BLK_LLD_BUSY(9) Block Devices BLK_LLD_BUSY(9)
NAME
blk_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)
COPYRIGHT
Kernel Hackers Manual 2.6. July 2010 BLK_LLD_BUSY(9)
