mm/mmap.c: make vma_merge() comment more easy to understand
Case 1/6, 2/7 and 3/8 have the same pattern and we handle them in the
same logic.
Rearrange the comment to make it a little easy for audience to
understand.
Link: http://lkml.kernel.org/r/20191030012445.16944-1-richardw.yang@linux.intel.com
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mmap.c b/mm/mmap.c
index b9d0c2f..9c64852 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1091,15 +1091,18 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
* the area passed down from mprotect_fixup, never extending beyond one
* vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
*
- * AAAA AAAA AAAA AAAA
- * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
- * cannot merge might become might become might become
- * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
- * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
- * mremap move: PPPPXXXXXXXX 8
- * AAAA
- * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
- * might become case 1 below case 2 below case 3 below
+ * AAAA AAAA AAAA
+ * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN
+ * cannot merge might become might become
+ * PPNNNNNNNNNN PPPPPPPPPPNN
+ * mmap, brk or case 4 below case 5 below
+ * mremap move:
+ * AAAA AAAA
+ * PPPP NNNN PPPPNNNNXXXX
+ * might become might become
+ * PPPPPPPPPPPP 1 or PPPPPPPPPPPP 6 or
+ * PPPPPPPPNNNN 2 or PPPPPPPPXXXX 7 or
+ * PPPPNNNNNNNN 3 PPPPXXXXXXXX 8
*
* It is important for case 8 that the vma NNNN overlapping the
* region AAAA is never going to extended over XXXX. Instead XXXX must