On Wed, 10 Sep 2014 22:41:04 -0700 Peter Feiner [off-list ref] wrote:

On Wed, Sep 10, 2014 at 04:36:28PM -0700, Andrew Morton wrote:

quoted

On Wed, 10 Sep 2014 16:24:46 -0700 Peter Feiner [off-list ref] wrote:

quoted

@@ -1048,32 +1048,51 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
+	while (1) {
+		unsigned long vm_start = end;

Did you really mean to do that?  If so, perhaps a little comment to
explain how it works?

It's the same idea that I used in the pagemap_pte_hole patch that I submitted
today: if vma is NULL, then we fill in the pagemap from (addr) to (end) with
non-present pagemap entries. 

Should I submit a v2 with a comment?

I spent quite some time staring at that code wondering wtf, so anything
you can do to clarify it would be good.

I think a better name would be plain old "start", to communicate that
it's just a local convenience variable.  "vm_start" means "start of a
vma" and that isn't accurate in this context; in fact it is misleading.

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