[ofa-general] Re: libmlx4 wc flash

[Roland Dreier]

 > 	libmlx4 has this comments:
 > 
 > 	/* FIXME flush wc buffers */
 > 
 > 	and since it does *not* currently actually flush the buffers, if we
 > 	enable WC for blueflame, WRs gets mixed in the WC buffer, and QP gets
 > 	corrupted/stuck.
 > 
 > It seems we should we have arch.h under mthca and stick
 > some macro like wc_wmb() in there.
 > 
 > Or, would infiniband/arch.h under libibverbs be a better place?

I think we should add it to infiniband/arch.h but then also have an
#ifndef wc_wmb in libmlx4 until libibverbs with the define is ubiquitous.

 > If WC is not enabled, userspace can avoid the flush - so, should we
 > return such a bit as part of kernel abi?

Maybe, although I'm not sure it's worth it.

 - R.