linux-kernel - [kernel PATCH v1 1/1] Bluetooth: Don't send HCI commands to remove adv if adapter is off

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Date:   Wed, 25 Jan 2023 13:12:10 -0800
From:   Zhengping Jiang <jiangzp@...gle.com>
To:     linux-bluetooth@...r.kernel.org, marcel@...tmann.org,
        luiz.dentz@...il.com
Cc:     chromeos-bluetooth-upstreaming@...omium.org,
        Archie Pusaka <apusaka@...omium.org>,
        Zhengping Jiang <jiangzp@...gle.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Paolo Abeni <pabeni@...hat.com>, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org
Subject: [kernel PATCH v1 1/1] Bluetooth: Don't send HCI commands to remove
 adv if adapter is off

From: Archie Pusaka <apusaka@...omium.org>

Mark the advertisement as disabled when powering off the adapter
without removing the advertisement, so they can be correctly
re-enabled when adapter is powered on again.

When adapter is off and user requested to remove advertisement,
a HCI command will be issued. This causes the command to timeout
and trigger GPIO reset.

Therefore, immediately remove the advertisement without sending
any HCI commands.

Note that the above scenario only happens with extended advertisement
(i.e. not using software rotation), because on the SW rotation
scenario, we just wait until the rotation timer runs out before
sending the HCI command. Since the timer is inactive when adapter is
off, no HCI commands are sent.

Signed-off-by: Archie Pusaka <apusaka@...omium.org>
Signed-off-by: Zhengping Jiang <jiangzp@...gle.com>

---

Changes in v1:
- Mark the advertisement as disabled instead of clearing it.
- Remove the advertisement without sending HCI command if the adapter is off.

 net/bluetooth/hci_sync.c | 57 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 53 insertions(+), 4 deletions(-)

diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 117eedb6f709..08da68a30acc 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -1591,6 +1591,16 @@ int hci_remove_ext_adv_instance_sync(struct hci_dev *hdev, u8 instance,
 	if (!ext_adv_capable(hdev))
 		return 0;
 
+	/* When adapter is off, remove adv without sending HCI commands */
+	if (!hdev_is_powered(hdev)) {
+		hci_dev_lock(hdev);
+		err = hci_remove_adv_instance(hdev, instance);
+		if (!err)
+			mgmt_advertising_removed(sk, hdev, instance);
+		hci_dev_unlock(hdev);
+		return err;
+	}
+
 	err = hci_disable_ext_adv_instance_sync(hdev, instance);
 	if (err)
 		return err;
@@ -1772,6 +1782,23 @@ int hci_schedule_adv_instance_sync(struct hci_dev *hdev, u8 instance,
 	return hci_start_adv_sync(hdev, instance);
 }
 
+static void hci_clear_ext_adv_ins_during_power_off(struct hci_dev *hdev,
+						   struct sock *sk)
+{
+	struct adv_info *adv, *n;
+	int err;
+
+	hci_dev_lock(hdev);
+	list_for_each_entry_safe(adv, n, &hdev->adv_instances, list) {
+		u8 instance = adv->instance;
+
+		err = hci_remove_adv_instance(hdev, instance);
+		if (!err)
+			mgmt_advertising_removed(sk, hdev, instance);
+	}
+	hci_dev_unlock(hdev);
+}
+
 static int hci_clear_adv_sets_sync(struct hci_dev *hdev, struct sock *sk)
 {
 	int err;
@@ -1779,6 +1806,12 @@ static int hci_clear_adv_sets_sync(struct hci_dev *hdev, struct sock *sk)
 	if (!ext_adv_capable(hdev))
 		return 0;
 
+	/* When adapter is off, remove adv without sending HCI commands */
+	if (!hdev_is_powered(hdev)) {
+		hci_clear_ext_adv_ins_during_power_off(hdev, sk);
+		return 0;
+	}
+
 	/* Disable instance 0x00 to disable all instances */
 	err = hci_disable_ext_adv_instance_sync(hdev, 0x00);
 	if (err)
@@ -5177,9 +5210,27 @@ static int hci_disconnect_all_sync(struct hci_dev *hdev, u8 reason)
 	return 0;
 }
 
+static void hci_disable_ext_advertising_temporarily(struct hci_dev *hdev)
+{
+	struct adv_info *adv, *n;
+
+	if (!ext_adv_capable(hdev))
+		return;
+
+	hci_dev_lock(hdev);
+
+	list_for_each_entry_safe(adv, n, &hdev->adv_instances, list)
+		adv->enabled = false;
+
+	hci_dev_clear_flag(hdev, HCI_LE_ADV);
+
+	hci_dev_unlock(hdev);
+}
+
 /* This function perform power off HCI command sequence as follows:
  *
- * Clear Advertising
+ * Disable Advertising Instances. Do not clear adv instances so advertising
+ * can be re-enabled on power on.
  * Stop Discovery
  * Disconnect all connections
  * hci_dev_close_sync
@@ -5199,9 +5250,7 @@ static int hci_power_off_sync(struct hci_dev *hdev)
 			return err;
 	}
 
-	err = hci_clear_adv_sync(hdev, NULL, false);
-	if (err)
-		return err;
+	hci_disable_ext_advertising_temporarily(hdev);
 
 	err = hci_stop_discovery_sync(hdev);
 	if (err)
-- 
2.39.1.456.gfc5497dd1b-goog