From 9943242ca468149c4ce30d4633524c0866d4a87b Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 4 Sep 2015 15:48:13 -0700 Subject: [PATCH] mremap: simplify the "overlap" check in mremap_to() Minor, but this check is overcomplicated. Two half-intervals do NOT overlap if END1 <= START2 || END2 <= START1, mremap_to() just needs to negate this check. Signed-off-by: Oleg Nesterov Acked-by: David Rientjes Cc: Benjamin LaHaise Cc: Hugh Dickins Cc: Jeff Moyer Cc: Kirill A. Shutemov Cc: Laurent Dufour Cc: Pavel Emelyanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mremap.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/mm/mremap.c b/mm/mremap.c index d3f42bece564..5a71cce8c6ea 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -407,13 +407,8 @@ static unsigned long mremap_to(unsigned long addr, unsigned long old_len, if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len) goto out; - /* Check if the location we're moving into overlaps the - * old location at all, and fail if it does. - */ - if ((new_addr <= addr) && (new_addr+new_len) > addr) - goto out; - - if ((addr <= new_addr) && (addr+old_len) > new_addr) + /* Ensure the old/new locations do not overlap */ + if (addr + old_len > new_addr && new_addr + new_len > addr) goto out; ret = do_munmap(mm, new_addr, new_len); -- 2.20.1