Date:   Tue, 14 Feb 2023 15:41:09 -0800
Mime-Version: 1.0
Message-ID: <20230214154104.kernel.v2.1.Ibe4d3a42683381c1e78b8c3aa67b53fc74437ae9@changeid>
Subject: [kernel PATCH v2] Bluetooth: hci_sync: Resume adv with no RPA when
 active scan
From:   Zhengping Jiang <jiangzp@google.com>
To:     linux-bluetooth@vger.kernel.org, marcel@holtmann.org,
        luiz.dentz@gmail.com
Cc:     chromeos-bluetooth-upstreaming@chromium.org,
        Zhengping Jiang <jiangzp@google.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        Paolo Abeni <pabeni@redhat.com>, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

The address resolution should be disabled during the active scan,
so all the advertisements can reach the host. The advertising
has to be paused before disabling the address resolution,
because the advertising will prevent any changes to the resolving
list and the address resolution status. Skipping this will cause
the hci error and the discovery failure.

If the host is using RPA, the controller needs to generate RPA for
the advertising, so the advertising must remain paused during the
active scan.

If the host is not using RPA, the advertising can be resumed after
disabling the address resolution.

Fixes: 9afc675edeeb ("Bluetooth: hci_sync: allow advertise when scan without RPA")
Signed-off-by: Zhengping Jiang <jiangzp@google.com>
---

Changes in v2:
- Commit message format

Changes in v1:
- With LL privacy, always pause advertising when active scan
- Only resume the advertising if the host is not using RPA

 net/bluetooth/hci_sync.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 117eedb6f709..edbf9faf7fa1 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -2402,7 +2402,7 @@ static u8 hci_update_accept_list_sync(struct hci_dev *hdev)
 	u8 filter_policy;
 	int err;
 
-	/* Pause advertising if resolving list can be used as controllers are
+	/* Pause advertising if resolving list can be used as controllers
 	 * cannot accept resolving list modifications while advertising.
 	 */
 	if (use_ll_privacy(hdev)) {
@@ -5397,7 +5397,7 @@ static int hci_active_scan_sync(struct hci_dev *hdev, uint16_t interval)
 	/* Pause advertising since active scanning disables address resolution
 	 * which advertising depend on in order to generate its RPAs.
 	 */
-	if (use_ll_privacy(hdev) && hci_dev_test_flag(hdev, HCI_PRIVACY)) {
+	if (use_ll_privacy(hdev)) {
 		err = hci_pause_advertising_sync(hdev);
 		if (err) {
 			bt_dev_err(hdev, "pause advertising failed: %d", err);
@@ -5416,6 +5416,10 @@ static int hci_active_scan_sync(struct hci_dev *hdev, uint16_t interval)
 		goto failed;
 	}
 
+	// Resume paused advertising if the host is not using RPA
+	if (use_ll_privacy(hdev) && !hci_dev_test_flag(hdev, HCI_PRIVACY))
+		hci_resume_advertising_sync(hdev);
+
 	/* All active scans will be done with either a resolvable private
 	 * address (when privacy feature has been enabled) or non-resolvable
 	 * private address.
-- 
2.39.1.581.gbfd45094c4-goog