2022-03-22 14:18:43

by Miaohe Lin

Subject: [PATCH] mm/mremap: use helper mlock_future_check

Use helper mlock_future_check to check whether it's safe to resize the
locked_vm to simplify the code. Minor readability improvement.

Signed-off-by: Miaohe Lin <[email protected]>
---
mm/mremap.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index 9d76da79594d..e776d4c2345c 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -763,14 +763,8 @@ static struct vm_area_struct *vma_to_resize(unsigned long addr,
if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP))
return ERR_PTR(-EFAULT);

- if (vma->vm_flags & VM_LOCKED) {
- unsigned long locked, lock_limit;
- locked = mm->locked_vm << PAGE_SHIFT;
- lock_limit = rlimit(RLIMIT_MEMLOCK);
- locked += new_len - old_len;
- if (locked > lock_limit && !capable(CAP_IPC_LOCK))
- return ERR_PTR(-EAGAIN);
- }
+ if (mlock_future_check(mm, vma->vm_flags, new_len - old_len))
+ return ERR_PTR(-EAGAIN);

if (!may_expand_vm(mm, vma->vm_flags,
(new_len - old_len) >> PAGE_SHIFT))
--
2.23.0

2022-03-26 19:45:09

by Wei Yang

Subject: Re: [PATCH] mm/mremap: use helper mlock_future_check

On Tue, Mar 22, 2022 at 07:20:04PM +0800, Miaohe Lin wrote:
>Use helper mlock_future_check to check whether it's safe to resize the
>locked_vm to simplify the code. Minor readability improvement.
>
>Signed-off-by: Miaohe Lin <[email protected]>

Reviewed-by: Wei Yang <[email protected]>

--
Wei Yang
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