libata-pmp-prep: implement qc_defer helpers
authorTejun Heo <htejun@gmail.com>
Sun, 23 Sep 2007 04:14:12 +0000 (13:14 +0900)
committerJeff Garzik <jeff@garzik.org>
Fri, 12 Oct 2007 18:55:41 +0000 (14:55 -0400)
commitda917d69d0ea63f5390716cba6e77f490ce96df9
tree214670f42be4c140bbd05226adc8f86db51ee725
parent31cc23b34913bc173680bdc87af79e551bf8cc0d
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>
drivers/ata/libata-core.c
drivers/ata/libata-eh.c
include/linux/libata.h