tracing: Iterate trace_[ku]probe objects directly

As suggested by Linus [1] using list_for_each_entry to iterate
directly trace_[ku]probe objects so we can skip another call to
container_of in these loops.

[1] https://lore.kernel.org/r/CAHk-=wjakjw6-rDzDDBsuMoDCqd+9ogifR_EE1F0K-jYek1CdA@mail.gmail.com

Link: https://lkml.kernel.org/r/20211125202852.406405-1-jolsa@kernel.orgSuggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace_kprobe.c

@@ -327,11 +327,9 @@ static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
 
 static void __disable_trace_kprobe(struct trace_probe *tp)
 {
-	struct trace_probe *pos;
 	struct trace_kprobe *tk;
 
-	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
-		tk = container_of(pos, struct trace_kprobe, tp);
+	list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
 		if (!trace_kprobe_is_registered(tk))
 			continue;
 		if (trace_kprobe_is_return(tk))
@@ -348,7 +346,7 @@ static void __disable_trace_kprobe(struct trace_probe *tp)
 static int enable_trace_kprobe(struct trace_event_call *call,
 				struct trace_event_file *file)
 {
-	struct trace_probe *pos, *tp;
+	struct trace_probe *tp;
 	struct trace_kprobe *tk;
 	bool enabled;
 	int ret = 0;
@@ -369,8 +367,7 @@ static int enable_trace_kprobe(struct trace_event_call *call,
 	if (enabled)
 		return 0;
 
-	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
-		tk = container_of(pos, struct trace_kprobe, tp);
+	list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
 		if (trace_kprobe_has_gone(tk))
 			continue;
 		ret = __enable_trace_kprobe(tk);
@@ -559,11 +556,9 @@ static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
 					 struct trace_kprobe *comp)
 {
 	struct trace_probe_event *tpe = orig->tp.event;
-	struct trace_probe *pos;
 	int i;
 
-	list_for_each_entry(pos, &tpe->probes, list) {
-		orig = container_of(pos, struct trace_kprobe, tp);
+	list_for_each_entry(orig, &tpe->probes, tp.list) {
 		if (strcmp(trace_kprobe_symbol(orig),
 			   trace_kprobe_symbol(comp)) ||
 		    trace_kprobe_offset(orig) != trace_kprobe_offset(comp))

kernel/trace/trace_uprobe.c

@@ -409,12 +409,10 @@ static bool trace_uprobe_has_same_uprobe(struct trace_uprobe *orig,
 					 struct trace_uprobe *comp)
 {
 	struct trace_probe_event *tpe = orig->tp.event;
-	struct trace_probe *pos;
 	struct inode *comp_inode = d_real_inode(comp->path.dentry);
 	int i;
 
-	list_for_each_entry(pos, &tpe->probes, list) {
-		orig = container_of(pos, struct trace_uprobe, tp);
+	list_for_each_entry(orig, &tpe->probes, tp.list) {
 		if (comp_inode != d_real_inode(orig->path.dentry) ||
 		    comp->offset != orig->offset)
 			continue;
@@ -1072,14 +1070,12 @@ static int trace_uprobe_enable(struct trace_uprobe *tu, filter_func_t filter)
 
 static void __probe_event_disable(struct trace_probe *tp)
 {
-	struct trace_probe *pos;
 	struct trace_uprobe *tu;
 
 	tu = container_of(tp, struct trace_uprobe, tp);
 	WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter));
 
-	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
-		tu = container_of(pos, struct trace_uprobe, tp);
+	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
 		if (!tu->inode)
 			continue;
 
@@ -1091,7 +1087,7 @@ static void __probe_event_disable(struct trace_probe *tp)
 static int probe_event_enable(struct trace_event_call *call,
 			struct trace_event_file *file, filter_func_t filter)
 {
-	struct trace_probe *pos, *tp;
+	struct trace_probe *tp;
 	struct trace_uprobe *tu;
 	bool enabled;
 	int ret;
@@ -1126,8 +1122,7 @@ static int probe_event_enable(struct trace_event_call *call,
 	if (ret)
 		goto err_flags;
 
-	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
-		tu = container_of(pos, struct trace_uprobe, tp);
+	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
 		ret = trace_uprobe_enable(tu, filter);
 		if (ret) {
 			__probe_event_disable(tp);
@@ -1272,7 +1267,7 @@ static bool trace_uprobe_filter_add(struct trace_uprobe_filter *filter,
 static int uprobe_perf_close(struct trace_event_call *call,
 			     struct perf_event *event)
 {
-	struct trace_probe *pos, *tp;
+	struct trace_probe *tp;
 	struct trace_uprobe *tu;
 	int ret = 0;
 
@@ -1284,8 +1279,7 @@ static int uprobe_perf_close(struct trace_event_call *call,
 	if (trace_uprobe_filter_remove(tu->tp.event->filter, event))
 		return 0;
 
-	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
-		tu = container_of(pos, struct trace_uprobe, tp);
+	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
 		ret = uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
 		if (ret)
 			break;
@@ -1297,7 +1291,7 @@ static int uprobe_perf_close(struct trace_event_call *call,
 static int uprobe_perf_open(struct trace_event_call *call,
 			    struct perf_event *event)
 {
-	struct trace_probe *pos, *tp;
+	struct trace_probe *tp;
 	struct trace_uprobe *tu;
 	int err = 0;
 
@@ -1309,8 +1303,7 @@ static int uprobe_perf_open(struct trace_event_call *call,
 	if (trace_uprobe_filter_add(tu->tp.event->filter, event))
 		return 0;
 
-	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
-		tu = container_of(pos, struct trace_uprobe, tp);
+	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
 		err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
 		if (err) {
 			uprobe_perf_close(call, event);