arm-nommu: remove the partial DMA_ATTR_NON_CONSISTENT support

The arm-nommu DMA code supports DMA_ATTR_NON_CONSISTENT allocations, but
does not provide a cache_sync operation.  This means any user of it
will never be able to actually transfer cache ownership and thus cause
coherency bugs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>

diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c
index f304b10e23a4cbfa9c3c89335dd917418f82c45f..bc003df45546fd2de0661d00d1196389c649f794 100644 (file)
--- a/arch/arm/mm/dma-mapping-nommu.c
+++ b/arch/arm/mm/dma-mapping-nommu.c
@@ -39,18 +39,7 @@ static void *arm_nommu_dma_alloc(struct device *dev, size_t size,
                                 unsigned long attrs)
 
 {
-       void *ret;
-
-       /*
-        * Try generic allocator first if we are advertised that
-        * consistency is not required.
-        */
-
-       if (attrs & DMA_ATTR_NON_CONSISTENT)
-               return dma_direct_alloc_pages(dev, size, dma_handle, gfp,
-                               attrs);
-
-       ret = dma_alloc_from_global_coherent(size, dma_handle);
+       void *ret = dma_alloc_from_global_coherent(size, dma_handle);
 
        /*
         * dma_alloc_from_global_coherent() may fail because:
@@ -70,16 +59,9 @@ static void arm_nommu_dma_free(struct device *dev, size_t size,
                               void *cpu_addr, dma_addr_t dma_addr,
                               unsigned long attrs)
 {
-       if (attrs & DMA_ATTR_NON_CONSISTENT) {
-               dma_direct_free_pages(dev, size, cpu_addr, dma_addr, attrs);
-       } else {
-               int ret = dma_release_from_global_coherent(get_order(size),
-                                                          cpu_addr);
-
-               WARN_ON_ONCE(ret == 0);
-       }
+       int ret = dma_release_from_global_coherent(get_order(size), cpu_addr);
 
-       return;
+       WARN_ON_ONCE(ret == 0);
 }
 
 static int arm_nommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,