vdpa: Extend routine to accept vdpa device name

In a subsequent patch, when user initiated command creates a vdpa device,
the user chooses the name of the vdpa device.
To support it, extend the device allocation API to consider this name
specified by the caller driver.

Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Eli Cohen <elic@nvidia.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210105103203.82508-3-parav@nvidia.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 32 insertions, 4 deletions

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index c0825650c055..7414bbd9057c 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -12,6 +12,8 @@
 #include <linux/slab.h>
 #include <linux/vdpa.h>
 
+/* A global mutex that protects vdpa management device and device level operations. */
+static DEFINE_MUTEX(vdpa_dev_mutex);
 static DEFINE_IDA(vdpa_index_ida);
 
 static int vdpa_dev_probe(struct device *d)
@@ -63,6 +65,7 @@ static void vdpa_release_dev(struct device *d)
  * @config: the bus operations that is supported by this device
  * @nvqs: number of virtqueues supported by this device
  * @size: size of the parent structure that contains private data
+ * @name: name of the vdpa device; optional.
  *
  * Driver should use vdpa_alloc_device() wrapper macro instead of
  * using this directly.
@@ -72,8 +75,7 @@ static void vdpa_release_dev(struct device *d)
  */
 struct vdpa_device *__vdpa_alloc_device(struct device *parent,
 					const struct vdpa_config_ops *config,
-					int nvqs,
-					size_t size)
+					int nvqs, size_t size, const char *name)
 {
 	struct vdpa_device *vdev;
 	int err = -EINVAL;
@@ -101,7 +103,10 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
 	vdev->features_valid = false;
 	vdev->nvqs = nvqs;
 
-	err = dev_set_name(&vdev->dev, "vdpa%u", vdev->index);
+	if (name)
+		err = dev_set_name(&vdev->dev, "%s", name);
+	else
+		err = dev_set_name(&vdev->dev, "vdpa%u", vdev->index);
 	if (err)
 		goto err_name;
 
@@ -118,6 +123,13 @@ err:
 }
 EXPORT_SYMBOL_GPL(__vdpa_alloc_device);
 
+static int vdpa_name_match(struct device *dev, const void *data)
+{
+	struct vdpa_device *vdev = container_of(dev, struct vdpa_device, dev);
+
+	return (strcmp(dev_name(&vdev->dev), data) == 0);
+}
+
 /**
  * vdpa_register_device - register a vDPA device
  * Callers must have a succeed call of vdpa_alloc_device() before.
@@ -127,7 +139,21 @@ EXPORT_SYMBOL_GPL(__vdpa_alloc_device);
  */
 int vdpa_register_device(struct vdpa_device *vdev)
 {
-	return device_add(&vdev->dev);
+	struct device *dev;
+	int err;
+
+	mutex_lock(&vdpa_dev_mutex);
+	dev = bus_find_device(&vdpa_bus, NULL, dev_name(&vdev->dev), vdpa_name_match);
+	if (dev) {
+		put_device(dev);
+		err = -EEXIST;
+		goto name_err;
+	}
+
+	err = device_add(&vdev->dev);
+name_err:
+	mutex_unlock(&vdpa_dev_mutex);
+	return err;
 }
 EXPORT_SYMBOL_GPL(vdpa_register_device);
 
@@ -137,7 +163,9 @@ EXPORT_SYMBOL_GPL(vdpa_register_device);
  */
 void vdpa_unregister_device(struct vdpa_device *vdev)
 {
+	mutex_lock(&vdpa_dev_mutex);
 	device_unregister(&vdev->dev);
+	mutex_unlock(&vdpa_dev_mutex);
 }
 EXPORT_SYMBOL_GPL(vdpa_unregister_device);