Merge 6.4-rc5 into driver-core-next

[platform/kernel/linux-starfive.git] / mm / ksm.c

diff --git a/mm/ksm.c b/mm/ksm.c
index 9e48258..0156bde 100644 (file)
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -2520,6 +2520,22 @@ static void __ksm_add_vma(struct vm_area_struct *vma)
                vm_flags_set(vma, VM_MERGEABLE);
 }
 
+static int __ksm_del_vma(struct vm_area_struct *vma)
+{
+       int err;
+
+       if (!(vma->vm_flags & VM_MERGEABLE))
+               return 0;
+
+       if (vma->anon_vma) {
+               err = unmerge_ksm_pages(vma, vma->vm_start, vma->vm_end);
+               if (err)
+                       return err;
+       }
+
+       vm_flags_clear(vma, VM_MERGEABLE);
+       return 0;
+}
 /**
  * ksm_add_vma - Mark vma as mergeable if compatible
  *
@@ -2542,6 +2558,20 @@ static void ksm_add_vmas(struct mm_struct *mm)
                __ksm_add_vma(vma);
 }
 
+static int ksm_del_vmas(struct mm_struct *mm)
+{
+       struct vm_area_struct *vma;
+       int err;
+
+       VMA_ITERATOR(vmi, mm, 0);
+       for_each_vma(vmi, vma) {
+               err = __ksm_del_vma(vma);
+               if (err)
+                       return err;
+       }
+       return 0;
+}
+
 /**
  * ksm_enable_merge_any - Add mm to mm ksm list and enable merging on all
  *                        compatible VMA's
@@ -2569,6 +2599,46 @@ int ksm_enable_merge_any(struct mm_struct *mm)
        return 0;
 }
 
+/**
+ * ksm_disable_merge_any - Disable merging on all compatible VMA's of the mm,
+ *                        previously enabled via ksm_enable_merge_any().
+ *
+ * Disabling merging implies unmerging any merged pages, like setting
+ * MADV_UNMERGEABLE would. If unmerging fails, the whole operation fails and
+ * merging on all compatible VMA's remains enabled.
+ *
+ * @mm: Pointer to mm
+ *
+ * Returns 0 on success, otherwise error code
+ */
+int ksm_disable_merge_any(struct mm_struct *mm)
+{
+       int err;
+
+       if (!test_bit(MMF_VM_MERGE_ANY, &mm->flags))
+               return 0;
+
+       err = ksm_del_vmas(mm);
+       if (err) {
+               ksm_add_vmas(mm);
+               return err;
+       }
+
+       clear_bit(MMF_VM_MERGE_ANY, &mm->flags);
+       return 0;
+}
+
+int ksm_disable(struct mm_struct *mm)
+{
+       mmap_assert_write_locked(mm);
+
+       if (!test_bit(MMF_VM_MERGEABLE, &mm->flags))
+               return 0;
+       if (test_bit(MMF_VM_MERGE_ANY, &mm->flags))
+               return ksm_disable_merge_any(mm);
+       return ksm_del_vmas(mm);
+}
+
 int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
                unsigned long end, int advice, unsigned long *vm_flags)
 {