From: Arnd Bergmann <a...@arndb.de>

When CONFIG_PERF_EVENTS, a 'make W=1' build produces a warning about the
unused ftrace_event_id_fops variable:

kernel/trace/trace_events.c:2155:37: error: 'ftrace_event_id_fops' defined but 
not used [-Werror=unused-const-variable=]
 2155 | static const struct file_operations ftrace_event_id_fops = {

Hide this in the same #ifdef as the reference to it.

Fixes: 620a30e97feb ("tracing: Don't pass file_operations array to 
event_create_dir()")
Signed-off-by: Arnd Bergmann <a...@arndb.de>
---
 kernel/trace/trace_events.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 7c364b87352e..52f75c36bbca 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1670,6 +1670,7 @@ static int trace_format_open(struct inode *inode, struct 
file *file)
        return 0;
 }
 
+#ifdef CONFIG_PERF_EVENTS
 static ssize_t
 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 {
@@ -1684,6 +1685,7 @@ event_id_read(struct file *filp, char __user *ubuf, 
size_t cnt, loff_t *ppos)
 
        return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
 }
+#endif
 
 static ssize_t
 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
@@ -2152,10 +2154,12 @@ static const struct file_operations 
ftrace_event_format_fops = {
        .release = seq_release,
 };
 
+#ifdef CONFIG_PERF_EVENTS
 static const struct file_operations ftrace_event_id_fops = {
        .read = event_id_read,
        .llseek = default_llseek,
 };
+#endif
 
 static const struct file_operations ftrace_event_filter_fops = {
        .open = tracing_open_file_tr,
-- 
2.39.2


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