mm/mremap: use vma_lookup() in vma_to_resize()

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/20210521174745.2219620-21-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/mremap.c b/mm/mremap.c
index 47c255b..a369a61 100644 (file)
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -634,10 +634,11 @@ static struct vm_area_struct *vma_to_resize(unsigned long addr,
        unsigned long *p)
 {
        struct mm_struct *mm = current->mm;
-       struct vm_area_struct *vma = find_vma(mm, addr);
+       struct vm_area_struct *vma;
        unsigned long pgoff;
 
-       if (!vma || vma->vm_start > addr)
+       vma = vma_lookup(mm, addr);
+       if (!vma)
                return ERR_PTR(-EFAULT);
 
        /*