From: "Matthew Wilcox (Oracle)" willy@infradead.org
Commit 1b8ddbeeb9b819e62b7190115023ce858a159f5c upstream.
invalidate_inode_page() is the only caller of invalidate_complete_page() and inlining it reveals that the first check is unnecessary (because we hold the page locked, and we just retrieved the mapping from the page). Actually, it does make a difference, in that tail pages no longer fail at this check, so it's now possible to remove a tail page from a mapping.
Signed-off-by: Matthew Wilcox (Oracle) willy@infradead.org Reviewed-by: John Hubbard jhubbard@nvidia.com Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Roman Smirnov r.smirnov@omp.ru --- kernel/futex/core.c | 2 +- mm/truncate.c | 31 +++++-------------------------- 2 files changed, 6 insertions(+), 27 deletions(-)
diff --git a/kernel/futex/core.c b/kernel/futex/core.c index cde0ca876b93..cbbebc3de1d3 100644 --- a/kernel/futex/core.c +++ b/kernel/futex/core.c @@ -578,7 +578,7 @@ static int get_futex_key(u32 __user *uaddr, bool fshared, union futex_key *key, * found it, but truncated or holepunched or subjected to * invalidate_complete_page2 before we got the page lock (also * cases which we are happy to fail). And we hold a reference, - * so refcount care in invalidate_complete_page's remove_mapping + * so refcount care in invalidate_inode_page's remove_mapping * prevents drop_caches from setting mapping to NULL beneath us. * * The case we do have to guard against is when memory pressure made diff --git a/mm/truncate.c b/mm/truncate.c index 8914ca4ce4b1..03998fd86e4a 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -190,30 +190,6 @@ static void truncate_cleanup_page(struct page *page) ClearPageMappedToDisk(page); }
-/* - * This is for invalidate_mapping_pages(). That function can be called at - * any time, and is not supposed to throw away dirty pages. But pages can - * be marked dirty at any time too, so use remove_mapping which safely - * discards clean, unused pages. - * - * Returns non-zero if the page was successfully invalidated. - */ -static int -invalidate_complete_page(struct address_space *mapping, struct page *page) -{ - int ret; - - if (page->mapping != mapping) - return 0; - - if (page_has_private(page) && !try_to_release_page(page, 0)) - return 0; - - ret = remove_mapping(mapping, page); - - return ret; -} - int truncate_inode_page(struct address_space *mapping, struct page *page) { VM_BUG_ON_PAGE(PageTail(page), page); @@ -258,7 +234,10 @@ int invalidate_inode_page(struct page *page) return 0; if (page_mapped(page)) return 0; - return invalidate_complete_page(mapping, page); + if (page_has_private(page) && !try_to_release_page(page, 0)) + return 0; + + return remove_mapping(mapping, page); }
/** @@ -645,7 +624,7 @@ void invalidate_mapping_pagevec(struct address_space *mapping, }
/* - * This is like invalidate_complete_page(), except it ignores the page's + * This is like invalidate_inode_page(), except it ignores the page's * refcount. We do this because invalidate_inode_pages2() needs stronger * invalidation guarantees, and cannot afford to leave pages behind because * shrink_page_list() has a temp ref on them, or because they're transiently