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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: Gonzalo Matias Juarez Tello <gmjuareztello@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Gonzalo Matias Juarez Tello 2021-06-28 19:38:39 -07:00 committed by Linus Torvalds
parent 3b8db39fad
commit 78d9cf6041
1 changed files with 2 additions and 7 deletions
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mm/mmap.c
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@ -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.