RE: [Infiniband-access_layer] ib_dereg_mr fails

[Hefty, S. <sea...@in...>]

>I'm trying to release the memory from a CQ callback function. This
command
>runs after running cl_spinlock_acquire.
>However, this code was released as a part of the SF project code (SRP),
so
>I assumed that it should work fine...

That call should not have been made from a CQ callback.  Memory
registration/deregistration needs to be done without holding a spinlock.

Note that this is a general issue with the Mellanox HCA, and the reason
that most of the IBAL destruction APIs work asynchronously is to allow
destroy calls to be made from any callback.  We made a design decision
not to use asynchronous memory deregistration for security purposes, but
migrating the deregistration call to be asynchronous wouldn't be
difficult.