1 files changed, 24 insertions, 23 deletions

diff --git a/kernel/dma-coherent.c b/kernel/dma-coherent.c
index 038707404b76..962a3b574f21 100644
--- a/kernel/dma-coherent.c
+++ b/kernel/dma-coherent.c
@@ -98,7 +98,7 @@ EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
  * @size:       size of requested memory area
  * @dma_handle: This will be filled with the correct dma handle
  * @ret:        This pointer will be filled with the virtual address
- *              to allocated area.
+ *              to allocated area.
  *
  * This function should be only called from per-arch dma_alloc_coherent()
  * to support allocation from per-device coherent memory pools.
@@ -118,31 +118,32 @@ int dma_alloc_from_coherent(struct device *dev, ssize_t size,
         mem = dev->dma_mem;
         if (!mem)
                 return 0;
-        if (unlikely(size > mem->size))
-                return 0;
+
+        *ret = NULL;
+
+        if (unlikely(size > (mem->size << PAGE_SHIFT)))
+                goto err;
 
         pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
-        if (pageno >= 0) {
-                /*
-                 * Memory was found in the per-device arena.
-                 */
-                *dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
-                *ret = mem->virt_base + (pageno << PAGE_SHIFT);
-                memset(*ret, 0, size);
-        } else if (mem->flags & DMA_MEMORY_EXCLUSIVE) {
-                /*
-                 * The per-device arena is exhausted and we are not
-                 * permitted to fall back to generic memory.
-                 */
-                *ret = NULL;
-        } else {
-                /*
-                 * The per-device arena is exhausted and we are
-                 * permitted to fall back to generic memory.
-                 */
-                 return 0;
-        }
+        if (unlikely(pageno < 0))
+                goto err;
+
+        /*
+         * Memory was found in the per-device area.
+         */
+        *dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
+        *ret = mem->virt_base + (pageno << PAGE_SHIFT);
+        memset(*ret, 0, size);
+
         return 1;
+
+err:
+        /*
+         * In the case where the allocation can not be satisfied from the
+         * per-device area, try to fall back to generic memory if the
+         * constraints allow it.
+         */
+        return mem->flags & DMA_MEMORY_EXCLUSIVE;
 }
 EXPORT_SYMBOL(dma_alloc_from_coherent);