BLK_QUEUE_START_TAG(9) Block Devices BLK_QUEUE_START_TAG(9)NAMEblk_queue_start_tag - find a free tag and assign it
int blk_queue_start_tag(struct request_queue * q, struct request * rq);
the request queue for the device
the block request that needs tagging
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.
queue lock must be held.
COPYRIGHTKernel Hackers Manual 3.8. June 2014 BLK_QUEUE_START_TAG(9)