[PATCH v4 04/24] tracing: Add init callback to trace remotes

[Vincent Donnefort <vdonnefort@google.com>]

Add a .init call back so the trace remote callers can add entries to the
tracefs directory.

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>

diff --git a/include/linux/trace_remote.h b/include/linux/trace_remote.h
index 1aa99da3c96a..82d26d97a536 100644
--- a/include/linux/trace_remote.h
+++ b/include/linux/trace_remote.h
@@ -3,9 +3,11 @@
 #ifndef _LINUX_TRACE_REMOTE_H
 #define _LINUX_TRACE_REMOTE_H
 
+#include <linux/dcache.h>
 #include <linux/ring_buffer.h>
 
 struct trace_remote_callbacks {
+	int	(*init)(struct dentry *d, void *priv);
 	struct trace_buffer_desc *
 		(*load_trace_buffer)(unsigned long size, void *priv);
 	void	(*unload_trace_buffer)(struct trace_buffer_desc *desc, void *priv);
diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c
index 2221705f65f4..6f4b921f6955 100644
--- a/kernel/trace/trace_remote.c
+++ b/kernel/trace/trace_remote.c
@@ -479,6 +479,7 @@ static int trace_remote_init_tracefs(const char *name, struct trace_remote *remo
 int trace_remote_register(const char *name, struct trace_remote_callbacks *cbs, void *priv)
 {
 	struct trace_remote *remote;
+	int ret;
 
 	remote = kzalloc(sizeof(*remote), GFP_KERNEL);
 	if (!remote)
@@ -495,7 +496,11 @@ int trace_remote_register(const char *name, struct trace_remote_callbacks *cbs,
 		return -ENOMEM;
 	}
 
-	return 0;
+	ret = cbs->init ? cbs->init(remote->dentry, priv) : 0;
+	if (ret)
+		pr_err("Init failed for trace remote '%s' (%d)\n", name, ret);
+
+	return ret;
 }
 
 void trace_remote_free_buffer(struct trace_buffer_desc *desc)
-- 
2.49.0.967.g6a0df3ecc3-goog