From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>
Subject: fs/proc/base: use maple tree iterators in place of linked list

Link: https://lkml.kernel.org/r/20220426150616.3937571-44-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/proc/base.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/fs/proc/base.c~fs-proc-base-use-maple-tree-iterators-in-place-of-linked-list
+++ a/fs/proc/base.c
@@ -2322,6 +2322,7 @@ proc_map_files_readdir(struct file *file
 	GENRADIX(struct map_files_info) fa;
 	struct map_files_info *p;
 	int ret;
+	MA_STATE(mas, NULL, 0, 0);
 
 	genradix_init(&fa);
 
@@ -2349,6 +2350,7 @@ proc_map_files_readdir(struct file *file
 	}
 
 	nr_files = 0;
+	mas.tree = &mm->mm_mt;
 
 	/*
 	 * We need two passes here:
@@ -2360,7 +2362,8 @@ proc_map_files_readdir(struct file *file
 	 * routine might require mmap_lock taken in might_fault().
 	 */
 
-	for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
+	pos = 2;
+	mas_for_each(&mas, vma, ULONG_MAX) {
 		if (!vma->vm_file)
 			continue;
 		if (++pos <= ctx->pos)
_