devfs_unregister_blkdev - Optionally unregister a conventional block driver.
int devfs_unregister_blkdev (unsigned int major, const char *name);
major The major number for the driver. name The name of the driver (as seen in /proc/devices).
This function will unregister a block driver provided the "devfs=only" option was not provided at boot time. Returns 0 on success, else a negative error code on failure.