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