diff mbox

[v10,01/19] vfio: Mediated device Core driver

Message ID c339d6f5-8dba-f69b-b0bc-baf45f2d5ab5@nvidia.com (mailing list archive)
State New, archived
Headers show

Commit Message

Kirti Wankhede Oct. 29, 2016, 10:06 a.m. UTC
On 10/29/2016 10:00 AM, Jike Song wrote:
> On 10/27/2016 05:29 AM, Kirti Wankhede wrote:
>> +int mdev_register_device(struct device *dev, const struct parent_ops *ops)
>> +{
>> +	int ret;
>> +	struct parent_device *parent;
>> +
>> +	/* check for mandatory ops */
>> +	if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
>> +		return -EINVAL;
>> +
>> +	dev = get_device(dev);
>> +	if (!dev)
>> +		return -EINVAL;
>> +
>> +	mutex_lock(&parent_list_lock);
>> +
>> +	/* Check for duplicate */
>> +	parent = __find_parent_device(dev);
>> +	if (parent) {
>> +		ret = -EEXIST;
>> +		goto add_dev_err;
>> +	}
>> +
>> +	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
>> +	if (!parent) {
>> +		ret = -ENOMEM;
>> +		goto add_dev_err;
>> +	}
>> +
>> +	kref_init(&parent->ref);
>> +	mutex_init(&parent->lock);
>> +
>> +	parent->dev = dev;
>> +	parent->ops = ops;
>> +
>> +	ret = parent_create_sysfs_files(parent);
>> +	if (ret) {
>> +		mutex_unlock(&parent_list_lock);
>> +		mdev_put_parent(parent);
>> +		return ret;
>> +	}
>> +
>> +	ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
>> +	if (ret)
>> +		dev_warn(dev, "Failed to create compatibility class link\n");
>> +
> 
> Hi Kirti,
> 
> Like I replied to previous version:
> 
> 	http://www.spinics.net/lists/kvm/msg139331.html
> 

Hi Jike,

I saw your reply but by that time v10 version of patch series was out
for review.

> You can always check if mdev_bus_compat_class already registered
> here, and register it if not yet. Same logic should be adopted to
> mdev_init.
> 
> Current implementation will simply panic if configured as builtin,
> which is rare but far from impossible.
> 

Can you verify attached patch with v10 patch-set whether this works for you?
I'll incorporate this change in my next version.

Thanks,
Kirti
From: Kirti Wankhede <kwankhede@nvidia.com>
Date: Sat, 29 Oct 2016 15:12:01 +0530
Subject: [PATCH 1/1] Register mdev_bus class on first mdev_device_register

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
---
 drivers/vfio/mdev/mdev_core.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

Comments

Jike Song Oct. 29, 2016, 6:11 p.m. UTC | #1
On 10/29/2016 06:06 PM, Kirti Wankhede wrote:
> 
> 
> On 10/29/2016 10:00 AM, Jike Song wrote:
>> On 10/27/2016 05:29 AM, Kirti Wankhede wrote:
>>> +int mdev_register_device(struct device *dev, const struct parent_ops *ops)
>>> +{
>>> +	int ret;
>>> +	struct parent_device *parent;
>>> +
>>> +	/* check for mandatory ops */
>>> +	if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
>>> +		return -EINVAL;
>>> +
>>> +	dev = get_device(dev);
>>> +	if (!dev)
>>> +		return -EINVAL;
>>> +
>>> +	mutex_lock(&parent_list_lock);
>>> +
>>> +	/* Check for duplicate */
>>> +	parent = __find_parent_device(dev);
>>> +	if (parent) {
>>> +		ret = -EEXIST;
>>> +		goto add_dev_err;
>>> +	}
>>> +
>>> +	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
>>> +	if (!parent) {
>>> +		ret = -ENOMEM;
>>> +		goto add_dev_err;
>>> +	}
>>> +
>>> +	kref_init(&parent->ref);
>>> +	mutex_init(&parent->lock);
>>> +
>>> +	parent->dev = dev;
>>> +	parent->ops = ops;
>>> +
>>> +	ret = parent_create_sysfs_files(parent);
>>> +	if (ret) {
>>> +		mutex_unlock(&parent_list_lock);
>>> +		mdev_put_parent(parent);
>>> +		return ret;
>>> +	}
>>> +
>>> +	ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
>>> +	if (ret)
>>> +		dev_warn(dev, "Failed to create compatibility class link\n");
>>> +
>>
>> Hi Kirti,
>>
>> Like I replied to previous version:
>>
>> 	http://www.spinics.net/lists/kvm/msg139331.html
>>
> 
> Hi Jike,
> 
> I saw your reply but by that time v10 version of patch series was out
> for review.
> 

Ah..yes, I forgot that :)

>> You can always check if mdev_bus_compat_class already registered
>> here, and register it if not yet. Same logic should be adopted to
>> mdev_init.
>>
>> Current implementation will simply panic if configured as builtin,
>> which is rare but far from impossible.
>>
> 
> Can you verify attached patch with v10 patch-set whether this works for you?
> I'll incorporate this change in my next version.
> 

Seems cool. But would you please also keep the register in mdev_init(),
just check the 'in case it was already registered' case? Thanks!

--
Thanks,
Jike

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Kirti Wankhede Nov. 2, 2016, 7:59 a.m. UTC | #2
On 10/29/2016 11:41 PM, Jike Song wrote:
> On 10/29/2016 06:06 PM, Kirti Wankhede wrote:
>>
>>
>> On 10/29/2016 10:00 AM, Jike Song wrote:
>>> On 10/27/2016 05:29 AM, Kirti Wankhede wrote:
>>>> +int mdev_register_device(struct device *dev, const struct parent_ops *ops)
>>>> +{
>>>> +	int ret;
>>>> +	struct parent_device *parent;
>>>> +
>>>> +	/* check for mandatory ops */
>>>> +	if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
>>>> +		return -EINVAL;
>>>> +
>>>> +	dev = get_device(dev);
>>>> +	if (!dev)
>>>> +		return -EINVAL;
>>>> +
>>>> +	mutex_lock(&parent_list_lock);
>>>> +
>>>> +	/* Check for duplicate */
>>>> +	parent = __find_parent_device(dev);
>>>> +	if (parent) {
>>>> +		ret = -EEXIST;
>>>> +		goto add_dev_err;
>>>> +	}
>>>> +
>>>> +	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
>>>> +	if (!parent) {
>>>> +		ret = -ENOMEM;
>>>> +		goto add_dev_err;
>>>> +	}
>>>> +
>>>> +	kref_init(&parent->ref);
>>>> +	mutex_init(&parent->lock);
>>>> +
>>>> +	parent->dev = dev;
>>>> +	parent->ops = ops;
>>>> +
>>>> +	ret = parent_create_sysfs_files(parent);
>>>> +	if (ret) {
>>>> +		mutex_unlock(&parent_list_lock);
>>>> +		mdev_put_parent(parent);
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
>>>> +	if (ret)
>>>> +		dev_warn(dev, "Failed to create compatibility class link\n");
>>>> +
>>>
>>> Hi Kirti,
>>>
>>> Like I replied to previous version:
>>>
>>> 	http://www.spinics.net/lists/kvm/msg139331.html
>>>
>>
>> Hi Jike,
>>
>> I saw your reply but by that time v10 version of patch series was out
>> for review.
>>
> 
> Ah..yes, I forgot that :)
> 
>>> You can always check if mdev_bus_compat_class already registered
>>> here, and register it if not yet. Same logic should be adopted to
>>> mdev_init.
>>>
>>> Current implementation will simply panic if configured as builtin,
>>> which is rare but far from impossible.
>>>
>>
>> Can you verify attached patch with v10 patch-set whether this works for you?
>> I'll incorporate this change in my next version.
>>
> 
> Seems cool. But would you please also keep the register in mdev_init(),
> just check the 'in case it was already registered' case? Thanks!
> 

The class is used only to keep symbolic to the devices which are
registered to mdev framework. So I think its ok to register this class
when first device is registered.

Thanks,
Kirti
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Jike Song Nov. 2, 2016, 10:31 a.m. UTC | #3
On 11/02/2016 03:59 PM, Kirti Wankhede wrote:
> On 10/29/2016 11:41 PM, Jike Song wrote:
>> On 10/29/2016 06:06 PM, Kirti Wankhede wrote:
>>>
>>>
>>> On 10/29/2016 10:00 AM, Jike Song wrote:
>>>> On 10/27/2016 05:29 AM, Kirti Wankhede wrote:
>>>>> +int mdev_register_device(struct device *dev, const struct parent_ops *ops)
>>>>> +{
>>>>> +	int ret;
>>>>> +	struct parent_device *parent;
>>>>> +
>>>>> +	/* check for mandatory ops */
>>>>> +	if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
>>>>> +		return -EINVAL;
>>>>> +
>>>>> +	dev = get_device(dev);
>>>>> +	if (!dev)
>>>>> +		return -EINVAL;
>>>>> +
>>>>> +	mutex_lock(&parent_list_lock);
>>>>> +
>>>>> +	/* Check for duplicate */
>>>>> +	parent = __find_parent_device(dev);
>>>>> +	if (parent) {
>>>>> +		ret = -EEXIST;
>>>>> +		goto add_dev_err;
>>>>> +	}
>>>>> +
>>>>> +	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
>>>>> +	if (!parent) {
>>>>> +		ret = -ENOMEM;
>>>>> +		goto add_dev_err;
>>>>> +	}
>>>>> +
>>>>> +	kref_init(&parent->ref);
>>>>> +	mutex_init(&parent->lock);
>>>>> +
>>>>> +	parent->dev = dev;
>>>>> +	parent->ops = ops;
>>>>> +
>>>>> +	ret = parent_create_sysfs_files(parent);
>>>>> +	if (ret) {
>>>>> +		mutex_unlock(&parent_list_lock);
>>>>> +		mdev_put_parent(parent);
>>>>> +		return ret;
>>>>> +	}
>>>>> +
>>>>> +	ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
>>>>> +	if (ret)
>>>>> +		dev_warn(dev, "Failed to create compatibility class link\n");
>>>>> +
>>>>
>>>> Hi Kirti,
>>>>
>>>> Like I replied to previous version:
>>>>
>>>> 	http://www.spinics.net/lists/kvm/msg139331.html
>>>>
>>>
>>> Hi Jike,
>>>
>>> I saw your reply but by that time v10 version of patch series was out
>>> for review.
>>>
>>
>> Ah..yes, I forgot that :)
>>
>>>> You can always check if mdev_bus_compat_class already registered
>>>> here, and register it if not yet. Same logic should be adopted to
>>>> mdev_init.
>>>>
>>>> Current implementation will simply panic if configured as builtin,
>>>> which is rare but far from impossible.
>>>>
>>>
>>> Can you verify attached patch with v10 patch-set whether this works for you?
>>> I'll incorporate this change in my next version.
>>>
>>
>> Seems cool. But would you please also keep the register in mdev_init(),
>> just check the 'in case it was already registered' case? Thanks!
>>
> 
> The class is used only to keep symbolic to the devices which are
> registered to mdev framework. So I think its ok to register this class
> when first device is registered.
> 

That's also cool :-)

So if you like it:

Reviewed-by: Jike Song <jike.song@intel.com>


--
Thanks,
Jike

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diff mbox

Patch

diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 9d8fa5c91c2e..54c59f325336 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -187,13 +187,18 @@  int mdev_register_device(struct device *dev, const struct parent_ops *ops)
 	parent->dev = dev;
 	parent->ops = ops;
 
-	ret = parent_create_sysfs_files(parent);
-	if (ret) {
-		mutex_unlock(&parent_list_lock);
-		mdev_put_parent(parent);
-		return ret;
+	if (!mdev_bus_compat_class) {
+		mdev_bus_compat_class = class_compat_register("mdev_bus");
+		if (!mdev_bus_compat_class) {
+			ret = -ENOMEM;
+			goto add_dev_err;
+		}
 	}
 
+	ret = parent_create_sysfs_files(parent);
+	if (ret)
+		goto add_dev_err;
+
 	ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
 	if (ret)
 		dev_warn(dev, "Failed to create compatibility class link\n");
@@ -206,7 +211,10 @@  int mdev_register_device(struct device *dev, const struct parent_ops *ops)
 
 add_dev_err:
 	mutex_unlock(&parent_list_lock);
-	put_device(dev);
+	if (parent)
+		mdev_put_parent(parent);
+	else
+		put_device(dev);
 	return ret;
 }
 EXPORT_SYMBOL(mdev_register_device);
@@ -354,12 +362,6 @@  static int __init mdev_init(void)
 		return ret;
 	}
 
-	mdev_bus_compat_class = class_compat_register("mdev_bus");
-	if (!mdev_bus_compat_class) {
-		mdev_bus_unregister();
-		return -ENOMEM;
-	}
-
 	/*
 	 * Attempt to load known vfio_mdev.  This gives us a working environment
 	 * without the user needing to explicitly load vfio_mdev driver.
@@ -371,7 +373,9 @@  static int __init mdev_init(void)
 
 static void __exit mdev_exit(void)
 {
-	class_compat_unregister(mdev_bus_compat_class);
+	if (mdev_bus_compat_class)
+		class_compat_unregister(mdev_bus_compat_class);
+
 	mdev_bus_unregister();
 }