On Fri, Nov 01, 2019 at 10:29:09AM +0800, Chunfeng Yun wrote: > Try to avoid using extern global variable, and provide two > functions for the usage cases That is 3 different things all in one patch, not generally considered a good thing at all. Also, who is going to use these new functions? Why are they needed? > Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx> > --- > NOTE: > Prepared but not send out patches for drivers using usb_debug_root, > because I'm not sure whether this patch is needed, and many drivers > will be modified. > --- > drivers/usb/common/common.c | 16 ++++++++++++++-- > include/linux/usb.h | 5 ++++- > 2 files changed, 18 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/common/common.c b/drivers/usb/common/common.c > index 1433260d99b4..639ee6d243a2 100644 > --- a/drivers/usb/common/common.c > +++ b/drivers/usb/common/common.c > @@ -293,8 +293,20 @@ struct device *usb_of_get_companion_dev(struct device *dev) > EXPORT_SYMBOL_GPL(usb_of_get_companion_dev); > #endif > > -struct dentry *usb_debug_root; > -EXPORT_SYMBOL_GPL(usb_debug_root); > +static struct dentry *usb_debug_root; Doesn't this break things as-is? You can't do that in a single patch either :( > + > +struct dentry *usb_debugfs_create_dir(const char *name) > +{ > + return debugfs_create_dir(name, usb_debug_root); > +} > +EXPORT_SYMBOL_GPL(usb_debugfs_create_dir); > + > +struct dentry *usb_debugfs_create_file(const char *name, umode_t mode, > + void *data, const struct file_operations *fops) > +{ > + return debugfs_create_file(name, mode, usb_debug_root, data, fops); I doubt many people want to create a file in the usb "root" debugfs directory, right? They _should_ be just creating a new subdirectory in there instead. thanks, greg k-h