1 files changed, 36 insertions, 0 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 404acdcd0455..165ea46bf149 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -755,6 +755,21 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
         spinlock_t *ptl;
 
         ptl = pmd_lock(mm, pmd);
+        if (!pmd_none(*pmd)) {
+                if (write) {
+                        if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) {
+                                WARN_ON_ONCE(!is_huge_zero_pmd(*pmd));
+                                goto out_unlock;
+                        }
+                        entry = pmd_mkyoung(*pmd);
+                        entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
+                        if (pmdp_set_access_flags(vma, addr, pmd, entry, 1))
+                                update_mmu_cache_pmd(vma, addr, pmd);
+                }
+
+                goto out_unlock;
+        }
+
         entry = pmd_mkhuge(pfn_t_pmd(pfn, prot));
         if (pfn_t_devmap(pfn))
                 entry = pmd_mkdevmap(entry);
@@ -766,11 +781,16 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
         if (pgtable) {
                 pgtable_trans_huge_deposit(mm, pmd, pgtable);
                 mm_inc_nr_ptes(mm);
+                pgtable = NULL;
         }
 
         set_pmd_at(mm, addr, pmd, entry);
         update_mmu_cache_pmd(vma, addr, pmd);
+
+out_unlock:
         spin_unlock(ptl);
+        if (pgtable)
+                pte_free(mm, pgtable);
 }
 
 vm_fault_t vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
@@ -821,6 +841,20 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
         spinlock_t *ptl;
 
         ptl = pud_lock(mm, pud);
+        if (!pud_none(*pud)) {
+                if (write) {
+                        if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) {
+                                WARN_ON_ONCE(!is_huge_zero_pud(*pud));
+                                goto out_unlock;
+                        }
+                        entry = pud_mkyoung(*pud);
+                        entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma);
+                        if (pudp_set_access_flags(vma, addr, pud, entry, 1))
+                                update_mmu_cache_pud(vma, addr, pud);
+                }
+                goto out_unlock;
+        }
+
         entry = pud_mkhuge(pfn_t_pud(pfn, prot));
         if (pfn_t_devmap(pfn))
                 entry = pud_mkdevmap(entry);
@@ -830,6 +864,8 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
         }
         set_pud_at(mm, addr, pud, entry);
         update_mmu_cache_pud(vma, addr, pud);
+
+out_unlock:
         spin_unlock(ptl);
 }