ata_std_qc_defer(9) centos man page | unix.com

ATA_STD_QC_DEFER(9)						  libata Library					       ATA_STD_QC_DEFER(9)

NAME
       ata_std_qc_defer - Check whether a qc needs to be deferred

SYNOPSIS
       int ata_std_qc_defer(struct ata_queued_cmd * qc);

ARGUMENTS
       qc
	   ATA command in question

DESCRIPTION
       Non-NCQ commands cannot run with any other command, NCQ or not. As upper layer only knows the queue depth, we are responsible for
       maintaining exclusion. This function checks whether a new command qc can be issued.

LOCKING
       spin_lock_irqsave(host lock)

RETURNS
       ATA_DEFER_* if deferring is needed, 0 otherwise.

AUTHOR
       Jeff Garzik
	   Author.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014						       ATA_STD_QC_DEFER(9)