Bluetooth: Add discovery state tracking

This patch adds proper state tracking to the device discovery process.
This makes it possible to return appropriate errors when trying to stop
a non-active discovery or start discovery when it is already ongoing.
Once name resolving is implemented this also makes it possible to know
what the right action to do is when a remote name lookup is cancelled.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>

3 files changed, 44 insertions, 3 deletions

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 55509b0a810a..b68719230601 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -355,6 +355,30 @@ struct hci_dev *hci_dev_get(int index)
 }
 
 /* ---- Inquiry support ---- */
+
+void hci_discovery_set_state(struct hci_dev *hdev, int state)
+{
+        BT_DBG("%s state %u -> %u", hdev->name, hdev->discovery.state, state);
+
+        if (hdev->discovery.state == state)
+                return;
+
+        switch (state) {
+        case DISCOVERY_STOPPED:
+                mgmt_discovering(hdev, 0);
+                break;
+        case DISCOVERY_STARTING:
+                break;
+        case DISCOVERY_ACTIVE:
+                mgmt_discovering(hdev, 1);
+                break;
+        case DISCOVERY_STOPPING:
+                break;
+        }
+
+        hdev->discovery.state = state;
+}
+
 static void inquiry_cache_flush(struct hci_dev *hdev)
 {
         struct discovery_state *cache = &hdev->discovery;
@@ -367,6 +391,7 @@ static void inquiry_cache_flush(struct hci_dev *hdev)
 
         INIT_LIST_HEAD(&cache->unknown);
         INIT_LIST_HEAD(&cache->resolve);
+        cache->state = DISCOVERY_STOPPED;
 }
 
 struct inquiry_entry *hci_inquiry_cache_lookup(struct hci_dev *hdev, bdaddr_t *bdaddr)
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index d4d20df9fbbf..43d69569a0d5 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -65,7 +65,7 @@ static void hci_cc_inquiry_cancel(struct hci_dev *hdev, struct sk_buff *skb)
         clear_bit(HCI_INQUIRY, &hdev->flags);
 
         hci_dev_lock(hdev);
-        mgmt_discovering(hdev, 0);
+        hci_discovery_set_state(hdev, DISCOVERY_STOPPED);
         hci_dev_unlock(hdev);
 
         hci_req_complete(hdev, HCI_OP_INQUIRY_CANCEL, status);
@@ -1119,7 +1119,7 @@ static inline void hci_cs_inquiry(struct hci_dev *hdev, __u8 status)
         set_bit(HCI_INQUIRY, &hdev->flags);
 
         hci_dev_lock(hdev);
-        mgmt_discovering(hdev, 1);
+        hci_discovery_set_state(hdev, DISCOVERY_ACTIVE);
         hci_dev_unlock(hdev);
 }
 
@@ -1507,7 +1507,7 @@ static inline void hci_inquiry_complete_evt(struct hci_dev *hdev, struct sk_buff
                 return;
 
         hci_dev_lock(hdev);
-        mgmt_discovering(hdev, 0);
+        hci_discovery_set_state(hdev, DISCOVERY_STOPPED);
         hci_dev_unlock(hdev);
 }
 
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 894f11bc571d..590966ddfa63 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -1918,6 +1918,12 @@ static int start_discovery(struct sock *sk, u16 index,
                 goto failed;
         }
 
+        if (hdev->discovery.state != DISCOVERY_STOPPED) {
+                err = cmd_status(sk, index, MGMT_OP_START_DISCOVERY,
+                                                MGMT_STATUS_BUSY);
+                goto failed;
+        }
+
         cmd = mgmt_pending_add(sk, MGMT_OP_START_DISCOVERY, hdev, NULL, 0);
         if (!cmd) {
                 err = -ENOMEM;
@@ -1927,6 +1933,8 @@ static int start_discovery(struct sock *sk, u16 index,
         err = hci_do_inquiry(hdev, INQUIRY_LEN_BREDR);
         if (err < 0)
                 mgmt_pending_remove(cmd);
+        else
+                hci_discovery_set_state(hdev, DISCOVERY_STARTING);
 
 failed:
         hci_dev_unlock(hdev);
@@ -1950,6 +1958,12 @@ static int stop_discovery(struct sock *sk, u16 index)
 
         hci_dev_lock(hdev);
 
+        if (hdev->discovery.state != DISCOVERY_ACTIVE) {
+                err = cmd_status(sk, index, MGMT_OP_STOP_DISCOVERY,
+                                                MGMT_STATUS_REJECTED);
+                goto failed;
+        }
+
         cmd = mgmt_pending_add(sk, MGMT_OP_STOP_DISCOVERY, hdev, NULL, 0);
         if (!cmd) {
                 err = -ENOMEM;
@@ -1959,6 +1973,8 @@ static int stop_discovery(struct sock *sk, u16 index)
         err = hci_cancel_inquiry(hdev);
         if (err < 0)
                 mgmt_pending_remove(cmd);
+        else
+                hci_discovery_set_state(hdev, DISCOVERY_STOPPING);
 
 failed:
         hci_dev_unlock(hdev);