 * 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__ */

drivers/dax/device-dax.h

0 → 100644
+25 −0
Original line number Diff line number Diff line 
/*

 * Copyright(c) 2016 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

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 */

#ifndef __DEVICE_DAX_H__

#define __DEVICE_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);

#endif /* __DEVICE_DAX_H__ */