Comment 40 for bug 177518

Interesting. I was unaware of spin_lock_bh(), but having looked at it now I agree. If I had seen it before, I would have used it.

But for what it's worth, I didn't use spin_lock_irqsave() without some care first. This spin lock is only ever taken for very short reasonably deterministic, non-blocking intervals in the DRM code (as part of taking a much heavier-weight lock). So I felt that any latency impact from interrupt blockage in these cases should be negligible and thus I didn't really look for a different (potentially more complex solution).

  -Mike