From: Liam R. Howlett <Liam.Howlett@oracle.com>
Date: Thu, 23 Oct 2025 19:36:20 +0000 (-0400)
Subject: mm/userfaultfd: Extract hugetlb recovery from mfill_atomic_hugetlb() loop
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=753417d0f1808fe6d709b934d9e39e3d1dede92d;p=users%2Fjedix%2Flinux-maple.git

mm/userfaultfd: Extract hugetlb recovery from mfill_atomic_hugetlb() loop

Abstracting the recovery of mfill_atomic_hugetlb() calls will lead to a
unity of mfill_atomic() and mfill_atomic_hugetlb().  Since there is a
uffd_ops function pointer for recovery already, this should be called
hugetlb_failed_do_unlock() for a later patch.

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 8134f206c793..c64c63a80e0f 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -539,6 +539,18 @@ uffd_ctx_lock_and_validate_dst(struct userfaultfd_ctx *ctx,
 }
 
 #ifdef CONFIG_HUGETLB_PAGE
+static
+ssize_t hugetlb_failed_do_unlock(struct userfaultfd_ctx *ctx,
+		struct vm_area_struct *dst, struct folio *folio,
+		unsigned long src_addr)
+{
+	up_read(&ctx->map_changing_lock);
+	uffd_mfill_unlock(dst);
+	VM_WARN_ON_ONCE(!folio);
+
+	return copy_folio_from_user(folio,(const void __user *)src_addr, true);
+}
+
 /*
  * mfill_atomic processing for HUGETLB vmas.  Note that this routine is
  * called with either vma-lock or mmap_lock held, it will release the lock
@@ -607,12 +619,8 @@ retry:
 		cond_resched();
 
 		if (unlikely(err == -ENOENT)) {
-			up_read(&ctx->map_changing_lock);
-			uffd_mfill_unlock(dst_vma);
-			VM_WARN_ON_ONCE(!folio);
-
-			err = copy_folio_from_user(folio,
-						   (const void __user *)src_addr, true);
+			err = hugetlb_failed_do_unlock(ctx, dst_vma, folio,
+						       src_addr);
 			if (unlikely(err)) {
 				err = -EFAULT;
 				goto out;