Hello, > > > During the review of the patch that fixes DBI access in PCI EP, Rob > > > suggested [1] using a fixed interface for passing the events from EPC to > > > EPF instead of the in-kernel notifiers. > > > > > > This series introduces a simple callback based mechanism for passing the > > > events from EPC to EPF. This interface is chosen for satisfying the below > > > requirements: > > > > > > 1. The notification has to reach the EPF drivers without any additional > > > latency. > > > 2. The context of the caller (EPC) needs to be preserved while passing the > > > notifications. > > > > > > With the existing notifier mechanism, the 1st case can be satisfied since > > > notifiers aren't adding any huge overhead. But the 2nd case is clearly not > > > satisfied, because the current atomic notifiers forces the EPF > > > notification context to be atomic even though the caller (EPC) may not be > > > in atomic context. In the notification function, the EPF drivers are > > > required to call several EPC APIs that might sleep and this triggers a > > > sleeping in atomic bug during runtime. > > > > > > The above issue could be fixed by using a blocking notifier instead of > > > atomic, but that proposal was not accepted either [2]. > > > > > > So instead of working around the issues within the notifiers, let's get rid > > > of it and use the callback mechanism. > > > > > > NOTE: DRA7xx and TEGRA194 drivers are only compile tested. Testing this series > > > on the real platforms is greatly appreciated. > > > > > > > Lorenzo, all patches in this series got review tags. Can you please merge now? > > > > Krzysztof, any update on this series? Sorry for the late reply. I just realised that my question from a few days ago has yet to make it to the mailing list. Again, I apologise for keeping you waiting. Nevertheless, I was asking whether there would be any "Fixes:" tags to add and if we should let the stable maintainers know since this fixes an issue that might be worth back-porting to older kernels. Let me know. Otherwise, everything looks good! Thank you a lot! Krzysztof
