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>
diff --git a/include/linux/libata.h b/include/linux/libata.h
index b0d4ca0..f9f81fd 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -216,6 +216,7 @@
ATA_QCFLAG_DMAMAP = ATA_QCFLAG_SG | ATA_QCFLAG_SINGLE,
ATA_QCFLAG_IO = (1 << 3), /* standard IO command */
ATA_QCFLAG_RESULT_TF = (1 << 4), /* result TF requested */
+ ATA_QCFLAG_CLEAR_EXCL = (1 << 5), /* clear excl_link on completion */
ATA_QCFLAG_FAILED = (1 << 16), /* cmd failed and is owned by EH */
ATA_QCFLAG_SENSE_VALID = (1 << 17), /* sense data valid */
@@ -579,11 +580,13 @@
struct ata_queued_cmd qcmd[ATA_MAX_QUEUE];
unsigned long qc_allocated;
unsigned int qc_active;
+ int nr_active_links; /* #links with active qcs */
struct ata_link link; /* host default link */
int nr_pmp_links; /* nr of available PMP links */
struct ata_link *pmp_link; /* array of PMP links */
+ struct ata_link *excl_link; /* for PMP qc exclusion */
struct ata_port_stats stats;
struct ata_host *host;
@@ -1104,6 +1107,11 @@
return 1;
}
+static inline int ata_link_active(struct ata_link *link)
+{
+ return ata_tag_valid(link->active_tag) || link->sactive;
+}
+
static inline struct ata_link *ata_port_first_link(struct ata_port *ap)
{
if (ap->nr_pmp_links)