The patch titled
Subject: mm/mmap.c: remove verify_mm_writelocked()
has been added to the -mm tree. Its filename is
mm-mmap-remove-verify_mm_writelocked.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-mmap-remove-verify_mm_writelocked.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-mmap-remove-verify_mm_writelocked.patch
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------------------------------------------------------
From: Yangtao Li <tiny.windzz@xxxxxxxxx>
Subject: 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@xxxxxxxxx
Signed-off-by: Yangtao Li <tiny.windzz@xxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 16 ----------------
1 file changed, 16 deletions(-)
--- a/mm/mmap.c~mm-mmap-remove-verify_mm_writelocked
+++ a/mm/mmap.c
@@ -2962,16 +2962,6 @@ 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
@@ -2999,12 +2989,6 @@ static int do_brk_flags(unsigned long ad
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,
_
Patches currently in -mm which might be from tiny.windzz@xxxxxxxxx are
mm-slab-remove-unnecessary-unlikely.patch
mm-mmap-remove-verify_mm_writelocked.patch
