tracing: Convert to printbuf

This converts the seq_bufs in dynevent_cmd and trace_seq to printbufs.

 - read_pos in seq_buf doesn't exist in printbuf, so is added to
   trace_seq

 - seq_buf_to_user doesn't have a printbuf equivalent, so is inlined
   into trace_seq_to_user

 - seq_buf_putmem_hex currently swabs bytes on little endian, hardcoded
   to 8 byte units. This patch switches it to prt_hex_bytes(), which
   does _not_ swab.

Otherwise this is largely a direct conversion, with a few slight
refactorings and cleanups.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 203204cadf92..9f270fdde99b 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1022,9 +1022,9 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
 		goto out;
 
 	/* Strip ending newline */
-	if (s->buffer[s->seq.len - 1] == '\n') {
-		s->buffer[s->seq.len - 1] = '\0';
-		s->seq.len--;
+	if (s->buffer[s->seq.pos - 1] == '\n') {
+		s->buffer[s->seq.pos - 1] = '\0';
+		s->seq.pos--;
 	}
 
 	trace_seq_puts(s, " */\n");