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Commit 6568b08b authored by Dan Williams's avatar Dan Williams
Browse files

dax: introduce dax_operations 



Track a set of dax_operations per dax_device that can be set at
alloc_dax() time. These operations will be used to stop the abuse of
block_device_operations for communicating dax capabilities to
filesystems. It will also be used to replace the "pmem api" and move
pmem-specific cache maintenance, and other dax-driver-specific
filesystem-dax operations, to dax device methods. In particular this
allows us to stop abusing __copy_user_nocache(), via memcpy_to_pmem(),
with a driver specific replacement.

This is a standalone introduction of the operations. Follow on patches
convert each dax-driver and teach fs/dax.c to use ->direct_access() from
dax_operations instead of block_device_operations.

Suggested-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 72058005

drivers/dax/dax.h

+3 −1
Original line number Diff line number Diff line
@@ -13,7 +13,9 @@ 
#ifndef __DAX_H__

#define __DAX_H__

struct dax_device;

struct dax_device *alloc_dax(void *private, const char *host);

struct dax_operations;

struct dax_device *alloc_dax(void *private, const char *host,

		const struct dax_operations *ops);

void put_dax(struct dax_device *dax_dev);

bool dax_alive(struct dax_device *dax_dev);

void kill_dax(struct dax_device *dax_dev);

drivers/dax/device.c

+5 −1
Original line number Diff line number Diff line
@@ -645,7 +645,11 @@ struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region, 
		goto err_id;

	}



	dax_dev = alloc_dax(dev_dax, NULL);

	/*

	 * No 'host' or dax_operations since there is no access to this

	 * device outside of mmap of the resulting character device.

	 */

	dax_dev = alloc_dax(dev_dax, NULL, NULL);

	if (!dax_dev)

		goto err_dax;

drivers/dax/super.c

+5 −1
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/cdev.h>

#include <linux/hash.h>

#include <linux/slab.h>

#include <linux/dax.h>

#include <linux/fs.h>



static int nr_dax = CONFIG_NR_DEV_DAX;
@@ -61,6 +62,7 @@ struct dax_device { 
	const char *host;

	void *private;

	bool alive;

	const struct dax_operations *ops;

};



bool dax_alive(struct dax_device *dax_dev)
@@ -208,7 +210,8 @@ static void dax_add_host(struct dax_device *dax_dev, const char *host) 
	spin_unlock(&dax_host_lock);

}



struct dax_device *alloc_dax(void *private, const char *__host)

struct dax_device *alloc_dax(void *private, const char *__host,

		const struct dax_operations *ops)

{

	struct dax_device *dax_dev;

	const char *host;
@@ -229,6 +232,7 @@ struct dax_device *alloc_dax(void *private, const char *__host) 
		goto err_dev;



	dax_add_host(dax_dev, host);

	dax_dev->ops = ops;

	dax_dev->private = private;

	return dax_dev;

include/linux/dax.h

+10 −0
Original line number Diff line number Diff line
@@ -7,6 +7,16 @@ 
#include <asm/pgtable.h>



struct iomap_ops;

struct dax_device;

struct dax_operations {

	/*

	 * direct_access: translate a device-relative

	 * logical-page-offset into an absolute physical pfn. Return the

	 * number of pages available for DAX at that pfn.

	 */

	long (*direct_access)(struct dax_device *, pgoff_t, long,

			void **, pfn_t *);

};



int dax_read_lock(void);

void dax_read_unlock(int id);