linux-kernel - [PATCH 05/13] mm: Introduce vma_pgtable_walk

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20231219075538.414708-6-peterx@redhat.com>
Date: Tue, 19 Dec 2023 15:55:30 +0800
From: peterx@...hat.com
To: linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Cc: Matthew Wilcox <willy@...radead.org>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	Lorenzo Stoakes <lstoakes@...il.com>,
	David Hildenbrand <david@...hat.com>,
	Vlastimil Babka <vbabka@...e.cz>,
	Mike Kravetz <mike.kravetz@...cle.com>,
	Mike Rapoport <rppt@...nel.org>,
	Christoph Hellwig <hch@...radead.org>,
	John Hubbard <jhubbard@...dia.com>,
	Andrew Jones <andrew.jones@...ux.dev>,
	linux-arm-kernel@...ts.infradead.org,
	Michael Ellerman <mpe@...erman.id.au>,
	"Kirill A . Shutemov" <kirill@...temov.name>,
	linuxppc-dev@...ts.ozlabs.org,
	Rik van Riel <riel@...riel.com>,
	linux-riscv@...ts.infradead.org,
	Yang Shi <shy828301@...il.com>,
	James Houghton <jthoughton@...gle.com>,
	"Aneesh Kumar K . V" <aneesh.kumar@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jason Gunthorpe <jgg@...dia.com>,
	Andrea Arcangeli <aarcange@...hat.com>,
	peterx@...hat.com,
	Axel Rasmussen <axelrasmussen@...gle.com>
Subject: [PATCH 05/13] mm: Introduce vma_pgtable_walk_{begin|end}()

From: Peter Xu <peterx@...hat.com>

Introduce per-vma begin()/end() helpers for pgtable walks.  This is a
preparation work to merge hugetlb pgtable walkers with generic mm.

The helpers need to be called before and after a pgtable walk, will start
to be needed if the pgtable walker code supports hugetlb pages.  It's a
hook point for any type of VMA, but for now only hugetlb uses it to
stablize the pgtable pages from getting away (due to possible pmd
unsharing).

Reviewed-by: Christoph Hellwig <hch@...radead.org>
Signed-off-by: Peter Xu <peterx@...hat.com>
---
 include/linux/mm.h |  3 +++
 mm/memory.c        | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index b72bf25a45cf..85e43775824b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -4181,4 +4181,7 @@ static inline bool pfn_is_unaccepted_memory(unsigned long pfn)
 	return range_contains_unaccepted_memory(paddr, paddr + PAGE_SIZE);
 }
 
+void vma_pgtable_walk_begin(struct vm_area_struct *vma);
+void vma_pgtable_walk_end(struct vm_area_struct *vma);
+
 #endif /* _LINUX_MM_H */
diff --git a/mm/memory.c b/mm/memory.c
index 1795aba53cf5..9ac6a9db971e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -6270,3 +6270,15 @@ void ptlock_free(struct ptdesc *ptdesc)
 	kmem_cache_free(page_ptl_cachep, ptdesc->ptl);
 }
 #endif
+
+void vma_pgtable_walk_begin(struct vm_area_struct *vma)
+{
+	if (is_vm_hugetlb_page(vma))
+		hugetlb_vma_lock_read(vma);
+}
+
+void vma_pgtable_walk_end(struct vm_area_struct *vma)
+{
+	if (is_vm_hugetlb_page(vma))
+		hugetlb_vma_unlock_read(vma);
+}
-- 
2.41.0