tracing/fprobe: Remove nr_maxactive from fprobe

Remove depercated fprobe::nr_maxactive. This involves fprobe events to
rejects the maxactive number.

Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/173519007257.391279.946804046982289337.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Author: mhiramat

include/linux/fprobe.h

@@ -54,7 +54,6 @@ struct fprobe_hlist {
  * @nmissed: The counter for missing events.
  * @flags: The status flag.
  * @entry_data_size: The private data storage size.
- * @nr_maxactive: The max number of active functions. (*deprecated)
  * @entry_handler: The callback function for function entry.
  * @exit_handler: The callback function for function exit.
  * @hlist_array: The fprobe_hlist for fprobe search from IP hash table.
@@ -63,7 +62,6 @@ struct fprobe {
 	unsigned long		nmissed;
 	unsigned int		flags;
 	size_t			entry_data_size;
-	int			nr_maxactive;
 
 	fprobe_entry_cb entry_handler;
 	fprobe_exit_cb  exit_handler;

kernel/trace/trace_fprobe.c

@@ -424,7 +424,6 @@ static struct trace_fprobe *alloc_trace_fprobe(const char *group,
 					       const char *symbol,
 					       struct tracepoint *tpoint,
 					       struct module *mod,
-					       int maxactive,
 					       int nargs, bool is_return)
 {
 	struct trace_fprobe *tf;
@@ -445,7 +444,6 @@ static struct trace_fprobe *alloc_trace_fprobe(const char *group,
 
 	tf->tpoint = tpoint;
 	tf->mod = mod;
-	tf->fp.nr_maxactive = maxactive;
 
 	ret = trace_probe_init(&tf->tp, event, group, false, nargs);
 	if (ret < 0)
@@ -1098,12 +1096,11 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 	 *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 	 */
 	struct trace_fprobe *tf = NULL;
-	int i, len, new_argc = 0, ret = 0;
+	int i, new_argc = 0, ret = 0;
 	bool is_return = false;
 	char *symbol = NULL;
 	const char *event = NULL, *group = FPROBE_EVENT_SYSTEM;
 	const char **new_argv = NULL;
-	int maxactive = 0;
 	char buf[MAX_EVENT_NAME_LEN];
 	char gbuf[MAX_EVENT_NAME_LEN];
 	char sbuf[KSYM_NAME_LEN];
@@ -1126,33 +1123,13 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 
 	trace_probe_log_init("trace_fprobe", argc, argv);
 
-	event = strchr(&argv[0][1], ':');
-	if (event)
-		event++;
-
-	if (isdigit(argv[0][1])) {
-		if (event)
-			len = event - &argv[0][1] - 1;
-		else
-			len = strlen(&argv[0][1]);
-		if (len > MAX_EVENT_NAME_LEN - 1) {
-			trace_probe_log_err(1, BAD_MAXACT);
-			goto parse_error;
-		}
-		memcpy(buf, &argv[0][1], len);
-		buf[len] = '\0';
-		ret = kstrtouint(buf, 0, &maxactive);
-		if (ret || !maxactive) {
+	if (argv[0][1] != '\0') {
+		if (argv[0][1] != ':') {
+			trace_probe_log_set_index(0);
 			trace_probe_log_err(1, BAD_MAXACT);
 			goto parse_error;
 		}
-		/* fprobe rethook instances are iterated over via a list. The
-		 * maximum should stay reasonable.
-		 */
-		if (maxactive > RETHOOK_MAXACTIVE_MAX) {
-			trace_probe_log_err(1, MAXACT_TOO_BIG);
-			goto parse_error;
-		}
+		event = &argv[0][2];
 	}
 
 	trace_probe_log_set_index(1);
@@ -1162,12 +1139,6 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 	if (ret < 0)
 		goto parse_error;
 
-	if (!is_return && maxactive) {
-		trace_probe_log_set_index(0);
-		trace_probe_log_err(1, BAD_MAXACT_TYPE);
-		goto parse_error;
-	}
-
 	trace_probe_log_set_index(0);
 	if (event) {
 		ret = traceprobe_parse_event_name(&event, &group, gbuf,
@@ -1235,7 +1206,7 @@ static int __trace_fprobe_create(int argc, const char *argv[])
 
 	/* setup a probe */
 	tf = alloc_trace_fprobe(group, event, symbol, tpoint, tp_mod,
-				maxactive, argc, is_return);
+				argc, is_return);
 	if (IS_ERR(tf)) {
 		ret = PTR_ERR(tf);
 		/* This must return -ENOMEM, else there is a bug */
@@ -1315,8 +1286,6 @@ static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev)
 		seq_putc(m, 't');
 	else
 		seq_putc(m, 'f');
-	if (trace_fprobe_is_return(tf) && tf->fp.nr_maxactive)
-		seq_printf(m, "%d", tf->fp.nr_maxactive);
 	seq_printf(m, ":%s/%s", trace_probe_group_name(&tf->tp),
 				trace_probe_name(&tf->tp));