A couple of questions

[Neil Booth <NeilB@earthling.net>]

I have a couple of questions about do_wp_page; I hope they're welcome
here.

1) do_wp_page has most execution paths doing an unlock_kernel() but
there are a couple that don't. Why isn't this inconsistent? e.g. any of
the branches that call end_wp_page do not unlock the kernel. What am I
missing? Is it that these branches only happen if we slept while getting
the free page, and sleeping always unlocks the kernel?

2) The last 2 of the 3 branches to end_wp_page seem to me to be
impossible code paths.

	if (!pte_present(pte))
		goto end_wp_page;
	if (pte_write(pte))
		goto end_wp_page;

At entry, pte (= *page_table) is present and not writable as this is the
only way do_wp_page gets called from handle_pte_fault (and we hold the
kernel lock so nothing else can change *page_table). Being a local
variable, it contents cannot change, so why these 2 tests?

Cheers,

Neil.
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