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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>
This commit is contained in:
Tejun Heo 2007-09-23 13:14:12 +09:00 committed by Jeff Garzik
parent 31cc23b349
commit da917d69d0
3 changed files with 33 additions and 2 deletions
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22
drivers/ata/libata-core.c
View File

@ -1390,6 +1390,7 @@ unsigned ata_exec_internal_sg(struct ata_device *dev,
struct ata_queued_cmd *qc;
unsigned int tag, preempted_tag;
u32 preempted_sactive, preempted_qc_active;
int preempted_nr_active_links;
DECLARE_COMPLETION_ONSTACK(wait);
unsigned long flags;
unsigned int err_mask;
@ -1428,9 +1429,11 @@ unsigned ata_exec_internal_sg(struct ata_device *dev,
preempted_tag = link->active_tag;
preempted_sactive = link->sactive;
preempted_qc_active = ap->qc_active;
preempted_nr_active_links = ap->nr_active_links;
link->active_tag = ATA_TAG_POISON;
link->sactive = 0;
ap->qc_active = 0;
ap->nr_active_links = 0;
/* prepare & issue qc */
qc->tf = *tf;
@ -1509,6 +1512,7 @@ unsigned ata_exec_internal_sg(struct ata_device *dev,
link->active_tag = preempted_tag;
link->sactive = preempted_sactive;
ap->qc_active = preempted_qc_active;
ap->nr_active_links = preempted_nr_active_links;
/* XXX - Some LLDDs (sata_mv) disable port on command failure.
* Until those drivers are fixed, we detect the condition
@ -5408,10 +5412,19 @@ void __ata_qc_complete(struct ata_queued_cmd *qc)
ata_sg_clean(qc);
/* command should be marked inactive atomically with qc completion */
if (qc->tf.protocol == ATA_PROT_NCQ)
if (qc->tf.protocol == ATA_PROT_NCQ) {
link->sactive &= ~(1 << qc->tag);
else
if (!link->sactive)
ap->nr_active_links--;
} else {
link->active_tag = ATA_TAG_POISON;
ap->nr_active_links--;
}
/* clear exclusive status */
if (unlikely(qc->flags & ATA_QCFLAG_CLEAR_EXCL &&
ap->excl_link == link))
ap->excl_link = NULL;
/* atapi: mark qc as inactive to prevent the interrupt handler
* from completing the command twice later, before the error handler
@ -5590,9 +5603,14 @@ void ata_qc_issue(struct ata_queued_cmd *qc)
if (qc->tf.protocol == ATA_PROT_NCQ) {
WARN_ON(link->sactive & (1 << qc->tag));
if (!link->sactive)
ap->nr_active_links++;
link->sactive |= 1 << qc->tag;
} else {
WARN_ON(link->sactive);
ap->nr_active_links++;
link->active_tag = qc->tag;
}

5
drivers/ata/libata-eh.c
View File

@ -451,6 +451,7 @@ void ata_scsi_error(struct Scsi_Host *host)
ap->pflags |= ATA_PFLAG_EH_IN_PROGRESS;
ap->pflags &= ~ATA_PFLAG_EH_PENDING;
ap->excl_link = NULL; /* don't maintain exclusion over EH */
spin_unlock_irqrestore(ap->lock, flags);
@ -2474,6 +2475,10 @@ void ata_eh_finish(struct ata_port *ap)
}
}
}
/* make sure nr_active_links is zero after EH */
WARN_ON(ap->nr_active_links);
ap->nr_active_links = 0;
}
/**

8
include/linux/libata.h
View File

@ -216,6 +216,7 @@ enum {
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_port {
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 @@ static inline int ata_link_max_devices(const struct ata_link *link)
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)