[PATCH v2 0/3] drm: fix i2c adapter device driver user counter

[PATCH v2 0/3] drm: fix i2c adapter device driver user counter

[Vladimir Zapolskiy]

of_find_i2c_adapter_by_node() call requires quite often missing
put_device(), and i2c_put_adapter() releases a device locked by
i2c_get_adapter() only.

Below is a common error reproduction scenario as a result of the
misusage described above (this is run on iMX6 platform with
HDMI and I2C bus drivers compiled as kernel modules for clearness):

    root@mx6q:~# lsmod | grep i2c
    i2c_imx                15348  0
    root@mx6q:~# lsmod | grep dw_hdmi_imx
    dw_hdmi_imx             3567  0
    dw_hdmi                15850  1 dw_hdmi_imx
    imxdrm                  8610  3 dw_hdmi_imx,imx_ipuv3_crtc,imx_ldb
    root@mx6q:~# rmmod dw_hdmi_imx
    root@mx6q:~# lsmod | grep i2c
    i2c_imx                15348  -1

                                 ^^^^^

    root@mx6q:~# rmmod i2c_imx
    rmmod: ERROR: Module i2c_imx is in use

To fix existing users of these interfaces use of_get_i2c_adapter_by_node()
interface, which is similar to i2c_get_adapter() in sense that an I2C bus
device driver found and locked by a user can be correctly unlocked by
i2c_put_adapter() call.

Changes from v1 to v2:
- none, this series is a straightforward bugfix, v1 was a blend of
  I2C core changes, bugfixes and improvements

The change is based on dri/drm-next.

Vladimir Zapolskiy (3):
  drm: dw_hdmi: use of_get_i2c_adapter_by_node interface
  drm: tilcdc: use of_get_i2c_adapter_by_node interface
  drm: tegra: use of_get_i2c_adapter_by_node interface

 drivers/gpu/drm/bridge/dw_hdmi.c       | 14 +++++++++-----
 drivers/gpu/drm/tegra/output.c         | 23 ++++++++++++-----------
 drivers/gpu/drm/tilcdc/tilcdc_tfp410.c |  6 ++----
 3 files changed, 23 insertions(+), 20 deletions(-)

-- 
2.5.0

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[PATCH v2 1/3] drm: dw_hdmi: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

This change is needed to properly lock I2C bus driver, which serves DDC.

The change fixes an overflow over zero of I2C bus driver user counter:

    root@mx6q:~# lsmod | grep i2c
    i2c_imx                15348  0
    root@mx6q:~# lsmod | grep dw_hdmi_imx
    dw_hdmi_imx             3567  0
    dw_hdmi                15850  1 dw_hdmi_imx
    imxdrm                  8610  3 dw_hdmi_imx,imx_ipuv3_crtc,imx_ldb
    root@mx6q:~# rmmod dw_hdmi_imx
    root@mx6q:~# lsmod | grep i2c
    i2c_imx                15348  -1

                                 ^^^^^

    root@mx6q:~# rmmod i2c_imx
    rmmod: ERROR: Module i2c_imx is in use

Note that prior to this change put_device() coupled with
of_find_i2c_adapter_by_node() was missing on error path of
dw_hdmi_bind(), added i2c_put_adapter() there along with the change.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Andy Yan <andy.yan@rock-chips.com>
---
Changes from v1 to v2:
- none

 drivers/gpu/drm/bridge/dw_hdmi.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c
index 0083d4e..c2d804f 100644
--- a/drivers/gpu/drm/bridge/dw_hdmi.c
+++ b/drivers/gpu/drm/bridge/dw_hdmi.c
@@ -1638,7 +1638,7 @@ int dw_hdmi_bind(struct device *dev, struct device *master,
 
 	ddc_node = of_parse_phandle(np, "ddc-i2c-bus", 0);
 	if (ddc_node) {
-		hdmi->ddc = of_find_i2c_adapter_by_node(ddc_node);
+		hdmi->ddc = of_get_i2c_adapter_by_node(ddc_node);
 		of_node_put(ddc_node);
 		if (!hdmi->ddc) {
 			dev_dbg(hdmi->dev, "failed to read ddc node\n");
@@ -1650,20 +1650,22 @@ int dw_hdmi_bind(struct device *dev, struct device *master,
 	}
 
 	hdmi->regs = devm_ioremap_resource(dev, iores);
-	if (IS_ERR(hdmi->regs))
-		return PTR_ERR(hdmi->regs);
+	if (IS_ERR(hdmi->regs)) {
+		ret = PTR_ERR(hdmi->regs);
+		goto err_res;
+	}
 
 	hdmi->isfr_clk = devm_clk_get(hdmi->dev, "isfr");
 	if (IS_ERR(hdmi->isfr_clk)) {
 		ret = PTR_ERR(hdmi->isfr_clk);
 		dev_err(hdmi->dev, "Unable to get HDMI isfr clk: %d\n", ret);
-		return ret;
+		goto err_res;
 	}
 
 	ret = clk_prepare_enable(hdmi->isfr_clk);
 	if (ret) {
 		dev_err(hdmi->dev, "Cannot enable HDMI isfr clock: %d\n", ret);
-		return ret;
+		goto err_res;
 	}
 
 	hdmi->iahb_clk = devm_clk_get(hdmi->dev, "iahb");
@@ -1729,6 +1731,8 @@ err_iahb:
 	clk_disable_unprepare(hdmi->iahb_clk);
 err_isfr:
 	clk_disable_unprepare(hdmi->isfr_clk);
+err_res:
+	i2c_put_adapter(hdmi->ddc);
 
 	return ret;
 }
-- 
2.5.0

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[PATCH v2 2/3] drm: tilcdc: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

This change is needed to properly lock I2C bus driver, which serves DDC.

Prior to this change i2c_put_adapter() is misused, which may lead
to an overflow over zero of I2C bus driver user counter.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
---
Changes from v1 to v2:
- none

 drivers/gpu/drm/tilcdc/tilcdc_tfp410.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c b/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c
index 354c47c..4dc78c7 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c
@@ -348,15 +348,13 @@ static int tfp410_probe(struct platform_device *pdev)
 		goto fail;
 	}
 
-	tfp410_mod->i2c = of_find_i2c_adapter_by_node(i2c_node);
+	tfp410_mod->i2c = of_get_i2c_adapter_by_node(i2c_node);
+	of_node_put(i2c_node);
 	if (!tfp410_mod->i2c) {
 		dev_err(&pdev->dev, "could not get i2c\n");
-		of_node_put(i2c_node);
 		goto fail;
 	}
 
-	of_node_put(i2c_node);
-
 	tfp410_mod->gpio = of_get_named_gpio_flags(node, "powerdn-gpio",
 			0, NULL);
 	if (IS_ERR_VALUE(tfp410_mod->gpio)) {
-- 
2.5.0

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[PATCH v2 3/3] drm: tegra: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

This change is needed to properly lock I2C bus driver, which serves DDC.

On release of_get_i2c_adapter_by_node() requires i2c_put_adapter() call.

Note, that prior to the change put_device() coupled with
of_find_i2c_adapter_by_node() was missing on error path of
tegra_output_probe().

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Terje Bergström <tbergstrom@nvidia.com>
---
Changes from v1 to v2:
- converted two of_node_put(ddc) calls into one

 drivers/gpu/drm/tegra/output.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/tegra/output.c b/drivers/gpu/drm/tegra/output.c
index 46664b6..9f3cec5 100644
--- a/drivers/gpu/drm/tegra/output.c
+++ b/drivers/gpu/drm/tegra/output.c
@@ -120,14 +120,12 @@ int tegra_output_probe(struct tegra_output *output)
 
 	ddc = of_parse_phandle(output->of_node, "nvidia,ddc-i2c-bus", 0);
 	if (ddc) {
-		output->ddc = of_find_i2c_adapter_by_node(ddc);
+		output->ddc = of_get_i2c_adapter_by_node(ddc);
+		of_node_put(ddc);
 		if (!output->ddc) {
 			err = -EPROBE_DEFER;
-			of_node_put(ddc);
 			return err;
 		}
-
-		of_node_put(ddc);
 	}
 
 	output->hpd_gpio = of_get_named_gpio_flags(output->of_node,
@@ -140,14 +138,13 @@ int tegra_output_probe(struct tegra_output *output)
 				       "HDMI hotplug detect");
 		if (err < 0) {
 			dev_err(output->dev, "gpio_request_one(): %d\n", err);
-			return err;
+			goto i2c_release;
 		}
 
 		err = gpio_to_irq(output->hpd_gpio);
 		if (err < 0) {
 			dev_err(output->dev, "gpio_to_irq(): %d\n", err);
-			gpio_free(output->hpd_gpio);
-			return err;
+			goto gpio_release;
 		}
 
 		output->hpd_irq = err;
@@ -160,8 +157,7 @@ int tegra_output_probe(struct tegra_output *output)
 		if (err < 0) {
 			dev_err(output->dev, "failed to request IRQ#%u: %d\n",
 				output->hpd_irq, err);
-			gpio_free(output->hpd_gpio);
-			return err;
+			goto gpio_release;
 		}
 
 		output->connector.polled = DRM_CONNECTOR_POLL_HPD;
@@ -175,6 +171,12 @@ int tegra_output_probe(struct tegra_output *output)
 	}
 
 	return 0;
+
+ gpio_release:
+	gpio_free(output->hpd_gpio);
+ i2c_release:
+	i2c_put_adapter(output->ddc);
+	return err;
 }
 
 void tegra_output_remove(struct tegra_output *output)
@@ -184,8 +186,7 @@ void tegra_output_remove(struct tegra_output *output)
 		gpio_free(output->hpd_gpio);
 	}
 
-	if (output->ddc)
-		put_device(&output->ddc->dev);
+	i2c_put_adapter(output->ddc);
 }
 
 int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
-- 
2.5.0

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Re: [PATCH v2 1/3] drm: dw_hdmi: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

David, Russel,

ping.

On 23.09.2015 00:48, Vladimir Zapolskiy wrote:
> This change is needed to properly lock I2C bus driver, which serves DDC.
> 
> The change fixes an overflow over zero of I2C bus driver user counter:
> 
>     root@mx6q:~# lsmod | grep i2c
>     i2c_imx                15348  0
>     root@mx6q:~# lsmod | grep dw_hdmi_imx
>     dw_hdmi_imx             3567  0
>     dw_hdmi                15850  1 dw_hdmi_imx
>     imxdrm                  8610  3 dw_hdmi_imx,imx_ipuv3_crtc,imx_ldb
>     root@mx6q:~# rmmod dw_hdmi_imx
>     root@mx6q:~# lsmod | grep i2c
>     i2c_imx                15348  -1
> 
>                                  ^^^^^
> 
>     root@mx6q:~# rmmod i2c_imx
>     rmmod: ERROR: Module i2c_imx is in use
> 
> Note that prior to this change put_device() coupled with
> of_find_i2c_adapter_by_node() was missing on error path of
> dw_hdmi_bind(), added i2c_put_adapter() there along with the change.
> 
> Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
> Cc: Russell King <rmk+kernel@arm.linux.org.uk>
> Cc: Philipp Zabel <p.zabel@pengutronix.de>
> Cc: Andy Yan <andy.yan@rock-chips.com>

--
With best wishes,
Vladimir

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Re: [PATCH v2 0/3] drm: fix i2c adapter device driver user counter

[Vladimir Zapolskiy]

David, Russell,

ping.

On 23.09.2015 00:46, Vladimir Zapolskiy wrote:
> of_find_i2c_adapter_by_node() call requires quite often missing
> put_device(), and i2c_put_adapter() releases a device locked by
> i2c_get_adapter() only.
> 
> Below is a common error reproduction scenario as a result of the
> misusage described above (this is run on iMX6 platform with
> HDMI and I2C bus drivers compiled as kernel modules for clearness):
> 
>     root@mx6q:~# lsmod | grep i2c
>     i2c_imx                15348  0
>     root@mx6q:~# lsmod | grep dw_hdmi_imx
>     dw_hdmi_imx             3567  0
>     dw_hdmi                15850  1 dw_hdmi_imx
>     imxdrm                  8610  3 dw_hdmi_imx,imx_ipuv3_crtc,imx_ldb
>     root@mx6q:~# rmmod dw_hdmi_imx
>     root@mx6q:~# lsmod | grep i2c
>     i2c_imx                15348  -1
> 
>                                  ^^^^^
> 
>     root@mx6q:~# rmmod i2c_imx
>     rmmod: ERROR: Module i2c_imx is in use
> 
> To fix existing users of these interfaces use of_get_i2c_adapter_by_node()
> interface, which is similar to i2c_get_adapter() in sense that an I2C bus
> device driver found and locked by a user can be correctly unlocked by
> i2c_put_adapter() call.
> 
> Changes from v1 to v2:
> - none, this series is a straightforward bugfix, v1 was a blend of
>   I2C core changes, bugfixes and improvements
> 
> The change is based on dri/drm-next.
> 
> Vladimir Zapolskiy (3):
>   drm: dw_hdmi: use of_get_i2c_adapter_by_node interface
>   drm: tilcdc: use of_get_i2c_adapter_by_node interface
>   drm: tegra: use of_get_i2c_adapter_by_node interface
> 
>  drivers/gpu/drm/bridge/dw_hdmi.c       | 14 +++++++++-----
>  drivers/gpu/drm/tegra/output.c         | 23 ++++++++++++-----------
>  drivers/gpu/drm/tilcdc/tilcdc_tfp410.c |  6 ++----
>  3 files changed, 23 insertions(+), 20 deletions(-)
> 

--
With best wishes,
Vladimir
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Re: [PATCH v2 0/3] drm: fix i2c adapter device driver user counter

[Vladimir Zapolskiy]

David, Russell,

ping.

On 12.10.2015 16:15, Vladimir Zapolskiy wrote:
> David, Russell,
> 
> ping.
> 
> On 23.09.2015 00:46, Vladimir Zapolskiy wrote:
>> of_find_i2c_adapter_by_node() call requires quite often missing
>> put_device(), and i2c_put_adapter() releases a device locked by
>> i2c_get_adapter() only.
>>
>> Below is a common error reproduction scenario as a result of the
>> misusage described above (this is run on iMX6 platform with
>> HDMI and I2C bus drivers compiled as kernel modules for clearness):
>>
>>     root@mx6q:~# lsmod | grep i2c
>>     i2c_imx                15348  0
>>     root@mx6q:~# lsmod | grep dw_hdmi_imx
>>     dw_hdmi_imx             3567  0
>>     dw_hdmi                15850  1 dw_hdmi_imx
>>     imxdrm                  8610  3 dw_hdmi_imx,imx_ipuv3_crtc,imx_ldb
>>     root@mx6q:~# rmmod dw_hdmi_imx
>>     root@mx6q:~# lsmod | grep i2c
>>     i2c_imx                15348  -1
>>
>>                                  ^^^^^
>>
>>     root@mx6q:~# rmmod i2c_imx
>>     rmmod: ERROR: Module i2c_imx is in use
>>
>> To fix existing users of these interfaces use of_get_i2c_adapter_by_node()
>> interface, which is similar to i2c_get_adapter() in sense that an I2C bus
>> device driver found and locked by a user can be correctly unlocked by
>> i2c_put_adapter() call.
>>
>> Changes from v1 to v2:
>> - none, this series is a straightforward bugfix, v1 was a blend of
>>   I2C core changes, bugfixes and improvements
>>
>> The change is based on dri/drm-next.
>>
>> Vladimir Zapolskiy (3):
>>   drm: dw_hdmi: use of_get_i2c_adapter_by_node interface
>>   drm: tilcdc: use of_get_i2c_adapter_by_node interface
>>   drm: tegra: use of_get_i2c_adapter_by_node interface
>>
>>  drivers/gpu/drm/bridge/dw_hdmi.c       | 14 +++++++++-----
>>  drivers/gpu/drm/tegra/output.c         | 23 ++++++++++++-----------
>>  drivers/gpu/drm/tilcdc/tilcdc_tfp410.c |  6 ++----
>>  3 files changed, 23 insertions(+), 20 deletions(-)
>>
> 

--
With best wishes,
Vladimir

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Re: [PATCH v2 0/3] drm: fix i2c adapter device driver user counter

[Vladimir Zapolskiy]

David, Russell,

ping. No response for more than 2 months.

On 02.11.2015 17:10, Vladimir Zapolskiy wrote:
> David, Russell,
> 
> ping.
> 
> On 12.10.2015 16:15, Vladimir Zapolskiy wrote:
>> David, Russell,
>>
>> ping.
>>
>> On 23.09.2015 00:46, Vladimir Zapolskiy wrote:
>>> of_find_i2c_adapter_by_node() call requires quite often missing
>>> put_device(), and i2c_put_adapter() releases a device locked by
>>> i2c_get_adapter() only.
>>>
>>> Below is a common error reproduction scenario as a result of the
>>> misusage described above (this is run on iMX6 platform with
>>> HDMI and I2C bus drivers compiled as kernel modules for clearness):
>>>
>>>     root@mx6q:~# lsmod | grep i2c
>>>     i2c_imx                15348  0
>>>     root@mx6q:~# lsmod | grep dw_hdmi_imx
>>>     dw_hdmi_imx             3567  0
>>>     dw_hdmi                15850  1 dw_hdmi_imx
>>>     imxdrm                  8610  3 dw_hdmi_imx,imx_ipuv3_crtc,imx_ldb
>>>     root@mx6q:~# rmmod dw_hdmi_imx
>>>     root@mx6q:~# lsmod | grep i2c
>>>     i2c_imx                15348  -1
>>>
>>>                                  ^^^^^
>>>
>>>     root@mx6q:~# rmmod i2c_imx
>>>     rmmod: ERROR: Module i2c_imx is in use
>>>
>>> To fix existing users of these interfaces use of_get_i2c_adapter_by_node()
>>> interface, which is similar to i2c_get_adapter() in sense that an I2C bus
>>> device driver found and locked by a user can be correctly unlocked by
>>> i2c_put_adapter() call.
>>>
>>> Changes from v1 to v2:
>>> - none, this series is a straightforward bugfix, v1 was a blend of
>>>   I2C core changes, bugfixes and improvements
>>>
>>> The change is based on dri/drm-next.
>>>
>>> Vladimir Zapolskiy (3):
>>>   drm: dw_hdmi: use of_get_i2c_adapter_by_node interface
>>>   drm: tilcdc: use of_get_i2c_adapter_by_node interface
>>>   drm: tegra: use of_get_i2c_adapter_by_node interface
>>>
>>>  drivers/gpu/drm/bridge/dw_hdmi.c       | 14 +++++++++-----
>>>  drivers/gpu/drm/tegra/output.c         | 23 ++++++++++++-----------
>>>  drivers/gpu/drm/tilcdc/tilcdc_tfp410.c |  6 ++----
>>>  3 files changed, 23 insertions(+), 20 deletions(-)
>>>
>>
> 

--
With best wishes,
Vladimir

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