[openib-general] Re: [PATCH][RFC] kDAPL: use linux native timers instead of own

[Sean Hefty]

James Lentini wrote:
  > - Could we use cm timeouts?
> 
>   The timers are only used to implement 2 DAT API calls: 
>   dat_ep_connect and dat_ep_dup_connect. Both use a timer to 
>   implement the same feature (cancel connection attempts 
>   after some period of time) and both eventually call 
>   ib_send_cm_req().  ib_send_cm_req() allows the consumer to specify 
>   timeouts. What happens when these timeouts expire? Could DAPL use 
>   these instead of kernel timers? 
> 
>   I don't see an ib_cm_event_type that corresponds to a timeout. This 
>   implies that the CM user's ib_cm_handler is not invoked when one of 
>   these timeout values expires. If so kDAPL wouldn't be able to make
>   use of them. Does anyone know how these work?

The CM will invoke the user's ib_cm_handler with an "ERROR" status if a 
timeout occurs.

For example, a user calls ib_send_cm_req().  If a REP is not received within 
the timeout/retry window, the REQ will fail with IB_CM_REQ_ERROR.  You 
shouldn't need any timers to cancel the connection requests.

- Sean