From c0f92ba99bdeaf35f9c580291b4e1a657c67fbd4 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 22 Mar 2009 23:10:44 +0100 Subject: [PATCH] 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 Acked-by: Greg Kroah-Hartman Cc: Steven Rostedt LKML-Reference: <1237759847-21025-2-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar --- fs/debugfs/inode.c | 16 ++++++++++++++++ include/linux/debugfs.h | 8 ++++++++ 2 files changed, 24 insertions(+) diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index 81ae9ea3c6e1..0662ba6de85a 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -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 @@ exit: } 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 @@ static int __init debugfs_init(void) 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); diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index af0e01d4c663..eb5c2ba2f81a 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -71,6 +71,9 @@ struct dentry *debugfs_create_bool(const char *name, mode_t mode, 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 @@ -183,6 +186,11 @@ static inline struct dentry *debugfs_create_blob(const char *name, mode_t mode, return ERR_PTR(-ENODEV); } +static inline bool debugfs_initialized(void) +{ + return false; +} + #endif #endif -- 2.39.5