linux-kernel - [PATCH v2 21/22] mm/memory.c: Use vma_lookup() in __access_remote

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Date:   Fri, 21 May 2021 17:48:07 +0000
From:   Liam Howlett <liam.howlett@...cle.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Laurent Dufour <ldufour@...ux.ibm.com>,
        Davidlohr Bueso <dbueso@...e.de>,
        Liam Howlett <liam.howlett@...cle.com>
Subject: [PATCH v2 21/22] mm/memory.c: Use vma_lookup() in
 __access_remote_vm()

Use vma_lookup() to find the VMA at a specific address.  As vma_lookup()
will return NULL if the address is not within any VMA, the start address
no longer needs to be validated.

Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
Reviewed-by: Laurent Dufour <ldufour@...ux.ibm.com>
Acked-by: David Hildenbrand <david@...hat.com>
Acked-by: Davidlohr Bueso <dbueso@...e.de>
---
 mm/memory.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 86ba6c1f6821..e3b56903b111 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4954,8 +4954,8 @@ int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf,
 			 * Check if this is a VM_IO | VM_PFNMAP VMA, which
 			 * we can access using slightly different code.
 			 */
-			vma = find_vma(mm, addr);
-			if (!vma || vma->vm_start > addr)
+			vma = vma_lookup(mm, addr);
+			if (!vma)
 				break;
 			if (vma->vm_ops && vma->vm_ops->access)
 				ret = vma->vm_ops->access(vma, addr, buf,
-- 
2.30.2