[AVR32] 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 was forward-ported from BSP 2.0

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/avr32/mm/dma-coherent.c b/arch/avr32/mm/dma-coherent.c
index 177fea8f7b71..6d8c794c3b81 100644
--- a/arch/avr32/mm/dma-coherent.c
+++ b/arch/avr32/mm/dma-coherent.c
@@ -41,6 +41,13 @@ static struct page *__dma_alloc(struct device *dev, size_t size,
         struct page *page, *free, *end;
         int order;
 
+        /* 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 AVR32 as it is not supported on this
+         * platform--see CONFIG_HUGETLB_PAGE. */
+        gfp &= ~(__GFP_COMP);
+
         size = PAGE_ALIGN(size);
         order = get_order(size);