From 977fbdcd5986c9ff700bf276644d2b1973a53348 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Wed, 31 Jan 2018 16:17:36 -0800 Subject: 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 --- mm/khugepaged.c | 3 +-- mm/memory.c | 43 +++++++++++++++++++++++++++++++------------ mm/nommu.c | 7 ------- mm/truncate.c | 23 +++++++---------------- 4 files changed, 39 insertions(+), 37 deletions(-) (limited to '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); -- cgit v1.2.3