[PATCH v10 1/2] Bluetooth: Add le_scan_restart

[PATCH v10 1/2] Bluetooth: Add le_scan_restart

[Jakub Pawlowski]

Currently there is no way to restart le scan, and it's needed in
service scan method. The way it work: it disable, and then enable le
scan on controller.

Signed-off-by: Jakub Pawlowski <jpawlowski@google.com>
---
 include/net/bluetooth/hci_core.h |  3 +++
 net/bluetooth/hci_core.c         | 58 ++++++++++++++++++++++++++++++++++++++++
 net/bluetooth/mgmt.c             |  7 ++++-
 3 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 7777124..de019eb 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -79,6 +79,7 @@ struct discovery_state {
 	s8			rssi;
 	u16			uuid_count;
 	u8			(*uuids)[16];
+	unsigned long		scan_end;
 };
 
 struct hci_conn_hash {
@@ -351,6 +352,7 @@ struct hci_dev {
 	unsigned long		dev_flags;
 
 	struct delayed_work	le_scan_disable;
+	struct delayed_work	le_scan_restart;
 
 	__s8			adv_tx_power;
 	__u8			adv_data[HCI_MAX_AD_LENGTH];
@@ -527,6 +529,7 @@ static inline void hci_discovery_filter_clear(struct hci_dev *hdev)
 	hdev->discovery.uuid_count = 0;
 	kfree(hdev->discovery.uuids);
 	hdev->discovery.uuids = NULL;
+	hdev->discovery.scan_end = 0;
 }
 
 bool hci_discovery_active(struct hci_dev *hdev);
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 34c17a0..478d788 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1614,6 +1614,7 @@ static int hci_dev_do_close(struct hci_dev *hdev)
 		cancel_delayed_work(&hdev->service_cache);
 
 	cancel_delayed_work_sync(&hdev->le_scan_disable);
+	cancel_delayed_work_sync(&hdev->le_scan_restart);
 
 	if (test_bit(HCI_MGMT, &hdev->dev_flags))
 		cancel_delayed_work_sync(&hdev->rpa_expired);
@@ -2790,12 +2791,15 @@ static void le_scan_disable_work_complete(struct hci_dev *hdev, u8 status,
 
 	switch (hdev->discovery.type) {
 	case DISCOV_TYPE_LE:
+		hdev->discovery.scan_end = 0;
 		hci_dev_lock(hdev);
 		hci_discovery_set_state(hdev, DISCOVERY_STOPPED);
 		hci_dev_unlock(hdev);
 		break;
 
 	case DISCOV_TYPE_INTERLEAVED:
+		hdev->discovery.scan_end = 0;
+
 		hci_req_init(&req, hdev);
 
 		memset(&cp, 0, sizeof(cp));
@@ -2827,6 +2831,8 @@ static void le_scan_disable_work(struct work_struct *work)
 
 	BT_DBG("%s", hdev->name);
 
+	cancel_delayed_work_sync(&hdev->le_scan_restart);
+
 	hci_req_init(&req, hdev);
 
 	hci_req_add_le_scan_disable(&req);
@@ -2836,6 +2842,57 @@ static void le_scan_disable_work(struct work_struct *work)
 		BT_ERR("Disable LE scanning request failed: err %d", err);
 }
 
+static void le_scan_restart_work_complete(struct hci_dev *hdev, u8 status,
+					  u16 opcode)
+{
+	long timeout;
+
+	BT_DBG("%s", hdev->name);
+	if (status) {
+		BT_ERR("Failed to restart LE scan: status %d", status);
+		return;
+	}
+
+	if (!test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks) ||
+	    !hdev->discovery.scan_end)
+		return;
+
+	timeout = hdev->discovery.scan_end - jiffies;
+
+	if (timeout < 0)
+		timeout = 0;
+	queue_delayed_work(hdev->workqueue,
+			   &hdev->le_scan_disable, timeout);
+}
+
+static void le_scan_restart_work(struct work_struct *work)
+{
+	struct hci_dev *hdev = container_of(work, struct hci_dev,
+					    le_scan_restart.work);
+	struct hci_request req;
+	struct hci_cp_le_set_scan_enable cp;
+	int err;
+
+	BT_DBG("%s", hdev->name);
+
+	/* If controller is not scanning we are done. */
+	if (!test_bit(HCI_LE_SCAN, &hdev->dev_flags))
+		return;
+
+	hci_req_init(&req, hdev);
+
+	hci_req_add_le_scan_disable(&req);
+
+	memset(&cp, 0, sizeof(cp));
+	cp.enable = LE_SCAN_ENABLE;
+	cp.filter_dup = LE_SCAN_FILTER_DUP_ENABLE;
+	hci_req_add(&req, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(cp), &cp);
+
+	err = hci_req_run(&req, le_scan_restart_work_complete);
+	if (err)
+		BT_ERR("Restart LE scan request failed: err %d", err);
+}
+
 /* Copy the Identity Address of the controller.
  *
  * If the controller has a public BD_ADDR, then by default use that one.
@@ -2931,6 +2988,7 @@ struct hci_dev *hci_alloc_dev(void)
 	INIT_DELAYED_WORK(&hdev->power_off, hci_power_off);
 	INIT_DELAYED_WORK(&hdev->discov_off, hci_discov_off);
 	INIT_DELAYED_WORK(&hdev->le_scan_disable, le_scan_disable_work);
+	INIT_DELAYED_WORK(&hdev->le_scan_restart, le_scan_restart_work);
 
 	skb_queue_head_init(&hdev->rx_q);
 	skb_queue_head_init(&hdev->cmd_q);
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index f5c4d2e..c2b5f8a 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -3878,9 +3878,14 @@ static void start_discovery_complete(struct hci_dev *hdev, u8 status,
 		break;
 	}
 
-	if (timeout)
+	if (timeout) {
+		if (hdev->discovery.uuid_count > 0 &&
+		    test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks))
+			hdev->discovery.scan_end = jiffies + timeout;
+
 		queue_delayed_work(hdev->workqueue,
 				   &hdev->le_scan_disable, timeout);
+	}
 
 unlock:
 	hci_dev_unlock(hdev);
-- 
2.2.0.rc0.207.ga3a616c

[PATCH v10 2/2] Bluetooth: Add restarting to service discovery

[Jakub Pawlowski]

When using LE_SCAN_FILTER_DUP_ENABLE, some controllers would send
advertising report from each LE device only once. That means that we
don't get any updates on RSSI value, and makes Service Discovery very
slow. This patch adds restarting scan when in Service Discovery, and
device with filtered uuid is found, but it's not in RSSI range to send
event yet. This way if device moves into range, we will quickly get RSSI
update.

Signed-off-by: Jakub Pawlowski <jpawlowski@google.com>
---
 include/net/bluetooth/hci_core.h |  1 +
 net/bluetooth/mgmt.c             | 46 +++++++++++++++++++++++++++++++++++++---
 2 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index de019eb..aa5bea0 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -1328,6 +1328,7 @@ void hci_sock_dev_event(struct hci_dev *hdev, int event);
 #define DISCOV_INTERLEAVED_TIMEOUT	5120	/* msec */
 #define DISCOV_INTERLEAVED_INQUIRY_LEN	0x04
 #define DISCOV_BREDR_INQUIRY_LEN	0x08
+#define DISCOV_LE_RESTART_DELAY		msecs_to_jiffies(200)	/* msec */
 
 int mgmt_control(struct sock *sk, struct msghdr *msg, size_t len);
 int mgmt_new_settings(struct hci_dev *hdev);
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index c2b5f8a..67ef0ea 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -7195,6 +7195,20 @@ static bool eir_has_uuids(u8 *eir, u16 eir_len, u16 uuid_count, u8 (*uuids)[16])
 	return false;
 }
 
+static void restart_le_scan(struct hci_dev *hdev)
+{
+	/* If controller is not scanning we are done. */
+	if (!test_bit(HCI_LE_SCAN, &hdev->dev_flags))
+		return;
+
+	if (time_after(jiffies + DISCOV_LE_RESTART_DELAY,
+		       hdev->discovery.scan_end))
+		return;
+
+	queue_delayed_work(hdev->workqueue, &hdev->le_scan_restart,
+			   DISCOV_LE_RESTART_DELAY);
+}
+
 void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
 		       u8 addr_type, u8 *dev_class, s8 rssi, u32 flags,
 		       u8 *eir, u16 eir_len, u8 *scan_rsp, u8 scan_rsp_len)
@@ -7224,7 +7238,9 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
 	 * the results are also dropped.
 	 */
 	if (hdev->discovery.rssi != HCI_RSSI_INVALID &&
-	    (rssi < hdev->discovery.rssi || rssi == HCI_RSSI_INVALID))
+	    (rssi == HCI_RSSI_INVALID ||
+	    (rssi < hdev->discovery.rssi &&
+	     !test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks))))
 		return;
 
 	/* Make sure that the buffer is big enough. The 5 extra bytes
@@ -7258,12 +7274,20 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
 		 * kept and checking possible scan response data
 		 * will be skipped.
 		 */
-		if (hdev->discovery.uuid_count > 0)
+		if (hdev->discovery.uuid_count > 0) {
 			match = eir_has_uuids(eir, eir_len,
 					      hdev->discovery.uuid_count,
 					      hdev->discovery.uuids);
-		else
+			/* we have service match. If duplicate filtering doesn't
+			 * honour RSSI hanges, restart scan to make sure we'll
+			 * get RSSI updates
+			 */
+			if (match && test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER,
+					      &hdev->quirks))
+				restart_le_scan(hdev);
+		} else {
 			match = true;
+		}
 
 		if (!match && !scan_rsp_len)
 			return;
@@ -7296,6 +7320,14 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
 						     hdev->discovery.uuid_count,
 						     hdev->discovery.uuids))
 				return;
+
+			/* we have service match. If duplicate filtering doesn't
+			 * honour RSSI hanges, restart scan to make sure we'll
+			 * get RSSI updates
+			 */
+			if (test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER,
+				     &hdev->quirks))
+				restart_le_scan(hdev);
 		}
 
 		/* Append scan response data to event */
@@ -7309,6 +7341,14 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
 			return;
 	}
 
+	/* Check again wether RSSI value doesn't meet Service Discovery
+	 * threshold. This might evaluate to true only if
+	 * HCI_QUIRK_STRICT_DUPLICATE_FILTER is set.
+	 */
+	if (hdev->discovery.rssi != HCI_RSSI_INVALID &&
+	    rssi < hdev->discovery.rssi)
+		return;
+
 	ev->eir_len = cpu_to_le16(eir_len + scan_rsp_len);
 	ev_size = sizeof(*ev) + eir_len + scan_rsp_len;
 
-- 
2.2.0.rc0.207.ga3a616c

Re: [PATCH v10 1/2] Bluetooth: Add le_scan_restart

[Marcel Holtmann]

Hi Jakub,

I would prefer if the subject is a bit more descriptive in the around 60 characters that you can use.

> Currently there is no way to restart le scan, and it's needed in
> service scan method. The way it work: it disable, and then enable le
> scan on controller.

Please add a bit of detailed description what this is for, why it is used etc.

We expect that complicated changes come with a detailed description in the commit message. In a lot of cases I have seen commit messages that were longer than the actual patch. And that is totally acceptable.

> 
> Signed-off-by: Jakub Pawlowski <jpawlowski@google.com>
> ---
> include/net/bluetooth/hci_core.h |  3 +++
> net/bluetooth/hci_core.c         | 58 ++++++++++++++++++++++++++++++++++++++++
> net/bluetooth/mgmt.c             |  7 ++++-
> 3 files changed, 67 insertions(+), 1 deletion(-)
> 
> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> index 7777124..de019eb 100644
> --- a/include/net/bluetooth/hci_core.h
> +++ b/include/net/bluetooth/hci_core.h
> @@ -79,6 +79,7 @@ struct discovery_state {
> 	s8			rssi;
> 	u16			uuid_count;
> 	u8			(*uuids)[16];
> +	unsigned long		scan_end;
> };
> 
> struct hci_conn_hash {
> @@ -351,6 +352,7 @@ struct hci_dev {
> 	unsigned long		dev_flags;
> 
> 	struct delayed_work	le_scan_disable;
> +	struct delayed_work	le_scan_restart;
> 
> 	__s8			adv_tx_power;
> 	__u8			adv_data[HCI_MAX_AD_LENGTH];
> @@ -527,6 +529,7 @@ static inline void hci_discovery_filter_clear(struct hci_dev *hdev)
> 	hdev->discovery.uuid_count = 0;
> 	kfree(hdev->discovery.uuids);
> 	hdev->discovery.uuids = NULL;
> +	hdev->discovery.scan_end = 0;
> }
> 
> bool hci_discovery_active(struct hci_dev *hdev);
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index 34c17a0..478d788 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -1614,6 +1614,7 @@ static int hci_dev_do_close(struct hci_dev *hdev)
> 		cancel_delayed_work(&hdev->service_cache);
> 
> 	cancel_delayed_work_sync(&hdev->le_scan_disable);
> +	cancel_delayed_work_sync(&hdev->le_scan_restart);
> 
> 	if (test_bit(HCI_MGMT, &hdev->dev_flags))
> 		cancel_delayed_work_sync(&hdev->rpa_expired);
> @@ -2790,12 +2791,15 @@ static void le_scan_disable_work_complete(struct hci_dev *hdev, u8 status,
> 
> 	switch (hdev->discovery.type) {
> 	case DISCOV_TYPE_LE:
> +		hdev->discovery.scan_end = 0;
> 		hci_dev_lock(hdev);
> 		hci_discovery_set_state(hdev, DISCOVERY_STOPPED);
> 		hci_dev_unlock(hdev);
> 		break;
> 
> 	case DISCOV_TYPE_INTERLEAVED:
> +		hdev->discovery.scan_end = 0;
> +

I wonder if it would not be better to just always set it to 0. We are setting the same value in both case statements. So why not just set it before entering the switch statement.

> 		hci_req_init(&req, hdev);
> 
> 		memset(&cp, 0, sizeof(cp));
> @@ -2827,6 +2831,8 @@ static void le_scan_disable_work(struct work_struct *work)
> 
> 	BT_DBG("%s", hdev->name);
> 
> +	cancel_delayed_work_sync(&hdev->le_scan_restart);
> +
> 	hci_req_init(&req, hdev);
> 
> 	hci_req_add_le_scan_disable(&req);
> @@ -2836,6 +2842,57 @@ static void le_scan_disable_work(struct work_struct *work)
> 		BT_ERR("Disable LE scanning request failed: err %d", err);
> }
> 
> +static void le_scan_restart_work_complete(struct hci_dev *hdev, u8 status,
> +					  u16 opcode)
> +{
> +	long timeout;
> +
> +	BT_DBG("%s", hdev->name);

Extra empty line here.

> +	if (status) {
> +		BT_ERR("Failed to restart LE scan: status %d", status);
> +		return;
> +	}
> +
> +	if (!test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks) ||
> +	    !hdev->discovery.scan_end)
> +		return;
> +
> +	timeout = hdev->discovery.scan_end - jiffies;
> +

No empty line here.

> +	if (timeout < 0)
> +		timeout = 0;

Since jiffies can wrap around, are we taking that into account.

> +	queue_delayed_work(hdev->workqueue,
> +			   &hdev->le_scan_disable, timeout);

This function takes an unsigned long timeout. So I wonder if we not better use timing helper function to calculate the right timeout value. We really want to terminate the LE scanning on time and not 20 years in the future.

> +}
> +
> +static void le_scan_restart_work(struct work_struct *work)
> +{
> +	struct hci_dev *hdev = container_of(work, struct hci_dev,
> +					    le_scan_restart.work);
> +	struct hci_request req;
> +	struct hci_cp_le_set_scan_enable cp;
> +	int err;
> +
> +	BT_DBG("%s", hdev->name);
> +
> +	/* If controller is not scanning we are done. */
> +	if (!test_bit(HCI_LE_SCAN, &hdev->dev_flags))
> +		return;
> +
> +	hci_req_init(&req, hdev);
> +
> +	hci_req_add_le_scan_disable(&req);
> +
> +	memset(&cp, 0, sizeof(cp));
> +	cp.enable = LE_SCAN_ENABLE;
> +	cp.filter_dup = LE_SCAN_FILTER_DUP_ENABLE;
> +	hci_req_add(&req, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(cp), &cp);
> +
> +	err = hci_req_run(&req, le_scan_restart_work_complete);
> +	if (err)
> +		BT_ERR("Restart LE scan request failed: err %d", err);
> +}
> +
> /* Copy the Identity Address of the controller.
>  *
>  * If the controller has a public BD_ADDR, then by default use that one.
> @@ -2931,6 +2988,7 @@ struct hci_dev *hci_alloc_dev(void)
> 	INIT_DELAYED_WORK(&hdev->power_off, hci_power_off);
> 	INIT_DELAYED_WORK(&hdev->discov_off, hci_discov_off);
> 	INIT_DELAYED_WORK(&hdev->le_scan_disable, le_scan_disable_work);
> +	INIT_DELAYED_WORK(&hdev->le_scan_restart, le_scan_restart_work);
> 
> 	skb_queue_head_init(&hdev->rx_q);
> 	skb_queue_head_init(&hdev->cmd_q);
> diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
> index f5c4d2e..c2b5f8a 100644
> --- a/net/bluetooth/mgmt.c
> +++ b/net/bluetooth/mgmt.c
> @@ -3878,9 +3878,14 @@ static void start_discovery_complete(struct hci_dev *hdev, u8 status,
> 		break;
> 	}
> 
> -	if (timeout)
> +	if (timeout) {
> +		if (hdev->discovery.uuid_count > 0 &&

I would check for the quirk first. That is the important one. In addition this should also check if a RSSI threshold is provided. Since you can have no UUID listed, but want to see devices fall below a certain RSSI threshold.

> +		    test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks))
> +			hdev->discovery.scan_end = jiffies + timeout;
> +
> 		queue_delayed_work(hdev->workqueue,
> 				   &hdev->le_scan_disable, timeout);
> +	}
> 
> unlock:
> 	hci_dev_unlock(hdev);

Regards

Marcel

Re: [PATCH v10 2/2] Bluetooth: Add restarting to service discovery

[Marcel Holtmann]

Hi Jakub,

> When using LE_SCAN_FILTER_DUP_ENABLE, some controllers would send
> advertising report from each LE device only once. That means that we
> don't get any updates on RSSI value, and makes Service Discovery very
> slow. This patch adds restarting scan when in Service Discovery, and
> device with filtered uuid is found, but it's not in RSSI range to send
> event yet. This way if device moves into range, we will quickly get RSSI
> update.
> 
> Signed-off-by: Jakub Pawlowski <jpawlowski@google.com>
> ---
> include/net/bluetooth/hci_core.h |  1 +
> net/bluetooth/mgmt.c             | 46 +++++++++++++++++++++++++++++++++++++---
> 2 files changed, 44 insertions(+), 3 deletions(-)
> 
> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> index de019eb..aa5bea0 100644
> --- a/include/net/bluetooth/hci_core.h
> +++ b/include/net/bluetooth/hci_core.h
> @@ -1328,6 +1328,7 @@ void hci_sock_dev_event(struct hci_dev *hdev, int event);
> #define DISCOV_INTERLEAVED_TIMEOUT	5120	/* msec */
> #define DISCOV_INTERLEAVED_INQUIRY_LEN	0x04
> #define DISCOV_BREDR_INQUIRY_LEN	0x08
> +#define DISCOV_LE_RESTART_DELAY		msecs_to_jiffies(200)	/* msec */
> 
> int mgmt_control(struct sock *sk, struct msghdr *msg, size_t len);
> int mgmt_new_settings(struct hci_dev *hdev);
> diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
> index c2b5f8a..67ef0ea 100644
> --- a/net/bluetooth/mgmt.c
> +++ b/net/bluetooth/mgmt.c
> @@ -7195,6 +7195,20 @@ static bool eir_has_uuids(u8 *eir, u16 eir_len, u16 uuid_count, u8 (*uuids)[16])
> 	return false;
> }
> 
> +static void restart_le_scan(struct hci_dev *hdev)
> +{
> +	/* If controller is not scanning we are done. */
> +	if (!test_bit(HCI_LE_SCAN, &hdev->dev_flags))
> +		return;
> +
> +	if (time_after(jiffies + DISCOV_LE_RESTART_DELAY,
> +		       hdev->discovery.scan_end))
> +		return;
> +
> +	queue_delayed_work(hdev->workqueue, &hdev->le_scan_restart,
> +			   DISCOV_LE_RESTART_DELAY);
> +}
> +
> void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
> 		       u8 addr_type, u8 *dev_class, s8 rssi, u32 flags,
> 		       u8 *eir, u16 eir_len, u8 *scan_rsp, u8 scan_rsp_len)
> @@ -7224,7 +7238,9 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
> 	 * the results are also dropped.
> 	 */
> 	if (hdev->discovery.rssi != HCI_RSSI_INVALID &&
> -	    (rssi < hdev->discovery.rssi || rssi == HCI_RSSI_INVALID))
> +	    (rssi == HCI_RSSI_INVALID ||
> +	    (rssi < hdev->discovery.rssi &&
> +	     !test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks))))
> 		return;

there is a comment above this if clause. So that one needs to be adjusted to take this new case into account.

> 	/* Make sure that the buffer is big enough. The 5 extra bytes
> @@ -7258,12 +7274,20 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
> 		 * kept and checking possible scan response data
> 		 * will be skipped.
> 		 */
> -		if (hdev->discovery.uuid_count > 0)
> +		if (hdev->discovery.uuid_count > 0) {
> 			match = eir_has_uuids(eir, eir_len,
> 					      hdev->discovery.uuid_count,
> 					      hdev->discovery.uuids);
> -		else
> +			/* we have service match. If duplicate filtering doesn't
> +			 * honour RSSI hanges, restart scan to make sure we'll
> +			 * get RSSI updates
> +			 */

Lets fix the spelling here first. Also skip the "we have service match". That is just something out of context and hard to read.

			/* If duplicate filtering does not report RSSI changes, then
			 * restart scanning to ensure updated result with updated
			 * RSSI values.
			 */

> +			if (match && test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER,
> +					      &hdev->quirks))
> +				restart_le_scan(hdev);
> +		} else {
> 			match = true;
> +		}
> 
> 		if (!match && !scan_rsp_len)
> 			return;
> @@ -7296,6 +7320,14 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
> 						     hdev->discovery.uuid_count,
> 						     hdev->discovery.uuids))
> 				return;
> +
> +			/* we have service match. If duplicate filtering doesn't
> +			 * honour RSSI hanges, restart scan to make sure we'll
> +			 * get RSSI updates
> +			 */

Same here.

> +			if (test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER,
> +				     &hdev->quirks))

This really do not fit into a single line?

> +				restart_le_scan(hdev);
> 		}
> 
> 		/* Append scan response data to event */
> @@ -7309,6 +7341,14 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
> 			return;
> 	}
> 
> +	/* Check again wether RSSI value doesn't meet Service Discovery
> +	 * threshold. This might evaluate to true only if
> +	 * HCI_QUIRK_STRICT_DUPLICATE_FILTER is set.
> +	 */

	/* Validate the reported RSSI value against the RSSI threshold once more in
	 * case HCI_QUIRK_STRICT_DUPLICATE_FILTER forced a restart of LE scanning.
	 */

> +	if (hdev->discovery.rssi != HCI_RSSI_INVALID &&
> +	    rssi < hdev->discovery.rssi)
> +		return;
> +
> 	ev->eir_len = cpu_to_le16(eir_len + scan_rsp_len);
> 	ev_size = sizeof(*ev) + eir_len + scan_rsp_len;

Regards

Marcel