Files
John Groves ff7c73fca7 dax/fsdev: use __va(phys) for kaddr in direct_access
Use __va(phys) instead of virt_addr + linear_offset for the kaddr
return in __fsdev_dax_direct_access(). The previous code added a
device-linear byte offset to virt_addr (which is __va of ranges[0]),
but for multi-range devices with physical gaps between ranges, this
linear arithmetic crosses the gap and produces a wrong kernel virtual
address. Using __va(phys) where phys comes from dax_pgoff_to_phys()
is correct for any range layout because the direct map translates
each physical address independently.

This leaves dev_dax->virt_addr write-only, so remove the field
(suggested by Dave Jiang).

Fixes: 759455848d ("dax: Save the kva from memremap")

Reviewed-by: Dave Jiang <[email protected]>
Reviewed-by: Alison Schofield <[email protected]>
Signed-off-by: John Groves <[email protected]>
Link: https://patch.msgid.link/0100019ecc096de8-8bc254a7-d2cc-44b6-82b1-1394fda8bb41-000000@email.amazonses.com
Signed-off-by: Alison Schofield <[email protected]>
2026-07-14 16:26:43 -07:00

137 lines
3.7 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 - device to display mapping range attributes
* @dev: device representing this range
* @range_id: index within dev_dax ranges array
* @id: ida of this mapping
*/
struct dax_mapping {
struct device dev;
int range_id;
int id;
};
/**
* struct dev_dax_range - tuple represenging a range of memory used by dev_dax
* @pgoff: page offset
* @range: resource-span
* @mapping: reference to the dax_mapping for this range
*/
struct dev_dax_range {
unsigned long pgoff;
struct range range;
struct dax_mapping *mapping;
};
/**
* 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
* @cached_size: size of daxdev cached by fsdev_dax
* @align: alignment of this instance
* @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)
* @memmap_on_memory: allow kmem to put the memmap in the memory
* @nr_range: size of @ranges
* @ranges: range tuples of memory used
*/
struct dev_dax {
struct dax_region *region;
struct dax_device *dax_dev;
u64 cached_size;
unsigned int align;
int target_node;
bool dyn_id;
int id;
struct ida ida;
struct device dev;
struct dev_pagemap *pgmap;
bool memmap_on_memory;
int nr_range;
struct dev_dax_range *ranges;
};
/*
* 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
* outside of drivers/dax/
*/
void run_dax(struct dax_device *dax_dev);
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