blk_cloned_rq_check_limits - Helper function to check a cloned request for new the queue limits
int blk_cloned_rq_check_limits(struct request_queue * q, struct request * rq);
rq may have been made based on weaker limitations of upper-level queues in request stacking drivers, and it may violate the limitation of q. Since the block layer and the underlying device driver trust rq after it is inserted to q, it should be checked against q before the insertion using this generic function.
Request stacking drivers like request-based dm may change the queue limits when retrying requests on other queues. Those requests need to be checked against the new queue limits again during dispatch.
|January 2017||Kernel Hackers Manual 4.8.|