seq_buf: Create seq_buf_used() to find out how much was written

Add a helper function seq_buf_used() that replaces the SEQ_BUF_USED()
private macro to let callers have a method to know how much of the
seq_buf was written to.

Link: http://lkml.kernel.org/r/[e-mail]
Link: http://lkml.kernel.org/r/[e-mail]

Reviewed-by: Petr Mladek <[e-mail]>
Signed-off-by: Steven Rostedt <[e-mail]>

include/linux/seq_buf.h

···
 	return (s->size - 1) - s->len;
 }
 
+/* How much buffer was written? */
+static inline unsigned int seq_buf_used(struct seq_buf *s)
+{
+	return min(s->len, s->size);
+}
+
 extern __printf(2, 3)
 int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
 extern __printf(2, 0)

kernel/trace/seq_buf.c

···
 #include <linux/seq_file.h>
 #include <linux/seq_buf.h>
 
-/* How much buffer is written? */
-#define SEQ_BUF_USED(s) min((s)->len, (s)->size - 1)
-
 /**
  * seq_buf_print_seq - move the contents of seq_buf into a seq_file
  * @m: the seq_file descriptor that is the destination
···
  */
 int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s)
 {
-	unsigned int len = SEQ_BUF_USED(s);
+	unsigned int len = seq_buf_used(s);
 
 	return seq_write(m, s->buffer, len);
 }