Re: [PATCH 16/25] device-dax: use the dev_pagemap internal refcount

From: Dan Williams
Date: Fri Jun 28 2019 - 15:14:57 EST

On Fri, Jun 28, 2019 at 12:02 PM Christoph Hellwig <hch@xxxxxx> wrote:
> On Fri, Jun 28, 2019 at 11:59:19AM -0700, Dan Williams wrote:
> > It's a bug that the call to put_devmap_managed_page() was gated by
> > MEMORY_DEVICE_PUBLIC in release_pages(). That path is also applicable
> > to MEMORY_DEVICE_FSDAX because it needs to trigger the ->page_free()
> > callback to wake up wait_on_var() via fsdax_pagefree().
> >
> > So I guess you could argue that the MEMORY_DEVICE_PUBLIC removal patch
> > left the original bug in place. In that sense we're no worse off, but
> > since we know about the bug, the fix and the patches have not been
> > applied yet, why not fix it now?
> The fix it now would simply be to apply Ira original patch now, but
> given that we are at -rc6 is this really a good time? And if we don't
> apply it now based on the quilt based -mm worflow it just seems a lot
> easier to apply it after my series. Unless we want to include it in
> the series, in which case I can do a quick rebase, we'd just need to
> make sure Andrew pulls it from -mm.

I believe -mm auto drops patches when they appear in the -next
baseline. So it should "just work" to pull it into the series and send
it along for -next inclusion.