[PATCH hmm 00/15] Consolidate the mmu notifier interval_tree and locking

[Christoph Hellwig]

On Wed, Oct 23, 2019 at 05:24:45PM +0000, Jason Gunthorpe wrote:
> mlx5 is similar, but not currently coded quite right, there is one
> lock that protects the command queue for submitting invalidations to
> the HW and it doesn't make a lot of sense to have additional fine
> grained locking beyond that.

IFF all drivers could agree on a lock type (rw_semaphore?) for this
protection you could add a pointer to the range which would clear
things up a lot.  I'm just not sure you could get everyone to
agree.