tree 214670f42be4c140bbd05226adc8f86db51ee725
parent 31cc23b34913bc173680bdc87af79e551bf8cc0d
author Tejun Heo <htejun@gmail.com> 1190520852 +0900
committer Jeff Garzik <jeff@garzik.org> 1192215341 -0400

libata-pmp-prep: implement qc_defer helpers

Implement ap->nr_active_links (the number of links with active qcs),
ap->excl_link (pointer to link which can be used by ->qc_defer and is
cleared when a qc with ATA_QCFLAG_CLEAR_EXCL completes), and
ata_link_active().

These can be used by ->qc_defer() to implement proper command
exclusion.  This set of helpers seem enough for both sil24 (ATAPI
exclusion needed) and cmd-switching PMP.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>