From: Jason Gunthorpe <jgg@nvidia.com>
To: Christoph Hellwig <hch@lst.de>
Cc: David Airlie <airlied@linux.ie>,
Tony Krowiak <akrowiak@linux.ibm.com>,
Alex Williamson <alex.williamson@redhat.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
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dri-devel@lists.freedesktop.org,
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Vineeth Vijayan <vneethv@linux.ibm.com>,
Zhi Wang <zhi.a.wang@intel.com>,
"Raj, Ashok" <ashok.raj@intel.com>,
Leon Romanovsky <leonro@nvidia.com>,
Max Gurtovoy <mgurtovoy@nvidia.com>,
Yishai Hadas <yishaih@nvidia.com>,
Zhenyu Wang <zhenyuw@linux.intel.com>
Subject: Re: [PATCH v2 06/14] vfio/fsl: Move to the device set infrastructure
Date: Fri, 23 Jul 2021 10:11:31 -0300 [thread overview]
Message-ID: <20210723131131.GU1117491@nvidia.com> (raw)
In-Reply-To: <20210723122903.GA24436@lst.de>
On Fri, Jul 23, 2021 at 02:29:03PM +0200, Christoph Hellwig wrote:
> On Fri, Jul 23, 2021 at 09:22:27AM -0300, Jason Gunthorpe wrote:
> > > But do we even need the else part? Assingning &mc_dev->dev is
> > > equivalent to the default per-device set anyway, isn't it?
> >
> > Not quite, the default is this:
> >
> > if (!device->dev_set)
> > vfio_assign_device_set(device, device);
> >
> > Where 'device' is the vfio_device itself, the above is connecting to
> > the struct fsl_mc_device.
>
> Isn't there a 1:1 relation?
Yes, but one is a struct device * and the other is a struct
vfio_device *. They don't have the same pointer value.
The above default code has the goal of creating a singleton dev_set
because no other driver can reasonably obtain the 'struct vfio_device
*'.
FSL is using a 'struct device *' as the key and the interesting case
is when two drivers are loaded such that:
mc_dev->dev.parent == &mc_dev->dev
Then they will have the same dev_set and the locking works out. The
vfio_device * can never be == &mc_dev->dev because it is a different
allocation.
Jason
next prev parent reply other threads:[~2021-07-23 13:11 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-20 17:42 [PATCH v2 00/14] Provide core infrastructure for managing open/release Jason Gunthorpe
2021-07-20 17:42 ` [PATCH v2 01/14] vfio/samples: Remove module get/put Jason Gunthorpe
2021-07-23 7:18 ` Christoph Hellwig
2021-07-20 17:42 ` [PATCH v2 02/14] vfio/mbochs: Fix missing error unwind in mbochs_probe() Jason Gunthorpe
2021-07-20 22:01 ` Alex Williamson
2021-07-20 22:49 ` Jason Gunthorpe
2021-07-20 22:54 ` Alex Williamson
2021-07-21 9:18 ` Cornelia Huck
2021-07-21 9:16 ` Cornelia Huck
2021-07-20 17:42 ` [PATCH v2 03/14] vfio: Introduce a vfio_uninit_group_dev() API call Jason Gunthorpe
2021-07-21 11:33 ` Cornelia Huck
2021-07-23 7:18 ` Christoph Hellwig
2021-07-20 17:42 ` [PATCH v2 04/14] vfio: Provide better generic support for open/release vfio_device_ops Jason Gunthorpe
2021-07-22 14:42 ` Cornelia Huck
2021-07-23 7:39 ` Christoph Hellwig
2021-07-23 14:38 ` Jason Gunthorpe
2021-07-20 17:42 ` [PATCH v2 05/14] vfio/samples: Delete useless open/close Jason Gunthorpe
2021-07-23 7:39 ` Christoph Hellwig
2021-07-20 17:42 ` [PATCH v2 06/14] vfio/fsl: Move to the device set infrastructure Jason Gunthorpe
2021-07-23 7:44 ` Christoph Hellwig
2021-07-23 12:22 ` Jason Gunthorpe
2021-07-23 12:29 ` Christoph Hellwig
2021-07-23 13:11 ` Jason Gunthorpe [this message]
2021-07-20 17:42 ` [PATCH v2 07/14] vfio/platform: Use open_device() instead of open coding a refcnt scheme Jason Gunthorpe
2021-07-22 14:48 ` Cornelia Huck
2021-07-23 7:45 ` Christoph Hellwig
2021-07-23 12:23 ` Jason Gunthorpe
2021-07-20 17:42 ` [PATCH v2 08/14] vfio/pci: Move to the device set infrastructure Jason Gunthorpe
2021-07-23 7:47 ` Christoph Hellwig
2021-07-23 12:59 ` Jason Gunthorpe
2021-07-20 17:42 ` [PATCH v2 09/14] vfio/pci: Change vfio_pci_try_bus_reset() to use the dev_set Jason Gunthorpe
2021-07-23 8:05 ` Christoph Hellwig
2021-07-23 13:30 ` Jason Gunthorpe
2021-07-20 17:42 ` [PATCH v2 10/14] vfio/pci: Reorganize VFIO_DEVICE_PCI_HOT_RESET to use the device set Jason Gunthorpe
2021-07-23 8:12 ` Christoph Hellwig
2021-07-23 13:31 ` Jason Gunthorpe
2021-07-20 17:42 ` [PATCH v2 11/14] vfio/mbochs: Fix close when multiple device FDs are open Jason Gunthorpe
2021-07-23 8:13 ` Christoph Hellwig
2021-07-20 17:42 ` [PATCH v2 12/14] vfio/ap,ccw: Fix open/close " Jason Gunthorpe
2021-07-20 17:42 ` [PATCH v2 13/14] vfio/gvt: " Jason Gunthorpe
2021-07-23 8:14 ` Christoph Hellwig
2021-07-20 17:43 ` [PATCH v2 14/14] vfio: Remove struct vfio_device_ops open/release Jason Gunthorpe
2021-07-23 8:14 ` Christoph Hellwig
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