dmaengine: mv_xor: Fix missing check after DMA map and missing unmap

The DMA map functions can fail and should be tested for errors.

In case of error, unmap the already mapped regions.

Fixes: 22843545b200 ("dma: mv_xor: Add support for DMA_INTERRUPT")
Signed-off-by: Thomas Fourier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/mv_xor.c

···
 	 */
 	mv_chan->dummy_src_addr = dma_map_single(dma_dev->dev,
 		mv_chan->dummy_src, MV_XOR_MIN_BYTE_COUNT, DMA_FROM_DEVICE);
+	if (dma_mapping_error(dma_dev->dev, mv_chan->dummy_src_addr))
+		return ERR_PTR(-ENOMEM);
+
 	mv_chan->dummy_dst_addr = dma_map_single(dma_dev->dev,
 		mv_chan->dummy_dst, MV_XOR_MIN_BYTE_COUNT, DMA_TO_DEVICE);
+	if (dma_mapping_error(dma_dev->dev, mv_chan->dummy_dst_addr)) {
+		ret = -ENOMEM;
+		goto err_unmap_src;
+	}
+
 
 	/* allocate coherent memory for hardware descriptors
 	 * note: writecombine gives slightly better performance, but
···
 	mv_chan->dma_desc_pool_virt =
 	  dma_alloc_wc(&pdev->dev, MV_XOR_POOL_SIZE, &mv_chan->dma_desc_pool,
 		       GFP_KERNEL);
-	if (!mv_chan->dma_desc_pool_virt)
-		return ERR_PTR(-ENOMEM);
+	if (!mv_chan->dma_desc_pool_virt) {
+		ret = -ENOMEM;
+		goto err_unmap_dst;
+	}
 
 	/* discover transaction capabilities from the platform data */
 	dma_dev->cap_mask = cap_mask;
···
 err_free_dma:
 	dma_free_coherent(&pdev->dev, MV_XOR_POOL_SIZE,
 			  mv_chan->dma_desc_pool_virt, mv_chan->dma_desc_pool);
+err_unmap_dst:
+	dma_unmap_single(dma_dev->dev, mv_chan->dummy_dst_addr,
+			 MV_XOR_MIN_BYTE_COUNT, DMA_TO_DEVICE);
+err_unmap_src:
+	dma_unmap_single(dma_dev->dev, mv_chan->dummy_src_addr,
+			 MV_XOR_MIN_BYTE_COUNT, DMA_FROM_DEVICE);
+
 	return ERR_PTR(ret);
 }