This is needed because in handle_pte_fault() pte_offset_map() called
and then fe->ptl is fetched and spin_locked.
This was previously embedded in the call to pte_offset_map_lock().
Signed-off-by: Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 08922b34575d..d19800904272 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2095,6 +2095,13 @@ static inline int wp_page_reuse(struct fault_env *fe, pte_t orig_pte,
return VM_FAULT_WRITE;
}
+static bool pte_spinlock(struct fault_env *fe)
+{
+ fe->ptl = pte_lockptr(fe->vma->vm_mm, fe->pmd);
+ spin_lock(fe->ptl);
+ return true;
+}
+
static bool pte_map_lock(struct fault_env *fe)
{
fe->pte = pte_offset_map_lock(fe->vma->vm_mm, fe->pmd, fe->address, &fe->ptl);
@@ -3366,8 +3373,8 @@ static int do_numa_page(struct fault_env *fe, pte_t pte)
* page table entry is not accessible, so there would be no
* concurrent hardware modifications to the PTE.
*/
- fe->ptl = pte_lockptr(vma->vm_mm, fe->pmd);
- spin_lock(fe->ptl);
+ if (!pte_spinlock(fe))
+ return VM_FAULT_RETRY;
if (unlikely(!pte_same(*fe->pte, pte))) {
pte_unmap_unlock(fe->pte, fe->ptl);
goto out;
@@ -3535,8 +3542,8 @@ static int handle_pte_fault(struct fault_env *fe)
if (pte_protnone(entry) && vma_is_accessible(fe->vma))
return do_numa_page(fe, entry);
- fe->ptl = pte_lockptr(fe->vma->vm_mm, fe->pmd);
- spin_lock(fe->ptl);
+ if (!pte_spinlock(fe))
+ return VM_FAULT_RETRY;
if (unlikely(!pte_same(*fe->pte, entry)))
goto unlock;
if (fe->flags & FAULT_FLAG_WRITE) {
--
2.7.4
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