From: Sunny Patel <nueralspacetech@gmail.com>
Date: Sun, 19 Apr 2026 17:47:43 +0000 (+0530)
Subject: mm/migrate_device: cleanup up PMD Checks and warnings
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=13fe5736560d6635592b77b1b490fd018af33075;p=thirdparty%2Fkernel%2Flinux.git

mm/migrate_device: cleanup up PMD Checks and warnings

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.

Link: https://lore.kernel.org/20260419174747.10701-1-nueralspacetech@gmail.com
Signed-off-by: Sunny Patel <nueralspacetech@gmail.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 19cd14b34114..554754eb26ff 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -801,8 +801,7 @@ 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;
@@ -859,11 +858,9 @@ 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);