BLK_STOP_QUEUE(9) Block Devices BLK_STOP_QUEUE(9)
NAME blk_stop_queue - stop a queue
SYNOPSIS void blk_stop_queue(struct request_queue * q);
ARGUMENTS q The struct request_queue in question
DESCRIPTION The Linux block layer assumes that a block driver will consume all entries on the request queue when the request_fn strategy is called. Often this will not happen, because of hardware limitations (queue depth settings). If a device driver gets a ´queue full´ response, or if it simply chooses not to queue more I/O at one point, it can call this function to prevent the request_fn from being called until the driver has signalled it´s ready to go again. This happens by calling blk_start_queue to restart queue operations. Queue lock must be held.
COPYRIGHT Kernel Hackers Manual 2.6. November 2013 BLK_STOP_QUEUE(9)