[PATCH] hugepage: is_aligned_hugepage_range() cleanup

[PATCH] hugepage: is_aligned_hugepage_range() cleanup

Quite a long time back, prepare_hugepage_range() replaced
is_aligned_hugepage_range() as the callback from mm/mmap.c to arch code to
verify if an address range is suitable for a hugepage mapping.
is_aligned_hugepage_range() stuck around, but only to implement
prepare_hugepage_range() on archs which didn't implement their own.

Most archs (everything except ia64 and powerpc) used the same
implementation of is_aligned_hugepage_range().  On powerpc, which
implements its own prepare_hugepage_range(), the custom version was never
used.

In addition, "is_aligned_hugepage_range()" was a bad name, because it
suggests it returns true iff the given range is a good hugepage range,
whereas in fact it returns 0-or-error (so the sense is reversed).

This patch cleans up by abolishing is_aligned_hugepage_range().  Instead
prepare_hugepage_range() is defined directly.  Most archs use the default
version, which simply checks the given region is aligned to the size of a
hugepage.  ia64 and powerpc define custom versions.  The ia64 one simply
checks that the range is in the correct address space region in addition to
being suitably aligned.  The powerpc version (just as previously) checks
for suitable addresses, and if necessary performs low-level MMU frobbing to
set up new areas for use by hugepages.

No libhugetlbfs testsuite regressions on ppc64 (POWER5 LPAR).

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>