On Fri, 8 Feb 2008, Roland Dreier wrote: > In general, this MMU notifier stuff will only be useful to a subset of > InfiniBand/RDMA hardware. Some adapters are smart enough to handle > changing the IO virtual -> bus/physical mapping on the fly, but some > aren't. For the dumb adapters, I think the current ib_umem_get() is > pretty close to as good as we can get: we have to keep the physical > pages pinned for as long as the adapter is allowed to DMA into the > memory region.
I thought the adaptor can always remove the mapping by renegotiating with the remote side? Even if its dumb then a callback could notify the driver that it may be required to tear down the mapping. We then hold the pages until we get okay by the driver that the mapping has been removed. We could also let the unmapping fail if the driver indicates that the mapping must stay. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
