Commit 9cabf929 authored Dec 28, 2018 by Yangtao Li Committed by Linus Torvalds Dec 28, 2018

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 <tiny.windzz@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 59e1a2f4

mm/mmap.c

+0 −16

Original line number	Diff line number	Diff line
		@@ -2973,16 +2973,6 @@ 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
		@@ -3009,12 +2999,6 @@ 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
		*/