Re: [PATCH v2] Bluetooth: Use hci_conn data to handle failed LE Connection Complete

Hi Marcel,

On 16.05.2012 23:48, Marcel Holtmann wrote:

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       hci_dev_lock(hdev);

+     if (ev->status) {
+             conn = hci_conn_hash_lookup_state(hdev, LE_LINK, BT_CONNECT);
+             if (!conn)
+                     goto unlock;
+
+             mgmt_connect_failed(hdev,&conn->dst, conn->type,
+                                 conn->dst_type, ev->status);
+             hci_proto_connect_cfm(conn, ev->status);
+             conn->state = BT_CLOSED;
+             hci_conn_del(conn);
+             goto unlock;
+     }
+
       conn = hci_conn_hash_lookup_ba(hdev, LE_LINK,&ev->bdaddr);
       if (!conn) {
               conn = hci_conn_add(hdev, LE_LINK,&ev->bdaddr);

this change is wrong. We are now treating every single adapter as being
broken. That is not acceptable.

Why do you think these adapters are broken? As I explained in cover
letter for v1, spec does not require peer address to be provided in
Connection Complete which is reasonable since we can only have one
pending connection request. Also as Claudio and Andre noticed such
behaviour could be to simplify whitelist implementation - in case of
connection request using whitelist it does not make sense to include
specific peer address in event.

what has whitelist behavior to do with this event in the failure case?

Just a sidenote on why some vendors may want to omit BD_ADDR and it does 
not make adapter broken. Not directly related to this scenario.

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We should only add a tweak if the BD_ADDR parameter is BDADDR_ANY and
not as a general rule. In addition if we do this, we need to print a
warning to dmesg to make this known.

Perhaps we can just add warning in case BD_ADDR is not BDADDR_ANY and
we cannot find hci_conn for it - in such case most probably something
went wrong.

What are the adapters from Broadcom, CSR, TI and ST are returning in a
failure case? Are they all omitting the BD_ADDR value?

No, I noticed this on BCM and based on previous comments it seems that 
this is what BCM and ST(E) are doing while CSR and TI return BD_ADDR. 
Except that previously I was using ST-E chip which did return BD_ADDR so 
this is not even consistent per manufacturer.

As said before, omitted BD_ADDR seems to be fine from spec perspective 
so we should not require it to be present. Since we can have only one LE 
hci_conn in BT_CONNECT state it's reasonable to use it here. This is 
already in patch.

What could be indeed added to this patch is warning message in case 
BD_ADDR is not BDADDR_ANY and it does not match one stored in hci_conn 
(either adapter returns random BD_ADDR which is weird or something went 
wrong).

BR,
Andrzej