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 PM.
---
drivers/scsi/libata-core.c | 22 +++++++++++++++++++---
drivers/scsi/libata-eh.c | 5 +++++
include/linux/libata.h | 8 ++++++++
3 files changed, 32 insertions(+), 3 deletions(-)
7deb1fc49ea4e26d9f1bc4258094086e0bcb27f2
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 5dd5a28..fb64a0f 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -994,7 +994,6 @@ void ata_qc_complete_internal(struct ata
* LOCKING:
* None. Should be called with kernel context, might sleep.
*/
-
unsigned ata_exec_internal(struct ata_device *dev,
struct ata_taskfile *tf, const u8 *cdb,
int dma_dir, void *buf, unsigned int buflen)
@@ -1005,6 +1004,7 @@ unsigned ata_exec_internal(struct ata_de
struct ata_queued_cmd *qc;
unsigned int tag, preempted_tag;
u32 preempted_sactive, preempted_qc_active;
+ int preempted_nr_active_links;
DECLARE_COMPLETION(wait);
unsigned long flags;
unsigned int err_mask;
@@ -1043,9 +1043,11 @@ unsigned ata_exec_internal(struct ata_de
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;
@@ -1112,6 +1114,7 @@ unsigned ata_exec_internal(struct ata_de
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
@@ -4327,10 +4330,18 @@ void __ata_qc_complete(struct ata_queued
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 = NULL;
/* atapi: mark qc as inactive to prevent the interrupt handler
* from completing the command twice later, before the error handler
@@ -4503,9 +4514,14 @@ void ata_qc_issue(struct ata_queued_cmd
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;
}
diff --git a/drivers/scsi/libata-eh.c b/drivers/scsi/libata-eh.c
index 3764e21..ffbd028 100644
--- a/drivers/scsi/libata-eh.c
+++ b/drivers/scsi/libata-eh.c
@@ -248,6 +248,7 @@ void ata_scsi_error(struct Scsi_Host *ho
}
ap->flags &= ~ATA_FLAG_EH_PENDING;
+ ap->excl_link = NULL; /* don't maintain exclusion over EH */
spin_unlock_irqrestore(hs_lock, flags);
@@ -1873,6 +1874,10 @@ 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;
}
static void ata_eh_scsi_handle_link_detach(struct ata_link *link)
diff --git a/include/linux/libata.h b/include/linux/libata.h
index a26b6a6..df78f3e 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -181,6 +181,7 @@ 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 */
@@ -520,12 +521,14 @@ 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 */
struct ata_device __dev1; /* storage for link.device[1] */
int nr_pm_links; /* nr of available PM links */
struct ata_link *pm_link; /* array of PM links */
+ struct ata_link *excl_link; /* for PM qc exclusion */
struct ata_host_stats stats;
struct ata_host_set *host_set;
@@ -931,6 +934,11 @@ static inline int ata_link_max_devices(c
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_pm_links)
--
1.2.4
-
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