/fs/adfs/

When we create an mdev device, we check for duplicates against the
parent device and return -EEXIST if found, but the mdev device
namespace is global since we'll link all devices from the bus.  We do
catch this later in sysfs_do_create_link_sd() to return -EEXIST, but
with it comes a kernel warning and stack trace for trying to create
duplicate sysfs links, which makes it an undesirable response.

Therefore we should really be looking for duplicates across all mdev
parent devices, or as implemented here, against our mdev device list.
Using mdev_list to prevent duplicates means that we can remove
mdev_parent.lock, but in order not to serialize mdev device creation
and removal globally, we add mdev_device.active which allows UUIDs to
be reserved such that we can drop the mdev_list_lock before the mdev
device is fully in place.

Two behavioral notes; first, mdev_parent.lock had the side-effect of
serializing mdev create and remove ops per parent device.  This was
an implementation detail, not an intentional guarantee provided to
the mdev vendor drivers.  Vendor drivers can trivially provide this
serialization internally if necessary.  Second, review comments note
the new -EAGAIN behavior when the device, and in particular the remove
attribute, becomes visible in sysfs.  If a remove is triggered prior
to completion of mdev_device_create() the user will see a -EAGAIN
error.  While the errno is different, receiving an error during this
period is not, the previous implementation returned -ENODEV for the
same condition.  Furthermore, the consistency to the user is improved
in the case where mdev_device_remove_ops() returns error.  Previously
concurrent calls to mdev_device_remove() could see the device
disappear with -ENODEV and return in the case of error.  Now a user
would see -EAGAIN while the device is in this transitory state.

Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Acked-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

vfio-mediated-device.txt: standardize document format 2017-07-14T19:58:10+00:00 Mauro Carvalho Chehab mchehab@s-opensource.com 2017-05-17T12:26:06+00:00 2a26ed8e4afff2bb48c044dc3ad69da19d66debf Each text file under Documentation follows a different format. Some doesn't even have titles! In this specific document, the title, copyright and authorship are added as if it were a C file! Change its representation to follow the adopted standard, using ReST markups for it to be parseable by Sphinx: - convert document preambule to the proper format; - mark literal blocks; - adjust identation; - use numbered lists for references. Reviewed by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

In this specific document, the title, copyright and authorship
are added as if it were a C file!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:
- convert document preambule to the proper format;
- mark literal blocks;
- adjust identation;
- use numbered lists for references.

Reviewed by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

docs: Fix a spelling error in vfio-mediated-device.txt 2017-04-27T21:54:39+00:00 Stan Drozd drozdziak1@gmail.com 2017-04-21T11:07:10+00:00 1c4f128ed1cbadcfcb3c2d654b39268d592f716f This commit fixes a repeated "the" in vfio-mediated-device.txt and reflows the paragraph. Signed-off-by: Stan Drozd <drozdziak1@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>

This commit fixes a repeated "the" in vfio-mediated-device.txt and reflows the
paragraph.

Signed-off-by: Stan Drozd <drozdziak1@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation: vfio-mediated-device.txt: Fix typos 2017-03-17T19:04:53+00:00 Tamara Diaconita diaconitatamara@gmail.com 2017-03-16T15:42:16+00:00 ce8cd407cc825d22858cf25c666aa12873d77419 Correct spelling mistakes in vfio-mediates-device.txt to make documentation clear. Signed-off-by: Tamara Diaconita <diaconita.tamara@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Correct spelling mistakes in vfio-mediates-device.txt to make
documentation clear.

Signed-off-by: Tamara Diaconita <diaconita.tamara@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

vfio-mdev: Make mdev_parent private 2016-12-30T15:13:41+00:00 Alex Williamson alex.williamson@redhat.com 2016-12-30T15:13:41+00:00 9372e6feaafb65d88f667ffb5b7b425f8568344f Rather than hoping for good behavior by marking some elements internal, enforce it by making the entire structure private and creating an accessor function for the one useful external field. Cc: Zhenyu Wang <zhenyuw@linux.intel.com> Cc: Zhi Wang <zhi.a.wang@intel.com> Cc: Jike Song <jike.song@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed by: Kirti Wankhede <kwankhede@nvidia.com>

Rather than hoping for good behavior by marking some elements
internal, enforce it by making the entire structure private and
creating an accessor function for the one useful external field.

Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Jike Song <jike.song@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed by: Kirti Wankhede <kwankhede@nvidia.com>

vfio-mdev: de-polute the namespace, rename parent_device & parent_ops 2016-12-30T15:13:38+00:00 Alex Williamson alex.williamson@redhat.com 2016-12-30T15:13:38+00:00 42930553a7c11f06351bc08b889808d0f6020f08 Add an mdev_ prefix so we're not poluting the namespace so much. Cc: Zhenyu Wang <zhenyuw@linux.intel.com> Cc: Zhi Wang <zhi.a.wang@intel.com> Cc: Jike Song <jike.song@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed by: Kirti Wankhede <kwankhede@nvidia.com>

Add an mdev_ prefix so we're not poluting the namespace so much.

Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Jike Song <jike.song@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed by: Kirti Wankhede <kwankhede@nvidia.com>

docs: Sample driver to demonstrate how to use Mediated device framework. 2016-11-17T16:18:44+00:00 Kirti Wankhede kwankhede@nvidia.com 2016-11-16T20:46:33+00:00 9d1a546c53b4c1c378b0f34de84ddee2c7d4c90c The Sample driver creates mdev device that simulates serial port over PCI card. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Neo Jia <cjia@nvidia.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

The Sample driver creates mdev device that simulates serial port over PCI
card.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

docs: Add Documentation for Mediated devices 2016-11-17T15:33:20+00:00 Kirti Wankhede kwankhede@nvidia.com 2016-11-16T20:46:31+00:00 8e1c5a4048b89d04d8d1ee655ce1f685e6fddde4 Add file Documentation/vfio-mediated-device.txt that include details of mediated device framework. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Neo Jia <cjia@nvidia.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Add file Documentation/vfio-mediated-device.txt that include details of
mediated device framework.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>