diff options
| author | Alex Williamson <alex.williamson@redhat.com> | 2021-06-25 15:20:06 -0600 |
|---|---|---|
| committer | Alex Williamson <alex.williamson@redhat.com> | 2021-06-28 14:09:01 -0600 |
| commit | 97d0a6874478802b68e3bea7aa9b9a333d257182 (patch) | |
| tree | fdc11ba1b81e755a993fc1d80200e5dc0159ad33 /samples | |
| parent | 0dd1b7fc3e7d30802d5839f6bf8957023b437ad4 (diff) | |
vfio/mtty: Enforce available_instances
The sample mtty mdev driver doesn't actually enforce the number of
device instances it claims are available. Implement this properly.
Link: https://lore.kernel.org/r/162465624894.3338367.12935940647049917981.stgit@omen
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'samples')
| -rw-r--r-- | samples/vfio-mdev/mtty.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index ffbaf07a17ea..8b26fecc4afe 100644 --- a/samples/vfio-mdev/mtty.c +++ b/samples/vfio-mdev/mtty.c @@ -144,7 +144,7 @@ struct mdev_state { int nr_ports; }; -static atomic_t mdev_used_ports; +static atomic_t mdev_avail_ports = ATOMIC_INIT(MAX_MTTYS); static const struct file_operations vd_fops = { .owner = THIS_MODULE, @@ -707,11 +707,20 @@ static int mtty_probe(struct mdev_device *mdev) { struct mdev_state *mdev_state; int nr_ports = mdev_get_type_group_id(mdev) + 1; + int avail_ports = atomic_read(&mdev_avail_ports); int ret; + do { + if (avail_ports < nr_ports) + return -ENOSPC; + } while (!atomic_try_cmpxchg(&mdev_avail_ports, + &avail_ports, avail_ports - nr_ports)); + mdev_state = kzalloc(sizeof(struct mdev_state), GFP_KERNEL); - if (mdev_state == NULL) + if (mdev_state == NULL) { + atomic_add(nr_ports, &mdev_avail_ports); return -ENOMEM; + } vfio_init_group_dev(&mdev_state->vdev, &mdev->dev, &mtty_dev_ops); @@ -724,6 +733,7 @@ static int mtty_probe(struct mdev_device *mdev) if (mdev_state->vconfig == NULL) { kfree(mdev_state); + atomic_add(nr_ports, &mdev_avail_ports); return -ENOMEM; } @@ -735,9 +745,9 @@ static int mtty_probe(struct mdev_device *mdev) ret = vfio_register_group_dev(&mdev_state->vdev); if (ret) { kfree(mdev_state); + atomic_add(nr_ports, &mdev_avail_ports); return ret; } - atomic_add(mdev_state->nr_ports, &mdev_used_ports); dev_set_drvdata(&mdev->dev, mdev_state); return 0; @@ -746,12 +756,13 @@ static int mtty_probe(struct mdev_device *mdev) static void mtty_remove(struct mdev_device *mdev) { struct mdev_state *mdev_state = dev_get_drvdata(&mdev->dev); + int nr_ports = mdev_state->nr_ports; - atomic_sub(mdev_state->nr_ports, &mdev_used_ports); vfio_unregister_group_dev(&mdev_state->vdev); kfree(mdev_state->vconfig); kfree(mdev_state); + atomic_add(nr_ports, &mdev_avail_ports); } static int mtty_reset(struct mdev_state *mdev_state) @@ -1271,8 +1282,7 @@ static ssize_t available_instances_show(struct mdev_type *mtype, { unsigned int ports = mtype_get_type_group_id(mtype) + 1; - return sprintf(buf, "%d\n", - (MAX_MTTYS - atomic_read(&mdev_used_ports)) / ports); + return sprintf(buf, "%d\n", atomic_read(&mdev_avail_ports) / ports); } static MDEV_TYPE_ATTR_RO(available_instances); |