Re: [PATCH 2/2] Bluetooth: Remove unneeded commands for suspend

During suspend, there are a few scan enable and set event filter
commands that don't need to be sent unless there are actual BR/EDR
devices capable of waking the system. Check the HCI_PSCAN bit before
writing scan enable and use a new dev flag, HCI_EVENT_FILTER_CONFIGURED
to control whether to clear the event filter.

Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Reviewed-by: Archie Pusaka <redacted>
Reviewed-by: Alain Michaud <redacted>
---

include/net/bluetooth/hci.h |  1 +
net/bluetooth/hci_event.c   | 31 ++++++++++++++++++++++++++
net/bluetooth/hci_request.c | 44 +++++++++++++++++++++++--------------
3 files changed, 59 insertions(+), 17 deletions(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index ba2f439bc04d34..ea4ae551c42687 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h

@@ -320,6 +320,7 @@ enum {

	HCI_BREDR_ENABLED,
	HCI_LE_SCAN_INTERRUPTED,
	HCI_WIDEBAND_SPEECH_ENABLED,
+	HCI_EVENT_FILTER_CONFIGURED,

	HCI_DUT_MODE,
	HCI_VENDOR_DIAG,

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 67668be3461e93..17847e672b98cf 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c

@@ -395,6 +395,33 @@ static void hci_cc_write_scan_enable(struct hci_dev *hdev, struct sk_buff *skb)

	hci_dev_unlock(hdev);
}

+static void hci_cc_set_event_filter(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	__u8 status = *((__u8 *)skb->data);
+	struct hci_cp_set_event_filter *cp;
+	void *sent;
+
+	BT_DBG("%s status 0x%2.2x", hdev->name, status);
+
+	sent = hci_sent_cmd_data(hdev, HCI_OP_SET_EVENT_FLT);
+	if (!sent)
+		return;
+
+	cp = (struct hci_cp_set_event_filter *)sent;
+
+	hci_dev_lock(hdev);
+
+	if (status)
+		goto done;

+
+	if (cp->flt_type == HCI_FLT_CLEAR_ALL)
+		hci_dev_clear_flag(hdev, HCI_EVENT_FILTER_CONFIGURED);
+	else
+		hci_dev_set_flag(hdev, HCI_EVENT_FILTER_CONFIGURED);
+done:
+	hci_dev_unlock(hdev);
+}
+
static void hci_cc_read_class_of_dev(struct hci_dev *hdev, struct sk_buff *skb)
{
	struct hci_rp_read_class_of_dev *rp = (void *) skb->data;

@@ -3328,6 +3355,10 @@ static void hci_cmd_complete_evt(struct hci_dev *hdev, struct sk_buff *skb,

		hci_cc_write_scan_enable(hdev, skb);
		break;

+	case HCI_OP_SET_EVENT_FLT:
+		hci_cc_set_event_filter(hdev, skb);
+		break;
+
	case HCI_OP_READ_CLASS_OF_DEV:
		hci_cc_read_class_of_dev(hdev, skb);
		break;

diff --git a/net/bluetooth/hci_request.c b/net/bluetooth/hci_request.c
index e55976db4403e7..75a42178c82d9b 100644
--- a/net/bluetooth/hci_request.c
+++ b/net/bluetooth/hci_request.c

@@ -1131,14 +1131,14 @@ static void hci_req_clear_event_filter(struct hci_request *req)

{
	struct hci_cp_set_event_filter f;

-	memset(&f, 0, sizeof(f));
-	f.flt_type = HCI_FLT_CLEAR_ALL;
-	hci_req_add(req, HCI_OP_SET_EVENT_FLT, 1, &f);
+	if (!hci_dev_test_flag(req->hdev, HCI_BREDR_ENABLED))
+		return;

-	/* Update page scan state (since we may have modified it when setting
-	 * the event filter).
-	 */
-	__hci_req_update_scan(req);
+	if (hci_dev_test_flag(req->hdev, HCI_EVENT_FILTER_CONFIGURED)) {
+		memset(&f, 0, sizeof(f));
+		f.flt_type = HCI_FLT_CLEAR_ALL;
+		hci_req_add(req, HCI_OP_SET_EVENT_FLT, 1, &f);
+	}
}

static void hci_req_set_event_filter(struct hci_request *req)

@@ -1147,6 +1147,10 @@ static void hci_req_set_event_filter(struct hci_request *req)

	struct hci_cp_set_event_filter f;
	struct hci_dev *hdev = req->hdev;
	u8 scan = SCAN_DISABLED;
+	bool scanning = test_bit(HCI_PSCAN, &hdev->flags);
+
+	if (!hci_dev_test_flag(hdev, HCI_BREDR_ENABLED))
+		return;

	/* Always clear event filter when starting */
	hci_req_clear_event_filter(req);

@@ -1167,12 +1171,13 @@ static void hci_req_set_event_filter(struct hci_request *req)

		scan = SCAN_PAGE;
	}

-	if (scan)
+	if (scan && !scanning) {
		set_bit(SUSPEND_SCAN_ENABLE, hdev->suspend_tasks);
-	else
+		hci_req_add(req, HCI_OP_WRITE_SCAN_ENABLE, 1, &scan);
+	} else if (!scan && scanning) {
		set_bit(SUSPEND_SCAN_DISABLE, hdev->suspend_tasks);
-
-	hci_req_add(req, HCI_OP_WRITE_SCAN_ENABLE, 1, &scan);
+		hci_req_add(req, HCI_OP_WRITE_SCAN_ENABLE, 1, &scan);
+	}
}

static void cancel_adv_timeout(struct hci_dev *hdev)

@@ -1315,9 +1320,14 @@ void hci_req_prepare_suspend(struct hci_dev *hdev, enum suspended_state next)

		hdev->advertising_paused = true;
		hdev->advertising_old_state = old_state;
-		/* Disable page scan */
-		page_scan = SCAN_DISABLED;
-		hci_req_add(&req, HCI_OP_WRITE_SCAN_ENABLE, 1, &page_scan);
+
+		/* Disable page scan if enabled */
+		if (test_bit(HCI_PSCAN, &hdev->flags)) {
+			page_scan = SCAN_DISABLED;
+			hci_req_add(&req, HCI_OP_WRITE_SCAN_ENABLE, 1,
+				    &page_scan);
+			set_bit(SUSPEND_SCAN_DISABLE, hdev->suspend_tasks);
+		}

		/* Disable LE passive scan if enabled */
		if (hci_dev_test_flag(hdev, HCI_LE_SCAN)) {

@@ -1328,9 +1338,6 @@ void hci_req_prepare_suspend(struct hci_dev *hdev, enum suspended_state next)

		/* Disable advertisement filters */
		hci_req_add_set_adv_filter_enable(&req, false);

-		/* Mark task needing completion */
-		set_bit(SUSPEND_SCAN_DISABLE, hdev->suspend_tasks);
-
		/* Prevent disconnects from causing scanning to be re-enabled */
		hdev->scanning_paused = true;

@@ -1364,7 +1371,10 @@ void hci_req_prepare_suspend(struct hci_dev *hdev, enum suspended_state next)

		hdev->suspended = false;
		hdev->scanning_paused = false;

+		/* Clear any event filters and restore scan state */
		hci_req_clear_event_filter(&req);
+		__hci_req_update_scan(&req);
+
		/* Reset passive/background scanning to normal */
		__hci_update_background_scan(&req);
		/* Enable all of the advertisement filters */