From 78fb907626dccfeee6f4213c649606e9ba49c6bc Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Fri, 14 Aug 2015 14:58:50 +0200
Subject: [PATCH] s390/mm: simplify page table alloc/free code

With the removal of the dynamic reallocation of page tables for
KVM (see git commit 0b46e0a3ec0d7a04af6a091354f1b5e1b952d70a)
the page table allocation / freeing code can be simplified.

The page table free code can now use the alloc_pgste bit in the
mm context to decide if a page table is 2K or 4K, there is no mix
of different sized page tables anymore. This eliminates the need
to use "page->_mapcount == 0" to check for 4K page table.

Use the lower two bits in page->_mapcount to indicate which
2K fragments of the 4K page are in use.

As 31-bit support is gone, remove the two defines ALLOC_ORDER
and FRAG_MASK and use the constants directly where appropriate.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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