diff options
Diffstat (limited to 'drivers/vfio/vfio.c')
| -rw-r--r-- | drivers/vfio/vfio.c | 51 |
1 files changed, 24 insertions, 27 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 259ad282ae5d..842f4507883e 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -76,6 +76,7 @@ struct vfio_group { struct notifier_block nb; struct list_head vfio_next; struct list_head container_next; + atomic_t opened; }; struct vfio_device { @@ -206,6 +207,7 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group) INIT_LIST_HEAD(&group->device_list); mutex_init(&group->device_lock); atomic_set(&group->container_users, 0); + atomic_set(&group->opened, 0); group->iommu_group = iommu_group; group->nb.notifier_call = vfio_iommu_group_notifier; @@ -492,27 +494,6 @@ static int vfio_group_nb_add_dev(struct vfio_group *group, struct device *dev) return 0; } -static int vfio_group_nb_del_dev(struct vfio_group *group, struct device *dev) -{ - struct vfio_device *device; - - /* - * Expect to fall out here. If a device was in use, it would - * have been bound to a vfio sub-driver, which would have blocked - * in .remove at vfio_del_group_dev. Sanity check that we no - * longer track the device, so it's safe to remove. - */ - device = vfio_group_get_device(group, dev); - if (likely(!device)) - return 0; - - WARN("Device %s removed from live group %d!\n", dev_name(dev), - iommu_group_id(group->iommu_group)); - - vfio_device_put(device); - return 0; -} - static int vfio_group_nb_verify(struct vfio_group *group, struct device *dev) { /* We don't care what happens when the group isn't in use */ @@ -529,13 +510,11 @@ static int vfio_iommu_group_notifier(struct notifier_block *nb, struct device *dev = data; /* - * Need to go through a group_lock lookup to get a reference or - * we risk racing a group being removed. Leave a WARN_ON for - * debuging, but if the group no longer exists, a spurious notify - * is harmless. + * Need to go through a group_lock lookup to get a reference or we + * risk racing a group being removed. Ignore spurious notifies. */ group = vfio_group_try_get(group); - if (WARN_ON(!group)) + if (!group) return NOTIFY_OK; switch (action) { @@ -543,7 +522,13 @@ static int vfio_iommu_group_notifier(struct notifier_block *nb, vfio_group_nb_add_dev(group, dev); break; case IOMMU_GROUP_NOTIFY_DEL_DEVICE: - vfio_group_nb_del_dev(group, dev); + /* + * Nothing to do here. If the device is in use, then the + * vfio sub-driver should block the remove callback until + * it is unused. If the device is unused or attached to a + * stub driver, then it should be released and we don't + * care that it will be going away. + */ break; case IOMMU_GROUP_NOTIFY_BIND_DRIVER: pr_debug("%s: Device %s, group %d binding to driver\n", @@ -1236,12 +1221,22 @@ static long vfio_group_fops_compat_ioctl(struct file *filep, static int vfio_group_fops_open(struct inode *inode, struct file *filep) { struct vfio_group *group; + int opened; group = vfio_group_get_from_minor(iminor(inode)); if (!group) return -ENODEV; + /* Do we need multiple instances of the group open? Seems not. */ + opened = atomic_cmpxchg(&group->opened, 0, 1); + if (opened) { + vfio_group_put(group); + return -EBUSY; + } + + /* Is something still in use from a previous open? */ if (group->container) { + atomic_dec(&group->opened); vfio_group_put(group); return -EBUSY; } @@ -1259,6 +1254,8 @@ static int vfio_group_fops_release(struct inode *inode, struct file *filep) vfio_group_try_dissolve_container(group); + atomic_dec(&group->opened); + vfio_group_put(group); return 0; |