From: Liam R. Howlett <Liam.Howlett@oracle.com>
Date: Thu, 23 Oct 2025 19:22:16 +0000 (-0400)
Subject: mm/userfaultfd: move hugetlb_mfill_prepare() into hugetlb_mfill_atomic_pte()
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=21ed4b344666d102e91ee2fe944bddf5b85e76ef;p=users%2Fjedix%2Flinux-maple.git

mm/userfaultfd: move hugetlb_mfill_prepare() into hugetlb_mfill_atomic_pte()

hugetlb_mfill_atomic_pte() is the only user of hugetlb_mfill_prepare(),
so move the call into the function.  Reducing the external hugetlb
calls.

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

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 14701bcd691e..c7e315133beb 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -142,14 +142,9 @@ unsigned long hugetlb_total_pages(void);
 vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 			unsigned long address, unsigned int flags);
 #ifdef CONFIG_USERFAULTFD
-ssize_t hugetlb_mfill_prepare(struct vm_area_struct *dst_vma, unsigned long dst_addr,
-		unsigned long increment, pte_t **dst_pte, u32 *hash, uffd_flags_t flags);
-int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
-			     struct vm_area_struct *dst_vma,
-			     unsigned long dst_addr,
-			     unsigned long src_addr,
-			     uffd_flags_t flags,
-			     struct folio **foliop, u32 hash);
+int hugetlb_mfill_atomic_pte(struct vm_area_struct *dst_vma,
+		unsigned long dst_addr, unsigned long src_addr,
+		uffd_flags_t flags, struct folio **foliop, unsigned long hash);
 #endif /* CONFIG_USERFAULTFD */
 long hugetlb_reserve_pages(struct inode *inode, long from, long to,
 			   struct vm_area_desc *desc, vm_flags_t vm_flags);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 35dfc04b352a..c7409c7cee28 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6904,6 +6904,7 @@ out_mutex:
 
 #ifdef CONFIG_USERFAULTFD
 
+static inline
 ssize_t hugetlb_mfill_prepare(struct vm_area_struct *dst_vma, unsigned long dst_addr,
 		unsigned long increment, pte_t **dst_pte, u32 *hash, uffd_flags_t flags)
 {
@@ -6986,13 +6987,12 @@ static ssize_t hugetlb_is_dst_valid(struct vm_area_struct *dst_vma,
  * Used by userfaultfd UFFDIO_* ioctls. Based on userfaultfd's mfill_atomic_pte
  * with modifications for hugetlb pages.
  */
-int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
-			     struct vm_area_struct *dst_vma,
+int hugetlb_mfill_atomic_pte(struct vm_area_struct *dst_vma,
 			     unsigned long dst_addr,
 			     unsigned long src_addr,
 			     uffd_flags_t flags,
 			     struct folio **foliop,
-			     u32 hash)
+			     unsigned long increment)
 {
 	struct mm_struct *dst_mm = dst_vma->vm_mm;
 	bool is_continue = uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE);
@@ -7003,10 +7003,17 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
 	unsigned long size = huge_page_size(h);
 	int vm_shared = dst_vma->vm_flags & VM_SHARED;
 	pte_t _dst_pte;
+	pte_t *dst_pte;
 	spinlock_t *ptl;
 	int ret = -ENOMEM;
 	struct folio *folio;
 	bool folio_in_pagecache = false;
+	u32 hash;
+
+	ret = hugetlb_mfill_prepare(dst_vma, dst_addr, increment,
+				    &dst_pte, &hash, flags);
+	if (ret)
+		return ret;
 
 	if (uffd_flags_mode_is(flags, MFILL_ATOMIC_POISON)) {
 		ptl = huge_pte_lock(h, dst_mm, dst_pte);
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 82b1046c9037..8134f206c793 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -544,8 +544,7 @@ uffd_ctx_lock_and_validate_dst(struct userfaultfd_ctx *ctx,
  * called with either vma-lock or mmap_lock held, it will release the lock
  * before returning.
  */
-static __always_inline ssize_t mfill_atomic_hugetlb(
-					      struct userfaultfd_ctx *ctx,
+static __always_inline ssize_t mfill_atomic_hugetlb(struct userfaultfd_ctx *ctx,
 					      struct vm_area_struct *dst_vma,
 					      unsigned long dst_start,
 					      unsigned long src_start,
@@ -554,11 +553,9 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
 {
 	struct mm_struct *dst_mm = dst_vma->vm_mm;
 	ssize_t err;
-	pte_t *dst_pte;
 	unsigned long src_addr, dst_addr;
 	long copied;
 	struct folio *folio;
-	u32 hash;
 	const struct vm_uffd_ops *uffd_ops;
 	unsigned long increment;
 
@@ -603,13 +600,8 @@ retry:
 	while (src_addr < src_start + len) {
 		VM_WARN_ON_ONCE(dst_addr >= dst_start + len);
 
-		err = hugetlb_mfill_prepare(dst_vma, dst_addr, increment,
-					    &dst_pte, &hash, flags);
-		if (err)
-			goto out_unlock;
-
-		err = hugetlb_mfill_atomic_pte(dst_pte, dst_vma, dst_addr,
-					       src_addr, flags, &folio, hash);
+		err = hugetlb_mfill_atomic_pte(dst_vma, dst_addr, src_addr,
+					       flags, &folio, increment);
 
 
 		cond_resched();