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Subject[PATCH] mm: mmap: remove verify_mm_writelocked()
Date
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.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
---
mm/mmap.c | 16 ----------------
1 file changed, 16 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index f7cd9cb966c0..1cee506494d2 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2910,16 +2910,6 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
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
@@ -2946,12 +2936,6 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
if (error)
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
*/
--
2.17.0
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