From 1b01814604280127858a4af993320a13066f52ac Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Tue, 28 Mar 2023 16:25:05 -0700 Subject: [PATCH] mm-mmap-vma_merge-set-mid-to-null-if-not-applicable-fix adjust/add comments as suggested by Lorenzo Link: https://lkml.kernel.org/r/def43190-53f7-a607-d1b0-b657565f4288@suse.cz Signed-off-by: Vlastimil Babka Reviewed-by: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton --- mm/mmap.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 98533ce26352..2b72ff3f757c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -861,8 +861,9 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, * * The following mprotect cases have to be considered, where AAAA is * the area passed down from mprotect_fixup, never extending beyond one - * vma, PPPPPP is the prev vma specified, NNNN is a vma that overlaps - * the area AAAA and XXXXXX the next vma after AAAA: + * vma, PPPP is the previous vma, NNNN is a vma that starts at the same + * address as AAAA and is of the same or larger span, and XXXX the next + * vma after AAAA: * * AAAA AAAA AAAA * PPPPPPXXXXXX PPPPPPXXXXXX PPPPPPNNNNNN @@ -933,6 +934,7 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, else next = mid; + /* In cases 1 - 4 there's no NNNN vma */ if (mid && end <= mid->vm_start) mid = NULL; -- 2.50.1