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.
