[PATCH v4 0/4] Let unmap_hugepage_range() and several related functions to take folio instead of page

[PATCH v4 0/4] Let unmap_hugepage_range() and several related functions to take folio instead of page

[nifan.cxl]

From: Fan Ni <fan.ni@samsung.com>

Changes compared to v3:

Patch 1: 
1) Pick up tags;
2) Reword the commit message a little bit based on feedback;

Patch 2:
1) Pick up tags;

Patch 3:
1) Pick up tags;
2) Update the comment to reflect the use of folio instead of page 
in __unmap_hugepage_range;

Patch 4:
1) Pick up tags;
2) Move folio_provided definition up in the function as suggested;

v3: https://lore.kernel.org/linux-mm/63aec3cb-60a8-4f30-9b12-3ee19c6c14f3@redhat.com/T/#mbbe1f5bdfcf3a70e6b2b1dfba9af35110a5065ec

--------------------------------------------------------------
Cover letter from v3:

[PATCH v3 0/4] mm/hugetlb: Let unmap_hugepage_range() and

From: Fan Ni <fan.ni@samsung.com>

Changes compared to v2,

Patch 1: 
1) Update the commit log subject; 
2) Use &folio->page instead of folio_page(folio) in unmap_ref_private()
  when calling unmap_hugepage_range();

Patch 2:
1) Update the declaration of unmap_hugepage_range() in hugetlb.h;
2) Use &folio->page instead of folio_page(folio) in unmap_hugepage_range()
  when calling __unmap_hugepage_range();

Patch 3: 
1) Update the declaration of __unmap_hugepage_range() in hugetlb.h;
2) Rename ref_folio to folio;
3) compare folio instead of page in __unmap_hugepage_range() when folio is
  provided when calling __unmap_hugepage_range();

Patch 4:
1) Pass folio size instead of huge_page_size() when calling
  tlb_remove_page_size() by Matthew;
2) Update the processing inside __unmap_hugepage_range() when folio
  is provided as sugguested by David Hildenbrand;
3) Since there is some functional change in this patch, we do not pick up the
  tags;

v2:
https://lore.kernel.org/linux-mm/20250418170834.248318-2-nifan.cxl@gmail.com
--------------------------------------------------------------

Fan Ni (4):
  mm/hugetlb: Pass folio instead of page to unmap_ref_private()
  mm/hugetlb: Refactor unmap_hugepage_range() to take folio instead of
    page
  mm/hugetlb: Refactor __unmap_hugepage_range() to take folio instead of
    page
  mm/hugetlb: Convert use of struct page to folio in
    __unmap_hugepage_range()

 include/linux/hugetlb.h |  8 +++----
 mm/hugetlb.c            | 47 ++++++++++++++++++++++-------------------
 2 files changed, 29 insertions(+), 26 deletions(-)

-- 
2.47.2

[PATCH v4 1/4] mm/hugetlb: Pass folio instead of page to unmap_ref_private()

[nifan.cxl]

From: Fan Ni <fan.ni@samsung.com>

The function unmap_ref_private() has only a single user, which passes in
&folio->page. Let it take the folio directly.

Signed-off-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
---
 mm/hugetlb.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0057d1f1dc9a..0c2b264a7ab8 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6071,7 +6071,7 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
  * same region.
  */
 static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
-			      struct page *page, unsigned long address)
+			      struct folio *folio, unsigned long address)
 {
 	struct hstate *h = hstate_vma(vma);
 	struct vm_area_struct *iter_vma;
@@ -6115,7 +6115,8 @@ static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
 		 */
 		if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
 			unmap_hugepage_range(iter_vma, address,
-					     address + huge_page_size(h), page, 0);
+					     address + huge_page_size(h),
+					     &folio->page, 0);
 	}
 	i_mmap_unlock_write(mapping);
 }
@@ -6238,8 +6239,7 @@ static vm_fault_t hugetlb_wp(struct folio *pagecache_folio,
 			hugetlb_vma_unlock_read(vma);
 			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
 
-			unmap_ref_private(mm, vma, &old_folio->page,
-					vmf->address);
+			unmap_ref_private(mm, vma, old_folio, vmf->address);
 
 			mutex_lock(&hugetlb_fault_mutex_table[hash]);
 			hugetlb_vma_lock_read(vma);
-- 
2.47.2

[PATCH v4 2/4] mm/hugetlb: Refactor unmap_hugepage_range() to take folio instead of page

[nifan.cxl]

From: Fan Ni <fan.ni@samsung.com>

The function unmap_hugepage_range() has two kinds of users:
1) unmap_ref_private(), which passes in the head page of a folio.  Since
   unmap_ref_private() already takes folio and there are no other uses
   of the folio struct in the function, it is natural for
   unmap_hugepage_range() to take folio also.
2) All other uses, which pass in NULL pointer.

In both cases, we can pass in folio. Refactor unmap_hugepage_range() to
take folio.

Signed-off-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand <david@redhat.com>
---
 include/linux/hugetlb.h | 4 ++--
 mm/hugetlb.c            | 7 ++++---
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 23ebf49c5d6a..f6d5f24e793c 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -129,8 +129,8 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma,
 int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *,
 			    struct vm_area_struct *, struct vm_area_struct *);
 void unmap_hugepage_range(struct vm_area_struct *,
-			  unsigned long, unsigned long, struct page *,
-			  zap_flags_t);
+			  unsigned long start, unsigned long end,
+			  struct folio *, zap_flags_t);
 void __unmap_hugepage_range(struct mmu_gather *tlb,
 			  struct vm_area_struct *vma,
 			  unsigned long start, unsigned long end,
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0c2b264a7ab8..c339ffe05556 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6046,7 +6046,7 @@ void __hugetlb_zap_end(struct vm_area_struct *vma,
 }
 
 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
-			  unsigned long end, struct page *ref_page,
+			  unsigned long end, struct folio *folio,
 			  zap_flags_t zap_flags)
 {
 	struct mmu_notifier_range range;
@@ -6058,7 +6058,8 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
 	mmu_notifier_invalidate_range_start(&range);
 	tlb_gather_mmu(&tlb, vma->vm_mm);
 
-	__unmap_hugepage_range(&tlb, vma, start, end, ref_page, zap_flags);
+	__unmap_hugepage_range(&tlb, vma, start, end,
+			       &folio->page, zap_flags);
 
 	mmu_notifier_invalidate_range_end(&range);
 	tlb_finish_mmu(&tlb);
@@ -6116,7 +6117,7 @@ static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
 		if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
 			unmap_hugepage_range(iter_vma, address,
 					     address + huge_page_size(h),
-					     &folio->page, 0);
+					     folio, 0);
 	}
 	i_mmap_unlock_write(mapping);
 }
-- 
2.47.2

Re: [PATCH v4 2/4] mm/hugetlb: Refactor unmap_hugepage_range() to take folio instead of page

[Vishal Moola (Oracle)]

On Mon, May 05, 2025 at 11:22:42AM -0700, nifan.cxl@gmail.com wrote:
> From: Fan Ni <fan.ni@samsung.com>
> 
> The function unmap_hugepage_range() has two kinds of users:
> 1) unmap_ref_private(), which passes in the head page of a folio.  Since
>    unmap_ref_private() already takes folio and there are no other uses
>    of the folio struct in the function, it is natural for
>    unmap_hugepage_range() to take folio also.
> 2) All other uses, which pass in NULL pointer.
> 
> In both cases, we can pass in folio. Refactor unmap_hugepage_range() to
> take folio.

It looks like unmap_ref_private() is the only caller that cares about
passing a particular folio to unmap_hugepage_range(). Is there any
reason we shouldn't drop the folio argument and call
__unmap_hugepage_range() directly? 

> Signed-off-by: Fan Ni <fan.ni@samsung.com>
> Reviewed-by: Muchun Song <muchun.song@linux.dev>
> Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
> Reviewed-by: Oscar Salvador <osalvador@suse.de>
> Acked-by: David Hildenbrand <david@redhat.com>
> ---
>  include/linux/hugetlb.h | 4 ++--
>  mm/hugetlb.c            | 7 ++++---
>  2 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 23ebf49c5d6a..f6d5f24e793c 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -129,8 +129,8 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma,
>  int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *,
>  			    struct vm_area_struct *, struct vm_area_struct *);
>  void unmap_hugepage_range(struct vm_area_struct *,
> -			  unsigned long, unsigned long, struct page *,
> -			  zap_flags_t);
> +			  unsigned long start, unsigned long end,
> +			  struct folio *, zap_flags_t);
>  void __unmap_hugepage_range(struct mmu_gather *tlb,
>  			  struct vm_area_struct *vma,
>  			  unsigned long start, unsigned long end,
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 0c2b264a7ab8..c339ffe05556 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -6046,7 +6046,7 @@ void __hugetlb_zap_end(struct vm_area_struct *vma,
>  }
>  
>  void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
> -			  unsigned long end, struct page *ref_page,
> +			  unsigned long end, struct folio *folio,
>  			  zap_flags_t zap_flags)
>  {
>  	struct mmu_notifier_range range;
> @@ -6058,7 +6058,8 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
>  	mmu_notifier_invalidate_range_start(&range);
>  	tlb_gather_mmu(&tlb, vma->vm_mm);
>  
> -	__unmap_hugepage_range(&tlb, vma, start, end, ref_page, zap_flags);
> +	__unmap_hugepage_range(&tlb, vma, start, end,
> +			       &folio->page, zap_flags);
>  
>  	mmu_notifier_invalidate_range_end(&range);
>  	tlb_finish_mmu(&tlb);
> @@ -6116,7 +6117,7 @@ static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
>  		if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
>  			unmap_hugepage_range(iter_vma, address,
>  					     address + huge_page_size(h),
> -					     &folio->page, 0);
> +					     folio, 0);
>  	}
>  	i_mmap_unlock_write(mapping);
>  }
> -- 
> 2.47.2
> 

Re: [PATCH v4 2/4] mm/hugetlb: Refactor unmap_hugepage_range() to take folio instead of page

[Andrew Morton]

On Mon, 5 May 2025 12:59:20 -0700 "Vishal Moola (Oracle)" <vishal.moola@gmail.com> wrote:

> On Mon, May 05, 2025 at 11:22:42AM -0700, nifan.cxl@gmail.com wrote:
> > From: Fan Ni <fan.ni@samsung.com>
> > 
> > The function unmap_hugepage_range() has two kinds of users:
> > 1) unmap_ref_private(), which passes in the head page of a folio.  Since
> >    unmap_ref_private() already takes folio and there are no other uses
> >    of the folio struct in the function, it is natural for
> >    unmap_hugepage_range() to take folio also.
> > 2) All other uses, which pass in NULL pointer.
> > 
> > In both cases, we can pass in folio. Refactor unmap_hugepage_range() to
> > take folio.
> 
> It looks like unmap_ref_private() is the only caller that cares about
> passing a particular folio to unmap_hugepage_range(). Is there any
> reason we shouldn't drop the folio argument and call
> __unmap_hugepage_range() directly? 

afaict there was no response to this review comment.

I'll proceed with the patchset, but please let's not lose sight of this.

[PATCH v4 3/4] mm/hugetlb: Refactor __unmap_hugepage_range() to take folio instead of page

[nifan.cxl]

From: Fan Ni <fan.ni@samsung.com>

The function __unmap_hugepage_range() has two kinds of users:
1) unmap_hugepage_range(), which passes in the head page of a folio.
   Since unmap_hugepage_range() already takes folio and there are no other
   uses of the folio struct in the function, it is natural for
   __unmap_hugepage_range() to take folio also.
2) All other uses, which pass in NULL pointer.

In both cases, we can pass in folio. Refactor __unmap_hugepage_range() to
take folio.

Signed-off-by: Fan Ni <fan.ni@samsung.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
---
 include/linux/hugetlb.h |  4 ++--
 mm/hugetlb.c            | 18 +++++++++---------
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index f6d5f24e793c..eb21619206af 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -134,7 +134,7 @@ void unmap_hugepage_range(struct vm_area_struct *,
 void __unmap_hugepage_range(struct mmu_gather *tlb,
 			  struct vm_area_struct *vma,
 			  unsigned long start, unsigned long end,
-			  struct page *ref_page, zap_flags_t zap_flags);
+			  struct folio *, zap_flags_t zap_flags);
 void hugetlb_report_meminfo(struct seq_file *);
 int hugetlb_report_node_meminfo(char *buf, int len, int nid);
 void hugetlb_show_meminfo_node(int nid);
@@ -455,7 +455,7 @@ static inline long hugetlb_change_protection(
 
 static inline void __unmap_hugepage_range(struct mmu_gather *tlb,
 			struct vm_area_struct *vma, unsigned long start,
-			unsigned long end, struct page *ref_page,
+			unsigned long end, struct folio *folio,
 			zap_flags_t zap_flags)
 {
 	BUG();
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index c339ffe05556..443b75e116cf 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5840,7 +5840,7 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma,
 
 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 			    unsigned long start, unsigned long end,
-			    struct page *ref_page, zap_flags_t zap_flags)
+			    struct folio *folio, zap_flags_t zap_flags)
 {
 	struct mm_struct *mm = vma->vm_mm;
 	unsigned long address;
@@ -5913,12 +5913,12 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 
 		page = pte_page(pte);
 		/*
-		 * If a reference page is supplied, it is because a specific
-		 * page is being unmapped, not a range. Ensure the page we
-		 * are about to unmap is the actual page of interest.
+		 * If a folio is supplied, it is because a specific
+		 * folio is being unmapped, not a range. Ensure the folio we
+		 * are about to unmap is the actual folio of interest.
 		 */
-		if (ref_page) {
-			if (page != ref_page) {
+		if (folio) {
+			if (page_folio(page) != folio) {
 				spin_unlock(ptl);
 				continue;
 			}
@@ -5982,9 +5982,9 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 
 		tlb_remove_page_size(tlb, page, huge_page_size(h));
 		/*
-		 * Bail out after unmapping reference page if supplied
+		 * If we were instructed to unmap a specific folio, we're done.
 		 */
-		if (ref_page)
+		if (folio)
 			break;
 	}
 	tlb_end_vma(tlb, vma);
@@ -6059,7 +6059,7 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
 	tlb_gather_mmu(&tlb, vma->vm_mm);
 
 	__unmap_hugepage_range(&tlb, vma, start, end,
-			       &folio->page, zap_flags);
+			       folio, zap_flags);
 
 	mmu_notifier_invalidate_range_end(&range);
 	tlb_finish_mmu(&tlb);
-- 
2.47.2

[PATCH v4 4/4] mm/hugetlb: Convert use of struct page to folio in __unmap_hugepage_range()

[nifan.cxl]

From: Fan Ni <fan.ni@samsung.com>

In __unmap_hugepage_range(), the "page" pointer always points to the
first page of a huge page, which guarantees there is a folio associating
with it.  Convert the "page" pointer to use folio.

Signed-off-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand <david@redhat.com>
---
 mm/hugetlb.c | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 443b75e116cf..d53caf96a4b2 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5843,11 +5843,11 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 			    struct folio *folio, zap_flags_t zap_flags)
 {
 	struct mm_struct *mm = vma->vm_mm;
+	const bool folio_provided = !!folio;
 	unsigned long address;
 	pte_t *ptep;
 	pte_t pte;
 	spinlock_t *ptl;
-	struct page *page;
 	struct hstate *h = hstate_vma(vma);
 	unsigned long sz = huge_page_size(h);
 	bool adjust_reservation = false;
@@ -5911,14 +5911,13 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 			continue;
 		}
 
-		page = pte_page(pte);
 		/*
 		 * If a folio is supplied, it is because a specific
 		 * folio is being unmapped, not a range. Ensure the folio we
 		 * are about to unmap is the actual folio of interest.
 		 */
-		if (folio) {
-			if (page_folio(page) != folio) {
+		if (folio_provided) {
+			if (folio != page_folio(pte_page(pte))) {
 				spin_unlock(ptl);
 				continue;
 			}
@@ -5928,12 +5927,14 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 			 * looking like data was lost
 			 */
 			set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
+		} else {
+			folio = page_folio(pte_page(pte));
 		}
 
 		pte = huge_ptep_get_and_clear(mm, address, ptep, sz);
 		tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
 		if (huge_pte_dirty(pte))
-			set_page_dirty(page);
+			folio_mark_dirty(folio);
 		/* Leave a uffd-wp pte marker if needed */
 		if (huge_pte_uffd_wp(pte) &&
 		    !(zap_flags & ZAP_FLAG_DROP_MARKER))
@@ -5941,7 +5942,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 					make_pte_marker(PTE_MARKER_UFFD_WP),
 					sz);
 		hugetlb_count_sub(pages_per_huge_page(h), mm);
-		hugetlb_remove_rmap(page_folio(page));
+		hugetlb_remove_rmap(folio);
 
 		/*
 		 * Restore the reservation for anonymous page, otherwise the
@@ -5950,8 +5951,8 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		 * reservation bit.
 		 */
 		if (!h->surplus_huge_pages && __vma_private_lock(vma) &&
-		    folio_test_anon(page_folio(page))) {
-			folio_set_hugetlb_restore_reserve(page_folio(page));
+		    folio_test_anon(folio)) {
+			folio_set_hugetlb_restore_reserve(folio);
 			/* Reservation to be adjusted after the spin lock */
 			adjust_reservation = true;
 		}
@@ -5975,16 +5976,17 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 				 * count will not be incremented by free_huge_folio.
 				 * Act as if we consumed the reservation.
 				 */
-				folio_clear_hugetlb_restore_reserve(page_folio(page));
+				folio_clear_hugetlb_restore_reserve(folio);
 			else if (rc)
 				vma_add_reservation(h, vma, address);
 		}
 
-		tlb_remove_page_size(tlb, page, huge_page_size(h));
+		tlb_remove_page_size(tlb, folio_page(folio, 0),
+				     folio_size(folio));
 		/*
 		 * If we were instructed to unmap a specific folio, we're done.
 		 */
-		if (folio)
+		if (folio_provided)
 			break;
 	}
 	tlb_end_vma(tlb, vma);
-- 
2.47.2

Re: [PATCH v4 4/4] mm/hugetlb: Convert use of struct page to folio in __unmap_hugepage_range()

[Andrew Morton]

On Mon,  5 May 2025 11:22:44 -0700 nifan.cxl@gmail.com wrote:

> From: Fan Ni <fan.ni@samsung.com>
> 
> In __unmap_hugepage_range(), the "page" pointer always points to the
> first page of a huge page, which guarantees there is a folio associating
> with it.  Convert the "page" pointer to use folio.
> 
> ...
>
>  		 * Restore the reservation for anonymous page, otherwise the
> @@ -5950,8 +5951,8 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
>  		 * reservation bit.
>  		 */
>  		if (!h->surplus_huge_pages && __vma_private_lock(vma) &&
> -		    folio_test_anon(page_folio(page))) {
> -			folio_set_hugetlb_restore_reserve(page_folio(page));
> +		    folio_test_anon(folio)) {
> +			folio_set_hugetlb_restore_reserve(folio);
>  			/* Reservation to be adjusted after the spin lock */
>  			adjust_reservation = true;
>  		}
> @@ -5975,16 +5976,17 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
>  				 * count will not be incremented by free_huge_folio.
>  				 * Act as if we consumed the reservation.
>  				 */

I did not enjoy reading the above comment, so I did this to it.

The comment would be better if it described why we "Act as if we
consumed the reservation.".  "why, not what".


From: Andrew Morton <akpm@linux-foundation.org>
Subject: mm/hugetlb.c: __unmap_hugepage_range(): comment cleanup
Date: Mon May  5 02:54:25 PM PDT 2025

Wrap to 80 cols, fix a typo, use regular layout, parenthesize function
identifiers, fix grammar and add braces.

Cc: David Hildenbrand <david@redhat.com>
Cc: Fan Ni <fan.ni@samsung.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb.c |   17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

--- a/mm/hugetlb.c~mm-hugetlbc-__unmap_hugepage_range-comment-cleanup
+++ a/mm/hugetlb.c
@@ -5969,16 +5969,19 @@ void __unmap_hugepage_range(struct mmu_g
 		if (adjust_reservation) {
 			int rc = vma_needs_reservation(h, vma, address);
 
-			if (rc < 0)
-				/* Pressumably allocate_file_region_entries failed
-				 * to allocate a file_region struct. Clear
-				 * hugetlb_restore_reserve so that global reserve
-				 * count will not be incremented by free_huge_folio.
-				 * Act as if we consumed the reservation.
+			if (rc < 0) {
+				/*
+				 * Presumably allocate_file_region_entries()
+				 * failed to allocate a file_region struct.
+				 * Clear hugetlb_restore_reserve so that the
+				 * global reserve count will not be incremented
+				 * by free_huge_folio().  Act as if we consumed
+				 * the reservation.
 				 */
 				folio_clear_hugetlb_restore_reserve(folio);
-			else if (rc)
+			} else if (rc) {
 				vma_add_reservation(h, vma, address);
+			}
 		}
 
 		tlb_remove_page_size(tlb, folio_page(folio, 0),
_