libata-sff: port_task is SFF specific

port_task is tightly bound to the standard SFF PIO HSM implementation.
Using it for any other purpose would be error-prone and there's no
such user and if some drivers need such feature, it would be much
better off using its own.  Move it inside CONFIG_ATA_SFF and rename it
to sff_pio_task.

The only function which is exposed to the core layer is
ata_sff_flush_pio_task() which is renamed from ata_port_flush_task()
and now also takes care of resetting hsm_task_state to HSM_ST_IDLE,
which is possible as it's now specific to PIO HSM.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 54 insertions, 18 deletions

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 8a1396f52a3a..e78ad76861f4 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -40,6 +40,8 @@
 
 #include "libata.h"
 
+static struct workqueue_struct *ata_sff_wq;
+
 const struct ata_port_operations ata_sff_port_ops = {
         .inherits               = &ata_base_port_ops,
 
@@ -1293,7 +1295,7 @@ fsm_start:
                 if (in_wq)
                         spin_unlock_irqrestore(ap->lock, flags);
 
-                /* if polling, ata_pio_task() handles the rest.
+                /* if polling, ata_sff_pio_task() handles the rest.
                  * otherwise, interrupt handler takes over from here.
                  */
                 break;
@@ -1458,14 +1460,38 @@ fsm_start:
 }
 EXPORT_SYMBOL_GPL(ata_sff_hsm_move);
 
-void ata_pio_task(struct work_struct *work)
+void ata_sff_queue_pio_task(struct ata_port *ap, unsigned long delay)
+{
+        /* may fail if ata_sff_flush_pio_task() in progress */
+        queue_delayed_work(ata_sff_wq, &ap->sff_pio_task,
+                           msecs_to_jiffies(delay));
+}
+EXPORT_SYMBOL_GPL(ata_sff_queue_pio_task);
+
+void ata_sff_flush_pio_task(struct ata_port *ap)
+{
+        DPRINTK("ENTER\n");
+
+        cancel_rearming_delayed_work(&ap->sff_pio_task);
+        ap->hsm_task_state = HSM_ST_IDLE;
+
+        if (ata_msg_ctl(ap))
+                ata_port_printk(ap, KERN_DEBUG, "%s: EXIT\n", __func__);
+}
+
+static void ata_sff_pio_task(struct work_struct *work)
 {
         struct ata_port *ap =
-                container_of(work, struct ata_port, port_task.work);
-        struct ata_queued_cmd *qc = ap->port_task_data;
+                container_of(work, struct ata_port, sff_pio_task.work);
+        struct ata_queued_cmd *qc;
         u8 status;
         int poll_next;
 
+        /* qc can be NULL if timeout occurred */
+        qc = ata_qc_from_tag(ap, ap->link.active_tag);
+        if (!qc)
+                return;
+
 fsm_start:
         WARN_ON_ONCE(ap->hsm_task_state == HSM_ST_IDLE);
 
@@ -1481,7 +1507,7 @@ fsm_start:
                 msleep(2);
                 status = ata_sff_busy_wait(ap, ATA_BUSY, 10);
                 if (status & ATA_BUSY) {
-                        ata_pio_queue_task(ap, qc, ATA_SHORT_PAUSE);
+                        ata_sff_queue_pio_task(ap, ATA_SHORT_PAUSE);
                         return;
                 }
         }
@@ -1551,7 +1577,7 @@ unsigned int ata_sff_qc_issue(struct ata_queued_cmd *qc)
                 ap->hsm_task_state = HSM_ST_LAST;
 
                 if (qc->tf.flags & ATA_TFLAG_POLLING)
-                        ata_pio_queue_task(ap, qc, 0);
+                        ata_sff_queue_pio_task(ap, 0);
 
                 break;
 
@@ -1573,20 +1599,21 @@ unsigned int ata_sff_qc_issue(struct ata_queued_cmd *qc)
                 if (qc->tf.flags & ATA_TFLAG_WRITE) {
                         /* PIO data out protocol */
                         ap->hsm_task_state = HSM_ST_FIRST;
-                        ata_pio_queue_task(ap, qc, 0);
+                        ata_sff_queue_pio_task(ap, 0);
 
-                        /* always send first data block using
-                         * the ata_pio_task() codepath.
+                        /* always send first data block using the
+                         * ata_sff_pio_task() codepath.
                          */
                 } else {
                         /* PIO data in protocol */
                         ap->hsm_task_state = HSM_ST;
 
                         if (qc->tf.flags & ATA_TFLAG_POLLING)
-                                ata_pio_queue_task(ap, qc, 0);
+                                ata_sff_queue_pio_task(ap, 0);
 
-                        /* if polling, ata_pio_task() handles the rest.
-                         * otherwise, interrupt handler takes over from here.
+                        /* if polling, ata_sff_pio_task() handles the
+                         * rest.  otherwise, interrupt handler takes
+                         * over from here.
                          */
                 }
 
@@ -1604,7 +1631,7 @@ unsigned int ata_sff_qc_issue(struct ata_queued_cmd *qc)
                 /* send cdb by polling if no cdb interrupt */
                 if ((!(qc->dev->flags & ATA_DFLAG_CDB_INTR)) ||
                     (qc->tf.flags & ATA_TFLAG_POLLING))
-                        ata_pio_queue_task(ap, qc, 0);
+                        ata_sff_queue_pio_task(ap, 0);
                 break;
 
         case ATAPI_PROT_DMA:
@@ -1616,7 +1643,7 @@ unsigned int ata_sff_qc_issue(struct ata_queued_cmd *qc)
 
                 /* send cdb by polling if no cdb interrupt */
                 if (!(qc->dev->flags & ATA_DFLAG_CDB_INTR))
-                        ata_pio_queue_task(ap, qc, 0);
+                        ata_sff_queue_pio_task(ap, 0);
                 break;
 
         default:
@@ -2360,8 +2387,6 @@ void ata_sff_error_handler(struct ata_port *ap)
         /* reset PIO HSM and stop DMA engine */
         spin_lock_irqsave(ap->lock, flags);
 
-        ap->hsm_task_state = HSM_ST_IDLE;
-
         if (ap->ioaddr.bmdma_addr &&
             qc && (qc->tf.protocol == ATA_PROT_DMA ||
                    qc->tf.protocol == ATAPI_PROT_DMA)) {
@@ -2432,8 +2457,6 @@ void ata_sff_post_internal_cmd(struct ata_queued_cmd *qc)
 
         spin_lock_irqsave(ap->lock, flags);
 
-        ap->hsm_task_state = HSM_ST_IDLE;
-
         if (ap->ioaddr.bmdma_addr)
                 ap->ops->bmdma_stop(qc);
 
@@ -3074,15 +3097,28 @@ EXPORT_SYMBOL_GPL(ata_pci_bmdma_init);
  */
 void ata_sff_port_init(struct ata_port *ap)
 {
+        INIT_DELAYED_WORK(&ap->sff_pio_task, ata_sff_pio_task);
         ap->ctl = ATA_DEVCTL_OBS;
         ap->last_ctl = 0xFF;
 }
 
 int __init ata_sff_init(void)
 {
+        /*
+         * FIXME: In UP case, there is only one workqueue thread and if you
+         * have more than one PIO device, latency is bloody awful, with
+         * occasional multi-second "hiccups" as one PIO device waits for
+         * another.  It's an ugly wart that users DO occasionally complain
+         * about; luckily most users have at most one PIO polled device.
+         */
+        ata_sff_wq = create_workqueue("ata_sff");
+        if (!ata_sff_wq)
+                return -ENOMEM;
+
         return 0;
 }
 
 void __exit ata_sff_exit(void)
 {
+        destroy_workqueue(ata_sff_wq);
 }