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: 2284354 ("dma: mv_xor: Add support for DMA_INTERRUPT")
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
Link: https://lore.kernel.org/r/20250701123753.46935-2-fourier.thomas@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: Thomas-fourier

drivers/dma/mv_xor.c

@@ -1061,8 +1061,16 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
 	 */
 	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
@@ -1071,8 +1079,10 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
 	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;
@@ -1155,6 +1165,13 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
 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);
 }