+ mm-mmapc-logic-of-find_vma_intersection-repeated-in-__do_munmap.patch added to -mm tree

+ mm-mmapc-logic-of-find_vma_intersection-repeated-in-__do_munmap.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm/mmap.c: logic of find_vma_intersection repeated in __do_munmap
has been added to the -mm tree.  Its filename is
     mm-mmapc-logic-of-find_vma_intersection-repeated-in-__do_munmap.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-mmapc-logic-of-find_vma_intersection-repeated-in-__do_munmap.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-mmapc-logic-of-find_vma_intersection-repeated-in-__do_munmap.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Gonzalo Matias Juarez Tello <gmjuareztello@gmail.com>
Subject: 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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mmap.c |    9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

--- a/mm/mmap.c~mm-mmapc-logic-of-find_vma_intersection-repeated-in-__do_munmap
+++ a/mm/mmap.c
@@ -2828,16 +2828,11 @@ int __do_munmap(struct mm_struct *mm, un
 	 */
 	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.
_

Patches currently in -mm which might be from gmjuareztello@gmail.com are

mm-mmapc-logic-of-find_vma_intersection-repeated-in-__do_munmap.patch