Merge remote-tracking branch 'wsa/i2c/fix-registration' into i2c/i2c-host

Merge Johan Hovold's adapter registration fixes from Wolfram's
branch, addressing races, cleanup paths and resource management
issues.

1 files changed, 100 insertions, 73 deletions

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 7e4b7adffd6e..9224570656d4 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -63,6 +63,7 @@
 static DEFINE_MUTEX(core_lock);
 static DEFINE_IDR(i2c_adapter_idr);
 
+static void i2c_deregister_clients(struct i2c_adapter *adap);
 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
 
 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
@@ -1516,23 +1517,48 @@ int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
 }
 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
 
+static int i2c_allocate_adapter_id(struct i2c_adapter *adap)
+{
+	int id, start, end;
+
+	if (adap->nr == -1) {
+		start = __i2c_first_dynamic_bus_num;
+		end = 0;
+	} else {
+		start = adap->nr;
+		end = adap->nr + 1;
+	}
+
+	mutex_lock(&core_lock);
+	id = idr_alloc(&i2c_adapter_idr, NULL, start, end, GFP_KERNEL);
+	mutex_unlock(&core_lock);
+	if (id < 0) {
+		if (adap->nr != -1 && id == -ENOSPC)
+			id = -EBUSY;
+		pr_err("adapter '%s': failed to allocate id: %d\n", adap->name, id);
+		return id;
+	}
+
+	adap->nr = id;
+
+	return 0;
+}
+
 static int i2c_register_adapter(struct i2c_adapter *adap)
 {
-	int res = -EINVAL;
+	int res;
 
 	/* Can't register until after driver model init */
-	if (WARN_ON(!is_registered)) {
-		res = -EAGAIN;
-		goto out_list;
-	}
+	if (WARN_ON(!is_registered))
+		return -EAGAIN;
 
 	/* Sanity checks */
 	if (WARN(!adap->name[0], "i2c adapter has no name"))
-		goto out_list;
+		return -EINVAL;
 
 	if (!adap->algo) {
 		pr_err("adapter '%s': no algo supplied!\n", adap->name);
-		goto out_list;
+		return -EINVAL;
 	}
 
 	if (!adap->lock_ops)
@@ -1553,14 +1579,25 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	if (res) {
 		pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
 		       adap->name, res);
-		goto out_list;
+		return res;
 	}
 
-	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
+	res = i2c_allocate_adapter_id(adap);
+	if (res)
+		goto err_remove_irq_domain;
+
+	res = dev_set_name(&adap->dev, "i2c-%d", adap->nr);
+	if (res)
+		goto err_free_id;
+
 	adap->dev.bus = &i2c_bus_type;
 	adap->dev.type = &i2c_adapter_type;
 	device_initialize(&adap->dev);
 
+	res = i2c_init_recovery(adap);
+	if (res == -EPROBE_DEFER)
+		goto err_put_adap;
+
 	/*
 	 * This adapter can be used as a parent immediately after device_add(),
 	 * setup runtime-pm (especially ignore-children) before hand.
@@ -1570,22 +1607,21 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	pm_suspend_ignore_children(&adap->dev, true);
 	pm_runtime_enable(&adap->dev);
 
+	adap->debugfs = debugfs_create_dir(dev_name(&adap->dev), i2c_debugfs_root);
+
+	mutex_lock(&core_lock);
+	idr_replace(&i2c_adapter_idr, adap, adap->nr);
+	mutex_unlock(&core_lock);
+
 	res = device_add(&adap->dev);
 	if (res) {
 		pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
-		put_device(&adap->dev);
-		goto out_list;
+		goto err_replace_id;
 	}
 
-	adap->debugfs = debugfs_create_dir(dev_name(&adap->dev), i2c_debugfs_root);
-
 	res = i2c_setup_smbus_alert(adap);
 	if (res)
-		goto out_reg;
-
-	res = i2c_init_recovery(adap);
-	if (res == -EPROBE_DEFER)
-		goto out_reg;
+		goto err_deregister_clients;
 
 	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
 
@@ -1604,36 +1640,27 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 
 	return 0;
 
-out_reg:
+err_deregister_clients:
+	i2c_deregister_clients(adap);
+	device_del(&adap->dev);
+err_replace_id:
+	mutex_lock(&core_lock);
+	idr_replace(&i2c_adapter_idr, NULL, adap->nr);
+	mutex_unlock(&core_lock);
 	debugfs_remove_recursive(adap->debugfs);
+	pm_runtime_disable(&adap->dev);
+err_put_adap:
 	init_completion(&adap->dev_released);
-	device_unregister(&adap->dev);
+	put_device(&adap->dev);
 	wait_for_completion(&adap->dev_released);
-out_list:
+err_free_id:
 	mutex_lock(&core_lock);
 	idr_remove(&i2c_adapter_idr, adap->nr);
 	mutex_unlock(&core_lock);
-	return res;
-}
-
-/**
- * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
- * @adap: the adapter to register (with adap->nr initialized)
- * Context: can sleep
- *
- * See i2c_add_numbered_adapter() for details.
- */
-static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
-{
-	int id;
-
-	mutex_lock(&core_lock);
-	id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
-	mutex_unlock(&core_lock);
-	if (WARN(id < 0, "couldn't get idr"))
-		return id == -ENOSPC ? -EBUSY : id;
+err_remove_irq_domain:
+	i2c_host_notify_irq_teardown(adap);
 
-	return i2c_register_adapter(adap);
+	return res;
 }
 
 /**
@@ -1656,17 +1683,8 @@ int i2c_add_adapter(struct i2c_adapter *adapter)
 	int id;
 
 	id = of_alias_get_id(dev->of_node, "i2c");
-	if (id >= 0) {
-		adapter->nr = id;
-		return __i2c_add_numbered_adapter(adapter);
-	}
-
-	mutex_lock(&core_lock);
-	id = idr_alloc(&i2c_adapter_idr, adapter,
-		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
-	mutex_unlock(&core_lock);
-	if (WARN(id < 0, "couldn't get idr"))
-		return id;
+	if (id < 0)
+		id = -1;
 
 	adapter->nr = id;
 
@@ -1702,7 +1720,7 @@ int i2c_add_numbered_adapter(struct i2c_adapter *adap)
 	if (adap->nr == -1) /* -1 means dynamically assign bus id */
 		return i2c_add_adapter(adap);
 
-	return __i2c_add_numbered_adapter(adap);
+	return i2c_register_adapter(adap);
 }
 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
 
@@ -1744,29 +1762,10 @@ static int __process_removed_adapter(struct device_driver *d, void *data)
 	return 0;
 }
 
-/**
- * i2c_del_adapter - unregister I2C adapter
- * @adap: the adapter being unregistered
- * Context: can sleep
- *
- * This unregisters an I2C adapter which was previously registered
- * by @i2c_add_adapter or @i2c_add_numbered_adapter.
- */
-void i2c_del_adapter(struct i2c_adapter *adap)
+static void i2c_deregister_clients(struct i2c_adapter *adap)
 {
-	struct i2c_adapter *found;
 	struct i2c_client *client, *next;
 
-	/* First make sure that this adapter was ever added */
-	mutex_lock(&core_lock);
-	found = idr_find(&i2c_adapter_idr, adap->nr);
-	mutex_unlock(&core_lock);
-	if (found != adap) {
-		pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
-		return;
-	}
-
-	i2c_acpi_remove_space_handler(adap);
 	/* Tell drivers about this removal */
 	mutex_lock(&core_lock);
 	bus_for_each_drv(&i2c_bus_type, NULL, adap,
@@ -1792,6 +1791,34 @@ void i2c_del_adapter(struct i2c_adapter *adap)
 	 * them up properly, so we give them a chance to do that first. */
 	device_for_each_child(&adap->dev, NULL, __unregister_client);
 	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
+}
+
+/**
+ * i2c_del_adapter - unregister I2C adapter
+ * @adap: the adapter being unregistered
+ * Context: can sleep
+ *
+ * This unregisters an I2C adapter which was previously registered
+ * by @i2c_add_adapter or @i2c_add_numbered_adapter.
+ */
+void i2c_del_adapter(struct i2c_adapter *adap)
+{
+	struct i2c_adapter *found;
+
+	/* First make sure that this adapter was ever added */
+	mutex_lock(&core_lock);
+	found = idr_find(&i2c_adapter_idr, adap->nr);
+	if (found == adap)
+		idr_replace(&i2c_adapter_idr, NULL, adap->nr);
+	mutex_unlock(&core_lock);
+	if (found != adap) {
+		pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
+		return;
+	}
+
+	i2c_acpi_remove_space_handler(adap);
+
+	i2c_deregister_clients(adap);
 
 	/* device name is gone after device_unregister */
 	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);