linux-kernel - [PATCH 2/2] hugetlb: update vma flag check for hugetlb vma lock

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Date:   Mon, 12 Dec 2022 15:50:42 -0800
From:   Mike Kravetz <mike.kravetz@...cle.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     Muchun Song <songmuchun@...edance.com>,
        Miaohe Lin <linmiaohe@...wei.com>,
        David Hildenbrand <david@...hat.com>,
        Peter Xu <peterx@...hat.com>,
        Naoya Horiguchi <naoya.horiguchi@...ux.dev>,
        "Aneesh Kumar K . V" <aneesh.kumar@...ux.vnet.ibm.com>,
        James Houghton <jthoughton@...gle.com>,
        Mina Almasry <almasrymina@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mike Kravetz <mike.kravetz@...cle.com>
Subject: [PATCH 2/2] hugetlb: update vma flag check for hugetlb vma lock

The check for whether a hugetlb vma lock exists partially depends on
the vma's flags.  Currently, it checks for either VM_MAYSHARE or
VM_SHARED.  The reason both flags are used is because VM_MAYSHARE was
previously cleared in hugetlb vmas as they are tore down.  This is no
longer the case, and only the VM_MAYSHARE check is required.

Signed-off-by: Mike Kravetz <mike.kravetz@...cle.com>
---
 mm/hugetlb.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 9c251faeb6f5..985881f9e8cc 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -260,8 +260,7 @@ static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
  */
 static bool __vma_shareable_lock(struct vm_area_struct *vma)
 {
-	return vma->vm_flags & (VM_MAYSHARE | VM_SHARED) &&
-		vma->vm_private_data;
+	return vma->vm_flags & VM_MAYSHARE && vma->vm_private_data;
 }
 
 void hugetlb_vma_lock_read(struct vm_area_struct *vma)
-- 
2.38.1