From 14ef1fc72a3e86cea6498193c5e04b4619cb8622 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 5 Mar 2019 15:44:08 -0800 Subject: [PATCH] mm/filemap.c: remove redundant test from find_get_pages_contig After we establish a reference on the page, we check the pointer continues to be in the correct position in i_pages. Checking page->index afterwards is unnecessary; if it were to change, then the pointer to it from the page cache would also move. The check used to be done before grabbing a reference on the page which was racy (see commit 9cbb4cb21b19f ("mm: find_get_pages_contig fixlet")), but nobody noticed that moving the check after grabbing the reference was redundant. Link: http://lkml.kernel.org/r/20190107200224.13260-1-willy@infradead.org Signed-off-by: Matthew Wilcox Reviewed-by: Andrew Morton Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/filemap.c | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 9f5e323e883e..935fbc29aeb1 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1837,16 +1837,6 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, if (unlikely(page != xas_reload(&xas))) goto put_page; - /* - * must check mapping and index after taking the ref. - * otherwise we can get both false positives and false - * negatives, which is just confusing to the caller. - */ - if (!page->mapping || page_to_pgoff(page) != xas.xa_index) { - put_page(page); - break; - } - pages[ret] = page; if (++ret == nr_pages) break; -- GitLab