[PATCH] libata: implement port_task
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@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 5dbcf0c..d59d462 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -721,6 +721,81 @@
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)
{
@@ -4617,6 +4692,7 @@
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);
@@ -5088,6 +5164,7 @@
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);