[openib-general] What context can CM be called from?

[Hal Rosenstock]

On Tue, 2005-03-29 at 19:05, Sean Hefty wrote: 
> Libor Michalek wrote:
> 
> >>With this patch, changing the kmalloc in cm_alloc_msg() to use 
> >>GFP_ATOMIC rather than GFP_KERNEL should allow the CM to be usable from 
> >>interrupt context.  Of course, I haven't actually tested this...
> >>
> >>I have no objection to this change however.
> > 
> >   I could go either way on this issue myself. If the call can only be
> > made from thread context I will use schedule_work() to execute the 
> > request to send the dreq. However, I would imagine that other CM users
> > would want to send requests in interrupt context...
> 
> My intention was that the CM should be able to match the calling 
> conventions of underlying verbs/mad layer routines, except for the 
> destroy_cm_id call that may block.  It should be easy enough to at 
> least test whether the code works at interrupt with these changes, and 
> if not, then call schedule_work until we can identify why not and see 
> if other changes can be made to support it.

Is this just the kmalloc in cm_alloc_msg or is there more to this ?

One other comment/question about cm_alloc_msg:

It seems possible that this is called prior to cm_id_priv->av.port being
initialized. Should an error be returned for this case ?

A follow on to this:
Doing so appears to cause the connection to go into timewait. Is that
correct for these cases ? Not sure what else can be done (perhaps error
?)

-- Hal