[PATCH v2] spi: rockchip-sfc: skip DMA cleanup in PIO mode

[Myeonghun Pak]

With rockchip,sfc-no-dma, probe skips allocating and mapping the transfer
buffer. However, controller registration failure and driver removal still
call dma_unmap_single() for that nonexistent mapping.

Guard the DMA mapping and buffer cleanup with use_dma. Keep the existing
cleanup for allocation and mapping failures on the DMA path.

This issue was identified during our ongoing static-analysis research while
reviewing kernel code.

Fixes: ee795e82e101 ("spi: rockchip-sfc: Fix DMA-API usage")
Assisted-by: OpenAI:GPT-5.6
Co-developed-by: Ijae Kim <ae878000@xxxxxxxxx>
Signed-off-by: Ijae Kim <ae878000@xxxxxxxxx>
Signed-off-by: Myeonghun Pak <mhun512@xxxxxxxxx>
---
Changes in v2:
- Guard the cleanup calls directly instead of jumping between error labels,
  as suggested by Mark Brown.

 drivers/spi/spi-rockchip-sfc.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-rockchip-sfc.c b/drivers/spi/spi-rockchip-sfc.c
index 662a994da60beca33358dc6af09017e88771d017..bc5537aee449e0c33c2d6ecf9d57205d432ec7b6 100644
--- a/drivers/spi/spi-rockchip-sfc.c
+++ b/drivers/spi/spi-rockchip-sfc.c
@@ -719,10 +719,12 @@ static int rockchip_sfc_probe(struct platform_device *pdev)
 
 	return 0;
 err_register:
-	dma_unmap_single(dev, sfc->dma_buffer, sfc->max_iosize,
-			 DMA_BIDIRECTIONAL);
+	if (sfc->use_dma)
+		dma_unmap_single(dev, sfc->dma_buffer, sfc->max_iosize,
+				 DMA_BIDIRECTIONAL);
 err_dma_map:
-	free_pages((unsigned long)sfc->buffer, get_order(sfc->max_iosize));
+	if (sfc->use_dma)
+		free_pages((unsigned long)sfc->buffer, get_order(sfc->max_iosize));
 err_dma:
 	pm_runtime_get_sync(dev);
 	pm_runtime_put_noidle(dev);
@@ -743,9 +745,11 @@ static void rockchip_sfc_remove(struct platform_device *pdev)
 	struct spi_controller *host = sfc->host;
 
 	spi_unregister_controller(host);
-	dma_unmap_single(&pdev->dev, sfc->dma_buffer, sfc->max_iosize,
-			 DMA_BIDIRECTIONAL);
-	free_pages((unsigned long)sfc->buffer, get_order(sfc->max_iosize));
+	if (sfc->use_dma) {
+		dma_unmap_single(&pdev->dev, sfc->dma_buffer, sfc->max_iosize,
+				 DMA_BIDIRECTIONAL);
+		free_pages((unsigned long)sfc->buffer, get_order(sfc->max_iosize));
+	}
 
 	clk_disable_unprepare(sfc->clk);
 	clk_disable_unprepare(sfc->hclk);
-- 
2.53.0