[PATCH hmm 1/8] mm/hmm: add missing unmaps of the ptep during hmm_vma_handle_pte()

[Christoph Hellwig]

On Wed, Mar 11, 2020 at 03:34:59PM -0300, Jason Gunthorpe wrote:
> From: Jason Gunthorpe <jgg at mellanox.com>
> 
> Many of the direct returns of error skipped doing the pte_unmap(). All non
> zero exit paths must unmap the pte.
> 
> The pte_unmap() is split unnaturally like this because some of the error
> exit paths trigger a sleep and must release the lock before sleeping.
> 
> Fixes: 992de9a8b751 ("mm/hmm: allow to mirror vma of a file on a DAX backed filesystem")
> Fixes: 53f5c3f489ec ("mm/hmm: factor out pte and pmd handling to simplify hmm_vma_walk_pmd()")
> Signed-off-by: Jason Gunthorpe <jgg at mellanox.com>

Looks good:

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

Probably papered over by the fact that hmm doesn't work on architectures
where pte_unmap isn't a noop right now..