debugfs: function to know if debugfs is initialized

Impact: add new debugfs API With ftrace, some tracers are registered in early initcalls and attempt to create files on the debugfs filesystem. Depending on when they are activated, they can try to create their file at any time. Some checks can be done on the tracing area but providing a helper to know if debugfs is registered make it really more easy. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1237759847-21025-2-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>

debugfs: function to know if debugfs is initialized
Impact: add new debugfs API With ftrace, some tracers are registered in early initcalls and attempt to create files on the debugfs filesystem. Depending on when they are activated, they can try to create their file at any time. Some checks can be done on the tracing area but providing a helper to know if debugfs is registered make it really more easy. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1237759847-21025-2-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Frederic Weisbecker · Ingo Molnar
1 parent b8b9426533
Showing 2 changed files with 24 additions and 0 deletions Side-by-side Diff
fs/debugfs/inode.c
include/linux/debugfs.h
@@ -30,6 +30,7 @@
  
 static struct vfsmount *debugfs_mount;
 static int debugfs_mount_count;
+static bool debugfs_registered;
  
 static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev)
 {
@@ -496,6 +497,16 @@
 }
 EXPORT_SYMBOL_GPL(debugfs_rename);
  
+/**
+ * debugfs_initialized - Tells whether debugfs has been registered
+ */
+bool debugfs_initialized(void)
+{
+	return debugfs_registered;
+}
+EXPORT_SYMBOL_GPL(debugfs_initialized);
+
+
 static struct kobject *debug_kobj;
  
 static int __init debugfs_init(void)
  
@@ -509,11 +520,16 @@
 	retval = register_filesystem(&debug_fs_type);
 	if (retval)
 		kobject_put(debug_kobj);
+	else
+		debugfs_registered = true;
+
 	return retval;
 }
  
 static void __exit debugfs_exit(void)
 {
+	debugfs_registered = false;
+
 	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
 	unregister_filesystem(&debug_fs_type);
 	kobject_put(debug_kobj);
@@ -71,6 +71,9 @@
 struct dentry *debugfs_create_blob(const char *name, mode_t mode,
 				  struct dentry *parent,
 				  struct debugfs_blob_wrapper *blob);
+
+bool debugfs_initialized(void);
+
 #else
  
 #include <linux/err.h>
@@ -181,6 +184,11 @@
 				  struct debugfs_blob_wrapper *blob)
 {
 	return ERR_PTR(-ENODEV);
+}
+
+static inline bool debugfs_initialized(void)
+{
+	return false;
 }
  
 #endif
...	...	@@ -30,6 +30,7 @@
30	30
31	31	static struct vfsmount *debugfs_mount;
32	32	static int debugfs_mount_count;
	33	+static bool debugfs_registered;
33	34
34	35	static struct inode debugfs_get_inode(struct super_block sb, int mode, dev_t dev)
35	36	{
...	...	@@ -496,6 +497,16 @@
496	497	}
497	498	EXPORT_SYMBOL_GPL(debugfs_rename);
498	499
	500	+/**
	501	+ * debugfs_initialized - Tells whether debugfs has been registered
	502	+ */
	503	+bool debugfs_initialized(void)
	504	+{
	505	+ return debugfs_registered;
	506	+}
	507	+EXPORT_SYMBOL_GPL(debugfs_initialized);
	508	+
	509	+
499	510	static struct kobject *debug_kobj;
500	511
501	512	static int __init debugfs_init(void)
502	513
...	...	@@ -509,11 +520,16 @@
509	520	retval = register_filesystem(&debug_fs_type);
510	521	if (retval)
511	522	kobject_put(debug_kobj);
	523	+ else
	524	+ debugfs_registered = true;
	525	+
512	526	return retval;
513	527	}
514	528
515	529	static void __exit debugfs_exit(void)
516	530	{
	531	+ debugfs_registered = false;
	532	+
517	533	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
518	534	unregister_filesystem(&debug_fs_type);
519	535	kobject_put(debug_kobj);
...	...	@@ -71,6 +71,9 @@
71	71	struct dentry debugfs_create_blob(const char name, mode_t mode,
72	72	struct dentry *parent,
73	73	struct debugfs_blob_wrapper *blob);
	74	+
	75	+bool debugfs_initialized(void);
	76	+
74	77	#else
75	78
76	79	#include <linux/err.h>
...	...	@@ -181,6 +184,11 @@
181	184	struct debugfs_blob_wrapper *blob)
182	185	{
183	186	return ERR_PTR(-ENODEV);
	187	+}
	188	+
	189	+static inline bool debugfs_initialized(void)
	190	+{
	191	+ return false;
184	192	}
185	193
186	194	#endif