Hi Johan,
> To avoid too many events being sent to user space and to help parsing of
> all available remote device data it makes sense for us to wait for the
> scan response and send a single merged Device Found event to user space.
>
> This patch adds a few new variables to hci_dev to track the last
> received ADV_IND/ADV_SCAN_IND, i.e. those which will cause a SCAN_REQ to
> be send in the case of active scanning. When the SCAN_RSP is received
> the pending data is passed together with the SCAN_RSP to the
> mgmt_device_found function which takes care of merging them into a
> single Device Found event.
>
> We also need a bit of extra logic to handle situations where we don't
> receive a SCAN_RSP after caching some data. In such a scenario we simply
> have to send out the pending data as it is and then operate on the new
> report as if there was no pending data.
>
> We also need to send out any pending data when scanning stops as
> well as ensure that the storage is empty at the start of a new active
> scanning session. These both cases are covered by the update to the
> hci_cc_le_set_scan_enable function in this patch.
>
> Signed-off-by: Johan Hedberg <johan.hedberg@xxxxxxxxx>
> ---
> include/net/bluetooth/hci_core.h | 4 ++
> net/bluetooth/hci_event.c | 99 +++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 101 insertions(+), 2 deletions(-)
>
> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> index a1b8eab8a47d..59b112397d39 100644
> --- a/include/net/bluetooth/hci_core.h
> +++ b/include/net/bluetooth/hci_core.h
> @@ -68,6 +68,10 @@ struct discovery_state {
> struct list_head unknown; /* Name state not known */
> struct list_head resolve; /* Name needs to be resolved */
> __u32 timestamp;
> + bdaddr_t last_adv_addr;
> + u8 last_adv_addr_type;
> + u8 last_adv_data[HCI_MAX_AD_LENGTH];
> + u8 last_adv_data_len;
> };
>
> struct hci_conn_hash {
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index 4a2c919d5908..b9f0b20c9a51 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -1018,6 +1018,32 @@ static void hci_cc_le_set_scan_param(struct hci_dev *hdev, struct sk_buff *skb)
> hci_dev_unlock(hdev);
> }
>
> +static bool has_pending_adv_report(struct hci_dev *hdev)
> +{
> + struct discovery_state *d = &hdev->discovery;
> +
> + return bacmp(&d->last_adv_addr, BDADDR_ANY);
> +}
> +
> +static void clear_pending_adv_report(struct hci_dev *hdev)
> +{
> + struct discovery_state *d = &hdev->discovery;
> +
> + bacpy(&d->last_adv_addr, BDADDR_ANY);
> + d->last_adv_data_len = 0;
> +}
> +
> +static void store_pending_adv_report(struct hci_dev *hdev, bdaddr_t *bdaddr,
> + u8 bdaddr_type, u8 *data, u8 len)
> +{
> + struct discovery_state *d = &hdev->discovery;
> +
> + bacpy(&d->last_adv_addr, bdaddr);
> + d->last_adv_addr_type = bdaddr_type;
> + memcpy(d->last_adv_data, data, len);
> + d->last_adv_data_len = len;
> +}
> +
> static void hci_cc_le_set_scan_enable(struct hci_dev *hdev,
> struct sk_buff *skb)
> {
> @@ -1036,9 +1062,25 @@ static void hci_cc_le_set_scan_enable(struct hci_dev *hdev,
> switch (cp->enable) {
> case LE_SCAN_ENABLE:
> set_bit(HCI_LE_SCAN, &hdev->dev_flags);
> + if (hdev->le_scan_type == LE_SCAN_ACTIVE)
> + clear_pending_adv_report(hdev);
> break;
>
> case LE_SCAN_DISABLE:
> + /* We do this here instead of when setting DISCOVERY_STOPPED
> + * since the latter would potentially require waiting for
> + * inquiry to stop too.
> + */
> + if (has_pending_adv_report(hdev)) {
> + struct discovery_state *d = &hdev->discovery;
> +
> + mgmt_device_found(hdev, &d->last_adv_addr, LE_LINK,
> + d->last_adv_addr_type, NULL,
> + 0, 0, 1, d->last_adv_data,
> + d->last_adv_data_len,
> + NULL, 0);
indentation is wrong here.
> + }
> +
> /* Cancel this timer so that we don't try to disable scanning
> * when it's already disabled.
> */
> @@ -3964,6 +4006,8 @@ static void check_pending_le_conn(struct hci_dev *hdev, bdaddr_t *addr,
> static void process_adv_report(struct hci_dev *hdev, u8 type, bdaddr_t *bdaddr,
> u8 bdaddr_type, s8 rssi, u8 *data, u8 len)
> {
> + struct discovery_state *d = &hdev->discovery;
> +
> /* Passive scanning shouldn't trigger any device found events */
> if (hdev->le_scan_type == LE_SCAN_PASSIVE) {
> if (type == LE_ADV_IND || type == LE_ADV_DIRECT_IND)
> @@ -3971,8 +4015,59 @@ static void process_adv_report(struct hci_dev *hdev, u8 type, bdaddr_t *bdaddr,
> return;
> }
>
> - mgmt_device_found(hdev, bdaddr, LE_LINK, bdaddr_type, NULL, rssi, 0, 1,
> - data, len, NULL, 0);
> + /* If there's nothing pending either store the data from this
> + * event or send an immediate device found event if the data
> + * should not be stored for later.
> + */
> + if (!has_pending_adv_report(hdev)) {
> + if (type == LE_ADV_IND || type == LE_ADV_SCAN_IND) {
> + store_pending_adv_report(hdev, bdaddr, bdaddr_type,
> + data, len);
> + return;
> + }
> +
> + mgmt_device_found(hdev, bdaddr, LE_LINK, bdaddr_type, NULL,
> + rssi, 0, 1, data, len, NULL, 0);
> + return;
> + }
> +
> + /* If the pending data doesn't match this report or this isn't a
> + * scan response (e.g. we got a duplicate ADV_IND) then force
> + * sending of the pending data.
> + */
> + if (type != LE_ADV_SCAN_RSP || bacmp(bdaddr, &d->last_adv_addr) ||
> + bdaddr_type != d->last_adv_addr_type) {
> + /* Send out whatever is in the cache */
> + mgmt_device_found(hdev, &d->last_adv_addr, LE_LINK,
> + d->last_adv_addr_type, NULL, 0, 0, 1,
> + d->last_adv_data, d->last_adv_data_len,
> + NULL, 0);
> +
> + /* If the new event should be cached store it there */
I can not parse this comment. What to cached store where ;)
> + if (type == LE_ADV_IND || type == LE_ADV_SCAN_IND) {
> + store_pending_adv_report(hdev, bdaddr, bdaddr_type,
> + data, len);
> + return;
> + }
> +
> + /* The event can't be cached so clear the cache and send
> + * an immediate event based on this report.
> + */
The advertising reports can not be merged, so clear the pending report and send out the event. Or something like that.
> + clear_pending_adv_report(hdev);
> + mgmt_device_found(hdev, &d->last_adv_addr, LE_LINK,
> + d->last_adv_addr_type, NULL, rssi, 0, 1,
> + data, len, NULL, 0);
> + return;
> + }
> +
> + /* If we get here we've got a pending ADV_IND or ADV_SCAN_IND and
> + * the new event is a SCAN_RSP. We can therefore proceed with
> + * sending a merged device found event.
> + */
> + mgmt_device_found(hdev, &d->last_adv_addr, LE_LINK,
> + d->last_adv_addr_type, NULL, rssi, 0, 1, data, len,
> + d->last_adv_data, d->last_adv_data_len);
> + clear_pending_adv_report(hdev);
> }
Regards
Marcel
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