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author | Jason Gunthorpe <jgg@nvidia.com> | 2022-09-23 11:26:52 +0200 |
---|---|---|
committer | Alex Williamson <alex.williamson@redhat.com> | 2022-10-04 12:06:58 -0600 |
commit | 9c799c224d6ebc5be51065bd3217a2d7eea23b8f (patch) | |
tree | d09166f170afc9fc32ecfe8205964a6257b81990 /drivers/vfio/mdev/mdev_core.c | |
parent | 685a1537f4c603cfcaf4b9be56ff6a571f7ddd08 (diff) | |
download | linux-stable-9c799c224d6ebc5be51065bd3217a2d7eea23b8f.tar.gz linux-stable-9c799c224d6ebc5be51065bd3217a2d7eea23b8f.tar.bz2 linux-stable-9c799c224d6ebc5be51065bd3217a2d7eea23b8f.zip |
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 <jgg@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Link: https://lore.kernel.org/r/20220923092652.100656-15-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio/mdev/mdev_core.c')
-rw-r--r-- | drivers/vfio/mdev/mdev_core.c | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c index 93f8caf2e5f7..58f91b3bd670 100644 --- a/drivers/vfio/mdev/mdev_core.c +++ b/drivers/vfio/mdev/mdev_core.c @@ -70,6 +70,7 @@ int mdev_register_parent(struct mdev_parent *parent, struct device *dev, parent->mdev_driver = mdev_driver; parent->types = types; parent->nr_types = nr_types; + atomic_set(&parent->available_instances, mdev_driver->max_instances); if (!mdev_bus_compat_class) { mdev_bus_compat_class = class_compat_register("mdev_bus"); @@ -115,14 +116,17 @@ EXPORT_SYMBOL(mdev_unregister_parent); static void mdev_device_release(struct device *dev) { struct mdev_device *mdev = to_mdev_device(dev); - - /* Pairs with the get in mdev_device_create() */ - kobject_put(&mdev->type->kobj); + struct mdev_parent *parent = mdev->type->parent; mutex_lock(&mdev_list_lock); list_del(&mdev->next); + if (!parent->mdev_driver->get_available) + atomic_inc(&parent->available_instances); mutex_unlock(&mdev_list_lock); + /* Pairs with the get in mdev_device_create() */ + kobject_put(&mdev->type->kobj); + dev_dbg(&mdev->dev, "MDEV: destroying\n"); kfree(mdev); } @@ -144,6 +148,18 @@ int mdev_device_create(struct mdev_type *type, const guid_t *uuid) } } + if (!drv->get_available) { + /* + * Note: that non-atomic read and dec is fine here because + * all modifications are under mdev_list_lock. + */ + if (!atomic_read(&parent->available_instances)) { + mutex_unlock(&mdev_list_lock); + return -EUSERS; + } + atomic_dec(&parent->available_instances); + } + mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); if (!mdev) { mutex_unlock(&mdev_list_lock); |