libata-sff: add ata_sff_queue_work() & ata_sff_queue_delayed_work()

This patch adds ata_sff_queue_work() & ata_sff_queue_delayed_work() routine in
libata-sff.c file. This routine can be used by ata drivers to use ata_sff_wq.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

drivers/ata/libata-sff.c

@@ -1302,6 +1302,18 @@ fsm_start:
 }
 EXPORT_SYMBOL_GPL(ata_sff_hsm_move);
 
+void ata_sff_queue_work(struct work_struct *work)
+{
+	queue_work(ata_sff_wq, work);
+}
+EXPORT_SYMBOL_GPL(ata_sff_queue_work);
+
+void ata_sff_queue_delayed_work(struct delayed_work *dwork, unsigned long delay)
+{
+	queue_delayed_work(ata_sff_wq, dwork, delay);
+}
+EXPORT_SYMBOL_GPL(ata_sff_queue_delayed_work);
+
 void ata_sff_queue_pio_task(struct ata_link *link, unsigned long delay)
 {
 	struct ata_port *ap = link->ap;
@@ -1311,8 +1323,7 @@ void ata_sff_queue_pio_task(struct ata_link *link, unsigned long delay)
 	ap->sff_pio_task_link = link;
 
 	/* may fail if ata_sff_flush_pio_task() in progress */
-	queue_delayed_work(ata_sff_wq, &ap->sff_pio_task,
-			   msecs_to_jiffies(delay));
+	ata_sff_queue_delayed_work(&ap->sff_pio_task, msecs_to_jiffies(delay));
 }
 EXPORT_SYMBOL_GPL(ata_sff_queue_pio_task);