On Mon, May 21, 2018 at 03:25:24AM -0700, Matthew Wilcox wrote:
> On Sun, May 20, 2018 at 10:47:56PM -0600, Ross Zwisler wrote:
> > On Sat, Apr 14, 2018 at 07:13:07AM -0700, Matthew Wilcox wrote:
> > > From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
> > >
> > > Since the XArray is embedded in the struct address_space, this contains
> > > exactly as much entropy as the address of the mapping.
> >
> > I agree that they both have the same amount of entropy, but what's the
> > benefit? It doesn't seem like this changes any behavior, fixes any bugs or
> > makes things any simpler?
>
> This is a preparatory patch for some of the changes later in the series.
> It has no benefit in and of itself; the benefit comes later when we
> switch from dax_wake_mapping_entry() to dax_wake_entry():
>
> static void dax_wake_entry(struct xa_state *xas, bool wake_all)
>
> This switch could be left until the end; I can introduce dax_wake_entry()
> without this change:
>
> +static void dax_wake_entry(struct xa_state *xas, bool wake_all)
> +{
> + struct address_space *mapping = container_of(xas->xa,
> + struct address_space, i_pages);
> + return dax_wake_mapping_entry_waiter(mapping, xas->xa_index, NULL,
> + wake_all);
> +}
>
> and then cut everybody over in the final step.
>
> Or I can just explain in the changelog that it's a preparatory step.
Sure, just a note in the changelog saying that it's a preparatory step would
be good enough for me.
