[openib-general] Re: [PATCH] sdp: replace ip_dev_find withdev_base scan (was Re: ip_dev_find resolution?)

[Sean Hefty]

>> A higher level ULP could map 127.0.0.1 to a specific IP address before
>> calling the CMA, but I'm not sure that's any better.
>
>Ugh. I really would like to hide all the IPv4/IPv6 etc from ULPs.

Not sure that I understand this comment.  The ULP needs to provide some sort of
address.

>> From the CMA's perspective, 127.0.0.1 could just as easily
>> map to an iWarp device as an Infiniband device.
>
>Which device to select is a difficult problem.
>I think we might be able to just punt on this for now, selecting
>an arbitrary device of an appropriate type that happens to be up.

Long term, we may be able to add some quality of service values that help select
devices that map to the same address.

>By the way, CMA seems to happily take bits out of the hardware address
>and assume that these include the gid, pkey, etc.
>Shouldnt it check the device type before doing this?

The validation comes later in the CMA, and is needed there due to hotplug
support, even if an earlier check is done.  So, ib_addr assumes that the address
maps to an IB device and reads out of the hardware address.  The CMA then does a
lookup against known IB devices based on the returned values.

- Sean