• Nicolai Stange's avatar
    debugfs: add support for self-protecting attribute file fops · c6468808
    Nicolai Stange authored
    In order to protect them against file removal issues, debugfs_create_file()
    creates a lifetime managing proxy around each struct file_operations
    handed in.
    In cases where this struct file_operations is able to manage file lifetime
    by itself already, the proxy created by debugfs is a waste of resources.
    The most common class of struct file_operations given to debugfs are those
    defined by means of the DEFINE_SIMPLE_ATTRIBUTE() macro.
    Introduce a DEFINE_DEBUGFS_ATTRIBUTE() macro to allow any
    struct file_operations of this class to be easily made file lifetime aware
    and thus, to be operated unproxied.
    Specifically, introduce debugfs_attr_read() and debugfs_attr_write()
    which wrap simple_attr_read() and simple_attr_write() under the protection
    of a debugfs_use_file_start()/debugfs_use_file_finish() pair.
    Make DEFINE_DEBUGFS_ATTRIBUTE() set the defined struct file_operations'
    ->read() and ->write() members to these wrappers.
    Export debugfs_create_file_unsafe() in order to allow debugfs users to
    create their files in non-proxying operation mode.
    Signed-off-by: default avatarNicolai Stange <nicstange@gmail.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
inode.c 22.8 KB