Re: [PATCH] Bluetooth: Process HCI events in a workqueue instead of a tasklet

[David Vrabel <david.vrabel@csr.com>]

Marcel Holtmann wrote:
> Hi David,
> 
>>>> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
>>>> ---
>>>>  include/net/bluetooth/hci_core.h |    2 +
>>>>  net/bluetooth/hci_core.c         |   58 ++++++++++++++++++++++++++++++++-----
>>>>  2 files changed, 52 insertions(+), 8 deletions(-)
>>> so I stuffed this now into bluetooth-testing tree and would like to see
>>> some extra testing exposure. So far this has only been tested by myself.
>>>
>>> If there are no regression then this should make a lot of HCI and L2CAP
>>> handling a lot simple.
>> This may result in packets being processed in a different order to that 
>> which they were received in.
>>
>> e.g., what happens to an ACL packet processed before the connection 
>> complete event for that connection?
> 
> good point. So we would either a) need to disable the RX tasklet when we
> receive an event and schedule it for processing or b) process the ACL
> data also in a workqueue.

I think my preferred solution would be for the rx function called by the 
HCI transport drivers to be called in a thread context.  There should be 
a helper function that is callable in atomic context that queues the 
packets to be processed in a workqueue.

Our UWB drivers already process packets in a thread so would prefer to 
avoid another thread context switch.

Shall I prepare a patch?

David
-- 
David Vrabel, Senior Software Engineer, Drivers
CSR, Churchill House, Cambridge Business Park,  Tel: +44 (0)1223 692562
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