Re: [PATCH] fs/proc/base: use maple tree iterators in place of linked list

From: Davidlohr Bueso
Date: Thu Aug 25 2022 - 12:19:52 EST


On Wed, 24 Aug 2022, Liam Howlett wrote:

From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>

Use mas_for_each to iterate the list of VMAs instead of a for loop
across the linked list.

Hmm so why isn't this using the standard VMA_ITERATOR?


Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
fs/proc/base.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 93f7e3d971e4..0b72a6d8aac3 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2350,6 +2350,7 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
GENRADIX(struct map_files_info) fa;
struct map_files_info *p;
int ret;
+ MA_STATE(mas, NULL, 0, 0);

genradix_init(&fa);

@@ -2377,6 +2378,7 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
}

nr_files = 0;
+ mas.tree = &mm->mm_mt;

/*
* We need two passes here:
@@ -2388,7 +2390,8 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
* 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)
--
2.35.1