linux/drivers/dax/device.c
Matthew Wilcox (Oracle) 1d024e7a8d mm: remove enum page_entry_size
Remove the unnecessary encoding of page order into an enum and pass the
page order directly.  That lets us get rid of pe_order().

The switch constructs have to be changed to if/else constructs to prevent
GCC from warning on builds with 3-level page tables where PMD_ORDER and
PUD_ORDER have the same value.

If you are looking at this commit because your driver stopped compiling,
look at the previous commit as well and audit your driver to be sure it
doesn't depend on mmap_lock being held in its ->huge_fault method.

[willy@infradead.org: use "order %u" to match the (non dev_t) style]
  Link: https://lkml.kernel.org/r/ZOUYekbtTv+n8hYf@casper.infradead.org
Link: https://lkml.kernel.org/r/20230818202335.2739663-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-24 16:20:30 -07:00

489 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2016-2018 Intel Corporation. All rights reserved. */
#include <linux/memremap.h>
#include <linux/pagemap.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/pfn_t.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include <linux/dax.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include "dax-private.h"
#include "bus.h"
static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
const char *func)
{
struct device *dev = &dev_dax->dev;
unsigned long mask;
if (!dax_alive(dev_dax->dax_dev))
return -ENXIO;
/* prevent private mappings from being established */
if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
dev_info_ratelimited(dev,
"%s: %s: fail, attempted private mapping\n",
current->comm, func);
return -EINVAL;
}
mask = dev_dax->align - 1;
if (vma->vm_start & mask || vma->vm_end & mask) {
dev_info_ratelimited(dev,
"%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
current->comm, func, vma->vm_start, vma->vm_end,
mask);
return -EINVAL;
}
if (!vma_is_dax(vma)) {
dev_info_ratelimited(dev,
"%s: %s: fail, vma is not DAX capable\n",
current->comm, func);
return -EINVAL;
}
return 0;
}
/* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
__weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
unsigned long size)
{
int i;
for (i = 0; i < dev_dax->nr_range; i++) {
struct dev_dax_range *dax_range = &dev_dax->ranges[i];
struct range *range = &dax_range->range;
unsigned long long pgoff_end;
phys_addr_t phys;
pgoff_end = dax_range->pgoff + PHYS_PFN(range_len(range)) - 1;
if (pgoff < dax_range->pgoff || pgoff > pgoff_end)
continue;
phys = PFN_PHYS(pgoff - dax_range->pgoff) + range->start;
if (phys + size - 1 <= range->end)
return phys;
break;
}
return -1;
}
static void dax_set_mapping(struct vm_fault *vmf, pfn_t pfn,
unsigned long fault_size)
{
unsigned long i, nr_pages = fault_size / PAGE_SIZE;
struct file *filp = vmf->vma->vm_file;
struct dev_dax *dev_dax = filp->private_data;
pgoff_t pgoff;
/* mapping is only set on the head */
if (dev_dax->pgmap->vmemmap_shift)
nr_pages = 1;
pgoff = linear_page_index(vmf->vma,
ALIGN(vmf->address, fault_size));
for (i = 0; i < nr_pages; i++) {
struct page *page = pfn_to_page(pfn_t_to_pfn(pfn) + i);
page = compound_head(page);
if (page->mapping)
continue;
page->mapping = filp->f_mapping;
page->index = pgoff + i;
}
}
static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
struct vm_fault *vmf)
{
struct device *dev = &dev_dax->dev;
phys_addr_t phys;
pfn_t pfn;
unsigned int fault_size = PAGE_SIZE;
if (check_vma(dev_dax, vmf->vma, __func__))
return VM_FAULT_SIGBUS;
if (dev_dax->align > PAGE_SIZE) {
dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
dev_dax->align, fault_size);
return VM_FAULT_SIGBUS;
}
if (fault_size != dev_dax->align)
return VM_FAULT_SIGBUS;
phys = dax_pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE);
if (phys == -1) {
dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", vmf->pgoff);
return VM_FAULT_SIGBUS;
}
pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
dax_set_mapping(vmf, pfn, fault_size);
return vmf_insert_mixed(vmf->vma, vmf->address, pfn);
}
static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
struct vm_fault *vmf)
{
unsigned long pmd_addr = vmf->address & PMD_MASK;
struct device *dev = &dev_dax->dev;
phys_addr_t phys;
pgoff_t pgoff;
pfn_t pfn;
unsigned int fault_size = PMD_SIZE;
if (check_vma(dev_dax, vmf->vma, __func__))
return VM_FAULT_SIGBUS;
if (dev_dax->align > PMD_SIZE) {
dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
dev_dax->align, fault_size);
return VM_FAULT_SIGBUS;
}
if (fault_size < dev_dax->align)
return VM_FAULT_SIGBUS;
else if (fault_size > dev_dax->align)
return VM_FAULT_FALLBACK;
/* if we are outside of the VMA */
if (pmd_addr < vmf->vma->vm_start ||
(pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
return VM_FAULT_SIGBUS;
pgoff = linear_page_index(vmf->vma, pmd_addr);
phys = dax_pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
if (phys == -1) {
dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
return VM_FAULT_SIGBUS;
}
pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
dax_set_mapping(vmf, pfn, fault_size);
return vmf_insert_pfn_pmd(vmf, pfn, vmf->flags & FAULT_FLAG_WRITE);
}
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
struct vm_fault *vmf)
{
unsigned long pud_addr = vmf->address & PUD_MASK;
struct device *dev = &dev_dax->dev;
phys_addr_t phys;
pgoff_t pgoff;
pfn_t pfn;
unsigned int fault_size = PUD_SIZE;
if (check_vma(dev_dax, vmf->vma, __func__))
return VM_FAULT_SIGBUS;
if (dev_dax->align > PUD_SIZE) {
dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
dev_dax->align, fault_size);
return VM_FAULT_SIGBUS;
}
if (fault_size < dev_dax->align)
return VM_FAULT_SIGBUS;
else if (fault_size > dev_dax->align)
return VM_FAULT_FALLBACK;
/* if we are outside of the VMA */
if (pud_addr < vmf->vma->vm_start ||
(pud_addr + PUD_SIZE) > vmf->vma->vm_end)
return VM_FAULT_SIGBUS;
pgoff = linear_page_index(vmf->vma, pud_addr);
phys = dax_pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
if (phys == -1) {
dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
return VM_FAULT_SIGBUS;
}
pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
dax_set_mapping(vmf, pfn, fault_size);
return vmf_insert_pfn_pud(vmf, pfn, vmf->flags & FAULT_FLAG_WRITE);
}
#else
static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
struct vm_fault *vmf)
{
return VM_FAULT_FALLBACK;
}
#endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, unsigned int order)
{
struct file *filp = vmf->vma->vm_file;
vm_fault_t rc = VM_FAULT_SIGBUS;
int id;
struct dev_dax *dev_dax = filp->private_data;
dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) order:%d\n", current->comm,
(vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
vmf->vma->vm_start, vmf->vma->vm_end, order);
id = dax_read_lock();
if (order == 0)
rc = __dev_dax_pte_fault(dev_dax, vmf);
else if (order == PMD_ORDER)
rc = __dev_dax_pmd_fault(dev_dax, vmf);
else if (order == PUD_ORDER)
rc = __dev_dax_pud_fault(dev_dax, vmf);
else
rc = VM_FAULT_SIGBUS;
dax_read_unlock(id);
return rc;
}
static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
{
return dev_dax_huge_fault(vmf, 0);
}
static int dev_dax_may_split(struct vm_area_struct *vma, unsigned long addr)
{
struct file *filp = vma->vm_file;
struct dev_dax *dev_dax = filp->private_data;
if (!IS_ALIGNED(addr, dev_dax->align))
return -EINVAL;
return 0;
}
static unsigned long dev_dax_pagesize(struct vm_area_struct *vma)
{
struct file *filp = vma->vm_file;
struct dev_dax *dev_dax = filp->private_data;
return dev_dax->align;
}
static const struct vm_operations_struct dax_vm_ops = {
.fault = dev_dax_fault,
.huge_fault = dev_dax_huge_fault,
.may_split = dev_dax_may_split,
.pagesize = dev_dax_pagesize,
};
static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct dev_dax *dev_dax = filp->private_data;
int rc, id;
dev_dbg(&dev_dax->dev, "trace\n");
/*
* 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;
vma->vm_ops = &dax_vm_ops;
vm_flags_set(vma, VM_HUGEPAGE);
return 0;
}
/* return an unmapped area aligned to the dax region specified alignment */
static unsigned long dax_get_unmapped_area(struct file *filp,
unsigned long addr, unsigned long len, unsigned long pgoff,
unsigned long flags)
{
unsigned long off, off_end, off_align, len_align, addr_align, align;
struct dev_dax *dev_dax = filp ? filp->private_data : NULL;
if (!dev_dax || addr)
goto out;
align = dev_dax->align;
off = pgoff << PAGE_SHIFT;
off_end = off + len;
off_align = round_up(off, align);
if ((off_end <= off_align) || ((off_end - off_align) < align))
goto out;
len_align = len + align;
if ((off + len_align) < off)
goto out;
addr_align = current->mm->get_unmapped_area(filp, addr, len_align,
pgoff, flags);
if (!IS_ERR_VALUE(addr_align)) {
addr_align += (off - addr_align) & (align - 1);
return addr_align;
}
out:
return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
}
static const struct address_space_operations dev_dax_aops = {
.dirty_folio = noop_dirty_folio,
};
static int dax_open(struct inode *inode, struct file *filp)
{
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_dbg(&dev_dax->dev, "trace\n");
inode->i_mapping = __dax_inode->i_mapping;
inode->i_mapping->host = __dax_inode;
inode->i_mapping->a_ops = &dev_dax_aops;
filp->f_mapping = inode->i_mapping;
filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
filp->f_sb_err = file_sample_sb_err(filp);
filp->private_data = dev_dax;
inode->i_flags = S_DAX;
return 0;
}
static int dax_release(struct inode *inode, struct file *filp)
{
struct dev_dax *dev_dax = filp->private_data;
dev_dbg(&dev_dax->dev, "trace\n");
return 0;
}
static const struct file_operations dax_fops = {
.llseek = noop_llseek,
.owner = THIS_MODULE,
.open = dax_open,
.release = dax_release,
.get_unmapped_area = dax_get_unmapped_area,
.mmap = dax_mmap,
.mmap_supported_flags = MAP_SYNC,
};
static void dev_dax_cdev_del(void *cdev)
{
cdev_del(cdev);
}
static void dev_dax_kill(void *dev_dax)
{
kill_dev_dax(dev_dax);
}
static int dev_dax_probe(struct dev_dax *dev_dax)
{
struct dax_device *dax_dev = dev_dax->dax_dev;
struct device *dev = &dev_dax->dev;
struct dev_pagemap *pgmap;
struct inode *inode;
struct cdev *cdev;
void *addr;
int rc, i;
if (static_dev_dax(dev_dax)) {
if (dev_dax->nr_range > 1) {
dev_warn(dev,
"static pgmap / multi-range device conflict\n");
return -EINVAL;
}
pgmap = dev_dax->pgmap;
} else {
if (dev_dax->pgmap) {
dev_warn(dev,
"dynamic-dax with pre-populated page map\n");
return -EINVAL;
}
pgmap = devm_kzalloc(dev,
struct_size(pgmap, ranges, dev_dax->nr_range - 1),
GFP_KERNEL);
if (!pgmap)
return -ENOMEM;
pgmap->nr_range = dev_dax->nr_range;
dev_dax->pgmap = pgmap;
for (i = 0; i < dev_dax->nr_range; i++) {
struct range *range = &dev_dax->ranges[i].range;
pgmap->ranges[i] = *range;
}
}
for (i = 0; i < dev_dax->nr_range; i++) {
struct range *range = &dev_dax->ranges[i].range;
if (!devm_request_mem_region(dev, range->start,
range_len(range), dev_name(dev))) {
dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve range\n",
i, range->start, range->end);
return -EBUSY;
}
}
pgmap->type = MEMORY_DEVICE_GENERIC;
if (dev_dax->align > PAGE_SIZE)
pgmap->vmemmap_shift =
order_base_2(dev_dax->align >> PAGE_SHIFT);
addr = devm_memremap_pages(dev, pgmap);
if (IS_ERR(addr))
return PTR_ERR(addr);
inode = dax_inode(dax_dev);
cdev = inode->i_cdev;
cdev_init(cdev, &dax_fops);
cdev->owner = dev->driver->owner;
cdev_set_parent(cdev, &dev->kobj);
rc = cdev_add(cdev, dev->devt, 1);
if (rc)
return rc;
rc = devm_add_action_or_reset(dev, dev_dax_cdev_del, cdev);
if (rc)
return rc;
run_dax(dax_dev);
return devm_add_action_or_reset(dev, dev_dax_kill, dev_dax);
}
static struct dax_device_driver device_dax_driver = {
.probe = dev_dax_probe,
.type = DAXDRV_DEVICE_TYPE,
};
static int __init dax_init(void)
{
return dax_driver_register(&device_dax_driver);
}
static void __exit dax_exit(void)
{
dax_driver_unregister(&device_dax_driver);
}
MODULE_AUTHOR("Intel Corporation");
MODULE_LICENSE("GPL v2");
module_init(dax_init);
module_exit(dax_exit);
MODULE_ALIAS_DAX_DEVICE(0);