linux-kernel - Re: [PATCH] mm/mmap: Don't unlock VMAs in remap_file

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Message-ID: <20201215154043.cqdr6pktkokz4hkz@revolver>
Date:   Tue, 15 Dec 2020 10:40:43 -0500
From:   "Liam R. Howlett" <Liam.Howlett@...cle.com>
To:     Matthew Wilcox <willy@...radead.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Andrew Morton <akpm@...gle.com>
Subject: Re: [PATCH] mm/mmap: Don't unlock VMAs in remap_file_pages()

* Matthew Wilcox <willy@...radead.org> [201215 09:50]:
> On Tue, Dec 15, 2020 at 09:13:00AM -0500, Liam R. Howlett wrote:
> > @@ -3025,25 +3025,6 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
> >  
> >  	flags &= MAP_NONBLOCK;
> >  	flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE;
> > -	if (vma->vm_flags & VM_LOCKED) {
> > -		struct vm_area_struct *tmp;
> > -		flags |= MAP_LOCKED;
> 
> I think you need to keep ^^^ that line because the vma needs to stay
> mlocked.
> 

Yes.  I missed that this is transferred through by calc_vm_flag_bits()
in do_mmap().  I will revise the patch.

Thanks,
Liam