Man page 9 : debugfs_create_size_t

debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value

struct dentry * debugfs_create_size_t(const char *  name , umode_t  mode , struct dentry *  parent , size_t *  value );

name
    a pointer to a string containing the name of the file to create.

mode
    the permission that the file should have

parent
    a pointer to the parent dentry for this file. This should be a directory dentry if set. If this parameter is NULL, then the file will be created in the root of the debugfs filesystem.

value
    a pointer to the variable that the file should read to and write from.