[PATCH 05/22] mm/hmm: Only set FAULT_FLAG_ALLOW_RETRY for non-blocking

[Christoph Hellwig]

From: "Kuehling, Felix" <Felix.Kuehling@xxxxxxx>

Don't set this flag by default in hmm_vma_do_fault. It is set
conditionally just a few lines below. Setting it unconditionally can lead
to handle_mm_fault doing a non-blocking fault, returning -EBUSY and
unlocking mmap_sem unexpectedly.

Signed-off-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
Reviewed-by: JÃrÃme Glisse <jglisse@xxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
---
 mm/hmm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/hmm.c b/mm/hmm.c
index dce4e70e648a..826816ab2377 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -328,7 +328,7 @@ struct hmm_vma_walk {
 static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr,
 			    bool write_fault, uint64_t *pfn)
 {
-	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_REMOTE;
+	unsigned int flags = FAULT_FLAG_REMOTE;
 	struct hmm_vma_walk *hmm_vma_walk = walk->private;
 	struct hmm_range *range = hmm_vma_walk->range;
 	struct vm_area_struct *vma = walk->vma;
-- 
2.20.1