From: Sumit Bhattacharya <[email protected]>

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 3611553). Signed-off-by: Sumit Bhattacharya <[email protected]> Signed-off-by: Stephen Warren <[email protected]>
cybik · Nov 6, 2011 · b736010 · b736010
1 parent dd29588
commit b736010
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
@@ -289,6 +289,13 @@ __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_HUGETLB_PAGE. */
+	gfp &= ~(__GFP_COMP);
+
 	*handle = ~0;
 	size = PAGE_ALIGN(size);