linux-kernel - [PATCH 71/94] kernel/events/uprobes: Use maple tree iterators instead of linked list

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Date:   Wed, 28 Apr 2021 15:36:22 +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>
CC:     Song Liu <songliubraving@...com>,
        Davidlohr Bueso <dave@...olabs.net>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Matthew Wilcox <willy@...radead.org>,
        Laurent Dufour <ldufour@...ux.ibm.com>,
        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>,
        Michel Lespinasse <walken.cr@...il.com>,
        Liam Howlett <liam.howlett@...cle.com>
Subject: [PATCH 71/94] kernel/events/uprobes: Use maple tree iterators instead
 of linked list

Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 kernel/events/uprobes.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 907d4ee00cb2..8d3248ffbd68 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -355,13 +355,16 @@ static bool valid_ref_ctr_vma(struct uprobe *uprobe,
 static struct vm_area_struct *
 find_ref_ctr_vma(struct uprobe *uprobe, struct mm_struct *mm)
 {
-	struct vm_area_struct *tmp;
+	struct vm_area_struct *tmp = NULL;
+	MA_STATE(mas, &mm->mm_mt, 0, 0);
 
-	for (tmp = mm->mmap; tmp; tmp = tmp->vm_next)
+	rcu_read_lock();
+	mas_for_each(&mas, tmp, ULONG_MAX)
 		if (valid_ref_ctr_vma(uprobe, tmp))
-			return tmp;
+			break;
+	rcu_read_unlock();
 
-	return NULL;
+	return tmp;
 }
 
 static int
@@ -1237,9 +1240,10 @@ static int unapply_uprobe(struct uprobe *uprobe, struct mm_struct *mm)
 {
 	struct vm_area_struct *vma;
 	int err = 0;
+	MA_STATE(mas, &mm->mm_mt, 0, 0);
 
 	mmap_read_lock(mm);
-	for (vma = mm->mmap; vma; vma = vma->vm_next) {
+	mas_for_each(&mas, vma, ULONG_MAX) {
 		unsigned long vaddr;
 		loff_t offset;
 
@@ -1988,8 +1992,10 @@ bool uprobe_deny_signal(void)
 static void mmf_recalc_uprobes(struct mm_struct *mm)
 {
 	struct vm_area_struct *vma;
+	MA_STATE(mas, &mm->mm_mt, 0, 0);
 
-	for (vma = mm->mmap; vma; vma = vma->vm_next) {
+	rcu_read_lock();
+	mas_for_each(&mas, vma, ULONG_MAX) {
 		if (!valid_vma(vma, false))
 			continue;
 		/*
@@ -1999,10 +2005,15 @@ static void mmf_recalc_uprobes(struct mm_struct *mm)
 		 * Or this uprobe can be filtered out.
 		 */
 		if (vma_has_uprobes(vma, vma->vm_start, vma->vm_end))
-			return;
+			goto completed;
 	}
+	rcu_read_unlock();
 
 	clear_bit(MMF_HAS_UPROBES, &mm->flags);
+	return;
+
+completed:
+	rcu_read_unlock();
 }
 
 static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr)
-- 
2.30.2