linux-kernel - [PATCH v2] dma: mic_x100_dma: use devm

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Message-Id: <20180822024027.8984-1-sjhuang@iluvatar.ai>
Date:   Wed, 22 Aug 2018 10:40:27 +0800
From:   Huang Shijie <sjhuang@...vatar.ai>
To:     vkoul@...nel.org
Cc:     sudeep.dutt@...el.com, ashutosh.dixit@...el.com,
        dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org,
        Huang Shijie <sjhuang@...vatar.ai>
Subject: [PATCH v2] dma: mic_x100_dma: use devm_kzalloc to fix an issue

The following patch introduced an issue.
    commit f6206f00d8c5 ("dmaengine: mic_x100_dma: use the new helper to simplify the code")

This issue is :

	kfree(mic_dma_dev)
	.....
	dma_async_device_unregister(mic_dma_dev->device);

Free the memory, and use it again.

So use devm_kzalloc to allocate mic_dma_dev to fix it.

When the Devres try to release the resources, it will call release at the
following order:

	dma_async_device_unregister(mic_dma_dev->device);
	.....
	kfree(mic_dma_dev)

Fixes: f6206f00d8c5 ("dmaengine: mic_x100_dma: use the new helper to simplify the code")
Signed-off-by: Huang Shijie <sjhuang@...vatar.ai>
---
v1 --> v2:
     Change the commit message and title
---
 drivers/dma/mic_x100_dma.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/dma/mic_x100_dma.c b/drivers/dma/mic_x100_dma.c
index b76cb17d879c..adfd316db1a8 100644
--- a/drivers/dma/mic_x100_dma.c
+++ b/drivers/dma/mic_x100_dma.c
@@ -639,7 +639,7 @@ static struct mic_dma_device *mic_dma_dev_reg(struct mbus_device *mbdev,
 	int ret;
 	struct device *dev = &mbdev->dev;
 
-	mic_dma_dev = kzalloc(sizeof(*mic_dma_dev), GFP_KERNEL);
+	mic_dma_dev = devm_kzalloc(dev, sizeof(*mic_dma_dev), GFP_KERNEL);
 	if (!mic_dma_dev) {
 		ret = -ENOMEM;
 		goto alloc_error;
@@ -664,7 +664,6 @@ static struct mic_dma_device *mic_dma_dev_reg(struct mbus_device *mbdev,
 reg_error:
 	mic_dma_uninit(mic_dma_dev);
 init_error:
-	kfree(mic_dma_dev);
 	mic_dma_dev = NULL;
 alloc_error:
 	dev_err(dev, "Error at %s %d ret=%d\n", __func__, __LINE__, ret);
@@ -674,7 +673,6 @@ static struct mic_dma_device *mic_dma_dev_reg(struct mbus_device *mbdev,
 static void mic_dma_dev_unreg(struct mic_dma_device *mic_dma_dev)
 {
 	mic_dma_uninit(mic_dma_dev);
-	kfree(mic_dma_dev);
 }
 
 /* DEBUGFS CODE */
-- 
2.17.1