From ea2e7057c0234cfb8b09467d8f137760d371fc72 Mon Sep 17 00:00:00 2001
From: Sumit Bhattacharya <sumitb@nvidia.com>
Date: Thu, 24 Nov 2011 00:47:12 +0100
Subject: [PATCH] ARM: 7172/1: dma: Drop GFP_COMP for DMA memory allocations

dma_alloc_coherent wants to split pages after allocation in order to
reduce the memory footprint. This does not work well with GFP_COMP
pages, so drop this flag before allocation.

This patch is ported from arch/avr32
(commit 3611553ef985ef7c5863c8a94641738addd04cff).

[swarren: s/HUGETLB_PAGE/HUGETLBFS/ in comment, minor comment cleanup]

Signed-off-by: Sumit Bhattacharya <sumitb@nvidia.com>
Tested-by: Varun Colbert <vcolbert@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 arch/arm/mm/dma-mapping.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index ab584569930e..1aa664a1999f 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -332,6 +332,15 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
 	struct page *page;
 	void *addr;
 
+	/*
+	 * Following is a work-around (a.k.a. hack) to prevent pages
+	 * with __GFP_COMP being passed to split_page() which cannot
+	 * handle them.  The real problem is that this flag probably
+	 * should be 0 on ARM as it is not supported on this
+	 * platform; see CONFIG_HUGETLBFS.
+	 */
+	gfp &= ~(__GFP_COMP);
+
 	*handle = ~0;
 	size = PAGE_ALIGN(size);
 
-- 
2.20.1