diff options
Diffstat (limited to 'drivers/misc/mic/scif/scif_peer_bus.c')
-rw-r--r-- | drivers/misc/mic/scif/scif_peer_bus.c | 165 |
1 files changed, 105 insertions, 60 deletions
diff --git a/drivers/misc/mic/scif/scif_peer_bus.c b/drivers/misc/mic/scif/scif_peer_bus.c index 589ae9a..547bf7b 100644 --- a/drivers/misc/mic/scif/scif_peer_bus.c +++ b/drivers/misc/mic/scif/scif_peer_bus.c @@ -24,93 +24,138 @@ 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); + 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; + } + dev_dbg(&spdev->dev, "Added peer dnode %d\n", spdev->dnode); + return 0; +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) |