dmaengine: avoid map_cnt overflow with CONFIG_DMA_ENGINE_RAID

When CONFIG_DMA_ENGINE_RAID is enabled, unmap pool size can reach to
256. But in struct dmaengine_unmap_data, map_cnt is only u8, wrapping
to 0, if the unmap pool is maximally used. This triggers BUG() when
struct dmaengine_unmap_data is freed. Use u16 to fix the problem.

Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index f838764993eb..861be5cab1df 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -470,7 +470,11 @@ typedef void (*dma_async_tx_callback_result)(void *dma_async_param,
                                 const struct dmaengine_result *result);
 
 struct dmaengine_unmap_data {
+#if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
+        u16 map_cnt;
+#else
         u8 map_cnt;
+#endif
         u8 to_cnt;
         u8 from_cnt;
         u8 bidi_cnt;