From 9cabf929e7d92139a7d1ef3e517ad57dfece4739 Mon Sep 17 00:00:00 2001 From: Yangtao Li Date: Fri, 28 Dec 2018 00:34:09 -0800 Subject: [PATCH] mm/mmap.c: remove verify_mm_writelocked() We should get rid of this function. It no longer serves its purpose. This is a historical artifact from 2005 where do_brk was called outside of the core mm. We do have a proper abstraction in vm_brk_flags and that one does the locking properly so there is no need to use this function. Link: http://lkml.kernel.org/r/20181108174856.10811-1-tiny.windzz@gmail.com Signed-off-by: Yangtao Li Acked-by: Michal Hocko Acked-by: David Rientjes Cc: Dan Williams Cc: Dominik Brodowski Cc: Dave Hansen Cc: David Woodhouse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 16 ---------------- 1 file changed, 16 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 7bb6438..f901065 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2973,16 +2973,6 @@ out: return ret; } -static inline void verify_mm_writelocked(struct mm_struct *mm) -{ -#ifdef CONFIG_DEBUG_VM - if (unlikely(down_read_trylock(&mm->mmap_sem))) { - WARN_ON(1); - up_read(&mm->mmap_sem); - } -#endif -} - /* * this is really a simplified "do_mmap". it only handles * anonymous maps. eventually we may be able to do some @@ -3010,12 +3000,6 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla return error; /* - * mm->mmap_sem is required to protect against another thread - * changing the mappings in case we sleep. - */ - verify_mm_writelocked(mm); - - /* * Clear old maps. this also does some error checking for us */ while (find_vma_links(mm, addr, addr + len, &prev, &rb_link, -- 2.7.4