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.

Link: https://lkml.kernel.org/r/20210521174745.2219620-22-Liam.Howlett@Oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory.c b/mm/memory.c
index b195ece..3dd6b2e 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4994,8 +4994,8 @@ 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,