On martedì 26 aprile 2022 13:47:34 CEST Sebastian Andrzej Siewior wrote: > > Hmm. It is thread-local in the end. There are slots 0 … KM_MAX_IDX for > the mappings. Slot 0 for task A can be different from slot 0 for task B > while both run on CPU0. So the same address, that is returned from > kmap_local(), will point to a different page for both tasks. Both tasks > can't be migrated to another CPU while the mapping is active. > "CPU local" sounds like something that is same to everyone on the same > CPU which is what this_cpu_read() for instance does. > OK, I agree with you :) I just got three notices from Greg K-H stating that he has applied three of my driver / Android patches. The patches are some conversions from kmap() and / or kmap_atomic() to kmap_local_page() (or wrappers around it): https://lore.kernel.org/lkml/20220425175754.8180-4-fmdefrancesco@xxxxxxxxx/ https://lore.kernel.org/lkml/20220425175754.8180-3-fmdefrancesco@xxxxxxxxx/ https://lore.kernel.org/lkml/20220425175754.8180-2-fmdefrancesco@xxxxxxxxx/ I had forgotten that I wrote the following sentence in all three commit messages: "[] With kmap_local_page(), the mapping is per thread, CPU local and not globally visible. []" Therefore, I'll add "thread-local" or "per thread". I probably like your wording more than mine: "thread-local" is more suitable. For consistency (again) I like the other change you proposed, which is to add "deprecated!" also in kunmap_atomic(), exactly as it is already in kmap_atomic() kernel-docs. However, I will wait one more day before sending v3, in case there are other people who want to suggest further changes. If I remember correctly, I'm overlooking nothing else. Do I overlook something? Thanks for your help, Fabio
