[bpf_iter] get rid of redundant 3rd argument of prepare_seq_file()

[bpf_iter] get rid of redundant 3rd argument of prepare_seq_file()

[Al Viro]

[don't really care which tree that goes through; right now it's
in viro/vfs.git #work.misc, but if somebody prefers to grab it
through a different tree, just say so]
always equal to __get_seq_info(2nd argument)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 kernel/bpf/bpf_iter.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 380e9a7cac75..303ab1f42d3a 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -38,8 +38,7 @@ static DEFINE_MUTEX(link_mutex);
 /* incremented on every opened seq_file */
 static atomic64_t session_id;
 
-static int prepare_seq_file(struct file *file, struct bpf_iter_link *link,
-			    const struct bpf_iter_seq_info *seq_info);
+static int prepare_seq_file(struct file *file, struct bpf_iter_link *link);
 
 static void bpf_iter_inc_seq_num(struct seq_file *seq)
 {
@@ -257,7 +256,7 @@ static int iter_open(struct inode *inode, struct file *file)
 {
 	struct bpf_iter_link *link = inode->i_private;
 
-	return prepare_seq_file(file, link, __get_seq_info(link));
+	return prepare_seq_file(file, link);
 }
 
 static int iter_release(struct inode *inode, struct file *file)
@@ -586,9 +585,9 @@ static void init_seq_meta(struct bpf_iter_priv_data *priv_data,
 	priv_data->done_stop = false;
 }
 
-static int prepare_seq_file(struct file *file, struct bpf_iter_link *link,
-			    const struct bpf_iter_seq_info *seq_info)
+static int prepare_seq_file(struct file *file, struct bpf_iter_link *link)
 {
+	const struct bpf_iter_seq_info *seq_info = __get_seq_info(link);
 	struct bpf_iter_priv_data *priv_data;
 	struct bpf_iter_target_info *tinfo;
 	struct bpf_prog *prog;
@@ -653,7 +652,7 @@ int bpf_iter_new_fd(struct bpf_link *link)
 	}
 
 	iter_link = container_of(link, struct bpf_iter_link, link);
-	err = prepare_seq_file(file, iter_link, __get_seq_info(iter_link));
+	err = prepare_seq_file(file, iter_link);
 	if (err)
 		goto free_file;
 
-- 
2.39.5

Re: [bpf_iter] get rid of redundant 3rd argument of prepare_seq_file()

[Yonghong Song]

On 6/14/25 5:47 PM, Al Viro wrote:
> [don't really care which tree that goes through; right now it's
> in viro/vfs.git #work.misc, but if somebody prefers to grab it
> through a different tree, just say so]
> always equal to __get_seq_info(2nd argument)
>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

LGTM. Thanks for simplifying the code.

Acked-by: Yonghong Song <yonghong.song@linux.dev>

> ---
>   kernel/bpf/bpf_iter.c | 11 +++++------
>   1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
> index 380e9a7cac75..303ab1f42d3a 100644
> --- a/kernel/bpf/bpf_iter.c
> +++ b/kernel/bpf/bpf_iter.c
> @@ -38,8 +38,7 @@ static DEFINE_MUTEX(link_mutex);
>   /* incremented on every opened seq_file */
>   static atomic64_t session_id;
>   
> -static int prepare_seq_file(struct file *file, struct bpf_iter_link *link,
> -			    const struct bpf_iter_seq_info *seq_info);
> +static int prepare_seq_file(struct file *file, struct bpf_iter_link *link);
>   
>   static void bpf_iter_inc_seq_num(struct seq_file *seq)
>   {
> @@ -257,7 +256,7 @@ static int iter_open(struct inode *inode, struct file *file)
>   {
>   	struct bpf_iter_link *link = inode->i_private;
>   
> -	return prepare_seq_file(file, link, __get_seq_info(link));
> +	return prepare_seq_file(file, link);
>   }
>   
>   static int iter_release(struct inode *inode, struct file *file)
> @@ -586,9 +585,9 @@ static void init_seq_meta(struct bpf_iter_priv_data *priv_data,
>   	priv_data->done_stop = false;
>   }
>   
> -static int prepare_seq_file(struct file *file, struct bpf_iter_link *link,
> -			    const struct bpf_iter_seq_info *seq_info)
> +static int prepare_seq_file(struct file *file, struct bpf_iter_link *link)
>   {
> +	const struct bpf_iter_seq_info *seq_info = __get_seq_info(link);
>   	struct bpf_iter_priv_data *priv_data;
>   	struct bpf_iter_target_info *tinfo;
>   	struct bpf_prog *prog;
> @@ -653,7 +652,7 @@ int bpf_iter_new_fd(struct bpf_link *link)
>   	}
>   
>   	iter_link = container_of(link, struct bpf_iter_link, link);
> -	err = prepare_seq_file(file, iter_link, __get_seq_info(iter_link));
> +	err = prepare_seq_file(file, iter_link);
>   	if (err)
>   		goto free_file;
>   

Re: [bpf_iter] get rid of redundant 3rd argument of prepare_seq_file()

[Alexei Starovoitov]

On Sat, Jun 14, 2025 at 5:47 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> [don't really care which tree that goes through; right now it's
> in viro/vfs.git #work.misc, but if somebody prefers to grab it
> through a different tree, just say so]
> always equal to __get_seq_info(2nd argument)

We'll take it through bpf-next,
but it needs a proper commit log that explains the motivation.
Just to clean up the code a bit ?
or something else?

Re: [bpf_iter] get rid of redundant 3rd argument of prepare_seq_file()

[Al Viro]

On Tue, Jun 17, 2025 at 10:31:37AM -0700, Alexei Starovoitov wrote:
> On Sat, Jun 14, 2025 at 5:47 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
> >
> > [don't really care which tree that goes through; right now it's
> > in viro/vfs.git #work.misc, but if somebody prefers to grab it
> > through a different tree, just say so]
> > always equal to __get_seq_info(2nd argument)
> 
> We'll take it through bpf-next,
> but it needs a proper commit log that explains the motivation.
> Just to clean up the code a bit ?
> or something else?

Umm...  It had been sitting around for a couple of years, but IIRC
that was from doing data flow analysis for bpf_iter_seq_info.
I really don't remember details of that code audit, so just chalk
it up to cleaning the code up a bit.

Re: [bpf_iter] get rid of redundant 3rd argument of prepare_seq_file()

[Alexei Starovoitov]

On Tue, Jun 17, 2025 at 2:53 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> On Tue, Jun 17, 2025 at 10:31:37AM -0700, Alexei Starovoitov wrote:
> > On Sat, Jun 14, 2025 at 5:47 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
> > >
> > > [don't really care which tree that goes through; right now it's
> > > in viro/vfs.git #work.misc, but if somebody prefers to grab it
> > > through a different tree, just say so]
> > > always equal to __get_seq_info(2nd argument)
> >
> > We'll take it through bpf-next,
> > but it needs a proper commit log that explains the motivation.
> > Just to clean up the code a bit ?
> > or something else?
>
> Umm...  It had been sitting around for a couple of years, but IIRC
> that was from doing data flow analysis for bpf_iter_seq_info.
> I really don't remember details of that code audit, so just chalk
> it up to cleaning the code up a bit.

Applied to bpf-next.

Re: [bpf_iter] get rid of redundant 3rd argument of prepare_seq_file()

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Sun, 15 Jun 2025 01:47:19 +0100 you wrote:
> [don't really care which tree that goes through; right now it's
> in viro/vfs.git #work.misc, but if somebody prefers to grab it
> through a different tree, just say so]
> always equal to __get_seq_info(2nd argument)
> 
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> 
> [...]

Here is the summary with links:
  - [bpf_iter] get rid of redundant 3rd argument of prepare_seq_file()
    https://git.kernel.org/bpf/bpf-next/c/f5527f0171f0

You are awesome, thank you!
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