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BLK_CLONED_RQ_CHECK_(9) Block Devices BLK_CLONED_RQ_CHECK_(9)

NAME

blk_cloned_rq_check_limits - Helper function to check a cloned request for new the queue limits

SYNOPSIS

int blk_cloned_rq_check_limits(struct request_queue * q, struct request * rq);

ARGUMENTS

q
the queue
rq
the request being checked

DESCRIPTION

 
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.

COPYRIGHT

February 2017 Kernel Hackers Manual 3.16