From: Jason Gunthorpe <jgg@mellanox.com>
Date: Wed, 4 Mar 2020 16:25:56 -0400
Subject: mm/hmm: add missing pfns set to hmm_vma_walk_pmd()
Git-commit: 7d082987e5e562c07a208503a607a733d50553ba
Patch-mainline: v5.7-rc1
References: jsc#SLE-16387

All success exit paths from the walker functions must set the pfns array.

A migration entry with no required fault is a HMM_PFN_NONE return, just
like the pte case.

Fixes: d08faca018c4 ("mm/hmm: properly handle migration pmd")
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/hmm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -402,7 +402,7 @@ again:
 			pmd_migration_entry_wait(walk->mm, pmdp);
 			return -EBUSY;
 		}
-		return 0;
+		return hmm_pfns_fill(start, end, range, HMM_PFN_NONE);
 	} else if (!pmd_present(pmd))
 		return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);