mtrr, x86: fix MTRR lookup to handle inclusive entry

mtrr, x86: fix MTRR lookup to handle inclusive entry

When an MTRR entry is inclusive to a requested range, i.e.  the start and
end of the request are not within the MTRR entry range but the range
contains the MTRR entry entirely, __mtrr_type_lookup() ignores such a case
because both start_state and end_state are set to zero.

This bug can cause the following issues:

1) reserve_memtype() tracks an effective memory type in case a request
   type is WB (ex.  /dev/mem blindly uses WB).  Missing to track with its
   effective type causes a subsequent request to map the same range with
   the effective type to fail.

2) pud_set_huge() and pmd_set_huge() check if a requested range has any
   overlap with MTRRs.  Missing to detect an overlap may cause a
   performance penalty or undefined behavior.

This patch fixes the bug by adding a new flag, 'inclusive', to detect the
inclusive case.  This case is then handled in the same way as
(!start_state && end_state).  With this fix, __mtrr_type_lookup() handles
the inclusive case properly.

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Robert Elliott <Elliott@hp.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>