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 Fixes conditions with mdev device life cycle APIs This series is tested using (a) mtty with VM using vfio_mdev driver for positive tests. (b) mtty with vfio_mdev with error race condition cases of create, remove and unloading of mtty driver. (c) 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: --- 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 (7): 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: Fix race conditions with mdev device life cycle APIs drivers/vfio/mdev/mdev_core.c | 102 ++++++++++++++++++++++++++++----------- drivers/vfio/mdev/mdev_private.h | 7 ++- drivers/vfio/mdev/mdev_sysfs.c | 2 +- include/linux/mdev.h | 21 ++++---- 4 files changed, 91 insertions(+), 41 deletions(-) -- 1.8.3.1
