diff mbox series

[1/4] rpmsg: ctrl: Introduce RPMSG_CREATE_DEV_IOCTL

Message ID 20210604091406.15901-2-arnaud.pouliquen@foss.st.com (mailing list archive)
State Superseded
Headers show
Series rpmsg: ctrl: Add ability to instantiate rpmsg device locally | expand

Commit Message

Arnaud Pouliquen June 4, 2021, 9:14 a.m. UTC
Implement the RPMSG_CREATE_DEV_IOCTL to allow the user application to
initiate a communication through a new rpmsg channel.
This Ioctl can be used to instantiate a local rpmsg device.
Depending on the back-end implementation, the associated rpmsg driver is
probed and a NS announcement can be sent to the remote processor.

Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
---
 drivers/rpmsg/rpmsg_ctrl.c | 30 ++++++++++++++++++++++++++----
 include/uapi/linux/rpmsg.h |  5 +++++
 2 files changed, 31 insertions(+), 4 deletions(-)

Comments

Mathieu Poirier June 15, 2021, 5:53 p.m. UTC | #1
On Fri, Jun 04, 2021 at 11:14:03AM +0200, Arnaud Pouliquen wrote:
> Implement the RPMSG_CREATE_DEV_IOCTL to allow the user application to
> initiate a communication through a new rpmsg channel.
> This Ioctl can be used to instantiate a local rpmsg device.
> Depending on the back-end implementation, the associated rpmsg driver is
> probed and a NS announcement can be sent to the remote processor.
> 
> Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
>  drivers/rpmsg/rpmsg_ctrl.c | 30 ++++++++++++++++++++++++++----
>  include/uapi/linux/rpmsg.h |  5 +++++
>  2 files changed, 31 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
> index eeb1708548c1..4aa962df3661 100644
> --- a/drivers/rpmsg/rpmsg_ctrl.c
> +++ b/drivers/rpmsg/rpmsg_ctrl.c
> @@ -23,6 +23,7 @@
>  #include <uapi/linux/rpmsg.h>
>  
>  #include "rpmsg_char.h"
> +#include "rpmsg_internal.h"
>  
>  static dev_t rpmsg_major;
>  
> @@ -37,11 +38,13 @@ static DEFINE_IDA(rpmsg_minor_ida);
>   * @rpdev:	underlaying rpmsg device
>   * @cdev:	cdev for the ctrl device
>   * @dev:	device for the ctrl device
> + * @ctrl_lock:	serialize the ioctrls.
>   */
>  struct rpmsg_ctrldev {
>  	struct rpmsg_device *rpdev;
>  	struct cdev cdev;
>  	struct device dev;
> +	struct mutex ctrl_lock;
>  };
>  
>  static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
> @@ -70,9 +73,8 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
>  	void __user *argp = (void __user *)arg;
>  	struct rpmsg_endpoint_info eptinfo;
>  	struct rpmsg_channel_info chinfo;
> -
> -	if (cmd != RPMSG_CREATE_EPT_IOCTL)
> -		return -EINVAL;
> +	struct rpmsg_device *rpdev;
> +	int ret = 0;
>  
>  	if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
>  		return -EFAULT;
> @@ -82,7 +84,26 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
>  	chinfo.src = eptinfo.src;
>  	chinfo.dst = eptinfo.dst;
>  
> -	return rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
> +	mutex_lock(&ctrldev->ctrl_lock);

Do we need a lock here?  I thought the character device layer would guarantee
accesses on a file handler would be atomic...  Am I wrong?

> +	switch (cmd) {
> +	case RPMSG_CREATE_EPT_IOCTL:
> +		ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
> +		break;
> +
> +	case RPMSG_CREATE_DEV_IOCTL:
> +		rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo);
> +		if (!rpdev) {
> +			dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name);
> +			ret = -ENXIO;
> +		}
> +		break;
> +
> +	default:
> +		ret = -EINVAL;
> +	}
> +	mutex_unlock(&ctrldev->ctrl_lock);
> +
> +	return ret;
>  };
>  
>  static const struct file_operations rpmsg_ctrldev_fops = {
> @@ -119,6 +140,7 @@ static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev)
>  	device_initialize(dev);
>  	dev->parent = &rpdev->dev;
>  
> +	mutex_init(&ctrldev->ctrl_lock);
>  	cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
>  	ctrldev->cdev.owner = THIS_MODULE;
>  
> diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h
> index f5ca8740f3fb..f9d5a74e7801 100644
> --- a/include/uapi/linux/rpmsg.h
> +++ b/include/uapi/linux/rpmsg.h
> @@ -33,4 +33,9 @@ struct rpmsg_endpoint_info {
>   */
>  #define RPMSG_DESTROY_EPT_IOCTL	_IO(0xb5, 0x2)
>  
> +/**
> + * Instantiate a rpmsg service device.
> + */
> +#define RPMSG_CREATE_DEV_IOCTL	_IOW(0xb5, 0x3, struct rpmsg_endpoint_info)
> +
>  #endif
> -- 
> 2.17.1
>
Arnaud Pouliquen June 16, 2021, 8:12 a.m. UTC | #2
Hello Mathieu,

On 6/15/21 7:53 PM, Mathieu Poirier wrote:
> On Fri, Jun 04, 2021 at 11:14:03AM +0200, Arnaud Pouliquen wrote:
>> Implement the RPMSG_CREATE_DEV_IOCTL to allow the user application to
>> initiate a communication through a new rpmsg channel.
>> This Ioctl can be used to instantiate a local rpmsg device.
>> Depending on the back-end implementation, the associated rpmsg driver is
>> probed and a NS announcement can be sent to the remote processor.
>>
>> Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>> ---
>>  drivers/rpmsg/rpmsg_ctrl.c | 30 ++++++++++++++++++++++++++----
>>  include/uapi/linux/rpmsg.h |  5 +++++
>>  2 files changed, 31 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
>> index eeb1708548c1..4aa962df3661 100644
>> --- a/drivers/rpmsg/rpmsg_ctrl.c
>> +++ b/drivers/rpmsg/rpmsg_ctrl.c
>> @@ -23,6 +23,7 @@
>>  #include <uapi/linux/rpmsg.h>
>>  
>>  #include "rpmsg_char.h"
>> +#include "rpmsg_internal.h"
>>  
>>  static dev_t rpmsg_major;
>>  
>> @@ -37,11 +38,13 @@ static DEFINE_IDA(rpmsg_minor_ida);
>>   * @rpdev:	underlaying rpmsg device
>>   * @cdev:	cdev for the ctrl device
>>   * @dev:	device for the ctrl device
>> + * @ctrl_lock:	serialize the ioctrls.
>>   */
>>  struct rpmsg_ctrldev {
>>  	struct rpmsg_device *rpdev;
>>  	struct cdev cdev;
>>  	struct device dev;
>> +	struct mutex ctrl_lock;
>>  };
>>  
>>  static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
>> @@ -70,9 +73,8 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
>>  	void __user *argp = (void __user *)arg;
>>  	struct rpmsg_endpoint_info eptinfo;
>>  	struct rpmsg_channel_info chinfo;
>> -
>> -	if (cmd != RPMSG_CREATE_EPT_IOCTL)
>> -		return -EINVAL;
>> +	struct rpmsg_device *rpdev;
>> +	int ret = 0;
>>  
>>  	if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
>>  		return -EFAULT;
>> @@ -82,7 +84,26 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
>>  	chinfo.src = eptinfo.src;
>>  	chinfo.dst = eptinfo.dst;
>>  
>> -	return rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
>> +	mutex_lock(&ctrldev->ctrl_lock);
> 
> Do we need a lock here?  I thought the character device layer would guarantee
> accesses on a file handler would be atomic...  Am I wrong?
> 

It is a good point! from my understanding, using "unlocked_ioctl" ops, the
driver has to handle is own atomic protection.
I will try to hack the code to verify this.

Thanks,
Arnaud

>> +	switch (cmd) {
>> +	case RPMSG_CREATE_EPT_IOCTL:
>> +		ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
>> +		break;
>> +
>> +	case RPMSG_CREATE_DEV_IOCTL:
>> +		rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo);
>> +		if (!rpdev) {
>> +			dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name);
>> +			ret = -ENXIO;
>> +		}
>> +		break;
>> +
>> +	default:
>> +		ret = -EINVAL;
>> +	}
>> +	mutex_unlock(&ctrldev->ctrl_lock);
>> +
>> +	return ret;
>>  };
>>  
>>  static const struct file_operations rpmsg_ctrldev_fops = {
>> @@ -119,6 +140,7 @@ static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev)
>>  	device_initialize(dev);
>>  	dev->parent = &rpdev->dev;
>>  
>> +	mutex_init(&ctrldev->ctrl_lock);
>>  	cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
>>  	ctrldev->cdev.owner = THIS_MODULE;
>>  
>> diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h
>> index f5ca8740f3fb..f9d5a74e7801 100644
>> --- a/include/uapi/linux/rpmsg.h
>> +++ b/include/uapi/linux/rpmsg.h
>> @@ -33,4 +33,9 @@ struct rpmsg_endpoint_info {
>>   */
>>  #define RPMSG_DESTROY_EPT_IOCTL	_IO(0xb5, 0x2)
>>  
>> +/**
>> + * Instantiate a rpmsg service device.
>> + */
>> +#define RPMSG_CREATE_DEV_IOCTL	_IOW(0xb5, 0x3, struct rpmsg_endpoint_info)
>> +
>>  #endif
>> -- 
>> 2.17.1
>>
Arnaud Pouliquen June 21, 2021, 9:35 a.m. UTC | #3
On 6/16/21 10:12 AM, Arnaud POULIQUEN wrote:
> Hello Mathieu,
> 
> On 6/15/21 7:53 PM, Mathieu Poirier wrote:
>> On Fri, Jun 04, 2021 at 11:14:03AM +0200, Arnaud Pouliquen wrote:
>>> Implement the RPMSG_CREATE_DEV_IOCTL to allow the user application to
>>> initiate a communication through a new rpmsg channel.
>>> This Ioctl can be used to instantiate a local rpmsg device.
>>> Depending on the back-end implementation, the associated rpmsg driver is
>>> probed and a NS announcement can be sent to the remote processor.
>>>
>>> Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
>>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>>> ---
>>>  drivers/rpmsg/rpmsg_ctrl.c | 30 ++++++++++++++++++++++++++----
>>>  include/uapi/linux/rpmsg.h |  5 +++++
>>>  2 files changed, 31 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
>>> index eeb1708548c1..4aa962df3661 100644
>>> --- a/drivers/rpmsg/rpmsg_ctrl.c
>>> +++ b/drivers/rpmsg/rpmsg_ctrl.c
>>> @@ -23,6 +23,7 @@
>>>  #include <uapi/linux/rpmsg.h>
>>>  
>>>  #include "rpmsg_char.h"
>>> +#include "rpmsg_internal.h"
>>>  
>>>  static dev_t rpmsg_major;
>>>  
>>> @@ -37,11 +38,13 @@ static DEFINE_IDA(rpmsg_minor_ida);
>>>   * @rpdev:	underlaying rpmsg device
>>>   * @cdev:	cdev for the ctrl device
>>>   * @dev:	device for the ctrl device
>>> + * @ctrl_lock:	serialize the ioctrls.
>>>   */
>>>  struct rpmsg_ctrldev {
>>>  	struct rpmsg_device *rpdev;
>>>  	struct cdev cdev;
>>>  	struct device dev;
>>> +	struct mutex ctrl_lock;
>>>  };
>>>  
>>>  static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
>>> @@ -70,9 +73,8 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
>>>  	void __user *argp = (void __user *)arg;
>>>  	struct rpmsg_endpoint_info eptinfo;
>>>  	struct rpmsg_channel_info chinfo;
>>> -
>>> -	if (cmd != RPMSG_CREATE_EPT_IOCTL)
>>> -		return -EINVAL;
>>> +	struct rpmsg_device *rpdev;
>>> +	int ret = 0;
>>>  
>>>  	if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
>>>  		return -EFAULT;
>>> @@ -82,7 +84,26 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
>>>  	chinfo.src = eptinfo.src;
>>>  	chinfo.dst = eptinfo.dst;
>>>  
>>> -	return rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
>>> +	mutex_lock(&ctrldev->ctrl_lock);
>>
>> Do we need a lock here?  I thought the character device layer would guarantee
>> accesses on a file handler would be atomic...  Am I wrong?
>>
> 
> It is a good point! from my understanding, using "unlocked_ioctl" ops, the
> driver has to handle is own atomic protection.
> I will try to hack the code to verify this.

I confirm without lock there is no atomic access, re-entrance is possible in
rpmsg_ctrldev_ioctl. Keeping lock to serialize the controls seems safer to me to
avoid race condition.

Regards
Arnaud

> 
> Thanks,
> Arnaud
> 
>>> +	switch (cmd) {
>>> +	case RPMSG_CREATE_EPT_IOCTL:
>>> +		ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
>>> +		break;
>>> +
>>> +	case RPMSG_CREATE_DEV_IOCTL:
>>> +		rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo);
>>> +		if (!rpdev) {
>>> +			dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name);
>>> +			ret = -ENXIO;
>>> +		}
>>> +		break;
>>> +
>>> +	default:
>>> +		ret = -EINVAL;
>>> +	}
>>> +	mutex_unlock(&ctrldev->ctrl_lock);
>>> +
>>> +	return ret;
>>>  };
>>>  
>>>  static const struct file_operations rpmsg_ctrldev_fops = {
>>> @@ -119,6 +140,7 @@ static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev)
>>>  	device_initialize(dev);
>>>  	dev->parent = &rpdev->dev;
>>>  
>>> +	mutex_init(&ctrldev->ctrl_lock);
>>>  	cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
>>>  	ctrldev->cdev.owner = THIS_MODULE;
>>>  
>>> diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h
>>> index f5ca8740f3fb..f9d5a74e7801 100644
>>> --- a/include/uapi/linux/rpmsg.h
>>> +++ b/include/uapi/linux/rpmsg.h
>>> @@ -33,4 +33,9 @@ struct rpmsg_endpoint_info {
>>>   */
>>>  #define RPMSG_DESTROY_EPT_IOCTL	_IO(0xb5, 0x2)
>>>  
>>> +/**
>>> + * Instantiate a rpmsg service device.
>>> + */
>>> +#define RPMSG_CREATE_DEV_IOCTL	_IOW(0xb5, 0x3, struct rpmsg_endpoint_info)
>>> +
>>>  #endif
>>> -- 
>>> 2.17.1
>>>
diff mbox series

Patch

diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c
index eeb1708548c1..4aa962df3661 100644
--- a/drivers/rpmsg/rpmsg_ctrl.c
+++ b/drivers/rpmsg/rpmsg_ctrl.c
@@ -23,6 +23,7 @@ 
 #include <uapi/linux/rpmsg.h>
 
 #include "rpmsg_char.h"
+#include "rpmsg_internal.h"
 
 static dev_t rpmsg_major;
 
@@ -37,11 +38,13 @@  static DEFINE_IDA(rpmsg_minor_ida);
  * @rpdev:	underlaying rpmsg device
  * @cdev:	cdev for the ctrl device
  * @dev:	device for the ctrl device
+ * @ctrl_lock:	serialize the ioctrls.
  */
 struct rpmsg_ctrldev {
 	struct rpmsg_device *rpdev;
 	struct cdev cdev;
 	struct device dev;
+	struct mutex ctrl_lock;
 };
 
 static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
@@ -70,9 +73,8 @@  static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
 	void __user *argp = (void __user *)arg;
 	struct rpmsg_endpoint_info eptinfo;
 	struct rpmsg_channel_info chinfo;
-
-	if (cmd != RPMSG_CREATE_EPT_IOCTL)
-		return -EINVAL;
+	struct rpmsg_device *rpdev;
+	int ret = 0;
 
 	if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
 		return -EFAULT;
@@ -82,7 +84,26 @@  static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
 	chinfo.src = eptinfo.src;
 	chinfo.dst = eptinfo.dst;
 
-	return rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
+	mutex_lock(&ctrldev->ctrl_lock);
+	switch (cmd) {
+	case RPMSG_CREATE_EPT_IOCTL:
+		ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
+		break;
+
+	case RPMSG_CREATE_DEV_IOCTL:
+		rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo);
+		if (!rpdev) {
+			dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name);
+			ret = -ENXIO;
+		}
+		break;
+
+	default:
+		ret = -EINVAL;
+	}
+	mutex_unlock(&ctrldev->ctrl_lock);
+
+	return ret;
 };
 
 static const struct file_operations rpmsg_ctrldev_fops = {
@@ -119,6 +140,7 @@  static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev)
 	device_initialize(dev);
 	dev->parent = &rpdev->dev;
 
+	mutex_init(&ctrldev->ctrl_lock);
 	cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
 	ctrldev->cdev.owner = THIS_MODULE;
 
diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h
index f5ca8740f3fb..f9d5a74e7801 100644
--- a/include/uapi/linux/rpmsg.h
+++ b/include/uapi/linux/rpmsg.h
@@ -33,4 +33,9 @@  struct rpmsg_endpoint_info {
  */
 #define RPMSG_DESTROY_EPT_IOCTL	_IO(0xb5, 0x2)
 
+/**
+ * Instantiate a rpmsg service device.
+ */
+#define RPMSG_CREATE_DEV_IOCTL	_IOW(0xb5, 0x3, struct rpmsg_endpoint_info)
+
 #endif