2022-04-01 17:57:03

by Jakob Koschel

Subject: [PATCH 1/2] f2fs: use separate list iterator variable to call list_move_tail()

In preparation to limit the scope of a list iterator to the list
traversal loop, use a dedicated pointer to point to the found element
[1].

If no break is hit or the list is empty, 'next' will be NULL and
list_move_tail() should be called explicitly on the head directly.

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/
Signed-off-by: Jakob Koschel <[email protected]>
---
fs/f2fs/segment.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 22dfeb991529..81ef2c3d08e5 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -4175,16 +4175,20 @@ static void release_sit_entry_set(struct sit_entry_set *ses)
static void adjust_sit_entry_set(struct sit_entry_set *ses,
struct list_head *head)
{
- struct sit_entry_set *next = ses;
+ struct sit_entry_set *next = NULL, *iter = ses;

if (list_is_last(&ses->set_list, head))
return;

- list_for_each_entry_continue(next, head, set_list)
- if (ses->entry_cnt <= next->entry_cnt)
+ list_for_each_entry_continue(iter, head, set_list)
+ if (ses->entry_cnt <= iter->entry_cnt) {
+ next = iter;
+ list_move_tail(&ses->set_list, &iter->set_list);
break;
+ }

- list_move_tail(&ses->set_list, &next->set_list);
+ if (!next)
+ list_move_tail(&ses->set_list, head);
}

static void add_sit_entry(unsigned int segno, struct list_head *head)

base-commit: d888c83fcec75194a8a48ccd283953bdba7b2550
--
2.25.1

2022-04-12 21:22:45

by Jakob Koschel

Subject: Re: [PATCH 1/2] f2fs: use separate list iterator variable to call list_move_tail()

> On 12. Apr 2022, at 11:40, Chao Yu <[email protected]> wrote:
>
> On 2022/4/1 6:16, Jakob Koschel wrote:
>> In preparation to limit the scope of a list iterator to the list
>> traversal loop, use a dedicated pointer to point to the found element
>> [1].
>> If no break is hit or the list is empty, 'next' will be NULL and
>> list_move_tail() should be called explicitly on the head directly.
>> Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/
>> Signed-off-by: Jakob Koschel <[email protected]>
>> ---
>> fs/f2fs/segment.c | 12 ++++++++----
>> 1 file changed, 8 insertions(+), 4 deletions(-)
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index 22dfeb991529..81ef2c3d08e5 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -4175,16 +4175,20 @@ static void release_sit_entry_set(struct sit_entry_set *ses)
>> static void adjust_sit_entry_set(struct sit_entry_set *ses,
>> struct list_head *head)
>> {
>> - struct sit_entry_set *next = ses;
>> + struct sit_entry_set *next = NULL, *iter = ses;
>> if (list_is_last(&ses->set_list, head))
>> return;
>> - list_for_each_entry_continue(next, head, set_list)
>> - if (ses->entry_cnt <= next->entry_cnt)
>> + list_for_each_entry_continue(iter, head, set_list)
>> + if (ses->entry_cnt <= iter->entry_cnt) {
>> + next = iter;
>> + list_move_tail(&ses->set_list, &iter->set_list);
>> break;
>
> return;
>
>> + }
>> - list_move_tail(&ses->set_list, &next->set_list);
>> + if (!next)
>> + list_move_tail(&ses->set_list, head);
>
> list_move_tail(&ses->set_list, head);
>
> Then we don't need @next variable, right?

Of course yes, good spot! I'll fix and resend a v2 in the next days.
Thanks for the input.

>
> Thanks,
>
>> }
>> static void add_sit_entry(unsigned int segno, struct list_head *head)
>> base-commit: d888c83fcec75194a8a48ccd283953bdba7b2550

2022-04-12 22:13:18

by Chao Yu

Subject: Re: [PATCH 1/2] f2fs: use separate list iterator variable to call list_move_tail()

On 2022/4/1 6:16, Jakob Koschel wrote:
> In preparation to limit the scope of a list iterator to the list
> traversal loop, use a dedicated pointer to point to the found element
> [1].
>
> If no break is hit or the list is empty, 'next' will be NULL and
> list_move_tail() should be called explicitly on the head directly.
>
> Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/
> Signed-off-by: Jakob Koschel <[email protected]>
> ---
> fs/f2fs/segment.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 22dfeb991529..81ef2c3d08e5 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -4175,16 +4175,20 @@ static void release_sit_entry_set(struct sit_entry_set *ses)
> static void adjust_sit_entry_set(struct sit_entry_set *ses,
> struct list_head *head)
> {
> - struct sit_entry_set *next = ses;
> + struct sit_entry_set *next = NULL, *iter = ses;
>
> if (list_is_last(&ses->set_list, head))
> return;
>
> - list_for_each_entry_continue(next, head, set_list)
> - if (ses->entry_cnt <= next->entry_cnt)
> + list_for_each_entry_continue(iter, head, set_list)
> + if (ses->entry_cnt <= iter->entry_cnt) {
> + next = iter;
> + list_move_tail(&ses->set_list, &iter->set_list);
> break;

return;

> + }
>
> - list_move_tail(&ses->set_list, &next->set_list);
> + if (!next)
> + list_move_tail(&ses->set_list, head);

list_move_tail(&ses->set_list, head);

Then we don't need @next variable, right?

Thanks,

> }
>
> static void add_sit_entry(unsigned int segno, struct list_head *head)
>
> base-commit: d888c83fcec75194a8a48ccd283953bdba7b2550