[PATCH v3] bluetooth: Add reference count for bluetooth utils

[PATCH v3] bluetooth: Add reference count for bluetooth utils

[=?unknown-8bit?q?Fr=C3=A9d=C3=A9ric?= Danis]

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Add bluetooth_ref()/bluetooth_unref() to support reference count in
bluetooth utils.
---
 plugins/bluetooth.c |   59 ++++++++++++++++++++++++++++++++++++++-------------
 1 files changed, 44 insertions(+), 15 deletions(-)

diff --git a/plugins/bluetooth.c b/plugins/bluetooth.c
index 602c6da..8202381 100644
--- a/plugins/bluetooth.c
+++ b/plugins/bluetooth.c
@@ -40,6 +40,7 @@
 static DBusConnection *connection;
 static GHashTable *uuid_hash = NULL;
 static GHashTable *adapter_address_hash = NULL;
+static gint ref_count;
 
 void bluetooth_create_path(const char *dev_addr, const char *adapter_addr,
 				char *buf, int size)
@@ -504,12 +505,12 @@ static guint adapter_added_watch;
 static guint adapter_removed_watch;
 static guint property_watch;
 
-int bluetooth_register_uuid(const char *uuid, struct bluetooth_profile *profile)
+static int bluetooth_ref(void)
 {
 	int err;
 
-	if (uuid_hash)
-		goto done;
+	if (ref_count > 0)
+		return 0;
 
 	connection = ofono_dbus_get_connection();
 
@@ -543,12 +544,7 @@ int bluetooth_register_uuid(const char *uuid, struct bluetooth_profile *profile)
 	adapter_address_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 						g_free, g_free);
 
-done:
-	g_hash_table_insert(uuid_hash, g_strdup(uuid), profile);
-
-	bluetooth_send_with_reply("/", BLUEZ_MANAGER_INTERFACE, "GetProperties",
-				manager_properties_cb, NULL, NULL, -1,
-				DBUS_TYPE_INVALID);
+	g_atomic_int_inc(&ref_count);
 
 	return 0;
 
@@ -560,11 +556,13 @@ remove:
 	return err;
 }
 
-void bluetooth_unregister_uuid(const char *uuid)
+static void bluetooth_unref(void)
 {
-	g_hash_table_remove(uuid_hash, uuid);
+	gboolean is_zero;
+
+	is_zero = g_atomic_int_dec_and_test(&ref_count);
 
-	if (g_hash_table_size(uuid_hash))
+	if (is_zero == FALSE)
 		return;
 
 	g_dbus_remove_watch(connection, bluetooth_watch);
@@ -572,9 +570,40 @@ void bluetooth_unregister_uuid(const char *uuid)
 	g_dbus_remove_watch(connection, adapter_removed_watch);
 	g_dbus_remove_watch(connection, property_watch);
 
-	g_hash_table_destroy(uuid_hash);
-	g_hash_table_destroy(adapter_address_hash);
-	uuid_hash = NULL;
+	if (uuid_hash) {
+		g_hash_table_destroy(uuid_hash);
+		uuid_hash = NULL;
+	}
+
+	if (adapter_address_hash) {
+		g_hash_table_destroy(adapter_address_hash);
+		adapter_address_hash = NULL;
+	}
+}
+
+int bluetooth_register_uuid(const char *uuid, struct bluetooth_profile *profile)
+{
+	int err;
+
+	err = bluetooth_ref();
+
+	if (err != 0)
+		return err;
+
+	g_hash_table_insert(uuid_hash, g_strdup(uuid), profile);
+
+	bluetooth_send_with_reply("/", BLUEZ_MANAGER_INTERFACE, "GetProperties",
+				manager_properties_cb, NULL, NULL, -1,
+				DBUS_TYPE_INVALID);
+
+	return 0;
+}
+
+void bluetooth_unregister_uuid(const char *uuid)
+{
+	g_hash_table_remove(uuid_hash, uuid);
+
+	bluetooth_unref();
 }
 
 OFONO_PLUGIN_DEFINE(bluetooth, "Bluetooth Utils Plugins", VERSION,
-- 
1.7.1

Re: [PATCH v3] bluetooth: Add reference count for bluetooth utils

[Gustavo F. Padovan]

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* Frédéric Danis <frederic.danis@linux.intel.com> [2011-01-19 12:17:51 +0100]:

> Add bluetooth_ref()/bluetooth_unref() to support reference count in
> bluetooth utils.
> ---
>  plugins/bluetooth.c |   59 ++++++++++++++++++++++++++++++++++++++-------------
>  1 files changed, 44 insertions(+), 15 deletions(-)

Acked.

-- 
Gustavo F. Padovan
http://profusion.mobi

Re: [PATCH v3] bluetooth: Add reference count for bluetooth utils

[Marcel Holtmann]

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Hi Fred,

> diff --git a/plugins/bluetooth.c b/plugins/bluetooth.c
> index 602c6da..8202381 100644
> --- a/plugins/bluetooth.c
> +++ b/plugins/bluetooth.c
> @@ -40,6 +40,7 @@
>  static DBusConnection *connection;
>  static GHashTable *uuid_hash = NULL;
>  static GHashTable *adapter_address_hash = NULL;
> +static gint ref_count;

you need a better name for this. This is too generic. Maybe using
bluetooth_refcount is better.

>  void bluetooth_create_path(const char *dev_addr, const char *adapter_addr,
>  				char *buf, int size)
> @@ -504,12 +505,12 @@ static guint adapter_added_watch;
>  static guint adapter_removed_watch;
>  static guint property_watch;
>  
> -int bluetooth_register_uuid(const char *uuid, struct bluetooth_profile *profile)
> +static int bluetooth_ref(void)
>  {
>  	int err;
>  
> -	if (uuid_hash)
> -		goto done;
> +	if (ref_count > 0)
> +		return 0;

This is pretty much wrong. A reference count can't work this way. You
need to track the number of times this has been taken.

	g_atomic_int_inc(&bluetooth_refcount);

	if (bluetooth_refcount > 1)
		return 0;

In addition, I think the return value is pointless, just make sure to
decrease the reference count in an error case.

> +static void bluetooth_unref(void)
>  {
> -	g_hash_table_remove(uuid_hash, uuid);
> +	gboolean is_zero;
> +
> +	is_zero = g_atomic_int_dec_and_test(&ref_count);
>  
> -	if (g_hash_table_size(uuid_hash))
> +	if (is_zero == FALSE)
>  		return;

I know that we have it like this in GAtChat, but just do the check right
away is fine.

	if (g_atomic_int_dec_and_test(&bluetooth_refcount) == FALSE)
		return;

Regards

Marcel