[PATCH 6/6] mm: Handle write faults to RO pages under the VMA lock

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

I think this is a pretty rare occurrence, but for consistency handle
faults with the VMA lock held the same way that we handle other
faults with the VMA lock held.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/memory.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 5f92126dc527..45ffa0a527ca 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3301,10 +3301,9 @@ static vm_fault_t wp_pfn_shared(struct vm_fault *vmf)
 		vm_fault_t ret;
 
 		pte_unmap_unlock(vmf->pte, vmf->ptl);
-		if (vmf->flags & FAULT_FLAG_VMA_LOCK) {
-			vma_end_read(vmf->vma);
-			return VM_FAULT_RETRY;
-		}
+		ret = vmf_maybe_unlock_vma(vmf);
+		if (ret)
+			return ret;
 
 		vmf->flags |= FAULT_FLAG_MKWRITE;
 		ret = vma->vm_ops->pfn_mkwrite(vmf);
@@ -3328,10 +3327,10 @@ static vm_fault_t wp_page_shared(struct vm_fault *vmf, struct folio *folio)
 		vm_fault_t tmp;
 
 		pte_unmap_unlock(vmf->pte, vmf->ptl);
-		if (vmf->flags & FAULT_FLAG_VMA_LOCK) {
+		tmp = vmf_maybe_unlock_vma(vmf);
+		if (tmp) {
 			folio_put(folio);
-			vma_end_read(vmf->vma);
-			return VM_FAULT_RETRY;
+			return tmp;
 		}
 
 		tmp = do_page_mkwrite(vmf, folio);
-- 
2.40.1