seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str()

Solve two ergonomic issues with struct seq_buf;

1) Too much boilerplate is required to initialize:

	struct seq_buf s;
	char buf[32];

	seq_buf_init(s, buf, sizeof(buf));

Instead, we can build this directly on the stack. Provide
DECLARE_SEQ_BUF() macro to do this:

	DECLARE_SEQ_BUF(s, 32);

2) %NUL termination is fragile and requires 2 steps to get a valid
   C String (and is a layering violation exposing the "internals" of
   seq_buf):

	seq_buf_terminate(s);
	do_something(s->buffer);

Instead, we can just return s->buffer directly after terminating it in
the refactored seq_buf_terminate(), now known as seq_buf_str():

	do_something(seq_buf_str(s));

Link: https://lore.kernel.org/linux-trace-kernel/[email protected]
Link: https://lore.kernel.org/linux-trace-kernel/[email protected]/

Cc: Yosry Ahmed <[email protected]>
Cc: "Matthew Wilcox (Oracle)" <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Justin Stitt <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Yun Zhou <[email protected]>
Cc: Jacob Keller <[email protected]>
Cc: Zhen Lei <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

0 files changed, 0 insertions, 0 deletions