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 4.8.                 January 2017                           BLK_LLD_BUSY(9)