From 9c799c224d6ebc5be51065bd3217a2d7eea23b8f Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Fri, 23 Sep 2022 11:26:52 +0200 Subject: vfio/mdev: add mdev available instance checking to the core Many of the mdev drivers use a simple counter for keeping track of the available instances. Move this code to the core code and store the counter in the mdev_parent. Implement it using correct locking, fixing mdpy. Drivers just provide the value in the mdev_driver at registration time and the core code takes care of maintaining it and exposing the value in sysfs. [hch: count instances per-parent instead of per-type, use an atomic_t to avoid taking mdev_list_lock in the show method] Signed-off-by: Jason Gunthorpe Signed-off-by: Christoph Hellwig Reviewed-by: Kevin Tian Reviewed-by: Kirti Wankhede Reviewed-by: Eric Farman Link: https://lore.kernel.org/r/20220923092652.100656-15-hch@lst.de Signed-off-by: Alex Williamson --- drivers/vfio/mdev/mdev_sysfs.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/vfio/mdev/mdev_sysfs.c') diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c index 658b3bf5ed0b..abe3359dd477 100644 --- a/drivers/vfio/mdev/mdev_sysfs.c +++ b/drivers/vfio/mdev/mdev_sysfs.c @@ -108,7 +108,10 @@ static ssize_t available_instances_show(struct mdev_type *mtype, { struct mdev_driver *drv = mtype->parent->mdev_driver; - return sysfs_emit(buf, "%u\n", drv->get_available(mtype)); + if (drv->get_available) + return sysfs_emit(buf, "%u\n", drv->get_available(mtype)); + return sysfs_emit(buf, "%u\n", + atomic_read(&mtype->parent->available_instances)); } static MDEV_TYPE_ATTR_RO(available_instances); -- cgit