Man page 9 : __blk_end_request

__blk_end_request - Helper function for drivers to complete the request.

bool __blk_end_request(struct request *  rq , int  error , unsigned int  nr_bytes );

rq
    the request being processed

error
     0 for success, < 0 for error

nr_bytes
    number of bytes to complete

Must be called with queue lock held unlike blk_end_request.

false - we are done with this request true - still buffers pending for this request