[PATCH v2] mm/migrate_device: Cleanup up PMD Checks and warnings

[Sunny Patel]

Remove the odd VM_WARN_ON_FOLIO(!folio, folio) usage and replace it
with a simpler VM_WARN_ON_ONCE(!folio) check.

Drop the redundant VM_WARN_ON_ONCE(!pmd_none(*pmdp) &&
!is_huge_zero_pmd(*pmdp)).

Refactor the PMD checks, making the control flow
clearer and avoiding duplicate condition checks.

Signed-off-by: Sunny Patel <nueralspacetech@xxxxxxxxx>
---

Changes in v2:
  - Removed additional check for pmd_present() as is_huge_zero_pmd()
  already checks for pmd_present().

Missed it in first version of this patch.

 mm/migrate_device.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 8079676c8f1f..2c7e89a6d1b1 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -807,8 +807,7 @@ static int migrate_vma_insert_huge_pmd_page(struct migrate_vma *migrate,
 	bool flush = false;
 	unsigned long i;
 
-	VM_WARN_ON_FOLIO(!folio, folio);
-	VM_WARN_ON_ONCE(!pmd_none(*pmdp) && !is_huge_zero_pmd(*pmdp));
+	VM_WARN_ON_ONCE(!folio);
 
 	if (!thp_vma_suitable_order(vma, addr, HPAGE_PMD_ORDER))
 		return -EINVAL;
@@ -865,11 +864,9 @@ static int migrate_vma_insert_huge_pmd_page(struct migrate_vma *migrate,
 	if (userfaultfd_missing(vma))
 		goto unlock_abort;
 
-	if (!pmd_none(*pmdp)) {
-		if (!is_huge_zero_pmd(*pmdp))
-			goto unlock_abort;
+	if (is_huge_zero_pmd(*pmdp))
 		flush = true;
-	} else if (!pmd_none(*pmdp))
+	else if (!pmd_none(*pmdp))
 		goto unlock_abort;
 
 	add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
-- 
2.43.0