[PATCH v1 1/2] mfd: intel_quark_i2c_gpio: remove clock tree on error path

[PATCH v1 1/2] mfd: intel_quark_i2c_gpio: remove clock tree on error path

[Andy Shevchenko]

There is a potential resource leak in case when ->probe() fails. We have to
unregister and remove clock tree which is done here.

This is a follow up to previously pushed commit c4726abce63b ("mfd:
intel_quark_i2c_gpio: Use clkdev_create()") that prevents double free() when
clkdev_drop() followed by kfree() in devm_kcalloc() release stage.

I leave Fixes tag here, but the backporting will require to backport the commit
c4726abce63b ("mfd: intel_quark_i2c_gpio: Use clkdev_create()") first.

Fixes: 60ae5b9f5cdd (mfd: intel_quark_i2c_gpio: Add Intel Quark X1000 I2C-GPIO MFD Driver)
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/mfd/intel_quark_i2c_gpio.c | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/drivers/mfd/intel_quark_i2c_gpio.c b/drivers/mfd/intel_quark_i2c_gpio.c
index bdc5e27..43d8066 100644
--- a/drivers/mfd/intel_quark_i2c_gpio.c
+++ b/drivers/mfd/intel_quark_i2c_gpio.c
@@ -150,11 +150,10 @@ static void intel_quark_unregister_i2c_clk(struct pci_dev *pdev)
 {
 	struct intel_quark_mfd *quark_mfd = dev_get_drvdata(&pdev->dev);
 
-	if (!quark_mfd->i2c_clk || !quark_mfd->i2c_clk_lookup)
+	clk_unregister(quark_mfd->i2c_clk);
+	if (!quark_mfd->i2c_clk_lookup)
 		return;
-
 	clkdev_drop(quark_mfd->i2c_clk_lookup);
-	clk_unregister(quark_mfd->i2c_clk);
 }
 
 static int intel_quark_i2c_setup(struct pci_dev *pdev, struct mfd_cell *cell)
@@ -246,25 +245,33 @@ static int intel_quark_mfd_probe(struct pci_dev *pdev,
 	quark_mfd = devm_kzalloc(&pdev->dev, sizeof(*quark_mfd), GFP_KERNEL);
 	if (!quark_mfd)
 		return -ENOMEM;
+
 	quark_mfd->pdev = pdev;
+	dev_set_drvdata(&pdev->dev, quark_mfd);
 
 	ret = intel_quark_register_i2c_clk(quark_mfd);
 	if (ret)
-		return ret;
-
-	dev_set_drvdata(&pdev->dev, quark_mfd);
+		goto err_unregister_i2c_clk;
 
 	ret = intel_quark_i2c_setup(pdev, &intel_quark_mfd_cells[1]);
 	if (ret)
-		return ret;
+		goto err_unregister_i2c_clk;
 
 	ret = intel_quark_gpio_setup(pdev, &intel_quark_mfd_cells[0]);
 	if (ret)
-		return ret;
+		goto err_unregister_i2c_clk;
+
+	ret = mfd_add_devices(&pdev->dev, 0, intel_quark_mfd_cells,
+			      ARRAY_SIZE(intel_quark_mfd_cells), NULL, 0,
+			      NULL);
+	if (ret)
+		goto err_unregister_i2c_clk;
 
-	return mfd_add_devices(&pdev->dev, 0, intel_quark_mfd_cells,
-			       ARRAY_SIZE(intel_quark_mfd_cells), NULL, 0,
-			       NULL);
+	return 0;
+
+err_unregister_i2c_clk:
+	intel_quark_unregister_i2c_clk(pdev);
+	return ret;
 }
 
 static void intel_quark_mfd_remove(struct pci_dev *pdev)
-- 
2.7.0

[PATCH v1 2/2] mfd: intel_quark_i2c_gpio: switch to use struct device *

[Andy Shevchenko]

There is no need to pass struct pci_dev * to intel_quark_register_i2c_clk() and
intel_quark_unregister_i2c_clk(). Change the parameter to struct device *. As a
result store it in the private struct instead of struct pci_dev *.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/mfd/intel_quark_i2c_gpio.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/mfd/intel_quark_i2c_gpio.c b/drivers/mfd/intel_quark_i2c_gpio.c
index 43d8066..ca8751e 100644
--- a/drivers/mfd/intel_quark_i2c_gpio.c
+++ b/drivers/mfd/intel_quark_i2c_gpio.c
@@ -53,7 +53,7 @@
 #define INTEL_QUARK_I2C_CLK_HZ	33000000
 
 struct intel_quark_mfd {
-	struct pci_dev		*pdev;
+	struct device		*dev;
 	struct clk		*i2c_clk;
 	struct clk_lookup	*i2c_clk_lookup;
 };
@@ -123,12 +123,12 @@ static const struct pci_device_id intel_quark_mfd_ids[] = {
 };
 MODULE_DEVICE_TABLE(pci, intel_quark_mfd_ids);
 
-static int intel_quark_register_i2c_clk(struct intel_quark_mfd *quark_mfd)
+static int intel_quark_register_i2c_clk(struct device *dev)
 {
-	struct pci_dev *pdev = quark_mfd->pdev;
+	struct intel_quark_mfd *quark_mfd = dev_get_drvdata(dev);
 	struct clk *i2c_clk;
 
-	i2c_clk = clk_register_fixed_rate(&pdev->dev,
+	i2c_clk = clk_register_fixed_rate(dev,
 					  INTEL_QUARK_I2C_CONTROLLER_CLK, NULL,
 					  CLK_IS_ROOT, INTEL_QUARK_I2C_CLK_HZ);
 	if (IS_ERR(i2c_clk))
@@ -139,16 +139,16 @@ static int intel_quark_register_i2c_clk(struct intel_quark_mfd *quark_mfd)
 						INTEL_QUARK_I2C_CONTROLLER_CLK);
 
 	if (!quark_mfd->i2c_clk_lookup) {
-		dev_err(&pdev->dev, "Fixed clk register failed\n");
+		dev_err(dev, "Fixed clk register failed\n");
 		return -ENOMEM;
 	}
 
 	return 0;
 }
 
-static void intel_quark_unregister_i2c_clk(struct pci_dev *pdev)
+static void intel_quark_unregister_i2c_clk(struct device *dev)
 {
-	struct intel_quark_mfd *quark_mfd = dev_get_drvdata(&pdev->dev);
+	struct intel_quark_mfd *quark_mfd = dev_get_drvdata(dev);
 
 	clk_unregister(quark_mfd->i2c_clk);
 	if (!quark_mfd->i2c_clk_lookup)
@@ -246,10 +246,10 @@ static int intel_quark_mfd_probe(struct pci_dev *pdev,
 	if (!quark_mfd)
 		return -ENOMEM;
 
-	quark_mfd->pdev = pdev;
+	quark_mfd->dev = &pdev->dev;
 	dev_set_drvdata(&pdev->dev, quark_mfd);
 
-	ret = intel_quark_register_i2c_clk(quark_mfd);
+	ret = intel_quark_register_i2c_clk(&pdev->dev);
 	if (ret)
 		goto err_unregister_i2c_clk;
 
@@ -270,13 +270,13 @@ static int intel_quark_mfd_probe(struct pci_dev *pdev,
 	return 0;
 
 err_unregister_i2c_clk:
-	intel_quark_unregister_i2c_clk(pdev);
+	intel_quark_unregister_i2c_clk(&pdev->dev);
 	return ret;
 }
 
 static void intel_quark_mfd_remove(struct pci_dev *pdev)
 {
-	intel_quark_unregister_i2c_clk(pdev);
+	intel_quark_unregister_i2c_clk(&pdev->dev);
 	mfd_remove_devices(&pdev->dev);
 }
 
-- 
2.7.0

Re: [PATCH v1 1/2] mfd: intel_quark_i2c_gpio: remove clock tree on error path

[Stephen Boyd]

On 02/17, Andy Shevchenko wrote:
> diff --git a/drivers/mfd/intel_quark_i2c_gpio.c b/drivers/mfd/intel_quark_i2c_gpio.c
> index bdc5e27..43d8066 100644
> --- a/drivers/mfd/intel_quark_i2c_gpio.c
> +++ b/drivers/mfd/intel_quark_i2c_gpio.c
> @@ -150,11 +150,10 @@ static void intel_quark_unregister_i2c_clk(struct pci_dev *pdev)
>  {
>  	struct intel_quark_mfd *quark_mfd = dev_get_drvdata(&pdev->dev);
>  
> -	if (!quark_mfd->i2c_clk || !quark_mfd->i2c_clk_lookup)
> +	clk_unregister(quark_mfd->i2c_clk);
> +	if (!quark_mfd->i2c_clk_lookup)
>  		return;
> -
>  	clkdev_drop(quark_mfd->i2c_clk_lookup);

It's probably not a great idea to unregister the clk before the
lookup is dropped. I suppose nothing too bad will happen though
because we handle this case in the framework and substitute dummy
ops in place of the real ones.

> -	clk_unregister(quark_mfd->i2c_clk);

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v1 1/2] mfd: intel_quark_i2c_gpio: remove clock tree on error path

[Andy Shevchenko]

On Fri, Feb 19, 2016 at 4:45 AM, Stephen Boyd <sboyd@codeaurora.org> wrote:
> On 02/17, Andy Shevchenko wrote:
>> diff --git a/drivers/mfd/intel_quark_i2c_gpio.c b/drivers/mfd/intel_quark_i2c_gpio.c
>> index bdc5e27..43d8066 100644
>> --- a/drivers/mfd/intel_quark_i2c_gpio.c
>> +++ b/drivers/mfd/intel_quark_i2c_gpio.c
>> @@ -150,11 +150,10 @@ static void intel_quark_unregister_i2c_clk(struct pci_dev *pdev)
>>  {
>>       struct intel_quark_mfd *quark_mfd = dev_get_drvdata(&pdev->dev);
>>
>> -     if (!quark_mfd->i2c_clk || !quark_mfd->i2c_clk_lookup)
>> +     clk_unregister(quark_mfd->i2c_clk);
>> +     if (!quark_mfd->i2c_clk_lookup)
>>               return;
>> -
>>       clkdev_drop(quark_mfd->i2c_clk_lookup);
>
> It's probably not a great idea to unregister the clk before the
> lookup is dropped. I suppose nothing too bad will happen though
> because we handle this case in the framework and substitute dummy
> ops in place of the real ones.

Thanks for pointing this out.

Okay, I will re-do this. I think the correct one is to add
clk_unregister() call to the _register_i2c_clk().



-- 
With Best Regards,
Andy Shevchenko