From: Dan Williams <dan.j.williams@intel.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>,
Alex Williamson <alex.williamson@redhat.com>,
Cornelia Huck <cohuck@redhat.com>,
kvm@vger.kernel.org, Kirti Wankhede <kwankhede@nvidia.com>,
"Raj, Ashok" <ashok.raj@intel.com>,
Daniel Vetter <daniel@ffwll.ch>,
Leon Romanovsky <leonro@nvidia.com>,
Max Gurtovoy <mgurtovoy@nvidia.com>,
Tarun Gupta <targupta@nvidia.com>
Subject: Re: [PATCH v2 02/13] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind
Date: Wed, 28 Apr 2021 00:56:21 -0700 [thread overview]
Message-ID: <CAPcyv4g=MFtZMVZPn8AtTX6NyweF25nuFNVBu7pg_QSP+EGE+g@mail.gmail.com> (raw)
In-Reply-To: <20210428060300.GA4092@lst.de>
On Tue, Apr 27, 2021 at 11:04 PM Christoph Hellwig <hch@lst.de> wrote:
>
> On Mon, Apr 26, 2021 at 05:00:04PM -0300, Jason Gunthorpe wrote:
> > +/*
> > + * mdev drivers can refuse to bind during probe(), in this case we want to fail
> > + * the creation of the mdev all the way back to sysfs. This is a weird model
> > + * that doesn't fit in the driver core well, nor does it seem to appear any
> > + * place else in the kernel, so use a simple hack.
> > + */
> > +static int mdev_bind_driver(struct mdev_device *mdev)
> > +{
> > + struct mdev_driver *drv = mdev->type->parent->ops->device_driver;
> > + int ret;
> > +
> > + if (!drv)
> > + drv = &vfio_mdev_driver;
> > +
> > + while (1) {
> > + device_lock(&mdev->dev);
> > + if (mdev->dev.driver == &drv->driver) {
> > + ret = 0;
> > + goto out_unlock;
> > + }
> > + if (mdev->probe_err) {
> > + ret = mdev->probe_err;
> > + goto out_unlock;
> > + }
> > + device_unlock(&mdev->dev);
> > + ret = device_attach(&mdev->dev);
> > + if (ret)
> > + return ret;
> > + mdev->probe_err = -EINVAL;
> > + }
> > + return 0;
> > +
> > +out_unlock:
> > + device_unlock(&mdev->dev);
> > + return ret;
> > +}
>
> > +++ b/drivers/vfio/mdev/mdev_driver.c
> > @@ -49,7 +49,7 @@ static int mdev_probe(struct device *dev)
> > return ret;
> >
> > if (drv->probe) {
> > - ret = drv->probe(mdev);
> > + ret = mdev->probe_err = drv->probe(mdev);
> > if (ret)
> > mdev_detach_iommu(mdev);
> > }
>
> > return 0;
> > }
> >
> > +static int mdev_match(struct device *dev, struct device_driver *drv)
> > +{
> > + struct mdev_device *mdev = to_mdev_device(dev);
> > + struct mdev_driver *target = mdev->type->parent->ops->device_driver;
> > +
> > + /*
> > + * The ops specify the device driver to connect, fall back to the old
> > + * shim driver if the driver hasn't been converted.
> > + */
> > + if (!target)
> > + target = &vfio_mdev_driver;
> > + return drv == &target->driver;
> > +}
>
> I still think this going the wrong way. Why can't we enhance the core
> driver code with a version of device_bind_driver() that does call into
> ->probe? That probably seems like a better model for those existing
> direct users of device_bind_driver or device_attach with a pre-set
> ->drv anyway.
Wouldn't that just be "export device_driver_attach()" so that drivers
can implement their own custom bind implementation?
next prev parent reply other threads:[~2021-04-28 7:56 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-26 20:00 [PATCH v2 00/13] Remove vfio_mdev.c, mdev_parent_ops and more Jason Gunthorpe
2021-04-26 20:00 ` [PATCH v2 01/13] vfio/mdev: Remove CONFIG_VFIO_MDEV_DEVICE Jason Gunthorpe
2021-04-27 11:05 ` Cornelia Huck
2021-04-26 20:00 ` [PATCH v2 02/13] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind Jason Gunthorpe
2021-04-27 12:32 ` Cornelia Huck
2021-04-27 23:20 ` Jason Gunthorpe
2021-04-28 6:03 ` Christoph Hellwig
2021-04-28 7:56 ` Dan Williams [this message]
2021-04-28 12:41 ` Christoph Hellwig
2021-04-28 14:00 ` Jason Gunthorpe
2021-04-28 19:58 ` Dan Williams
2021-04-28 23:38 ` Jason Gunthorpe
2021-04-29 0:00 ` Dave Jiang
2021-05-26 0:42 ` Jason Gunthorpe
2021-05-26 1:42 ` Dan Williams
2021-05-27 11:44 ` Christoph Hellwig
2021-05-27 14:53 ` Jason Gunthorpe
2021-05-27 15:13 ` Christoph Hellwig
2021-04-29 6:51 ` Christoph Hellwig
2021-05-04 9:36 ` Christoph Hellwig
2021-05-04 11:30 ` Jason Gunthorpe
2021-04-28 6:44 ` Leon Romanovsky
2021-04-28 14:14 ` Jason Gunthorpe
2021-04-28 14:24 ` Leon Romanovsky
2021-04-26 20:00 ` [PATCH v2 03/13] vfio/mtty: Convert to use vfio_register_group_dev() Jason Gunthorpe
2021-04-26 20:00 ` [PATCH v2 04/13] vfio/mdpy: " Jason Gunthorpe
2021-04-26 20:00 ` [PATCH v2 05/13] vfio/mbochs: " Jason Gunthorpe
2021-04-26 20:00 ` [PATCH v2 07/13] vfio/ccw: " Jason Gunthorpe
2021-04-27 20:06 ` Eric Farman
2021-04-27 22:10 ` Jason Gunthorpe
2021-04-28 12:55 ` Eric Farman
2021-04-28 13:21 ` Jason Gunthorpe
2021-04-28 17:09 ` Cornelia Huck
2021-04-28 17:20 ` Jason Gunthorpe
2021-04-29 11:58 ` Cornelia Huck
2021-04-29 18:13 ` Jason Gunthorpe
2021-04-30 12:31 ` Cornelia Huck
2021-04-30 17:19 ` Jason Gunthorpe
2021-05-03 10:54 ` s390 common I/O layer locking (was: [PATCH v2 07/13] vfio/ccw: Convert to use vfio_register_group_dev()) Cornelia Huck
2021-05-04 15:10 ` s390 common I/O layer locking Vineeth Vijayan
2021-07-24 13:24 ` Christoph Hellwig
2021-08-03 14:27 ` Vineeth Vijayan
2021-08-10 15:00 ` Cornelia Huck
2021-04-26 20:00 ` [PATCH v2 09/13] vfio/mdev: Remove vfio_mdev.c Jason Gunthorpe
2021-04-28 6:07 ` Christoph Hellwig
2021-04-28 6:36 ` Greg Kroah-Hartman
2021-04-28 12:53 ` Jason Gunthorpe
2021-04-29 6:53 ` Christoph Hellwig
2021-04-29 6:56 ` Greg Kroah-Hartman
2021-05-03 17:32 ` Jason Gunthorpe
2021-05-04 9:38 ` Christoph Hellwig
2021-05-04 16:20 ` Jason Gunthorpe
2021-04-26 20:00 ` [PATCH v2 10/13] vfio/mdev: Remove mdev_parent_ops dev_attr_groups Jason Gunthorpe
2021-04-26 20:00 ` [PATCH v2 11/13] vfio/mdev: Remove mdev_parent_ops Jason Gunthorpe
2021-04-26 20:00 ` [PATCH v2 12/13] vfio/mdev: Use the driver core to create the 'remove' file Jason Gunthorpe
2021-04-26 20:00 ` [PATCH v2 13/13] vfio/mdev: Remove mdev drvdata Jason Gunthorpe
2021-04-27 21:30 ` [PATCH v2 00/13] Remove vfio_mdev.c, mdev_parent_ops and more Alex Williamson
2021-04-27 22:20 ` Jason Gunthorpe
2021-04-27 22:49 ` Alex Williamson
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