Re: [PATCH V2 3/5] vDPA: introduce vDPA bus

[Jason Wang]

On 2020/2/12 äå8:51, Jason Gunthorpe wrote:
> On Wed, Feb 12, 2020 at 03:55:31PM +0800, Jason Wang wrote:
> > > The ida_simple_remove should probably be part of the class release
> > > function to make everything work right
> > It looks to me bus instead of class is the correct abstraction here since
> > the devices share a set of programming interface but not the semantics.
> device_release() doesn't call the bus release?


What it did is:

ÂÂÂÂÂÂÂ if (dev->release)
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ dev->release(dev);
ÂÂÂÂÂÂÂ else if (dev->type && dev->type->release)
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ dev->type->release(dev);
ÂÂÂÂÂÂÂ else if (dev->class && dev->class->dev_release)
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ dev->class->dev_release(dev);
ÂÂÂÂÂÂÂ else
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ WARN(1, KERN_ERR "Device '%s' does not have a release() 
function, it is broken and must be fixed. See Documentation/kobject.txt.\n",
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ dev_name(dev));

So it looks not.


>   You have dev, type or
> class to choose from. Type is rarely used and doesn't seem to be used
> by vdpa, so class seems the right choice
>
> Jason


Yes, but my understanding is class and bus are mutually exclusive. So we 
can't add a class to a device which is already attached on a bus.

Thanks