linux-kernel - [PATCH v2 2/2] i2c: lpi2c: Use cleanup helper for dma_async_tx

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Message-Id: <20251003-dma_chan_free-v2-2-564946b6c563@nxp.com>
Date: Fri, 03 Oct 2025 12:26:50 -0400
From: Frank Li <Frank.Li@....com>
To: Vinod Koul <vkoul@...nel.org>, Dong Aisheng <aisheng.dong@....com>, 
 Andi Shyti <andi.shyti@...nel.org>, Shawn Guo <shawnguo@...nel.org>, 
 Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>
Cc: dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-i2c@...r.kernel.org, imx@...ts.linux.dev, 
 linux-arm-kernel@...ts.infradead.org, carlos.song@....com, 
 Frank Li <Frank.Li@....com>
Subject: [PATCH v2 2/2] i2c: lpi2c: Use cleanup helper for
 dma_async_tx_descriptor error handling

Use the cleanup helper to simplify dma_async_tx_descriptor error handling.

No functional change.

Signed-off-by: Frank Li <Frank.Li@....com>
---
change v2
 need goto unmap buffer.

desc_prepare_err_exit:
        dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
                         dma->rx_cmd_buf_len, DMA_TO_DEVICE);
        return -EINVAL;

submit_err_exit:
        dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
                         dma->rx_cmd_buf_len, DMA_TO_DEVICE);
        dmaengine_desc_free(rx_cmd_desc)

auto cleanup by __free, so whole error path submit_err_exit can be removed
and use desc_prepare_err_exit label.
---
 drivers/i2c/busses/i2c-imx-lpi2c.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
index 03b5a7e8c361abe1d75fb4d31f9614bbc6387d93..e31c2d81f59f18a09d34f79896a7fa4bb83c0a12 100644
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -722,7 +722,7 @@ static void lpi2c_dma_callback(void *data)
 
 static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
 {
-	struct dma_async_tx_descriptor *rx_cmd_desc;
+	struct dma_async_tx_descriptor *rx_cmd_desc __free(dma_async_tx_descriptor) = NULL;
 	struct lpi2c_imx_dma *dma = lpi2c_imx->dma;
 	struct dma_chan *txchan = dma->chan_tx;
 	dma_cookie_t cookie;
@@ -746,10 +746,11 @@ static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
 	cookie = dmaengine_submit(rx_cmd_desc);
 	if (dma_submit_error(cookie)) {
 		dev_err(&lpi2c_imx->adapter.dev, "submitting DMA failed, use pio\n");
-		goto submit_err_exit;
+		goto desc_prepare_err_exit;
 	}
 
 	dma_async_issue_pending(txchan);
+	retain_and_null_ptr(rx_cmd_desc);
 
 	return 0;
 
@@ -757,12 +758,6 @@ static int lpi2c_dma_rx_cmd_submit(struct lpi2c_imx_struct *lpi2c_imx)
 	dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
 			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
 	return -EINVAL;
-
-submit_err_exit:
-	dma_unmap_single(txchan->device->dev, dma->dma_tx_addr,
-			 dma->rx_cmd_buf_len, DMA_TO_DEVICE);
-	dmaengine_desc_free(rx_cmd_desc);
-	return -EINVAL;
 }
 
 static int lpi2c_dma_submit(struct lpi2c_imx_struct *lpi2c_imx)

-- 
2.34.1