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path: root/drivers/misc/mic/scif/scif_peer_bus.c
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Diffstat (limited to 'drivers/misc/mic/scif/scif_peer_bus.c')
-rw-r--r--drivers/misc/mic/scif/scif_peer_bus.c179
1 files changed, 119 insertions, 60 deletions
diff --git a/drivers/misc/mic/scif/scif_peer_bus.c b/drivers/misc/mic/scif/scif_peer_bus.c
index 589ae9ad2501..6ffa3bdbd45b 100644
--- a/drivers/misc/mic/scif/scif_peer_bus.c
+++ b/drivers/misc/mic/scif/scif_peer_bus.c
@@ -24,93 +24,152 @@ dev_to_scif_peer(struct device *dev)
return container_of(dev, struct scif_peer_dev, dev);
}
-static inline struct scif_peer_driver *
-drv_to_scif_peer(struct device_driver *drv)
-{
- return container_of(drv, struct scif_peer_driver, driver);
-}
+struct bus_type scif_peer_bus = {
+ .name = "scif_peer_bus",
+};
-static int scif_peer_dev_match(struct device *dv, struct device_driver *dr)
+static void scif_peer_release_dev(struct device *d)
{
- return !strncmp(dev_name(dv), dr->name, 4);
+ struct scif_peer_dev *sdev = dev_to_scif_peer(d);
+ struct scif_dev *scifdev = &scif_dev[sdev->dnode];
+
+ scif_cleanup_scifdev(scifdev);
+ kfree(sdev);
}
-static int scif_peer_dev_probe(struct device *d)
+static int scif_peer_initialize_device(struct scif_dev *scifdev)
{
- struct scif_peer_dev *dev = dev_to_scif_peer(d);
- struct scif_peer_driver *drv = drv_to_scif_peer(dev->dev.driver);
+ struct scif_peer_dev *spdev;
+ int ret;
- return drv->probe(dev);
-}
+ spdev = kzalloc(sizeof(*spdev), GFP_KERNEL);
+ if (!spdev) {
+ ret = -ENOMEM;
+ goto err;
+ }
-static int scif_peer_dev_remove(struct device *d)
-{
- struct scif_peer_dev *dev = dev_to_scif_peer(d);
- struct scif_peer_driver *drv = drv_to_scif_peer(dev->dev.driver);
+ spdev->dev.parent = scifdev->sdev->dev.parent;
+ spdev->dev.release = scif_peer_release_dev;
+ spdev->dnode = scifdev->node;
+ spdev->dev.bus = &scif_peer_bus;
+ dev_set_name(&spdev->dev, "scif_peer-dev%u", spdev->dnode);
+
+ device_initialize(&spdev->dev);
+ get_device(&spdev->dev);
+ rcu_assign_pointer(scifdev->spdev, spdev);
- drv->remove(dev);
+ mutex_lock(&scif_info.conflock);
+ scif_info.total++;
+ scif_info.maxid = max_t(u32, spdev->dnode, scif_info.maxid);
+ mutex_unlock(&scif_info.conflock);
return 0;
+err:
+ dev_err(&scifdev->sdev->dev,
+ "dnode %d: initialize_device rc %d\n", scifdev->node, ret);
+ return ret;
}
-static struct bus_type scif_peer_bus = {
- .name = "scif_peer_bus",
- .match = scif_peer_dev_match,
- .probe = scif_peer_dev_probe,
- .remove = scif_peer_dev_remove,
-};
-
-int scif_peer_register_driver(struct scif_peer_driver *driver)
+static int scif_peer_add_device(struct scif_dev *scifdev)
{
- driver->driver.bus = &scif_peer_bus;
- return driver_register(&driver->driver);
+ struct scif_peer_dev *spdev = rcu_dereference(scifdev->spdev);
+ char pool_name[16];
+ int ret;
+
+ ret = device_add(&spdev->dev);
+ put_device(&spdev->dev);
+ if (ret) {
+ dev_err(&scifdev->sdev->dev,
+ "dnode %d: peer device_add failed\n", scifdev->node);
+ goto put_spdev;
+ }
+
+ scnprintf(pool_name, sizeof(pool_name), "scif-%d", spdev->dnode);
+ scifdev->signal_pool = dmam_pool_create(pool_name, &scifdev->sdev->dev,
+ sizeof(struct scif_status), 1,
+ 0);
+ if (!scifdev->signal_pool) {
+ dev_err(&scifdev->sdev->dev,
+ "dnode %d: dmam_pool_create failed\n", scifdev->node);
+ ret = -ENOMEM;
+ goto del_spdev;
+ }
+ dev_dbg(&spdev->dev, "Added peer dnode %d\n", spdev->dnode);
+ return 0;
+del_spdev:
+ device_del(&spdev->dev);
+put_spdev:
+ RCU_INIT_POINTER(scifdev->spdev, NULL);
+ synchronize_rcu();
+ put_device(&spdev->dev);
+
+ mutex_lock(&scif_info.conflock);
+ scif_info.total--;
+ mutex_unlock(&scif_info.conflock);
+ return ret;
}
-void scif_peer_unregister_driver(struct scif_peer_driver *driver)
+void scif_add_peer_device(struct work_struct *work)
{
- driver_unregister(&driver->driver);
+ struct scif_dev *scifdev = container_of(work, struct scif_dev,
+ peer_add_work);
+
+ scif_peer_add_device(scifdev);
}
-static void scif_peer_release_dev(struct device *d)
+/*
+ * Peer device registration is split into a device_initialize and a device_add.
+ * The reason for doing this is as follows: First, peer device registration
+ * itself cannot be done in the message processing thread and must be delegated
+ * to another workqueue, otherwise if SCIF client probe, called during peer
+ * device registration, calls scif_connect(..), it will block the message
+ * processing thread causing a deadlock. Next, device_initialize is done in the
+ * "top-half" message processing thread and device_add in the "bottom-half"
+ * workqueue. If this is not done, SCIF_CNCT_REQ message processing executing
+ * concurrently with SCIF_INIT message processing is unable to get a reference
+ * on the peer device, thereby failing the connect request.
+ */
+void scif_peer_register_device(struct scif_dev *scifdev)
{
- struct scif_peer_dev *sdev = dev_to_scif_peer(d);
- struct scif_dev *scifdev = &scif_dev[sdev->dnode];
+ int ret;
- scif_cleanup_scifdev(scifdev);
- kfree(sdev);
+ mutex_lock(&scifdev->lock);
+ ret = scif_peer_initialize_device(scifdev);
+ if (ret)
+ goto exit;
+ schedule_work(&scifdev->peer_add_work);
+exit:
+ mutex_unlock(&scifdev->lock);
}
-struct scif_peer_dev *
-scif_peer_register_device(struct scif_dev *scifdev)
+int scif_peer_unregister_device(struct scif_dev *scifdev)
{
- int ret;
struct scif_peer_dev *spdev;
- spdev = kzalloc(sizeof(*spdev), GFP_KERNEL);
- if (!spdev)
- return ERR_PTR(-ENOMEM);
-
- spdev->dev.parent = scifdev->sdev->dev.parent;
- spdev->dev.release = scif_peer_release_dev;
- spdev->dnode = scifdev->node;
- spdev->dev.bus = &scif_peer_bus;
+ mutex_lock(&scifdev->lock);
+ /* Flush work to ensure device register is complete */
+ flush_work(&scifdev->peer_add_work);
- dev_set_name(&spdev->dev, "scif_peer-dev%u", spdev->dnode);
/*
- * device_register() causes the bus infrastructure to look for a
- * matching driver.
+ * Continue holding scifdev->lock since theoretically unregister_device
+ * can be called simultaneously from multiple threads
*/
- ret = device_register(&spdev->dev);
- if (ret)
- goto free_spdev;
- return spdev;
-free_spdev:
- kfree(spdev);
- return ERR_PTR(ret);
-}
-
-void scif_peer_unregister_device(struct scif_peer_dev *sdev)
-{
- device_unregister(&sdev->dev);
+ spdev = rcu_dereference(scifdev->spdev);
+ if (!spdev) {
+ mutex_unlock(&scifdev->lock);
+ return -ENODEV;
+ }
+
+ RCU_INIT_POINTER(scifdev->spdev, NULL);
+ synchronize_rcu();
+ mutex_unlock(&scifdev->lock);
+
+ dev_dbg(&spdev->dev, "Removing peer dnode %d\n", spdev->dnode);
+ device_unregister(&spdev->dev);
+
+ mutex_lock(&scif_info.conflock);
+ scif_info.total--;
+ mutex_unlock(&scif_info.conflock);
+ return 0;
}
int scif_peer_bus_init(void)