Commit 78d9cf60 authored by Gonzalo Matias Juarez Tello's avatar Gonzalo Matias Juarez Tello Committed by Linus Torvalds
Browse files

mm/mmap.c: logic of find_vma_intersection repeated in __do_munmap 

Logic of find_vma_intersection() is repeated in __do_munmap().

Also, prev is assigned a value before checking vma->vm_start >= end which
might end up on a return statement making that assignment useless.

Calling find_vma_intersection() checks that condition and returns NULL if
no vma is found, hence only the !vma check is needed in __do_munmap().

Link: https://lkml.kernel.org/r/20210409162129.18313-1-gmjuareztello@gmail.com


Signed-off-by: default avatarGonzalo Matias Juarez Tello <gmjuareztello@gmail.com>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3b8db39f

mm/mmap.c

+2 −7
Original line number Diff line number Diff line
@@ -2828,16 +2828,11 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len, 
	 */

	arch_unmap(mm, start, end);



	/* Find the first overlapping VMA */

	vma = find_vma(mm, start);

	/* Find the first overlapping VMA where start < vma->vm_end */

	vma = find_vma_intersection(mm, start, end);

	if (!vma)

		return 0;

	prev = vma->vm_prev;

	/* we have  start < vma->vm_end  */



	/* if it doesn't overlap, we have nothing.. */

	if (vma->vm_start >= end)

		return 0;



	/*

	 * If we need to split any vma, do it now to save pain later.