[openib-general] RDMA Generic Connection Management

[Gleb Natapov]

On Thu, Sep 01, 2005 at 09:10:14AM -0700, Sean Hefty wrote:
> Gleb Natapov wrote:
> >On Wed, Aug 31, 2005 at 11:11:40AM -0700, Sean Hefty wrote:
> >
> >>I don't have a good solution yet for calls like ib_cma_get_device().  Yet 
> >>another possibility is to have it return a device pointer in a callback.  
> >>Then it can synchronize with device removal internally.
> >>
> >
> >What if ib_cma_get_device() will return client data for the device and
> >we let the ULP to figure out whether the data is still valid in the way 
> >most suitable for the ULP?
> 
> While I think that returning the client data would be useful, I don't think 
> that this really helps the ULP any.  It seems likely that a client would 
> free their client data upon removal of the associated device.  So they 
> can't trust this pointer any more than the device pointer.
> 
The point is to let client decide how it synchronise access to the data
with remove callback. For instance it may use semaphore like this:

in connect:                           in remove callback:
down(sem)                             down(sem)
ptr = ib_cma_get_device()             free(ptr)
use ptr                               up(sem)
up(sem)

--
			Gleb.