linux-kernel - [PATCH] mm/mremap: use helper mlock_future

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Date:   Tue, 22 Mar 2022 19:20:04 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <akpm@...ux-foundation.org>
CC:     <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        <linmiaohe@...wei.com>
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 <linmiaohe@...wei.com>
---
 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