linux/drivers/dax/dax-private.h
Dan Williams 60ef1f64d3 dax: Introduce alloc_dev_dax_id()
[ Upstream commit 70aab281e1 ]

The reference counting of dax_region objects is needlessly complicated,
has lead to confusion [1], and has hidden a bug [2]. Towards cleaning up
that mess introduce alloc_dev_dax_id() to minimize the holding of a
dax_region reference to only what dev_dax_release() needs, the
dax_region->ida.

Part of the reason for the mess was the design to dereference a
dax_region in all cases in free_dev_dax_id() even if the id was
statically assigned by the upper level dax_region driver. Remove the
need to call "is_static(dax_region)" by tracking whether the id is
dynamic directly in the dev_dax instance itself.

With that flag the dax_region pinning and release per dev_dax instance
can move to alloc_dev_dax_id() and free_dev_dax_id() respectively.

A follow-on cleanup address the unnecessary references in the dax_region
setup and drivers.

Fixes: 0f3da14a4f ("device-dax: introduce 'seed' devices")
Link: http://lore.kernel.org/r/20221203095858.612027-1-liuyongqiang13@huawei.com [1]
Link: http://lore.kernel.org/r/3cf0890b-4eb0-e70e-cd9c-2ecc3d496263@hpe.com [2]
Reported-by: Yongqiang Liu <liuyongqiang13@huawei.com>
Reported-by: Paul Cassella <cassella@hpe.com>
Reported-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/168577284563.1672036.13493034988900989554.stgit@dwillia2-xfh.jf.intel.com
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-19 16:36:20 +02:00

111 lines
2.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright(c) 2016 Intel Corporation. All rights reserved.
*/
#ifndef __DAX_PRIVATE_H__
#define __DAX_PRIVATE_H__
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/idr.h>
/* private routines between core files */
struct dax_device;
struct dax_device *inode_dax(struct inode *inode);
struct inode *dax_inode(struct dax_device *dax_dev);
int dax_bus_init(void);
void dax_bus_exit(void);
/**
* struct dax_region - mapping infrastructure for dax devices
* @id: kernel-wide unique region for a memory range
* @target_node: effective numa node if this memory range is onlined
* @kref: to pin while other agents have a need to do lookups
* @dev: parent device backing this region
* @align: allocation and mapping alignment for child dax devices
* @ida: instance id allocator
* @res: resource tree to track instance allocations
* @seed: allow userspace to find the first unbound seed device
* @youngest: allow userspace to find the most recently created device
*/
struct dax_region {
int id;
int target_node;
struct kref kref;
struct device *dev;
unsigned int align;
struct ida ida;
struct resource res;
struct device *seed;
struct device *youngest;
};
struct dax_mapping {
struct device dev;
int range_id;
int id;
};
/**
* struct dev_dax - instance data for a subdivision of a dax region, and
* data while the device is activated in the driver.
* @region - parent region
* @dax_dev - core dax functionality
* @target_node: effective numa node if dev_dax memory range is onlined
* @dyn_id: is this a dynamic or statically created instance
* @id: ida allocated id when the dax_region is not static
* @ida: mapping id allocator
* @dev - device core
* @pgmap - pgmap for memmap setup / lifetime (driver owned)
* @nr_range: size of @ranges
* @ranges: resource-span + pgoff tuples for the instance
*/
struct dev_dax {
struct dax_region *region;
struct dax_device *dax_dev;
unsigned int align;
int target_node;
bool dyn_id;
int id;
struct ida ida;
struct device dev;
struct dev_pagemap *pgmap;
int nr_range;
struct dev_dax_range {
unsigned long pgoff;
struct range range;
struct dax_mapping *mapping;
} *ranges;
};
static inline struct dev_dax *to_dev_dax(struct device *dev)
{
return container_of(dev, struct dev_dax, dev);
}
static inline struct dax_mapping *to_dax_mapping(struct device *dev)
{
return container_of(dev, struct dax_mapping, dev);
}
phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff, unsigned long size);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline bool dax_align_valid(unsigned long align)
{
if (align == PUD_SIZE && IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
return true;
if (align == PMD_SIZE && has_transparent_hugepage())
return true;
if (align == PAGE_SIZE)
return true;
return false;
}
#else
static inline bool dax_align_valid(unsigned long align)
{
return align == PAGE_SIZE;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif