[PATCH 07/11] tracing: trace_events_synth: Convert to printbuf

[Kent Overstreet]

From: Kent Overstreet <kent.overstreet@xxxxxxxxx>

This converts from seq_buf to printbuf.

This code was using seq_buf for building up dynamically allocated
strings; the conversion uses printbuf's heap allocation functionality to
simplify things (no longer need to calculate size of the output string).

Also, alphabetize the #includes.

Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
---
 kernel/trace/trace_events_synth.c | 51 ++++++++++---------------------
 1 file changed, 16 insertions(+), 35 deletions(-)

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 5e8c07aef0..720c75429c 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -5,13 +5,14 @@
  * Copyright (C) 2015, 2020 Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
  */
 
-#include <linux/module.h>
 #include <linux/kallsyms.h>
-#include <linux/security.h>
+#include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/printbuf.h>
+#include <linux/rculist.h>
+#include <linux/security.h>
 #include <linux/slab.h>
 #include <linux/stacktrace.h>
-#include <linux/rculist.h>
 #include <linux/tracefs.h>
 
 /* for gfp flag names */
@@ -611,7 +612,7 @@ static struct synth_field *parse_synth_field(int argc, char **argv,
 	const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
 	struct synth_field *field;
 	int len, ret = -ENOMEM;
-	struct seq_buf s;
+	struct printbuf buf;
 	ssize_t size;
 
 	if (!strcmp(field_type, "unsigned")) {
@@ -654,28 +655,16 @@ static struct synth_field *parse_synth_field(int argc, char **argv,
 		goto free;
 	}
 
-	len = strlen(field_type) + 1;
-
-	if (array)
-		len += strlen(array);
-
-	if (prefix)
-		len += strlen(prefix);
-
-	field->type = kzalloc(len, GFP_KERNEL);
-	if (!field->type)
-		goto free;
-
-	seq_buf_init(&s, field->type, len);
+	buf = PRINTBUF;
 	if (prefix)
-		seq_buf_puts(&s, prefix);
-	seq_buf_puts(&s, field_type);
+		prt_str(&buf, prefix);
+	prt_str(&buf, field_type);
 	if (array)
-		seq_buf_puts(&s, array);
-	if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
+		prt_str(&buf, array);
+	if (buf.allocation_failure)
 		goto free;
 
-	s.buffer[s.len] = '\0';
+	field->type = buf.buf;
 
 	size = synth_field_size(field->type);
 	if (size < 0) {
@@ -687,23 +676,15 @@ static struct synth_field *parse_synth_field(int argc, char **argv,
 		goto free;
 	} else if (size == 0) {
 		if (synth_field_is_string(field->type)) {
-			char *type;
-
-			len = sizeof("__data_loc ") + strlen(field->type) + 1;
-			type = kzalloc(len, GFP_KERNEL);
-			if (!type)
-				goto free;
-
-			seq_buf_init(&s, type, len);
-			seq_buf_puts(&s, "__data_loc ");
-			seq_buf_puts(&s, field->type);
+			buf = PRINTBUF;
+			prt_str(&buf, "__data_loc ");
+			prt_str(&buf, field->type);
 
-			if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
+			if (buf.allocation_failure)
 				goto free;
-			s.buffer[s.len] = '\0';
 
 			kfree(field->type);
-			field->type = type;
+			field->type = buf.buf;
 
 			field->is_dynamic = true;
 			size = sizeof(u64);
-- 
2.36.1