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From:   Liam Howlett <liam.howlett@oracle.com>
To:     "maple-tree@lists.infradead.org" <maple-tree@lists.infradead.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH v5 50/70] fork: Use VMA iterator
Thread-Topic: [PATCH v5 50/70] fork: Use VMA iterator
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Date:   Wed, 2 Feb 2022 02:42:19 +0000
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From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>

The VMA iterator is faster than the linked list and removing the linked
list will shrink the vm_area_struct.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 kernel/fork.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index 2a17d348c3a1..c9f3f82e5a3a 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1229,13 +1229,16 @@ int replace_mm_exe_file(struct mm_struct *mm, struc=
t file *new_exe_file)
 	/* Forbid mm->exe_file change if old file still mapped. */
 	old_exe_file =3D get_mm_exe_file(mm);
 	if (old_exe_file) {
+		VMA_ITERATOR(vmi, mm, 0);
 		mmap_read_lock(mm);
-		for (vma =3D mm->mmap; vma && !ret; vma =3D vma->vm_next) {
+		for_each_vma(vmi, vma) {
 			if (!vma->vm_file)
 				continue;
 			if (path_equal(&vma->vm_file->f_path,
-				       &old_exe_file->f_path))
+				       &old_exe_file->f_path)) {
 				ret =3D -EBUSY;
+				break;
+			}
 		}
 		mmap_read_unlock(mm);
 		fput(old_exe_file);
--=20
2.34.1