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

Reviewed-by: Steven Rostedt (Google) <[email protected]>
Signed-off-by: Vincent Donnefort <[email protected]>

diff --git a/include/linux/trace_remote.h b/include/linux/trace_remote.h
index 7fb5271a8c30..c4df3d98e5dc 100644
--- a/include/linux/trace_remote.h
+++ b/include/linux/trace_remote.h
@@ -3,11 +3,14 @@
 #ifndef _LINUX_TRACE_REMOTE_H
 #define _LINUX_TRACE_REMOTE_H
 
+#include <linux/dcache.h>
 #include <linux/ring_buffer.h>
 
 /**
  * struct trace_remote_callbacks - Callbacks used by Tracefs to control the 
remote
  *
+ * @init:              Called once the remote has been registered. Allows the
+ *                     caller to extend the Tracefs remote directory
  * @load_trace_buffer:  Called before Tracefs accesses the trace buffer for 
the first
  *                     time. Must return a &trace_buffer_desc
  *                     (most likely filled with trace_remote_alloc_buffer())
@@ -23,6 +26,7 @@
  *                     new reader-page from the @cpu ring-buffer.
  */
 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);
        int     (*enable_tracing)(bool enable, void *priv);
diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c
index e03fde73aac7..8a7662ff775f 100644
--- a/kernel/trace/trace_remote.c
+++ b/kernel/trace/trace_remote.c
@@ -863,6 +863,7 @@ 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)
@@ -880,7 +881,11 @@ 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;
 }
 EXPORT_SYMBOL_GPL(trace_remote_register);
 
-- 
2.53.0.rc1.225.gd81095ad13-goog


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