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

Ends I/O on a number of bytes attached to rq. If rq has leftover, sets it up for the next range of segments.

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