From 977fbdcd5986c9ff700bf276644d2b1973a53348 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Wed, 31 Jan 2018 16:17:36 -0800 Subject: [PATCH] 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 Reported-by: "zhangyi (F)" Reviewed-by: Ross Zwisler Acked-by: Kirill A. Shutemov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/dax.c | 19 ++++++------------- include/linux/mm.h | 26 ++++++++++++++++---------- mm/khugepaged.c | 3 +-- mm/memory.c | 43 +++++++++++++++++++++++++++++++------------ mm/nommu.c | 7 ------- mm/truncate.c | 23 +++++++---------------- 6 files changed, 61 insertions(+), 60 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index c2ebf10b70da..6ee6f7e24f5a 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -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 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, * 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) { diff --git a/include/linux/mm.h b/include/linux/mm.h index 7fc92384977e..173d2484f6e3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -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, diff --git a/mm/khugepaged.c b/mm/khugepaged.c index ea4ff259b671..1cd18e4347fe 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -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); diff --git a/mm/memory.c b/mm/memory.c index 82a0577933aa..a6e5d6ac5d24 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -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); diff --git a/mm/nommu.c b/mm/nommu.c index 17c00d93de2e..4b9864b17cb0 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -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(); diff --git a/mm/truncate.c b/mm/truncate.c index e4b4cf0f4070..c34e2fd4f583 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -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);