[openib-general] usermode hang in mthca_cq_clean

[Sean Hefty]

I'm seeing an issue trying to recover from an error in userspace.  Basically, I 
allocate a PD, a CQ, and a QP, then destroy the QP because of an unrelated 
error.  The destroy call takes several seconds to complete, and appears to be 
hung in mthca_cq_clean: line 551.  Stepping through the while loop there, I'm 
not falling into the if or else if cases.  The call does eventually complete.

I will look into this more this afternoon, but thought I'd mention it in case 
there's an obvious issue that someone can see.

- Sean