[PATCH v2] mtd: rawnand: lpc32xx_slc: fail DMA transfer on completion timeout

lpc32xx_xmit_dma() waits for the DMA completion callback but ignores
wait_for_completion_timeout(). A timed out DMA transfer is therefore
unmapped and reported as successful to the NAND read/write path.

Return -ETIMEDOUT when the completion wait expires. Terminate the DMA
channel before unmapping the scatterlist so the timed out transfer cannot
continue to access the buffer after the error is returned.

Fixes: 2944a44da09e ("mtd: add LPC32xx SLC NAND driver")
Cc: [email protected]
Reviewed-by: Vladimir Zapolskiy <[email protected]>
Signed-off-by: Pengpeng Hou <[email protected]>
---
Changes since v1: https://lore.kernel.org/all/[email protected]/
- add Fixes and Cc stable tags as requested by Miquel
- carry Vladimir's Reviewed-by tag

 drivers/mtd/nand/raw/lpc32xx_slc.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/raw/lpc32xx_slc.c b/drivers/mtd/nand/raw/lpc32xx_slc.c
index 3ca30e7dce33..10c8080207f4 100644
--- a/drivers/mtd/nand/raw/lpc32xx_slc.c
+++ b/drivers/mtd/nand/raw/lpc32xx_slc.c
@@ -430,6 +430,7 @@ static int lpc32xx_xmit_dma(struct mtd_info *mtd, dma_addr_t dma,
 	struct dma_async_tx_descriptor *desc;
 	int flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
 	int res;
+	unsigned long time_left;
 
 	host->dma_slave_config.direction = dir;
 	host->dma_slave_config.src_addr = dma;
@@ -467,12 +468,19 @@ static int lpc32xx_xmit_dma(struct mtd_info *mtd, dma_addr_t dma,
 	dmaengine_submit(desc);
 	dma_async_issue_pending(host->dma_chan);
 
-	wait_for_completion_timeout(&host->comp, msecs_to_jiffies(1000));
+	time_left = wait_for_completion_timeout(&host->comp,
+						msecs_to_jiffies(1000));
+	if (!time_left) {
+		dmaengine_terminate_sync(host->dma_chan);
+		res = -ETIMEDOUT;
+	} else {
+		res = 0;
+	}
 
 	dma_unmap_sg(host->dma_chan->device->dev, &host->sgl, 1,
 		     DMA_BIDIRECTIONAL);
 
-	return 0;
+	return res;
 out1:
 	dma_unmap_sg(host->dma_chan->device->dev, &host->sgl, 1,
 		     DMA_BIDIRECTIONAL);
-- 
2.53.0


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