ata_scsi_queuecmd — Issue SCSI cdb to libata-managed device
SCSI command to be sent
Completion function, called when command is complete
In some cases, this function translates SCSI commands into ATA taskfiles, and queues the taskfiles to be sent to hardware. In other cases, this function simulates a SCSI device by evaluating and responding to certain SCSI commands. This creates the overall effect of ATA and ATAPI devices appearing as SCSI devices.
Releases scsi-layer-held lock, and obtains host lock.
Return value from __ata_scsi_queuecmd if cmd can be queued, 0 otherwise.