[PATCH 0/3] tracing/user_events: More efficient data output in user_seq_show()

[PATCH 0/3] tracing/user_events: More efficient data output in user_seq_show()

[Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Thu, 4 Jun 2026 14:00:56 +0200

A few update suggestions were taken into account
from static source code analysis.

Markus Elfring (3):
  Simplify data output
  Use seq_putc()
  Replace a seq_printf() call by seq_puts()

 kernel/trace/trace_events_user.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

-- 
2.54.0

[PATCH 1/3] tracing/user_events: Simplify data output in user_seq_show()

[Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Thu, 4 Jun 2026 13:33:43 +0200

Move the specification for a line break from a seq_puts() call
to a seq_printf() call.

The source code was transformed by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 kernel/trace/trace_events_user.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index c4ba484f7b38..a089ac30e407 100644
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -2800,8 +2800,7 @@ static int user_seq_show(struct seq_file *m, void *p)
 
 	mutex_unlock(&group->reg_mutex);
 
-	seq_puts(m, "\n");
-	seq_printf(m, "Active: %d\n", active);
+	seq_printf(m, "\nActive: %d\n", active);
 	seq_printf(m, "Busy: %d\n", busy);
 
 	return 0;
-- 
2.54.0

[PATCH 2/3] tracing/user_events: Use seq_putc() in user_seq_show()

[Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Thu, 4 Jun 2026 13:40:38 +0200

A line break should be put into a sequence within a loop.
Thus use the corresponding function “seq_putc” for one selected call.

The source code was transformed by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 kernel/trace/trace_events_user.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index a089ac30e407..1a0569110bfd 100644
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -2794,7 +2794,7 @@ static int user_seq_show(struct seq_file *m, void *p)
 			busy++;
 		}
 
-		seq_puts(m, "\n");
+		seq_putc(m, '\n');
 		active++;
 	}
 
-- 
2.54.0

[PATCH 3/3] tracing/user_events: Replace a seq_printf() call by seq_puts() in user_seq_show()

[Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Thu, 4 Jun 2026 13:45:48 +0200

A single string should be put into a sequence within a loop.
Thus use the corresponding function “seq_puts” for one selected call.

The source code was transformed by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 kernel/trace/trace_events_user.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index 1a0569110bfd..57a78de4dc98 100644
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -2781,7 +2781,7 @@ static int user_seq_show(struct seq_file *m, void *p)
 	hash_for_each(group->register_table, i, user, node) {
 		status = user->status;
 
-		seq_printf(m, "%s", EVENT_TP_NAME(user));
+		seq_puts(m, EVENT_TP_NAME(user));
 
 		if (status != 0) {
 			seq_puts(m, " # Used by");
-- 
2.54.0

Re: [PATCH 1/3] tracing/user_events: Simplify data output in user_seq_show()

[Steven Rostedt]

On Thu, 4 Jun 2026 14:07:45 +0200
Markus Elfring <Markus.Elfring@web.de> wrote:

> --- a/kernel/trace/trace_events_user.c
> +++ b/kernel/trace/trace_events_user.c
> @@ -2800,8 +2800,7 @@ static int user_seq_show(struct seq_file *m, void *p)
>  
>  	mutex_unlock(&group->reg_mutex);
>  
> -	seq_puts(m, "\n");
> -	seq_printf(m, "Active: %d\n", active);
> +	seq_printf(m, "\nActive: %d\n", active);
>  	seq_printf(m, "Busy: %d\n", busy);

This isn't a critical section and I find the original way easier to
read. But the other two patches are fine.

-- Steve

Re: [PATCH 1/3] tracing/user_events: Simplify data output in user_seq_show()

[Markus Elfring]

>> @@ -2800,8 +2800,7 @@ static int user_seq_show(struct seq_file *m, void *p)
>>  
>>  	mutex_unlock(&group->reg_mutex);
>>  
>> -	seq_puts(m, "\n");
>> -	seq_printf(m, "Active: %d\n", active);
>> +	seq_printf(m, "\nActive: %d\n", active);
>>  	seq_printf(m, "Busy: %d\n", busy);
> 
> This isn't a critical section and I find the original way easier to read.

Would you prefer to use a seq_putc() call instead at such a source code place?
https://elixir.bootlin.com/linux/v7.1-rc7/source/kernel/trace/trace_events_user.c#L2803


> But the other two patches are fine.
Thanks for another bit of positive feedback.

Regards,
Markus

Re: [PATCH 1/3] tracing/user_events: Simplify data output in user_seq_show()

[Steven Rostedt]

On Tue, 9 Jun 2026 18:44:04 +0200
Markus Elfring <Markus.Elfring@web.de> wrote:

> >> @@ -2800,8 +2800,7 @@ static int user_seq_show(struct seq_file *m, void *p)
> >>  
> >>  	mutex_unlock(&group->reg_mutex);
> >>  
> >> -	seq_puts(m, "\n");
> >> -	seq_printf(m, "Active: %d\n", active);
> >> +	seq_printf(m, "\nActive: %d\n", active);
> >>  	seq_printf(m, "Busy: %d\n", busy);  
> > 
> > This isn't a critical section and I find the original way easier to read.  
> 
> Would you prefer to use a seq_putc() call instead at such a source code place?
> https://elixir.bootlin.com/linux/v7.1-rc7/source/kernel/trace/trace_events_user.c#L2803

Sure, why not.

-- Steve

[PATCH v2 0/2] tracing/user_events: More efficient data output in two functions

[Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Mon, 22 Jun 2026 16:58:32 +0200

Two update suggestions were taken into account from static source code analysis.

Markus Elfring (2):
  Use seq_putc() in two functions
  Replace a seq_printf() call by seq_puts() in user_seq_show()


v2:
Steven Rostedt requested to use seq_putc() calls more often.


 kernel/trace/trace_events_user.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

-- 
2.54.0

[PATCH v2 1/2] tracing/user_events: Use seq_putc() in two functions

[Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Mon, 22 Jun 2026 16:37:18 +0200

Single characters should be put into a sequence. Thus use the corresponding
function “seq_putc” for selected calls.

The source code was transformed by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 kernel/trace/trace_events_user.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index c4ba484f7b38..a79b7c07dabb 100644
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -1813,7 +1813,7 @@ static int user_event_show(struct seq_file *m, struct dyn_event *ev)
 
 	list_for_each_entry_reverse(field, head, link) {
 		if (depth == 0)
-			seq_puts(m, " ");
+			seq_putc(m, ' ');
 		else
 			seq_puts(m, "; ");
 
@@ -1825,7 +1825,7 @@ static int user_event_show(struct seq_file *m, struct dyn_event *ev)
 		depth++;
 	}
 
-	seq_puts(m, "\n");
+	seq_putc(m, '\n');
 
 	return 0;
 }
@@ -2794,13 +2794,13 @@ static int user_seq_show(struct seq_file *m, void *p)
 			busy++;
 		}
 
-		seq_puts(m, "\n");
+		seq_putc(m, '\n');
 		active++;
 	}
 
 	mutex_unlock(&group->reg_mutex);
 
-	seq_puts(m, "\n");
+	seq_putc(m, '\n');
 	seq_printf(m, "Active: %d\n", active);
 	seq_printf(m, "Busy: %d\n", busy);
 
-- 
2.54.0

[PATCH v2 2/2] tracing/user_events: Replace a seq_printf() call by seq_puts() in user_seq_show()

[Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Mon, 22 Jun 2026 16:42:07 +0200

A single string should be put into a sequence within a loop.
Thus use the corresponding function “seq_puts” for one selected call.

The source code was transformed by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 kernel/trace/trace_events_user.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index a79b7c07dabb..ba9cc168280d 100644
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -2781,7 +2781,7 @@ static int user_seq_show(struct seq_file *m, void *p)
 	hash_for_each(group->register_table, i, user, node) {
 		status = user->status;
 
-		seq_printf(m, "%s", EVENT_TP_NAME(user));
+		seq_puts(m, EVENT_TP_NAME(user));
 
 		if (status != 0) {
 			seq_puts(m, " # Used by");
-- 
2.54.0