On Tue, 30 Apr 2019 17:49:27 -0500 Parav Pandit <parav@xxxxxxxxxxxx> wrote: > As we would like to use mdev subsystem for wider use case as > discussed in [1], [2] apart from an offline discussion. > This use case is also discussed with wider forum in [4] in track > 'Lightweight NIC HW functions for container offload use cases'. > > This series is prep-work and improves vfio/mdev module in following ways. > > Patch-1 Fixes releasing parent dev reference during error unwinding > mdev parent registration. > Patch-2 Simplifies mdev device for unused kref. > Patch-3 Drops redundant extern prefix of exported symbols. > Patch-4 Returns right error code from vendor driver. > Patch-5 Fixes to use right sysfs remove sequence. > Patch-6 Fixes removing all child devices if one of them fails. > Patch-7 Remove unnecessary inline > Patch-8 Improve the mdev create/remove sequence to match Linux > bus, device model > Patch-9 Avoid recreating remove file on stale device to > eliminate call trace > Patch-10 Fix race conditions of create/remove with parent removal > This is improved version than using srcu as srcu can take > seconds to minutes. > > This series is tested using > (a) mtty with VM using vfio_mdev driver for positive tests and > device removal while device in use by VM using vfio_mdev driver > > (b) mlx5 core driver using RFC patches [3] and internal patches. > Internal patches are large and cannot be combined with this > prep-work patches. It will posted once prep-work completes. > > [1] https://www.spinics.net/lists/netdev/msg556978.html > [2] https://lkml.org/lkml/2019/3/7/696 > [3] https://lkml.org/lkml/2019/3/8/819 > [4] https://netdevconf.org/0x13/session.html?workshop-hardware-offload > > --- > Changelog: > --- > v1->v2: > - Addressed comments from Alex > - Rebased > - Inserted the device checking loop in Patch-6 as original code > - Added patch 7 to 10 > - Added fixes for race condition in create/remove with parent removal > Patch-10 uses simplified refcount and completion, instead of srcu > which might take seconds to minutes on busy system. > - Added fix for device create/remove sequence to match > Linux device, bus model > v0->v1: > - Dropped device placement on bus sequence patch for this series > - Addressed below comments from Alex, Kirti, Maxim. > - Added Review-by tag for already reviewed patches. > - Dropped incorrect patch of put_device(). > - Corrected Fixes commit tag for sysfs remove sequence fix > - Split last 8th patch to smaller refactor and fixes patch > - Following coding style commenting format > - Fixed accidental delete of mutex_lock in mdev_unregister_device > - Renamed remove helped to mdev_device_remove_common(). > - Rebased for uuid/guid change > > Parav Pandit (10): > vfio/mdev: Avoid release parent reference during error path > vfio/mdev: Removed unused kref > vfio/mdev: Drop redundant extern for exported symbols > vfio/mdev: Avoid masking error code to EBUSY > vfio/mdev: Follow correct remove sequence > vfio/mdev: Fix aborting mdev child device removal if one fails > vfio/mdev: Avoid inline get and put parent helpers > vfio/mdev: Improve the create/remove sequence > vfio/mdev: Avoid creating sysfs remove file on stale device removal > vfio/mdev: Synchronize device create/remove with parent removal > > drivers/vfio/mdev/mdev_core.c | 162 +++++++++++++------------------ > drivers/vfio/mdev/mdev_private.h | 9 +- > drivers/vfio/mdev/mdev_sysfs.c | 8 +- > include/linux/mdev.h | 21 ++-- > 4 files changed, 89 insertions(+), 111 deletions(-) > Hi Parav, I applied 1-7 to the vfio next branch for v5.2 since these are mostly previously reviewed or trivial. I'm not ruling out the rest for v5.2 as bug fixes yet, but they require a bit more to digest and hopefully we'll get some feedback from others as well. Thanks, Alex
