BLK_QUEUE_START_TAG(9)                    Block Devices                    BLK_QUEUE_START_TAG(9)



NAME
       blk_queue_start_tag - find a free tag and assign it

SYNOPSIS
       int blk_queue_start_tag(struct request_queue * q, struct request * rq);

ARGUMENTS
       q
           the request queue for the device

       rq
           the block request that needs tagging

DESCRIPTION
       This can either be used as a stand-alone helper, or possibly be assigned as the queue
       prep_rq_fn (in which case struct request automagically gets a tag assigned). Note that
       this function assumes that any type of request can be queued! if this is not true for your
       device, you must check the request type before calling this function. The request will
       also be removed from the request queue, so it's the drivers responsibility to readd it if
       it should need to be restarted for some reason.

NOTES
       queue lock must be held.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                    BLK_QUEUE_START_TAG(9)