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From: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To: linux-bluetooth@vger.kernel.org
Subject: [PATCH BlueZ v2 3/3] set: Attempt to use existing set gatt-db
Date: Mon,  3 Jun 2024 14:53:12 -0400
Message-ID: <20240603185312.162337-3-luiz.dentz@gmail.com>
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From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Most sets should be clone of each other, or at least very similar, so
this attempts to clone the existing gatt-db of the first member found
when connecting new sets, this substantially speed up the process of
bonding sets if their database matches which is something that is
currently ranging from 20-30 seconds depending on the manufacturer and
with this changes it cuts 5-10 seconds by bypassing discovery all
procedure of other members.

If the dbs don't really match bt_gatt_client instance will attempt to
rediscover the ranges that don't match.
---
 src/device.c         | 21 +++++++++++++++++++++
 src/device.h         |  1 +
 src/set.c            | 22 ++++++++++++++++++++--
 src/shared/gatt-db.c |  4 ++--
 4 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/src/device.c b/src/device.c
index 620bbd55ebad..5dc1cd0cdbf2 100644
--- a/src/device.c
+++ b/src/device.c
@@ -6994,6 +6994,27 @@ struct gatt_db *btd_device_get_gatt_db(struct btd_device *device)
 	return device->db;
 }
 
+bool btd_device_set_gatt_db(struct btd_device *device, struct gatt_db *db)
+{
+	struct gatt_db *clone;
+
+	if (!device)
+		return false;
+
+	clone = gatt_db_clone(db);
+	if (clone)
+		return false;
+
+	gatt_db_unregister(device->db, device->db_id);
+	gatt_db_unref(device->db);
+
+	device->db = clone;
+	device->db_id = gatt_db_register(device->db, gatt_service_added,
+					gatt_service_removed, device, NULL);
+
+	return true;
+}
+
 struct bt_gatt_client *btd_device_get_gatt_client(struct btd_device *device)
 {
 	if (!device)
diff --git a/src/device.h b/src/device.h
index a2b7bb15d200..0794f92d0178 100644
--- a/src/device.h
+++ b/src/device.h
@@ -66,6 +66,7 @@ struct gatt_primary *btd_device_get_primary(struct btd_device *device,
 							const char *uuid);
 GSList *btd_device_get_primaries(struct btd_device *device);
 struct gatt_db *btd_device_get_gatt_db(struct btd_device *device);
+bool btd_device_set_gatt_db(struct btd_device *device, struct gatt_db *db);
 struct bt_gatt_client *btd_device_get_gatt_client(struct btd_device *device);
 struct bt_gatt_server *btd_device_get_gatt_server(struct btd_device *device);
 bool btd_device_is_initiator(struct btd_device *device);
diff --git a/src/set.c b/src/set.c
index bf35ee403b39..4ca2f78c3702 100644
--- a/src/set.c
+++ b/src/set.c
@@ -28,6 +28,8 @@
 #include "src/shared/queue.h"
 #include "src/shared/ad.h"
 #include "src/shared/crypto.h"
+#include "src/shared/att.h"
+#include "src/shared/gatt-db.h"
 
 #include "log.h"
 #include "error.h"
@@ -277,8 +279,24 @@ static void foreach_rsi(void *data, void *user_data)
 
 	bt_crypto_unref(crypto);
 
-	if (!memcmp(ad->data, res, sizeof(res)))
-		device_connect_le(set->device);
+	if (memcmp(ad->data, res, sizeof(res)))
+		return;
+
+	/* Attempt to use existing gatt_db from set if device has never been
+	 * connected before.
+	 *
+	 * If dbs don't really match bt_gatt_client will attempt to rediscover
+	 * the ranges that don't match.
+	 */
+	if (gatt_db_isempty(btd_device_get_gatt_db(set->device))) {
+		struct btd_device *device;
+
+		device = queue_get_entries(set->devices)->data;
+		btd_device_set_gatt_db(set->device,
+					btd_device_get_gatt_db(device));
+	}
+
+	device_connect_le(set->device);
 }
 
 static void foreach_device(struct btd_device *device, void *data)
diff --git a/src/shared/gatt-db.c b/src/shared/gatt-db.c
index d8d21392fee6..16abcba2ec1c 100644
--- a/src/shared/gatt-db.c
+++ b/src/shared/gatt-db.c
@@ -278,8 +278,8 @@ static void service_clone(void *data, void *user_data)
 	for (i = 0; i < service->num_handles; i++) {
 		struct gatt_db_attribute *attr = service->attributes[i];
 
-		/* Only clone values for characteristics since that is
-		 * cacheable.
+		/* Only clone values for characteristics declaration since that
+		 * is considered when calculating the db hash.
 		 */
 		if (bt_uuid_len(&attr->uuid) == 2 &&
 				attr->uuid.value.u16 == GATT_CHARAC_UUID)
-- 
2.45.1