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Patch "dmaengine: fsl-edma: disable clks on all error paths" has been added to the 4.14-stable tree

PATCH [email protected] 1 participant 1 message Feb 28, 2018

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This is a note to let you know that I've just added the patch titled

dmaengine: fsl-edma: disable clks on all error paths

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
dmaengine-fsl-edma-disable-clks-on-all-error-paths.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From foo@baz Wed Feb 28 16:23:28 CET 2018

From: Andreas Platschek <[email protected]>
Date: Thu, 14 Dec 2017 12:50:51 +0100
Subject: dmaengine: fsl-edma: disable clks on all error paths

From: Andreas Platschek <[email protected]>

[ Upstream commit 2610acf46b9ed528ec2cacd717bc9d354e452b73 ]

Previously enabled clks are only disabled if clk_prepare_enable() fails. However, there are other error paths were the previously enabled clocks are not disabled.

To fix the problem, fsl_disable_clocks() now takes the number of clocks that shall be disabled + unprepared. For existing calls were all clocks were already successfully prepared + enabled, DMAMUX_NR is passed to disable + unprepare all clocks.

In error paths were only some clocks were successfully prepared + enabled the loop counter is passed, in order to disable + unprepare all successfully prepared + enabled clocks.

Found by Linux Driver Verification project (linuxtesting.org).

---
 drivers/dma/fsl-edma.c |   28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)
drivers/dma/fsl-edma.c +14 -14
@@ -863,11 +863,11 @@ static void fsl_edma_irq_exit(
 	}
 }
 
-static void fsl_disable_clocks(struct fsl_edma_engine *fsl_edma)
+static void fsl_disable_clocks(struct fsl_edma_engine *fsl_edma, int nr_clocks)
 {
 	int i;
 
-	for (i = 0; i < DMAMUX_NR; i++)
+	for (i = 0; i < nr_clocks; i++)
 		clk_disable_unprepare(fsl_edma->muxclk[i]);
 }
 
@@ -904,25 +904,25 @@ static int fsl_edma_probe(struct platfor
 
 		res = platform_get_resource(pdev, IORESOURCE_MEM, 1 + i);
 		fsl_edma->muxbase[i] = devm_ioremap_resource(&pdev->dev, res);
-		if (IS_ERR(fsl_edma->muxbase[i]))
+		if (IS_ERR(fsl_edma->muxbase[i])) {
+			/* on error: disable all previously enabled clks */
+			fsl_disable_clocks(fsl_edma, i);
 			return PTR_ERR(fsl_edma->muxbase[i]);
+		}
 
 		sprintf(clkname, "dmamux%d", i);
 		fsl_edma->muxclk[i] = devm_clk_get(&pdev->dev, clkname);
 		if (IS_ERR(fsl_edma->muxclk[i])) {
 			dev_err(&pdev->dev, "Missing DMAMUX block clock.\n");
+			/* on error: disable all previously enabled clks */
+			fsl_disable_clocks(fsl_edma, i);
 			return PTR_ERR(fsl_edma->muxclk[i]);
 		}
 
 		ret = clk_prepare_enable(fsl_edma->muxclk[i]);
-		if (ret) {
-			/* disable only clks which were enabled on error */
-			for (; i >= 0; i--)
-				clk_disable_unprepare(fsl_edma->muxclk[i]);
-
-			dev_err(&pdev->dev, "DMAMUX clk block failed.\n");
-			return ret;
-		}
+		if (ret)
+			/* on error: disable all previously enabled clks */
+			fsl_disable_clocks(fsl_edma, i);
 
 	}
 
@@ -976,7 +976,7 @@ static int fsl_edma_probe(struct platfor
 	if (ret) {
 		dev_err(&pdev->dev,
 			"Can't register Freescale eDMA engine. (%d)\n", ret);
-		fsl_disable_clocks(fsl_edma);
+		fsl_disable_clocks(fsl_edma, DMAMUX_NR);
 		return ret;
 	}
 
@@ -985,7 +985,7 @@ static int fsl_edma_probe(struct platfor
 		dev_err(&pdev->dev,
 			"Can't register Freescale eDMA of_dma. (%d)\n", ret);
 		dma_async_device_unregister(&fsl_edma->dma_dev);
-		fsl_disable_clocks(fsl_edma);
+		fsl_disable_clocks(fsl_edma, DMAMUX_NR);
 		return ret;
 	}
 
@@ -1015,7 +1015,7 @@ static int fsl_edma_remove(struct platfo
 	fsl_edma_cleanup_vchan(&fsl_edma->dma_dev);
 	of_dma_controller_free(np);
 	dma_async_device_unregister(&fsl_edma->dma_dev);
-	fsl_disable_clocks(fsl_edma);
+	fsl_disable_clocks(fsl_edma, DMAMUX_NR);
 
 	return 0;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/dmaengine-fsl-edma-disable-clks-on-all-error-paths.patch