Implement port_task. LLDD's can schedule a function to be executed
with context after specified delay. libata core takes care of
synchronization against EH. This is generalized form of pio_task and
packet_task which are tied to PIO hsm implementation.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
---
drivers/scsi/libata-core.c | 77 ++++++++++++++++++++++++++++++++++++++++++++
drivers/scsi/libata-scsi.c | 2 +
drivers/scsi/libata.h | 1 +
include/linux/libata.h | 4 ++
4 files changed, 84 insertions(+), 0 deletions(-)
4d83950873856672ed469f25c6421de1eb98ba97
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index b710fc4..3575d68 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -721,6 +721,81 @@ static unsigned int ata_pio_modes(const
timing API will get this right anyway */
}
+/**
+ * ata_port_queue_task - Queue port_task
+ * @ap: The ata_port to queue port_task for
+ *
+ * Schedule @fn(@data) for execution after @delay jiffies using
+ * port_task. There is one port_task per port and it's the
+ * user(low level driver)'s responsibility to make sure that only
+ * one task is active at any given time.
+ *
+ * libata core layer takes care of synchronization between
+ * port_task and EH. ata_port_queue_task() may be ignored for EH
+ * synchronization.
+ *
+ * LOCKING:
+ * Inherited from caller.
+ */
+void ata_port_queue_task(struct ata_port *ap, void (*fn)(void *), void *data,
+ unsigned long delay)
+{
+ int rc;
+
+ if (ap->flags & ATA_FLAG_FLUSH_PIO_TASK)
+ return;
+
+ PREPARE_WORK(&ap->port_task, fn, data);
+
+ if (!delay)
+ rc = queue_work(ata_wq, &ap->port_task);
+ else
+ rc = queue_delayed_work(ata_wq, &ap->port_task, delay);
+
+ /* rc == 0 means that another user is using port task */
+ WARN_ON(rc == 0);
+}
+
+/**
+ * ata_port_flush_task - Flush port_task
+ * @ap: The ata_port to flush port_task for
+ *
+ * After this function completes, port_task is guranteed not to
+ * be running or scheduled.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep)
+ */
+void ata_port_flush_task(struct ata_port *ap)
+{
+ unsigned long flags;
+
+ DPRINTK("ENTER\n");
+
+ spin_lock_irqsave(&ap->host_set->lock, flags);
+ ap->flags |= ATA_FLAG_FLUSH_PIO_TASK;
+ spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+ DPRINTK("flush #1\n");
+ flush_workqueue(ata_wq);
+
+ /*
+ * At this point, if a task is running, it's guaranteed to see
+ * the FLUSH flag; thus, it will never queue pio tasks again.
+ * Cancel and flush.
+ */
+ if (!cancel_delayed_work(&ap->port_task)) {
+ DPRINTK("flush #2\n");
+ flush_workqueue(ata_wq);
+ }
+
+ spin_lock_irqsave(&ap->host_set->lock, flags);
+ ap->flags &= ~ATA_FLAG_FLUSH_PIO_TASK;
+ spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+ DPRINTK("EXIT\n");
+}
+
static inline void
ata_queue_packet_task(struct ata_port *ap)
{
@@ -4478,6 +4553,7 @@ static void ata_host_init(struct ata_por
ap->active_tag = ATA_TAG_POISON;
ap->last_ctl = 0xFF;
+ INIT_WORK(&ap->port_task, NULL, NULL);
INIT_WORK(&ap->packet_task, atapi_packet_task, ap);
INIT_WORK(&ap->pio_task, ata_pio_task, ap);
INIT_LIST_HEAD(&ap->eh_done_q);
@@ -4948,6 +5024,7 @@ EXPORT_SYMBOL_GPL(ata_drive_probe_reset)
EXPORT_SYMBOL_GPL(ata_port_disable);
EXPORT_SYMBOL_GPL(ata_ratelimit);
EXPORT_SYMBOL_GPL(ata_busy_sleep);
+EXPORT_SYMBOL_GPL(ata_port_queue_task);
EXPORT_SYMBOL_GPL(ata_scsi_ioctl);
EXPORT_SYMBOL_GPL(ata_scsi_queuecmd);
EXPORT_SYMBOL_GPL(ata_scsi_timed_out);
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index d0bd94a..ccedb45 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -785,6 +785,8 @@ int ata_scsi_error(struct Scsi_Host *hos
WARN_ON(ata_qc_from_tag(ap, ap->active_tag) == NULL);
spin_unlock_irqrestore(&ap->host_set->lock, flags);
+ ata_port_flush_task(ap);
+
ap->ops->eng_timeout(ap);
WARN_ON(host->host_failed || !list_empty(&host->eh_cmd_q));
diff --git a/drivers/scsi/libata.h b/drivers/scsi/libata.h
index d822eba..f4c48c9 100644
--- a/drivers/scsi/libata.h
+++ b/drivers/scsi/libata.h
@@ -45,6 +45,7 @@ extern int libata_fua;
extern struct ata_queued_cmd *ata_qc_new_init(struct ata_port *ap,
struct ata_device *dev);
extern int ata_rwcmd_protocol(struct ata_queued_cmd *qc);
+extern void ata_port_flush_task(struct ata_port *ap);
extern void ata_qc_free(struct ata_queued_cmd *qc);
extern unsigned int ata_qc_issue(struct ata_queued_cmd *qc);
extern int ata_check_atapi_dma(struct ata_queued_cmd *qc);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 86a504f..abc5c6e 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -388,6 +388,8 @@ struct ata_port {
struct ata_host_stats stats;
struct ata_host_set *host_set;
+ struct work_struct port_task;
+
struct work_struct packet_task;
struct work_struct pio_task;
@@ -513,6 +515,8 @@ extern int ata_ratelimit(void);
extern unsigned int ata_busy_sleep(struct ata_port *ap,
unsigned long timeout_pat,
unsigned long timeout);
+extern void ata_port_queue_task(struct ata_port *ap, void (*fn)(void *),
+ void *data, unsigned long delay);
/*
* Default driver ops implementations
--
1.2.1
-
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