[PATCH] i2c-piix4: Fully initialize SB800 before it is registered

[PATCH] i2c-piix4: Fully initialize SB800 before it is registered

[Jean Delvare]

This closes a race window where I2C device drivers attempt to access
I2C buses which aren't fully initialized yet.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Christian Fetzer <fetzer.ch@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
---
 drivers/i2c/busses/i2c-piix4.c |   19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

--- linux-4.5-rc0.orig/drivers/i2c/busses/i2c-piix4.c	2016-01-22 14:06:31.336751852 +0100
+++ linux-4.5-rc0/drivers/i2c/busses/i2c-piix4.c	2016-01-25 12:08:07.812116538 +0100
@@ -627,6 +627,7 @@ static struct i2c_adapter *piix4_main_ad
 static struct i2c_adapter *piix4_aux_adapter;
 
 static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
+			     bool sb800_main, unsigned short port,
 			     const char *name, struct i2c_adapter **padap)
 {
 	struct i2c_adapter *adap;
@@ -641,7 +642,8 @@ static int piix4_add_adapter(struct pci_
 
 	adap->owner = THIS_MODULE;
 	adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
-	adap->algo = &smbus_algorithm;
+	adap->algo = sb800_main ? &piix4_smbus_algorithm_sb800
+				: &smbus_algorithm;
 
 	adapdata = kzalloc(sizeof(*adapdata), GFP_KERNEL);
 	if (adapdata == NULL) {
@@ -651,6 +653,8 @@ static int piix4_add_adapter(struct pci_
 	}
 
 	adapdata->smba = smba;
+	adapdata->sb800_main = sb800_main;
+	adapdata->port = port;
 
 	/* set up the sysfs linkage to our parent device */
 	adap->dev.parent = &dev->dev;
@@ -680,17 +684,11 @@ static int piix4_add_adapters_sb800(stru
 	int retval;
 
 	for (port = 0; port < PIIX4_MAX_ADAPTERS; port++) {
-		retval = piix4_add_adapter(dev, smba,
+		retval = piix4_add_adapter(dev, smba, true, port,
 					   piix4_main_port_names_sb800[port],
 					   &piix4_main_adapters[port]);
 		if (retval < 0)
 			goto error;
-
-		piix4_main_adapters[port]->algo = &piix4_smbus_algorithm_sb800;
-
-		adapdata = i2c_get_adapdata(piix4_main_adapters[port]);
-		adapdata->sb800_main = true;
-		adapdata->port = port;
 	}
 
 	return retval;
@@ -748,7 +746,7 @@ static int piix4_probe(struct pci_dev *d
 			return retval;
 
 		/* Try to register main SMBus adapter, give up if we can't */
-		retval = piix4_add_adapter(dev, retval, "main",
+		retval = piix4_add_adapter(dev, retval, false, 0, "main",
 					   &piix4_main_adapters[0]);
 		if (retval < 0)
 			return retval;
@@ -775,7 +773,8 @@ static int piix4_probe(struct pci_dev *d
 	if (retval > 0) {
 		/* Try to add the aux adapter if it exists,
 		 * piix4_add_adapter will clean up if this fails */
-		piix4_add_adapter(dev, retval, piix4_aux_port_name_sb800,
+		piix4_add_adapter(dev, retval, false, 0,
+				  piix4_aux_port_name_sb800,
 				  &piix4_aux_adapter);
 	}
 


-- 
Jean Delvare
SUSE L3 Support

Re: [PATCH] i2c-piix4: Fully initialize SB800 before it is registered

[Christian Fetzer]

Hi Jean,

> Am 25.01.2016 um 12:17 schrieb Jean Delvare <jdelvare@suse.de>:
> 
> This closes a race window where I2C device drivers attempt to access
> I2C buses which aren't fully initialized yet.
> 

I’m not sure if it’s common to offer tags as first-time contributor, but feel free to add
Tested-by: Christian Fetzer <fetzer.ch@gmail.com>

> Signed-off-by: Jean Delvare <jdelvare@suse.de>
> Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
> Cc: Christian Fetzer <fetzer.ch@gmail.com>
> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Cc: Wolfram Sang <wsa@the-dreams.de>
> ---
> drivers/i2c/busses/i2c-piix4.c |   19 +++++++++----------
> 1 file changed, 9 insertions(+), 10 deletions(-)
> 
> --- linux-4.5-rc0.orig/drivers/i2c/busses/i2c-piix4.c	2016-01-22 14:06:31.336751852 +0100
> +++ linux-4.5-rc0/drivers/i2c/busses/i2c-piix4.c	2016-01-25 12:08:07.812116538 +0100
> @@ -627,6 +627,7 @@ static struct i2c_adapter *piix4_main_ad
> static struct i2c_adapter *piix4_aux_adapter;
> 
> static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
> +			     bool sb800_main, unsigned short port,
> 			     const char *name, struct i2c_adapter **padap)
> {
> 	struct i2c_adapter *adap;
> @@ -641,7 +642,8 @@ static int piix4_add_adapter(struct pci_
> 
> 	adap->owner = THIS_MODULE;
> 	adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
> -	adap->algo = &smbus_algorithm;
> +	adap->algo = sb800_main ? &piix4_smbus_algorithm_sb800
> +				: &smbus_algorithm;
> 
> 	adapdata = kzalloc(sizeof(*adapdata), GFP_KERNEL);
> 	if (adapdata == NULL) {
> @@ -651,6 +653,8 @@ static int piix4_add_adapter(struct pci_
> 	}
> 
> 	adapdata->smba = smba;
> +	adapdata->sb800_main = sb800_main;
> +	adapdata->port = port;
> 
> 	/* set up the sysfs linkage to our parent device */
> 	adap->dev.parent = &dev->dev;
> @@ -680,17 +684,11 @@ static int piix4_add_adapters_sb800(stru
> 	int retval;
> 
> 	for (port = 0; port < PIIX4_MAX_ADAPTERS; port++) {
> -		retval = piix4_add_adapter(dev, smba,
> +		retval = piix4_add_adapter(dev, smba, true, port,
> 					   piix4_main_port_names_sb800[port],
> 					   &piix4_main_adapters[port]);
> 		if (retval < 0)
> 			goto error;
> -
> -		piix4_main_adapters[port]->algo = &piix4_smbus_algorithm_sb800;
> -
> -		adapdata = i2c_get_adapdata(piix4_main_adapters[port]);
> -		adapdata->sb800_main = true;
> -		adapdata->port = port;
> 	}
> 
> 	return retval;
> @@ -748,7 +746,7 @@ static int piix4_probe(struct pci_dev *d
> 			return retval;
> 
> 		/* Try to register main SMBus adapter, give up if we can't */
> -		retval = piix4_add_adapter(dev, retval, "main",
> +		retval = piix4_add_adapter(dev, retval, false, 0, "main",
> 					   &piix4_main_adapters[0]);
> 		if (retval < 0)
> 			return retval;
> @@ -775,7 +773,8 @@ static int piix4_probe(struct pci_dev *d
> 	if (retval > 0) {
> 		/* Try to add the aux adapter if it exists,
> 		 * piix4_add_adapter will clean up if this fails */
> -		piix4_add_adapter(dev, retval, piix4_aux_port_name_sb800,
> +		piix4_add_adapter(dev, retval, false, 0,
> +				  piix4_aux_port_name_sb800,
> 				  &piix4_aux_adapter);
> 	}
> 
> 
> 
> -- 
> Jean Delvare
> SUSE L3 Support

Re: [PATCH] i2c-piix4: Fully initialize SB800 before it is registered

[Wolfram Sang]

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> I’m not sure if it’s common to offer tags as first-time contributor, but feel free to add

Sure, it is! It is extremly helpful for me as a maintainer if someone
who reported a problem confirms that the problem is gone now.

> Tested-by: Christian Fetzer <fetzer.ch@gmail.com>

Thanks a lot!

   Wolfram


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Re: [PATCH] i2c-piix4: Fully initialize SB800 before it is registered

[Wolfram Sang]

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On Mon, Jan 25, 2016 at 12:17:07PM +0100, Jean Delvare wrote:
> This closes a race window where I2C device drivers attempt to access
> I2C buses which aren't fully initialized yet.
> 
> Signed-off-by: Jean Delvare <jdelvare@suse.de>
> Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
> Cc: Christian Fetzer <fetzer.ch@gmail.com>
> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Cc: Wolfram Sang <wsa@the-dreams.de>

Applied to for-current, thanks!


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