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From: Jason Gunthorpe <jgg@nvidia.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	kvm@vger.kernel.org, "Rafael J. Wysocki" <rafael@kernel.org>
Subject: Re: [PATCH 05/10] driver core: Export device_driver_attach()
Date: Tue, 8 Jun 2021 09:33:28 -0300	[thread overview]
Message-ID: <20210608123328.GB1002214@nvidia.com> (raw)
In-Reply-To: <YL8L9Vgy1FDGUypL@infradead.org>

On Tue, Jun 08, 2021 at 07:19:33AM +0100, Christoph Hellwig wrote:
> On Mon, Jun 07, 2021 at 09:55:47PM -0300, Jason Gunthorpe wrote:
> > This is intended as a replacement API for device_bind_driver(). It has at
> > least the following benefits:
> > 
> > - Internal locking. Few of the users of device_bind_driver() follow the
> >   locking rules
> > 
> > - Calls device driver probe() internally. Notably this means that devm
> >   support for probe works correctly as probe() error will call
> >   devres_release_all()
> > 
> > - struct device_driver -> dev_groups is supported
> > 
> > - Simplified calling convention, no need to manually call probe().
> 
> Btw, it would be nice to convert at least one existing user of
> device_bind_driver to show this.  Also maybe Cc all maintainers of
> subsystems using device_bind_driver so that they get a headsup and
> maybe quickly move over?

Sure. I would do the MDIO phy, though I cann't test that code, I'm at
least familiar with it..

> > @@ -1077,6 +1079,7 @@ int device_driver_attach(struct device_driver *drv, struct device *dev)
> >  		return -EAGAIN;
> >  	return ret;
> >  }
> > +EXPORT_SYMBOL_GPL(device_driver_attach);
> 
> Ok, this means my earlier suggestions of a locked driver_probe_device
> helper needs a different name as we really don't want to expose flags
> and always return -EAGAIN here.  So maybe rename driver_probe_device
> to __driver_probe_device, have a driver_probe_device around it that
> does the locking and keep device_driver_attach for the newly exported
> API.

I put the squashing to -EAGAIN here specifically because of this
export. EPROBE_DEFER should not be returned to userspace and if I leak
it out to drivers at this point then one of them will eventually do
it wrong, as we saw already in sysfs bind_store

Jason

  reply	other threads:[~2021-06-08 12:33 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-08  0:55 [PATCH 00/10] Allow mdev drivers to directly create the vfio_device Jason Gunthorpe
2021-06-08  0:55 ` [Intel-gfx] " Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 01/10] driver core: Do not continue searching for drivers if deferred probe is used Jason Gunthorpe
2021-06-08  5:51   ` Christoph Hellwig
2021-06-08  6:44   ` Greg Kroah-Hartman
2021-06-08 12:16     ` Jason Gunthorpe
2021-06-08 13:13       ` Greg Kroah-Hartman
2021-06-08 13:53         ` Jason Gunthorpe
2021-06-08  7:35   ` Greg Kroah-Hartman
2021-06-08 12:17     ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 02/10] driver core: Pull required checks into driver_probe_device() Jason Gunthorpe
2021-06-08  5:59   ` Christoph Hellwig
2021-06-08 12:21     ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 03/10] driver core: Flow the return code from ->probe() through to sysfs bind Jason Gunthorpe
2021-06-08  6:07   ` Christoph Hellwig
2021-06-08 23:53     ` Jason Gunthorpe
2021-06-08  6:47   ` Greg Kroah-Hartman
2021-06-08 12:30     ` Jason Gunthorpe
2021-06-08 13:16       ` Greg Kroah-Hartman
2021-06-08 14:03         ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 04/10] driver core: Don't return EPROBE_DEFER to userspace during " Jason Gunthorpe
2021-06-08  6:14   ` Christoph Hellwig
2021-06-08  7:37   ` Greg Kroah-Hartman
2021-06-08  0:55 ` [PATCH 05/10] driver core: Export device_driver_attach() Jason Gunthorpe
2021-06-08  6:19   ` Christoph Hellwig
2021-06-08 12:33     ` Jason Gunthorpe [this message]
2021-06-08  0:55 ` [PATCH 06/10] vfio/mdev: Remove CONFIG_VFIO_MDEV_DEVICE Jason Gunthorpe
2021-06-08  0:55   ` [Intel-gfx] " Jason Gunthorpe
2021-06-08  6:20   ` Christoph Hellwig
2021-06-08  6:20     ` [Intel-gfx] " Christoph Hellwig
2021-06-11 12:40   ` Cornelia Huck
2021-06-11 12:40     ` [Intel-gfx] " Cornelia Huck
2021-06-14 12:35     ` Jason Gunthorpe
2021-06-14 12:35       ` [Intel-gfx] " Jason Gunthorpe
2021-06-14 12:35       ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 07/10] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind Jason Gunthorpe
2021-06-08  6:21   ` Christoph Hellwig
2021-06-08  0:55 ` [PATCH 08/10] vfio/mtty: Convert to use vfio_register_group_dev() Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 09/10] vfio/mdpy: " Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 10/10] vfio/mbochs: " Jason Gunthorpe
2021-06-08  6:22 ` [PATCH 00/10] Allow mdev drivers to directly create the vfio_device Christoph Hellwig
2021-06-08  6:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-14 14:34 ` Kirti Wankhede
2021-06-14 14:34   ` [Intel-gfx] " Kirti Wankhede
2021-06-14 14:34   ` Kirti Wankhede
2021-06-14 14:36   ` Jason Gunthorpe
2021-06-14 14:36     ` [Intel-gfx] " Jason Gunthorpe
2021-06-14 14:36     ` Jason Gunthorpe
2021-06-14 15:08 Allow mdev drivers to directly create the vfio_device (v2 / alternative) Christoph Hellwig
2021-06-14 15:08 ` [PATCH 05/10] driver core: Export device_driver_attach() Christoph Hellwig
2021-06-15  5:20   ` Greg Kroah-Hartman
2021-06-15  5:20     ` Greg Kroah-Hartman
2021-06-15 10:49   ` Cornelia Huck
2021-06-15 10:49     ` Cornelia Huck
2021-06-15 13:35 Allow mdev drivers to directly create the vfio_device (v3) Christoph Hellwig
2021-06-15 13:35 ` [PATCH 05/10] driver core: Export device_driver_attach() Christoph Hellwig
2021-06-15 14:10   ` Greg Kroah-Hartman
2021-06-15 14:10     ` Greg Kroah-Hartman
2021-06-17 14:22 Allow mdev drivers to directly create the vfio_device (v4) Christoph Hellwig
2021-06-17 14:22 ` [PATCH 05/10] driver core: Export device_driver_attach() Christoph Hellwig

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