linux-kernel - [PATCH v3 30/66] arch/x86: Use maple tree iterators for vdso/vma

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Date:   Tue, 5 Oct 2021 01:30:49 +0000
From:   Liam Howlett <liam.howlett@...cle.com>
To:     "maple-tree@...ts.infradead.org" <maple-tree@...ts.infradead.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        David Hildenbrand <david@...hat.com>,
        Douglas Gilbert <dgilbert@...erlog.com>
CC:     Song Liu <songliubraving@...com>,
        Davidlohr Bueso <dave@...olabs.net>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Matthew Wilcox <willy@...radead.org>,
        David Rientjes <rientjes@...gle.com>,
        Axel Rasmussen <axelrasmussen@...gle.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Rik van Riel <riel@...riel.com>,
        Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH v3 30/66] arch/x86: Use maple tree iterators for vdso/vma

From: "Liam R. Howlett" <Liam.Howlett@...cle.com>

Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 arch/x86/entry/vdso/vma.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 235a5794296a..c0b160a9585d 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -128,15 +128,19 @@ int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
 	struct mm_struct *mm = task->mm;
 	struct vm_area_struct *vma;
 
+	MA_STATE(mas, &mm->mm_mt, 0, 0);
+
 	mmap_read_lock(mm);
+	rcu_read_lock();
 
-	for (vma = mm->mmap; vma; vma = vma->vm_next) {
+	mas_for_each(&mas, vma, ULONG_MAX) {
 		unsigned long size = vma->vm_end - vma->vm_start;
 
 		if (vma_is_special_mapping(vma, &vvar_mapping))
 			zap_page_range(vma, vma->vm_start, size);
 	}
 
+	rcu_read_unlock();
 	mmap_read_unlock(mm);
 	return 0;
 }
@@ -354,6 +358,7 @@ int map_vdso_once(const struct vdso_image *image, unsigned long addr)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
+	MA_STATE(mas, &mm->mm_mt, 0, 0);
 
 	mmap_write_lock(mm);
 	/*
@@ -363,13 +368,16 @@ int map_vdso_once(const struct vdso_image *image, unsigned long addr)
 	 * We could search vma near context.vdso, but it's a slowpath,
 	 * so let's explicitly check all VMAs to be completely sure.
 	 */
-	for (vma = mm->mmap; vma; vma = vma->vm_next) {
+	mas_lock(&mas);
+	mas_for_each(&mas, vma, ULONG_MAX) {
 		if (vma_is_special_mapping(vma, &vdso_mapping) ||
 				vma_is_special_mapping(vma, &vvar_mapping)) {
+			mas_unlock(&mas);
 			mmap_write_unlock(mm);
 			return -EEXIST;
 		}
 	}
+	mas_unlock(&mas);
 	mmap_write_unlock(mm);
 
 	return map_vdso(image, addr);
-- 
2.30.2