[PATCH hmm 3/8] mm/hmm: do not call hmm_vma_walk_hole() while holding a spinlock

[Christoph Hellwig]

On Wed, Mar 11, 2020 at 03:35:01PM -0300, Jason Gunthorpe wrote:
> From: Jason Gunthorpe <jgg at mellanox.com>
> 
> This eventually calls into handle_mm_fault() which is a sleeping function.
> Release the lock first.
> 
> hmm_vma_walk_hole() does not touch the contents of the PUD, so it does not
> need the lock.

So how did this manage to not be noticed before?

The fix looks fine assuming we want something backportable before
starting the cleanups:

Reviewed-by: Christoph Hellwig <hch at lst.de>