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    Subject[RFC] USB: create module_usb_serial_driver macro
    Now that Alan Stern has cleaned up the usb serial driver registration,
    we have the ability to create a module_usb_serial_driver macro to make
    things a bit simpler, like the other *_driver macros created.

    But, as we need two functions here, we can't reuse the existing
    module_driver() macro, so we need to roll our own.

    Lars-Peter, or anyone else, am I missing something here and we can use
    module_driver() somehow, or even modify it, to work for subsystems that
    need 2 parameters for their function calls to register/deregister?

    Actually, if we want to be tricky, we can go back to assigning the
    usb_driver in the usb_serial_driver structure, and just use that pointer
    in the first structure in the list as that option, but that's getting
    pretty opaque just to reuse a single macro...

    Thoughts anyone?

    thanks,

    greg k-h


    Here's a patch implementing module_usb_serial_driver() and it converts
    the pl2303 driver to use it, showing a nice cleanup.

    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>



    --- a/drivers/usb/serial/pl2303.c
    +++ b/drivers/usb/serial/pl2303.c
    @@ -855,23 +855,7 @@ static struct usb_serial_driver * const serial_drivers[] = {
    &pl2303_device, NULL
    };

    -static int __init pl2303_init(void)
    -{
    - int retval;
    -
    - retval = usb_serial_register_drivers(&pl2303_driver, serial_drivers);
    - if (retval == 0)
    - printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_DESC "\n");
    - return retval;
    -}
    -
    -static void __exit pl2303_exit(void)
    -{
    - usb_serial_deregister_drivers(&pl2303_driver, serial_drivers);
    -}
    -
    -module_init(pl2303_init);
    -module_exit(pl2303_exit);
    +module_usb_serial_driver(pl2303_driver, serial_drivers);

    MODULE_DESCRIPTION(DRIVER_DESC);
    MODULE_LICENSE("GPL");
    diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
    index 34c06a7..7b1db84 100644
    --- a/include/linux/usb/serial.h
    +++ b/include/linux/usb/serial.h
    @@ -406,5 +406,33 @@ do { \
    } \
    } while (0)

    +/*
    + * module_usb_serial_driver() - Helper macro for registering a USB Serial driver
    + * @__usb_driver: usb_driver struct to register
    + * @__serial_drivers: list of usb_serial drivers to register
    + *
    + * Helper macro for USB serial drivers which do not do anything special
    + * in module init/exit. This eliminates a lot of boilerplate. Each
    + * module may only use this macro once, and calling it replaces
    + * module_init() and module_exit()
    + *
    + * Note, we can't use the generic module_driver() call here, due to the
    + * two parameters in the usb_serial_* functions, so we roll our own here
    + * :(
    + */
    +#define module_usb_serial_driver(__usb_driver, __serial_drivers) \
    +static int __init usb_serial_driver_init(void) \
    +{ \
    + return usb_serial_register_drivers(&(__usb_driver), \
    + (__serial_drivers)); \
    +} \
    +module_init(usb_serial_driver_init); \
    +static void __exit usb_serial_driver_exit(void) \
    +{ \
    + return usb_serial_deregister_drivers(&(__usb_driver), \
    + (__serial_drivers)); \
    +} \
    +module_exit(usb_serial_driver_exit);
    +
    #endif /* __LINUX_USB_SERIAL_H */


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