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mm: add unmap_mapping_pages() 

Several users of unmap_mapping_range() would prefer to express their
range in pages rather than bytes.  Unfortuately, on a 32-bit kernel, you
have to remember to cast your page number to a 64-bit type before
shifting it, and four places in the current tree didn't remember to do
that.  That's a sign of a bad interface.

Conveniently, unmap_mapping_range() actually converts from bytes into
pages, so hoist the guts of unmap_mapping_range() into a new function
unmap_mapping_pages() and convert the callers which want to use pages.

Link: http://lkml.kernel.org/r/20171206142627.GD32044@bombadil.infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Reported-by: "zhangyi (F)" <yi.zhang@huawei.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Matthew Wilcox 2018-01-31 16:17:36 -08:00 committed by Linus Torvalds
parent a365ac09d3
commit 977fbdcd59
6 changed files with 61 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
fs/dax.c
View File

@ -44,6 +44,7 @@
/* The 'colour' (ie low bits) within a PMD of a page offset. */
#define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1)
#define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT)
static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES];
@ -375,8 +376,8 @@ restart:
* unmapped.
*/
if (pmd_downgrade && dax_is_zero_entry(entry))
unmap_mapping_range(mapping,
(index << PAGE_SHIFT) & PMD_MASK, PMD_SIZE, 0);
unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR,
PG_PMD_NR, false);
err = radix_tree_preload(
mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM);
@ -538,12 +539,10 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
if (dax_is_zero_entry(entry) && !(flags & RADIX_DAX_ZERO_PAGE)) {
/* we are replacing a zero page with block mapping */
if (dax_is_pmd_entry(entry))
unmap_mapping_range(mapping,
(vmf->pgoff << PAGE_SHIFT) & PMD_MASK,
PMD_SIZE, 0);
unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR,
PG_PMD_NR, false);
else /* pte entry */
unmap_mapping_range(mapping, vmf->pgoff << PAGE_SHIFT,
PAGE_SIZE, 0);
unmap_mapping_pages(mapping, vmf->pgoff, 1, false);
}
spin_lock_irq(&mapping->tree_lock);
@ -1269,12 +1268,6 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
}
#ifdef CONFIG_FS_DAX_PMD
/*
* The 'colour' (ie low bits) within a PMD of a page offset. This comes up
* more often than one might expect in the below functions.
*/
#define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1)
static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
void *entry)
{

26
include/linux/mm.h
View File

@ -1312,8 +1312,6 @@ void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
unsigned long end, unsigned long floor, unsigned long ceiling);
int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
struct vm_area_struct *vma);
void unmap_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen, int even_cows);
int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
unsigned long *start, unsigned long *end,
pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp);
@ -1324,12 +1322,6 @@ int follow_phys(struct vm_area_struct *vma, unsigned long address,
int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
void *buf, int len, int write);
static inline void unmap_shared_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen)
{
unmap_mapping_range(mapping, holebegin, holelen, 0);
}
extern void truncate_pagecache(struct inode *inode, loff_t new);
extern void truncate_setsize(struct inode *inode, loff_t newsize);
void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to);
@ -1344,6 +1336,10 @@ extern int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
extern int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
unsigned long address, unsigned int fault_flags,
bool *unlocked);
void unmap_mapping_pages(struct address_space *mapping,
pgoff_t start, pgoff_t nr, bool even_cows);
void unmap_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen, int even_cows);
#else
static inline int handle_mm_fault(struct vm_area_struct *vma,
unsigned long address, unsigned int flags)
@ -1360,10 +1356,20 @@ static inline int fixup_user_fault(struct task_struct *tsk,
BUG();
return -EFAULT;
}
static inline void unmap_mapping_pages(struct address_space *mapping,
pgoff_t start, pgoff_t nr, bool even_cows) { }
static inline void unmap_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen, int even_cows) { }
#endif
extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len,
unsigned int gup_flags);
static inline void unmap_shared_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen)
{
unmap_mapping_range(mapping, holebegin, holelen, 0);
}
extern int access_process_vm(struct task_struct *tsk, unsigned long addr,
void *buf, int len, unsigned int gup_flags);
extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
void *buf, int len, unsigned int gup_flags);
extern int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,

3
mm/khugepaged.c
View File

@ -1399,8 +1399,7 @@ static void collapse_shmem(struct mm_struct *mm,
}
if (page_mapped(page))
unmap_mapping_range(mapping, index << PAGE_SHIFT,
PAGE_SIZE, 0);
unmap_mapping_pages(mapping, index, 1, false);
spin_lock_irq(&mapping->tree_lock);

43
mm/memory.c
View File

@ -2798,9 +2798,38 @@ static inline void unmap_mapping_range_tree(struct rb_root_cached *root,
}
}
/**
* unmap_mapping_pages() - Unmap pages from processes.
* @mapping: The address space containing pages to be unmapped.
* @start: Index of first page to be unmapped.
* @nr: Number of pages to be unmapped. 0 to unmap to end of file.
* @even_cows: Whether to unmap even private COWed pages.
*
* Unmap the pages in this address space from any userspace process which
* has them mmaped. Generally, you want to remove COWed pages as well when
* a file is being truncated, but not when invalidating pages from the page
* cache.
*/
void unmap_mapping_pages(struct address_space *mapping, pgoff_t start,
pgoff_t nr, bool even_cows)
{
struct zap_details details = { };
details.check_mapping = even_cows ? NULL : mapping;
details.first_index = start;
details.last_index = start + nr - 1;
if (details.last_index < details.first_index)
details.last_index = ULONG_MAX;
i_mmap_lock_write(mapping);
if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)))
unmap_mapping_range_tree(&mapping->i_mmap, &details);
i_mmap_unlock_write(mapping);
}
/**
* unmap_mapping_range - unmap the portion of all mmaps in the specified
* address_space corresponding to the specified page range in the underlying
* address_space corresponding to the specified byte range in the underlying
* file.
*
* @mapping: the address space containing mmaps to be unmapped.
@ -2818,7 +2847,6 @@ static inline void unmap_mapping_range_tree(struct rb_root_cached *root,
void unmap_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen, int even_cows)
{
struct zap_details details = { };
pgoff_t hba = holebegin >> PAGE_SHIFT;
pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
@ -2830,16 +2858,7 @@ void unmap_mapping_range(struct address_space *mapping,
hlen = ULONG_MAX - hba + 1;
}
details.check_mapping = even_cows ? NULL : mapping;
details.first_index = hba;
details.last_index = hba + hlen - 1;
if (details.last_index < details.first_index)
details.last_index = ULONG_MAX;
i_mmap_lock_write(mapping);
if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)))
unmap_mapping_range_tree(&mapping->i_mmap, &details);
i_mmap_unlock_write(mapping);
unmap_mapping_pages(mapping, hba, hlen, even_cows);
}
EXPORT_SYMBOL(unmap_mapping_range);

7
mm/nommu.c
View File

@ -1788,13 +1788,6 @@ unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
return -ENOMEM;
}
void unmap_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen,
int even_cows)
{
}
EXPORT_SYMBOL(unmap_mapping_range);
int filemap_fault(struct vm_fault *vmf)
{
BUG();

23
mm/truncate.c
View File

@ -179,12 +179,8 @@ static void
truncate_cleanup_page(struct address_space *mapping, struct page *page)
{
if (page_mapped(page)) {
loff_t holelen;
holelen = PageTransHuge(page) ? HPAGE_PMD_SIZE : PAGE_SIZE;
unmap_mapping_range(mapping,
(loff_t)page->index << PAGE_SHIFT,
holelen, 0);
pgoff_t nr = PageTransHuge(page) ? HPAGE_PMD_NR : 1;
unmap_mapping_pages(mapping, page->index, nr, false);
}
if (page_has_private(page))
@ -715,19 +711,15 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
/*
* Zap the rest of the file in one hit.
*/
unmap_mapping_range(mapping,
(loff_t)index << PAGE_SHIFT,
(loff_t)(1 + end - index)
<< PAGE_SHIFT,
0);
unmap_mapping_pages(mapping, index,
(1 + end - index), false);
did_range_unmap = 1;
} else {
/*
* Just zap this page
*/
unmap_mapping_range(mapping,
(loff_t)index << PAGE_SHIFT,
PAGE_SIZE, 0);
unmap_mapping_pages(mapping, index,
1, false);
}
}
BUG_ON(page_mapped(page));
@ -753,8 +745,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
* get remapped later.
*/
if (dax_mapping(mapping)) {
unmap_mapping_range(mapping, (loff_t)start << PAGE_SHIFT,
(loff_t)(end - start + 1) << PAGE_SHIFT, 0);
unmap_mapping_pages(mapping, start, end - start + 1, false);
}
out:
cleancache_invalidate_inode(mapping);