[PATCH v3 55/66] mm/mprotect: Use maple tree navigation instead of vma linked list

[Liam Howlett]

From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>

Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
 mm/mprotect.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 883e2cc85cad..a4041d2c0dfb 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -528,6 +528,7 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
 	const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
 	const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
 				(prot & PROT_READ);
+	MA_STATE(mas, &current->mm->mm_mt, start, start);
 
 	start = untagged_addr(start);
 
@@ -559,11 +560,15 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
 	if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
 		goto out;
 
-	vma = find_vma(current->mm, start);
+	rcu_read_lock();
+	vma = mas_find(&mas, ULONG_MAX);
 	error = -ENOMEM;
-	if (!vma)
+	if (!vma) {
+		rcu_read_unlock();
 		goto out;
-	prev = vma->vm_prev;
+	}
+	prev = mas_prev(&mas, 0);
+	rcu_read_unlock();
 	if (unlikely(grows & PROT_GROWSDOWN)) {
 		if (vma->vm_start >= end)
 			goto out;
@@ -644,7 +649,7 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
 		if (nstart >= end)
 			goto out;
 
-		vma = prev->vm_next;
+		vma = vma_next(current->mm, prev);
 		if (!vma || vma->vm_start != nstart) {
 			error = -ENOMEM;
 			goto out;
-- 
2.30.2