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dax: Kill DEV_DAX_PMEM_COMPAT

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The /sys/class/dax compatibility option has shipped in the kernel for 4
years now which should be sufficient time for tools to abandon the old
ABI in favor of the /sys/bus/dax device-model. Delete it now and see if
anyone screams.

Since this compatibility option shipped there has been more reports of
users being surprised by the compat ABI than surprised by the "new", so
the compat infrastructure has outlived its usefulness. Recall that
/sys/bus/dax device-model is required for the dax kmem driver which
allows PMEM to be used as "System RAM".

The following projects were known to have a dependency on /sys/class/dax
and have dropped their dependency as of the listed version:

- ndctl (including libndctl, daxctl, and libdaxctl): v64+
- fio: v3.13+
- pmdk: v1.5.2+

As further evidence this option is no longer needed some distributions
have already stopped enabling CONFIG_DEV_DAX_PMEM_COMPAT.

Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Reported-by: Vishal Verma <vishal.l.verma@intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Link: https://lore.kernel.org/r/163701116195.3784476.726128179293466337.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2021-11-15 13:20:57 -08:00
parent fa55b7dcdc
commit 83762cb5c7
15 changed files with 36 additions and 209 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
Documentation/ABI/obsolete/sysfs-class-dax
View File

@ -1,22 +0,0 @@
What: /sys/class/dax/
Date: May, 2016
KernelVersion: v4.7
Contact: nvdimm@lists.linux.dev
Description: Device DAX is the device-centric analogue of Filesystem
DAX (CONFIG_FS_DAX). It allows memory ranges to be
allocated and mapped without need of an intervening file
system. Device DAX is strict, precise and predictable.
Specifically this interface:
1. Guarantees fault granularity with respect to a given
page size (pte, pmd, or pud) set at configuration time.
2. Enforces deterministic behavior by being strict about
what fault scenarios are supported.
The /sys/class/dax/ interface enumerates all the
device-dax instances in the system. The ABI is
deprecated and will be removed after 2020. It is
replaced with the DAX bus interface /sys/bus/dax/ where
device-dax instances can be found under
/sys/bus/dax/devices/

9
drivers/dax/Kconfig
View File

@ -70,13 +70,4 @@ config DEV_DAX_KMEM
Say N if unsure.
config DEV_DAX_PMEM_COMPAT
tristate "PMEM DAX: support the deprecated /sys/class/dax interface"
depends on m && DEV_DAX_PMEM=m
default DEV_DAX_PMEM
help
Older versions of the libdaxctl library expect to find all
device-dax instances under /sys/class/dax. If libdaxctl in
your distribution is older than v58 say M, otherwise say N.
endif

3
drivers/dax/Makefile
View File

@ -2,10 +2,11 @@
obj-$(CONFIG_DAX) += dax.o
obj-$(CONFIG_DEV_DAX) += device_dax.o
obj-$(CONFIG_DEV_DAX_KMEM) += kmem.o
obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
dax-y := super.o
dax-y += bus.o
device_dax-y := device.o
dax_pmem-y := pmem.o
obj-y += pmem/
obj-y += hmem/

21
drivers/dax/bus.c
View File

@ -10,8 +10,6 @@
#include "dax-private.h"
#include "bus.h"
static struct class *dax_class;
static DEFINE_MUTEX(dax_bus_lock);
#define DAX_NAME_LEN 30
@ -1343,10 +1341,7 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
inode = dax_inode(dax_dev);
dev->devt = inode->i_rdev;
if (data->subsys == DEV_DAX_BUS)
dev->bus = &dax_bus_type;
else
dev->class = dax_class;
dev->bus = &dax_bus_type;
dev->parent = parent;
dev->type = &dev_dax_type;
@ -1445,22 +1440,10 @@ EXPORT_SYMBOL_GPL(dax_driver_unregister);
int __init dax_bus_init(void)
{
int rc;
if (IS_ENABLED(CONFIG_DEV_DAX_PMEM_COMPAT)) {
dax_class = class_create(THIS_MODULE, "dax");
if (IS_ERR(dax_class))
return PTR_ERR(dax_class);
}
rc = bus_register(&dax_bus_type);
if (rc)
class_destroy(dax_class);
return rc;
return bus_register(&dax_bus_type);
}
void __exit dax_bus_exit(void)
{
bus_unregister(&dax_bus_type);
class_destroy(dax_class);
}

13
drivers/dax/bus.h
View File

@ -16,24 +16,15 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id,
struct range *range, int target_node, unsigned int align,
unsigned long flags);
enum dev_dax_subsys {
DEV_DAX_BUS = 0, /* zeroed dev_dax_data picks this by default */
DEV_DAX_CLASS,
};
struct dev_dax_data {
struct dax_region *dax_region;
struct dev_pagemap *pgmap;
enum dev_dax_subsys subsys;
resource_size_t size;
int id;
};
struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data);
/* to be deleted when DEV_DAX_CLASS is removed */
struct dev_dax *__dax_pmem_probe(struct device *dev, enum dev_dax_subsys subsys);
struct dax_device_driver {
struct device_driver drv;
struct list_head ids;
@ -49,10 +40,6 @@ int __dax_driver_register(struct dax_device_driver *dax_drv,
void dax_driver_unregister(struct dax_device_driver *dax_drv);
void kill_dev_dax(struct dev_dax *dev_dax);
#if IS_ENABLED(CONFIG_DEV_DAX_PMEM_COMPAT)
int dev_dax_probe(struct dev_dax *dev_dax);
#endif
/*
* While run_dax() is potentially a generic operation that could be
* defined in include/linux/dax.h we don't want to grow any users

6
drivers/dax/device.c
View File

@ -433,11 +433,7 @@ int dev_dax_probe(struct dev_dax *dev_dax)
inode = dax_inode(dax_dev);
cdev = inode->i_cdev;
cdev_init(cdev, &dax_fops);
if (dev->class) {
/* for the CONFIG_DEV_DAX_PMEM_COMPAT case */
cdev->owner = dev->parent->driver->owner;
} else
cdev->owner = dev->driver->owner;
cdev->owner = dev->driver->owner;
cdev_set_parent(cdev, &dev->kobj);
rc = cdev_add(cdev, dev->devt, 1);
if (rc)

36
drivers/dax/pmem/core.c → drivers/dax/pmem.c
View File

@ -3,11 +3,11 @@
#include <linux/memremap.h>
#include <linux/module.h>
#include <linux/pfn_t.h>
#include "../../nvdimm/pfn.h"
#include "../../nvdimm/nd.h"
#include "../bus.h"
#include "../nvdimm/pfn.h"
#include "../nvdimm/nd.h"
#include "bus.h"
struct dev_dax *__dax_pmem_probe(struct device *dev, enum dev_dax_subsys subsys)
static struct dev_dax *__dax_pmem_probe(struct device *dev)
{
struct range range;
int rc, id, region_id;
@ -63,7 +63,6 @@ struct dev_dax *__dax_pmem_probe(struct device *dev, enum dev_dax_subsys subsys)
.dax_region = dax_region,
.id = id,
.pgmap = &pgmap,
.subsys = subsys,
.size = range_len(&range),
};
dev_dax = devm_create_dev_dax(&data);
@ -73,7 +72,32 @@ struct dev_dax *__dax_pmem_probe(struct device *dev, enum dev_dax_subsys subsys)
return dev_dax;
}
EXPORT_SYMBOL_GPL(__dax_pmem_probe);
static int dax_pmem_probe(struct device *dev)
{
return PTR_ERR_OR_ZERO(__dax_pmem_probe(dev));
}
static struct nd_device_driver dax_pmem_driver = {
.probe = dax_pmem_probe,
.drv = {
.name = "dax_pmem",
},
.type = ND_DRIVER_DAX_PMEM,
};
static int __init dax_pmem_init(void)
{
return nd_driver_register(&dax_pmem_driver);
}
module_init(dax_pmem_init);
static void __exit dax_pmem_exit(void)
{
driver_unregister(&dax_pmem_driver.drv);
}
module_exit(dax_pmem_exit);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Intel Corporation");
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);

1
drivers/dax/pmem/Makefile
View File

@ -1,7 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem_core.o
obj-$(CONFIG_DEV_DAX_PMEM_COMPAT) += dax_pmem_compat.o
dax_pmem-y := pmem.o
dax_pmem_core-y := core.o

72
drivers/dax/pmem/compat.c
View File

@ -1,72 +0,0 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2016 - 2018 Intel Corporation. All rights reserved. */
#include <linux/percpu-refcount.h>
#include <linux/memremap.h>
#include <linux/module.h>
#include <linux/pfn_t.h>
#include <linux/nd.h>
#include "../bus.h"
/* we need the private definitions to implement compat suport */
#include "../dax-private.h"
static int dax_pmem_compat_probe(struct device *dev)
{
struct dev_dax *dev_dax = __dax_pmem_probe(dev, DEV_DAX_CLASS);
int rc;
if (IS_ERR(dev_dax))
return PTR_ERR(dev_dax);
if (!devres_open_group(&dev_dax->dev, dev_dax, GFP_KERNEL))
return -ENOMEM;
device_lock(&dev_dax->dev);
rc = dev_dax_probe(dev_dax);
device_unlock(&dev_dax->dev);
devres_close_group(&dev_dax->dev, dev_dax);
if (rc)
devres_release_group(&dev_dax->dev, dev_dax);
return rc;
}
static int dax_pmem_compat_release(struct device *dev, void *data)
{
device_lock(dev);
devres_release_group(dev, to_dev_dax(dev));
device_unlock(dev);
return 0;
}
static void dax_pmem_compat_remove(struct device *dev)
{
device_for_each_child(dev, NULL, dax_pmem_compat_release);
}
static struct nd_device_driver dax_pmem_compat_driver = {
.probe = dax_pmem_compat_probe,
.remove = dax_pmem_compat_remove,
.drv = {
.name = "dax_pmem_compat",
},
.type = ND_DRIVER_DAX_PMEM,
};
static int __init dax_pmem_compat_init(void)
{
return nd_driver_register(&dax_pmem_compat_driver);
}
module_init(dax_pmem_compat_init);
static void __exit dax_pmem_compat_exit(void)
{
driver_unregister(&dax_pmem_compat_driver.drv);
}
module_exit(dax_pmem_compat_exit);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Intel Corporation");
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);

30
drivers/dax/pmem/pmem.c
View File

@ -7,34 +7,4 @@
#include <linux/nd.h>
#include "../bus.h"
static int dax_pmem_probe(struct device *dev)
{
return PTR_ERR_OR_ZERO(__dax_pmem_probe(dev, DEV_DAX_BUS));
}
static struct nd_device_driver dax_pmem_driver = {
.probe = dax_pmem_probe,
.drv = {
.name = "dax_pmem",
},
.type = ND_DRIVER_DAX_PMEM,
};
static int __init dax_pmem_init(void)
{
return nd_driver_register(&dax_pmem_driver);
}
module_init(dax_pmem_init);
static void __exit dax_pmem_exit(void)
{
driver_unregister(&dax_pmem_driver.drv);
}
module_exit(dax_pmem_exit);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Intel Corporation");
#if !IS_ENABLED(CONFIG_DEV_DAX_PMEM_COMPAT)
/* For compat builds, don't load this module by default */
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);
#endif

8
tools/testing/nvdimm/Kbuild
View File

@ -35,8 +35,6 @@ obj-$(CONFIG_DAX) += dax.o
endif
obj-$(CONFIG_DEV_DAX) += device_dax.o
obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem_core.o
obj-$(CONFIG_DEV_DAX_PMEM_COMPAT) += dax_pmem_compat.o
nfit-y := $(ACPI_SRC)/core.o
nfit-y += $(ACPI_SRC)/intel.o
@ -67,12 +65,8 @@ device_dax-y += dax-dev.o
device_dax-y += device_dax_test.o
device_dax-y += config_check.o
dax_pmem-y := $(DAX_SRC)/pmem/pmem.o
dax_pmem-y := $(DAX_SRC)/pmem.o
dax_pmem-y += dax_pmem_test.o
dax_pmem_core-y := $(DAX_SRC)/pmem/core.o
dax_pmem_core-y += dax_pmem_core_test.o
dax_pmem_compat-y := $(DAX_SRC)/pmem/compat.o
dax_pmem_compat-y += dax_pmem_compat_test.o
dax_pmem-y += config_check.o
libnvdimm-y := $(NVDIMM_SRC)/core.o

8
tools/testing/nvdimm/dax_pmem_compat_test.c
View File

@ -1,8 +0,0 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright(c) 2019 Intel Corporation. All rights reserved.
#include <linux/module.h>
#include <linux/printk.h>
#include "watermark.h"
nfit_test_watermark(dax_pmem_compat);

8
tools/testing/nvdimm/dax_pmem_core_test.c
View File

@ -1,8 +0,0 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright(c) 2019 Intel Corporation. All rights reserved.
#include <linux/module.h>
#include <linux/printk.h>
#include "watermark.h"
nfit_test_watermark(dax_pmem_core);

4
tools/testing/nvdimm/test/ndtest.c
View File

@ -1054,10 +1054,6 @@ static __init int ndtest_init(void)
libnvdimm_test();
device_dax_test();
dax_pmem_test();
dax_pmem_core_test();
#ifdef CONFIG_DEV_DAX_PMEM_COMPAT
dax_pmem_compat_test();
#endif
nfit_test_setup(ndtest_resource_lookup, NULL);

4
tools/testing/nvdimm/test/nfit.c
View File

@ -3300,10 +3300,6 @@ static __init int nfit_test_init(void)
acpi_nfit_test();
device_dax_test();
dax_pmem_test();
dax_pmem_core_test();
#ifdef CONFIG_DEV_DAX_PMEM_COMPAT
dax_pmem_compat_test();
#endif
nfit_test_setup(nfit_test_lookup, nfit_test_evaluate_dsm);