Michal Nazarewicz [off-list ref] writes:

On Fri, Jun 28 2013, Aneesh Kumar K.V wrote:

quoted

From: "Aneesh Kumar K.V" <redacted>

We want to use CMA for allocating hash page table and real mode area for
PPC64. Hence move DMA contiguous related changes into a seperate config
so that ppc64 can enable CMA without requiring DMA contiguous.

Signed-off-by: Aneesh Kumar K.V <redacted>

Acked-by: Michal Nazarewicz <redacted>

quoted

diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 07abd9d..74b7c98 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig

@@ -202,11 +202,10 @@ config DMA_SHARED_BUFFER
 	  APIs extension; the file's descriptor can then be passed on to other
 	  driver.
 
-config CMA
-	bool "Contiguous Memory Allocator"
-	depends on HAVE_DMA_CONTIGUOUS && HAVE_MEMBLOCK
-	select MIGRATION
-	select MEMORY_ISOLATION
+config DMA_CMA
+	bool "DMA Contiguous Memory Allocator"
+	depends on HAVE_DMA_CONTIGUOUS
+	select CMA

Just to be on the safe side, I'd add

	depends on HAVE_MEMBLOCK

or change this so that it does not select CMA but depends on CMA.

updated this to 

+config DMA_CMA
+	bool "DMA Contiguous Memory Allocator"
+	depends on HAVE_DMA_CONTIGUOUS && CMA

quoted

 	help
 	  This enables the Contiguous Memory Allocator which allows drivers
 	  to allocate big physically-contiguous blocks of memory for use with

@@ -215,17 +214,7 @@ config CMA
 	  For more information see <include/linux/dma-contiguous.h>.
 	  If unsure, say "n".
 
-if CMA
-
-config CMA_DEBUG
-	bool "CMA debug messages (DEVELOPMENT)"
-	depends on DEBUG_KERNEL
-	help
-	  Turns on debug messages in CMA.  This produces KERN_DEBUG
-	  messages for every CMA call as well as various messages while
-	  processing calls such as dma_alloc_from_contiguous().
-	  This option does not affect warning and error messages.
-

Thanks
-aneesh