linux-kernel - [PATCH v3 1/9] mm/hugetlb: Let vma_offset

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Message-Id: <20221209170100.973970-2-peterx@redhat.com>
Date:   Fri,  9 Dec 2022 12:00:52 -0500
From:   Peter Xu <peterx@...hat.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Miaohe Lin <linmiaohe@...wei.com>,
        David Hildenbrand <david@...hat.com>,
        Nadav Amit <nadav.amit@...il.com>, peterx@...hat.com,
        Andrea Arcangeli <aarcange@...hat.com>,
        Jann Horn <jannh@...gle.com>,
        John Hubbard <jhubbard@...dia.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        James Houghton <jthoughton@...gle.com>,
        Rik van Riel <riel@...riel.com>,
        Muchun Song <songmuchun@...edance.com>
Subject: [PATCH v3 1/9] mm/hugetlb: Let vma_offset_start() to return start

Even though vma_offset_start() is named like that, it's not returning "the
start address of the range" but rather the offset we should use to offset
the vma->vm_start address.

Make it return the real value of the start vaddr, and it also helps for all
the callers because whenever the retval is used, it'll be ultimately added
into the vma->vm_start anyway, so it's better.

Reviewed-by: Mike Kravetz <mike.kravetz@...cle.com>
Reviewed-by: David Hildenbrand <david@...hat.com>
Reviewed-by: John Hubbard <jhubbard@...dia.com>
Signed-off-by: Peter Xu <peterx@...hat.com>
---
 fs/hugetlbfs/inode.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 790d2727141a..fdb16246f46e 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -412,10 +412,12 @@ static bool hugetlb_vma_maps_page(struct vm_area_struct *vma,
  */
 static unsigned long vma_offset_start(struct vm_area_struct *vma, pgoff_t start)
 {
+	unsigned long offset = 0;
+
 	if (vma->vm_pgoff < start)
-		return (start - vma->vm_pgoff) << PAGE_SHIFT;
-	else
-		return 0;
+		offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
+
+	return vma->vm_start + offset;
 }
 
 static unsigned long vma_offset_end(struct vm_area_struct *vma, pgoff_t end)
@@ -457,7 +459,7 @@ static void hugetlb_unmap_file_folio(struct hstate *h,
 		v_start = vma_offset_start(vma, start);
 		v_end = vma_offset_end(vma, end);
 
-		if (!hugetlb_vma_maps_page(vma, vma->vm_start + v_start, page))
+		if (!hugetlb_vma_maps_page(vma, v_start, page))
 			continue;
 
 		if (!hugetlb_vma_trylock_write(vma)) {
@@ -473,8 +475,8 @@ static void hugetlb_unmap_file_folio(struct hstate *h,
 			break;
 		}
 
-		unmap_hugepage_range(vma, vma->vm_start + v_start, v_end,
-				NULL, ZAP_FLAG_DROP_MARKER);
+		unmap_hugepage_range(vma, v_start, v_end, NULL,
+				     ZAP_FLAG_DROP_MARKER);
 		hugetlb_vma_unlock_write(vma);
 	}
 
@@ -507,10 +509,9 @@ static void hugetlb_unmap_file_folio(struct hstate *h,
 		 */
 		v_start = vma_offset_start(vma, start);
 		v_end = vma_offset_end(vma, end);
-		if (hugetlb_vma_maps_page(vma, vma->vm_start + v_start, page))
-			unmap_hugepage_range(vma, vma->vm_start + v_start,
-						v_end, NULL,
-						ZAP_FLAG_DROP_MARKER);
+		if (hugetlb_vma_maps_page(vma, v_start, page))
+			unmap_hugepage_range(vma, v_start, v_end, NULL,
+					     ZAP_FLAG_DROP_MARKER);
 
 		kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
 		hugetlb_vma_unlock_write(vma);
@@ -540,8 +541,7 @@ hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end,
 		v_start = vma_offset_start(vma, start);
 		v_end = vma_offset_end(vma, end);
 
-		unmap_hugepage_range(vma, vma->vm_start + v_start, v_end,
-				     NULL, zap_flags);
+		unmap_hugepage_range(vma, v_start, v_end, NULL, zap_flags);
 
 		/*
 		 * Note that vma lock only exists for shared/non-private
-- 
2.37.3