Commit 977fbdcd authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
Browse files

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: default avatarMatthew Wilcox <mawilcox@microsoft.com>
Reported-by: default avatar"zhangyi (F)" <yi.zhang@huawei.com>
Reviewed-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a365ac09

fs/dax.c

+6 −13
Original line number Diff line number Diff line
@@ -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)

{

include/linux/mm.h

+16 −10
Original line number Diff line number Diff line
@@ -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,

mm/khugepaged.c

+1 −2
Original line number Diff line number Diff line
@@ -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);

mm/memory.c

+31 −12
Original line number Diff line number Diff line
@@ -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);

mm/nommu.c

+0 −7
Original line number Diff line number Diff line
@@ -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();

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