Re: [PATCH v4 05/11] seq_buf: Add seq_buf_strlen()

On Sun, Oct 04, 2026 at 12:26:39AM -0700, Kees Cook wrote:

On Sat, Oct 03, 2026 at 06:36:49PM +0300, Andy Shevchenko wrote:

quoted

On Fri, Oct 02, 2026 at 08:59:10PM -0700, Kees Cook wrote:

...

quoted

quoted

 static inline const char *seq_buf_str(struct seq_buf *s)
 {
-	if (WARN_ON(s->size == 0))
+	if (s->size == 0)
 		return "";
 
-	if (seq_buf_buffer_left(s))
-		s->buffer[s->len] = 0;
-	else
-		s->buffer[s->size - 1] = 0;
+	__seq_buf_terminate(s);
 
 	return s->buffer;
 }

Looking at this again, can't it be rewritten now using _strlen()?

	if (seq_buf_strlen(s))
		return s->buffer;

	return "";

?

It could, but I'm vaguely nervous about the difference between
	s->buffer[0] == '\0'
and
	.data ""

i.e. we only force the return of seq_buf_str() to be _not_ just
s->buffer when s->buffer is weirdly impossible (due to size == 0).
I'd rather not make all 0-len strings return the .data segment's const
"" string...

Good point. Perhaps then to add a short note to the kernel doc,
so we won't see patches based on the suggestion like I gave?

-- 
With Best Regards,
Andy Shevchenko