[PATCH v2 60/70] mm/mprotect: Use maple tree navigation instead of vma linked list

From: Liam R. Howlett
Date: Tue Jan 12 2021 - 11:18:04 EST


Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
mm/mprotect.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 56c02beb60414..a6208b872336e 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -518,6 +518,7 @@ 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);

@@ -549,11 +550,12 @@ 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);
+ mas_set(&mas, start);
+ vma = mas_walk(&mas);
error = -ENOMEM;
if (!vma)
goto out;
- prev = vma->vm_prev;
+ prev = mas_prev(&mas, 0);
if (unlikely(grows & PROT_GROWSDOWN)) {
if (vma->vm_start >= end)
goto out;
@@ -626,7 +628,7 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
if (nstart >= end)
goto out;

- vma = prev->vm_next;
+ vma = mas_next(&mas, ULONG_MAX);
if (!vma || vma->vm_start != nstart) {
error = -ENOMEM;
goto out;
--
2.28.0