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dax: refactor dax-fs into a generic provider of 'struct dax_device' instances

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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>
This commit is contained in:
Dan Williams 2017-04-11 09:49:49 -07:00
parent 5f0694b300
commit 7b6be8444e
10 changed files with 405 additions and 218 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/Makefile
View File

@ -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/

12
drivers/dax/Kconfig
View File

@ -1,8 +1,13 @@
menuconfig DEV_DAX
menuconfig DAX
tristate "DAX: direct access to differentiated memory"
default m if NVDIMM_DAX
depends on TRANSPARENT_HUGEPAGE
select SRCU
default m if NVDIMM_DAX
if DAX
config DEV_DAX
tristate "Device DAX: direct access mapping device"
depends on TRANSPARENT_HUGEPAGE
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"

5
drivers/dax/Makefile
View File

@ -1,4 +1,7 @@
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

20
drivers/dax/dax.h
View File

@ -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__ */

25
drivers/dax/device-dax.h Normal file
View File

@ -0,0 +1,25 @@
/*
* 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__ */

241
drivers/dax/dax.c → drivers/dax/device.c
View File

@ -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
@ -13,10 +13,7 @@
#include <linux/pagemap.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/magic.h>
#include <linux/mount.h>
#include <linux/pfn_t.h>
#include <linux/hash.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include <linux/dax.h>
@ -24,16 +21,7 @@
#include <linux/mm.h>
#include "dax.h"
static dev_t dax_devt;
DEFINE_STATIC_SRCU(dax_srcu);
static struct class *dax_class;
static DEFINE_IDA(dax_minor_ida);
static int nr_dax = CONFIG_NR_DEV_DAX;
module_param(nr_dax, int, S_IRUGO);
static struct vfsmount *dax_mnt;
static struct kmem_cache *dax_cache __read_mostly;
static struct super_block *dax_superblock __read_mostly;
MODULE_PARM_DESC(nr_dax, "max number of device-dax instances");
/**
* struct dax_region - mapping infrastructure for dax devices
@ -59,19 +47,16 @@ struct dax_region {
/**
* struct dev_dax - instance data for a subdivision of a dax region
* @region - parent region
* @dev - device backing the character device
* @cdev - core chardev data
* @alive - !alive + srcu grace period == no new mappings can be established
* @dax_dev - core dax functionality
* @dev - device core
* @id - child id in the region
* @num_resources - number of physical address extents in this device
* @res - array of physical address ranges
*/
struct dev_dax {
struct dax_region *region;
struct inode *inode;
struct dax_device *dax_dev;
struct device dev;
struct cdev cdev;
bool alive;
int id;
int num_resources;
struct resource res[0];
@ -144,117 +129,6 @@ static const struct attribute_group *dax_region_attribute_groups[] = {
NULL,
};
static struct inode *dax_alloc_inode(struct super_block *sb)
{
return kmem_cache_alloc(dax_cache, GFP_KERNEL);
}
static void dax_i_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
kmem_cache_free(dax_cache, inode);
}
static void dax_destroy_inode(struct inode *inode)
{
call_rcu(&inode->i_rcu, dax_i_callback);
}
static const struct super_operations dax_sops = {
.statfs = simple_statfs,
.alloc_inode = dax_alloc_inode,
.destroy_inode = dax_destroy_inode,
.drop_inode = generic_delete_inode,
};
static struct dentry *dax_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC);
}
static struct file_system_type dax_type = {
.name = "dax",
.mount = dax_mount,
.kill_sb = kill_anon_super,
};
static int dax_test(struct inode *inode, void *data)
{
return inode->i_cdev == data;
}
static int dax_set(struct inode *inode, void *data)
{
inode->i_cdev = data;
return 0;
}
static struct inode *dax_inode_get(struct cdev *cdev, dev_t devt)
{
struct inode *inode;
inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31),
dax_test, dax_set, cdev);
if (!inode)
return NULL;
if (inode->i_state & I_NEW) {
inode->i_mode = S_IFCHR;
inode->i_flags = S_DAX;
inode->i_rdev = devt;
mapping_set_gfp_mask(&inode->i_data, GFP_USER);
unlock_new_inode(inode);
}
return inode;
}
static void init_once(void *inode)
{
inode_init_once(inode);
}
static int dax_inode_init(void)
{
int rc;
dax_cache = kmem_cache_create("dax_cache", sizeof(struct inode), 0,
(SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD|SLAB_ACCOUNT),
init_once);
if (!dax_cache)
return -ENOMEM;
rc = register_filesystem(&dax_type);
if (rc)
goto err_register_fs;
dax_mnt = kern_mount(&dax_type);
if (IS_ERR(dax_mnt)) {
rc = PTR_ERR(dax_mnt);
goto err_mount;
}
dax_superblock = dax_mnt->mnt_sb;
return 0;
err_mount:
unregister_filesystem(&dax_type);
err_register_fs:
kmem_cache_destroy(dax_cache);
return rc;
}
static void dax_inode_exit(void)
{
kern_unmount(dax_mnt);
unregister_filesystem(&dax_type);
kmem_cache_destroy(dax_cache);
}
static void dax_region_free(struct kref *kref)
{
struct dax_region *dax_region;
@ -363,7 +237,7 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
struct device *dev = &dev_dax->dev;
unsigned long mask;
if (!dev_dax->alive)
if (!dax_alive(dev_dax->dax_dev))
return -ENXIO;
/* prevent private mappings from being established */
@ -582,7 +456,7 @@ static int dev_dax_huge_fault(struct vm_fault *vmf,
? "write" : "read",
vmf->vma->vm_start, vmf->vma->vm_end, pe_size);
id = srcu_read_lock(&dax_srcu);
id = dax_read_lock();
switch (pe_size) {
case PE_SIZE_PTE:
rc = __dev_dax_pte_fault(dev_dax, vmf);
@ -596,7 +470,7 @@ static int dev_dax_huge_fault(struct vm_fault *vmf,
default:
rc = VM_FAULT_SIGBUS;
}
srcu_read_unlock(&dax_srcu, id);
dax_read_unlock(id);
return rc;
}
@ -614,11 +488,17 @@ static const struct vm_operations_struct dax_vm_ops = {
static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct dev_dax *dev_dax = filp->private_data;
int rc;
int rc, id;
dev_dbg(&dev_dax->dev, "%s\n", __func__);
/*
* We lock to check dax_dev liveness and will re-check at
* fault time.
*/
id = dax_read_lock();
rc = check_vma(dev_dax, vma, __func__);
dax_read_unlock(id);
if (rc)
return rc;
@ -664,12 +544,13 @@ static unsigned long dax_get_unmapped_area(struct file *filp,
static int dax_open(struct inode *inode, struct file *filp)
{
struct dev_dax *dev_dax;
struct dax_device *dax_dev = inode_dax(inode);
struct inode *__dax_inode = dax_inode(dax_dev);
struct dev_dax *dev_dax = dax_get_private(dax_dev);
dev_dax = container_of(inode->i_cdev, struct dev_dax, cdev);
dev_dbg(&dev_dax->dev, "%s\n", __func__);
inode->i_mapping = dev_dax->inode->i_mapping;
inode->i_mapping->host = dev_dax->inode;
inode->i_mapping = __dax_inode->i_mapping;
inode->i_mapping->host = __dax_inode;
filp->f_mapping = inode->i_mapping;
filp->private_data = dev_dax;
inode->i_flags = S_DAX;
@ -698,36 +579,34 @@ static void dev_dax_release(struct device *dev)
{
struct dev_dax *dev_dax = to_dev_dax(dev);
struct dax_region *dax_region = dev_dax->region;
struct dax_device *dax_dev = dev_dax->dax_dev;
ida_simple_remove(&dax_region->ida, dev_dax->id);
ida_simple_remove(&dax_minor_ida, MINOR(dev->devt));
dax_region_put(dax_region);
iput(dev_dax->inode);
put_dax(dax_dev);
kfree(dev_dax);
}
static void kill_dev_dax(struct dev_dax *dev_dax)
{
/*
* Note, rcu is not protecting the liveness of dev_dax, rcu is
* ensuring that any fault handlers that might have seen
* dev_dax->alive == true, have completed. Any fault handlers
* that start after synchronize_srcu() has started will abort
* upon seeing dev_dax->alive == false.
*/
dev_dax->alive = false;
synchronize_srcu(&dax_srcu);
unmap_mapping_range(dev_dax->inode->i_mapping, 0, 0, 1);
struct dax_device *dax_dev = dev_dax->dax_dev;
struct inode *inode = dax_inode(dax_dev);
kill_dax(dax_dev);
unmap_mapping_range(inode->i_mapping, 0, 0, 1);
}
static void unregister_dev_dax(void *dev)
{
struct dev_dax *dev_dax = to_dev_dax(dev);
struct dax_device *dax_dev = dev_dax->dax_dev;
struct inode *inode = dax_inode(dax_dev);
struct cdev *cdev = inode->i_cdev;
dev_dbg(dev, "%s\n", __func__);
kill_dev_dax(dev_dax);
cdev_device_del(&dev_dax->cdev, dev);
cdev_device_del(cdev, dev);
put_device(dev);
}
@ -735,11 +614,12 @@ struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
struct resource *res, int count)
{
struct device *parent = dax_region->dev;
struct dax_device *dax_dev;
struct dev_dax *dev_dax;
int rc = 0, minor, i;
struct inode *inode;
struct device *dev;
struct cdev *cdev;
dev_t dev_t;
int rc = 0, i;
dev_dax = kzalloc(sizeof(*dev_dax) + sizeof(*res) * count, GFP_KERNEL);
if (!dev_dax)
@ -765,33 +645,25 @@ struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
goto err_id;
}
minor = ida_simple_get(&dax_minor_ida, 0, 0, GFP_KERNEL);
if (minor < 0) {
rc = minor;
goto err_minor;
}
dax_dev = alloc_dax(dev_dax);
if (!dax_dev)
goto err_dax;
dev_t = MKDEV(MAJOR(dax_devt), minor);
/* from here on we're committed to teardown via dax_dev_release() */
dev = &dev_dax->dev;
dev_dax->inode = dax_inode_get(&dev_dax->cdev, dev_t);
if (!dev_dax->inode) {
rc = -ENOMEM;
goto err_inode;
}
/* from here on we're committed to teardown via dev_dax_release() */
device_initialize(dev);
cdev = &dev_dax->cdev;
inode = dax_inode(dax_dev);
cdev = inode->i_cdev;
cdev_init(cdev, &dax_fops);
cdev->owner = parent->driver->owner;
dev_dax->num_resources = count;
dev_dax->alive = true;
dev_dax->dax_dev = dax_dev;
dev_dax->region = dax_region;
kref_get(&dax_region->kref);
dev->devt = dev_t;
dev->devt = inode->i_rdev;
dev->class = dax_class;
dev->parent = parent;
dev->groups = dax_attribute_groups;
@ -811,9 +683,7 @@ struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
return dev_dax;
err_inode:
ida_simple_remove(&dax_minor_ida, minor);
err_minor:
err_dax:
ida_simple_remove(&dax_region->ida, dev_dax->id);
err_id:
kfree(dev_dax);
@ -824,38 +694,13 @@ EXPORT_SYMBOL_GPL(devm_create_dev_dax);
static int __init dax_init(void)
{
int rc;
rc = dax_inode_init();
if (rc)
return rc;
nr_dax = max(nr_dax, 256);
rc = alloc_chrdev_region(&dax_devt, 0, nr_dax, "dax");
if (rc)
goto err_chrdev;
dax_class = class_create(THIS_MODULE, "dax");
if (IS_ERR(dax_class)) {
rc = PTR_ERR(dax_class);
goto err_class;
}
return 0;
err_class:
unregister_chrdev_region(dax_devt, nr_dax);
err_chrdev:
dax_inode_exit();
return rc;
return PTR_ERR_OR_ZERO(dax_class);
}
static void __exit dax_exit(void)
{
class_destroy(dax_class);
unregister_chrdev_region(dax_devt, nr_dax);
ida_destroy(&dax_minor_ida);
dax_inode_exit();
}
MODULE_AUTHOR("Intel Corporation");

2
drivers/dax/pmem.c
View File

@ -16,7 +16,7 @@
#include <linux/pfn_t.h>
#include "../nvdimm/pfn.h"
#include "../nvdimm/nd.h"
#include "dax.h"
#include "device-dax.h"
struct dax_pmem {
struct device *dev;

303
drivers/dax/super.c Normal file
View File

@ -0,0 +1,303 @@
/*
* Copyright(c) 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
* 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.
*/
#include <linux/pagemap.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/magic.h>
#include <linux/cdev.h>
#include <linux/hash.h>
#include <linux/slab.h>
#include <linux/fs.h>
static int nr_dax = CONFIG_NR_DEV_DAX;
module_param(nr_dax, int, S_IRUGO);
MODULE_PARM_DESC(nr_dax, "max number of dax device instances");
static dev_t dax_devt;
DEFINE_STATIC_SRCU(dax_srcu);
static struct vfsmount *dax_mnt;
static DEFINE_IDA(dax_minor_ida);
static struct kmem_cache *dax_cache __read_mostly;
static struct super_block *dax_superblock __read_mostly;
int dax_read_lock(void)
{
return srcu_read_lock(&dax_srcu);
}
EXPORT_SYMBOL_GPL(dax_read_lock);
void dax_read_unlock(int id)
{
srcu_read_unlock(&dax_srcu, id);
}
EXPORT_SYMBOL_GPL(dax_read_unlock);
/**
* struct dax_device - anchor object for dax services
* @inode: core vfs
* @cdev: optional character interface for "device dax"
* @private: dax driver private data
* @alive: !alive + rcu grace period == no new operations / mappings
*/
struct dax_device {
struct inode inode;
struct cdev cdev;
void *private;
bool alive;
};
bool dax_alive(struct dax_device *dax_dev)
{
lockdep_assert_held(&dax_srcu);
return dax_dev->alive;
}
EXPORT_SYMBOL_GPL(dax_alive);
/*
* Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring
* that any fault handlers or operations that might have seen
* dax_alive(), have completed. Any operations that start after
* synchronize_srcu() has run will abort upon seeing !dax_alive().
*/
void kill_dax(struct dax_device *dax_dev)
{
if (!dax_dev)
return;
dax_dev->alive = false;
synchronize_srcu(&dax_srcu);
dax_dev->private = NULL;
}
EXPORT_SYMBOL_GPL(kill_dax);
static struct inode *dax_alloc_inode(struct super_block *sb)
{
struct dax_device *dax_dev;
dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL);
return &dax_dev->inode;
}
static struct dax_device *to_dax_dev(struct inode *inode)
{
return container_of(inode, struct dax_device, inode);
}
static void dax_i_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
struct dax_device *dax_dev = to_dax_dev(inode);
ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev));
kmem_cache_free(dax_cache, dax_dev);
}
static void dax_destroy_inode(struct inode *inode)
{
struct dax_device *dax_dev = to_dax_dev(inode);
WARN_ONCE(dax_dev->alive,
"kill_dax() must be called before final iput()\n");
call_rcu(&inode->i_rcu, dax_i_callback);
}
static const struct super_operations dax_sops = {
.statfs = simple_statfs,
.alloc_inode = dax_alloc_inode,
.destroy_inode = dax_destroy_inode,
.drop_inode = generic_delete_inode,
};
static struct dentry *dax_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC);
}
static struct file_system_type dax_fs_type = {
.name = "dax",
.mount = dax_mount,
.kill_sb = kill_anon_super,
};
static int dax_test(struct inode *inode, void *data)
{
dev_t devt = *(dev_t *) data;
return inode->i_rdev == devt;
}
static int dax_set(struct inode *inode, void *data)
{
dev_t devt = *(dev_t *) data;
inode->i_rdev = devt;
return 0;
}
static struct dax_device *dax_dev_get(dev_t devt)
{
struct dax_device *dax_dev;
struct inode *inode;
inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31),
dax_test, dax_set, &devt);
if (!inode)
return NULL;
dax_dev = to_dax_dev(inode);
if (inode->i_state & I_NEW) {
dax_dev->alive = true;
inode->i_cdev = &dax_dev->cdev;
inode->i_mode = S_IFCHR;
inode->i_flags = S_DAX;
mapping_set_gfp_mask(&inode->i_data, GFP_USER);
unlock_new_inode(inode);
}
return dax_dev;
}
struct dax_device *alloc_dax(void *private)
{
struct dax_device *dax_dev;
dev_t devt;
int minor;
minor = ida_simple_get(&dax_minor_ida, 0, nr_dax, GFP_KERNEL);
if (minor < 0)
return NULL;
devt = MKDEV(MAJOR(dax_devt), minor);
dax_dev = dax_dev_get(devt);
if (!dax_dev)
goto err_inode;
dax_dev->private = private;
return dax_dev;
err_inode:
ida_simple_remove(&dax_minor_ida, minor);
return NULL;
}
EXPORT_SYMBOL_GPL(alloc_dax);
void put_dax(struct dax_device *dax_dev)
{
if (!dax_dev)
return;
iput(&dax_dev->inode);
}
EXPORT_SYMBOL_GPL(put_dax);
/**
* inode_dax: convert a public inode into its dax_dev
* @inode: An inode with i_cdev pointing to a dax_dev
*
* Note this is not equivalent to to_dax_dev() which is for private
* internal use where we know the inode filesystem type == dax_fs_type.
*/
struct dax_device *inode_dax(struct inode *inode)
{
struct cdev *cdev = inode->i_cdev;
return container_of(cdev, struct dax_device, cdev);
}
EXPORT_SYMBOL_GPL(inode_dax);
struct inode *dax_inode(struct dax_device *dax_dev)
{
return &dax_dev->inode;
}
EXPORT_SYMBOL_GPL(dax_inode);
void *dax_get_private(struct dax_device *dax_dev)
{
return dax_dev->private;
}
EXPORT_SYMBOL_GPL(dax_get_private);
static void init_once(void *_dax_dev)
{
struct dax_device *dax_dev = _dax_dev;
struct inode *inode = &dax_dev->inode;
inode_init_once(inode);
}
static int __dax_fs_init(void)
{
int rc;
dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0,
(SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD|SLAB_ACCOUNT),
init_once);
if (!dax_cache)
return -ENOMEM;
rc = register_filesystem(&dax_fs_type);
if (rc)
goto err_register_fs;
dax_mnt = kern_mount(&dax_fs_type);
if (IS_ERR(dax_mnt)) {
rc = PTR_ERR(dax_mnt);
goto err_mount;
}
dax_superblock = dax_mnt->mnt_sb;
return 0;
err_mount:
unregister_filesystem(&dax_fs_type);
err_register_fs:
kmem_cache_destroy(dax_cache);
return rc;
}
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)
{
int rc;
rc = __dax_fs_init();
if (rc)
return rc;
nr_dax = max(nr_dax, 256);
rc = alloc_chrdev_region(&dax_devt, 0, nr_dax, "dax");
if (rc)
__dax_fs_exit();
return rc;
}
static void __exit dax_fs_exit(void)
{
unregister_chrdev_region(dax_devt, nr_dax);
ida_destroy(&dax_minor_ida);
__dax_fs_exit();
}
MODULE_AUTHOR("Intel Corporation");
MODULE_LICENSE("GPL v2");
subsys_initcall(dax_fs_init);
module_exit(dax_fs_exit);

3
include/linux/dax.h
View File

@ -8,6 +8,9 @@
struct iomap_ops;
int dax_read_lock(void);
void dax_read_unlock(int id);
/*
* We use lowest available bit in exceptional entry for locking, one bit for
* the entry size (PMD) and two more to tell us if the entry is a huge zero

10
tools/testing/nvdimm/Kbuild
View File

@ -28,7 +28,10 @@ obj-$(CONFIG_ND_BTT) += nd_btt.o
obj-$(CONFIG_ND_BLK) += nd_blk.o
obj-$(CONFIG_X86_PMEM_LEGACY) += nd_e820.o
obj-$(CONFIG_ACPI_NFIT) += nfit.o
obj-$(CONFIG_DEV_DAX) += dax.o
ifeq ($(CONFIG_DAX),m)
obj-$(CONFIG_DAX) += dax.o
endif
obj-$(CONFIG_DEV_DAX) += device_dax.o
obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
nfit-y := $(ACPI_SRC)/core.o
@ -48,9 +51,12 @@ nd_blk-y += config_check.o
nd_e820-y := $(NVDIMM_SRC)/e820.o
nd_e820-y += config_check.o
dax-y := $(DAX_SRC)/dax.o
dax-y := $(DAX_SRC)/super.o
dax-y += config_check.o
device_dax-y := $(DAX_SRC)/device.o
device_dax-y += config_check.o
dax_pmem-y := $(DAX_SRC)/pmem.o
dax_pmem-y += config_check.o