From: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date: Mon, 7 Apr 2014 22:37:14 +0000 (-0700)
Subject: mm: disable split page table lock for !MMU
X-Git-Tag: v3.15-rc1~57^2~138
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=9164550ecd15253d72b5fe3b4baa9505c4b6fa1f;p=~emulex%2Finfiniband.git

mm: disable split page table lock for !MMU

There's no reason to enable split page table lock if don't have page
tables.

It also triggers build error at least on ARM since we don't define
pmd_page() for !MMU.

  In file included from arch/arm/kernel/asm-offsets.c:14:0:
  include/linux/mm.h: In function 'pte_lockptr':
  include/linux/mm.h:1392:2: error: implicit declaration of function 'pmd_page' [-Werror=implicit-function-declaration]
  include/linux/mm.h:1392:2: warning: passing argument 1 of 'ptlock_ptr' makes pointer from integer without a cast [enabled by default]
  include/linux/mm.h:1384:27: note: expected 'struct page *' but argument is of type 'int'

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/Kconfig b/mm/Kconfig
index 2888024e0b0..37fbe1ef523 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -216,6 +216,7 @@ config PAGEFLAGS_EXTENDED
 #
 config SPLIT_PTLOCK_CPUS
 	int
+	default "999999" if !MMU
 	default "999999" if ARM && !CPU_CACHE_VIPT
 	default "999999" if PARISC && !PA20
 	default "4"