From: Liam R. Howlett <Liam.Howlett@oracle.com>
Date: Thu, 18 May 2023 14:55:44 +0000 (-0400)
Subject: mm: avoid rewalk in mmap_region
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5c1c03de1b1636f041a275e777171307cac8d958;p=linux.git

mm: avoid rewalk in mmap_region

If the iterator has moved to the previous entry, then step forward one
range, back to the gap.

Link: https://lkml.kernel.org/r/20230518145544.1722059-36-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vernon Yang <vernon2gm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/mmap.c b/mm/mmap.c
index 19d3c843be0c4..44be7fdfaac91 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2606,6 +2606,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 	}
 
 cannot_expand:
+	if (prev)
+		vma_iter_next_range(&vmi);
+
 	/*
 	 * Determine the object being mapped and call the appropriate
 	 * specific mapper. the address has already been validated, but