From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Fri, 14 Aug 2015 12:58:50 +0000 (+0200)
Subject: s390/mm: simplify page table alloc/free code
X-Git-Tag: omap-for-v4.3/fixes-merge-window~38^2~6
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=78fb907626dccfeee6f4213c649606e9ba49c6bc;p=pandora-kernel.git

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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