Hi Briglia,
* Anderson Briglia <anderson.briglia@xxxxxxxxxxxxx> [2011-08-03 15:09:50 -0400]:
> Hi Padovan,
>
> On Wed, Aug 3, 2011 at 2:48 PM, Gustavo Padovan <padovan@xxxxxxxxxxxxxx> wrote:
> > Hi Briglia,
> >
> > * Anderson Briglia <anderson.briglia@xxxxxxxxxxxxx> [2011-08-02 14:35:08 -0400]:
> >
> >> This is the polling mechanism to send HCI Read RSSI commands. The
> >> command responses are used by the RSSI Monitor to get the current RSSI
> >> value and calculate the current alert level for a given monitored
> >> connection.
> >>
> >> This patch also adds read and write locks on rssi_monitor_list in
> >> order to avoid race conditions.
> >>
> >> Signed-off-by: Anderson Briglia <anderson.briglia@xxxxxxxxxxxxx>
> >> ---
> >> include/net/bluetooth/hci_core.h | 3 +
> >> net/bluetooth/hci_core.c | 12 +++++
> >> net/bluetooth/mgmt.c | 99 ++++++++++++++++++++++++++++++++++----
> >> 3 files changed, 104 insertions(+), 10 deletions(-)
> >>
> >> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> >> index a3cf433..8ff3448 100644
> >> --- a/include/net/bluetooth/hci_core.h
> >> +++ b/include/net/bluetooth/hci_core.h
> >> @@ -211,6 +211,8 @@ struct hci_dev {
> >>
> >> struct timer_list le_scan_timer;
> >>
> >> + struct timer_list rssi_monitor_timer;
> >
> > call this rssi_timer is enough.
> >
> >> +
> >> struct hci_dev_stats stat;
> >>
> >> struct sk_buff_head driver_init;
> >> @@ -869,6 +871,7 @@ int mgmt_has_pending_stop_discov(u16 index);
> >> int mgmt_cancel_discovery(u16 index);
> >> int mgmt_is_interleaved_discovery(u16 index);
> >> int mgmt_do_interleaved_discovery(u16 index);
> >> +void mgmt_do_read_rssi(struct hci_dev *hdev);
> >>
> >> /* HCI info for socket */
> >> #define hci_pi(sk) ((struct hci_pinfo *) sk)
> >> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> >> index c0c46bf..eb51b94 100644
> >> --- a/net/bluetooth/hci_core.c
> >> +++ b/net/bluetooth/hci_core.c
> >> @@ -1449,6 +1449,14 @@ static void hci_disable_le_scan(unsigned long arg)
> >> hci_send_cmd(hdev, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(cp), &cp);
> >> }
> >>
> >> +static void hci_do_read_rssi(unsigned long arg)
> >> +{
> >> + struct hci_dev *hdev = (void *) arg;
> >> +
> >> + if (test_bit(HCI_UP, &hdev->flags))
> >> + mgmt_do_read_rssi(hdev);
> >> +}
> >> +
> >> /* Register HCI device */
> >> int hci_register_dev(struct hci_dev *hdev)
> >> {
> >> @@ -1522,6 +1530,9 @@ int hci_register_dev(struct hci_dev *hdev)
> >> setup_timer(&hdev->le_scan_timer, hci_disable_le_scan,
> >> (unsigned long) hdev);
> >>
> >> + setup_timer(&hdev->rssi_monitor_timer, hci_do_read_rssi,
> >> + (unsigned long) hdev);
> >> +
> >> INIT_WORK(&hdev->power_on, hci_power_on);
> >> INIT_WORK(&hdev->power_off, hci_power_off);
> >> setup_timer(&hdev->off_timer, hci_auto_off, (unsigned long) hdev);
> >> @@ -1604,6 +1615,7 @@ int hci_unregister_dev(struct hci_dev *hdev)
> >> hci_del_off_timer(hdev);
> >> del_timer(&hdev->adv_timer);
> >> del_timer(&hdev->le_scan_timer);
> >> + del_timer(&hdev->rssi_monitor_timer);
> >>
> >> destroy_workqueue(hdev->workqueue);
> >>
> >> diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
> >> index 65ddbff..b034290 100644
> >> --- a/net/bluetooth/mgmt.c
> >> +++ b/net/bluetooth/mgmt.c
> >> @@ -48,6 +48,8 @@ enum bt_device_type {
> >> #define RSSI_MONITOR_ALERT_LOW 0x01
> >> #define RSSI_MONITOR_ALERT_HIGH 0x02
> >>
> >> +#define RSSI_MONITOR_TIMEOUT 2000
> >> +
> >> struct pending_cmd {
> >> struct list_head list;
> >> __u16 opcode;
> >> @@ -70,6 +72,9 @@ struct rssi_monitor {
> >>
> >> static LIST_HEAD(rssi_monitor_list);
> >>
> >> +static rwlock_t rssi_monitor_list_lock;
> >> +static DEFINE_RWLOCK(rssi_monitor_list_lock);
> >
> > Use a normal spinlock here.
>
> Ok.
> >
> >> +
> >> static int cmd_status(struct sock *sk, u16 index, u16 cmd, u8 status)
> >> {
> >> struct sk_buff *skb;
> >> @@ -1916,21 +1921,46 @@ static struct rssi_monitor *rssi_monitor_find(u16 index, bdaddr_t *bdaddr)
> >> return NULL;
> >> }
> >>
> >> +static void rssi_monitor_start(u16 index)
> >> +{
> >> + struct hci_dev *hdev;
> >> +
> >> + if (list_empty(&rssi_monitor_list))
> >> + return;
> >> +
> >> + hdev = hci_dev_get(index);
> >> + if (!hdev)
> >> + return;
> >> +
> >> + mod_timer(&hdev->rssi_monitor_timer, jiffies +
> >> + msecs_to_jiffies(RSSI_MONITOR_TIMEOUT));
> >> + hci_dev_put(hdev);
> >> +}
> >> +
> >> static int rssi_monitor_add(u16 index, bdaddr_t *bdaddr, s8 low_trigger,
> >> s8 high_trigger)
> >> {
> >> struct rssi_monitor *rm;
> >> + int err = 0;
> >>
> >> - if (rssi_monitor_find(index, bdaddr))
> >> - return -EEXIST;
> >> + write_lock_bh(&rssi_monitor_list_lock);
> >> +
> >> + if (rssi_monitor_find(index, bdaddr)) {
> >> + err = -EEXIST;
> >> + goto out;
> >> + }
> >>
> >> if (low_trigger < -127 || low_trigger > 128 ||
> >> - high_trigger < -127 || high_trigger > 128)
> >> - return -EINVAL;
> >> + high_trigger < -127 || high_trigger > 128) {
> >> + err = -EINVAL;
> >> + goto out;
> >> + }
> >>
> >> rm = kzalloc(sizeof(*rm), GFP_ATOMIC);
> >> - if (!rm)
> >> - return -ENOMEM;
> >> + if (!rm) {
> >> + err = -ENOMEM;
> >> + goto out;
> >> + }
> >>
> >> rm->index = index;
> >> bacpy(&rm->bdaddr, bdaddr);
> >> @@ -1940,20 +1970,46 @@ static int rssi_monitor_add(u16 index, bdaddr_t *bdaddr, s8 low_trigger,
> >>
> >> list_add(&rm->list, &rssi_monitor_list);
> >>
> >> - return 0;
> >> + rssi_monitor_start(index);
> >> +
> >> +out:
> >> + write_unlock_bh(&rssi_monitor_list_lock);
> >> + return err;
> >> }
> >>
> >> static int rssi_monitor_remove(u16 index, bdaddr_t *bdaddr)
> >> {
> >> struct rssi_monitor *rm;
> >> + struct hci_dev *hdev;
> >> + int err = 0;
> >> +
> >> + write_lock_bh(&rssi_monitor_list_lock);
> >>
> >> rm = rssi_monitor_find(index, bdaddr);
> >> - if (!rm)
> >> - return -EINVAL;
> >> + if (!rm) {
> >> + err = -EINVAL;
> >> + goto out;
> >> + }
> >>
> >> list_del(&rm->list);
> >> + kfree(rm);
> >>
> >> - return 0;
> >> + if (!list_empty(&rssi_monitor_list))
> >> + goto out;
> >
> > This need to be a per hdev list, otherwise we will only disable the timer if
> > there is no monitor for all adapters.
>
> Agreed. Will fix it.
>
> >
> >> +
> >> + hdev = hci_dev_get(index);
> >> + if (!hdev) {
> >> + err = -EINVAL;
> >> + goto out;
> >> + }
> >> +
> >> + del_timer(&hdev->rssi_monitor_timer);
> >> +
> >> + hci_dev_put(hdev);
> >> +
> >> +out:
> >> + write_unlock_bh(&rssi_monitor_list_lock);
> >> + return err;
> >> }
> >>
> >> static int enable_rssi_monitor(struct sock *sk, u16 index,
> >> @@ -1995,7 +2051,11 @@ static int rssi_monitor_send_alert(u16 index, bdaddr_t *bdaddr, s8 rssi)
> >> struct mgmt_ev_rssi_monitor_alert ev;
> >> u8 alert;
> >>
> >> + read_lock(&rssi_monitor_list_lock);
> >> +
> >> rm = rssi_monitor_find(index, bdaddr);
> >> +
> >> + read_unlock(&rssi_monitor_list_lock);
> >> if (!rm)
> >> return -EINVAL;
> >>
> >> @@ -2718,3 +2778,22 @@ void mgmt_read_rssi_complete(u16 index, bdaddr_t *bdaddr, s8 rssi, u8 status)
> >>
> >> rssi_monitor_send_alert(index, bdaddr, rssi);
> >> }
> >> +
> >> +void mgmt_do_read_rssi(struct hci_dev *hdev)
> >> +{
> >> + struct rssi_monitor *rm;
> >> +
> >> + read_lock(&rssi_monitor_list_lock);
> >> +
> >> + list_for_each_entry(rm, &rssi_monitor_list, list) {
> >> +
> >> + if (rm->index != hdev->id)
> >> + continue;
> >> +
> >> + mgmt_read_rssi(hdev, &rm->bdaddr);
> >> + }
> >
> > Per adapter list could make this code better as well.
>
> The idea to keep this list only into Management module was to avoid
> modifications in other part of bluetooth code since this RSSI
> monitoring is expected to be implemented inside the controllers. But I
> agree with you, if we have this list per adapter it could simplify the
> code. What should I do? Move the list to hdev?
Just add it to hdev.
I also would like to move all the rssi timer logic to mgmt, to avoid some
round trips between HCI and MGMT
like hci_do_read_rssi -> mgmt_do_read_rssi -> hci_send_cmd.
Also the setup_timer is in hci_core.c and mod_timer is mgmt.c.
I'm still thinking on a good way to do this.
Gustavo
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