On 06-Dec-18 22:07, Jason Gunthorpe wrote: > On Thu, Dec 06, 2018 at 02:53:36PM -0500, Doug Ledford wrote: > >> Then we end up having to duplicate the three or so bugfix patches where >> we moved roce sgid resolution out of the critical path because it can >> sleep. We end up making the code problems we have worse. Better to >> redesign this to remove that atomic assumption. Hence why I had them >> drop the stuff they had. > > The resolution is a slightly different issue, that was to do with > creating the rdma_ah_attr. Once the attr is created then the create_ah > driver callback is non-sleepable.. > >> If we get to the point of having two link layers that can't comply >> with the atomic requirement, then I think it's time to look at >> changing the requirement. > > Sure, and the people who want it changed are responsible :) Don't just > sweep the issue under the rung by ignoring the API contract 'because > it works for me today' > > Jason > We're not trying to sweep anything under the rug, we just can't comply with the atomic requirement. We have two options: 1. Comply with the atomic requirement, this means we will poll the device for completion instead of waiting for an interrupt. 2. Remove the atomic requirement. (1) is fairly simple to implement on the driver side, for (2) we'll need to have a discussion on how we're going to approach this (assuming it is even doable).
