[PATCH 5.18 164/231] vduse: Tie vduse mgmtdev and its device

Greg Kroah-Hartman
2022-07-19T13:05:16Z

From: Parav Pandit <parav@nvidia.com>

[ Upstream commit 0e0348ac3f0a6e6606f1aa5acb1803ada913aa3d ]

vduse devices are not backed by any real devices such as PCI. Hence it
doesn't have any parent device linked to it.

Kernel driver model in [1] suggests to avoid an empty device
release callback.

Hence tie the mgmtdevice object's life cycle to an allocate dummy struct
device instead of static one.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/core-api/kobject.rst?h=v5.18-rc7#n284

Signed-off-by: Parav Pandit <parav@nvidia.com>
Message-Id: <20220613195223.473966-1-parav@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/vdpa/vdpa_user/vduse_dev.c | 60 ++++++++++++++++++------------
1 file changed, 37 insertions(+), 23 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 160e40d03084..02709f8a78bd 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -1475,16 +1475,12 @@ static char *vduse_devnode(struct device *dev, umode_t *mode)
return kasprintf(GFP_KERNEL, "vduse/%s", dev_name(dev));
}

-static void vduse_mgmtdev_release(struct device *dev)
-{
-}
-
-static struct device vduse_mgmtdev = {
- .init_name = "vduse",
- .release = vduse_mgmtdev_release,
+struct vduse_mgmt_dev {
+ struct vdpa_mgmt_dev mgmt_dev;
+ struct device dev;
};

-static struct vdpa_mgmt_dev mgmt_dev;
+static struct vduse_mgmt_dev *vduse_mgmt;

static int vduse_dev_init_vdpa(struct vduse_dev *dev, const char *name)
{
@@ -1509,7 +1505,7 @@ static int vduse_dev_init_vdpa(struct vduse_dev *dev, const char *name)
}
set_dma_ops(&vdev->vdpa.dev, &vduse_dev_dma_ops);
vdev->vdpa.dma_dev = &vdev->vdpa.dev;
- vdev->vdpa.mdev = &mgmt_dev;
+ vdev->vdpa.mdev = &vduse_mgmt->mgmt_dev;

return 0;
}
@@ -1555,34 +1551,52 @@ static struct virtio_device_id id_table[] = {
{ 0 },
};

-static struct vdpa_mgmt_dev mgmt_dev = {
- .device = &vduse_mgmtdev,
- .id_table = id_table,
- .ops = &vdpa_dev_mgmtdev_ops,
-};
+static void vduse_mgmtdev_release(struct device *dev)
+{
+ struct vduse_mgmt_dev *mgmt_dev;
+
+ mgmt_dev = container_of(dev, struct vduse_mgmt_dev, dev);
+ kfree(mgmt_dev);
+}

static int vduse_mgmtdev_init(void)
{
int ret;

- ret = device_register(&vduse_mgmtdev);
- if (ret)
+ vduse_mgmt = kzalloc(sizeof(*vduse_mgmt), GFP_KERNEL);
+ if (!vduse_mgmt)
+ return -ENOMEM;
+
+ ret = dev_set_name(&vduse_mgmt->dev, "vduse");
+ if (ret) {
+ kfree(vduse_mgmt);
return ret;
+ }

- ret = vdpa_mgmtdev_register(&mgmt_dev);
+ vduse_mgmt->dev.release = vduse_mgmtdev_release;
+
+ ret = device_register(&vduse_mgmt->dev);
if (ret)
- goto err;
+ goto dev_reg_err;

- return 0;
-err:
- device_unregister(&vduse_mgmtdev);
+ vduse_mgmt->mgmt_dev.id_table = id_table;
+ vduse_mgmt->mgmt_dev.ops = &vdpa_dev_mgmtdev_ops;
+ vduse_mgmt->mgmt_dev.device = &vduse_mgmt->dev;
+ ret = vdpa_mgmtdev_register(&vduse_mgmt->mgmt_dev);
+ if (ret)
+ device_unregister(&vduse_mgmt->dev);
+
+ return ret;
+
+dev_reg_err:
+ put_device(&vduse_mgmt->dev);
return ret;
}

static void vduse_mgmtdev_exit(void)
{
- vdpa_mgmtdev_unregister(&mgmt_dev);
- device_unregister(&vduse_mgmtdev);
+ vdpa_mgmtdev_unregister(&vduse_mgmt->mgmt_dev);
+ device_unregister(&vduse_mgmt->dev);
}

static int vduse_init(void)
--
2.35.1