Re: [PATCH v9 16/17] vduse: Introduce VDUSE - vDPA Device in Userspace

[Jason Wang]

在 2021/7/13 下午9:27, Dan Carpenter 写道:
> On Tue, Jul 13, 2021 at 04:46:55PM +0800, Xie Yongji wrote:
> > +static int vduse_dev_init_vdpa(struct vduse_dev *dev, const char *name)
> > +{
> > +	struct vduse_vdpa *vdev;
> > +	int ret;
> > +
> > +	if (dev->vdev)
> > +		return -EEXIST;
> > +
> > +	vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, dev->dev,
> > +				 &vduse_vdpa_config_ops, name, true);
> > +	if (!vdev)
> > +		return -ENOMEM;
> This should be an IS_ERR() check instead of a NULL check.


Yes.


> The vdpa_alloc_device() macro is doing something very complicated but
> I'm not sure what.  It calls container_of() and that looks buggy until
> you spot the BUILD_BUG_ON_ZERO() compile time assert which ensures that
> the container_of() is a no-op.
>
> Only one of the callers checks for error pointers correctly so maybe
> it's too complicated or maybe there should be better documentation.


We need better documentation for this macro and fix all the buggy callers.

Yong Ji, want to do that?

Thanks


> regards,
> dan carpenter