BLK_LLD_BUSY(9) Block Devices BLK_LLD_BUSY(9)NAMEblk_lld_busy - Check if underlying low-level drivers of a device are
busy
SYNOPSIS
int blk_lld_busy(struct request_queue * q);
ARGUMENTS
q
the queue of the device being checked
DESCRIPTION
Check if underlying low-level drivers of a device are busy. If the
drivers want to export their busy state, they must set own exporting
function using blk_queue_lld_busy first.
Basically, this function is used only by request stacking drivers to
stop dispatching requests to underlying devices when underlying devices
are busy. This behavior helps more I/O merging on the queue of the
request stacking driver and prevents I/O throughput regression on burst
I/O load.
RETURN
0 - Not busy (The request stacking driver should dispatch request) 1 -
Busy (The request stacking driver should stop dispatching request)
COPYRIGHTKernel Hackers Manual 2.6. November 2013 BLK_LLD_BUSY(9)