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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To:     linux-bluetooth@vger.kernel.org
Subject: [PATCH BlueZ 2/4] shared/gatt-client: Allow registering with NULL callback
Date:   Thu,  5 Jan 2023 14:09:42 -0800
Message-Id: <20230105220944.2373424-2-luiz.dentz@gmail.com>
In-Reply-To: <20230105220944.2373424-1-luiz.dentz@gmail.com>
References: <20230105220944.2373424-1-luiz.dentz@gmail.com>
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From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This makes bt_gatt_client_register_notify allow registering with NULL
callback which is interpreted as the CCC write has already been
performed therefore it won't be written again.
---
 src/shared/gatt-client.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/shared/gatt-client.c b/src/shared/gatt-client.c
index 4aa5d7d92957..593b0f27f871 100644
--- a/src/shared/gatt-client.c
+++ b/src/shared/gatt-client.c
@@ -1711,8 +1711,11 @@ static unsigned int register_notify(struct bt_gatt_client *client,
 		 * descriptor.
 		 */
 		chrc = notify_chrc_create(client, handle);
-		if (!chrc)
+		if (!chrc) {
+			DBG(client, "Unable to locate characteristic at 0x%04x",
+							handle);
 			return 0;
+		}
 	}
 
 	/* Fail if we've hit the maximum allowed notify sessions */
@@ -1750,9 +1753,10 @@ static unsigned int register_notify(struct bt_gatt_client *client,
 	}
 
 	/*
-	 * If the ref count > 1, then notifications are already enabled.
+	 * If the ref count > 1, ccc handle cannot be found or registration
+	 * callback is not set consider notifications are already enabled.
 	 */
-	if (chrc->notify_count > 1 || !chrc->ccc_handle) {
+	if (chrc->notify_count > 1 || !chrc->ccc_handle || !callback) {
 		complete_notify_request(notify_data);
 		return notify_data->id;
 	}
@@ -2176,6 +2180,9 @@ static void notify_cb(struct bt_att_chan *chan, uint8_t opcode,
 	struct bt_gatt_client *client = user_data;
 	struct value_data data;
 
+	if (queue_isempty(client->notify_list))
+		return;
+
 	bt_gatt_client_ref(client);
 
 	memset(&data, 0, sizeof(data));
@@ -3670,7 +3677,8 @@ unsigned int bt_gatt_client_register_notify(struct bt_gatt_client *client,
 				void *user_data,
 				bt_gatt_client_destroy_func_t destroy)
 {
-	if (!client || !client->db || !chrc_value_handle || !callback)
+	if (!client || !client->db || !chrc_value_handle ||
+				(!callback && !notify))
 		return 0;
 
 	if (client->in_svc_chngd)
-- 
2.37.3