[PATCH] dmaengine: do not allow access outside of unmap_pool

[Colin King <colin.king@canonical.com>]

From: Colin Ian King <colin.king@canonical.com>

When CONFIG_DMA_ENGINE_RAID is defined, unmap_pool[] is just 1
element in size, however, allows orders of 2..8 to access
outside unmap_pool and returns an invalid address. Ensure
we fall into the default path and report a BUG() when
CONFIG_DMA_ENGINE_RAID is defined and order is out of range.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/dma/dmaengine.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 8c9f45f..6027e66 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -1100,12 +1100,14 @@ static struct dmaengine_unmap_pool *__get_unmap_pool(int nr)
 	switch (order) {
 	case 0 ... 1:
 		return &unmap_pool[0];
+	#if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
 	case 2 ... 4:
 		return &unmap_pool[1];
 	case 5 ... 7:
 		return &unmap_pool[2];
 	case 8:
 		return &unmap_pool[3];
+	#endif
 	default:
 		BUG();
 		return NULL;
-- 
2.8.1