Re: [PATCH] Ensure that walk_page_range()'s start and end are page-aligned

From: Dan Smith
Date: Fri Feb 10 2012 - 15:23:28 EST


MN> Commit message says about walk_pte_range() but commit changes
MN> walk_page_range().

Yep, the issue occurs in walk_pte_range(). The goal was to ensure that
the external interface to it (which is walk_page_range()) does the check
and avoids doing the walk entirely. I think the expectation is that
walk_page_range() is used on aligned addresses. If we put the check in
walk_pte_range() then only walks with a pte_entry handler would fail on
unaligned addresses, which is potentially confusing.

MN> So why not change the condition to addr < end?

That would work, of course, but seems sloppier and less precise. The
existing code was clearly written expecting to walk aligned addresses.

--
Dan Smith
IBM Linux Technology Center
email: danms@xxxxxxxxxx
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